Scipedia: Documents published in 2011

Green and Ecological Technologies for Urban Planning

Scipedia content — Mon, 25 Jan 2021 12:44:34 +0100

This book discusses the social, technological, and ecological impediments faced in the smart urban design and planning of communities with the use of eco-technologies â from green areas to municipal applications, and from sustainable land use to transportation â highlighting resilience. Topics covered include urban and transportation planning, geographic information systems, economic and ecological challenges in cities, intelligent transportation systems, sustainable transportation, smart cities, urban resilience, and energy efficient design.

Unlocking the Public-Private Partnerships Deadlock in Indonesia

Scipedia content — Mon, 25 Jan 2021 12:44:08 +0100

The challenges faced by Indonesia in creating a robust Public-Private Partnership (PPP) program are similar to those faced by many other middle-income countries. This paper provides a gap analysis for Indonesia's PPP framework based on lessons learned and good practice from countries with successful PPP programs. It identifies, in particular, the need for the government to: select good projects for PPP, rather than only complex ones that are less likely to attract private partners. Establish a list of projects by a limited cabinet meeting and stick to it-issuing different lists of projects and holding showcase summits with open agendas tends to confuse the market. Keep those projects on track for PPP-allowing the contracting agencies to develop prospective projects directly, or to award them without competition leads investors to question the commitment and resolve of the government to its own PPP process. Prepare projects well, using the Ministry of Finance to provide access to: 1) a team of PPP experts to help contracting agencies develop projects; 2) project preparation funding to help pay the high costs of preparation; and 3) viability gap funding to make projects more affordable and bankable by defraying some of the capital costs.

Document type: Book

Traffic engineering approaches using multicriteria optimization techniques

Scipedia content — Mon, 25 Jan 2021 12:42:20 +0100

Part 2: Performance and Simulation Analysis; International audience; Nowadays, network planning and management tasks can be of high complexity, given the numerous inputs that should be considered to effectively achieve an adequate configuration of the underlying network. This paper presents an optimization framework that helps network administrators in setting the optimal routing weights of link state protocols according to the required traffic demands, contributing in this way to improve the service levels quality provided by the network infrastructure. Since the envisaged task is a NP-hard problem, the framework resorts to Evolutionary Computation as the optimization engine. The focus is given to the use of multi-objective optimization approaches given the flexibility they provide to network administrators in selecting the adequate solutions in a given context. Resorting to the proposed optimization framework the administrator is able to automatically obtain highly optimized routing configurations adequate to support the requirements imposed by their customers. In this way, this novel approach effectively contributes to enhance and automate crucial network planning and management tasks.

Document type: Part of book or chapter of book

A Multi-Agent Simulation of Collaborative Air Traffic Flow Management

Scipedia content — Mon, 25 Jan 2021 12:39:40 +0100

Todayâs air traffic management system is not expected to scale to the projected increase in traffic over the next two decades. Enhancing collaboration between the controllers and the users of the airspace could lessen the impact of the resulting air traffic flow problems. The authors summarize a new concept that has been proposed for collaborative air traffic flow management, the problems it is meant to address, and our approach to evaluating the concept. The authors present their initial simulation design and experimental results, using several simple route selection strategies and traffic flow management approaches. Though their model is still in an early stage of development, these results have revealed interesting properties of the proposed concept that will guide their continued development, refinement of the model, and possibly influence other studies of traffic management elsewhere. Finally, they conclude with the challenges of validating the proposed concept through simulation and future work.

Traffic Measurements for Link Dimensioning: A Case Study

Scipedia content — Mon, 25 Jan 2021 12:39:17 +0100

Traditional traffic measurements meter throughput on time scales in the order of 5 minutes, e.g., using the Multi Router Traffic Grapher (MRTG) tool. The time scale on which users and machines perceive Quality of Service (QoS) is, obviously, orders of magnitudes smaller. One of many possible reasons for degradation of the perceived quality, is congestion on links along the path network packets traverse. In order to prevent quality degradation due to congestion, network links have to be dimensioned in such a way that they appropriately cater for traffic bursts on time scales similarly small to the time scale that determines perceived QoS. It is well-known that variability of link load on small time scales (e.g., 10 milliseconds) is larger than on large time scales (e.g., 5 minutes). Few quantitative figures are known, however, about the magnitude of the differences between fine and coarse-grained measurements. The novel aspect of this paper is that it quantifies the differences in measured link load on small and large time scales. The paper describes two case studies. One of the surprising results is that, even for a network with 2000 users, the difference between short-term and long-term average load can be more than 100%. This leads to the conclusion that, in order to prevent congestion, it may not be sufficient to use the 5 minute MRTG maximum and add a small safety margin.

Rethinking Sustainable Development

Scipedia content — Mon, 25 Jan 2021 12:31:01 +0100

Public transport is one of the key promoters of sustainable transport. To encourage and increase public transport patronage it is important to investigate the route choice behaviours of urban public transit users. This chapter reviews the main developments of modelling urban public transit users' route choice behaviours in a historical perspective, from the 1960s to the present time. The approaches reviewed for this study include the early heuristic studies on finding the least-cost transit route and all-or-nothing transit assignment, the bus common lines problem, the disaggregate discrete choice models, the deterministic and stochastic user equilibrium transit assignment models, and the recent dynamic transit assignment models. This chapter also provides an outlook for the future directions of modelling transit users' route choice behaviours. Through the comparison with the development of models for motorists' route choice and traffic assignment problems, this chapter advocates that transit route choice research should draw inspiration from the research outcomes from the road area, and that the modelling practice of transit users' route choice should further explore the behavioural complexities.

Chapter 15. Road transport: the biggest chunk

Scipedia content — Mon, 25 Jan 2021 12:21:08 +0100

Part Three. Mobility in a low-carbon society; With 10.7% of global GHG emissions and 17.0% of global CO2 emissions from fuel combustion in 2005 (ITF, 2010), road transport is a key component of the transport sector's commitment to mitigating its impact on climate. While there is no silver bullet that will provide sufficient abatement given the scale of the effort needed in this complex sector, a review of existing and emerging low-carbon solutions reveals a range of promising levies. Long ignored by carbon pricing mechanisms, the sector will certainly see its emissions abatement furthered by the growing number of carbon pricing initiatives targeted at it. This chapter outlines the global trends of greenhouse gas emissions in the road transport sector and suggests a segmented analysis for those emissions. It then reviews technological, organizational and behavioural solutions for emissions reduction in road transport. Finally, it assesses the potential impacts of economic instruments and other public policies related to carbon emissions reduction, giving a feedback on existing carbon pricing experience in road transport.

Can Volunteered Geographic Information Be a Participant in eEnvironment and SDI?

Scipedia content — Mon, 25 Jan 2021 12:16:01 +0100

Part 2: eEnvironment and Cross-Border Services in Digital Agenda for Europe; International audience; We investigate the potential role Volunteered Geographic Information (VGI) can play in eEvironment and various Spatial Data Infrastructures (SDI) on a local, regional, and national level. eEnvironment is the use and promotion of ICT for the purposes of environmental assessment and protection, spatial planning, and the sustainable use of natural resources. An SDI provides an institutionally sanctioned, automated means for posting, discovering, evaluating, and exchanging geospatial information by participating information producers and users. A key common theme shared by both definitions is public participation and user-centric services. We pose the research question: is VGI (an example of public participation and collaboration) is ready to participate in eEnvironment and SDI?

Document type: Part of book or chapter of book

The Role of Non-Recurring Congestion in Massive Hurricane Evacuation Events

Scipedia content — Mon, 25 Jan 2021 12:11:26 +0100

The response to a potential disaster can require the evacuation of personnel from a specified area. Generally, such efforts are restricted to the orderly mass departure of individuals across pre-planned and well maintained transportation routes. In the U.S., evacuations of up to 1,000 subjects take place every two to three weeks, with more extreme evacuations involving two million or more every one to three years (TRB, 2008). While evacuation routes are designed to accommodate normal traffic movements, congestion and gridlock can occur as the design capacity of the road system is overwhelmed by the magnitude of vehicles leaving the affected area. The resulting traffic patterns affect the safety and mobility of subjects moving to more secure areas. Adding to this disarray, potential nonrecurring incidents congest traffic patterns even more. Estimates indicate that between fifty and sixty-five percent of traffic congestion is caused by non-recurring traffic incidents with an additional ten percent related to construction and weather (Coifman, 2007). A non-recurring traffic incident is any event that both causes a reduction of roadway capacity, or an abnormal increase in demand, and requires first responders to be dispatched. Stalled vehicles, roadway debris, spilled loads, and crashes fall into this category of incidents. Non-recurring traffic incidents can cause secondary traffic incidents. These incidents further congest the traffic stream and cause delays in clean-up efforts by first-responders. Studies indicate that twenty percent of traffic incidents are secondary incidents, with one out of five resulting in a fatality. In addition to crashes, secondary incidents can include overheated vehicles, out of fuel conditions, and engine stalls. The delay and traffic gridlock associated with traffic incidents is compounded during the evacuation process due to the large numbers of subjects leaving the affected area. These delays and backups result in: â¢ Increased response time by first responders â¢ Lost time resulting in a wider evacuation window â¢ Increased fuel consumption â¢ Reduced air quality and other adverse environmental conditions â¢ Increased potential for more serious secondary incidents resulting from rear end collisions, traffic exiting the route, or exiting to the shoulder of the road â¢ Increased potential of crashes by incidents involving personnel responding to traffic incidents â¢ Negative public image of first responders involved in incident management activities.

A Guidebook for Sustainability Performance Measurement for Transportation Agencies

Scipedia content — Mon, 25 Jan 2021 12:07:16 +0100

Transportation agencies such as state departments of transportation often struggle to understand, measure, and apply sustainability concepts in their core activities. This paper describes research performed under the National Cooperative Highway Research Program entitled, âSustainability Performance Measures for State Departments of Transportation and Other Transportation Agencies,â which developed guidance for transportation agencies to understand, quantify and apply concepts of sustainability through performance measurement. A flexible, generally applicable framework was developed to provide transportation agencies with the tools required to apply sustainability in a holistic manner through performance measurement. The framework assists an agency in the understanding of sustainability, directs an agency toward the practical implementation of sustainability through performance measurement, and encourages the coordination with partner agencies and stakeholders. The research also covered the various types of applications of sustainability performance measures, and identifies specific examples and case studies, tools, and approaches to applying sustainability. It details how transportation agencies can take a practical, phased approach to implementing performance measurement for sustainability, taking into account the resources available. The authors also provide a âsustainability checklistâ to ensure that the framework application is consistent with the basic principles of sustainability. This research culminated in a guidebook to give transportation agencies the information and resources needed to successfully tailor and implement a sustainability performance measurement system to meet their specific needs.

The LDACS1 Physical Layer Design

Scipedia content — Mon, 25 Jan 2021 12:05:09 +0100

The legacy DSB-AM (Double Sideband Amplitude Modulation) system used for todayâs voice communication in the VHF-band is far away of meeting the demands of increasing air traffic and associated communication load. The introduction of VDL (VHF Digital Link) Mode 2 in Europe has already unfolded the paradigm shift from voice to data communication. Legacy systems, such as DSB-AM and VDL Mode 2 are expected to continue to be used in the future. However, they have to be supplemented in the near future by a new data link technology mainly for two reasons. First, only additional communication capacity can solve the frequency congestion and accommodate the traffic growth expected within the next 10-20 years in all parts of European airspace (ICAO-WGC, 2006). Second, the modernization of the Air Traffic Management (ATM) system as performed according to the SESAR (http://www.sesarju.eu/) and NextGen (http://www.faa.gov/nextgen/) programs in Europe and the US, respectively, heavily relies on powerful data link communications which VDL Mode 2 is unable to support. Based on the conclusions of the future communications study (Budinger, 2011), the ICAO Working Group of the Whole (ICAO-WGW, 2008) has foreseen a new technology operating in the L-band as the main terrestrial component of the Future Communication Infrastructure (FCI) (Fistas, 2011) for all phases of flight. Hence, such L-band technology shall meet the future ATM needs in the en-route and the Terminal Manoeuvring Area (TMA) flight domains as well as within airports. The latter application area will be supplemented by the AeroMACS technology at many large airports (Budinger, 2011). A final choice of technology for the L-band has not been made yet. Within the future communications study, various candidate technologies were considered and evaluated. However, it was found that none of the considered technologies could be fully recommended before the spectrum compatibility between the proposed systems and the legacy systems has been proven. This will require the development of prototypes for testing in a real environment against operational legacy equipment. The future communications study has identified two technology options for the L-band Digital Aeronautical Communication System (LDACS) as the most promising candidates for meeting the requirements on a future aeronautical data link. The first option, named LDACS1, is a Frequency-Division Duplex (FDD) configuration utilizing Orthogonal Frequency-Division Multiplexing (OFDM), a highly efficient multi-carrier modulation technique which enables the use of higher-order modulation schemes and Adaptive Coding and Modulation (ACM). OFDM has been adopted for current and future mobile radio communications technologies,

Path to Success

Scipedia content — Mon, 25 Jan 2021 12:00:39 +0100

The current case examines the management strategies of a leading furniture company that started off as a small business and rapidly expanded globally. The success the company has achieved through its innovative marketing strategies and use of international management techniques is presented. The case highlights the companyâs flexibility in adapting its organizational structures to the nature of the market in different countries, and its reliance on a cross-cultural management approach to marketing in order to increase product acceptance by consumers across the world.

