Scipedia: Documents published in 2019

Stability of Propofol (2,6-Diisopropylphenol) in Thermal Desorption Tubes during Air Transport

Scipedia content — Thu, 28 Jan 2021 19:36:24 +0100

The anesthetic propofol and other exhaled organic compounds can be sampled in Tenax sorbent tubes and analyzed by gas chromatography coupled with mass spectrometry. The aim of this study was to evaluate the stability of propofol in Tenax sorbent tubes during overseas shipping. This is relevant for international pharmacokinetic studies on propofol in exhaled air. Tenax sorbent tube propofol samples with concentrations between 10 and 100 ng were prepared by liquid injection and with a calibration gas generator. For each preparation method, one reference set was analyzed immediately after preparation, a second set was stored at room temperature, and a third one was stored refrigerated. The fourth set was sent from Germany by airmail to USA and back. The shipped set of tubes was analyzed when it returned after 55 days elapsed. Then, the room temperature samples and the refrigerated stored samples were also analyzed. To evaluate the stability of propofol in the stored and shipped tubes, we calculated the recovery rates of each sample set. The mean recovery in the stored samples was 101.2% for the liquid preparation and 134.6% for the gaseous preparation at 4°C. At 22°C, the recovery was 96.1% for liquid preparation and 92.1% for gaseous preparation, whereas the shipped samples had a recovery of 85.3% and 111.3%. Thus, the deviation of the shipped samples is within a range of 15%, which is analytically acceptable. However, the individual values show significantly larger deviations of up to -32.1% (liquid) and 30.9% (gaseous). We conclude that storage of propofol on Tenax tubes at room temperature for 55 days is possible to obtain acceptable results. However, it appears that due to severe temperature and pressure variations air shipment of propofol samples in Tenax tubes without cooling shows severe deviations from the initial concentration. Although it was not tested in this study, we assume that refrigerated transport might be necessary to obtain comparable results as in the stored samples.

Document type: Article

Management of Oil Transportation via Main Pipelines using SCADA System Data

Scipedia content — Thu, 28 Jan 2021 19:35:47 +0100

Preliminary Inter-comparison of AIS Data and Optimal Ship Tracks

Scipedia content — Thu, 28 Jan 2021 19:31:42 +0100

Optimal ship tracks computed via the VISIR model are compared to tracks recorded by the Automatic Identification System (AIS). The evaluation regards 43 tracks in the Southern Atlantic Ocean, sailed during 2016-2017 by different bulk carriers. In this exercise, VISIR is fed by wave analysis fields from the Copernicus Marine Environment Monitoring Service (CMEMS). In order to reproduce vessel speed loss in waves, a new methodology is developed, where kinematic information from AIS is fusioned with wave information from CMEMS. Resulting VISIR tracks are analyzed along with AIS tracks in terms of their topological features and duration. The tracks exhibit quite diverse topological shapes, including orthodromic, loxodromic, and other paths with complex and dynamic diversions. The distribution of AIS to VISIR track durations is analyzed in terms of several parameters, such as the AIS to VISIR track length and their Fréchet distance. Model features of VISIR affecting the results are discussed and future developments suggested by the results are outlined.

Obduracy and Change in Urban Transport—Understanding Competition Between Sustainable Fuels in Swedish Municipalities

Scipedia content — Thu, 28 Jan 2021 19:31:12 +0100

Within the renewable transport transition, a number of alternative technologies have emerged creating competing visions of how to reduce fossil fuel dependence. This paper examines the dynamics of competing fuels in two Swedish municipalities where electric buses have emerged, threatening incumbent biogas-based bus systems. While in Linkö

ping, actors are resistant to the promise of electrification, in Malmö

the shift to electrify urban buses has already begun. Here, the theoretical perspectives of obduracy and sociotechnical imaginaries are used to analyze obduracy and change in Linkö

ping and Malmö

, showing how the local contexts of these two municipalities influence obduracy or willingness to change. In Linkö

ping, perceived connections between the biogas-based bus system and local infrastructures of renewable waste management and organic food production cause actors to place biogas buses at the center of a sustainable future region, while in Malmö

linkages to the gas network (which also distributes natural gas) cause actors to question the sustainability of the fuel in use and opens up the city to welcome new electric vehicle tests. These examples show how fuel alternatives interact with each other in the wider renewable energy transition.

Document type: Article

Towards Robust Product Packing with a Minimalistic End-Effector

Scipedia content — Thu, 28 Jan 2021 19:28:31 +0100

dvances in sensor technologies, object detection algorithms, planning frameworks and hardware designs have motivated the deployment of robots in warehouse automation. A variety of such applications, like order fulfillment or packing tasks, require picking objects from unstructured piles and carefully arranging them in bins or containers. Desirable solutions need to be low-cost, easily deployable and controllable, making minimalistic hardware choices desirable. The challenge in designing an effective solution to this problem relates to appropriately integrating multiple components, so as to achieve a robust pipeline that minimizes failure conditions. The current work proposes a complete pipeline for solving such packing tasks, given access only to RGB-D data and a single robot arm with a vacuum-based end-effector, which is also used as a pushing finger. To achieve the desired level of robustness, three key manipulation primitives are identified, which take advantage of the environment and simple operations to successfully pack multiple cubic objects. The overall approach is demonstrated to be robust to execution and perception errors. The impact of each manipulation primitive is evaluated by considering different versions of the proposed pipeline, which incrementally introduce reasoning about object poses and corrective manipulation actions.

ITS Design Priority at Large Bus Terminal in Indonesia in Supporting Sustainable Transportation

Scipedia content — Thu, 28 Jan 2021 19:25:51 +0100

MultiDepth: Single-Image Depth Estimation via Multi-Task Regression and Classification

Scipedia content — Thu, 28 Jan 2021 19:21:10 +0100

We introduce MultiDepth, a novel training strategy and convolutional neural network (CNN) architecture that allows approaching single-image depth estimation (SIDE) as a multi-task problem. SIDE is an important part of road scene understanding. It, thus, plays a vital role in advanced driver assistance systems and autonomous vehicles. Best results for the SIDE task so far have been achieved using deep CNNs. However, optimization of regression problems, such as estimating depth, is still a challenging task. For the related tasks of image classification and semantic segmentation, numerous CNN-based methods with robust training behavior have been proposed. Hence, in order to overcome the notorious instability and slow convergence of depth value regression during training, MultiDepth makes use of depth interval classification as an auxiliary task. The auxiliary task can be disabled at test-time to predict continuous depth values using the main regression branch more efficiently. We applied MultiDepth to road scenes and present results on the KITTI depth prediction dataset. In experiments, we were able to show that end-to-end multi-task learning with both, regression and classification, is able to considerably improve training and yield more accurate results.

Comment: Accepted for presentation at the IEEE Intelligent Transportation Systems Conference (ITSC) 2019

An Automated Fire Suppression Mechanism Controlled using an Arduino

Scipedia content — Thu, 28 Jan 2021 19:17:34 +0100

The presented fire suppression mechanism is a self-monitoring system that detects the existence of fire between a specific range of wavelength and suppresses the fire by spreading water flowing via multiple sprinkler-heads. The controlling unit used to manipulate the fire suppression mechanism is an Arduino Uno. The major advantage of this system is its capability to detect fire fast and run water through dedicated pipes using solenoid valve. Fire is an undesirable event that could cause a great loss of social wealth, human life, and confidential amenities. To prevent these losses, various extinguishing systems have already been developed, such as sprinkler heads with temperature sensitive valve and temperature sensor based systems. These systems come with a high chance of delayed sensing and human error that can mislead the sensing and hence the whole system in general. Our fire suppression system, on the other hand, is extremely well thought out; it has no chance of human error as it is fully self-sufficient. The room or the area will have dedicated overhead sprinklers connected to the water supply through its dedicated solenoid valve which controls the flow of water in the pipelines. The triggering devices of this system are the flame sensors, when they detect fire an alarm will go off. The Algorithm set in the Arduino will come into work and an optimal voltage will be provided to the solenoid valve through a relay, hence water will rush out the sprinklers to extinguish the fire in no time. The sensors used are highly sensitive[5], thus it will detect fire even before it reaches a point of concern. Unlike other systems, the components we used are readily available and reasonable in price. Also, the system has been tested to extinguish fire in real-world scale. Our automated fire suppression system can be used both for commercial and residential purposes.

WISDOM

Scipedia content — Thu, 28 Jan 2021 18:53:17 +0100

lawn irrigation is estimated to consume 7 billion gallons of scarce fresh water each day in North America alone, lawn irrigation systems are a high priority for improvements in efficiency. To this end, recent work has introduced several key advancements in irrigation control. Distributed actuation systems allow the irrigation system to apply water completely independently across the field allowing flexibility of control, and the use of fluid flow modeling and optimization allows more efficient schedules to be computed automatically, significantly improving the irrigation quality of service as well. However, the proposed systems are designed with centralized architectures that introduce single points of failure, computational bottlenecks in data processing, and significant network energy for data forwarding used by the centralized data-driven modeling strategies. In response to these challenges, we propose and demonstrate WISDOM, whose novel and flexible hardware and processing pipelines enable the use of a distributed system for the management of irrigation systems of any scale, with energy independence by way of energy harvesting. Across 4 weeks of live system deployment, we find that the WISDOM system can save up to 32.9% of water in comparison to industry-best, while maintaining a perfect quality of service to the plant. Furthermore, with substantial analysis in simulation we find that in addition to practical system improvements, the use of the proposed distributed system within typical operating conditions will provide all of the efficiency and quality-of-service benefits of the globally-modeled, centrally controlled systems, while allowing the robust control of irrigation systems of any size.

Exploring the Potential Benefits of Multi-Aircraft Trajectory Manipulation in Future Air Traffic Control

Scipedia content — Thu, 28 Jan 2021 18:50:41 +0100

Future Air Traffic Management is expected to shift towards four dimensional trajectory (4DT) management, requiring new decision support tools for air traffic controllers to meet stringent time and position constraints. In previous work, a prototype human-machine interface has been developed for 4D trajectory manipulations of single aircraft. This paper describes a tool for multi-aircraft manipulation and investigates its potential control efficiency benefits. A human-in-the-loop experiment (N = 13) has been conducted using scenarios with sector disruptions and varying conflict geometry. Results show that participants preferred to use multi-aircraft manipulation for groups of aircraft having small convergence angles. Since the current implementation involves re-routing all selected aircraft through one common waypoint (referred to as a 'merge point'), extra additional track miles were flown and airspace robustness reduces. Regarding efficiency and safety, multi-aircraft trajectory manipulation seems favourable only for smaller convergence angles, although this also depends on the way the operators place the aircraft merging points. For future development, attention should be devoted to making flight efficiency constraints of each aircraft more salient, enabling controllers to better time the rerouting multiple aircraft and more fairly distribute re-routing costs.

Optimization of a Cascaded H-Bridge Inverter for Electric Vehicle Applications Including Cost Consideration

Scipedia content — Thu, 28 Jan 2021 18:50:28 +0100

This paper presents a method to find the optimal configuration for an electric vehicle energy storage system using a cascaded H-bridge (CHB) inverter. CHB multilevel inverters enable a better utilization of the battery pack, because cells/modules with manufacturing tolerances in terms of capacity can be selectively discharged instead of being passively balanced by discharging them over resistors. The balancing algorithms have been investigated in many studies for the CHB topology. However, it has not yet been investigated to which extend a conventional pack can be modularized in a CHB configuration. Therefore, this paper explores different configurations by simulating different switch models, switch configurations, and number of levels for a CHB inverter along with a reference load model to find the optimal design of the system. The configuration is also considered from an economically point of view, as the most efficient solution might not be cost-effective to be installed in a common production vehicle. It is found that four modules per phase give the best compromise between efficiency and costs. Paralleling smaller switches should be preferred over the usage of fewer, larger switches. Moreover, selecting specific existing components results in higher savings compared to theoretical optimal components.

Document type: Article

Research on transportation of metallurgical slag of tippers in the conditions of southeast of Ukraine

Scipedia content — Thu, 28 Jan 2021 18:48:23 +0100

Research aim - to produce conclusions that will result in the increase of the productivity and reduction of specific expense of fuel of tippers, while taking into account the tippers operational characteristics at transportation of metallurgical slags and products of their processing.. As a result of research the analysis of tippers of BelAZ-7540 exploitation was conducted on a metallurgical enterprise in the climactic conditions of southeast of Ukraine,. In addition, factors contributing to the efficiency of the tippers use have been distinguished and examined. It was found that the efficiency of the use of tippers, namely the studied change of expense of fuel is contingent on the work of tippers. Thus, in the process of research, there was the educed periodicity of oscillation of expense of fuel of tippers. The application of the research findings is that appropriate procedures are recommended in terms of the rational use of fuel, in particular, in the process of determination, planning, setting of norms of the necessary amount of fuel, which is one of the most essential and actual tasks for modern metallurgical enterprises today.

ComplexTrans – global land transportation system: the best way ahead for railways and roads is coherent cooperation, not the competition

Scipedia content — Thu, 28 Jan 2021 18:42:54 +0100

The land-transportation cannot meet its demands anymore. Jammed highways and cities, dangerous emissions, omnipresent traffic accidents, delays, expensive railways. Solutions are being sought to transfer a large part of passenger- and especially freight-traffic to (high-speed) rail and the efforts are shifting towards electromobility, car-sharing, 5G-connectivity, autonomous ride, MaaS-transport-coordination or Hyperloop-type solutions. However, all these solutions have further problems and limitations. Solutions are not sought where they really exist - in the mutual adaptation of the road and rail vehicles and their deep cooperation. The ComplexTrans-project shows that simply adapting dimensions and functions of the road and rail vehicles can eliminate (or at least substantially reduce) all the problems of existing land transport. The main features of the ComplexTrans system are sufficient parking spaces, reduced traffic density inside and outside of the cities, electric-vehicles with unlimited range and cheaper than the standard cars, cheaper and affordable recharging of batteries, autonomous ride, self-financing rail-transport, transfer of intercity freight to rail, replacement of part of the continental air-transport and many others.

URBAN MOBILITY STRATEGIES TO IMPROVE LOCAL AIR QUALITY: CASE STUDY OF LISBON, PORTUGAL

Scipedia content — Thu, 28 Jan 2021 18:42:09 +0100

Let there be Chaining: How to Augment your IGP to Chain your Services

Scipedia content — Thu, 28 Jan 2021 18:39:47 +0100

Ever since Network Functions Virtualization has replaced dedicated appliances, ISPs have been able to add a degree of flexibility in their traffic engineering. However, it also has increased the complexity of the optimization problem, because it is now necessary to place virtual functions and route traffic jointly. Insofar, a logically centralized approach has been taken, where a so-called orchestrator, having full knowledge of the network, the virtual functions, and the traffic, run complex algorithms to find a suitable solution to the problem. The outcome of the algorithms are then translated to network configurations to be pushed to all of the appliances. We argue that there is no need to fully centralize every decision, rather we can leverage existing network intelligence to achieve the same goal. In particular we propose to augment the routing layer with the notion of services, so to rely on the robustness and scalability of Interior Gateway Protocols (IGP). Our solution leverages on existing distributed routing protocols where, in addition, autonomous nodes announce information about the virtual services they provide. Our design is modular and incrementally deployable and has been implemented in what we call a NFV Router. In our evaluation, we show that (i) NFV Routers distributed chaining decisions are close to optimal centrally-computed paths, (ii) on a large scale testbed deployment, NFV Routers efficiently steer traffic through chains and only add a small overhead to control traffic and (iii) our distributed system, because of its local control loop, has a faster reaction to network events than centralized solutions.

A Python Toolbox for Processing Air Traffic Data: A Use Case with Trajectory Clustering

Scipedia content — Thu, 28 Jan 2021 18:36:22 +0100

International audience; Problems tackled by researchers and data scientists in aviation and air traffic management (ATM) require manipulating large amounts of data representing trajectories, flight parameters and geographical descriptions of the airspace they fly through. The traffic library for the Python programming language defines an interface to usual processing and data analysis methods to be applied on aircraft trajectories and airspaces. This paper presents how traffic accesses different sources of data, leverages processing methods to clean, filter, clip or resample trajectories, and compares trajectory clustering methods on a sample dataset of trajectories above Switzerland.

Multi-objective zoning for biodiversity and aquaculture in the Adriatic-Ionian region

Scipedia content — Thu, 28 Jan 2021 18:34:30 +0100

Spatial decision-support tools can be used for scenario analysis and guide decision-makers towards transparent and knowledge-based spatial planning. Their application for multi-objective zoning in marine socio-ecological systems is beneficial for supporting the on-going Maritime Spatial Planning (MSP) process. We consider the sustainable development of aquaculture as one of the main maritime activities for sustainable Blue Growth in the Adriatic Ionian Region. The objective of this research is to conceptualize a strategic multi-objective zoning process for aquaculture expansion and biodiversity protection (seabed habitats, marine mammals, seabirds and turtles species distribution, nursery and spawning areas of commercially important fish species) in the Emilia Romagna Region (Italian Northern Adriatic Sea). This area is characterized by the highest productivity of mussels in Italy and is also intensively used by several maritime industries. The projected growth of the Blue Economy is likely to result in an increase of conflicts and impacts on sensitive environments. The decision support tools Marxan and Marxan with Zones are applied to develop alternative planning scenarios and compare solutions in terms of potential impacts on human activities. To do so, we i) build an aquaculture suitability distribution for important commercial species using a multi-criteria analysis that considers environmental, biological and socio-economic factors; ii) prioritize biodiversity using Marxan, while testing how different considerations of human impacts influences priorities (e.g. minimizing the area, number of maritime activities, distance from ports, aquaculture suitability); iii) simultaneously prioritize aquaculture and biodiversity using Marxan with Zones, while minimizing the impact of the number of maritime activities in the Emilia Romagna Region. We compare our scenarios using a novel nearest-neighbour statistical analysis for Marxan’s outputs to understand similarities and differences among scenarios. We conclude that an integrated multi-objective zoning approach, which simultaneously plans for biodiversity and aquaculture, will support more efficient, and therefore more effective strategies for Blue Growth objectives in the AIR.

Renewable Energy Generation and Impacts on E-Mobility

Scipedia content — Thu, 28 Jan 2021 18:30:17 +0100

This paper gives information about Renewable Energy Generation and its impacts on E-Mobility. By 2050, the two pillars of modern transformation are E-Mobility and Renewable Energy. This transformation requires adaptation to meet demographic and economic growth without increasing pollution and congestion. The modern world needs affordable, secure and inclusive, sustainable and integrated with customer-centric infrastructure and services. There is a great fundamental change needed in road transportation sector, which is to achieve its objective of a long term transition to a low-carbon economy. Electric Vehicles when charged with the electricity generated from Renewable Energy Sources can reduce future emissions of greenhouse gases and air pollutants from road transport. Electric Vehicles combined with renewable energy paint a different picture from the oversimplification of gas miles versus electric miles.Smart Mobility and Smart Grid technologies make people live more sustainable and efficiently.

On the Design and Architecture of Deployment Pipelines in Cloud and Service-Based Computing – A Model-Based Qualitative Study

Scipedia content — Thu, 28 Jan 2021 18:29:27 +0100

DevOps and Continuous Delivery (CD) are becoming the de-facto standard for software deployment in the cloud. Deployment pipelines are a core artefact in such practices, but so far their design is largely discussed informally, and existing sources on DevOps and CD practices are often inconsistent or incomplete. The lack of a generic, complete, tool-agnostic, and application-independent treatment of deployment pipeline design and architecture impedes their understanding by human designers and the creation of generic tools that work across different technologies and applications. To alleviate this problem, we have performed a qualitative, in-depth study of 25 deployment practice descriptions by practitioners containing informal deployment pipeline models. From our study we derived a precisely specified model of deployment pipeline architectures. We can show that the formal model substantially increases the precision of the modelling compared to the informally modelled pipelines in the original sources.

Document type: Conference object

Destination-aware Adaptive Traffic Flow Rule Aggregation in Software-Defined Networks

Scipedia content — Thu, 28 Jan 2021 18:26:56 +0100

In this paper, we propose a destination-aware adaptive traffic flow rule aggregation (DATA) mechanism for facilitating traffic flow monitoring in SDN-based networks. This method adapts the number of flow table entries in SDN switches according to the level of detail of traffic flow information that other mechanisms (e.g. for traffic engineering, traffic monitoring, intrusion detection) require. It also prevents performance degradation of the SDN switches by keeping the number of flow table entries well below a critical level. This level is not preset as a hard threshold but learned during operation by using a machine-learning based algorithm. The DATA method is implemented within a RESTful application (DATA App) which monitors and analyzes the ongoing network traffic and provides instructions to the SDN controller to adapt the traffic flow matching strategies accordingly. A thorough performance evaluation of DATA is conducted in an SDN emulation environment. The results show that---compared to the default behavior of common SDN controllers---the proposed DATA approach yields significant SDN switch performance improvements while still providing detailed traffic flow information on demand.

Comment: This paper was presented at NetSys conference 2019. arXiv admin note: text overlap with arXiv:1909.01544

Rain erosivity map for Germany derived from contiguous radar rain data

Scipedia content — Thu, 28 Jan 2021 18:25:01 +0100

Erosive rainfall varies pronouncedly in time and space. Severe events are often restricted to a few square kilometers. Radar rain data with high spatiotemporal resolution enable this pattern of erosivity to be portrayed with high detail. We used radar data with a spatial resolution of 1 km"span class="inline-formula"""sup"2"/sup""/span" over 452 503 km"span class="inline-formula"""sup"2"/sup""/span" to derive a new erosivity map for Germany and to analyze the seasonal distribution of erosivity. The expected long-term regional pattern was extracted from the scattered pattern of events by several steps of smoothing. This included averaging erosivity from 2001 to 2017 and smoothing in time and space. The pattern of the resulting map was predominantly shaped by orography. It generally agrees well with the erosivity map currently used in Germany (Sauerborn map), which is based on regressions using rain gauge data (mainly from the 1960s to 1980s). In some regions the patterns of both maps deviate because the regressions of the Sauerborn map were weak. Most importantly, the new map shows that erosivity is about 66 % larger than in the Sauerborn map. This increase in erosivity was confirmed by long-term data from rain gauge stations that were used for the Sauerborn map and which are still in operation. The change was thus not caused by using a different methodology but by climate change since the 1970s. Furthermore, the seasonal distribution of erosivity shows a slight shift towards the winter period when soil cover by plants is usually poor. This shift in addition to the increase in erosivity may have caused an increase in erosion for many crops. For example, predicted soil erosion for winter wheat is now about 4 times larger than in the 1970s. These highly resolved topical erosivity data will thus have definite consequences for agricultural advisory services, landscape planning and even political decisions.

Document type: Article

Towards Robust Deep Reinforcement Learning for Traffic Signal Control: Demand Surges, Incidents and Sensor Failures

Scipedia content — Thu, 28 Jan 2021 18:05:51 +0100

Reinforcement learning (RL) constitutes a promising solution for alleviating the problem of traffic congestion. In particular, deep RL algorithms have been shown to produce adaptive traffic signal controllers that outperform conventional systems. However, in order to be reliable in highly dynamic urban areas, such controllers need to be robust with the respect to a series of exogenous sources of uncertainty. In this paper, we develop an open-source callback-based framework for promoting the flexible evaluation of different deep RL configurations under a traffic simulation environment. With this framework, we investigate how deep RL-based adaptive traffic controllers perform under different scenarios, namely under demand surges caused by special events, capacity reductions from incidents and sensor failures. We extract several key insights for the development of robust deep RL algorithms for traffic control and propose concrete designs to mitigate the impact of the considered exogenous uncertainties.