Address-Event Based Stereo Vision with Bio-Inspired Silicon Retina Imagers

Scipedia content — Mon, 25 Jan 2021 11:54:42 +0100

Several industry, home, or automotive applications need 3D or at least range data of the observed environment to operate. Such applications are, e.g., driver assistance systems, home care systems, or 3D sensing and measurement for industrial production. State-of-the-art range sensors are laser range finders or laser scanners (LIDAR, light detection and ranging), time-of-flight (TOF) cameras, and ultrasonic sound sensors. All of them are embedded, which means that the sensors operate independently and have an integrated processing unit. This is advantageous because the processing power in the mentioned applications is limited and they are computationally intensive anyway. Another benefits of embedded systems are a low power consumption and a small form factor. Furthermore, embedded systems are full customizable by the developer and can be adapted to the specific application in an optimal way. A promising alternative to the mentioned sensors is stereo vision. Classic stereo vision uses a stereo camera setup, which is built up of two cameras (stereo camera head), mounted in parallel and separated by the baseline. It captures a synchronized stereo pair consisting of the left cameraâs image and the right cameraâs image. The main challenge of stereo vision is the reconstruction of 3D information of a scene captured from two different points of view. Each visible scene point is projected on the image planes of the cameras. Pixels which represent the same scene points on different image planes correspond to each other. These correspondences can then be used to determine the three dimensional position of the projected scene point in a defined coordinate system. In more detail, the horizontal displacement, called the disparity, is inverse proportional to the scene pointâs depth. With this information and the cameraâs intrinsic parameters (principal point and focal length), the 3D position can be reconstructed. Fig. 1 shows a typical stereo camera setup. The projections of scene point P are pl and pr. Once the correspondences are found, the disparity is calculated with

Sustainable Transportation Development

Scipedia content — Mon, 25 Jan 2021 11:48:43 +0100

Urban sprawl combined with low density development causes unsustainable development patterns including accessibility and mobility problems, especially for those who do not have the capacity to own a vehicle or access to quality public transport services. Sustainable transportation development is crucial in order to solve transport disadvantage problems in urban settlements. People who are affected by these problems are referred to as âtransportation disadvantagedâ. Transportation disadvantage is a multi-dimensional problem that combines socio-economics, transportation and spatial characteristics or dimensions. However, a substantial number of transportation disadvantage studies so far only focus on the socio-economic and transportation dimensions, while the latter dimension of transportation disadvantage has been neglected. This chapter investigates the spatial dimension of transportation disadvantage by comparing the travel capabilities of residents and their accessibility levels with land use characteristics. The analysis of the study identifies significant land use characteristics with travel inability, and is useful for identifying the transportation disadvantaged population.

Impact and Modeling of Driver Behavior Due to Cooperative Assistance Systems

Scipedia content — Mon, 25 Jan 2021 11:45:01 +0100

Current developments in Car2X communication technology provide the basis for novel driver assistance systems. To assess the impact of such a system on a group of cars approaching a non moving traffic jam, the driver behavior resulting from a system which supports anticipatory driving is modeled and used in a sub-microscopic traffic simulation. By equipping various percentages of a simulated group of cars with the model, the effect of the system on maximum deceleration and fuel consumption can be assessed. Finally the problems resulting from switching between different driver models are discussed.

Cape Verde's infrastructure : a continental perspective

Scipedia content — Mon, 25 Jan 2021 11:43:45 +0100

Cape Verde stands out in West Africa as a country whose economic geography poses major and unique challenges for infrastructure development. Its small population of half a million people is spread across a nine-island archipelago. The islands need complementary infrastructure in terms of roads, water, transport, ports, power, and ICT. Cape Verde already has well-developed infrastructure networks. Road density is relatively high, and most of the national network is paved. Almost all islands have port and airport facilities. Around 70 percent of the population has power and utility water. Indicators for ICT coverage -- penetration, bandwidth, submarine cable, private sector participation -- are relatively good. Nevertheless, prices for all services are exceptionally high. The quality of services is often deficient. At least half of the national road network is in poor condition; power supply is unreliable; and half of the population receives water from standposts. Cape Verde devotes around $147 million per year to infrastructure (almost 15 percent of GDP), among the highest levels of infrastructure spending on the continent. Some $50 million of that is lost each year to operations inefficiencies and underpricing. The country's main challenges are to improve infrastructure management and reduce high costs of services.

Document type: Preprint

Virtual Reality for Nondestructive Evaluation Applications

Scipedia content — Mon, 25 Jan 2021 11:38:17 +0100

Gas transmission pipelines are often inspected and monitored using the magnetic flux leakage method [1]. An inspection vehicle known as a âpigâ is launched into the pipeline and conveyed along the pipe by the pressure of natural gas. The pig contains a magnetizer, an array of sensors and a microprocessor-based data acquisition system for logging data. The data is subsequently retrieved and analyzed offline. The pipeline inspection results in the generation of a vast amount of data â in excess of 4 GB, even in compressed form. It is important that these data are presented in a suitable manner for evaluation by trained operator. Virtual reality (VR) display techniques represent an attractive mechanism for presenting this huge amount of data effectively. The application of VR techniques enables the operator to explore the virtual environment generated by the computer. This technique can serve as an important bridge between human operator and the computer. In this paper, we present some preliminary efforts in achieving this interface.

Competition and Industry Structure for International Rail Transportation

Scipedia content — Mon, 25 Jan 2021 11:34:15 +0100

This paper investigates various options for the organization of the railway industry when network operators require the access to multiple national networks to provide international (freight or passenger) transport services. The EU rail system provides a framework for our analysis. Returns-to-scale and the intensity of competition are key to understanding the impact of vertical integration or separation between infrastructure and operation services within each country in the presence of international transport services. We also consider an option in which a transnational infrastructure manager is in charge of offering a coordinated access to the national networks. In our model, it turns out to be an optimal industry structure.

Measurement of Corrosion Pits in Steel Plates Using a Low-Field Squid Susceptometer

Scipedia content — Mon, 25 Jan 2021 11:24:20 +0100

Nondestructive evaluation methods are largely used for inspection of storage tanks and pipelines in the oil industry. The main goal is to detect and locate points of corrosion which can endanger the structural integrity or the watertightness, possibly causing leakage of oil to the environment, of catastrophic consequences. The occurrence of localized corrosion pits is of special concern, as they weaken the material strength and can initiate cracks at the pit cavity. In low-carbon steel samples, corrosion pits are typically shallow, roughly with the shape of a half-sphere [1].

Biaxial Stress Effects on Barkhausen Signals in a Steel Pipe for the Case of Magnetic Field Noncoaxial with Stress Axes

Scipedia content — Mon, 25 Jan 2021 11:18:08 +0100

Many mechanical stress situations in which NDE might be performed are biaxial in character. Examples are gas and oil pipelines, power plant steam pipes, railroad wheels, and turbine blades.

Supply Chain Event Management System

Scipedia content — Mon, 25 Jan 2021 11:13:47 +0100

The Supply Chain Management (SCM) can be defined as the set of proposals used to efficiently integrate suppliers, manufacturers and warehouses, such that the product is produced and distributed in the right quantity and at the right time, minimizing the total cost and satisfying the required service level (Simchi-Levi et al., 1999). To this aim, enterprises in a Supply Chain (SC) perform collaborative business processes (Soosay et al., 2008). Particularly, collaborative planning processes allow each enterprise to obtain production and/or distribution schedules synchronized with schedules of the other SC members (Derrouiche et al., 2008). In this chapter, a schedule is defined as a set of orders, where each order represents a supply process (production or distribution) that assigns materials to a place, states the required resources, the time period during which each resource is required and its required capacity. The execution of a schedule implies performing the operations defined in the supply process each order represents. As result of the uncertainty inherent in any supply process (Kleindorfer & Saad, 2005) disruptive events arise. The problems they cause during a schedule execution occur on a daily basis, and affect not only the organization where they are produced but also propagate throughout the SC (Lee et al., 1997; Radjou et al., 2002). That is, these disruptive events may affect the schedules and their synchronization. In this chapter a disruptive event is defined as a significant change in the order specifications or planned values of resource availability. These changes could be: rush or delay in the start or end date of the order, changes in the amount specified by the order, change in the expected future availability of a resource, and change into the current level of a resource regards to its planned value. They can be produced by changes that can take place into the enterprise or outside the enterprise. For example, an equipment breakdown, breakage of materials, change of material specification, weather conditions, traffic congestion, etc. The occurrence of disruptive events is a fact well known to the planning task, and therefore planning systems generate schedules including buffers (material, resource capacity and time) to be robust and flexible, thus the schedule can be adapted to conditions occurring during implementation (Van Landeghem & Vanmaele, 2002; Adhitya et al., 2007; Wang &

SESAR and SANDRA: A Co-Operative Approach for Future Aeronautical Communications

Scipedia content — Mon, 25 Jan 2021 10:47:46 +0100

The air transportation sector is currently under significant stress. The sudden decrease in demand for air based transportation after 2001 events, forced most airlines to reorganize and strength their politics by operating severe cuts and by creating strong holding to reverse the negative trend. Air traffic situation returned to pre-September 2001 levels in 2005 and nowadays the demand in aircraft operations is expected to double by 2025. There are many concerns that current air transportation systems will be able to safely cope with this growth (FAA/EUROCONTROL, 2007; SANDRA, 2011). In fact existing systems are unable to completely process flight information in real time, and current processes and procedures do not provide the flexibility needed to meet the growing demand. New security requirements are affecting the ability to efficiently transport people and cargo. Furthermore, air transportation expansion caused community concerns on aircraft noise, air quality, and air space congestion.

Optimization of Neural Network Parameters for Defect Characterization

Scipedia content — Thu, 21 Jan 2021 15:44:58 +0100

Natural gas, which is one of the nationâs cheapest forms of energy, is transported to consumer sites via a vast transmission pipeline network .Safety considerations and a desire to assure uninterrupted energy supply require that the pipelines be inspected periodically. The effective detection of defects in the pipeline is vital to assure the integrity of the transmission systems. A variety of nondestructive evaluation techniques (NDE), such as ultrasonic, eddy current, and magnetic flux leakage (MFL) methods have been employed to detect defects in gas pipelines [1]. Among these methods, the MFL method represents the commonly used technique.

Grouping-Enabled and Privacy-Enhancing Communications Schemes for VANETs

Scipedia content — Thu, 21 Jan 2021 15:44:01 +0100

A vehicular ad hoc network (VANET) is also known as a vehicular sensor network [Zhang, Lu, Lin, Ho & Shen (2008)] by which driving safety is enhanced through inter-vehicle communications or communications with roadside infrastructure. It is an important element of the Intelligent Transportation Systems (ITSs) [Wang et al. (2006)]. In a typical VANET, each vehicle is assumed to have an on-board unit (OBU) and there are road-side units (RSU) installed along the roads. A trusted authority (TA) and maybe some other application servers are installed in the backend. The OBUs and RSUs communicate using the Dedicated Short Range Communications (DSRC) protocol [Oh et al. (1999)] over the wireless channel while the RSUs, TA, and the application servers communicate using a secure fixed network (e.g. the Internet). Based on this infrastructure, vehicles can broadcast safety messages (e.g. road condition, traffic accident information), referred to as âad hoc messagesâ, to other nearby vehicles and RSU such that other vehicles may adjust their travelling routes and RSU may inform the traffic control center to adjust traffic lights for avoiding possible traffic congestion. Like other communication networks, security issues have to be well addressed. For example, the message from an OBU has to be integrity-checked and authenticated. Otherwise, an attacker can replace the safety message from a vehicle or even impersonate a vehicle to transmit a fake safety message. For example, an attacker may impersonate an ambulance to request other vehicles to give way to it or request nearby RSUs to change traffic lights to green. Besides, privacy is another important issue. A driver may not want others to know its driving routes by tracing messages sent by its OBU. Thus an anonymous communications protocol is needed. While being anonymous, a vehicleâs real identity should be revealable by a trusted party when necessary. For example, the driver who sends out fake messages causing an accident should not be able to evade responsibility by using an anonymous identity. In terms of integrity-checking and authentication, digital signature in conventional public key infrastructure (PKI) [Housley et al. (1999)] is a well accepted choice. However, requiring a vehicle to verify the signatures of other vehicles by itself using such schemes as in [Tsang & Smith (2008)] induces two problems as mentioned in [Zhang, Lin, Lu & Ho (2008)]. First, the computation power of an OBU is not adequate to handle all verifications in a short time, especially in places where the traffic density is high. Second, to verify a message from an unknown vehicle involves the transmission of a public key certificate which causes heavy message overhead. Therefore, the general approach is to let the nearby RSU help a vehicle verify the message of another. The volume of signatures to be verified can 9

User Characteristics of Transit Oriented Developments

Scipedia content — Thu, 21 Jan 2021 15:41:35 +0100

Transit oriented developments are high density mixed use developments located within short and easily walkable distance of a major transit centre. These developments are often hypothesised as a means of enticing a mode shift from the private car to sustainable transport modes such as, walking, cycling and public transport. However, it is important to gather evidence to test this hypothesis by determining the travel characteristics of transit oriented developments users. For this purpose, travel surveys were conducted for an urban transit oriented development currently under development. This chapter presents the findings from the preliminary data analysis of the travel surveys. Kelvin Grove Urban Village, a mixed use development located in Brisbane, Australia, has been selected as the case for the transit oriented developments study. Travel data for all groups of transit oriented development users ranging from students to shoppers, and residents to employees were collected. Different survey instruments were used for different transit oriented development users to optimise their response rates, and the performance of these survey instruments are stated herein. The travel characteristics of transit oriented development users are reported in this chapter by explaining mode share, trip length distribution, and time of day of trip. The results of the travel survey reveal that Kelvin Grove Urban Village users use more sustainable modes of transport as compared to other Brisbane residents.

Railway electrification 1920-40

Scipedia content — Thu, 21 Jan 2021 15:17:01 +0100

By 1920, electric traction was well established on rapid-transit railways, tunnel lines, mountain railways and sections of main line railway in difficult terrain. These electric railways opened during the period when railway transport enjoyed a near monopoly on land for passenger traffic and long-distance goods movements, though after 1920 competition came from road transport when the state encouraged demobilised soldiers to set up motor bus and road haulage companies to create the motor-vehicle expertise which would be needed in a future war. Air transport using airships or aeroplanes was recognised as a potential threat.

Traffic Congestion Effects on Supply Chains: Accounting for Behavioral Elements in Planning and Economic Impact Models

Scipedia content — Thu, 21 Jan 2021 15:16:22 +0100

As traffic volumes and congestion grows on highways and urban roadways, freight and delivery service operators become increasingly challenged to maintain dependable and reliable schedules. This affects supply chains and truck-dependent businesses both of which are of increasing importance for both public policy and private sector operators. From the public perspective, there is a need to make investment, financing and policy decisions based on an understanding of public infrastructure needs, costs and broader economic stakes involved. From the perspective of shippers and carriers, there are the day-to-day cost implications of delay and reliability as it affects supply chain management, and well as a longer-range need to assess opportunities, risks and returns associated with location, production and distribution decisions. Both perspectives need to be recognized when considering the full range of impacts that traffic congestion can have on the economy. A barrier to considering these two perspectives together is the gap that exists between theoretical simulation modeling and real world observations of business responses to congestion. A review of research literature reveals a number of theoretical models which posit that the generalized growth of traffic congestion adds to total transport costs for delivered products, causing firms to shift location and shipment size configurations to reoptimize net revenues. However, industry publications and business interviews reveal a wider variety of behavioral responses that depend on the type and timing of congestion delays (bottlenecks at specific ports, intermodal facilities, highways or urban road networks) and their frequency, leading to a range of operational responses as a hedge against both expected and unexpected delay. The nature of the affected parties, and the form of operational responses, can vary widely by industry. The impacts can span different supply chain configurations â including not only the movement of material and parts to producers and then to distributors, but also local distribution and delivery of finished goods to retail markets, and even local delivery of parts and repair services to businesses and households. For service-oriented economies, more sophisticated changes in operations â especially those that depend on efficiency of over-the-road operations â can be limited or entirely foreclosed by congestion. In a broad sense, all of these forms of movement have supply chain elements. And they share a common factor, which is that they are very much affected by the degree of of unpredictability and variation in delays associated with growing congestion.

Directed Cultural Probes: Detecting Barriers in the Usage of Public Transportation

Scipedia content — Thu, 21 Jan 2021 15:10:23 +0100

Part 2: Long and Short Papers; International audience; In this paper we describe the application of a variation of cultural probing for identifying barriers in the use of public transportation for target groups with visual, cognitive or language-related handicaps. To be able to better focus on the targeted aspect - the barriers - we applied modifications to the traditional cultural probing approach: Users were encouraged to generate data related to the targeted aspect. We found that this approach can produce focused results that can be analysed fast and can help to overcome obstacles related to limitations in verbal skills or expressiveness of the user.

Document type: Part of book or chapter of book

The LDACS1 Link Layer Design

Scipedia content — Thu, 21 Jan 2021 15:09:48 +0100

Air transportation is an important factor for the economic growth of the European Union, however, the current system is already approaching its capacity limits and needs to be reformed to meet the demands of further sustainable development (Commission of the European Communities, 2001). These limitations stem mainly from the current European air traffic control system. Air traffic control within Europe is fragmented due to political frontiers into regions with different legal, operational, and regulative contexts. This fragmentation decreases the overall capacity of the European air traffic control system and, as the system is currently approaching its capacity limits, causes significant congestion of the airspace. According to the European Commission airspace congestion and the delays caused by it cost airlines between â¬1.3 and â¬1.9 billion a year (European Commission, 2011). For this reason, the European Commission agreed to adopt a set of measures on air traffic management to ensure the further growth and sustainable development of European air transportation. The key enabler of this transformation is the establishment of a Single European Sky1 (SES). The objective of the SES is to put an end to the fragmentation of the European airspace and to create an efficient and safe airspace without frontiers. This will be accomplished by merging national airspace regions into a single European Flight Information Region (FIR) within which air traffic services will be provided according to the same rules and procedures. In addition to the fragmentation of the airspace the second limiting factor for the growth of European air transportation lies within the legacy Air Traffic Control (ATC) concept. In the current ATC system, which has been developed during the first half of the twentieth century, aircraft fly on fixed airways and change course only over navigation waypoints (e.g. radio beacons). This causes non-optimal paths as aircraft cannot fly directly to their destination and results in a considerable waste of fuel and time2. In addition, it concentrates aircraft onto airways requiring ATC controllers to ascertain their safe separation. The tactical control of aircraft by ATC controllers generates a high demand of voice communication which is proportional to the amount of air traffic. As voice communication

WHI Formula as a New Criterion in Automatic Pipeline GMAW Process

Scipedia content — Thu, 21 Jan 2021 15:06:37 +0100

Pipeline welding is one of the most significant applications of GMAW process. Automatic welding for pipelines has been developed from early 1970âs. In these systems the welding robot moves around the two pipe's seam and welds the pipes by arc welding machine. Depending on the pipe thickness, weld process is repeated in several passes while the seam is filled of weld mass. The automatic pipeline welding systems has been recently paid more attention [1, 2]. In order to achieve sufficient performance in the process, the input parameters must be chosen correctly [3]. Welding parameter designing is a complicated step in the GMAW process, because of the large number of parameters and complexity of dynamic behavior. This complexity is particularly intensified in automatic pipeline systems, because of the complex seam geometry, wide range of the angle variations and strict quality requirements [1]. The most important input parameters in the automatic pipeline GMAW process are: welding current, arc voltage, travel speed, wire feeding speed, Contact Tube to Workpiece Distance (CTWD), welding position (angle), gas type, pipe type/thickness and seam geometry [4, 5]. The output parameters of the process are usually defined as either mechanical properties or weld bead geometry [6]. Weld bead geometry method considers the relationships between the input parameters and weld bead dimensions (penetration, width, reinforcement height, and width to penetration ratio and dilution [3, 7, 8]. Appropriate melting of the seam walls is certainly one of the most important conditions to achieve a proper dimension in fusion zone. A fusion zone with a sufficient width is necessary to prevent from some defects like lack of Fusion (LOF) [9, 10]. Having a direct contact between the arc and seam walls and receiving enough energy to the walls led to suitable wall melting and appropriate fusion zone [11, 12]. Some criteria such as heat input are related to the total energy which is given to the weld region without considering the amount of energy required to melt the wire. Principal parameters to calculate the heat input value are: welding current, arc voltage, travel speed and welding efficiency [11, 13]. During the welding process, part of the arc energy is spent to melt the wire [12]. Seam geometry also plays an important role in the amount of arc energy that directly reaches the walls. However a more general formula is not yet introduced.

Electric Vehicles in an Urban Context: Environmental Benefits and Techno-Economic Barriers

Scipedia content — Thu, 21 Jan 2021 15:04:46 +0100

Mobility of persons and goods is a crucial component of the competitiveness of the economy; mobility is also an essential citizen right. Effective transportation systems are important for social prosperity, having significant impacts on economic growth, social development and the environment. The goal of any sustainable transport policy is to ensure that our transport systems meet society's economic, social and environmental needs. In 2006 the transport sector consumed 31% of the total final energy consumption (of which 82% is due to road transport) and was responsible for 25% of CO2 emissions (EU-27). In 2007 road transport constituted about 83% of passenger total transport demand. Road transport accounts for 71% of transport related CO2 emissions and passenger cars constitute 63% of these road transport related CO2 emissions. Currently, road transport is also totally dependent ("90%) of fuel oil making it very sensitive to foreseeable shortage of crude oil, besides largely contributing to air pollutants such as NOx, PM10 and volatile organic compounds. It is estimated that more than 80% of the developed world population lives in an urban environment and therefore it is in this environment where a larger concentration of vehicles are found. As example there were about 230 million passenger vehicles in the EU-27 in 2007 and the new vehicle sales were nearly 16 million vehicles in that year. Consequently the urban population is very much at risk by directly suffering the impact of conventional vehicles because their closeness to the pollutant source. Air pollution is one of the important external costs of transport as it impacts on the health of the population (it is estimated to be 0.75% of the EU GDP). On the other hand, the large concentration of vehicles causes traffic congestions in metropolitan urban areas that can be considered a threat to economic

Quality of Service Management and Interoperability

Scipedia content — Thu, 21 Jan 2021 15:02:27 +0100

Within this chapter quality of service management strategies are assessed with respect to their applicability and efficiency in the Air Traffic Management (ATM) context. In particular addressing the service demands of ATM communication, such as strict latency and loss limitations is considered herein. This also covers techniques for the selection of links for data transmission and the interaction between technology independent and technology dependent components in the networking architecture by means of standardized communication protocols such as IEEE 802.21 and ETSI BSM extensions.

New Work in Acoustic Leak Location in Underground Pipelines

Scipedia content — Thu, 21 Jan 2021 14:53:06 +0100

During the last ten years, the nation has become increasingly aware of the potential for environmental damage from leaks in underground and aboveground storage tanks, and related pipelines. Federal and state regulations have been developed that mandate inspections, require regular testing and set out design standards of construction for underground storage systems. More specifically, existing federal regulations (40 CFR Parts 280 and 281, September 1988) require that underground tanks and pipelines containing petroleum products and other hazardous substances be tested for leaks on a regular basis and that once a leak has been detected, it be corrected. While this requirement appears to be relatively simple, it, in fact, presents substantial difficulty in implementation. The difficulties are of two types.

Integrity of Pipelines Transporting Hydrocarbons

Scipedia content — Thu, 21 Jan 2021 14:44:28 +0100

Free Parking or Free Markets

Scipedia content — Thu, 21 Jan 2021 14:38:33 +0100

Free Parking or Free Markets DONALD SHOUP It is no doubt ironic that the motorcar, superstar of the capitalist system, expects to live rent-free. W OLFGANG Z UCKERMAN C ITIES SHOULD CHARGE THE RIGHT PRICES FOR CURB PARKING because the wrong prices produce such bad results. Where curb parking is underpriced and overcrowded, a surprising share of cars on congested streets can be searching for a place to park. Sixteen studies conducted between 1927 and 2001 found that, on average, 30 percent of the cars in congested downtown traffic were cruising for parking. More recently, when researchers interviewed drivers stopped at traffic signals in New York City in 2006 and 2007, they found that 28 percent of the drivers on a street in Manhattan and 45 percent on a street in Brooklyn were cruising for curb parking. In another study in 2008, the average time it took to find a curb space in a 15 block area of the Upper West Side of Manhattan was 3.1 minutes and the average cruising distance was 0.37 miles. For each individual driver, 3.1 minutes is not a long time, and 0.37 miles is not a long distance, but because there are so many drivers, the cumulative consequences are staggering. In a year, cruising for underpriced parking on these 15 blocks alone creates about 366,000 excess vehicle miles of travel (equal to 14 trips around the earth) and 325 tons of CO 2 . Donald Shoup is Professor of Urban Planning in the Luskin School of Public A ffairs at the University of California, L os Angeles (shoup@ucla.edu). A C C E S S

Human-centered challenges and contributions for the implementation of automated driving

Scipedia content — Thu, 21 Jan 2021 14:30:35 +0100

Automated driving is expected to increase safety and efficiency of road transport. With regard to the implementation of automated driving, we observed that those aspects which need to be further developed especially relate to human capabilities. Based on this observation and the understanding that automation will most likely be applied in terms of partially automated driving, we distinguished 2 major challenges for the implementation of partially automated driving: (1) Defining appropriate levels of automation, and; (2) Developing appropriate transitions between manual control and automation. The Assisted Driver Model has provided a framework for the first challenge, because this model recommends levels of automation dependent on traffic situations. To conclude, this research also provided brief directions on the second challenge, i.e. solutions how to accommodate drivers with partially automation