Comment: 8 page

Ensuring effectiveness in handling the movement of goods and passengers by enhancing information and communication technologies

Scipedia content — Thu, 28 Jan 2021 18:05:25 +0100

The purpose of this paper is to propose measures for maximum practicable use of information and communication technologies in Ukraine while on cross-border movement of goods and means of transport. For today Ukraine has been intensively implementing the Single Window system, almost completely switched to electronic declaration as well as electronic submission of the documents and information required for official controls of goods belonging to entities or self-employed persons. A passenger declaration, filled out in advance and sent to customs authorities, for goods in accompanied/unaccompanied baggage or freight shipment can also significantly simplify procedures at a border crossing. The effectiveness of the measures proposed is proved using system analysis of well-structured problem by applying critical path method in a PERT diagram and Monte Carlo method for determining optimal time characteristics of handlings. Modeling alternative sequence scenarios of the process of customs clearance at the customs offices of departure and destination allows determining additive components of the total delivery time within customs territory of Ukraine. The scenarios include improvements in Single Window system, establishment of information and communication system for e-declaration of natural persons’ goods and currency valuables. In this regard, first and foremost, experience of different countries on these issues as well as organisational, legal and technical difficulties are analyzed, and then directions for the development are outlined using mini-Delphi approach. In summary, the theoretical relevance of the research lies in the development of the mathematical model for the processes described, practical application of the improvements will reduce delays and additional delivery costs.

HMAPs - Hybrid Height- Voxel Maps for Environment Representation

Scipedia content — Thu, 28 Jan 2021 18:02:48 +0100

This paper presents a hybrid 3D-like grid-based mapping approach, that we called HMAP, used as a reliable and efficient 3D representation of the environment surrounding a mobile robot. Considering 3D point-clouds as input data, the proposed mapping approach addresses the representation of height-voxel (HVoxel) elements inside the HMAP, where free and occupied space is modeled through HVoxels, resulting in a reliable method for 3D representation. The proposed method corrects some of the problems inherent to the representation of complex environments based on 2D and 2.5D representations, while keeping an updated grid representation. Additionally, we also propose a complete pipeline for SLAM based on HMAPs. Indoor and outdoor experiments were carried out to validate the proposed representation using data from a Microsoft Kinect One (indoor) and a Velodyne VLP-16 LiDAR (outdoor). The obtained results show that HMAPs can provide a more detailed view of complex elements in a scene when compared to a classic 2.5D representation. Moreover, validation of the proposed SLAM approach was carried out in an outdoor dataset with promising results, which lay a foundation for further research in the topic.

Detecting ADS-B Spoofing Attacks Using Deep Neural Networks

Scipedia content — Thu, 28 Jan 2021 17:52:20 +0100

The Automatic Dependent Surveillance-Broadcast (ADS-B) system is a key component of the Next Generation Air Transportation System (NextGen) that manages the increasingly congested airspace. It provides accurate aircraft localization and efficient air traffic management and also improves the safety of billions of current and future passengers. While the benefits of ADS-B are well known, the lack of basic security measures like encryption and authentication introduces various exploitable security vulnerabilities. One practical threat is the ADS-B spoofing attack that targets the ADS-B ground station, in which the ground-based or aircraft-based attacker manipulates the International Civil Aviation Organization (ICAO) address (a unique identifier for each aircraft) in the ADS-B messages to fake the appearance of non-existent aircraft or masquerade as a trusted aircraft. As a result, this attack can confuse the pilots or the air traffic control personnel and cause dangerous maneuvers. In this paper, we introduce SODA - a two-stage Deep Neural Network (DNN)-based spoofing detector for ADS-B that consists of a message classifier and an aircraft classifier. It allows a ground station to examine each incoming message based on the PHY-layer features (e.g., IQ samples and phases) and flag suspicious messages. Our experimental results show that SODA detects ground-based spoofing attacks with a probability of 99.34%, while having a very small false alarm rate (i.e., 0.43%). It outperforms other machine learning techniques such as XGBoost, Logistic Regression, and Support Vector Machine. It further identifies individual aircraft with an average F-score of 96.68% and an accuracy of 96.66%, with a significant improvement over the state-of-the-art detector.

Comment: Accepted to IEEE CNS 2019

Yara pipeline transportation of thickened tailings

Scipedia content — Thu, 28 Jan 2021 17:51:33 +0100

Yara has operated the Siilinjarvi mine in Finland since 1979. Each year, the mine produces around 1 M t of apatite concentrate from 11 M t ore, and it is Western Europe’s only phosphate mine. The concentrate is processed into phosphoric acid in Siilinjarvi and then further into fertilisers and feed phosphates in Yara’s plants in Finland and Norway. The tailings have to be deposited at the Siilinjarvi plant, and the existing tailings storage facility (TSF) was reaching full capacity. Yara did an extensive study for future storage of tailings and decided to adopt a thickened tailings solution. The tailings would be thickened to 68–72% by weight in order to build a +2° sloped deposit, thereby sufficiently increasing the storage capacity. Weir Minerals supported Yara from the pilot plant operation, continuing in the sizing of the full plant pumping system until execution and commissioning of the paste pumping plant. After evaluation of the pilot plant results, it was concluded that additional loop testing was required in order to determine the pressure gradients for the full plant pumping system. During project execution, Weir Minerals supplied a complete pumping solution to Yara, comprising of three GEHO® TZPM 2000 pumps and Warman® AH® 10/8F centrifugal pumps. In addition, Weir Minerals supplied the required Isogate® hydraulic-actuated slurry valves, suction strainers, slurry instrumentation and developed the functional description for Yara’s distributed control system (DCS). The system is operated remotely from the plant DCS without any programmable local control (PLC) devices to enable future unmanned, automated operation of the complete pump station. Local control can be established through tablets which are connected to the DCS, providing diagnostic performance reviews of the pump and plant operation. The system was successfully commissioned in February 2017, with slurry solids concentrations reaching planned targets, resulting in a slope at the TSF of approximately 3°. This paper describes the development of the project from the feasibility to the commissioning stage, highlights the main challenges and reflects Yara’s future expectations for plant development and operations at the Siilinjarvi mine.

Make the most out of your SIMD investments: counter control flow divergence in compiled query pipelines

Scipedia content — Thu, 28 Jan 2021 17:48:17 +0100

Increasing single instruction multiple data (SIMD) capabilities in modern hardware allows for the compilation of data-parallel query pipelines. This means GPU-alike challenges arise: control flow divergence causes the underutilization of vector-processing units. In this paper, we present efficient algorithms for the AVX-512 architecture to address this issue. These algorithms allow for the fine-grained assignment of new tuples to idle SIMD lanes. Furthermore, we present strategies for their integration with compiled query pipelines so that tuples are never evicted from registers. We evaluate our approach with three query types: (i) a table scan query based on TPC-H Query 1, that performs up to 34% faster when addressing underutilization, (ii) a hashjoin query, where we observe up to 25% higher performance, and (iii) an approximate geospatial join query, which shows performance improvements of up to 30%.

Document type: Conference object

A Performance Comparison of Dask and Apache Spark for Data-Intensive Neuroimaging Pipelines

Scipedia content — Thu, 28 Jan 2021 17:45:28 +0100

In the past few years, neuroimaging has entered the Big Data era due to the joint increase in image resolution, data sharing, and study sizes. However, no particular Big Data engines have emerged in this field, and several alternatives remain available. We compare two popular Big Data engines with Python APIs, Apache Spark and Dask, for their runtime performance in processing neuroimaging pipelines. Our evaluation uses two synthetic pipelines processing the 81GB BigBrain image, and a real pipeline processing anatomical data from more than 1,000 subjects. We benchmark these pipelines using various combinations of task durations, data sizes, and numbers of workers, deployed on an 8-node (8 cores ea.) compute cluster in Compute Canada's Arbutus cloud. We evaluate PySpark's RDD API against Dask's Bag, Delayed and Futures. Results show that despite slight differences between Spark and Dask, both engines perform comparably. However, Dask pipelines risk being limited by Python's GIL depending on task type and cluster configuration. In all cases, the major limiting factor was data transfer. While either engine is suitable for neuroimaging pipelines, more effort needs to be placed in reducing data transfer time.

Comment: 10 pages, 15 figures, 1 tables. To appear in the proceeding of the 14th WORKS Workshop on Topics in Workflows in Support of Large-Scale Science, 17 November 2019, Denver, CO, USA

Leveraging Vision Reconstruction Pipelines for Satellite Imagery

Scipedia content — Thu, 28 Jan 2021 17:42:34 +0100

Reconstructing 3D geometry from satellite imagery is an important topic of research. However, disparities exist between how this 3D reconstruction problem is handled in the remote sensing context and how multi-view reconstruction pipelines have been developed in the computer vision community. In this paper, we explore whether state-of-the-art reconstruction pipelines from the vision community can be applied to the satellite imagery. Along the way, we address several challenges adapting vision-based structure from motion and multi-view stereo methods. We show that vision pipelines can offer competitive speed and accuracy in the satellite context.

Comment: Project Page: https://kai-46.github.io/VisS

Capacity Subscription Tariffs for Electricity Distribution Networks: Design Choices and Congestion Management

Scipedia content — Thu, 28 Jan 2021 17:40:18 +0100

Residential distribution networks in Europe are undergoing rapid changes. As high-power flexible loads, such as electric vehicle (EV) chargers, become more prevalent, the risk of network congestion increases. This is exacerbated by tariff structures which do not give incentives to limit simultaneous power consumption. Network charges in this case may not reflect the true costs of usage, as network costs are driven mainly by simultaneous load peaks.We present a systematic assessment of a new class of tariffs that is currently gaining attention in the Netherlands: capacity subscription models. We argue that this tariff structure is more cost-reflective and fair than the current fixed network fee and show how it helps to prevent transformer overloading in a simple simulation model of a neighborhood of 100 households constrained by a LV transformer, where a varying number of EVs are added.

Comparative study of level-of-service determination based on VISSIM software and Highway Capacity Manual as exemplified by T-shape and partial cloverleaf interchanges

Scipedia content — Thu, 28 Jan 2021 17:29:39 +0100

This paper presents a comparative analysis of the level-of-service (LOS) determination based on the VISSIM simulation software and technique described in Highway Capacity Manual (HCM). The methodology used in the analysis is that of the level of service determination for road transport network as exemplified by T-shape intersection and partial cloverleaf (parclo AB3) interchange in the city of Kryvyi Rih. The Department of Road Safety of the National Patrol Police of Ukraine set the task to determine the vehicles queuing length on the bridge if traffic lights at the T-shape intersection are installed. To conduct the project, the VISSIM simulation model of the intersection was developed according to site data collection on workdays and at weekends. LOS criteria were determined by using both traffic management assessment methods. The scenario of traffic lights installation at the intersection was elaborated. It was determined that with traffic signalization adjustment the average travel speed would be about 40% of the free flow speed for a street class. The two assessment methods vary significantly regarding traffic flow density criterion (35.1%). The conclusion is that flow density criterion is not reliable for the node LOS definition. By way of application value of the research findings the recommendations have been prepared for T-shape intersection traffic management that dismissing the project of traffic lights installation at the intersection needs to be considered.

Comparing Energy Efficiency of CPU, GPU and FPGA Implementations for Vision Kernels

Scipedia content — Thu, 28 Jan 2021 17:28:46 +0100

Developing high performance embedded vision applications requires balancing run-time performance with energy constraints. Given the mix of hardware accelerators that exist for embedded computer vision (e.g. multi-core CPUs, GPUs, and FPGAs), and their associated vendor optimized vision libraries, it becomes a challenge for developers to navigate this fragmented solution space. To aid with determining which embedded platform is most suitable for their application, we conduct a comprehensive benchmark of the run-time performance and energy efficiency of a wide range of vision kernels. We discuss rationales for why a given underlying hardware architecture innately performs well or poorly based on the characteristics of a range of vision kernel categories. Specifically, our study is performed for three commonly used HW accelerators for embedded vision applications: ARM57 CPU, Jetson TX2 GPU and ZCU102 FPGA, using their vendor optimized vision libraries: OpenCV, VisionWorks and xfOpenCV. Our results show that the GPU achieves an energy/frame reduction ratio of 1.1-3.2x compared to the others for simple kernels. While for more complicated kernels and complete vision pipelines, the FPGA outperforms the others with energy/frame reduction ratios of 1.2-22.3x. It is also observed that the FPGA performs increasingly better as a vision application's pipeline complexity grows.

Comment: 8 pages, Design Automation Conference (DAC), The 15th IEEE International Conference on Embedded Software and Systems, 2019

CONFERENCE PAPERS Year 2 (5/2018 to 10/2018)

Scipedia content — Thu, 28 Jan 2021 17:28:17 +0100

ong"Year 2 (5/2018 to 10/2018) Conference Papers from the University Transportation Center for Underground Transportation Infrastructure (UTC-UTI)."/strong

Machine Learning at Microsoft with ML .NET

Scipedia content — Thu, 28 Jan 2021 17:28:00 +0100

Machine Learning is transitioning from an art and science into a technology available to every developer. In the near future, every application on every platform will incorporate trained models to encode data-based decisions that would be impossible for developers to author. This presents a significant engineering challenge, since currently data science and modeling are largely decoupled from standard software development processes. This separation makes incorporating machine learning capabilities inside applications unnecessarily costly and difficult, and furthermore discourage developers from embracing ML in first place. In this paper we present ML .NET, a framework developed at Microsoft over the last decade in response to the challenge of making it easy to ship machine learning models in large software applications. We present its architecture, and illuminate the application demands that shaped it. Specifically, we introduce DataView, the core data abstraction of ML .NET which allows it to capture full predictive pipelines efficiently and consistently across training and inference lifecycles. We close the paper with a surprisingly favorable performance study of ML .NET compared to more recent entrants, and a discussion of some lessons learned.

Scalable Electric-Motor-in-the-Loop Testing for Vehicle Powertrains

Scipedia content — Thu, 28 Jan 2021 17:26:47 +0100

Model-Based System Testing (MBST) combines physical testing and simulation models to enable the validation of complex systems early-on in their design cycle. Therefore, it shows great potential for the validation of increasingly complex Electric Vehicle (EV) powertrains. In this work, the MBST methodology is applied to a downscaled powertrain, including a Permanent-Magnet Synchronous Machine (PMSM) and a 3-phase switch-mode inverter. This System-under-Test (SuT) is integrated into an X-in-the-Loop (XiL) test bench, where real-time simulation models of the rest of the vehicle are used to impose realistic boundary conditions to the SuT. These include the emulation of the vehicle inertia, its friction losses and the regenerative braking controller. Both hardware and software architectures required to achieve this setup are presented. Subsequently, a methodology used for computing scaling factors that match the power levels of the full vehicle to the miniature test bench is proposed. Finally, the combined physical-virtual system is evaluated on a driving cycle to validate its behaviour. The usage of a downscaled SuT constitutes the first step towards full-scale E-powertrain-in-the-loop testing, as well as a valuable multi-purpose didactical XiL setup.

info:eu-repo/semantics/published

TripAware

Scipedia content — Thu, 28 Jan 2021 17:18:24 +0100

To combat climate change, we need to change user transportation behavior to be less carbon intensive. Prior work on motivating this behavior change has been predominantly qualitative and lacks comparison. This makes it challenging to determine which interventions should be deployed at scale. The behavior change community needs a process to compare interventions against each other in pilot studies before committing deployment resources. We perform the first quantitative comparison, to our knowledge, of behavior change strategies in the transportation behavior domain. Since this is a pilot with a limited recruitment budget, we design a Randomized Controlled Trial (RCT) using an open source platform. We assign 41 users to three mobile applications: Emotion, Information, Control. The RCT allows us to draw statistically valid inferences that can suggest future avenues for larger-scale studies. We found that Emotion resulted in greater engagement with the application (p=0.006, 0.035, 0.031, 0.040) while Information improved the sustainability of travel behavior (p = 0.043). These exploratory statistical results can motivate the design of future studies to further explore combinations of these approaches for sustainable transportation behavior.

Carbon footprint and water footprint of electric vehicles and batteries charging in view of various sources of power supply in the Czech Republic

Scipedia content — Thu, 28 Jan 2021 17:16:27 +0100

In the light of recent developments regarding electric vehicle market share, we assess the carbon footprint and water footprint of electric vehicles and provide a comparative analysis of energy use from the grid to charge electric vehicle batteries in the Czech Republic. The analysis builds on the electricity generation forecast for the Czech Republic for 2015&ndash

2050. The impact of different sources of electricity supply on carbon and water footprints were analyzed based on electricity generation by source for the period. Within the Life Cycle Assessment (LCA), the carbon footprint was calculated using the Intergovernmental Panel on Climate Change (IPCC) method, while the water footprint was determined by the Water Scarcity method. The computational LCA model was provided by the SimaPro v. 8.5 package with the Ecoinvent v. 3 database. The functional unit of study was running an electric vehicle over 100 km. The system boundary covered an electric vehicle life cycle from cradle to grave. For the analysis, we chose a vehicle powered by a lithium-ion battery with assumed consumption 19.9 kWh/100 km. The results show that electricity generated to charge electric vehicle batteries is the main determinant of carbon and water footprints related to electric vehicles in the Czech Republic. Another important factor is passenger car production. Nuclear power is the main determinant of the water footprint for the current and future electric vehicle charging, while, currently, lignite and hard coal are the main determinants of carbon footprint.

Document type: Article

Integrated System for Traction and Battery Charging of Electric Vehicles with Universal Interface to the Power Grid

Scipedia content — Thu, 28 Jan 2021 17:12:58 +0100

This paper proposes an integrated system for traction and battery charging of electric vehicles (EVs) with universal interface to the power grid. In the proposed system, the power electronics converters comprising the traction drive system are also used for the battery charging system, reducing the required hardware, meaning the integrated characteristic of the system. Besides, this interface is universal, since it can be performed with the three main types of power grids, namely: (1) Single-phase AC power grids; (2) Three-phase AC power grids; (3) DC power grids. In these three types of interfaces with the power grid, as well as in the traction drive operation mode, bidirectional operation is possible, framing the integration of this system into an EV in the context of smart grids. Moreover, the proposed system endows an EV with an on-board fast battery charger, whose operation allows either fast or slow battery charging. The main contributes of the proposed system are detailed in the paper, and simulation results are presented in order to attain the feasibility of the proposed system. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT -Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work has been supported by FCT within the Project Scope DAIPESEV - Development of Advanced Integrated Power Electronic Systems for Electric Vehicles: PTDC/EEI-EEE/30382/2017. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283.

Document type: Conference object

Air traffic deconfliction using sum coloring

Scipedia content — Thu, 28 Jan 2021 17:10:07 +0100

Best of Session (UTM-6: sUAS Traffic Management and Deconfliction) Award, 38 DASC 38th IEEE/AIAA Digital Avionics Systems Conference

This paper studies strategic conflict resolution for air traffic based on sum coloring. We consider two application scenarios: manned and unmanned air traffic, with similar targets: to improve efficiency of operations and to reduce the costs. For the Unmanned Air Vehicles Traffic Management (UTM) we consider also a payment mechanism which incentivizes the operators to share information necessary to find a socially optimal solution. We quantify the potential savings via a series of experiments, showing that our methods drastically outperform the widely used First-Come-First-Serve (FCFS) strategy.

Peer Reviewed

Award-winning

Efficiency of managing the production capacity of service enterprises, taking into account customer motivation

Scipedia content — Thu, 28 Jan 2021 17:09:28 +0100

This paper presents a methodology that has been developed for analyzing the production activities of posts, which allows to identify customers by their categories and territorial "affections", the emergence of which should be activated by a specific service enterprise. An algorithm has been developed for finding solutions for improving the quality of services and customer service conditions for a car service center. The practical implementation of the methodology was carried out on the basis of existing service enterprises for servicing trucks. Measures were found to increase the capacity of the production of service enterprises, which allows a particular enterprise to maintain its economic stability in a competitive environment. The criteria reflecting the production activities of the auto service enterprise are selected in accordance with justified principles. It is established that regular customers who apply for services more than three times, bring more revenue.

User expectations and implications for designing the user experience of shared vehicles

Scipedia content — Thu, 28 Jan 2021 17:08:08 +0100

Shared mobility is one of the main focus of mobility companies and start-ups in recent years. Despite the fact that many cities have some form of shared vehicles, it is still a niche market with the potential to become a sustainable business. In this paper, we investigate the limitations and possibilities of shared vehicles to make them more appealing to users. A combination of a literature survey, online survey, and interviewing individuals and stakeholders provide directions for future solutions. Our findings reveal that current shared vehicles services are at the beginning, where stakeholders focus on developing frameworks and regulations to deploy current services. However, the future of shared vehicles lies in the experiences provided in and around the vehicle, which might result in the development of new and more specific vehicles for certain users and contexts. The outcome is an invitation to discover and discuss the experiences of shared vehicles.

Traffic Safety Subsystem Management at Enterprises Engaged in Road Transport Activities

Scipedia content — Thu, 28 Jan 2021 17:04:56 +0100

Information Technology of Surveys and Diagnostics of Underground Pipelines

Scipedia content — Thu, 28 Jan 2021 16:59:43 +0100

ong"Dzhala R., Dzhala V., Horon B., Senyuk O., Verbenets’ B. Information Technology of Surveys and Diagnostics of Underground Pipelines // 2019 XIth International Scientific and Practical Conference on Electronics and Information Technologies (ELIT), September 16–18, 2019, Lviv, Ukraine. P. 214–218."/strong" The problems of inspections, nondestructive testing, and diagnostics of underground pipelines from the standpoint of the structure and functioning of modern cyber-physical systems are discussed. Method and apparatus for contactless measurement of currents with memory and automatic computer processing of results improve efficiency and information of testing to ensure the reliability and extension of trouble-free operation of pipelines.

Document type: Conference object

Deep Learning-Based Real-Time Object Detection in Inland Navigation

Scipedia content — Thu, 28 Jan 2021 16:58:52 +0100

International audience; Semi-autonomous and fully-autonomous systems must have knowledge about the objects in their environment to ensure a safe navigation. Modern approaches implement deep learning techniques to train a neural network for object detection. This project will study the effectiveness of using several promising algorithms such as Faster R-CNN, SSD, and different versions of YOLO, to detect, classify, and track objects in near real-time fluvial domain. Since no dataset is available for this purpose in literature, we first started by annotating a dataset of 2488 images with almost 35 400 annotations for training the convolutional neural network architectures. We made this data set openly accessible for the community working on this area. The other contribution of this research is the adaptation and the configuration of deep learning techniques used in other domains such as maritime and road domain to fluvial domain for autonomous vessels in which high accuracy and fast processing are vital. Experiments demonstrated that detecting objects in such environment is plausible in near real time with the selected algorithms.

Use of traffic calming measures in the Republic of Belarus

Scipedia content — Thu, 28 Jan 2021 16:58:37 +0100

Traffic calming is one of the main approaches to ensuring safety in city streets and it is based on the concept of speed containment. The aim of this approach is to minimize passing transit flows through the streets of district importance, to ensure the safety of pedestrians and cyclists, as well as to impact the behavior of drivers in urban conditions. City streets should be designed taking into account the restriction of "extra" speed, in accordance with the category and purpose. It is necessary to have regard to the functionality of the street, the uniformity of the traffic flow, the appropriateness of the imposed limitations, and the predictability of the technical means used to organize traffic. The main criteria for the use of traffic calming measures can be: accident rate, speed through traffic, and specific traffic conditions. The article presents practical results of studies on traffic conditions in the pedestrian crossings areas equipped with humps. It discusses alternative measures of physical and psychological effects on the traffic participants in the context of the traffic calming approach.

Evaluation of the LDACS Cybersecurity Implementation

Scipedia content — Thu, 28 Jan 2021 16:58:03 +0100

Communication, Navigation and Surveillance (CNS) infrastructure in civil aviation must evolve as fast as possible to cope with all challenges posed by the growth of the worldwide population, globalization and the worldwide demand for more and more mobility. Analogue systems are replaced by digital means and automation is becoming much more important to be able to handle the large amount of new entrants in the air traffic system. Spectrum saturation must be solved by introducing digital systems and safety and security of the safety critical infrastructure surrounding civil aviation must be constantly updated to support the ever-growing system complexity. As one of the Future Communication Infrastructure (FCI) candidates we introduce LDACS as the very first true integrated CNS system worldwide. In previous works we have already analyzed its cybersecurity, developed a cybersecurity architecture with corresponding algorithms and demonstrated the improvement in cybersecurity due to our security additions. Here we implement the LDACS cybersecurity architecture and evaluate the impact of introduced security overhead on the LDACS system. We conclude that the proposed protection mechanisms successfully mitigate previously identified risks and only add minor time, data and computation overhead on top of the LDACS protocol stack. With this result, the security solutions are a good candidate to be included in the SESAR wave 2 updated LDACS specification.

Market adoption and impact of electric roadwayson criteria pollutants and greenhouse gas emissions

Scipedia content — Tue, 26 Jan 2021 18:27:03 +0100

Traffic is inevitably a major source of air pollution, particularly in urban areas. Efforts are made towards reducing emissions by improving vehicle and fuel technology and promoting alternative, sustainable modes of transportation. Although the emergence of EVs has shown capabilities of decreasing energy use and emissions levels, the EV market is developing slowly mainly due to drivers’ range anxiety and charging time. Electric roadways (ERs) have been proposed as a solution to overcome the concerns related to EVs by converting road segments into powered lanes where vehicles can be charged as they move along the roadway. This technology has the potential to increase driving range, decrease battery size and thus, lower the weight and the cost of EVs. In this context, exploring the challenging concept of ERs comes natural.

Since data on the market acceptance and the environmental implications on this technology are limited to non-existent, this thesis has the following objectives: 1) identify the factors that affect the short- and long-term intention to use ERs, 2) estimate the level of adoption of the ER technology and identify characteristics of the market segments and 3) assess the impact of ERs on criteria pollutants and greenhouse gas emissions based on the market adoption results.

To achieve these objectives, a survey of the general population in Los Angeles, California was conducted, gathering 600 responses representative of gender and age in the area. Los Angeles is considered a leader in electro-mobility and thus, a natural choice for the implementation of ERs. The short-or long-term intentions to drive on ERs and purchase an EV knowing about the availability of ERs were found to be correlated and thus, were modeled simultaneously using a bivariate ordered probit model. The compatibility of the ER technology with respondents’ lifestyle and needs, respondents’ tendency towards using sustainable forms of transportation, respondents’ innovativeness and perceived environmental benefits were among the most significant variables found to affect the short-term and long-term intention to use ERs.

The level of adoption of the ER technology and corresponding market segments were identified using a combination of Principal Component Analysis (PCA) and Cluster Analysis. Three clusters emerged from the analysis: early adopters (48.5%), mid-adopters (27.67%) and late adopters (23.83%) that differed in terms of demographics and socioeconomic characteristics, travel and EV charging characteristics and level of awareness.

The adoption levels found were then used to estimate the emissions change due to the implementation of the ERs by 2050. Using the California Air Resources Board’s (CARB) 2017 EMissions FACtor model (EMFAC). Two scenarios were examined considering light-duty vehicles (LDVs) in a specific corridor: “with” and “without electrification” scenarios. The results suggested that the ER technology for light-duty vehicles has the potential to provide emission reductions of 4 to 24%. A sensitivity analysis was also conducted to examine the effect of speed on the results.

Turning to the practical implications, this thesis can provide a foundational framework for the evaluation of the ER technology in terms of environmental and economic viability and set the groundwork for future research. Ultimately, the short-term and long-term intention analysis can be used as a draft guide by state and local agencies and inform their strategic short- or long- range plans for mobility. By segmenting potential users, policy makers and transport operators can be informed about the main challenges regarding the promotion of the ER technology to distinct market segments and devise ways to accelerate its adoption. The findings from the impact analysis of ERs on criteria pollutants and greenhouse gases can also inform long-range transportation plans and existing regulations and policies in California and beyond.

Analysis of the performance in wireless transmission systems for application in electric vehicles

Scipedia content — Tue, 26 Jan 2021 18:21:02 +0100

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior O objetivo deste trabalho consiste em analisar o comportamento de um sistema de transferência de potência sem fios para aplicações em veículos elétricos, utilizando o princípio do acoplamento magnético. E, para alcança-lo, foi necessário construir um circuito inversor para que a bobina emissora opere em ressonância magnética com a bobina receptora. Foi elaborado uma rotina computacional para calcular o rendimento de um circuito ressonante, a partir dos parâmetros físicos e elétricos das bobinas. O protótipo consiste em energizar uma bobina plana primária e realizar a transferência indutiva para a bobina secundária, podendo ser de mesmo tamanho ou não. Resultados experimentais foram coletados, tais como, curvas de rendimento em função da distância, transferência através de barreiras metálicas e não metálicas, rendimentos em função do desalinhamento entre bobinas, carga em bateria automotiva, distâncias máximas de transferência; dentre outros. Um sistema desse tipo pode trazer muitos benefícios para aplicação no carregamento de baterias em veículos elétricos de forma prática, segura e com rendimentos satisfatórios quando realizado a transferência indutiva sem fios. The objective of this work is to analyze the behavior of a wireless power transfer system for applications in electric vehicles, using the principle of magnetic coupling. And in order to reach it, it was necessary to construct an inverter circuit so that the sending coil operates in magnetic resonance with the receiving coil. A computational routine was developed to calculate the efficiency of a resonant circuit, based on the physical and electrical parameters of the coils. The prototype consists of energizing a primary flat coil and performing the inductive transfer to the secondary coil, which may be the same size or not. Experimental results were collected, such as yield curves as a function of distance, transfer through metallic and non-metallic barriers, yields due to misalignment between coils, automotive battery charge, maximum transfer distances; and others. Such a system can bring many benefits for application in battery charging in electric vehicles in a practical way and with satisfactory yields when conducting wireless inductive transfer. Dissertação (Mestrado)

Escenarios para el cambio de vehículos con motor de combustión interna a vehículos eléctricos en el transporte de carga en Colombia

Scipedia content — Tue, 26 Jan 2021 18:20:33 +0100

¿En qué momento es adecuado adquirir vehículos eléctricos para la operación de transporte de carga en Colombia?, es una pregunta que los encargados de las empresas de transporte en Colombia deben responder para poder seguir funcionando en las actuales y eventuales nuevas regulaciones ambientales aplicadas al transporte de carga. En el presente trabajo se desarrolló un modelo que permite evaluar la factibilidad económica del cambio de vehículos con motor de combustión interna (VCI) a vehículos eléctricos (VE) en el transporte de carga en Colombia, aportando un análisis que permita a las empresas revisar varios escenarios y casos de aplicación. La velocidad del cambio de los VCI por VE en Colombia depende principalmente del comportamiento del costo de fabricación de las baterías, y de las operaciones en las que se desempeñen los vehículos, pues las operaciones en las que el peso no es la restricción más importante presentan una factibilidad económica mejor y más rápida que en las operaciones donde el peso es importante, principalmente porque los VE tienen mayor peso tara que los VCI. Por otro lado, si se colocaran de manera permanente restricciones de circulación de al menos 6 horas a la semana para los VCI, los VE resultarían ser más económicos que los VCI antes del año 2025 para operaciones en las que el peso es la restricción es la más importante Abstract: when is it appropriate to acquire electric vehicles for the cargo transport operation in Colombia? It is a question that the managers of the transportation companies in Colombia must answer to be able to continue operating in the current and possible new environmental regulations applied to cargo transport. In the present work a model was developed that allows to evaluate the economic feasibility of the change of vehicles with internal combustion engine to electric vehicles in cargo transportation in Colombia, providing an analysis that allows companies to review various scenarios and application cases. The speed of the change of vehicles with internal combustion engine for electric vehicles in Colombia depends mainly on the behavior of the cost of manufacturing the batteries, and on the operations in which the vehicles are performed, since the operations in which the weight is not The most important restriction has a better and faster economic feasibility than in operations where the weight is important, because the VE have a greater empty weight than the IVC. On the other hand, if traffic restrictions of at least 6 hours per week for VCIs were permanently placed, VEs would prove to be cheaper than VCIs before the year 2025 for operations in which the weight is the most important restriction.

Data-driven smart mobility as an act to mitigate climate change, a case of Hangzhou

Scipedia content — Tue, 26 Jan 2021 18:17:37 +0100

The transport sector is responsible for a significant and growing proportion of greenhouse gas emissions. The urgent actions are required to take in the transport sector facing the challenge of growing global change. The major trends, including global urbanization, widespread application of digital technologies, and broad demand for sustainable development, have provided new opportunities for data-driven smart mobility in the future. This research aims to explore potentials of data-driven smart mobility in achieving Sustainable Development Goal 11.2, “provide access to safe, affordable, accessible and sustainable transport systems for all,” and Sustainable Development Goal 13.2, “take urgent action to combat climate change and its impacts” and “integrate climate change measures into national policies, strategies and planning” reducing greenhouse gas emissions every year. In order to meet this aim, this research explores the understandings and innovations of data-driven smart mobility in achieving decarbonization in urban, as well as barriers during the current practices. Hangzhou, as the capital city in Zhejiang Province in China, has been selected for the case study to examine data-driven smart mobility approaches. The research results show that the potentials of the data to tackle climate issues lie in the efficient transport operation and travel behaviors change. Data technologies have been widely applied to improve the integration of travel modes and the efficiency of transport management to reduce greenhouse gas emissions in road traffic. However, there are few drivers to mine data resources for travel behavior change. Moreover, data-driven smart mobility initiatives applied in urban areas involve multiple stakeholders but with limited access to data sharing and opening. Considering disruptive effects and potential promises brought by the big data technologies, the implementation of smart mobility requires for public data strategy with a holistic view of the complex urban challenges and global climate change.

Enhancing user experience and safety in the context of automated driving through uncertainty communication

Scipedia content — Tue, 26 Jan 2021 18:15:37 +0100

Operators of highly automated driving systems may exhibit behaviour characteristic of overtrust issues due to an insufficient awareness of automation fallibility. Consequently, situation awareness in critical situations is reduced and safe driving performance following emergency takeovers is impeded. Previous research has indicated that conveying system uncertainties may alleviate these issues. However, existing approaches require drivers to attend the uncertainty information with focal attention, likely resulting in missed changes when engaged in non-driving-related tasks. This research project expands on existing work regarding uncertainty communication in the context of automated driving. Specifically, it aims to investigate the implications of conveying uncertainties under consideration of non-driving-related tasks and, based on the outcomes, develop and evaluate an uncertainty display that enhances both user experience and driving safety. In a first step, the impact of visually conveying uncertainties was investigated under consideration of workload, trust, monitoring behaviour, non-driving-related tasks, takeover performance, and situation awareness. For this, an anthropomorphic visual uncertainty display located in the instrument cluster was developed. While the hypothesised benefits for trust calibration and situation awareness were confirmed, the results indicate that visually conveying uncertainties leads to an increased perceived effort due to a higher frequency of monitoring glances. Building on these findings, peripheral awareness displays were explored as a means for conveying uncertainties without the need for focused attention to reduce monitoring glances. As a prerequisite for developing such a display, a systematic literature review was conducted to identify evaluation methods and criteria, which were then coerced into a comprehensive framework. Grounded in this framework, a peripheral awareness display for uncertainty communication was developed and subsequently compared with the initially proposed visual anthropomorphic uncertainty display in a driving simulator study. Eye tracking and subjective workload data indicate that the peripheral awareness display reduces the monitoring effort relative to the visual display, while driving performance and trust data highlight that the benefits of uncertainty communication are maintained. Further, this research project addresses the implications of increasing the functional detail of uncertainty information. Results of a driving simulator study indicate that particularly workload should be considered when increasing the functional detail of uncertainty information. Expanding upon this approach, an augmented reality display concept was developed and a set of visual variables was explored in a forced choice sorting task to assess their ordinal characteristics. Particularly changes in colour hue and animation-based variables received high preference ratings and were ordered consistently from low to high uncertainty. This research project has contributed a series of novel insights and ideas to the field of human factors in automated driving. It confirmed that conveying uncertainties improves trust calibration and situation awareness, but highlighted that using a visual display lessens the positive effects. Addressing this shortcoming, a peripheral awareness display was designed applying a dedicated evaluation framework. Compared with the previously employed visual display, it decreased monitoring glances and, consequentially, perceived effort. Further, an augmented reality-based uncertainty display concept was developed to minimise the workload increments associated with increases in the functional detail of uncertainty information.

Graph-based Algorithms for Smart Mobility Planning and Large-scale Network Discovery

Scipedia content — Tue, 26 Jan 2021 18:14:11 +0100

Graph theory has become a hot topic in the past two decades as evidenced by the increasing number of citations in research. Its applications are found in many fields, e.g. database, clustering, routing, etc. In this thesis, two novel graph-based algorithms are presented. The first algorithm finds itself in the thriving carsharing service, while the second algorithm is about large graph discovery to unearth the unknown graph before any analyses can be performed. In the first scenario, the automatisation of the fleet planning process in carsharing is proposed. The proposed work enhances the accuracy of the planning to the next level by taking an advantage of the open data movement such as street networks, building footprints, and demographic data. By using the street network (based on graph), it solves the questionable aspect in many previous works, feasibility as they tended to use rasterisation to simplify the map, but that comes with the price of accuracy and feasibility. A benchmark suite for further research in this problem is also provided. Along with it, two optimisation models with different sets of objectives and contexts are proposed. Through a series of experiment, a novel hybrid metaheuristic algorithm is proposed. The algorithm is called NGAP, which is based on Reference Point based Non-dominated Sorting genetic Algorithm (NSGA-III) and Pareto Local Search (PLS) and a novel problem specific local search operator designed for the fleet placement problem in carsharing called Extensible Neighbourhood Search (ENS). The designed local search operator exploits the graph structure of the street network and utilises the local knowledge to improve the exploration capability. The results show that the proposed hybrid algorithm outperforms the original NSGA-III in convergence under the same execution time. The work in smart mobility is done on city scale graphs which are considered to be medium size. However, the scale of the graphs in other fields in the real-world can be much larger than that which is why the large graph discovery algorithm is proposed as the second algorithm. To elaborate on the definition of large, some examples are required. The internet graph has over 30 billion nodes. Another one is a human brain network contains around 1011 nodes. Apart of the size, there is another aspect in real-world graph and that is the unknown. With the dynamic nature of the real-world graphs, it is almost impossible to have a complete knowledge of the graph to perform an analysis that is why graph traversal is crucial as the preparation process. I propose a novel memoryless chaos-based graph traversal algorithm called Chaotic Traversal (CHAT). CHAT is the first graph traversal algorithm that utilises the chaotic attractor directly. An experiment with two well-known chaotic attractors, Lozi map and Rössler system is conducted. The proposed algorithm is compared against the memoryless state-of-the-art algorithm, Random Walk. The results demonstrate the superior performance in coverage rate over Random Walk on five tested topologies; ring, small world, random, grid and power-law. In summary, the contribution of this research is twofold. Firstly, it contributes to the research society by introducing new study problems and novel approaches to propel the advance of the current state-of-the-art. And Secondly, it demonstrates a strong case for the conversion of research to the industrial sector to solve a real-world problem.

Architecting Safe Automated Driving with Legacy Platforms

Scipedia content — Tue, 26 Jan 2021 18:13:31 +0100

Modern vehicles have electrical architectures whose complexity grows year after year due to feature growth corresponding to customer expectations. The latest of the expectations, automation of the dynamic driving task however, is poised to bring about some of the largest changes seen so far. In one fell swoop, not only does required functionality for automated driving drastically increase the system complexity, it also removes the fall-back of the human driver who is usually relied upon to handle unanticipated failures after the fact. The need to architect thus requires a greater rigour than ever before, to maintain the level of safety that has been associated with the automotive industry. The work that is part of this thesis has been conducted, in close collaboration with our industrial partner Scania CV AB, within the Vinnova FFI funded project ARCHER. This thesis aims to provide a methodology for architecting during the concept phase of development, using industrial practices and principles including those from safety standards such as ISO 26262. The main contributions of the thesis are in two areas. The first area i.e. Part A contributes, (i) an analysis of the challenges of architecting automated driving, and serves as a motivation for the approach taken in the rest of this thesis, i.e. Part B where the contributions include, (ii) a definition of a viewpoint for functional safety according to the definitions of ISO 42010, (iii) a method to systematically extract information from legacy components and (iv) a process to use legacy information and architect in the presence of uncertainty to provide a work product, the Preliminary Architectural Assumptions (PAA), as required by ISO 26262. The contributions of Part B together comprise a methodology to architect the PAA. A significant challenge in working with the industry is finding the right fit between idealized principles and practical utility. The methodology in Part B has been judged fit for purpose by different parts of the organization at Scania and multiple case studies have been conducted to assess its usefulness in collaboration with senior architects. The methodology was found to be conducive in both, generating the PAA of a quality that was deemed suitable to the organization and, to find inadequacies in the architecture that had not been found earlier using the previous non-systematic methods. The benefits have led to a commissioning of a prototype tool to support the methodology that has begun to be used in projects related to automation at Scania. The methodology will be refined as the projects progress towards completion using the experiences gained. A further impact of the work is seen in two patent filings that have originated from work on the case studies in Part B. Emanating from needs discovered during the application of the methods, these filed patents (with no prior publications) outline the future directions of research into reference architectures augmented with safety policies, that are safe in the presence of detectable faults and failures. To aid verification of these ideas, work has begun on identifying critical scenarios and their elements in automated driving, and a flexible simulation platform is being designed and developed at KTH to test the chosen critical scenarios. Efterfrågan på nya funktioner leder till en ständigt ökande komplexitet i moderna fordon, speciellt i de inbyggda datorsystemen. Införande av autonoma fordon utgör inte bara det mest aktuella exemplet på detta, utan medför också en av de största förändringar som fordonsbranschen sett. Föraren, som ”back-up” för att hantera oväntade situationer och fel, finns inte längre där vid höggradig automation, och motsvarande funktioner måste realiseras i de inbyggda system vilket ger en drastisk komplexitetsökning. Detta ställer systemarkitekter för stora utmaningar för att se till att nuvarande nivå av funktionssäkerhet bibehålls. Detta forskningsarbete har utförts i nära samarbete med Scania CV AB i det Vinnova (FFI)-finansierade projektet ARCHER. Denna licentiatavhandling har som mål att ta fram en metodik för konceptutveckling av arkitekturer, förankrat i industriell praxis och principer, omfattande bl.a. de som beskrivs i funktionssäkerhetsstandards som ISO 26262. Avhandlingen presenterar resultat inom två områden. Det första området, del A, redovisar, (i) en analys av utmaningar inom arkitekturutveckling för autonoma fordon, vilket också ger en motivering för resterande del av avhandlingen. Det andra området, del B, redovisar, (ii) en definition av en ”perspektivmodell” (en s.k. ”viewpoint” enligt ISO 42010) för funktionssäkerhet, (iii) en metod för att systematiskt utvinna information från existerande komponenter, och (iv) en process som tar fram en arbetsprodukt för ISO 26262 – Preliminära Arkitektur-Antaganden (PAA). Denna process använder sig av information från existerande komponenter – resultat (iii) och förenklar hantering av avsaknad/osäker information under arkitekturarbetet. Resultaten från del B utgör tillsammans en metodik för att ta fram en PAA. En utmaning i forskning är att finna en balans mellan idealisering och praktisk tillämpbarhet. Metodiken i del B har utvärderats i flertalet industriella fallstudier på Scania i samverkan med seniora arkitekter från industrin, och har av dessa bedömts som relevant och praktiskt tillämpningsbar. Erfarenheterna visar att metodiken stödjer framtagandet av PAA’s av lämplig kvalitet och ger ett systematiskt sätt att hantera osäkerhet under arkitekturutvecklingen. Specifikt så gjorde metoden det möjligt att identifiera komponent-felmoder där arkitekturen inte var tillräcklig för åstadkomma önskad riskreducering, begränsningar som inte hade upptäckts med tidigare metoder. Ett prototypverktyg för att stödja metodiken har utvecklats och börjat användas på Scania i projekt relaterade till autonoma fordon. Metodiken kommer sannolikt att kunna förfinas ytterligare när dessa projekt går mot sitt slut och mer erfarenheter finns tillgängliga. Arbetet i del B har vidare lett till två patentansökningar avseende koncept som framkommit genom fallstudierna. Dessa koncept relaterar till referensarkitekturer som utökats med policies för personsäkerhet (Eng. ”safety”) för att hantera detekterbara felfall, och pekar ut en riktning för framtida forskning. För att stödja verifiering av dessa koncept har arbete inletts för att identifiera kritiska scenarios för autonom körning. En flexibel simuleringsplattform håller också på att designas för att kunna testa kritiska scenarios. Vinnova-FFI funded Project ARCHER

Passenger Influence on Dwell Time : A Case Study on the Light Rail Transit Line Tvärbanan in Stockholm

Scipedia content — Tue, 26 Jan 2021 18:09:32 +0100

This thesis conducts research on the light rail transit (LRT)-line Tvärbanan in Stockholm regarding punctuality of dwell time (DT), focusing on the influence passengers have on the mean and the variance of DT. The eight major stops during rush-hours are analyzed through a combination of quantitative and qualitative analysis. DT is proved to be affected by many factors in a complex setting, with vast differences between stops and between train types, proving that the infrastructure, the platform design, and the train design is important factors. The overall core problem is the non-uniformity of passengers, which is caused mainly by (1) the platform layout, especially the locations of entrances/exits, (2) placement of the train doors in relation to platform obstacles, (3) connections to other means of public transportation, and (4) the overall placement of the entrances/exits at other stops in the same direction. Stop-specific measures and suggestions of overall improvements are proposed in order to reduce the mean and the variation of DT. Detta examensarbete undersöker hur uppehållstid påverkas av passagerare på light rail-linjen Tvärbanan i Stockholm, vilket har haft en historia av höga och oförutsägbara uppehållstider. De åtta största hållplatserna under rusningstid är analyserade genom en kombination av kvalitativa och kvantitativa studier. Uppehållstiden beror på många faktorer i en complex miljö, där stora skillnader finns mellan de olika hållplatserna och de olika tågtyperna, vilket är ett bevis att infrastrukturen, plattformsdesignen och tågdesignen är viktiga faktorer. Grundproblemet är att passagerare är ojämnt fördelade på plattformarna, vilket är orsakat av (1) plattformsdesignen, speciellt vart ingångar/utgångar är placerade, (2) vart tågdörrarna stannar i relation till objekt på plattformen, (3) förbindelser till annan kollektivtrafik och (4) hur ingångar/utgångar är placerade över hela linjen i samma riktning. Övergripande och hållplatsspecifika åtgärder för att minimera uppehållstiden presenteras i rapporten.

Smart cities – smart mobility : the impact of multimodal mobility services in the metropolitan area of Lisbon

Scipedia content — Tue, 26 Jan 2021 18:08:38 +0100

Thesis presented as partial requirement for obtaining the master’s degree in Information Management with specialization in Information Systems and Technologies Management The urbanization phenomenon brings great challenges to the cities and smart city's initiatives, for example smart mobility solutions, are being put in place as a strategy to mitigate the effects. With this study we intend to disclosure the current situation of the metropolitan area of Lisbon regarding smart mobility and multimodal mobility systems: with the development of the present work we gathered examples of smart passenger transport and multimodal solutions, acknowledge the level to which the citizens of the metropolitan area are aware of these solutions and committed to incorporate it in their daily lives and understood how the metropolitan area of Lisbon compares to other European cities regarding smart mobility theme. The methodology adopted was the analysis of an existent European dataset related to the preferences of the European citizens on emerging technology-based passenger transport solutions and the development of a survey custom made to the citizens of the metropolitan area of Lisbon. The results demonstrated the citizens of the metropolitan area of Lisbon are highly unhappy with the available mobility systems and use mainly the private car as transport mode and the importance of multimodal mobility systems were confirmed. O fenómeno da urbanização traz grandes desafios às cidades e as iniciativas de cidades inteligentes, das quais fazem parte as soluções mobilidade inteligente, estão a ser utilizadas como estratégias para mitigar os efeitos deste fenómeno. Com este estudo pretendemos apresentar a situaçã atual da área metropolitana de Lisboa relativamente a mobilidade inteligente e a sistemas de mobilidde multimodal: no decorrer do estudo foram reunidos vários exemplos de soluções inteligentes de transporte de passageiros, foi avaliado o nível de conhecimento dos cidadãos acerca deste tipo de soluções e a sua disponibilidade e compromisso de adopção das mesmas no seu dia-a-dia e foi ainda feita uma comparação do tema da mobilidade inteligente na área metropolitana de Lisboa face outras cidades semelhantes na Europa. A metodologia adoptada passou pela análise de um dataset Europeu relativo às preferências dos cidadãos europeus acerca de soluções inovadoras alanvacadas pelas tecnologias emergentes e pelo desenvolvimento de um questionário para os cidadãos da área metropolitana de Lisboa. Os resultados mostram que existe um descontentamento dos cidadãos da área metropolitana de Lisboa com os sistemas de mobilidade existentes e que o carro pessoal é o meio de transporte mais utilizado; os resultados suportam ainda a importância do tema da mobilidade multimodal para a área metropolitana de Lisboa.