New Robust Obstacle Detection System Using Color Stereo Vision

Scipedia content — Thu, 21 Jan 2021 14:23:34 +0100

Intelligent transportation systems (ITS) are divided into intelligent infrastructure systems and intelligent vehicle systems. Intelligent vehicle systems are typically classified in three categories, namely 1) Collision Avoidance Systems; 2) Driver Assistance Systems and 3) Collision Notification Systems. Obstacle detection is one of crucial tasks for Collision Avoidance Systems and Driver Assistance Systems. Obstacle detection systems use vehiclemounted sensors to detect obstuctions, such as other vehicles, bicyclists, pedestrians, road debris, or animals, in a vehicleâs path and alert the driver. Obstacle detection systems are proposed to help drivers see farther and therefore have more time to react to road hazards. These systems also help drivers to get a large visibility area when the visibility conditions is reduced such as night, fog, snow, rain, ... Obstacle detection systems process data acquired from one or several sensors: radar Kruse et al. (2004), lidar Gao & Coifman (2006), monocular vision Lombardi & Zavidovique (2004), stereo vision Franke (2000) Bensrhair et al. (2002) Cabani et al. (2006b) Kogler et al. (2006) Woodfill et al. (2007), vision fused with active sensors Gern et al. (2000) Steux et al. (2002) Mobus & Kolbe (2004)Zhu et al. (2006) Alessandretti et al. (2007)Cheng et al. (2007). It is clear now that most obstacle detection systems cannot work without vision. Typically, vision-based systems consist of cameras that provide gray level images. When visibility conditions are reduced (night, fog, twilight, tunnel, snow, rain), vision systems are almost blind. Obstacle detection systems are less robust and reliable. To deal with the problem of reduced visibility conditions, infrared or color cameras can be used. Thermal imaging cameras are initially used by militaries. Over the last few years, these systems became accessible to the commercial market, and can be found in select 2006 BMW cars. For example, vehicle headlight systems provide between 75 to 140 meters of moderate illumination; at 90 K meters per hour this means less than 4 seconds to react to hazards. When with PathFindIR PathFindIR (n.d.) (a commercial system), a driver can have more than 15 seconds. Other systems still in the research stage assist drivers to detect pedestrians Xu & Fujimura (2002) Broggi et al. (2004) Bertozzi et al. (2007). Color is appropriate to various visibility conditions and various environments. In Betke et al. (2000) and Betke & Nguyen (1998), Betke et al. have demonstrated that the tracking of

Integrating Business Processes to Improve Travel Time Reliability

Scipedia content — Thu, 21 Jan 2021 14:20:38 +0100

Improving travel time reliability is an emerging business activity for transportation agencies in the United States. To improve the reliability of travel times on their roadway networks, transportation agencies must advance on a number of fronts. These include collecting and analyzing data; integrating travel time reliability considerations into planning, programming, and project delivery; adopting innovative operational strategies and technologies; and modifying their institutional structures and business practices surrounding traffic operations. This report addresses various ways that transportation agencies can reengineer their day-to-day business practices to improve traffic operations, address nonrecurring traffic congestion, and improve the reliability of travel times delivered to roadway system users. The report is based on a series of case studies, mainly from the United States, that describe successful business processes.

The Inspection of Chemical Plant Pipework Using Lamb Waves: Defect Sensitivity and Field Experience

Scipedia content — Thu, 21 Jan 2021 14:17:55 +0100

Corrosion and pitting defects in pipework are major problems in the oil, chemical and other industries. These defects can occur at the outer or inner surface of the pipe and can lead to a serious loss of pipe wall thickness. As a high proportion of industrial pipelines are insulated, this means that even external corrosion cannot readily be detected without the removal of the insulation, which in most cases is prohibitively expensive.

Modeling and Simulation of Vehicular Networks: towards Realistic and Efficient Models

Scipedia content — Thu, 21 Jan 2021 13:43:48 +0100

Vehicular Ad Hoc Networks (VANETs) have been envisioned with three types of applications in mind: safety, traffic management, and commercial applications. By using wireless interfaces to form an ad hoc network, vehicles will be able to inform other vehicles about traffic accidents, hazardous road conditions and traffic congestion. Commercial applications (e.g., data exchange, audio/video communication) are envisioned to provide incentive for faster adoption of the technology. To date, the majority of VANET research efforts have relied heavily on simulations, due to prohibitive costs of employing real world testbeds. Current VANET simulators have gone a long way from the early VANET simulation environments, which often assumed unrealistic models such as random waypoint mobility, circular transmission range, or interference-free environment Kotz et al. (2004). However, significant efforts still remain in order to enhance the realism of VANET simulators, at the same time providing a computationally inexpensive and efficient platform for performance evaluation of VANETs.

Feasibility of Using In-Vehicle Video Data to Explore How to Modify Driver Behavior That Causes Nonrecurring Congestion

Scipedia content — Thu, 21 Jan 2021 13:37:43 +0100

This research reportâa product of the Reliability focus area of the second Strategic Highway Research Program (SHRP 2)âpresents findings on the feasibility of using existing in-vehicle data sets, collected in naturalistic driving settings, to make inferences about the relationship between observed driver behavior and nonrecurring congestion. General guidance is provided on the protocols and procedures for conducting video data reduction analysis. In addition, the report includes technical guidance on the features, technologies, and complementary data sets that researchers should consider when designing future instrumented in-vehicle data collection studies. Finally, a new modeling approach is advanced for travel time reliability performance measurement across a variety of traffic congestion conditions.

Uncertainty Analysis of the Life-Cycle Greenhouse Gas Emissions and Energy Renewability of Biofuels

Scipedia content — Thu, 21 Jan 2021 13:34:29 +0100

Biofuels can contribute substantially to energy security and socio-economic development. However, significant disagreement and controversies exist regarding the actual energy and greenhouse gas (GHG) savings of biofuels displacing fossil fuels. A large number of publications that analyze the life-cycle of biofuel systems present varying and sometimes contradictory conclusions, even for the same biofuel type (Farrell et al., 2006; Malca and Freire, 2004, 2006, 2011; Gnansounou et al., 2009; van der Voet et al., 2010; Borjesson and Tufvesson, 2011). Several aspects have been found to affect the calculation of energy and GHG savings, namely land use change issues and modeling assumptions (Gnansounou et al., 2009; Malca and Freire, 2011). Growing concerns in recent years that the production of biofuels might not respect minimum sustainability requirements led to the publication of Directive 2009/28/EC in the European Union (EPC 2009) and the National Renewable Fuel Standard Program in the USA (EPA 2010), imposing for example the attainment of minimum GHG savings compared to fossil fuels displaced. The calculation of life cycle GHG emission savings is subject to significant uncertainty, but current biofuel life-cycle studies do not usually consider uncertainty. Most often, life-cycle assessment (LCA) practitioners build deterministic models to approximate real systems and thus fail to capture the uncertainty inherent in LCA (Lloyd and Ries, 2007). This type of approach results in outcomes that may be erroneously interpreted, or worse, may promote decisions in the wrong direction (Lloyd and Ries, 2007; Plevin, 2010). It is, therefore, important for sound decision support that uncertainty is taken into account in the life-cycle modeling of biofuels. Under this context, this chapter has two main goals: i) to present a robust framework to incorporate uncertainty in the life-cycle modeling of biofuel systems; and ii) to describe the application of this framework to vegetable oil fuel in Europe. In addition, results are compared with conventional (fossil) fuels to evaluate potential savings achieved through displacement. Following this approach, both the overall uncertainty and the relative importance of the different types of uncertainty can be assessed. Moreover, the relevance of addressing uncertainty issues in biofuels life-cycle studies instead of using average deterministic approaches can be evaluated, namely through identification of important aspects that deserve further study to reduce the overall uncertainty of the system.

Towards Automotive Embedded Systems with Self-X Properties

Scipedia content — Thu, 21 Jan 2021 13:29:46 +0100

Since the first pieces of software have been introduced into automobiles in 1976, the complexity of automotive software systems is growing rapidly. Today automotive software is widely installed for diverse applications ranging from the infotainment domain (e.g. entertainment, navigation, etc.) with typically no real-time requirements to safety-critical control software (e.g. engine control, safety functionalities, etc.) with hard real-time requirements. In addition, many comfort functionalities of automobiles are realized by software nowadays (e.g. the control of the air condition system, electronic window regulator, etc.). Up to 90% of todayâs innovations in the automotive industry are realized by hardand software (Pretschner et al., 2007). This results in up to 2,500 âatomicâ functions realized in software on up to 67 electronic control units (ECUs) in modern high-end cars (Furst, 2010). For the future development of automobile electronics, there are two major trends: A growing number of functionalities and through this a growing importance of software in the car (Hardung et al., 2004). Future generations of cars will be equipped with many new, complex features (Czarnecki & Eisenecker, 2000). For example, functionalities to support active driving safety (e.g. driver assistance systems), features which enable new innovative driving concepts (e.g. engine control for hybrid vehicles), or new functionalities in the comfort domain (e.g. new infotainment features). Most of these functionalities will be realized in software, which increases the amount and importance of software within the automotive domain necessarily. But these new features will also increase the complexity of future vehicular system architectures. For instance, driver assistance systems increase the complexity because they interact with several in-vehicle domains, e.g. the power-train and infotainment domain. In future, the trend of establishing more and more interactions between software components will continue, e.g. through x-by-wire features, where mechanical transmission is replaced by electrical signals. This results in a growing interdependency of separated software domains and in an increased need for interconnection. Another important aspect is the continuously growing number of functional variants caused by customer-specific equipment options or country-specific regulations. At the same time, the demand on the software quality within the automotive domain is very high at all times. These requirements must be satisfied in the future, despite the increasing complexity of automotive software architectures. Even today it is a great challenge to manage these systems from the outside.

Towards an autonomous and intelligent Airline Operations Control

Scipedia content — Thu, 21 Jan 2021 13:29:09 +0100

Studies have estimated that irregular operations (flights affected by a disruption) can cost between 2% and 3% of the airline annual revenue and that a better recovery process could result in cost reductions of at least 20%. Even for small airlines this can represent millions of Euros. In this paper we propose a multi-agent system (MAS) whose members represent the roles, functionalities and competences existing in a typical Airline Operations Control Centre (AOCC), the airline entity responsible for managing the impact of irregular events on planned operations. This multiagent based system produces intelligent solutions in the sense that its outcomes are the result of an autonomous reaction and adaption to changes in the environment, solving partial problems simultaneously. We tested our MAS using real data from TAP Portuguese airline company and experimentally compared our system with solutions found by the human operators on TAP Portugal AOCC. A comparison was also made with a more traditional sequential approach that is the typical method followed by AOCCs when solving disruptions. Results from those comparisons show that it is possible to reduce costs and have a better integrated solution with the proposed system.

SOA-Based Aeronautical Service Integration

Scipedia content — Thu, 21 Jan 2021 13:22:52 +0100

Over the past two decades, the air transport industry has experienced continuous growth. The demand for passenger air traffic is forecast to double the current level by about 2025 (European Organisation for the Safety of Air Navigation [EUROCONTROL], 2006). Smallto-medium sized low cost airlines in Europe such as EasyJet and Ryanair have observed a considerable percentage of passenger increase between 2008 and 2009 due to the growth in the number of regional airports and more choices offered on international destinations (EasyJet & Ryanair, 2009). To accommodate such growth and changes in new flight patterns and strategies, it is of paramount importance to ensure air transport communication systems around the globe be integrated to enable efficient air-to-ground and ground-to-ground communications for global air traffic management and coordination. Traditional approaches for aeronautical system integration in the past impose a high level of system dependencies; a fixed connection is required to be set up every time a new application is added. Therefore, aviation companies are facing continuous investment increase every time a new connection is established. This situation discourages enterprises from fulfilling grater business values by adding interior constraints; it restricts the number of applications and services that can be integrated into the existing IT infrastructure. In safety-critical systems in the aeronautical context, overloaded complex system structure will increase the chances of operational failures and jeopardise passenger safety. Therefore, it is important to devise a suitable architecture which minimises system dependencies and allows new applications to be integrated easily with the lowest IT maintenance budget. A layer-extensible blueprint in a Service-Oriented Architecture (SOA) is considered as a solution in this case for the integration of future aeronautical communication systems. The proposed framework should allow consistent data capturing and sharing among all end users who are involved in the global aircraft operations in the 2020 timeframe and beyond. In recent years, the SESAR SWIM (Single European Sky Air Traffic Management Research System Wide Information Management) concept has reflected the emerging needs and willingness of Air Traffic Management (ATM) organisations in transforming proprietary ATM systems into a standardised and interoperable information pool in the pan-European aeronautical network. As the challenge still exists where the ATM stakeholders today do not want to deal with the complexity of the lower communication layers, SOA is considered

Time–Distance Helioseismology Data-Analysis Pipeline for Helioseismic and Magnetic Imager Onboard Solar Dynamics Observatory (SDO/HMI) and Its Initial Results

Scipedia content — Thu, 21 Jan 2021 13:20:04 +0100

The Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO/HMI) provides continuous full-disk observations of solar oscillations. We develop a data-analysis pipeline based on the time-distance helioseismology method to measure acoustic travel times using HMI Doppler-shift observations, and infer solar interior properties by inverting these measurements. The pipeline is used for routine production of near-real-time full-disk maps of subsurface wave-speed perturbations and horizontal flow velocities for depths ranging from 0 to 20 Mm, every eight hours. In addition, Carrington synoptic maps for the subsurface properties are made from these full-disk maps. The pipeline can also be used for selected target areas and time periods. We explain details of the pipeline organization and procedures, including processing of the HMI Doppler observations, measurements of the travel times, inversions, and constructions of the full-disk and synoptic maps. Some initial results from the pipeline, including full-disk flow maps, sunspot subsurface flow fields, and the interior rotation and meridional flow speeds, are presented.

Green Transport Infrastructure

Scipedia content — Thu, 21 Jan 2021 13:16:57 +0100

In an age when escalating fuel prices, global warming and world resource depletion are of great concern, sustainable transport practices promise to define a new way of mobility into the future. With its comparatively minimal negative environmental impacts, non reliance on fuels and positive health effects, the simple bicycle offers significant benefits to humankind. These benefits are evident worldwide where bicycles are successfully endorsed through improved infrastructure, supporting policies, public education and management. In Australia, the national, state and local governments are introducing measures to improve and support green transport. This is necessary as current bicycle infrastructure is not always sufficient and the longstanding conflict with motorized transport still exists. The aim for the future is to implement sustainable hard and soft bicycle infrastructure globally; the challenges of such a task can be illustrated by the city of Brisbane, Australia.

3D Finite Element Methods for Modeling MFL Inspection of Pipelines

Scipedia content — Thu, 21 Jan 2021 13:12:43 +0100

It is estimated that there are about one million kilometers of gas and liquid transmission pipelines operating across the globe today. Pipelines, owing to their strategic role of transporting gas and liquid fuels, are of immense capital value. Potential degradation and failure of pipelines is a sensitive issue both with the public and legislative bodies, since the consequences of failure could include injuries and death. In addition, pipeline failures have severe financial consequences. More than half the pipelines in use today are 30 or more years old and invariably have experienced some deterioration. Preventive maintenance using nondestructive evaluation (NDE) techniques plays an important role in ensuring safe pipeline operation [1].

The Role of Satellite Systems in Future Aeronautical Communications

Scipedia content — Thu, 21 Jan 2021 13:09:57 +0100

Recent evolutions in the context of aeronautical communications have changed the landscape and the role of the different systems that allow aircrafts to maintain a link with the ground while in flight. The increase in capacity needed to support the growth of worldwide air traffic and the need for increased communication safety are driving a transition from voice-centric procedures aided by slow data link connections to data-centric control applications executed on higher capacity communication systems. These future data links have to fulfil very stringent performance requirements. Indeed, the nature of the information they carry which is bound to become the first mean of air traffic control make their availability critical to the safety of air transportation in the future. Satellite communication systems have many differentiating arguments when compared to terrestrial solutions. Indeed, while the deployment costs of terrestrial systems can be sustainable in high-density areas, their use in low-density remote areas is much less interesting. In high-density areas, satellite could also be useful either as a primary mean of communication or as a secondary one in order to improve the overall communication systemâs availability. A satellite system, by nature, is able to cover large regions of the earth and can thus provide a cost effective solution to the coverage of both high and low density areas such as oceanic regions where reliable terrestrial coverage is nonexistent. In this paper, the interest of a satellite solution to be used as a data link for future aeronautical communications is studied. After presenting an overview of the existing satellite systems for aeronautical communication in operation today, the discussion focuses on the interest and strength of the forthcoming satellite link under definition in the frame of the ESA Iris Programme and its integration in the communication concept defined by the SANDRA EC FP7 project.

Dei treni e dei riti. Politiche ferroviarie e memoria estetico-rituale nella Tokyo contemporanea

Scipedia content — Thu, 21 Jan 2021 13:05:36 +0100

Modeling and Simulation for Steady State and Transient Pipe Flow of Condensate Gas

Scipedia content — Thu, 21 Jan 2021 13:02:48 +0100

Condensate gas is mainly demonstrated by methane. However, it also contains a lot of heavier contents like C5 or C5+ and some non-hydrocarbon mixture as well (Mokhatab et al, 2006). After recovering from gas wells, condensate gas needs liquid separation, gas purification and condensate stabilization treatment in the processing plant to meet the quality requirements. Processing plants far away from the gas well with long distances of two-phase flow in one condensate gas pipeline will take less investment than adjacent process plant with two single phase pipelines which are dry gas pipeline and liquid phase pipeline (Li, 2008). If the operation temperature somewhere in the condensate gas pipeline is lower than the gas dew point, liquid condensation would occur, subjecting the pipeline to two phase flow (Potocnik, 2010). While gas and its condensate flow simultaneously, mass transfer takes place continuously due to the change in pressure and temperature conditions. This leads to compositional changes and associated fluid property changes and also makes the hydraulic and thermal calculations of condensate gas more complex than normal gas. The condensate gas pipeline model which is established and solved based on the principle of fluid mechanics can simulate hydraulic and thermal parameters under various operation conditions. By means of technical support, this model is of great importance in the pipeline design and safety operation aspects (Mokhatab, 2009).

Rapid filling of pipelines with the SPH particle method

Scipedia content — Tue, 19 Jan 2021 16:33:35 +0100

The paper reports the development and application of a SPH (smoothed particle hydrodynamics) based simulation of rapid filling of pipelines, for which the rigid-column model is commonly used. In this paper the water-hammer equations with a moving boundary are used to model the pipe filling process, and a mesh-less Lagrangian particle approach is employed to solve the governing equations. To assign boundary conditions with time-dependent (upstream) and constant (downstream) pressure, the SPH pressure boundary concept proposed recently in literature is used and extended. Except for imposing boundary conditions, this concept also ensures completeness of the kernels associated with particles close to the boundaries. As a consequence, the boundary deficiency problem encountered in conventional SPH is remedied. The employed particle method with the SPH pressure boundary concept aims to predict the transients occurring during rapid pipe filling. It is validated against laboratory tests, rigid-column solutions and numerical results from literature. Results obtained with the present approach show better agreement with the test data than those from rigid-column theory and the elastic model solved by the box scheme. It is concluded that SPH is a promising tool for the simulation of rapid filling of pipelines with undulating elevation profiles. Keywords: Rapid filling of pipelines; Undulating elevation profile; SPH

Methodology, evaluation, simulation and assessment for the analysis of the deployment of DSB and EEIC systems of the FREILOT project Contribution of LET

Scipedia content — Mon, 26 Oct 2020 15:37:05 +0100

This report contains the main contribution of CNRS-LET to the FREILOT project. It is organized in 4 main parts: the first presents the methodological contributions to the evaluation of ICT systems, the second the methodological contribution to the delpoyment assessment and analysis. The other two concern mainly the evaluation results produced by LET and the Cost Benefit Analyses and results made also by LET.

Document type: Report

Hydrogen pipeline compressors annual progress report

Scipedia content — Mon, 26 Oct 2020 11:25:05 +0100

The objectives are: (1) develop advanced materials and coatings for hydrogen pipeline compressors; (2) achieve greater reliability, greater efficiency, and lower capital in vestment and maintenance costs in hydrogen pipeline compressors; and (3) research existing and novel hydrogen compression technologies that can improve reliability, eliminate contamination, and reduce cost. Compressors are critical components used in the production and delivery of hydrogen. Current reciprocating compressors used for pipeline delivery of hydrogen are costly, are subject to excessive wear, have poor reliability, and often require the use of lubricants that can contaminate the hydrogen (used in fuel cells). Duplicate compressors may be required to assure availability. The primary objective of this project is to identify, and develop as required, advanced materials and coatings that can achieve the friction, wear, and reliability requirements for dynamically loaded components (seal and bearings) in high-temperature, high-pressure hydrogen environments prototypical of pipeline and forecourt compressor systems. The DOE Strategic Directions for Hydrogen Delivery Workshop identified critical needs in the development of advanced hydrogen compressors - notably, the need to minimize moving parts and to address wear through new designs (centrifugal, linear, guided rotor, and electrochemical) and improved compressor materials. The DOE is supporting several compressor design studiesmoreÂ Â» on hydrogen pipeline compression specifically addressing oil-free designs that demonstrate compression in the 0-500 psig to 800-1200 psig range with significant improvements in efficiency, contamination, and reliability/durability. One of the designs by Mohawk Innovative Technologies Inc. (MiTi{reg_sign}) involves using oil-free foil bearings and seals in a centrifual compressor, and MiTi{reg_sign} identified the development of bearings, seals, and oil-free tribological coatings as crucial to the successful development of an advanced compressor. MiTi{reg_sign} and ANL have developed potential coatings for these rigorous applications; however, the performance of these coatings (as well as the nickel-alloy substrates) in high-temperature, high-speed hydrogen environments is unknown at this point.Â«Â le

Document type: Report

The effects of simplifying traffic zone and street network systems on the accuracy of traffic assignments in small urban areas in indiana

Scipedia content — Mon, 26 Oct 2020 10:30:33 +0100

As a part of a detailed study of synthetic travel demand modelling techniques that can be applied to small urban areas (population 50,000 to 250,000), this study concentrated solely on the traffic assignment phase of the modelling process. The study considered the effects of the following factors on the accuracy of traffic assignment: number of traffic zones, use of census tracts as traffic zones, complexity of the network configuration and method of traffic assignment. Transportation network and travel data from two small Indiana urban areas, Lafayette and Anderson, were used. The results indicated that traffic zones, based upon census tract boundaries, and street networks with less detail, can be used without significant reduction in assignment accuracy. For the small urban areas considered in the study 90 internal zones can provide acceptable accuracy in traffic assignment.

Document type: Report

Barranquilla's port: challenges and recomendations

Scipedia content — Mon, 26 Oct 2020 10:00:01 +0100

The port of Barranquilla is located on the western margin of the Magdalena River, 22 km before the river mouth at the Caribbean Sea. Nowadays, it is ranked fourth among the biggest ports of the country in terms of cargo volume. Nevertheless, it has problems for navigation throughout his access channel due to the accumulation of the sediments dragged by the discharge of the river, which has caused the port to loss competitiveness in comparison with other deepwater ports of the region like Santa Marta and Cartagena. This problem demonstrates the lack of a policy of maintenance of the access channel that guarantees the entry and exit of large vessels at any time. Even so, the port has a promising future, based on the reactivation of the navigation throughout the Magdalena River. Therefore, the presence of the port of Barranquilla will be key in order to connect inland factories with the Caribbean Sea through the Magdalena River. RESUMEN: El puerto de Barranquilla se encuentra ubicado sobre la margen occidental del rÃo Magdalena, a 22 km de la desembocadura del rÃo en el mar Caribe. En la actualidad, es el cuarto puerto mÃ¡s importante del paÃs por volumen de carga transportada. Sin embargo, presenta problemas para la navegaciÃ³n a lo largo de su canal de acceso por la acumulaciÃ³n de los sedimentos arrastrados por la corriente del rÃo, lo que ha hecho que pierda competitividad frente a otros puertos de aguas profundas como Cartagena y Santa Marta. Este problema evidencia la falta de una polÃtica de mantenimiento del canal que garantice la entrada y salida de grandes embarcaciones al puerto en cualquier momento. AÃºn asÃ, el puerto cuenta con un futuro prometedor, ya que en los prÃ³ximos aÃ±os se planea realizar importantes inversiones para reactivar la navegaciÃ³n por el rÃo Magdalena y el puerto de Barranquilla serÃ¡ la pieza clave para conectar el interior del paÃs con el mar Caribe por medio del rÃo Magdalena.

Document type: Report

Blending study for srr salt disposition integration tank 50h scale modeling and computer modeling for blending pump design phase 2

Scipedia content — Mon, 26 Oct 2020 09:53:52 +0100

The Salt Disposition Integration (SDI) portfolio of projects provides the infrastructure within existing Liquid Waste facilities to support the startup and long term operation of the Salt Waste Processing Facility (SWPF). Within SDI, the Blend and Feed Project will equip existing waste tanks in the Tank Farms to serve as Blend Tanks where 300,000-800,000 gallons of salt solution will be blended in 1.3 million gallon tanks and qualified for use as feedstock for SWPF. Blending requires the miscible salt solutions from potentially multiple source tanks per batch to be well mixed without disturbing settled sludge solids that may be present in a Blend Tank. Disturbing solids may be problematic both from a feed quality perspective as well as from a process safety perspective where hydrogen release from the sludge is a potential flammability concern. To develop the necessary technical basis for the design and operation of blending equipment, Savannah River National Laboratory (SRNL) completed scaled blending and transfer pump tests and computational fluid dynamics (CFD) modeling. A 94 inch diameter pilot-scale blending tank, including tank internals such as the blending pump, transfer pump, removable cooling coils, and center column, were used in this research. The test tank represents a 1/10.85 scaled version of an 85 foot diameter, Type IIIA, nuclear waste tank that may be typical of Blend Tanks used in SDI. Specifically, Tank 50 was selected as the tank to be modeled per the SRR, Project Engineering Manager. SRNL blending tests investigated various fixed position, non-rotating, dual nozzle pump designs, including a blending pump model provided by the blend pump vendor, Curtiss Wright (CW). Primary research goals were to assess blending times and to evaluate incipient sludge disturbance for waste tanks. Incipient sludge disturbance was defined by SRR and SRNL as minor blending of settled sludge from the tank bottom into suspension due to blending pump operation, where the sludge level was shown to remain constant. To experimentally model the sludge layer, a very thin, pourable, sludge simulant was conservatively used for all testing. To experimentally model the liquid, supernate layer above the sludge in waste tanks, two salt solution simulants were used, which provided a bounding range of supernate properties. One solution was water (H{sub 2}O + NaOH), and the other was an inhibited, more viscous salt solution. The research performed and data obtained significantly advances the understanding of fluid mechanics, mixing theory and CFD modeling for nuclear waste tanks by benchmarking CFD results to actual experimental data. This research significantly bridges the gap between previous CFD models and actual field experiences in real waste tanks. A finding of the 2009, DOE, Slurry Retrieval, Pipeline Transport and Plugging, and Mixing Workshop was that CFD models were inadequate to assess blending processes in nuclear waste tanks. One recommendation from that Workshop was that a validation, or bench marking program be performed for CFD modeling versus experiment. This research provided experimental data to validate and correct CFD models as they apply to mixing and blending in nuclear waste tanks. Extensive SDI research was a significant step toward bench marking and applying CFD modeling. This research showed that CFD models not only agreed with experiment, but demonstrated that the large variance in actual experimental data accounts for misunderstood discrepancies between CFD models and experiments. Having documented this finding, SRNL was able to provide correction factors to be used with CFD models to statistically bound full scale CFD results. Through the use of pilot scale tests performed for both types of pumps and available engineering literature, SRNL demonstrated how to effectively apply CFD results to salt batch mixing in full scale waste tanks. In other words, CFD models were in error prior to development of experimental correction factors determined during this research, which provided a technique to use CFD models for salt batch mixing and transfer pump operations. This major scientific advance in mixing technology resulted in multi-million dollar cost savings to SRR. New techniques were developed for both experiment and analysis to complete this research. Supporting this success, research findings are summarized in the Conclusions section of this report, and technical recommendations for design and operation are included in this section of the report.