Holistic Temporal Situation Interpretation for Traffic Participant Prediction

Scipedia content — Tue, 26 Jan 2021 18:06:29 +0100

For a profound understanding of traffic situations including a prediction of traf- fic participants’ future motion, behaviors and routes it is crucial to incorporate all available environmental observations. The presence of sensor noise and depen- dency uncertainties, the variety of available sensor data, the complexity of large traffic scenes and the large number of different estimation tasks with diverging requirements require a general method that gives a robust foundation for the de- velopment of estimation applications. In this work, a general description language, called Object-Oriented Factor Graph Modeling Language (OOFGML), is proposed, that unifies formulation of esti- mation tasks from the application-oriented problem description via the choice of variable and probability distribution representation through to the inference method definition in implementation. The different language properties are dis- cussed theoretically using abstract examples. The derivation of explicit application examples is shown for the automated driv- ing domain. A domain-specific ontology is defined which forms the basis for four exemplary applications covering the broad spectrum of estimation tasks in this domain: Basic temporal filtering, ego vehicle localization using advanced interpretations of perceived objects, road layout perception utilizing inter-object dependencies and finally highly integrated route, behavior and motion estima- tion to predict traffic participant’s future actions. All applications are evaluated as proof of concept and provide an example of how their class of estimation tasks can be represented using the proposed language. The language serves as a com- mon basis and opens a new field for further research towards holistic solutions for automated driving.

Models and algorithms for network optimization with segment routing

Scipedia content — Tue, 26 Jan 2021 18:04:21 +0100

Optimizing the way traffic is routed over networks has been of interest since we first started using computer networks to communicate and exchange information. Network technologies are constantly evolving and so do the underlying problems that need to be solved. This thesis focus on studying the recently proposed segment routing technology. In a traditional IP network, packets are routed using shorted paths according to weights that are configured on the network links. Segment routing offers a new way of routing traffic by allowing packets to do some detours on their way. Between these detours, traditional shortest path routing is used, making this technology have almost no usage overhead. We aim at providing a mathematical formalization of segment routing and showcase several of its use cases. We believe that such a formalization is going to help advance the research of the algorithmic aspects of segment routing by providing a solid mathematical foundation and notations which can serve as a starting point for others to research this topic. We leverage segment routing to solve traffic engineering problems, perform network monitoring and provide traffic duplication services that are robust to link failures. (FSA - Sciences de l'ingénieur) -- UCL, 2020

Automation Control of a Point Merge System at Palma de Mallorca Airport

Scipedia content — Tue, 26 Jan 2021 17:57:28 +0100

The main objective of this project is to design an automation control system for a new arrival procedure at Palma de Mallorca airport, which is the Point Merge System (PMS). This new system, suggested by Cercle d’Economia de Mallorca, allows performing Continuous Descent Approach (CDA), reducing fuel consumption, CO2 and acoustic emissions, while safety levels are enhanced and arrival capacity is increased. Additionally, the fact of introducing the automation control would remove the air traffic controllers presence, only needing one person to monitor the system. The PMS concept was developed by Eurocontrol and is based on the merging of two arrival flows in one single entry point, which is afterwards linked to the airport runway. Nowadays, these flows are managed by controllers who give the “direct-to” instruction to pilots to fly towards the merge point, whereas in this project this will be done by the system. In order to achieve the aim of the project, the Network Strategic Tool (NEST) from Eurocontrol has been used, which allows traffic simulations, together with Matlab, in which the NEST files have been read and different time computations have been performed to determine when the aircraft gets the “direct-to” and in this way ensure safety. The obtained results are for two diferent scenarios. On one hand, real traffic data from summer 2018 has been considered, which are used to know the current behavior of the system. On the other hand, with the webpage Demand Data Repository (DDR) of Eurocontrol a traffic forecast for summer 2024 has been generated, which is used to estimate the behaviour and capacity of the system in a future with more traffic. With the results analysis, it is possible to check that nowadays most aircraft would be authorized with a direct entry to the merge point, without waiting. For the 2024 case, most aircraft would have to stay inside the system with a waiting time due to the increase of flights. Lastly, in both scenarios route length increases, while it is possible to perform CDA thanks to the predictability obtained with the system.

L’objectiu principal d’aquest projecte és dissenyar un sistema de control automàtic per un nou procediment d’arribades a l’aeroport de Palma de Mallorca, el Point Merge System (PMS). Aquest nou sistema, proposat pel Cercle d’Economia de Mallorca, permet realitzar Continuous Descent Approach (CDA), reduint el consum de fuel, les emissions de CO2 i l’impacte acústic, mentre que es milloren els nivells de seguretat i s’augmenta la capacitat de trànsit d’arribada. A més a més, el fet d’introduir el control automàtic eliminaria la presència dels controladors, necessitant únicament una persona que supervisés el sistema. El concepte de PMS va ser desenvolupat per Eurocontrol i es basa en la fusió de dos fluxos d’arribada en un únic punt d’entrada, que després s’enllaça amb la pista de l’aeroport. Actualment aquests fluxos són gestionats pels controladors que donen la instrucció “direct-to” als pilots perquè es puguin dirigir cap al punt final, mentre que en aquest projecte ho farà el propi sistema. Per aconseguir l’objectiu del projecte s’ha utilitzat el programa Network Strategic Tool (NEST) d’Eurocontrol, que permet fer simulacions de trànsit aeri, juntament amb Matlab, amb el qual s’han llegit els arxius del NEST i s’han realitzat diferents càlculs de temps per determinar quan l’avió obté el “direct-to” i així garantir la seguretat. Els resultats obtinguts són per dos escenaris diferents. Per una banda, s’han considerat dades de trànsit real de l’estiu de 2018, amb les quals sabem el comportament del sistema a dia d’avui. Per altra banda, a través de la pàgina web Demand Data Repository (DDR) d’Eurocontrol s’ha generat una previsió de trànsit per l’estiu de 2024, amb la qual s’estima el comportament i la capacitat del sistema en un futur amb més trànsit. Amb l’anàlisi dels resultats, es comprova que actualment la majoria d’avions serien autoritzats amb una entrada directa al punt final, sense necessitat d’esperar. En el cas de l’any 2024, la majoria d’avions hauria d’estar dins del sistema amb un temps d’espera degut a l’augment dels vols. Per últim, en els dos escenaris la distància recorreguda augmenta, mentre que es pot fer una aproximació CDA gràcies a la predictibilitat obtinguda amb el sistem

Assessing the Environmental Impacts of Shared Autonomous Electric Vehicle Systems with Varying Adoption Levels Using Agent-Based Models

Scipedia content — Tue, 26 Jan 2021 17:55:41 +0100

div"In recent years, there has been considerable growth in the adoption and technology development of electric vehicles (EV), autonomous vehicles (AV), and ride sharing (RS). These technologies have the potential to improve transportation sustainability. Many studies have evaluated the environmental impacts of these technologies but the existing literature has three major gaps: (1) the adoption of these three technologies need to be evaluated considering their impact on each other, (2) many existing models do not evaluate systems on a common ground, and (3) the heterogeneous preferences of riders towards these emerging technologies are not fully incorporated. To address these gaps, this work studies and quantifies the environmental and efficiency gains that can be gained through these emerging transportation technologies by developing a Parameterized Preference-based Shared Autonomous Electric Vehicle (PP-SAEV) agent-based model. The model is then applied to a case study of New York City (NYC) taxis to evaluate the system performance with increasing AV, EV, and RS adoption."/div""div""br""/div""div"The outputs from the PP-SAEV model show that replacing taxi cabs in NYC with AVs along with RS potentially can reduce CO\\textsubscript{2} emissions by 866 metric Tones per day and increase average vehicle occupancy from 1.2 to 3 persons in vehicles with passenger seating capacity of 4. A prediction model based on the PP-SAEV output recommends that 6000 vehicles are needed to maintain the current level of service with 100\\% AV and RS adoption using capacity 4 taxis. Taxi fleets with capacity 4 with high RS and low AV adoption are also found to have the least CO\\textsubscript{2} emissions. Because the heterogeneous sharing preferences of riders have shown as the major limiting factor to ride sharing, these heterogeneous sharing preferences are further modelled. The results show that high service levels are achieved when all the riders are open to sharing, and the maximum service level is reached when 30\\% of riders will only accept shared rides and 70\\% of the riders are either indifferent to sharing or prefer to use ride sharing over riding alone. Additionally, the service level and waiting time of riders that are inflexible (will accept only shared or non-shared rides) are greatly impacted by varying mix of riders with different sharing preference. Finally, an optimization model was built to site charging stations in a system with continually increasing EV adoption. Using the best charging station locations, transforming a fleet of autonomous or traditional vehicles to electric vehicles does not significantly change the system service level. The results show that increasing the EV adoption in fleets with 100\\% RS and AV adoption reduced the daily CO\\textsubscript{2} emissions by about 861 Tones and transforming a fleet of traditional taxi cabs to electric taxi cabs reduced the daily CO\\textsubscript{2} emissions by 1100 Tones."/div""div""br""/div""div"In summary, this dissertation evaluates the potential growth of autonomous vehicles, ride sharing, and electric vehicles in systems where riders may have heterogeneous sharing preferences, from a system performance`s perspective and assesses the environmental impacts. The developed model and the insights gained from this study can inform policy makers to develop sustainable transportation systems incorporating the emerging transportation technologies."/div

Large rivers’ fish assemblages under multiple pressures

Scipedia content — Tue, 26 Jan 2021 17:54:25 +0100

Europäische große Flüsse wurden über Jahrhunderte entscheidend verändert und zu Wasserstraßen für die Schifffahrt ausgebaut. Flussregulierung, Begradigung und Hochwasserschutz tragen zu multiplen Stressoren bei, wobei die Schifffahrt bislang keine Beachtung als potentieller zusätzlicher Einflussfaktor (Stressor) fand. Die zentrale Fragestellung dieser Arbeit befasste sich mit der Rolle der Schifffahrt zwischen multiplen Stressoren und deren Auswirkungen auf die Fischgemeinschaften großer Flüsse. Hierzu wurde die „Large River Fish Database“ (LRDB), ein weltweit einzigartiger Datensatz zusammengestellt, der 2693 Befischungen an 358 Probestellen in 16 europäischen großen Flüssen enthält. Die Probestellen sind durch verschiedene Einflussfaktoren (Stressoren) und Schiffsverkehr beschrieben. Um ein für große Flüsse repräsentatives Abbild der Fischgemeinschaften zu erhalten, wurden zunächst die angewendeten Fischfangmethoden analysiert. Mit der Elektrofischerei wurden die höchsten Fischdichten und die höchste Biodiversität erfasst. Die Elektrofischerei ist daher für eine repräsentative Erfassung der Fischgemeinschaften großer Flüsse geeignet und wurde für weitere Analysen ausgewählt. Die kommerzielle Frachtschifffahrt trat als einer der einflussreichsten Stressoren hervor, zusammen mit erhöhter Fließgeschwindigkeit und dem Verlust von Überschwemmungsflächen. Dichten von insbesondere Habitat-sensitiven Fischen sanken bereits ab acht Frachtschiffen pro Tag signifikant ab. Darüberhinaus hatte auch die Freizeitschifffahrt (Flusskreuzfahrten und motorisierte Sportboote) deutliche und zu Frachtschiffen unterscheidbare ökologische Konsequenzen. Die Wirkungen der Schifffahrt sind ebenso verheerend wie die der hydromorphologischen Degradierung und benötigen eine gesonderte Beachtung im Flussmanagement und der Flussrevitalisierung. Freizeitboote und Flussdampfer wirken der Flussrenaturierung kleinerer Wasserstraßen entgegen und gefährden den ökologischen Erfolg des Blauen Bandes.

European large rivers have been tremendously modified over centuries and transformed into waterways for inland navigation. Extensive river modifications such as river regulation, channel straightening and flood protection have resulted in multiple pressures. However, inland navigation has not been considered as a potential pressure yet. This thesis aimed to assess the role of inland navigation among the most prevailing pressures in large rivers under field conditions. A worldwide unique and complementary dataset, the Large River Fish Database (LRDB) was compiled. The LRDB consists of 2693 fish samples assessed at 358 sampling sites in 16 European large rivers. Sites were characterized by various pressure variables and frequencies of ship traffic. To derive representative samples of large rivers fish assemblages, performance of various fishing gears applied was assessed. Electrofishing samples represented highest densities of fish and highest overall biodiversity. Therefore, electrofishing is suitable for fish-based assessments of large rivers and only electrofishing samples were selected to assess multiple pressures and inland navigation. Commercial cargo navigation appeared as the most influential pressures on large rivers fish assemblages among increased velocities and the loss of floodplains. Starting at already eight passing vessels per day, densities of particularly habitat-sensitive spawners significantly declined. Moreover, recreational navigation such as river cruises and motorized sport boats had distinct ecological consequences to those of cargo vessels. Inland navigation is as detrimental as the hydromorphological degradation of the river channel and requires specific attention in river management and rehabilitation. Pleasure boating (river cruises and sport boats) will counteract river rehabilitation also in smaller waterways and delimit ecological success of the Blue Band initiative in Germany.

Map-aided localization for autonomous driving using a particle filter

Scipedia content — Tue, 26 Jan 2021 17:46:01 +0100

Vehicles losing their GPS signal is a considerable issue for autonomous vehicles and can be a danger to people in their vicinity. To circumvent this issue, a particle filter localization technique using pre-generated offline Open Street Map (OSM) maps was investigated in a software simulation of Scania’s heavy-duty trucks. The localization technique runs in real-time and provides a way to localize the vehicle safely if the starting position is known. Access to global localization was limited, and the particle filter still succeeded in localizing the vehicle in the vicinity of the correct road segment by creating a graph of the map information and matching the trajectory to the vehicle’s sensor data. The mean error of the Particle filter localization technique in optimal conditions is 16m, which is 20% less than an optimally tuned dead reckoning solution. The mean error is about 50% larger compared to a Global Positioning System. The final product shows potential for expansion but requires more investigation to allow for real-world deployment. Att fordon kan mista sin GPS-signal är ett stort problem för autonoma fordon och kan vara en fara för människor i dess närhet. För att undvika detta problem föreslås en icke-global lokaliseringsteknik som använder Open Street Maps-kartor (OSM) och ett partikelfilter för att lokalisera fordonet i en mjukvarusimulation. Implementering körs i realtid och anger fordonets position med en tillräcklig träffsäkerhet för att det inte ska utgöra någon fara om dess startposition är känd. Globala lokaliseringsmöjligheter var begränsade, och partikelfiltret lyckades lokalisera fordonet till rätt vägsegment genom att konstruera en graf över den kartinformation den läst in och para ihop fordonets nuvarande färdväg med denna. Resultatet ger en lösning som optimalt har ett medelfel på 16m, vilket är 20% mindre än medelfelet jämfört med optimiserad dödräkning. Lösningen har ca 50% större medelfel än positionering med GPS. Slutresultatet visar en potential att användas i verkliga situationer, men kräver mer undersökningar.

Quantifying Traffic Congestion in Nairobi

Scipedia content — Tue, 26 Jan 2021 17:43:34 +0100

This thesis aims to give insight into a novel approach for quantifying car traffic in developing cities. This is necessary to improve efficiency in resource allocation for improvements in infrastructure. The project took form of a case study of neighborhoods in the city of Nairobi, Kenya. The approach consists of a method which relies on topics from the field of Topological Data Analysis, together with the use of large data sources from taxi services in the city. With this, both qualitative and quantitative insight can be given about the traffic. The method was proven useful for understanding how traffic spreads, and to differentiate between levels of congestion: quantifying it. However, it failed to detect the effect of previous improvements of infrastructure. Målet med rapporten är att ge insikt i en innovativ ansats för att kvantifiera biltrafik i utvecklingsstäder. Detta kommer som en nödvändighet för att kunna förbättra resursfördelning i utvecklandet av infrastruktur. Projektet utspelade sig som en fallstudie där stadsdelar i Nairobi, Kenya studerades. Ansatsen innefattar en metod som bygger på tekniker från topologisk dataanalys (eng. \\textit{Topological Data Analysis}), tillsammans med stora datakällor från taxitjänster i staden. Detta hoppas ge både kvalitativ och kvantitativ information om trafiken i staden. Metoden visade sig vara användbar för att förstå hur trafik sprider sig och att differentiera mellan nivåer av trafik, alltså att kvantifiera den. Tyvärr så misslyckades metoden visa sig användbar för att mäta förbättringar i infrastruktur.

Tesla and the electric vehicle market in 2018

Scipedia content — Tue, 26 Jan 2021 17:35:39 +0100

This Work Project presents a case study to be used in masters and executive education Strategy courses to better illustrate the dynamics of competition in markets with demand-side increasing returns. Through the real case of Tesla, this project intends to evaluate the strategic decisions pursued by the firm in the nascent electric vehicle market to overcome the hurdle of critical mass and provide a platform on which e-mobility can realize its full potential. In the analysis that follows, we conclude that Tesla created a model that exceeds the conventional auto business to allow its vehicles to move along the technology adoption curve.

Study of benefits Free Route areas in Europe

Scipedia content — Tue, 26 Jan 2021 17:35:03 +0100

The current airspace configuration is fragmented, defined by national airspaces according political borders that affects directly to the environment, aircraft and air navigation service costs. The future airspace of Europe is addressing new challenges to support the increase of the air traffic in a new airspace configuration. The free route airspace (FRA) is a new concept to restructure the sectors and airways that gives more flexibility to airspace users to create better and more efficient routes. In Free Route areas users may plan a route between a defined entry point and a defined exit point without reference to ATS network, always subject to air traffic control. This project aims to study the benefits of free route areas in two scenarios. One existing and a created one. The first scenario studies the advantages in the North European Free Route area which were implemented since 2015. The second scenario studies the impact of a free route airspace in a large scale. This project uses the NEST tool, from Eurocontrol, to simulate the traffic with and without FRA. Also, will be addressed future prognosis to support the long-term evaluation of the FRA concept. The structure of this project starts with a brief theory review of the Free Route Airspace concept and the first scenario evaluated. Then this project includes all the design steps and evaluation process in order to obtain the metrics evaluated. Finally, results of NEFRA and EUROFRA are presented. In general, the results of this project show that airspace users are greatly benefited from the implementation of Free Route Areas. Airlines can save money and fuel travelling shorter distance while safety is maintained. Also, environment is benefited in terms of greenhouse emissions. With the implementation of EUROFRA, approximately 5 thousand tons of CO2 can be saved per day.

La configuració actual del espai aeri està fragmentada, definida pels espais aeris nacionals segons les fronteres polítiques que afecten directament el medi ambient, els avions i els costos de la navegació aèria. L’espai aeri del futur a Europa ha de fer front als nous reptes per donar suport a l’augment del trànsit aeri en una nova configuració d’espai aeri. L’espai aeri Free Route (FRA) és un nou concepte per reestructurar els sectors i les aerovies que dóna més flexibilitat als usuaris de l’espai aeri per crear rutes millors i més eficients. A l’espai aeri Free Route, els usuaris poden planificar una ruta entre un punt d’entrada definit i un punt de sortida definit sense utilitzar la xarxa ATS, sempre subjecte al control de trànsit aeri. Aquest projecte té com a objectiu estudiar els beneficis de les àrees Free Route en dos escenaris. Un existent i un creat. El primer escenari estudia els avantatges de les àrees Free Rote del nord d'Europa que porten actius desde 2015. El segon escenari estudia l'impacte d'un espai aeri Free Route a gran escala. Aquest projecte utilitza l’eina NEST, d’Eurocontrol, per simular el trànsit amb i sense FRA. A més, es tractarà el pronòstic futur per donar suport a l’avaluació a llarg termini del concepte de FRA. L’estructura d’aquest projecte s’inicia amb una breu revisió teòrica del concepte d’espai aeri Free Route i del primer escenari avaluat. A continuació, aquest projecte inclou tots els passos de disseny i el procés d’avaluació per obtenir els paràmetres avaluats. Finalment, es presenten els resultats de NEFRA i EUROFRA. En general, els resultats d'aquest projecte mostren que els usuaris de l’espai aeri es beneficien enormement de la implementació d’àrees Free Route. Les companyies aèries poden estalviar diners i combustible viatjant menys distància mentre es manté la seguretat. A més, el medi ambient es beneficia en termes reducció d'emissions d’efecte hivernacle. Amb la implantació de l’EUROFRA, es poden estalviar aproximadament 5 mil tones de CO2 al dia.

Learning to Predict Pedestrians for Urban Automated Driving

Scipedia content — Tue, 26 Jan 2021 17:22:32 +0100

Navigating through densely populated urban areas is one of the most important challenges for self-driving vehicles. Accurate predictions are required to enable safe and efficient interactions with other road users. Pedestrians in particular pose major problems for current state of the art prediction systems. Apart from well-understood short-term predictions, used for Automatic Emergency Braking Systems, long-term predictions remain largely unresolved. In this thesis, we aim to advance pedestrian prediction systems to enable human- understandable automated driving. In view of a vehicle-centred road infrastructure with high vehicle speeds and scarce pedestrian crossings, early detection of pedestrian intentions and movements are the key to enabling such behaviour. These detections can enable automated vehicles to perform light brake manoeuvres at an early stage in order to let a pedestrian pass. This can eliminate the need to stop, which could significantly improve traffic flow and at the same time increase overall safety. Long-term full trajectory predictions are both costly and error-prone. Therefore we propose a hierarchical prediction system that splits the prediction into multiple simplified sub-problems using domain knowledge. Each sub-problem is designed to predict a meaningful part of pedestrian movement and to detect and remove pedestrians that are irrelevant for the current scenario as early as possible. Utilizing the given road geometry to identify crosswalks we first predict the pedestrians’ hidden intent to cross the road. For all crossing pedestrians we then propose a sparse motion prediction, providing a small set of key figures instead of a full trajectory. We claim that these domain-specific key figures, namely a time-to- cross and designated crossing point, are more than sufficient to describe future pedestrian motions for the planning system of an automated vehicle. To overcome problems from over-confident single value predictions we propose to utilize Quantile Regression techniques to predict reasonable uncertainties. Our evaluations show that we are able to robustly classify the pedestrians’ hidden intent using both standard and deep learning algorithms. Additionally we show that our hierarchical prediction system, including the sparse motion prediction, is suitable for a real-time system integration. With our large real-world dataset, featuring recordings from different crosswalks and days, we provide an evaluation regarding prediction accuracy, computational load and generalizability. During this analysis, we also found indications that it might be possible to transfer trained models to previously unseen pedestrian crossings if the road geometry has at least approximately the same pavement dimensions. Furthermore, we show how our sparse motion prediction can be integrated into a situation-based planning approach to allow safe and efficient real-time interactions with other traffic participants. For this we evaluate different interaction scenarios regarding safety, time efficiency and comfort impairment. We were able to show that in most of the scenarios it is possible to minimize movement jerks and eliminate the need to stop. The overall performance is only limited by very high traffic densities.