Document type: Report

Information propagation speed versus transport capacity in mobile ad hoc wireless networks

Scipedia content — Thu, 22 Oct 2020 15:46:27 +0200

We give an estimate of an upper bound of information propagation speed as a function of a targeted transport capacity density. The propagation speed depends on the density of simultaneous emitters and the node mobility model. We assume that nodes move according to an independent random walk. This work makes the junction between the work of Gupta and Kumar~(2000) and Grossglauser and Tse~(2002). We show that the information speed tends to zero when the transport capacity tends to infinity. We compare our result to the performance of an actual protocol based on angle determination.; Nous donnons une borne supérieure de la vitesse de propagation en fonction d'une capacité de transport ciblée. La vitesse de propagation dépend de la densité des émetteurs et de la mobilité des postes. Nous supposons fait la jonction entre les travaux de Gupta et Kumar (2000) et ceux de Grossglauser et Tse (2002). Nous montrons que la vitesse de propagation tend vers zero quand la capacité de transport tend vers l'infini. Nous comparons avec les performances d'un algorithme réaliste basé sur des angles.

Document type: Report

Scalable internet architecture supporting quality of service qos

Scipedia content — Wed, 14 Oct 2020 16:38:29 +0200

The evolution of Internet and its successful technologies has brought a tremendous growth in business, education, research etc. over the last four decades. With the dramatic advances in multimedia technologies and the increasing popularity of real-time applications, recently Quality of Service (QoS) support in the Internet has been in great demand. Deployment of such applications over the Internet in recent years, and the trend to manage them efficiently with a desired QoS in mind, researchers have been trying for a major shift from its Best Effort (BE) model to a service oriented model. Such efforts have resulted in Integrated Services (Intserv), Differentiated Services (Diffserv), Multi Protocol Label Switching (MPLS), Policy Based Networking (PBN) and many more technologies. But the reality is that such models have been implemented only in certain areas in the Internet not everywhere and many of them also faces scalability problem while dealing with huge number of traffic flows with varied priority levels in the Internet. As a result, an architecture addressing scalability problem and satisfying end-to-end QoS still remains a big issue in the Internet. In this chapter the authors propose a policy based architecture which they believe can achieve scalability while offering end to end QoS in the Internet.

Document type: Part of book or chapter of book

Modelling and Analysis of Distributed Energy Systems with Respect to Sustainable Energy:Focus on Electric Drive Vehicles

Scipedia content — Wed, 14 Oct 2020 16:36:37 +0200

Climate change and CO2 emissions is an important issue on the agenda of many politicians. Trying to decrease CO2 emissions, influences transportation, power production, etc. The power system is characterised by an increasing amount of renewables, with one of the most expanding renewable power sources being wind. Wind energy is fluctuating by nature, calling for increasing flexibility elsewhere in the energy system. For Denmark, hydro power from Norway help stabilizing the system, as does export of excess wind to Germany, although the latter is decreasing in use because of large correlations between high wind production in northern Germany and western Denmark. To decrease CO2 emissions through a decrease in the use of fossil fuelled plants, along with an increase the amount of renewable energy, the power system needs more flexibility such as flexible demands, storage etc. Flexibility could also come from the road transport system. Counting for 24% of the CO2 emissions in Denmark in 2009, the road transport system needs to move towards, e.g. electric drive vehicles. However, the electric drive vehicles are also demanding electricity from the power system. This brings both challenges and opportunities to the power system. One challenge is, that intelligence is needed unless peak-load is to increase drastically. With intelligent charging of the vehicles, though, the electric drive vehicles can be of great benefit providing flexible demand and charging at night time, instead of being regarded as yet another load and challenge for the energy system. Furthermore, discharging of vehicles can provide services to the power system. The batteries in the electric drive vehicles are batteries invested in anyway. Hence, why not use these actively for cheap storage by the energy system? Furthermore, the use of vehicles are opposite to the remaining demand for energy; e.g. while people are making dinner their vehicles will often be parked, being able to deliver back-up power - again, a great opportunity for the power system. In this PhD project I have focussed on modelling and analysis of a future integrated transport and power system. An integrated power and transport system enables analyses of the interactions between different parts of the energy system. The object of interest is an optimal configuration of an integrated power and transport system as well as I will be focussing on the drawbacks and benefits for the power system incorporating an electrified transport system. I have performed analyses in terms of integrating more renewable energy, for both Denmark as an isolated system and for the northern European countries including Denmark, Sweden, Norway, Finland, and Germany. The analyses are performed using the deterministic energy systems analysis model, Balmorel. Furthermore, analyses have been made for the Irish power system on the influence of introducing electric drive vehicles in a predefined power system, using the stochastic energy systems analysis model, Wilmar. Interesting is, that it turns out to be most profitable to invest in enough wind to more than cover the electrified transport in Denmark. This holds, both when modelling Denmark as an isolated country, and when including the interactions between the Nordic countries. Furthermore, analyses show that fuel cell electric vehicles are not yet ready for competing with the other vehicle types. This is, among other things, due the technologies not being cheap enough, thus, the development is not expected to have reached a competitive stage. Another interesting finding is the results showing that it is beneficial for Ireland to have electric drive vehicles in terms of both costs and CO2 emissions. However, introducing the electric drive vehicles in Ireland, imply an increase in both costs and CO2 in the Great British side, as most of the power for the vehicles is produced on British coal power plants. Thus, focusing nationally, Ireland should invest in the electric drive vehicles, although, on an international level, the investments are costly.

Document type: Book

Interoperability Among Heterogeneous Networks for Future Aeronautical Communications

Scipedia content — Wed, 14 Oct 2020 16:36:23 +0200

Air traffic in Europe is expected to double by 2025 according to the last forecast of EUROCONTROL, with an average growth of 2.7%-3.7% per year. On a worldwide basis, the number of passengers is expected to grow by 4.5% per year over the same timeframe. Future passenger and freight fleets will bring higher efficiency and improved environmental performance, and will allow people all around the world to benefit from the essential connections that only air transport can deliver. (European Organisation for the Safety of Air Navigation [EUROCONTROL], 2006) Till recently Aeronautical Telecommunication Network (ATN) communications predominantly across continental regions used narrowband Very High Frequency (VHF) voice systems along with digital data links like the VHF Digital Link (VDL) Mode 2 (ICAO, 2001) and Aircraft Communications Addressing and Reporting System (ACARS) (ARINC, 2011). Such narrowband air-ground data link technologies have several limitations like the susceptibility to access collisions, lack of data prioritization mechanism at the sub-network level and also the vulnerability of jamming in narrowband communication channels. Hence, other High Frequency (HF) radio link technology like the ARINC GLOBALink (Homans, 2002) and also satellite based system like the INMARSAT SwiftBroadband systems have been used to provide voice and data communications between the aircraft and the ground control centres (EUROCONTROL, 2006). A detailed study on the various communications systems suitable for Air Traffic Management (ATM) systems was carried out by the Federal Aviation Administration (FAA) and EUROCONTROL with the support of NASA (NASA, 2005). It highlighted the advantages and disadvantages of the various communications systems and showed that it is important for the future ATN communication systems to provide fast, high-speed and high-data rate reliable communications not only between the aircraft and ground infrastructure but also between airplanes directly. Hence it is envisaged that in order to provide the most efficient form of reliable ATM communications, different heterogeneous networks need to be adopted. It is also envisaged that future aeronautical communication systems would be able to simultaneously operate the different radio communication technologies. The different technologies will provide various advantages and provide the flexibility to the system to provide very high reliability. Hence different data i.e. Air Traffic Service (ATS), Airline Operation Centre (AOC), Airline Administrative

Document type: Part of book or chapter of book

Dealing with known unknowns towards a game theoretic foundation for software requirement evolution

Scipedia content — Wed, 14 Oct 2020 16:34:41 +0200

Requirement evolution has drawn a lot of attention from the community with a major focus on management and consistency of requirements. Here, we tackle the fundamental, albeit less explored, alternative of modeling the future evolution of requirements.\r \r Our approach is based on the explicit representation of controllable evolutions vs observable evolutions, which can only be estimated with a certain probability. Since classical interpretations of probability do not suit well the characteristics of software design, we introduce a game-theoretic approach to give an explanation to the semantic behind probabilities. Based on this approach we also introduce quantitative metrics to support the choice among evolution-resilient solutions for the system-to-be.\r \r To illustrate and show the applicability of our work, we present and discuss examples taken from a concrete case study (the security of the SWIM system in Air Traffic Management).

Document type: Part of book or chapter of book

Results Readiness in Social Protection and Labor Operations

Scipedia content — Wed, 14 Oct 2020 16:27:46 +0200

The main focus of the social protection and labor portfolio is on strengthening client's institutional capacity in the design and implementation of programs, but projects are not well equipped to track progress in this area. Correspondingly, there is a need to strengthen approaches to measuring and monitoring a 'missing middle' of service delivery, precisely those areas for which counterpart institutions are responsible during the course of a project. In particular, better measures of the primary functions of social protection and labor agencies are needed, such as identifying and enrolling beneficiaries, targeting, payment systems, fraud and error control, performance monitoring of service delivery providers, responsiveness to citizens, transparency, efficiency, management information systems and monitoring and evaluation systems. New World Bank initiatives particularly standard core indicators by sector and the introduction of results based investment lending call for substantial improvements in the use of monitoring and evaluation (M&E). Impact evaluations are included in about half of projects and should continue to be used selectively and strategically, particularly when the program is innovative, replicable and/ or scalable to reach a broader set of beneficiaries, addresses a knowledge gap and is likely to have a substantial policy impact. Structuring evaluations around core themes with common outcome measures is fundamental to building a global knowledge base on development effectiveness.

Document type: Book

Flow Allocation Algorithms for Traffic Engineering

Scipedia content — Wed, 14 Oct 2020 16:22:16 +0200

The objective of traffic engineering (TE) is to optimize network resources, while satisfying traffic-oriented performance requirements. As a technology for TE, we focus on a method by which to avoid congestion on some links and balance the traffic load over the network. Given a traffic matrix representing traffic demands, we allocate their traffic flows over the network. In this paper, we propose a number of flow allocation algorithms for TE in ISP backbone networks. As an objective function, we employ the maximum link utilization. We then evaluate the effect of the proposed algorithms with respect to load balancing and compare the performance of these algorithms.

Document type: Part of book or chapter of book

How a fast lane may replace a congestion toll

Scipedia content — Wed, 14 Oct 2020 16:21:43 +0200

This paper considers a congested bottleneck. A fast lane reserves a more than proportional share of capacity to a designated group of travellers. Travellers are otherwise identical and other travellers can use the reserved capacity when it would otherwise be idle. The paper shows that such a fast lane is always Pareto improving under Nash equilibrium in arrival times at the bottleneck and inelastic demand. It can replicate the arrival schedule and queueing outcomes of a toll that optimally charges a constant toll during part of the demand peak. Within some bounds, the fast lane scheme is still welfare improving when demand is elastic.

Document type: Book

Effective regulatory institutions for air transport

Scipedia content — Wed, 14 Oct 2020 16:19:36 +0200

The heated debate on the regulatory framework for airports has highlighted the importance of creating good institutions for air transport in general. This paper defines the concept of effective regulatory institutions for air transport. It also describes the value chain for air transport and how the state intervenes with what type of regulatory institution. The paper concludes by highlighting the institutional reforms necessary to make regulation effective.

Document type: Part of book or chapter of book

Implementation of quality of service in voip

Scipedia content — Wed, 14 Oct 2020 16:18:28 +0200

Today, Internet technologies have pervaded every corner of our society. More and more people are benefiting from the Internet in one way or the other. One of the current Internet technologies that may benefit us greatly is voice over Internet protocol (VoIP). According to Hardy (2003, p. 2), VoIP is the interactive voice exchange capability carried over packet-switched transport employing the Internet protocol. With VoIP technology, one can call anyone in this world at a lower cost, compared to traditional telephone systems. However, VoIP technology has one significant drawback. It has a low degree of reliability. From experimental results it is known that VoIP can achieve only 98% reliability. The service down time per year for VoIP is almost 20 working days (175 hours). For most companies and government organizations, such a degree of reliability is unacceptable since the traditional telephone system can achieve 99.999% reliability with a service down time of only five minutes per year (Kos, Klepec, & Tomaxic, 2005). As a result, quality of service (QoS) is an important concept for VoIP. Using QoS, VoIP may be able to overcome its limitation in reliability. QoS is often defined as the capability to provide resource assurance and service differentiation in a network. The definition includes two important termsresource assurance and service differentiation. Resource assurance provides a guarantee about the amount of network resources requested by the user. On the other hand, service differentiation provides higher priority of getting network resources to those applications that have critical latency constraints. Given the importance of low latency for voice communication, it is not difficult to predict that QoS will assume greater importance in the VoIP industry as this technology gains popularity in the mass market. It is reported that VoIP is aggressively growing, and this growth is expected to continue in the coming years.

Document type: Part of book or chapter of book

The Effect of Congestion Frequency and Saturation on Coordinated Traffic Routing

Scipedia content — Wed, 14 Oct 2020 16:15:35 +0200

Traffic congestion is a widespread epidemic that continually wreaks havoc in urban areas. Traffic jams, car wrecks, construction delays, and other causes of congestion, can turn even the biggest highways into a parking lot. Several congestion mitigation strategies are being studied, many focusing on micro-simulation of traffic to determine how modifying road structures will affect the flow of traffic and the networking perspective of vehicle-to-vehicle communication. Vehicle routing on a network of roads and intersections can be modeled as a distributed constraint optimization problem and solved using a range of centralized to decentralized techniques. In this paper, we present a constraint optimization model of a traffic routing problem. We produce congestion data using a sinusoidal wave pattern and vary its amplitude (saturation) and frequency (vehicle waves through a given intersection). Through empirical evaluation, we show how a centralized and decentralized solution each react to unknown congestion information that occurs after the initial route planning period.

Document type: Part of book or chapter of book

Nigeria 2011

Scipedia content — Wed, 14 Oct 2020 16:12:07 +0200

This investment climate analysis reviews the experiences of over 3000 surveyed business owners in 26 states of Nigeria about the aspects of the business climate that affect their businesses. It complements a similar study in 2007 that covered 11 other Nigerian states. The survey asks business owners about both their perceptions and the actual costs of selected constraints. The analysis benchmarks Nigeria against comparator countries, and provides detailed data for each state. Nigerian firms have low productivity, as measured by their output in relation to their labor and capital inputs. Firms in Kenya are about 40 percent more efficient, firms in Russia almost twice as productive, and firms in South Africa almost four times as productive. Nigerian firms that export are about 90 percent more productive than non-exporters. Although labor in Nigeria is inexpensive, it is not inexpensive enough to compensate for this low productivity. The poor performance of Nigerian firms reflects many factors. This study focuses on constraints in the business climate and the serious costs they impose on Nigerian firms. Taken together, the total indirect costs of poor quality infrastructure, crime and security, and corruption amount to over 10 percent of sales for Nigerian firms. This is twice as high as in South Africa, Brazil, Russia and Indonesia. Microenterprises firms with fewer than five workers face similar constraints as larger firm's unreliable power, limited access to finance, corruption, and transportation bottlenecks. But the consequences for their businesses are far more severe. For instance, most microenterprises cannot afford generators, so power outages are more likely to shut down their operation. Lacking collateral, almost no microenterprises have access to formal external financing.

Document type: Book

The Republic of Congo's Infrastructure: A Continental Perspective

Scipedia content — Wed, 14 Oct 2020 16:06:49 +0200

Upgrading infrastructure plays a critical role in the Republic of Congo's quest to diversify its economy and reduce poverty. It is also an important source of growth on its own. A cross-country statistical analysis conducted for this report shows that infrastructure contributed one-half of one percentage point to the Republic of Congo's per capita gross domestic product (GDP) growth annually from 2001 to 2006. However, if the country's infrastructure could be improved to the level seen in Mauritius, the leading country in Sub-Saharan Africa, it could contribute more than 3 percentage points to annual per capita growth. The Republic of Congo's power infrastructure is inadequate and inefficiently operated. The country lags well behind peer countries in generation capacity and electrification. The parts of the population not served by the grid face exorbitant costs. The government has responded to these issues with an ambitious investment plan. However, if new assets are to operate effectively, major inefficiencies in the power utility will also need to be addressed. The utility's transmission and distribution losses are 47 percent, more than double best-practice benchmarks, while the cost of overstaffing is 30 percent of utility revenue. Tariffs recover barely half the cost of service provision, even though full cost recovery will be affordable to the population. In the information and communication technology (ICT) sector, the Republic of Congo has made good progress in developing its mobile telephony market in recent years, with high levels of signal coverage. The cost of international connectivity is currently high, but it should fall once the country connects to the international submarine cable and completes its domestic fiber optic network. On the other hand, the physically dilapidated and financially depleted condition of the fixed-line telephone operator is becoming a constraint to raising Internet penetration. The Republic of Congo performs relatively well on service coverage in the water and sanitation sector. The country's access statistics are substantially ahead of those in its peer group, particularly with regard to piped water, stand-posts, and improved latrines. However, access to services is much greater in urban areas than in rural areas. Furthermore, under-pricing of water has hurt the financial soundness of the water utility, even though analysis suggests that cost recovery tariffs would be affordable to consumers.

Document type: Book

Using Provenance to Support Good Laboratory Practice in Grid Environments

Scipedia content — Wed, 14 Oct 2020 15:58:05 +0200

Conducting experiments and documenting results is daily business of scientists. Good and traceable documentation enables other scientists to confirm procedures and results for increased credibility. Documentation and scientific conduct are regulated and termed as "good laboratory practice." Laboratory notebooks are used to record each step in conducting an experiment and processing data. Originally, these notebooks were paper based. Due to computerised research systems, acquired data became more elaborate, thus increasing the need for electronic notebooks with data storage, computational features and reliable electronic documentation. As a new approach to this, a scientific data management system (DataFinder) is enhanced with features for traceable documentation. Provenance recording is used to meet requirements of traceability, and this information can later be queried for further analysis. DataFinder has further important features for scientific documentation: It employs a heterogeneous and distributed data storage concept. This enables access to different types of data storage systems (e. g. Grid data infrastructure, file servers). In this chapter we describe a number of building blocks that are available or close to finished development. These components are intended for assembling an electronic laboratory notebook for use in Grid environments, while retaining maximal flexibility on usage scenarios as well as maximal compatibility overlap towards each other. Through the usage of such a system, provenance can successfully be used to trace the scientific workflow of preparation, execution, evaluation, interpretation and archiving of research data. The reliability of research results increases and the research process remains transparent to remote research partners.

Document type: Part of book or chapter of book

Niger s infrastructure a continental perspective

Scipedia content — Wed, 14 Oct 2020 15:54:07 +0200

Between 2000 and 2005 infrastructure made a net contribution of only 0.3 percentage points to the improved per capita growth performance of Niger, one of the lowest in Sub-Saharan Africa. Raising the country's infrastructure endowment to that of the region's middle-income countries (MICs) could boost annual growth by about 4.5 percentage points, mainly by improving the condition of the road network. Niger has made significant progress in some areas of its infrastructure. Important reforms liberalizing the water supply and information and communication technology (ICT) sectors have boosted performance. In particular, reforms in urban water are among the most promising on the continent. Increased competition in the ICT market has contributed to the rapid expansion of mobile services. NIGELEC, the national power utility, has enhanced its performance. The Nigerien portions of regional corridors are in relatively good or fair condition. Air transport connectivity has improved. Niger has the potential to close this funding gap by tapping alternate sources of financing or adopting lower-cost technologies. There is plenty of room for private sector participation in Niger's infrastructure sectors, in particular ICT. Meanwhile, the adoption of alternate lower-cost technologies in the water supply, power, and road sectors would reduce the financing gap by almost a half ($219 million).

Document type: Book

Eco methodology for urban and transport planning for the future eco technology

Scipedia content — Wed, 14 Oct 2020 15:53:41 +0200

This study gives the reasons and basics of a new approach which adopts eco-technologies to urban and transport planning. In this chapter, in the case of urban and transport planning, based on research findings about human behaviour in the artificial and technical modified environment, the discrepancy between assumptions and real system behaviour is demonstrated. This gives the framework not only to improve urban structures and the transport system, but also to select (eco) technologies which are needed to solve existing problems and to develop agreeable technologies for the future. The study criticizes the use of technology in creating vulnerable urban structures instead of sustainable ones focusing mostly on the last 150 years, when the availability of cheap fossil fuels for use of new transport modes and for heating and cooling has changed urban life. The resulting part is the introduction of a new methodology which uses eco technologies in urban and transport planning with some success stories.

Document type: Part of book or chapter of book

Hazardous materials transportation

Scipedia content — Wed, 14 Oct 2020 15:49:36 +0200

This chapter describes how the U.S. Department of Transportation (US DOT) defines a hazardous material as any substance or material capable of causing harm to people, property, and the environment. Dependence on hazardous materials is a fact of life in industrialized societies. There are thousands of different hazardous materials in use today. The United Nations sorts hazardous materials into nine classes according to their physical, chemical, and nuclear properties: explosives and pyrotechnics; gases; flammable and combustible liquids; flammable, combustible, and dangerous-when-wet solids; oxidizers and organic peroxides; poisonous and infectious materials; radioactive materials; corrosive materials; and miscellaneous dangerous goods, such as hazardous wastes. This first section of the chapter describes how the transportation of hazmats can be classified according to the mode of transport, namely; road, rail, water, air, and pipeline. The next section offers a high-level view of hazmat logistics literature. Section 3 contains a treatment of risk, the main ingredient of hazmat logistics problems that separate them from other logistics problems and section 4 deals with hazmat routing and scheduling problems. Section 5 focuses on models that combine undesirable facility location and hazmat transportation. The final section offers a critique of the existing literature and suggests directions for future research.

Document type: Part of book or chapter of book

Development of a cost model for intermodal transport in Spain

Scipedia content — Wed, 14 Oct 2020 15:45:04 +0200

For several years, the promotion of intermodal transport has been a priority for the Spanish and European authorities (Cuerda et al., 2003; Conseil National des Transports [CNT], 2005) but the importance and the recent growth of rail transport in Spain is extremely small compared to road transport. This is more so in the case of small and medium-size companies shipping general (non-bulk) cargo, which almost exclusively use the road (Ministerio de Fomento, 2004). The establishment of a network of intermodal freight transport centres connected to the main railway lines and close to the main cities is viewed as an opportunity for the modal shift, and also the establishment of relevant intermodal corridors dedicated to specific freight purposes (ore, agricultural products), to be defined at a European level, should improve the overall figures. But nevertheless, there is the feeling in Spain that more attention should be given to general traffic issues, facing the needs of the great amount of small companies moving small amounts of freight, but with an enormous aggregate effect. Thus the strategic objectives of our work lie within the rationalization of mobility and the improvement of intermodal accessibility. They concentrate on establishing the basis for a higher participation of small and medium-size companies in intermodal transport by analyzing the specific experiences of an individual transport company, based in the city of Seville, seeking an enhancement of the modal shift within its logistic operations. This work is organized as follows: In section 2 we describe the role of intermodal transport in the supply chain. In Section 3 we list the actors involved in all phases of intermodal transport to then show the decision-making model for each one of these actors. In Section 4 we apply this model to the case of a transport company based in the South of Spain, describing all the shipment and cost data. Finally, in section 6 we explain our conclusions drawn from the decision making model in general and in particular for the case-study company, and analyze the effect of additional factors (other than cost) in the decision-making process with respect to intermodal transport.

Document type: Part of book or chapter of book

Logistics Costs and Competitiveness : Measurement and Trade Policy Applications

Scipedia content — Wed, 14 Oct 2020 15:44:51 +0200

This paper examines the issue of measuring logistics costs from an applied trade policy research perspective, as well as identifying logistics-intensive sectors. It focuses on currently available data at the macro-and firm-levels. This paper has two main aims. First, it provides a first overview of currently available data relevant to logistics, and suggests some preliminary applications. The second objective of this paper is to frame the issue of logistics cost measurement and data collection in terms of the types of inputs needed for applied trade policy research. The paper is organized as follows. The next section presents an overview of possible directions in applied trade policy research using logistics data. Section three examines existing data sources that can be used to measure domestic logistics costs, focusing on the national accounts, input-output tables, price comparisons, and firm-level data. Section four presents a new methodology for measuring international trade costs, and identifies the proportion of those costs due to logistics. Section five uses input-output data to identify logistics-intensive sectors in a range of countries. Section six concludes. This paper has explored a number of different data sources and methodologies in an effort to move forward on the analysis of logistics costs from a trade policy research perspective. In the future, it will be important to distinguish between data collection efforts that are industry-driven-such as estimates of total logistics costs in Gross Domestic Product (GDP)-and those that are research-driven. Moving further in this direction will help fuel research that identifies sectors in particular countries that are most sensitive to improvements in logistics performance, and which therefore will tend to expand relative to other sectors in the face of logistics sector reforms. From a policy and political economy point of view, it will be important to identify such sectors and make them aware of the potential role logistics can play in facilitating their growth.