Research of driver's perception of novel traffic signals using an eye tracker

Scipedia content — Tue, 26 Jan 2021 17:21:51 +0100

Novo Mesto is a small town in the Slovenian countryside which is undergoing a new project of road safety. New traffic signals are to be placed in bus stops to give drivers awareness of children standing waiting for the bus. Our mission is to use an eye tracker (the Dikablis device by Ergoneers) to study the reaction of three test drivers against these new signals; if they do detect them or not and if they modify their driving behavior once noticed them. The methodology is to do a first test before the signal placements and another one after, and afterwards compare both situations. Results are satisfying, with high values of reliability, and make us think the new signals will be useful and will contribute to make the road a safer place for children. Outgoing

Une approche systématique de l'évaluation de la fiabilité des convertisseurs électroniques d'alimentation DC-DC

Scipedia content — Tue, 26 Jan 2021 17:20:53 +0100

Reliable and unceasing exploitation of power electronic converters plays a major part in every application. This PhD thesis comes up with new opened-up reliability assessment frameworks and demonstrates the feasibility of using multistate degraded system analysis and interval analysis as well for attaining much more accuracy in reliability evaluation. Considering self- and coupling degradation effects of the items and assessing reliability in the system level are important issues which are still lacking in the previous studies and the present thesis has made an effort to overcome these problems. The thesis tries to launch two distinct reliability assessment frameworks, namely interval reliability and Multistate degraded system reliability.Interval reliability is capable of introducing an interval useful lifetime for DC-DC power electronic converters in which the self and coupling degradations effects of items have been taken into account. Fundamentally, it is based on the conventional physics of failure reliability assessment. Based on this method, instead of obtaining an inaccurate reliability value, one can attain an interval for the reliability of a global system whose useful lifetime undoubtedly lays between the boundaries. This method is able to consider degradation dependencies and assess multi-component system level reliability but not redundant system. An attempt was made to enhance the conventional reliability framework to reach a systematic approach capable of estimating a reliability assessment considering self and mutual degradation effects and being able to evaluate system-level reliability including redundant system. Multistate degraded system reliability analysis is capable of estimating system-level reliability, while mission profile and physics of failure of the system’s items are taken into account. In addition, the self and mutual degradation effects of items on the operation of the global system have been considered. The multi-state degraded system reliability model exposed to multiple failure processes has been generalized. The operating condition of the global system is defined by a finite number of states. Not only can the proposed framework be employed in determining the reliability of the degraded systems in terms of multi-state functions, but also it can obtain the states of the systems by estimating the system state probabilities.As an application, a DC-DC power electronic system containing three critical items has been studied. In this case study, two power semiconductors, namely IGBT and diode, and a power capacitor have been considered as three degradation processes and their aging effects on the useful lifetime estimation of the power electronic system have been discussed. For having a sense about newly proposed reliability frameworks, a 3000W and 200/400 V conventional DC-DC converter for electric vehicle application exposed to WLTP driving cycle is considered.; La fiabilité et la sureté de fonctionnement de l'électronique de puissance jouent un rôle majeur aujourd'hui dans l'industrie. Cette thèse propose un nouveau cadre d'étude de la fiabilité à partir de deux méthodes afin d'améliorer la précision des études de fiabilité : une analyse utilisant la méthode des système dégradés multi état, et une analyse par intervalles. La considération des effets de dégradation propres et couplés de chaque composant est également une problématique qu'il reste aujourd'hui à étudier et qui est traitée dans ce travail.L'étude de la fiabilité par intervalles permet d'estimer des intervalles de durée de vie des convertisseurs DC/DC en prenant en compte les dégradations propres et mutuelles des composants. Fondamentalement, cette méthode est basée sur la compréhension des phénomènes physiques. A partir de cette méthode, on peut obtenir un intervalle pour la durée de vie d'un système complet. Cette méthode n'est toutefois pas adaptée aux systèmes redondants.De son côté, la fiabilité des systèmes dégradés multi-états est capable de proposer une étude au niveau système en prenant en compte le profil de mission et la physique des dégradations.Cette méthode a été généralisée dans cette thèse au procédés subissant de multiples dégradations. L'exemple d'un convertisseur DC/DC conprenant trois composants critiques a été étudié comme cas d'application. Deux composants semiconducteurs, diode et IGBT, et un condensateur sont considérés comme trois process de dégradation et l'effet de leur vieillissement sur la durée de vie du convertisseur est discutée. Le convertisseur étudié a pour puissance 3 kW (200/400V) et est dédié aux applications de type véhicule électrique. Il subit un profil de mission typique automobile (cycle WLTP).

Towards an Improved Safety Benefit Assessment for Heavy Trucks - Introduction of a framework for the combination of different data sources

Scipedia content — Tue, 26 Jan 2021 17:13:12 +0100

hough heavy goods vehicles (HGVs) were only involved in 4.4% out of more than 1 million crashes that occurred on European roads in 2017, their share in crashes with fatal outcome was almost three times larger (12%). Advanced Driver Assistance Systems (ADAS) have the potential to mitigate the consequences of these crashes or avoid them altogether. In order to prioritise the most promising system, several types of safety benefit assessment are performed separately and independently of each other. These assessments miss however a combination into a common output, i.e. they are not able to provide a holistic overview but only show compartmentalised results. The first objective of this thesis is to provide a framework that can incorporate multiple data sources and combine their results into one common safety benefit output. The proposed framework within this thesis is based on Bayesian modelling and can update prior information (e.g. simulation results of a new ADAS) with new observations (e.g. test track results of the ADAS). The framework can incorporate additional information such as user acceptance and market penetration of the ADAS for an improved benefit assessment. The output of the framework can easily be incorporated as prior knowledge in new safety benefit assessments, e.g. when new data is available. The second objective is to prepare the application of the framework for the assessment of the safety benefit associated to the introduction of new ADAS for long-haul trucks. In order to specify the most critical crash scenarios for HGVs in Europe, a detailed, three-level analysis of crashes involving long-haul trucks was performed, starting on a general European level and going to in-depth crash data. The identified target scenarios are (a) rear-end crashes with the truck as the striking vehicle, (b) crashes between a right-turning truck and adjacent cyclist and (c) crashes between a truck and a pedestrian crossing in front of the truck. These three scenarios should be the basis for ADAS development and further addressed by driver behaviour modelling in the future. Future work will focus on improving simulation results by incorporating more accurate driver models, that are better able to represent truck driver behaviour, e.g. brake or steering reactions. These models will help to obtain more valid simulation results, and thereby increase the output quality of the framework.

Second Life Batteries Faciliating Sustainable Transition in the Transport and Energy Sectors? : An Exploratory Field Study in Colombia

Scipedia content — Tue, 26 Jan 2021 17:12:03 +0100

The increasing number of vehicles in Colombian cities have resulted in alarmingly low quality of air, further resulting in increasing health issues. One potential solution to this issue could be a shift from ICEVs (internal combustion engine vehicles) to EVs (electric vehicles). However, EVs in Colombia are still very expensive, an issue that needs to be addressed in order for the EV market to increase enough to be able address the issue of low air quality in cities. One way of overcoming these cost barriers could be through implementation of a market for SLB (second life batteries), meaning that a battery retired from usage in EVs would be remanufactured, resold and reused in another application. Through SLB, the owner cost of EVs could potentially be decreased. SLB could also help improve the case for nondispatchable renewable energy sources by providing low cost BESS (battery energy storage solutions). Thus, SLB has the potential to facilitate sustainable transition within both the transport and the energy sector. This thesis aims to assess the potential of SLB in Colombia. This is done through a literature review where the current state of SLB is investigated, several interviews with potential stakeholders for a SLB market in Colombia, and a techno-economic assessment of four potential BESS applications in Colombia. The literature review provides with current knowledge and state of SLB in general. The interviews provide important insight to potential stakeholders’ view on SLB for the specific case of Colombia. The techno-economic assessment includes a sensitivity analysis aiming to provide insights in which factors, such as e.g. battery purchasing price or charging cost, that that gives rise to the largest impact on feasibility of SLB. Findings from the interviews shows a strong collective commitment from the interviewees to working towards cleaner air, resulting in high engagement and collaborative efforts between stakeholders for the SLB case. The main issue highlighted by stakeholders regards technoeconomic uncertainties of SLB. Findings from the techno-economic assessment indicates that SLB is viable for larger applications such as BESS at solar farms, but not for smaller applications such as backup power in residential buildings. However, SLB is not deemed to be a game changer for either application, and there are still many uncertainties regarding both technological and economic aspects that needs to be further investigated. The sensitivity analysis shows that the factors resulting in the highest impact on feasibility of SLB is battery SOH (state of health) at the beginning of SLB usage, and battery and repurposing cost. It will be hard to address both of these factors simultaneously due to a higher SOH would render higher battery prices, and vice versa. The findings from the thesis shows that SLB can facilitate sustainable transition within both the transport and energy sectors but is not to be considered a game changer for these sectors. However, even though SLB’s contribution to sustainable transition is not revolutionary, it is still necessary from a sustainability perspective. Given the environmental footprint of EV batteries and the amount of hazardous waste retired EV batteries will give rise to, circular economy must be pursued. Det ökande antalet fordon i colombianska städer har resulterat i oroväckande låg luftkvalitet, vilket ytterligare resulterat i ökande hälsoproblem. En potentiell lösning på det problemet kan vara en övergång från ICEVs (förbränningsmotorfordon) till EV (elfordon). EVs i Colombia är fortfarande väldigt dyra, en fråga som måste adresseras för att EV-marknaden ska kunna öka tillräckligt för att kunna ge en inverkan på problemet med låg luftkvalitet i städer. Ett sätt att övervinna dessa kostnadshinder skulle kunna vara genom att implementera en marknad för SLB (second life-batterier), vilket innebär att ett batteri som bedömts inte längre uppfylla kraven för användning i EVs, och därmed byts ut, skulle kunna byggas om, säljas vidare och återanvändas i andra applikationer. Genom SLB kan ägarkostnaderna för EVs potentiellt sänkas. SLB skulle också kunna användas för att tillhandahålla billigare BESS (batterilagringslösningar) hos icke-reglerbara förnyelsebara kraftverk, såsom solkraftverk. Således har SLB potentialen att underlätta för hållbara förändringar inom både transportsektorn och energisektorn. Den här uppsatsen ämnar att utvärdera SLBs potential i Colombia. Detta görs genom en litteraturöversikt där det nuvarande tillståndet av SLBs undersöks, flera intervjuer med potentiella intressenter för en SLB-marknad i Colombia, och en tekno-ekonomisk bedömning av fyra potentiella BESS-applikationer i Colombia. Litteraturöversikten samlar aktuell kunskap och status inom SLB i allmänhet. Intervjuerna ger viktig insikt om potentiella intressenters syn på SLB för det specifika fallet i Colombia. Den tekno-ekonomiska bedömningen inkluderar en känslighetsanalys som syftar till att ge insikter i vilka faktorer, som t.ex. batteriets inköpspris eller laddningskostnad, som ger upphov till den största effekten på SLBs genomförbarhet. Resultat från intervjuerna visar ett starkt kollektivt engagemang från de intervjuade att arbeta mot renare luft, vilket resulterar i högt engagemang och samarbete mellan intressenterna. Det största problemet med SLB från intressenternas synpunkt berör tekno-ekonomiska osäkerheter. Resultat från den tekno-ekonomiska bedömningen indikerar att SLB är ekonomiskt försvarbart för större applikationer som BESS vid solkraftverk, men inte för mindre applikationer som t.ex. för reservenergi i bostadshus. SLB anses dock inte vara ett genombrott för användning vid någon av applikationerna, och det finns fortfarande många osäkerheter när det gäller både tekniska och ekonomiska aspekter som måste undersökas ytterligare. Känslighetsanalysen visar att de faktorer som resulterar i den högsta påverkan på genomförbarheten av SLB är batteriets SOH (hälsotillstånd) i början av SLB-användning och kostnaden för batteri och ombyggnad av batterier. Det kommer dock att vara svårt att hantera båda dessa faktorer samtidigt på grund av att högre SOH skulle ge högre batteripriser, och vice versa. Resultaten från uppsatsen visar att SLB kan underlätta för hållbara förändringar inom både transport- och energisektorerna, men att det inte ska betraktas som något fantastiskt genombrott för dessa sektorer. Även fast SLBs bidrag till hållbara förändringar är inte revolutionerande, är det fortfarande en nödvändig faktor ur ett hållbarhetsperspektiv. Med tanke på miljöavtrycket för EV-batterier och mängden av farligt avfall som EV-batterier kommer att ge upphov till då de inte längre är önskvärda, måste cirkulär ekonomi bedrivas i största möjliga mån.

HITTING THE ACCELERATOR: WILL TESLA CRASH THE LOS ANGELES GRID?

Scipedia content — Tue, 26 Jan 2021 17:11:30 +0100

How many Teslas will it take to crash the Los Angeles, California, grid? This thesis conducts a thought experiment to explore whether rapid adoption of electric vehicles (EVs) in Los Angeles will reduce the reliability of electric power in the Los Angeles Department of Water and Power (LADWP) service territory. Federal and state regulations are encouraging the shift to electric transportation in support of policy priorities that include reducing greenhouse gas emissions and reducing dependence on foreign energy sources. However, high market penetration by EVs will change the patterns of electricity use, especially in urban areas. Under some scenarios, EVs could pose a risk to the reliability and resilience of the electric grid serving these areas. To explore this issue, I developed a model that projects the impact of EVs on the peak power load in Los Angeles in 2030 under different scenarios of EV market penetration and constraints on demand for vehicle charging (e.g., time-of-day pricing). I found that even with moderate EV penetration, if vehicle charging is unconstrained, the load placed on the LADWP grid will exceed the established reserve margin in 2030. Only by adopting some form of incentives for EV drivers to shift their power demands from the normal end-of-day charging routine will the LADWP be able to maintain the reliability and resilience of the power grid. http://archive.org/details/hittingtheaccele1094563490 Civilian, Department of Homeland Security Approved for public release; distribution is unlimited.

Understanding port performance: An examination of challenges in the contextualisation of performance in support of policy design in the port sector

Scipedia content — Tue, 26 Jan 2021 17:08:05 +0100

Owing to the prominence of maritime transport, the performance of ports as nodes in the maritime transport network is a critical enabler of a regions capability to trade internationally. Ensuring the performance of ports is therefore a frequent and prominent policy goal. Effective policy design requires an understanding of performance to evaluate and design policy interventions. A key challenge to evaluating port performance is the complexity of ports as infrastructure systems. Ports develop relative to the economic, physical and socio-political environments of the regions they serve. Understanding the performance of ports thus requires contextualisation of performance in respect of the port’s operating environment. In multi-port regions, this is particularly challenging, as the performance of an individual port is most likely to be impacted by the performance of related ports. The evaluation of performance must therefore be contextualised relative to the individual circumstances of a given port and those of related ports. This thesis aims to contribute to our understanding of how to evaluate port performance as it pertains to policy design. The thesis consists of a number of papers presented as chapters. Each chapter deals with a respective challenge to this process. The first paper presented in chapter 2, explores the dimensionality of performance and its implications for seaport performance evaluation. As entities, seaports produce a mix of private and public goods that have significant welfare implications for the regions they serve. In effect, performance in seaports can be viewed as multi-dimensional. The objective of this chapter is to conduct a systematic literature review of published studies on seaport performance measurement to identify, critically evaluate and integrate the various dimensions of seaport performance measurement. A review of the literature was thus carried out focusing on key questions in performance measurement system design, outlining what to measure and how to measure it. The study finds that the volume of studies has been expanding rapidly, leading to significant advancement in the development of methods to create different measures of port performance across an increasing number of dimensions. However, there has been less progress in advancing means to define what constitutes performance as a construct, particularly when performance is perceived as multidimensional. In this review, five dimensions of seaport performance were identified. In addition, a formative construct of performance was proposed, to be used in the design of performance measurement systems to address policy concerns when performance is of a multidimensional nature. Chapter 3 takes a temporal perspective, to examine the development of performance across ports in a port system over time in a case study approach. The paper examines performance change in the Irish state-owned port sector over the period 2000-2016. For analysis, qualitative sources are used to construct an explanatory account for quantitative measures of productivity, profitability and traffic shift-share change across the major ports within the system. The results show that overall change in performance largely follows that of the macro-economic performance of the region, characterised by pre-recession growth, decline during the recession and post-recession recovery. Across the ports, however, there was a notable divergence in performance post-recession. Identified factors affecting performance change across the period, include demand-side structural change, labour rationalisation, business model choice, and cargo mix choices. Chapter 4 investigates the effect of size on technical efficiency in peripheral port markets. In peripheral port markets, a limited volume of traffic creates challenges in sustaining multiple competing Port Authorities (PAs). With a limited size, smaller ports have difficulty in attracting the necessary traffic flows to leverage capital for development. In many European jurisdictions, recent policy reform has sought to concentrate resources in dominant ports or amalgamate smaller PAs to increase competitiveness and rationalize investments. This chapter formally examines the link between port size and achievable efficiencies through an efficiency analysis of Irish and Atlantic Spanish ports. To achieve this, the paper applies a two-step double bootstrap Data Envelopment Analysis (DEA) approach to examine the effect of relative size on technical efficiency across the two port systems in the period 2000-2015. The results indicate a positive relationship between size and technical efficiency amongst ports in peripheral regions. As the time-period covers the financial crisis, it is possible to further explore the effect of the recession and subsequent contraction in the market for port services on the relationship between size and technical efficiency. The findings indicate that the effect of size on technical efficiency becomes even stronger when market contraction is controlled for. Results also show that the efficiency gap between the larger and smaller ports increased considerably after the recession. Chapter 5 measures performance from a network demand perspective. In many regions, capacity for port services is provided by a network of gateway ports. These gateway ports act as entry and exit nodes for a region to the wider freight transport system. Understanding existing drivers of port choice and the substitutability between nodes within the network is important for informing policy decisions regarding the allocation of often scarce resources in developing capacity. The objective of this chapter is therefore to examine demand for and substitutability between nodes in the Irish port network. A random utility maximisation framework is employed to examine the probability of routing a vessel, conditional on having chosen to run a service, through a given node based on identifiable port attributes. Using the output of the modelling exercise, several policy scenarios are simulated to examine substitutability across the port network. The model of port demand is created using a full sample of port calls for the year 2016 using automatic identification system (AIS) data sourced from Marine Traffic. Finally, chapter 6 explores how port managers achieve performance in matching supply of port services with demand. For countries that rely on maritime trade, the timely and appropriate development of port capacity is of strategic national importance. To achieve this, an exploratory case study is carried out in the Irish state owned port sector, where the decision to develop capacity is examined with senior executives in Irish Port Authorities. To facilitate this enquiry, key concepts from the strategic management literature are evoked to reconceptualise the capacity planning process as a capabilities search problem. The purpose of this conceptualisation is to provide a strategic framework to comparatively analyse decision making regarding capacity planning across organisations. From the case study, five generic capabilities critical to supplying capacity for freight markets in the Irish context were identified. The findings of the case indicate that underlying strategic decisions to develop capacity are assumptions about future capabilities in each of the five categories, with categories highly interlinked. Additionally, it is clear that across port contexts, the strategic importance of various capabilities will remain contingent on contextual factors accruing to the ports operating environment. This leads to practical implications for how the long term capability to supply port services for freight markets is evaluated. It is argued that any assessment of future capacity development within a given port must be cognisant of all capabilities required to develop capacity. Furthermore, the relative strategic importance of given capabilities are highly contingent on the context in which capacity is being developed.

Open Aircraft Performance Modeling

Scipedia content — Tue, 26 Jan 2021 17:01:40 +0100

large number of stakeholders exist in the modern air traffic management ecosystem. Air transportation studies benefit from collaboration and the sharing of knowledge and findings between these different players. However, not all parties have equal access to information. Due to the lack of open-source tools and models, it is not always possible to undertake comparative studies and to repeat experiments. The barriers to accessing proprietary tools and models create major limitations in the field of air traffic management research. This dissertation investigates the methods necessary to construct an aircraft performance model based on open data, which can be used freely and redistributed without restrictions. The primary data source presented in this dissertation is aircraft surveillance data that can be intercepted openly with little to no restriction in most regions of the world. The eleven chapters in this dissertation follow the sequence of open data, open models, and performance estimations. This order corresponds to the three main parts of the dissertation. In the first part of the dissertation, open surveillance data is explored. Methods are developed to decode and process this data. Extraction of information is also made possible thanks to machine learning algorithms. The second part of the dissertation examines the main components of the open aircraft performance model. Models related to kinematics, thrust, drag polar, fuel flow, and weather are investigated. The third part of the dissertation looks into the possibility of using surveillance data to estimate aircraft performance parameters, for example, aircraft turn performance, aircraft mass, and thrust settings, for individual flights. With the goal of making future air traffic management studies more transparent, comparable, and reproducible, the models and tools proposed in this dissertation are fully open. The final aircraft performance model, OpenAP, proposed in this dissertation has proven to be an efficient open alternative to current closed-source models.

Comparing technologies and algorithms behind mapping and routing APIs for Electric Vehicles

Scipedia content — Tue, 26 Jan 2021 17:00:02 +0100

The fast-developing industry of electric vehicles is growing, and so is the driver community, which puts pressure on the electric charging grid. The purpose of this thesis is to simplify for the drivers of electric cars to charge their cars during trips. The research questions investigated are” How do the technologies and algorithms behind navigation APIs differ from each other?” and “What information is provided by the charging station APIs and how do they collect data about new stations?”. Information for the thesis was collected by reading and analyzing both documentation and previous work, as well as by conducting experiments. The study was limited to purely electric vehicles. We created an application to conduct experiments on the API combination Mapbox and Open Charge Map, we call it ChargeX. We compare, TomTom, Tesla, Plugshare, Google Maps and ChargeX. The most common shortest-path algorithms are Dijkstra’s, A* and Bidirectional A*. They provide reasonable solutions to the shortest path problem. The algorithms can be improved by considering traffic flow, travel time and distance between origin and destination and apply it as weights on the edges. What has the largest impact on the final route is the choice of charging stations. The algorithm for picking charging stations can be optimized in several ways for example by considering real time availability information of the charging stations, prioritize highways, calculate the temperature and altitude impact on the battery or prioritize faster chargers such as superchargers for Tesla.

Validating a bike network analysis score based on open data as a connectivity measure of urban cycling infrastructure adapted for European Cities

Scipedia content — Tue, 26 Jan 2021 16:59:08 +0100

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies Cycling has been considered a viable option to generate a modal shift from fossil dependent transportation modes. In this framework, measurements and tools that aid connected bicycle infrastructure planning have been developed. This is the case of the Bicycle Network Analysis score, a connectivity measure adapted for the U.S. It is based on the Levels of Traffic Stress methodology and computed mainly with OpenStreetMap data. Its aim is to quantify how well the low-stress bicycle network in a city connects people with the places they want to go. For this research, the BNA open source tool is adapted to a European context to validate its ability of quantifying low-stress connectivity. Three core elements are evaluated: stress network, destinations, and the overall score itself. They are related to cycling behaviors from two validation data sources: travel to work data in England and Wales, and crowdsourced bicycle trip routes in The Netherlands. The results indicate that in England and Wales, there is a significantly higher percentage of bicycle trips performed between origin-destination pairs with a low-stress connection between them. Additionally, a positive correlation is found between the percentage of bicycle trips within a city and its overall BNA score. In the Dutch case, the destinations core element is evaluated, determining that the destinations contemplated in the BNA score calculation are also among the highly frequented by cyclists. However, their importance within the score computation might require adjustments. Although a comprehensive validation cannot be achieved due to data limitations, evidence that providing low-stress connections between origins and destinations relates to bicycle commuting in cities is found. Therefore, special attention should be given to those measures that can greatly benefit the decision-making process when planning for sustainable cities.

Direct Demand Estimation for Bus Transit in Small Cities

Scipedia content — Tue, 26 Jan 2021 16:58:36 +0100

div" "p"Public transportation is vital for many people who do not have the means to use other forms of transportation. In small communities, transit service is often limited, due to funding constraints of the transit agency. In order to maximize the use of available funding resources, agencies strive to provide effective and efficient service that meets the needs of as many people as possible. To do this, effective service planning is critical."/p" "p" "/p" "p"Unlike traditional road-based transportation projects, transit service modifications can be implemented over the span of just a few weeks. In planning for these short-term changes, the traditional four-step transportation planning process is often inadequate. Yet, the characteristics of small communities and the resources available to them limit the applicability of existing transit demand models, which are generally intended for larger cities."/p" "p" "/p" "p"This research proposes a methodology for using population and demographic data from the Census Bureau, combined with stop-level ridership data from the transit agency, to develop models for forecasting transit ridership generated by a given geographic area with known population and socioeconomic characteristics. The product of this research is a methodology that can be applied to develop ridership models for transit agencies in small cities. To demonstrate the methodology, the thesis built ridership models using data from Lafayette, Indiana."/p" "p" "/p" "p"A total of four (4) ridership models are developed, giving a transit agency the choice to select a model, based on available data and desired predictive power. More complex models are expected to provide greater predictive power, but also require more time and data to implement. Simpler models may be adequate where data availability is a challenge. Finally, examples are provided to aid in applying the models to various situations. Aggregation levels of the American Community Survey (ACS) data provided some challenge in developing accurate models, however, the developed models are still expected to provide useful information, particularly in situations where local knowledge is limited, or where additional information is unavailable."/p" "/div" "br

Machine learning-based flight trajectories prediction and air traffic conflict resolution advisory

Scipedia content — Tue, 26 Jan 2021 16:56:55 +0100

The increasing in traffic demand has strained air traffic control system and controllers which lead to the need of novel and efficient conflict detection and resolution advisory. In the scope of this thesis, we concentrate on studying challenges in conflict detection and resolution by using machine learning approaches. We have attempted to learn and predict controller behaviors from data using Random Forest. We also propose a novel approach for probabilistic conflict detection by using Heteroscedastic Gaussian Process as predictive models and Bayesian Optimization for probabilistic conflict detection algorithm. Finally, we propose an artificial intelligent agent that is capable of resolving conflicts, in the presence of traffic and uncertainty. The conflict resolution task is formulated as a decision-making problem in large and complex action space, which is applicable for employing reinforcement learning algorithm. Our work includes the development of a learning environment, scenario state representation, reward function, and learning algorithm. Machine learning methods have showed their advantages and potential in conflict detection and resolution related challenges. However, more studies would be conducted to improve their performances such as airspace network representation, multi-agent reinforcement learning or controller's strategy reconstruction from data.; L'augmentation de la demande de trafic a mis à rude épreuve le système de contrôle de la circulation aérienne et les contrôleurs, d'où la nécessité d'un système novateur et efficace de détection et de résolution des conflits. Dans le cadre de cette thèse, nous nous concentrons sur l'étude des défis de la détection et de la résolution des conflits en utilisant des approches d'apprentissage machine. Nous avons essayé d'apprendre et de prédire les comportements des contrôleurs à partir de données utilisant Random Forest. Nous proposons également une nouvelle approche pour la détection probabiliste des conflits en utilisant le Processus Gaussien Hétéroscédastique comme modèles prédictifs et l'optimisation bayésienne pour l'algorithme de détection probabiliste des conflits. Enfin, nous proposons un agent intelligent artificiel capable de résoudre les conflits, en présence de trafic et d'incertitude. La tâche de résolution de conflit est formulée comme un problème de prise de décision dans un espace d'action vaste et complexe, qui est applicable pour l'utilisation d'un algorithme d'apprentissage par renforcement. Notre travail comprend le développement d'un environnement d'apprentissage, la représentation des états des scénarios, la fonction de récompense et l'algorithme d'apprentissage. Les méthodes d'apprentissage machine ont montré leurs avantages et leur potentiel dans la détection et la résolution des conflits. Cependant, d'autres études seraient menées pour améliorer leurs performances, telles que la représentation du réseau de l'espace aérien, l'apprentissage du renforcement multi-agent ou la reconstruction de la stratégie du contrôleur à partir de données.

Simplified Life Cycle Assessment Approaches and Potential Impact Shifts

Scipedia content — Tue, 26 Jan 2021 16:51:12 +0100

Road transport contributes to approximately one quarter of all EU greenhouse gas emissions and is the leading cause of air pollution in cities. There are significant measures aimed at the reduction of use phase environmental impacts; in the EU, these strategies focus on the decarbonisation of road transport, such as through the prioritization of low- and zero-emission vehicles. Electric vehicles are seen as one of the primary measures for reducing road transport impacts. However, the introduction of new technology includes new challenges throughout the vehicle life cycle, such as the need for critical raw materials, high-energy manufacturing, charging electricity, and waste management; this, in turn, leads to a risk of impact shifts between life cycle phases and impact categories. Life Cycle Assessment (LCA) is one way to analyse environmental impacts. Applying LCA and life cycle thinking in research and industry allows for the detection of impact shifts and environmental sub-optimisation. A full LCA study is demanding in terms of both data collection efforts and user expertise requirements. The need to simplify the process and results of an assessment in order to support decision-making was identified in the early days of LCA development. There are numerous simplification approaches in LCA. Previously, the most prominent simplification terms were screening and streamlined LCA; now, a multitude of names and approaches have emerged. There is no consensus in the LCA community about LCA simplifications. In some cases, the line between what should be considered an LCA, simplified LCA or neither is fuzzy. The haphazard application of simplifications in LCA studies undermines the transparency and confidence in results. The aim of this thesis is to use the life cycle perspective guided by simplified LCA approaches to increase our understanding of the risk of impact shifts, resulting from measures to reduce vehicle environmental impacts. Four appended publications present five LCA studies of road vehicles. All appended studies are simplified using different approaches. The studies examine different impact reduction measures such as changing drivetrains, reducing particulate emissions from braking, and the scrapping of old vehicles. A fifth publication is a literature review that explores the common understanding of simplifications used in published LCA studies. The review identifies and investigates the types of simplifications used and discusses how these might be categorised. The appended LCA studies examine both impact shifts from one life cycle phase to another and between impact categories. It is difficult to determine whether a decrease in a life cycle phase or impact category could offset an increase in another and, therefore, to be able to determine if an impact shift is an acceptable compromise. New smart materials are expected to solve many environmental impact issues; however, there are risks associated with insufficient life cycle inventory data, limitations in knowledge about potential environmental impacts, and inefficient regulations covering new materials. The analysis of simplification approaches and case studies indicates that most simplifications are motivated by the lack of primary data. Additionally, study findings strengthen concerns about the significant inconsistency in LCA simplification terminology and how well approaches are described in individual studies. There is a need for a common simplification terminology and reporting standard. Due to the wide variety of purposes, scenarios, and products assessed, it is impossible to devise a one-size-fits-all approach for simplifications, especially if the aim is to identify potential impact shifts. Vägtransporter orsakar ungefär en fjärdedel av EUs totala utsläpp av växthusgaser och är den ledande orsaken till luftföroreningar i städer. Betydande åtgärder syftar till att minska användningsfasens miljöpåverkan. EUs strategier fokuserar på att minska vägtransporters koldioxidutsläpp, t.ex. genom att prioritera fordon med låga eller inga användning-utsläpp. Elektriska fordon ses som en av de främsta åtgärderna för att minska miljöpåverkan från vägtransport. Dock innebär introduktionen av ny teknik nya utmaningar längs fordonets livscykel, t.ex. behov av kritiska råmaterial, högenergiproduktion, ökad el-behov vid laddning och avfallshantering. Det finns en risk för förskjutning av miljöpåverkan mellan livscykelfaser och påverkanskategorier. Livscykelanalys (LCA) är ett sätt att analysera miljöpåverkan. Möjligheten att upptäcka förskjutning av miljöpåverkan och ineffektiva åtgärder för miljön är en anledning till att tillämpa LCA och livscykeltänkande inom forskning och industri. En fullständig LCA-studie kräver både betydande datainsamlingsinsatser och krav på användarexpertis. Behovet av att förenkla processen och utvärderingsresultaten för att stödja beslut identifierades redan tidigt under utvecklingen av LCA. Det finns en betydande mängd av LCA förenklingar. De mest framträdande förenklingstillvägagångssätten var tidigare ”screening” och ”streamlined” LCA, dessutom har en mängd andra namn och tillvägagångssätt dykt upp. Det finns ingen konsensus inom LCA-världen om hanteringen av LCA förenklingar. I vissa fall är gränsen luddig mellan vad som ska betraktas som en LCA, förenklad LCA och ingendera. Godtycklig tillämpning av förenklingar i LCA-studier undergräver transparensen och förtroendet för resultaten. Syftet med denna avhandling är att öka förståelsen för risken för förskjutning av miljöpåverkan, vid åtgärder för att minska fordonens påverkan, genom att använda livscykelperspektivet stödd av förenklad LCA. De fyra publikationerna inkluderar fem LCA-studier av vägfordon och fordonskomponenter. Alla fem studierna är förenklade genom olika tillvägagångssätt. Studierna undersöker olika miljöåtgärder så som att byta drivlina, minska partikelutsläpp vid bromsning och skrotning av gamla fordon. En femte publikation undersöker också den gemensamma förståelsen för LCA förenklingar, genom en litteraturöversikt av publicerade LCA-studier. Litteraturöversikten identifierade och undersökte vilka förenklingar som används och hur dessa skulle kunna kategoriseras. De inkluderade LCA-studierna exemplifierade både förskjutning av miljöpåverkan mellan livscykelfaser och påverkanskategorier. Det är svårt att avgöra om en minskning i en livscykelfas eller påverkanskategori kan kompensera för en ökning i en annan. Detta betyder att det är komplicerat att kunna avgöra om en förskjutning av miljöpåverkan är en acceptabel kompromiss. Nya smarta material förväntas vara lösningen för många miljöproblem. Det finns emellertid risker med otillräcklig LCI-data, kunskapsbegränsningar angående potentiella miljökonsekvenser och ineffektiva regler gällande nya material. Analysen av förenklingstillvägagångssätt och fallstudier indikerade att de flesta förenklingar styrdes av brist på primärdata. Dessutom stärktes anledningen till oro gällande den betydande inkonsekvens i LCA-förenklingsterminologin och hur väl tillvägagångssätten beskrivs i enskilda studier. Det finns ett behov av en gemensam terminologi och rapporteringsstandard för LCA förenklingstillvägagångssätt. På grund av studiers varierande syften, scenarier och analyserade produkter är det omöjligt att utforma ett generellt tillvägagångssätt för alla LCA förenklingar, särskilt om syftet är att identifiera potentiella förskjutningar av miljöpåverkan.

Queueing models for urban traffic networks

Scipedia content — Tue, 26 Jan 2021 16:45:24 +0100

With a growing population, traffic congestion puts a strain on individual travellers, economy and the environment and forms a major problem for cities all over the world. To decrease congestion, it is crucial to utilise the existing infrastructure more efficiently by using optimal traffic-light control. This requires a thorough analysis of possible control policies and their influence on the performance of the traffic network. For the analysis, we develop discrete-time queueing models and use them to compare different traffic-light control settings. Moreover, we present a novel computational approach for such queueing models. In our models, we take into account acceleration of the vehicles and the correlation between arrivals, which leads to accurate predictions of the delays. We focus on several topics concerning traffic control. First, we analyse and compare two types of control: fixed and semi-actuated control. We show the fundamental differences between these types in terms of the system performance and optimisation of control parameters. Second, we propose a measure of green-wave efficiency and study how the green waves affect the vehicles delay. We observe that a high green-wave efficiency does not necessarily mean short delays. Finally, we construct a transient model for large traffic networks with traffic-light and priority intersections. This model is designed to be used for model-based online traffic control. Traffic models developed in this thesis as well as many other queueing systems can be analysed using the probability-generating-function (pgf) technique, which often leads to expressions in terms of the (complex) roots of a certain equation. For a class of pgfs with a rational form, we show that it is not necessary to compute the roots in order to evaluate these expressions. Instead, one can use contour integrals, which is computationally a more reliable approach than the root-finding method.

A traffic-based method for safety impact assessment of road vehicle automation

Scipedia content — Tue, 26 Jan 2021 16:41:40 +0100

Identifying and evaluating the safety performance of road vehicle automation is one of the major challenges still to solve before market introduction of these functions. The assessment of these functions is highly challenging due to the increasing complexity of algorithms for environment perception and decision-making. In addition, the achievable level of safety is still an open question. To evaluate the achievable level of safety, this thesis introduces a new data-driven framework for safety impact assessment of road vehicle automation. The presented framework features human driver performance as a reference for assessment. The developed framework comprises a three-step approach: First, the effectiveness fields, the accidents and situations potentially addressed by the automated driving functions, are identified and clustered in the input data into driving scenarios. The considered driving scenarios are derived from the accident type catalogue built on decades of experience in accident research and thus covering all physically possible accident constellations. It is assumed that these accident constellations do not change with road vehicle automation, while their frequency of occurrence and their severity may change. Second, the change of frequency of occurrence of driving scenarios can be determined for mixed traffic conditions using traffic simulations with novel driver behaviour models representing human errors in the traffic simulations. In a third step, the change in severity within driving scenarios is assessed using human driver performance models as a reference. Simulator studies showed that human driver performance is based on feedforward control in incident situations while reaction time and reaction intensity are gamma-distributed in the selected driver population. The distinction of the human driving behaviour in these two models is particularly sensible as driver behaviour models influence the number, hence the frequency of incident driving scenarios, while driver performance models reflect the behaviour within an incident, thus the severity of a driving scenario. In consequence, this partitioning reflects the structure of the overall assessment approach. Finally, the resulting assessment of changed frequency and severity within the classified scenarios can be scaled-up by using accident statistics. The novel framework is exemplarily applied to investigate the level of safety of two different automated driving functions operating in motorway- and urban domain. This proves that the developed approach is applicable to automated driving functions of all automation levels (SAE 1- 5) and operation domains.

Mixing quantitative and qualitative methods for sustainable transportation in smart cities

Scipedia content — Tue, 26 Jan 2021 16:40:54 +0100

Evaluation of different machine learning models for the prediction of electric or hybrid vehicle buyers and identification of the characteristics of the buyers in the EU

Scipedia content — Tue, 26 Jan 2021 16:36:50 +0100

The main goal of this thesis is to evaluate different machine learning models in order to classify buyers of an electric or a hybrid vehicle and to identify the characteristics of the buyers in the European Union. Machine learning algorithms and techniques were adopted to analyze the dataset and to create models that could predict, with a certain accuracy, the customer’s willingness to buy an EV. Identification of the characteristics of the buyers were based on the identified most important features from the machine learning models and statistical analysis. The research consisted of exploratory and explanatory methods (mixed method) with quantitative and qualitative techniques. Quantitative technique was applied to convert categorical values to ordinal and nominal numeric values, to establish cause and effect relationship between the variables by using statistical analysis and to apply machine learning methods on the dataset. The quantitative results were then analyzed by using quantitative and qualitative techniques in order to identify the characteristics of the buyers. The data analytics part relied on a publicly available large dataset from the EU containing transport and mobility related data. From the experiments with logistics regression, support vector machine, random forest, gradient boosting classifier and the artificial neural network it was found that ANN is the best model to identify who won’t buy an EV and gradient boosting classifier is the best model to identify who would like to buy and EV. ML based feature importance identification methods (MDI, permutation feature importance) were used to analyze the characteristics of the buyers. The major buyer’s characteristics found in this thesis are environmental concern, knowledge on car sharing, country of residence, education, control traffic, gender, incentive, education and location of residence. Authors have recommended green marketing as the potential enablers towards a faster and larger adoption of electrical vehicles in the market as environmental impact was found as the most significant behavior of the buyer. Finally, for the future researchers, the authors have recommended fine-tuning the algorithms extensively in order to achieve better accuracy and to collect primary data based on the most important features identified in this thesis.

A model for air transport market competition assessment : airline and alliance perspective

Scipedia content — Tue, 26 Jan 2021 16:35:53 +0100

The thesis deals with several aspects of competition in long-haul market that is characterized by the presence of full-service network carriers that are typically members of large alliance groups and low-cost carrier that operates independently from any cooperation agreement. The thesis focuses on transatlantic market as one of the most lucrative airline market in the world characterized by the great number of full-service network carriers and recent influx of few low-cost carriers. In order to properly investigate the impact of low-cost carrier on full-service network carriers on competitive routes, three models were developed in the thesis. The first model presents the original econometric model designed to examine the impact of low-cost carrier on full-service network carrier’s price and number of passengers in the predefined set of long-haul city-pair markets. As airlines aim to obtain as larger portion of the market as possible, the second model in the thesis was developed to predict the airline market share on the routes characterized by the presence of low-cost carrier, as one of the competitor in long-haul city-pair markets. The model is based on the application of fuzzy logic. Taking into account the key factors that determine airline market share (price and frequency of service), the proposed market share model can provide satisfactory results without taking into consideration passengers’ perceptions towards different aspects of airline service. Measuring the airline efficiency becomes an inevitable step in assessing the airline competitive advantage. The fuzzy-based DEA CCR model is developed including the set of input and output variables carefully derived to reflect the current market outlook. The results show that major airlines which operate within alliances are generally more competitive than other mid-sized carriers, primarily due to the benefits derived from the economy of density. Doktorska disertacija razmatra nekoliko aspekata konkurencije na tržištu dugolinijskog saobraćaja na kome su prisutne kako tradicionalne aviokompanije, koje su uglavnom i članice neke od vodećih alijansi, tako i niskotarifne aviokompanije, koje posluju nezavisno od bilo kakvog korporativnog udruživanja. Fokus disertacije je na severnoatlantskom tržištu koje se ubraja u najatraktivnija tržišta na svetu na kome je tradicionalno prisutan veliki broj tradicionalnih aviokompanija, ali od skoro, i neznatan broj niskotarifnih aviokompanija. U doktorskoj disertaciji su razvijena tri modela sa ciljem da se detaljno utvrdi uticaj koji niskotarifni prevozilac ima na svoje konkurente, tradicionalne prevozioce, na dugolinijskim rutama. Prvi model predstavlja originalno razvijeni ekonometrijski model koji za cilj ima utvrđivanje uticaja niskotarifnog prevozioca na cene karata i broj prevezenih putnika tradicionalnog prevozioca na unapred definisanom skupu dugolinijskih ruta koje povezuju određene parove gradova. S obzirom na to da je jedan od osnovih ciljeva svake aviokompanije da ostvari što veći udeo na tržištu, u doktorskoj disertaciji je razvijen robusni model za predikciju učešća na tržištu aviokompanija koje obavljaju saobraćaj na dugolinijskim linijama na kojima postoji konkurencija od strane niskotarifnog prevozioca. Model je baziran na primeni fazi logike. Uzimajući u obzir ključne faktore koji određuju udeo na tržištu posmatrane aviokompanije, predloženi model daje zadovoljavajuće rezultate bez potrebe uzimanja u obzir preferencije putnika prema određenim aspektima usluge. Merenje efikasnosti aviokompanija predstavlja neizostavni stepenik u oceni konkurentske prednosti posmatrane aviokompanije. Fazi DEA CCR model razvijen u ovoj disertaciji je baziran na pažljivo izabranom skupu ulaznih i izlaznih promenljivih kako bi što bolje opisalo trenutno stanje na evropskom tržištu. Rezultati ukazuju da su velike tradicionalne aviokompanije, koje ujedno predstvaljaju i stožere alijansi, konkurentnije od manjihtradicionalnih aviokomapanija, pre svega zbog benefita ostvarenih kroz efekat ekonomije obima.

Proposal for the design of modular container terminals dedicated to short sea shipping in Brazil.

Scipedia content — Tue, 26 Jan 2021 16:31:02 +0100

O Plano Nacional de Logística e Transportes (PNLT) sinalizou a intenção de uma mudança substancial na matriz de transporte de cargas brasileira, com a diminuição do modal rodoviário e uma transição do modal aquaviário de 13 para 29% até 2025, o que só será possível com a ampliação da cabotagem. Desta forma, o presente trabalho dimensiona terminais \\"rápidos\\" de contêineres dedicados à cabotagem, que a partir de sua implantação possam ser ampliados gradativamente. Por meio de simulação de eventos discretos, o melhor layout modular, dimensionado por berço, foi definido de acordo com a demanda de contêineres movimentados e equipamentos utilizados, de forma a identificar gargalos e obter a melhor opção de modularização. Tal abordagem de terminais \\"rápidos\\" dedicados permitiria a desburocratização do sistema atual e a redução dos custos e tempos de armazenamento, tornando a cabotagem mais competitiva. The National Logistics and Transport Plan (PNLT) has the intention of a substantial change in the Brazilian cargo transportation matrix, with the reduction of the road modal and a transition from 13 to 29% in the waterway modal by 2025, which will only be possible with the increase of short sea shipping. Thus, the present work will size a modular \\"fast\\" containers terminal dedicated to short sea shipping, that when implemented could be gradually extended. Using discrete events simulation, the best modular layout, dimensioned by berths, was defined according to containers demand and chosen equipments, in order to identify bottlenecks and the best modularization option. Such an approach of dedicated \\"fast\\" terminals would allow the reduction of bureaucratization of the current system and transport and storage costs and times, making short sea shipping more competitive.

Evaluation of Adaptive Traffic Signal Control Using Traffic Simulation : A case study in Addis Ababa, Ethiopia

Scipedia content — Tue, 26 Jan 2021 16:29:33 +0100

One of the most significant urban transport problems is traffic congestion. All major cities both in developed and developing countries are facing the problem due to increasing travel demand caused by increasing urbanization and the attendant economic and population growth. Recognizing the growing burden of traffic congestion, community leaders and transportation planners in Addis Ababa are still actively promoting large-scale road constructions to alleviate traffic congestion. Although Intelligent Transportation Systems(ITS) applications seem to have the potential to improve signalization performance, highly congested intersections in Addis Ababa are still controlled by a timed signal and manual operation. Moreover, these pre-timed signal controls are functioning sub-optimally as they are not being regularly monitored and updated to cope with varying traffic demands. Even though the benefits are well known theoretically, at the time of writing of this thesis, Adaptive Traffic Signal Controllers (ATSC) haven’t been deployed in Ethiopia and no research has been conducted to demonstrate and quantify their effectiveness. This master’s research thesis, therefore, intends to fill the identified gap, by undertaking a microscopic traffic simulation investigation, to evaluate the benefits of adopting a Traffic-responsive Urban Control (TUC) strategy and optimizing traffic signal timings. For the purpose of this study, an oversaturated three-intersection test corridor located in the heart of Addis Ababa city is modeled in VISSIM using real-world traffic data. After validating the calibrated model, the corridor was evaluated with the existing pre-timed, TRANSYT optimized pre-timed plan and TUC strategy. Multiple simulation runs were then made for each scenario alternatives and various measures of effectiveness were considered in the evaluation process. Simulation evaluation has demonstrated an average delay reduction of 24.17% when the existing pre-timed alternative is compared to TRANSYT optimized plan and 35% when compared to the TUC strategy. Overall evaluation results indicate that deploying the TUC strategy and optimizing the aging pre-timed signal plans exhibits a significant flow improvement. It is expected that the result of the thesis work will be an input for future comprehensive policy development processes.

Analyzing and Modeling Capacity for Decentralized Air Traffic Control

Scipedia content — Tue, 26 Jan 2021 16:27:49 +0100

The current system of Air Traffic Control (ATC) relies on a centralized control architecture. At its core, this system is heavily dependent on manual intervention by human Air Traffic Controllers (ATCos) to ensure safe operations. The capacity of this system is, therefore, closely tied to the maximum workload that can be tolerated by ATCos. Although this system has served the needs of the air transportation industry thus far, the increasing delays and congestion reported in many areas indicates that the current centralized operational model is rapidly approaching saturation levels. To cope with the expected future increases of traffic demand, many researchers have proposed a transition to a decentralized traffic separation paradigm in en route airspaces. Although there are several variants of decentralized ATC, this thesis focuses on a variant known as self-separation. In self-separated airspace, each individual aircraft is responsible for its own separation with all surrounding traffic. To facilitate self-separation, significant research effort has been devoted towards the development of new algorithms for automated airborne Conflict Detection and Resolution (CD&R). However, in spite of over two decades of active research highlighting its theorized benefits, decentralization/self-separation is yet to be deployed in the field. From a technical point of view a lack of understanding on three open issues namely airspace design, airspace safety modeling, and airspace capacity modeling, have impeded its further development and implementation. The goal of this research is to address these three open problems in order to bring self-separated ATC closer to reality. Consequently, the main body of this thesis is divided into three parts, with each part tackling one of the three aforementioned open problems...

Business models adopted by car sharing companies in the context of smart mobility: multiple case studies in companies operating in Brazil

Scipedia content — Tue, 26 Jan 2021 16:18:19 +0100

cidades inteligentes emergiram como uma alternativa no trato das dificuldades oriundas do crescimento populacional observado nas áreas urbanizadas. Entre as iniciativas propostas por essa nova abordagem nos espaços urbanos, destaca-se a mobilidade inteligente. Ela propõe o uso dos recursos tecnológicos a fim de aprimorar a experiência de deslocamento de pessoas e de cargas, objetivando melhorar a qualidade de vida dos cidadãos. Nesse contexto, ressalta-se a importância do compartilhamento de carros como uma das alternativas para reduzir os índices de congestionamento, a emissão de poluentes e a demanda por áreas de estacionamento; além disso, esse serviço promove a interação com outros modais de transporte e os hábitos mais saudáveis entre os indivíduos que os utilizam. Ao analisar os modelos de negócio das empresas que operam nesse mercado, notam-se diferentes modalidades: compartilhamento de carros (ida e volta), compartilhamento de carros (trecho único), compartilhamento de carros (P2P), compartilhamento de corridas e caronas, empresas de redes de transporte e serviços de táxi. Também é possível identificar estreita relação com o consumo colaborativo (também denominado economia compartilhada), fenômeno amplamente explorado a partir da década de 2000, que fomenta o uso ou acesso aos bens em detrimento da propriedade. Assim, os usuários de carros compartilhados podem utilizá-los sem a incidência das obrigações e dos custos fixos associados à posse desses bens. Ambos os paradigmas utilizam a Internet, as redes sociais, os sistemas de informação e os recursos tecnológicos para prover seus serviços e conectar os usuários, criando as chamadas plataformas multilaterais. Estas suportam a criação e a operação em espaços físicos ou virtuais, conectando diferentes grupos de usuários; assim, ao reduzir os custos e as dificuldades desses encontros, disponibiliza-se um ambiente favorável à realização das transações, ou seja, ao compartilhamento dos carros. Esta tese de doutorado aplicou a análise qualitativa comparativa (QCA), a técnica MSDO, a análise de conteúdo e a análise cruzada de casos aos modelos de negócio de 14 organizações que atuam no segmento de carros compartilhados com a finalidade de identificar e descrever como os componentes da mobilidade inteligente, do consumo colaborativo e das plataformas multilaterais foram incorporados nas operações dessas companhias por meio de estudos de caso múltiplos. Os resultados alcançados indicaram alguns fatores críticos do sucesso empresarial desses modelos de negócio, entre eles: a análise de dados massivos por intermédio de ferramentas de big data, a disponibilização de aplicativos para dispositivos móveis, a implementação dos recursos de segurança física e lógica para os usuários dos serviços de carros compartilhados, o estímulo à colaboração on-line e ao uso de redes sociais e a operação em um mercado regulamentado. Devido à causalidade assimétrica, também emergiram componentes associados ao insucesso, entre eles: a ausência do uso de ferramentas de big data para análise dos dados massivos dos usuários; a indisponibilidade de aplicativos para dispositivos móveis; os recursos ineficazes de segurança física e lógica; a adoção de estratégias inócuas ou ausentes para a resolução do problema de massa crítica nas plataformas multilaterais; a dificuldade na obtenção de recursos financeiros para realizar investimentos nos diferentes grupos de usuários e a operação em um mercado sem regulamentação. Smart cities emerged as an alternative in dealing with the difficulties arising from population growth observed in urbanized areas. Among the initiatives proposed by this new approach in urban spaces, smart mobility stands out as an essential service for the operation of cities. It proposes the use of technological resources in order to improve the experience of moving people and cargo, aiming to improve the quality of life of citizens. In this context, the importance of car sharing is highlighted as one of the alternatives to reduce congestion rates, the emission of pollutants and the demand for parking areas; in addition, this service promotes interaction with other transport modes and healthier habits among the individuals who use it. When analyzing the business models of the companies that operate in this market, different modalities are observed: car sharing (round trip), car sharing (one way), car sharing (P2P), carpooling, transport network companies and taxi services. It is also possible to identify a close relationship with collaborative consumption (also called sharing economy), a phenomenon widely exploited since the last decade, which fosters the use or access to goods over property. Thus, users of shared cars can use them without the incidence of the obligations and the fixed costs associated with the possession of these goods. Both paradigms use the Internet, social networks, information systems and technological resources to provide their services and connect users, creating the so-called multisided platforms. These support operation in physical or virtual spaces, connecting different groups of users; thus, by reducing the costs and difficulties of these matches, a favorable environment is provided to carry out the transactions, that is, the car sharing. This PhD thesis applied the qualitative comparative analysis (QCA), the MSDO technique, content analysis and cross-case analysis to the business models of 14 organizations operating in the car sharing segment with the purpose of identifying and describing how the components of smart mobility, collaborative consumption and multisided platforms have been incorporated into the operations of these companies through multiple case studies. The results achieved indicated some critical success factors of these business models, among them: analyzing massive data through big data tools, making mobile applications available, implementing physical and logical security features for users of car sharing services, the stimulation of online collaboration and the use of social networks and the operation in a regulated market. Due to asymmetric causality, components associated with failure also emerged, among them: the absence of the use of big data tools to analyze the users\\' massive data; the unavailability of mobile applications; inefficient physical and logical security features; the adoption of innocuous or absent strategies for solving the critical mass problem in multisided platforms; the difficulty in obtaining the financial resources to make investments in different groups of users and the operation in a market without regulation.

Analysis of Inductive Power Transfer Systems for Electric Vehicle Charging Applications

Scipedia content — Tue, 26 Jan 2021 16:14:57 +0100

This research report is structured in 7 Chapters which pretend to guide the reader from a general point of view of Wireless Power Transfer (WPT) and its applications, to a deep and better understanding of Inductive Power Transfer (IPT) applied to Wireless Electric Vehicle Charging Systems (WEVCS). To do so, after the background introduction, each chapter studies a different part of the IPT system, ending up with the analysis of the simulation and hardware results.The background introduction is shown in Chapter 3, and explainshow energy started to be transferred wirelessly along history, classifying WPT into near-field (NF) and far-field (FF). Focus has been placed in NF WPT explaining inductive, capacitive and resonant variants, as the main existing forms of transferring energy through electromagnetic waves. Additionally, applications of NF have been commented concerning the charge of portable devices, electric transportation or biomedical implants. Wireless chargersfor electric vehicles are within the scope of this report. Hence,a detailed explanation of the two main topologies, static wireless charging (SWC) and dynamic wireless charging (DWC) has been given. To finish the review, information regarding a safe application following the current regulations has been mentioned as long as the principal standards that aimto smooththe path towards an early adaptation of IPT technology for EV charging purposes.In Chapter 4,IPT has been demonstratedwith mathematical expressions so as to be able to model thesystem that hereinafter will be simulated and validated. It starts with the formulation to get the relationship between the flux linkage and the currents, followed by an equivalent circuit representation. An initial analysis of the results can bealready obtained at this point.Howeverto increase the coupler’s efficiency a compensation network is added to either the equivalent circuit and the previous equations. The last part of the chapter is the design process of the coupler following an iterated procedure, where based on the charging specifications, by fixing some desired parameters the transmitter and receiver coils can be developed. Chapter 5explains the power electronics converters, essential in this system to increase the frequency up to de kHz range and reduce the size of its passive components. The converters used in the simulation and the hardware implementation are a DC/AC H-bridge inverter with Silicon Carbide (SiC) MOSFETs due to the high switching frequency intended to be used, and a diode bridge rectifier to turn the AC into DC and be able to charge thevehicle’s battery. Both converters have been simulated, first separately and then together to see the overall performance. Finally, a low pass filter has been added to smooth the ripple of the voltage and current of the load.The final components ordered have been listed and explained in Chapter 6, using the real values of the parameters given by the supplier to calculate and simulate the results. The results have been put together in Chapter 7, on theone hand the simulation results obtained with Matlab/Simulink and on the other hand the tests carried through with the hardware in the laboratory. The 4Reportgoal of this last chapter is to validate the theoretical results. An intermediate stage is the simulation, which is crucial to learn the performance of the system in non-common situations. That is why several cases have been studied, varying the position of the coils in the three axis, and analysinghow the misalignment affects to the efficiency. This study is important, for dynamic charging testing is oneofthe targets set for this project and future work.

Outgoing

Robust Aircraft Trajectory Planning Under Wind Uncertainty Using Optimal Control

Scipedia content — Tue, 26 Jan 2021 16:14:39 +0100

Mención Internacional en el título de doctor The Air Traffic Management (ATM) system in the busiest airspaces in the world is currently being overhauled to deal with multiple capacity, socioeconomic, and environmental challenges. One major pillar of this process is the shift towards a concept of operations centered on aircraft trajectories (called Trajectory-Based Operations or TBO in Europe) instead of rigid airspace structures. However, its successful implementation (and, thus, the realization of the associated improvements in ATM performance) rests on appropriate understanding and management of uncertainty. Due to its complex socio-technical structure, the design and operations of the ATM system are heavily impacted by uncertainty, proceeding from multiple sources and propagating through the interconnections between its subsystems. One major source of ATM uncertainty is weather. Due to its nonlinear and chaotic nature, a number of meteorological phenomena of interest cannot be forecasted with complete accuracy at arbitrary lead times, which leads to uncertainty or disruption in individual air and ground operations that propagates to all ATM processes. Therefore, in order to achieve the goals of SESAR and similar programs, it is necessary to deal with meteorological uncertainty at multiple scales, from the trajectory prediction and planning processes to flow and traffic management operations. This thesis addresses the problem of single-aircraft flight planning considering two important sources of meteorological uncertainty: wind prediction error and convective activity. As the actual wind field deviates from its forecast, the actual trajectory will diverge in time from the planned trajectory, generating uncertainty in arrival times, sector entry and exit times, and fuel burn. Convective activity also impacts trajectory predictability, as it leads pilots to deviate from their planned route, creating challenging situations for controllers. In this work, we aim to develop algorithms and methods for aircraft trajectory optimization that are able to integrate information about the uncertainty in these meteorological phenomena into the flight planning process at both pre-tactical (before departure) and tactical horizons (while the aircraft is airborne), in order to generate more efficient and predictable trajectories. To that end, we frame flight planning as an optimal control problem, modeling the motion of the aircraft with a point-mass model and the BADA performance model. Optimal control methods represent a flexible and general approach that has a long history of success in the aerospace field. As a numerical scheme, we use direct methods, which can deal with nonlinear systems of moderate and high-dimensional state spaces in a computationally manageable way. Nevertheless, while this framework is well-developed in the context of deterministic problems, the techniques for the solution of practical optimal control problems under uncertainty are not as mature, and the methods proposed in the literature are not applicable to the flight planning problem as it is now understood. The first contribution of this thesis addresses this challenge by introducing a framework for the solution of general nonlinear optimal control problems under parametric uncertainty. It is based on an ensemble trajectory scheme, where the trajectories of the system under multiple scenarios are considered simultaneously within the same dynamical system and the uncertain optimal control problem is turned into a large conventional optimal control problem that can be then solved by standard, well-studied direct methods in optimal control. We then employ this approach to solve the robust flight plan optimization problem at the planning horizon. In order to model uncertainty in the wind and estimating the probability of convective conditions, we employ Ensemble Prediction System (EPS) forecasts, which are composed by multiple predictions instead of a single deterministic one. The resulting method can be used to optimize flight plans for maximum expected efficiency according to the cost structure of the airline; additionally, predictability and exposure to convection can be incorporated as additional objectives. The inherent tradeoffs between these objectives can be assessed with this methodology. The second part of this thesis presents a solution for the rerouting of aircraft in uncertain convective weather scenarios at the tactical horizon. The uncertain motion of convective weather cells is represented with a stochastic model that has been developed from the output of a deterministic satellite-based nowcast product, Rapidly Developing Thunderstorms (RDT). A numerical optimal control framework, based on the pointmass model with the addition of turn dynamics, is employed for optimizing efficiency and predictability of the proposed trajectories in the presence of uncertainty about the future evolution of the storm. Finally, the optimization process is initialized by a randomized heuristic procedure that generates multiple starting points. The combined framework is able to explore and as exploit the space of solution trajectories in order to provide the pilot or the air traffic controller with a set of different suggested avoidance trajectories, as well as information about their expected cost and risk. The proposed methods are tested on example scenarios based on real data, showing how different user priorities lead to different flight plans and what tradeoffs are then present. These examples demonstrate that the solutions described in this thesis are adequate for the problems that have been formulated. In this way, the flight planning process can be enhanced to increase the efficiency and predictability of individual aircraft trajectories, which would lead to higher predictability levels of the ATM system and thus improvements in multiple performance indicators. El sistema de gestión del tráfico aéreo (Air Traffic Management, ATM) en los espacios aéreos más congestionados del mundo está siendo reformado para lidiar con múltiples desafíos socioeconómicos, medioambientales y de capacidad. Un pilar de este proceso es el gradual reemplazo de las estructuras rígidas de navegación, basadas en aerovías y waypoints, hacia las operaciones basadas en trayectorias. No obstante, la implementación exitosa de este concepto y la realización de las ganancias esperadas en rendimiento ATM requiere entender y gestionar apropiadamente la incertidumbre. Debido a su compleja estructura socio-técnica, el diseño y operaciones del sistema ATM se encuentran marcadamente influidos por la incertidumbre, que procede de múltiples fuentes y se propaga por las interacciones entre subsistemas y operadores humanos. Uno de los principales focos de incertidumbre en ATM es la meteorología. Debido a su naturaleza no-linear y caótica, muchos fenómenos de interés no pueden ser pronosticados con completa precisión en cualquier horizonte temporal, lo que crea disrupción en las operaciones en aire y tierra que se propaga a otros procesos de ATM. Por lo tanto, para lograr los objetivos de SESAR e iniciativas análogas, es imprescindible tener en cuenta la incertidumbre en múltiples escalas espaciotemporales, desde la predicción de trayectorias hasta la planificación de flujos y tráfico. Esta tesis aborda el problema de la planificación de vuelo de aeronaves individuales considerando dos fuentes importantes de incertidumbre meteorológica: el error en la predicción del viento y la actividad convectiva. Conforme la realización del viento se desvía de su previsión, la trayectoria real se desviará temporalmente de la planificada, lo que implica incertidumbre en tiempos de llegada a sectores y aeropuertos y en consumo de combustible. La actividad convectiva también tiene un impacto en la predictibilidad de las trayectorias, puesto que obliga a los pilotos a desviarse de sus planes de vuelo para evitarla, cambiado así la situación de tráfico. En este trabajo, buscamos desarrollar métodos y algoritmos para la optimización de trayectorias que puedan integrar información sobre la incertidumbre en estos fenómenos meteorológicos en el proceso de diseño de planes de vuelo en horizontes de planificación (antes del despegue) y tácticos (durante el vuelo), con el objetivo de generar trayectorias más eficientes y predecibles. Con este fin, formulamos la planificación de vuelo como un problema de control óptimo, modelando la dinámica del avión con un modelo de masa puntual y el modelo de rendimiento BADA. El control óptimo es un marco flexible y general con un largo historial de éxito en el campo de la ingeniería aeroespacial. Como método numérico, empleamos métodos directos, que son capaces de manejar sistemas dinámicos de alta dimensión con costes computacionales moderados. No obstante, si bien esta metodología es madura en contextos deterministas, la solución de problemas prácticas de control óptimo bajo incertidumbre en la literatura no está tan desarrollada, y los métodos propuestos en la literatura no son aplicables al problema de interés. La primera contribución de esta tesis hace frente a este reto mediante la introducción de un marco numérico para la resolución de problemas generales de control óptimo no-lineal bajo incertidumbre paramétrica. El núcleo de este método es un esquema de conjunto de trayectorias, en el que las trayectorias del sistema dinámico bajo múltiples escenarios son consideradas de forma simultánea, y el problema de control óptimo bajo incertidumbre es así transformado en un problema convencional que puede ser tratado mediante métodos existentes en control óptimo. A continuación, empleamos este método para resolver el problema de la planificación de vuelo robusta. La incertidumbre en el viento y la probabilidad de ocurrencia de condiciones convectivas son modeladas mediante el uso de previsiones de conjunto o ensemble, compuestas por múltiples predicciones en lugar de una única previsión determinista. Este método puede ser empleado para maximizar la eficiencia esperada de los planes de vuelo de acuerdo a la estructura de costes de la aerolínea; además, la predictibilidad de la trayectoria y la exposición a la convección pueden ser incorporadas como objetivos adicionales. El trade-off entre estos objetivos puede ser evaluado mediante la metodología propuesta. La segunda parte de la tesis presenta una solución para reconducir aviones en escenarios tormentosos en un horizonte táctico. La evolución de las células convectivas es representada con un modelo estocástico basado en las proyecciones de Rapidly Developing Thunderstorms (RDT), un sistema determinista basado en imágenes de satélite. Este modelo es empleado por un método de control óptimo numérico, basado en un modelo de masa puntual en el que se modela la dinámica de viraje, con el objetivo de maximizar la eficiencia y predictibilidad de la trayectoria en presencia de incertidumbre sobre la evolución futura de las tormentas. Finalmente, el proceso de optimizatión es inicializado por un método heurístico aleatorizado que genera múltiples puntos de inicio para las iteraciones del optimizador. Esta combinación permite explorar y explotar el espacio de trayectorias solución para proporcionar al piloto o al controlador un conjunto de trayectorias propuestas, así como información útil sobre su coste y el riesgo asociado. Los métodos propuestos son probados en escenarios de ejemplo basados en datos reales, ilustrando las diferentes opciones disponibles de acuerdo a las prioridades del planificador y demostrando que las soluciones descritas en esta tesis son adecuadas para los problemas que se han formulado. De este modo, es posible enriquecer el proceso de planificación de vuelo para incrementar la eficiencia y predictibilidad de las trayectorias individuales, lo que contribuiría a mejoras en el rendimiento del sistema ATM. These works have been financially supported by Universidad Carlos III de Madrid through a PIF scholarship; by Eurocontrol, through the HALA! Research Network grant 10-220210-C2; by the Spanish Ministry of Economy and Competitiveness (MINECO)'s R&D program, through the OptMet project (TRA2014-58413-C2-2-R); and by the European Commission's SESAR Horizon 2020 program, through the TBO-Met project (grant number 699294). Programa de Doctorado en Mecánica de Fluidos por la Universidad Carlos III de Madrid; la Universidad de Jaén; la Universidad de Zaragoza; la Universidad Nacional de Educación a Distancia; la Universidad Politécnica de Madrid y la Universidad Rovira i Presidente: Damián Rivas Rivas.- Secretario: Xavier Prats Menéndez.- Vocal: Benavar Sridhar

Document type: Article

Infraestructure readiness for autonomous vehicles

Scipedia content — Tue, 26 Jan 2021 16:13:34 +0100

This study is aimed at identifying the major challenges in the infraestructure design, operation and maintenance to allow the implementation of Autonomous Vehicles in interurban and urban road network.

Pump Displacement Control in Steering On-Highway Commercial Vehicles

Scipedia content — Tue, 26 Jan 2021 16:10:41 +0100

div"Due to recent advances in sensor technology and the exponential increase in computation power of electronic control units (ECUs) along with their increasing affordability, active safety and vehicle automation have become major trends in the commercial vehicle industry. New regulations for increased safety are also a major driver behind the industry's increased interest in that topic. As a result, being a crucial part of vehicle automation, steering systems had to be adapted to enable Active Steering. Consequently, commercial vehicle steering designers introduced the concept of torque and angle overlay using an electric motor in series with the conventional hydraulic steering system. However, despite the fact that these systems are becoming more prevalent in the market, they still suffer from inefficiencies intrinsic to the conventional hydraulic steering system still being used. These inefficiencies are a result of"/div""div"flow metering losses due to the use of control valves to regulate the pump flow output, as well as inside the steering gear with the use control valves to build assistance pressure."/div""div""br""/div""div""div"In this research project, we investigate the potential use of the proven pump Displacement Control (DC) technology in steering on-highway commercial vehicles. DC pumps have been shown to signicantly improve system efficiency as they allow the removal of control valves typically used to regulate "/div""div"ow [1]. Instead, the displacement of the pump can be directly controlled to vary the pump's flow rate and direction,"/div""div"and thus eliminating throttling losses. The DC technology has been successfully used in a steer-by-wire conguration for an articulated frame steering vehicle and has been shown to signicantly improve efficiency and productivity, as well as result in a reduction in fuel consumption [2]."/div""/div""div""br""/div""div""div"In this work, we propose a steer-by-wire system, using DC pump technology, for on-highway commercial vehicles, and present the dierent possible congurations in which it can be implemented. Moreover, the benets and drawbacks of the steer-by-wire system are researched and identied. Subsequently, the system is designed and validated in simulation, on laboratory test setup, as well as on a test vehicle to prove its feasibility."/div""/div""div""br""/div""div""div"Chief among the drawbacks of the steer-by-wire system is potential failures that can lead to the complete loss of the steering function of the vehicle. As a result, different possible fail-safe mechanisms are researched from which the most suitable ones are proposed to allow the steer-by-wire system to fail safely. Moreover, two of the proposed fail-safe mechanism are implemented onto the test vehicle to prove and validate their feasibility."/div""/div""div""br""/div""div""div"Furthermore, an alternative way of using displacement controlled pumps for active steering is be proposed. For this concept, we investigate the possibility of actively controlling the driver's steering effort by varying the pump displacement while maintaining the mechanical link between the steering wheel and the road wheels. If successful, this method will allow for a more efficient way of providing steering assistance as it does away with the conventional control valves used to build pressure and regulate pump flow, and thus eliminating throttling losses. This method has also the advantage of having an intrinsic fail-safe mechanism with manual steering being always possible should the hydraulic or electric systems fail."/div""/div

Vehicle-To-Grid et Flexibilité pour les Réseaux d'Electricité : de la solution technique à la construction de business model

Scipedia content — Tue, 26 Jan 2021 16:10:23 +0100

Transport industry being one the first CO2 emitters, there is an urgent need to decarbonize this sector, which could be achieved by the conjunction of the electrification of the vehicles and decarbonization of the electricity generation mix. In conjunction with increasing flexibility needs to support the introduction of Renewable Energy Sources, the development of Electric Vehicles could add new constraints for System Operators if charging process is not managed in a smart way.However, considering mobility requirements, there is a flexibility in the charging pattern of the vehicles, which could be used to offer flexibility services to System Operators, using smart-charging algorithms. Moreover, this flexibility could increase with the possibility to have reverse flow from the battery to the grid.Research focused mainly, during last years, on the design of algorithms to provide services with electric vehicles, taking into account mobility needs of users. In this thesis, we try to go beyond this design of algorithms, going through the different steps to elaborate a viable business model. We focus on the provision of one service – Frequency Containment Reserve – identified as the most valuable for Electric Vehicles equipped with bidirectional chargers.; Les ventes de Véhicules Electriques ont été en constante augmentation ces dix dernières années, stimulées par l’adoption de politique publique favorisant la décarbonation du secteur automobile. Dans un contexte d’accroissement des énergies renouvelables dans le mix énergétique, entraînant des besoins plus important en flexibilité, la diffusion massive des véhicules électriques pourrait constituer une nouvelle source de contrainte pour les gestionnaire de réseaux d'électricité si la recharge n’est pas gérée de manière intelligente.La gestion de la recharge des flottes de Véhicules Electriques peut aussi constituer une opportunité pour apporter cette flexibilité, en particulier si les véhicules sont équipés de chargeurs bidirectionnels, capables de réinjecter de l’électricité dans le système pour équilibrer les réseaux.La recherche s’est principalement intéressée à la conception d’algorithmes permettant cette recharge « intelligente », qui prennent en compte les besoins en mobilité des utilisateurs, tout en fournissant différents services de flexibilité.Cette thèse s’attache à aller au-delà de l’aspect algorithmique, en balayant l’ensemble des aspects qui permettraient d’aboutir à un modèle d’affaire viable, et en se focalisant sur la fourniture d’un type de service : la réserve primaire (Frequency Containment Reserve), qui constitue le service identifié comme ayant la plus forte valeur pour des flottes de Véhicules équipés de chargeurs bidirectionnels.

Optimising load planning and container routing in intermodal rail transport

Scipedia content — Tue, 26 Jan 2021 16:07:44 +0100

Due to the geographical distance between producers and consumers, the impact of our current transport system on the environment is considerable. In an ideal, more sustainable transport system, several complementary transport modes are available, so that the most suitable route can always be selected. Because multiple transport modes and operators are involved, decision processes become more complex. That is why this research focuses on the development of innovative transport systems with realistic characteristics and planning limitations, in order to stimulate intermodal transport. Two planning tools have been developed to support decisions made by intermodal transport planners. It concerns on the one hand the integration of intermodal short and long distance routing and on the other hand the loading planning of trains. Both tools consist of fast planning algorithms that can handle realistic problem properties and can be integrated into transport management systems. The objective is to minimize transport costs and to make maximum use of available transport capacity.

Problema prático de Pollution-Routing com velocidades dependentes do horário: percepções de São Paulo.

Scipedia content — Tue, 26 Jan 2021 16:02:28 +0100

Vehicle routing problems (VRP) are one of the most studied problems in combinatorial optimization. In recent years, it has gained the attention of many researchers and business organizations not only in its classical application, but also because of the many environmental considerations that it is possible to consider. Objectives that aims to reduce fuel consumption or directly the emissions of CO2 and other greenhouse gases (GHG) have become widely adopted. Being so, many models that estimate emissions and fuel consumption have been proposed in the literature, accounting for different factors that affect fuel consumption in road transportation, such as payload, slope and travel speed. These comprehensive models, while providing very accurate results in modeling emissions and fuel consumption, are very dependent on numerous parameters and user inputs, many not easily retrievable by practitioners. In this way, a Practical Pollution-Routing Problem (PPRP) is a VRP that aims to reduce fuel consumption using simple and practical computations based on the Fuel Consumption Rate (FCR) of vehicles. Another important variant of the VRP that has also attracted recent attention is the time-dependent vehicle routing problem (TDVRP), in which the effects of congestion and travel speeds fluctuations during the day are taken into account when designing the delivery routes. A time-dependent approach to the PPRP, however, has not been found in the literature. Thus, our research addresses this gap and aims to propose a new variant of this problem called the Practical Pollution-Routing Problem with Time-Dependent speeds (PPRP-TD), as it has important value to practitioners interested in the reduction of fuel consumption and the hazardous effects caused by diesel trucks. We propose several instance problems based on real operations of a major retailer company that distributes in São Paulo, and also analyze the time dependent speeds of the São Paulo network. To solve both the PPRP and the PPRP-TD, we propose the GRASP-FESA solution method, which is an FCR-based Extended Savings Algorithm (FESA) combined with a Greedy Randomized Adaptive Search Procedure (GRASP) metaheuristic. In the case of the PPRP-TD, we also perform an extensive time-dependent scheduling for all given routes. The method is able to provide good results, although being computationally expensive in the case of large instances. Problemas de roteirização de veículos (VRP) são alguns dos mais estudados problemas na otimização combinatória. Recentemente, pesquisadores e organizações também tem prestado atenção não apenas em suas aplicações clássicas, mas também nas muitas considerações ambientais que podem ser consideradas. Objetivos que buscam reduzir o consumo de combustíveis fósseis e a emissão de gases do efeito estufa tem sido amplamente utilizados. Assim sendo, diversos modelos para estimar as emissões de gases poluentes e consumo de combustível vem sendo propostos, considerado diversos fatores que influenciam no consumo de combustível, como a carga transportada, inclinação da via e velocidade de tráfego. Esses modelos compreensivos, embora forneçam resultados bem precisos na modelagem de emissões e consumo de combustível, são muito dependentes de uma grande quantidade de parâmetros e entradas dos usuários, sendo que muitos não são facilmente obtidos. Dessa forma, um Problema de Pollution-Routing Prático é um VRP que busca reduzir o consumo de combustível usando cálculos simplificados para o consumo de combustível, baseados na taxa de consumo de combustível de diferentes classes de veículos. Outra importante variante do VRP é o VRP dependente do horário, em que os efeitos de congestionamento e velocidades de tráfego flutuantes ao longo do dia são considerados ao se construir as rotas de entrega. Entretanto, uma abordagem ao PPRP com velocidades dependentes do horário não foi encontrada na literatura. Portanto, nossa pesquisa endereça esta lacuna e busca propor uma nova variante deste problema, chamado Problema de Pollution-Routing Prático com velocidades Dependentes do Horário (PPRP-TD), devido ao importante valor para empresas e praticantes interessados em reduzir o consumo de combustível de suas frotas, assim como os graves efeitos causados ao ambiente por veículos movidos a combustíveis fósseis. São propostas diversas instâncias baseadas nas operações reais de um grande varejista em São Paulo, além de uma análise das velocidades deptendentes do horário na rede de São Paulo. Para resolver tanto o PPRP quanto o PPRP-TD, é proposto o método de solução GRASP-FESA, que é um FCR-based Extended Savings Algorithm (FESA) combinado com a metaheurística GRASP (Greedy Randomized Adaptive Search procedure). No caso do PPRP-TD, também é realizada uma programação extensiva dependente do horário para todas as rotas. O método é capaz de obter bons resultados, embora seja computacionalmente caro no caso de grandes instâncias.

Demand-side managment. Key to decarbonization

Scipedia content — Tue, 26 Jan 2021 15:58:47 +0100

Decarbonization is one of the biggest challenges of our time. The European Union, as other organizations have already designed the strategies to achieve a more sustainable future. The integration of renewable energy sources is not a technical challenge anymore. However, due to the variability of these type of technologies some actions should be implemented so the conventional ones are not needed any more. One crucial solution is the implementation of demand side management actions which focus on controlling the demand rather than the generation. This thesis identifes the diferent actions on diferent demand side management actions and their performance in Spain. Also, an analysis regarding implemented policies in other European countries is performed to identify successful actions that could be later implemented in Spain. Ingeniería de la Energí

Contributions to sustainable urban transport : decision support for alternative mobility and logistics concepts

Scipedia content — Tue, 26 Jan 2021 15:58:30 +0100

Increasing transport activities in cities are a substantial driver for congestion and pollution, influencing urban populations’ health and quality of life. These effects are consequences of ongoing urbanization in combination with rising individual demand for mobility, goods, and services. With the goal of increased environmental sustainability in urban areas, city authorities and politics aim for reduced traffic and minimized transport emissions. To support more efficient and sustainable urban transport, this cumulative dissertation focuses on alternative transport concepts. For this purpose, scientific methods and models of the interdisciplinary information systems domain combined with elements of operations research, transportation, and logistics are developed and investigated in multiple research contributions. Different transport concepts are examined in terms of optimization and acceptance to provide decision support for relevant stakeholders. In more detail, the overarching topic of urban transport in this dissertation is divided into the complexes urban mobility (part A) in terms of passenger transport and urban logistics (part B) with a focus on the delivery of goods and services. Within part A, approaches to carsharing optimization are presented at various planning levels. Furthermore, the user acceptance of ridepooling is investigated. Part B outlines several optimization models for alternative urban parcel and e-grocery delivery concepts by proposing different network structures and transport vehicles. Conducted surveys on intentional use of urban logistics concepts give valuable hints to providers and decision makers. The introduced approaches with their corresponding results provide target-oriented support to facilitate decision making based on quantitative data. Due to the continuous growth of urban transport, the relevance of decision support in this regard, but also the understanding of the key drivers for people to use certain services will further increase in the future. By providing decision support for urban mobility as well as urban logistics concepts, this dissertation contributes to enhanced economic, social, and environmental sustainability in urban areas.

Estimativa do volume de passageiros ao longo de uma linha de transporte público por ônibus a partir da geoestatística

Scipedia content — Tue, 26 Jan 2021 15:55:43 +0100

A modelagem clássica da demanda por transportes ignora um importante aspecto normalmente presente na estrutura das variáveis de interesse: a autocorrelação espacial. Pesquisas recentes reconhecem e incluem tal característica à estimativa da demanda, mas há limitações referentes aos elementos básicos de tratamento utilizados nas abordagens. No intuito de superar alguns problemas e restrições associados aos estudos anteriores, o presente trabalho se valeu da dependência espacial entre as observações de Embarques e Desembarques, por ponto de parada, e Carregamento nos trechos, ao longo de uma linha de transporte público, a fim de gerar estimativas dessas variáveis em pontos e trechos que não seriam amostrados por ocasião da pesquisa sobe/desce. Tal previsão foi realizada por meio da aplicação de Krigagem Ordinária a uma linha de ônibus da cidade de São Paulo, Brasil. Os resultados obtidos confirmaram a adequabilidade do ferramental geoestatístico à estimativa de variáveis de demanda por transportes ao longo de uma linha de ônibus.

Document type: Doctoral thesis

Transition Towards Fixed-Line Autonomous Bus Transportation Systems

Scipedia content — Tue, 26 Jan 2021 15:55:17 +0100

In the last years the steady development of autonomous driving technology has enabled the deployment of more mature autonomous vehicles. These vehicles have been applied in several pilot projects worldwide, most commonly in the form of small buses. At the same time, the amount of people traveling in especially urban areas is continuously growing, resulting in more trips in the transportation system. An efficient transportation system is therefore required to serve the growing passenger demand. Autonomous buses (AB) are assumed to have lower operational costs and with that public transport (PT) systems can potentially be designed more efficiently to facilitate the increased demand better. In this study, an AB specific simulation-based optimization framework is proposed which allows analyzing the impacts AB have on line-based PT systems. The thesis focuses on the transition from existing PT systems towards line-based PT systems operated partially or exclusively by AB. Existing work on PT service design is extended so that realistic AB systems can be investigated. This is achieved by (i) using AB specific operator cost formulations, (ii) integrating infrastructure costs required for AB operations, (iii) utilizing a dynamic, stochastic and schedule-based passenger assignment model for the simulation of PT networks and by (iv) formulating a multi-objective optimization problem allowing to investigate the stakeholder-specific impacts of AB. In Paper I the effects of AB, concerning service frequency and vehicle capacity, on fixed-line PT networks are investigated. Among other metrics, the changes are evaluated based on differences in level of service and passenger flow. Additionally, the sequential introduction of AB in existing PT systems is studied. The framework addresses a case study in Kista, Sweden. The study confirmed the initial hypothesis that the deployment of AB leads to an increase in service frequency and a marginal reduction in vehicle capacity. Furthermore, it could be seen that the deployment of AB increases the passenger load on AB lines and that passengers can shift from other PT modes towards the AB services. Paper II incorporates a multi-objective heuristic optimization algorithm in the simulation framework. The study investigates changes in transport network design based on the deployment of AB. The differences in user-focused and operator-focused network design are analyzed and the impact of AB on these is quantified. This study is applied to a case study in Barkarby, Sweden where a full-sized, line-based PT network is designed to exclusively operate AB. Among other findings, we show that the autonomous technology reduces the number of served bus stops and reduces the total PT network size. Additionally, average passenger waiting time can be reduced when deploying AB on user-focused PT networks, which in turn leads to a further reduction of user cost. De senaste årens framsteg inom autonom körteknik har lett till mer mogna autonoma fordon. Dessa fordon har setts tillämpas i flera pilotprojekt över hela världen, oftast i form av små bussar. Samtidigt växer mängden människor som reser, särskilt i stadsområden, kontinuerligt vilket resulterar i fler resor i transportsystemet. Därför krävs ett effektivt transportsystem för att tillgodose det växande antalet passagerare. Autonoma bussar (AB) antas ha lägre driftskostnader och därmed kan system för kollektivtrafik (public transport, PT) potentiellt utformas mer effektivt för att underlätta den ökade efterfrågan bättre. I denna studie föreslås ett AB-specifikt simuleringsbaserat optimeringsramverk som gör det möjligt att analysera effekterna AB har på linjebaserade PT-system. Avhandlingen fokuserar på övergången från befintliga PT-system till linjebaserade PT-system som delvis eller uteslutande drivs av AB. Befintligt arbete med PT-tjänstdesign utvidgas så att realistiska AB-system kan undersökas. Detta uppnås genom att (i) använda AB-specifika operatörskostnadsformuleringar, (ii) integrera infrastrukturkostnader som krävs för AB-verksamhet, (iii) använda en dynamisk, stokastisk och schemabaserad modell för att tilldela passagerare vid simulering av PT-nät samt genom att (iv) formulera ett multifunktionellt optimeringsproblem som gör det möjligt att undersöka AB: s intressespecifika effekter. I artikel I undersöks effekterna av AB, med avseende på servicefrekvens och fordonskapacitet, på fasta linjer i PT-nät. Förändringar utvärderas bland annat utifrån skillnader i servicenivå och passagerarflöde. Dessutom studeras den sekventiella introduktionen av AB i befintliga PT-system. Det föreslagna ramverket tillämpas på en fallstudie i Kista, Sverige. Studien bekräftade den initiala hypotesen att utplaceringen av AB leder till en ökning av servicefrekvensen och en marginell minskning av fordonens kapacitet. Vidare kunde man se att utplaceringen av AB ökar passagerarbelastningen på AB-linjer och att passagerare kan skifta från andra PT-former mot AB-tjänsterna. Artikel II integrerar en multifunktionell heuristisk optimeringsalgoritm i ramverket för simuleringen. Studien undersöker förändringar i transportnätverkets design baserat på implementeringen av AB. Skillnaderna i användarfokuserad och operatörsfokuserad nätverksdesign analyseras och AB: s inverkan på dessa kvantifieras. Denna studie tillämpas på en fallstudie i Barkarby, Sverige, där ett fullstort linjebaserat PT-nät är utformat för att exklusivt driva AB. Vi visar bland annat att den autonoma tekniken reducerar antalet använda busshållplatser och reducerar den totala PT-nätstorleken. Dessutom kan implementeringen av AB på användarfokuserade PT-nät ytterligare förbättra servicenivån främst genom att minska den genomsnittliga väntetiden per passagerare.

Mining Human Mobility Data and Social Media for Smart Ride Sharing

Scipedia content — Tue, 26 Jan 2021 15:53:16 +0100

CAPES People living in highly-populated cities increasingly suffer an impoverishment of their quality of life due to pollution and traffic congestion problems caused by the huge number of circulating vehicles. Indeed, the reduction the number of circulating vehicles is one of the most difficult challenges in large metropolitan areas. This PhD thesis proposes a research contribution with the final objective of reducing travelling vehicles. This is done towards two different directions: on the one hand, we aim to improve the efficacy of ride sharing systems, creating a larger number of ride possibilities based on the passengers destination activities; on the other hand, we propose a social media analysis method, based on machine learning, to identify transportation demand to an event. Concerning the first research direction, we investigate a novel approach to boost ride sharing opportunities based, not only on fixed destinations, but also on alternative destinations while preserving the intended activity of the user. We observe that in many cases the activity motivating the use of a private car (e.g., going to a shopping mall) can be performed at many different locations (e.g. all the shopping malls in a given area). Our assumption is that, when there is the possibility of sharing a ride, people may accept visiting an alternative destination to fulfill their needs. Based on this idea, We thus propose Activity-Based Ride Matching (ABRM), an algorithm aimed at matching ride requests with ride offers to alternative destinations where the intended activity can still be performed. By analyzing two large mobility datasets, we found that with our approach there is an increase up to 54.69% in ride-sharing opportunities compared to a traditional fixed-destination-oriented approach. For the second research contribution, we focus on the analysis of social media for inferring the transportation demands for large events such as music festivals and sports games. In this context, we investigate the novel problem of exploiting the content of nongeotagged posts to infer users’ attendance of large events. We identified three temporal periods: before, during and after an event. We detail the features used to train the event attendance classifiers on the three temporal periods and report on experiments conducted on two large music festivals in the UK. Our classifiers attained a very high accuracy, with the highest result observed for Creamfields festival (∼91% accuracy to classify users that will participate in the event). Furthermore, we proposed an example of application of our methodology in event-related transportation. This proposed application aims to evaluate the geographic areas with a higher potential demand for transportation services to an event. Pessoas que vivem em cidades altamente populosas sofrem cada vez mais com o declínio da qualidade de vida devido à poluição e aos problemas de congestionamento causados pelo enorme número de veículos em circulação. A redução da quantidade de veículos em circulação é de fato um dos mais difíceis desafios em grandes áreas metropolitanas. A presente tese de doutorado propõe uma pesquisa com o objetivo final de reduzir o número de veículos em circulação. Tal objetivo é feito em duas diferentes direções: por um lado, pretendemos melhorar a eficácia dos sistemas de ride-sharing aumentando o número de possibilidades de caronas com base na atividade destino dos passageiros; por outro lado, propomos também um método baseado em aprendizagem de máquina e análise de mídia social para identificar demanda de transporte de um evento. Em relação à primeira contribuição da pesquisa, nós investigamos uma nova abordagem para aumentar o compartilhamento de caronas baseando-se não apenas em destinos fixos, mas também em destinos alternativos enquanto que preservando a atividade pretendida do usuário. Observamos que em muitos casos a atividade que motiva o uso de um carro particular (por exemplo ir a um shopping center) pode ser realizada em muitos locais diferentes (por exemplo todos os shoppings em uma determinada área). Nossa suposição é que, quando há a possibilidade de compartilhar uma carona, as pessoas podem aceitar visitas a destinos alternativos para satisfazer suas necessidades. Nós propomos o Activity-Based Ride Matching (ABRM), um algoritmo que visa atender às solicitações de caronas usando destinos alternativos onde a atividade pretendida pelo passageiro ainda pode ser executada. Através da análise de dois grande conjuntos de dados de mobilidade, mostramos que nossa abordagem alcança um aumento de até 54,69% nas oportunidades de caronas em comparação com abordagens tradicionais orientadas a destinos fixos. Para a segunda contribuição nos concentramos na análise de mídias sociais para inferir as demandas de transporte para grandes eventos tais como concertos musicais e eventos esportivos. Investigamos um problema que consiste em explorar o conteúdo de postagens não geolocalizadas para inferir a participação dos usuários em grandes eventos. Nós identificamos três períodos temporais: antes, durante e depois de um evento. Detalhamos as features usadas para treinar classificadores capazes de inferir a participação de usuários em um dado evento nos três períodos temporais. Os experimentos foram conduzidos usando postagens em mídias sociais referentes a dois grandes festivais de música no Reino Unido. Nossos classificadores obtiveram alta accuracy, com o maior resultado observado para o festival Creamfields (∼91% de accuracy para classificar os usuários que participarão do evento). Propusemos também uma aplicação de nosso método que visa avaliar as áreas geográficas com maior potencial de demanda por serviços de transporte para um evento. Le persone che vivono in città densamente popolate subiscono sempre più un impoverimento delle loro qualità della vita a causa dell’inquinamento e dei problemi di congestione del traffico causati dall’enorme numero di veicoli circolanti. La riduzione dei veicoli circolanti è una delle sfide più difficili nelle grandi aree metropolitane. Questa tesi di dottorato propone un contributo di ricerca con l’obiettivo finale di ridurre i numeri di veicoli in viaggio. Questo eśtato sviluppato verso due direzioni: da un lato, vogliamo migliorare l’efficacia dei sistemi di ride sharing, aumentando la possibilità di ricevere e dare passaggi in base alla attività di destinazione dei passeggeri. D’altra parte, vogliamo proporre un metodo basato sul machine learning e analisi dei social media, per identificare demanda de transporte a un evento. Per quanto riguarda il primo contributo di ricerca, abbiamo studiato un nuovo approccio per aumentare la condivisione dei passagi non solo su destinazioni fisse, ma anche su destinazioni alternative preservando l’attività prevista dall’utente. Osserviamo infatti che in molti casi l’attività che motiva l’uso di un’auto privata (ad es. andare in un centro commerciale) può essere eseguito in molti luoghi diversi (ad esempio tutti i centri commerciali in una determinata area). La nostra ipotesi è che, quando c’è la possibilità di condividere un passaggio, le persone possono accettare di visitare una destinazione alternativa per soddisfare i loro bisogni. Basato su questa idea, proponiamo Activity-Based Ride Matching (ABRM), un algoritmo che mira a soddisfare le richieste di carpool utilizzando destinazioni alternative, dove l’attività desiderata dal passeggero può ancora essere eseguita. Attraverso l’analisi di due grandi insiemi di dati di mobilità, mostriamo che il nostro approccio raggiunge un aumento fino al 54,69% nelle opportunità di condivisione di car pooling rispetto agli approcci tradizionali rivolti a destinazioni fisse. Per il secondo contributo della ricerca ci concentriamo sull’analisi dei social media per inferire le richieste di trasporto verso grandi eventi come concerti musicali e giochi sportivi. In questo contesto, indaghiamo sul nuovo problema dello sfruttamento del contenuto di non geotagged post per inferire la presenza di utenti a grandi eventi. Abbiamo identificato tre periodi temporali: prima, durante e dopo un evento. Descriviamo in dettaglio le caratteristiche utilizzate per addestrare i classificatori per inferire la partecipazione all’evento sui tre periodi temporali. Riportiamo gli esperimenti condotti su due grandi festival musicali nel Regno Unito. I nostri classificatori raggiungono uma alta accuracy, con il risultato più alto osservato per il festival Creamfields (∼91% di accuracy per classificare gli utenti che parteciperanno all’evento). Inoltre, abbiamo proposto un’applicazione della nostra metodologia che ha come scopo valutare le aree geografiche con il maggior potenziale di domanda di servizi di trasporto per un evento.

Document type: Conference object

Probabilistic Motion Planning for Automated Vehicles

Scipedia content — Tue, 26 Jan 2021 15:52:10 +0100

This thesis targets the problem of motion planning for automated vehicles. As a prerequisite for their on-road deployment, automated vehicles must show an appropriate and reliable driving behavior in mixed traffic, i.e. alongside human drivers. Besides the uncertainties resulting from imperfect perception, occlusions and limited sensor range, also the uncertainties in the behavior of other traffic participants have to be considered. Related approaches for motion planning in mixed traffic often employ a deterministic problem formulation. The solution of such formulations is restricted to a single trajectory. Deviations from the prediction of other traffic participants are accounted for during replanning, while large uncertainties lead to conservative and over-cautious behavior. As a result of the shortcomings of these formulations in cooperative scenarios and scenarios with severe uncertainties, probabilistic approaches are pursued. Due to the need for real-time capability, however, a holistic uncertainty treatment often induces a strong limitation of the action space of automated vehicles. Moreover, safety and traffic rule compliance are often not considered. Thus, in this work, three motion planning approaches and a scenario-based safety approach are presented. The safety approach is based on an existing concept, which targets the guarantee that automated vehicles will never cause accidents. This concept is enhanced by the consideration of traffic rules for crossing and merging traffic, occlusions, limited sensor range and lane changes. The three presented motion planning approaches are targeted towards the different predominant uncertainties in different scenarios, while operating in a continuous action space. For non-interactive scenarios with clear precedence, a probabilistic approach is presented. The problem is modeled as a partially observable Markov decision process (POMDP). In contrast to existing approaches, the underlying assumption is that the prediction of the future progression of the uncertainty in the behavior of other traffic participants can be performed independently of the automated vehicle's motion plan. In addition to this prediction of currently visible traffic participants, the influence of occlusions and limited sensor range is considered. Despite its thorough uncertainty consideration, the presented approach facilitates planning in a continuous action space. Two further approaches are targeted towards the predominant uncertainties in interactive scenarios. In order to facilitate lane changes in dense traffic, a rule-based approach is proposed. The latter seeks to actively reduce the uncertainty in whether other vehicles willingly make room for a lane change. The generated trajectories are safe and traffic rule compliant with respect to the presented safety approach. To facilitate cooperation in scenarios without clear precedence, a multi-agent approach is presented. The globally optimal solution to the multi-agent problem is first analyzed regarding its ambiguity. If an unambiguous, cooperative solution is found, it is pursued. Still, the compliance of other vehicles with the presumed cooperation model is checked, and a conservative fallback trajectory is pursued in case of non-compliance. The performance of the presented approaches is shown in various scenarios with intersecting lanes, partly with limited visibility, as well as lane changes and a narrowing without predefined right of way.

Go-to-market strategy for mov.E

Scipedia content — Tue, 26 Jan 2021 15:44:57 +0100

While the electric vehicle market is growing more than ever, it is expected to slow down in the 2030s due to one major issue that is capable of decelerating its current strong growth and expansion – charging infrastructure constraints. They arise due to the fact that the existing electricity grid will not be able to accommodate the increasing demand in high density areas where charging opportunities are limited and the number of electric vehicles high. mov.e has created a digital sharing platform, that provides the base for the first collective electric vehicle charging system, and is connected to its IoT smart plugs, which simply replace existing standard sockets. After having been able to work on its idea with industry experts as part of an intensive 10-week incubation program in Silicon Valley, the team behind mov.e has not only received enough positive feedback that its solution is in high demand and technically proving its potential to speed up the electric mobility revolution, but has also decided on the business model behind its idea. It is now at the stage of finalizing its prototype. Until then, mov.e needs to figure out how it can best penetrate the market and how it can effectively deliver its solution to the end customer to eventually disrupt the way of charging electric vehicles and to provide the ground for an electric vehicle full-scale adoption for the years ahead.