Document type: Book

Balancing by preflex congestion aware traffic engineering

Scipedia content — Wed, 14 Oct 2020 15:43:08 +0200

Part 3: Resource Allocation; International audience; There has long been a need for a robust and reliable system which distributes traffic across multiple paths. In particular such a system must rarely reorder packets, must not require per-flow state, must cope with different paths having different bandwidths and must be self-tuning in a variety of network contexts. PREFLEX, proposed herein, uses estimates of loss rate to balance congestion. This paper describes a method of automatically adjusting how PREFLEX will split traffic in order to balance loss across multiple paths in a variety of network conditions.Equations are derived for the automatic tuning of the time scale and traffic split at a decision point. The algorithms described allow the load balancer to self-tune to network conditions. The calculations are simple and do not place a large burden on a router which would implement the algorithm. The algorithm is evaluated by simulation using ns-3 and is shown to perform well under a variety of circumstances. The resulting adaptive, end-to-end traffic balancing architecture provides the necessary framework to meet the increasing demands of users while simultaneously offering edge networks more fine-grained control at far shorter timescales.

Document type: Part of book or chapter of book

Interface Layers Detection in Oil Field Tanks: A Critical Review

Scipedia content — Wed, 14 Oct 2020 15:42:53 +0200

An emulsion layer is a mixture of two or more liquids in which one of them the dispersed phase, is present as droplets of microscopic size, distributed throughout the other, called continuous phase. The existence of such layer between oil and water is due to the crude properties, and contaminants such as asphaltenes and resins. A measurement system to determine the boundaries of this emulsion in a modern oil production field is necessary to extract the pure single phase liquids [1, 2, 3]. This would for instance reduce the usage of expensive two phase flow meters and avoid the installation of additional tank separators along the upstream oil pipeline. In addition, this would help collecting accurate daily oil production statistics from each oil station. One widely deployed solution consists to inject chemical substances to completely eliminate the emulsion layer and leave only a crisp oilwater interface which can then be detected relatively much more easier. However, this approach is costly, not environmental friendly, and leads to a significant increase of the retention time in the separator. This book chapter provides a survey on electronic-basedtechniques which are capable to measure the high and low boundaries of the emulsion layer in real-time. It then describes in more details a new ultrasonic-based device along with the experimental results it could provide.

Document type: Part of book or chapter of book

Is it what you inherited or what you learnt intergenerational linkage and interpersonal inequality in senegal

Scipedia content — Wed, 14 Oct 2020 15:42:39 +0200

Institutional features of the African setting -- large extended families and imperfect credit and land markets -- matter to the equity and efficiency roles played by intergenerational linkages. Using original survey data on Senegal that include an individualized measure of consumption, this paper studies the role played by land inheritance, other bequests and parental background as influences on an adult's economic welfare and economic activities. Although intergenerational linkages are evident, the analysis finds a seemingly high degree of mobility across generations, associated with the shift from farm to non-farm sectors and the greater economic activity of women. Male-dominated bequests of land and housing bring little gain to mean consumption and play little role in explaining inequality, although they have effects on the sector of activity. Inheritance of non-land assets and the education and occupation of parents (especially the mother) and their choices about children's schooling are more important to adult welfare than property inheritance. Significant gender inequality in consumption is evident, although it is almost entirely explicable in terms of factors such as education and (non-land) inheritance. There are a number of other pronounced gender differences, with intergenerational linkages coming through the mother rather than the father.

Document type: Book

Ghana's Infrastructure : A Continental Perspective

Scipedia content — Wed, 14 Oct 2020 15:41:13 +0200

Infrastructure contributed just over one percentage point to Ghana's improved per capita growth performance during the 2000s, though unreliable power supplies held growth back by 0.5 percentage points. Raising the country's infrastructure endowment to that of the region's middle-income countries could boost annual growth by more than 2.7 percentage points. Today, Ghana has a very advanced infrastructure platform when compared with other low-income countries in Africa. But as the country approaches the middle-income threshold, it will need to focus on upgrading its infrastructure indicators in line with this benchmark. The Africa Infrastructure Country Diagnostic (AICD) has gathered and analyzed extensive data on infrastructure in more than 40 Sub-Saharan countries, including Ghana. The results have been presented in reports covering different areas of infrastructure, including ICT, irrigation, power, transport, water, and sanitation, and different policy areas, including investment needs, fiscal costs, and sector performance. This report presents the key AICD findings for Ghana and allows the country's infrastructure situation to be benchmarked against its African peers. Given that Ghana is a relatively well-off low-income country well on its way to reaching middle-income status, two sets of African benchmarks will be used to evaluate Ghana's situation. Detailed comparisons will also be made with immediate regional neighbors in the Economic Community of West African States (ECOWAS). As on the rest of the continent, West Africa's growth performance improved markedly in the 2000s. The overall improvement in per capita growth rates has been estimated at around 2 percent, of which 1.1 percent is attributable to better structural policies and 0.9 percent to improved infrastructure. During the five years from 2003 to 2007, Ghana's economy grew at an average annual rate of 5.6 percent, which accelerated to 7.3 percent in 2009. Ghana's infrastructure improvements added just over one percentage point to the per capita growth rate for the period 2003 to 2007.

Document type: Book

Stochastic traffic engineering for live audio/video delivering over energy-limited wireless access networks

Scipedia content — Wed, 14 Oct 2020 15:40:04 +0200

Part 4: Energy Efficiency International audience We study the Stochastic Traffic Engineering (STE) problem arising from the support of QoS-demanding live (e.g., real time) audio/video applications over unreliable IP-over-wireless access pipes. First, we recast the problem to be tackled in the form of a suitable nonlinear stochastic optimization problem, and then we develop a goodput analysis for the resulting IP-over-wireless pipe that points out the relative effects of fading-induced errors and congestion-induced packets losses. Second, we present an optimal resource-management policy that allows a joint scheduling of playin, transmit and playout rates. Salient features of the developed joint scheduling policy are that: i) it is self-adaptive; and, ii) it is able to implement reliable Constant Bit Rate (CBR) connections on the top of unreliable energy-limited wireless pipes.

Document type: Part of book or chapter of book

Harbour Light. Port and transport related EU policy and regulations: The professionals' guide

Scipedia content — Wed, 14 Oct 2020 15:39:14 +0200

Document type: Book

Plug and play transport chain management agent based support to the planning and execution of transports

Scipedia content — Wed, 14 Oct 2020 15:38:29 +0200

A novel approach to efficiently plan and execute effective transport solutions is presented. It provides agent-based support for key tasks, such as, finding the best sequence of transport services for a particular goods transport, monitoring the execution of the transport, as well as the interaction between the involved actors. The approach is based on the FREIGHTWISE framework in which a minimal set of information packages is defined. The purpose is to capture all the information that needs to be communicated between the actors involved in a transport, such as, transport users, transport providers, and infrastructure managers, during the complete process from planning to termination. The approach is inspired by the concepts of virtual enterprises and breeding environments. We analyse the requirements of such an approach and describe a multi-agent system architecture meeting these requirements.

Document type: Part of book or chapter of book

Live and work in North Denmark:Expat Survey 2012

Scipedia content — Wed, 14 Oct 2020 15:33:12 +0200

This report is based on a survey among Expats in North Denmark, and was carried out in collaboration with 'Velkomstcentre - live and work in North Denmark'. It includes findings about the backgrounds of the Expats, their motives for coming to the region and their perceptions of the region before and after moving to North Denmark.

Document type: Book

Dataflow and remapping for wavelet compression and view dependent optimization of billion triangle isosurfaces

Scipedia content — Wed, 14 Oct 2020 15:31:54 +0200

Currently, large physics simulations produce 3D discretized field data whose individual isosurfaces, after conventional extraction processes, contain upwards of hundreds of millions of triangles. Detailed interactive viewing of these surfaces requires (a) powerful compression to minimize storage, and (b) fast view-dependent optimization of display triangulations to most effectively utilize high-performance graphics hardware. In this work, we introduce the first end-to-end multiresolution dataflow strategy that can effectively combine the top performing subdivision-surface wavelet compression and view-dependent optimization methods, thus increasing efficiency by several orders of magnitude over conventional processing pipelines. In addition to the general development and analysis of the dataflow, we present new algorithms at two steps in the pipeline that provide the glue that makes an integrated large-scale data visualization approach possible. A shrink-wrapping step converts highly detailed unstructured surfaces of arbitrary topology to the semi-structured meshes needed for wavelet compression. Remapping to triangle bintrees minimizes disturbing pops during realtime displaytriangulation optimization and provides effective selective-transmission compression for out-of-core and remote access to extremely large surfaces. Overall, this is the first effort to exploit semi-structured surface representations for a complete large-data visualization pipeline.

Document type: Part of book or chapter of book

Sierra Leone's Infrastructure: A Continental Perspective

Scipedia content — Wed, 14 Oct 2020 15:29:51 +0200

Infrastructure has contributed significantly to the growth of West African economies during the past decade. In Sierra Leone, infrastructure added only around 0.51 percentage points to the per capita growth rate over 2003-07. Similarly to other countries in the region and the rest of the continent, the boost to historic growth came predominately from the ICT (Information and Telecommunications Technology) revolution while power-sector deficiencies and poor roads held back growth. After nine years of peace, economic activity is flourishing at every level in Sierra Leone. Political stability, high government accountability, good governance standards, and streamlined tax reform helped Sierra Leone to become a bright success story, turning the country into the easiest and quickest place to start business in West Africa. Sierra Leone's image in the eyes of investors is strengthened as the country ranked as one of the top five countries in Africa for investor protection. Looking ahead, the country faces a number of critical infrastructure challenges. Perhaps the most daunting of these challenges lies in the power sector, the poor state of which retards development of other sectors. Access to power is very low, at around 1 to 5 percent in urban areas, and is nonexistent in the countryside. The country's installed power-generation capacity is around 13 megawatts per million people, which is lower than what other low-income and fragile states have installed. The entire existing power infrastructure is concentrated in the western part of the country, and even with the functioning of the Bumbuna power plant, only half the suppressed demand for Freetown, let alone that for the rest of the country, is being met. Regardless of recent reduction in tariffs, Sierra Leoneans still pay some of the highest tariffs in Africa. In 2010, Sierra Leoneans paid three times as much for power as did residents of African countries that relied on hydropower. Making investments in more cost-effective power generation options is therefore an important strategic objective for Sierra Leone, without which further electrification will simply be unaffordable for the wider population.

Document type: Book

Rescue an integrated method for specifying requirements for complex sociotechnical systems

Scipedia content — Wed, 14 Oct 2020 15:27:29 +0200

This chapter describes RESCUE (Requirements Engineering with Scenarios for a User-centred Environment), a method for specifying requirements for complex sociotechnical systems that integrates human activity modeling, creative design workshops, system goal modeling using the i* notation, systematic scenario walkthroughs, and best practice in requirements management. This method has been, and is being applied in, specifying requirements for three separate systems in the domain of air traffic control. In this chapter we present examples showing how the method can be applied in the context of a case study involving the specification of requirements for Countdown, a system to provide bus passengers with information about expected bus arrival times. While this system shares some important similarities with systems used in air traffic control, we hope it is small and familiar enough to readers to provide meaningful insights into the application of the RESCUE process.

Document type: Part of book or chapter of book

Results Readiness in Social Protection and Labor Operations

Scipedia content — Wed, 14 Oct 2020 15:12:53 +0200

Social Safety Nets (SSN) are defined as non?contributory transfer programs targeted to the poor or those vulnerable to poverty and shocks. About half of World Bank social protection projects in the reviewed cohort are SSN. They are mostly non-emergency investment operations with a higher presence in Latin America and the Caribbean and Africa regions. Projects aimed at strengthening country's safety nets system, including their targeting, administration and service quality, are the most common type of SSN interventions (25 percent). These are closely followed by conditional cash transfers (20 percent), and health, nutrition and education projects (15 percent). The remaining projects are a mixture of public works; food crisis mitigation measures and other types of safety nets (social inclusion, housing, and technical assistance).

Document type: Book

Nigeria s infrastructure a continental perspective

Scipedia content — Wed, 14 Oct 2020 15:11:42 +0200

Infrastructure has made a net contribution of around one percentage point to Nigeria's improved per capita growth performance in recent years, in spite of the fact that unreliable power supply held growth back. Raising the country's infrastructure endowment to that of the region's middle-income countries could boost annual growth by around four percentage points. Nigeria has made important strides toward improving much of its infrastructure. Compared to many African peers, Nigeria has relatively advanced power, road, rail, and information and communications technology (ICT) networks that cover extensive areas of the nation's territory. In recent years, Nigeria has conducted several important infrastructure sector reforms. The ports sector has been converted to a landlord model, and terminal concessions now attract private investment on a scale unprecedented for Africa. The power sector is undergoing a restructuring, paving the way for performance improvements; the sector is finally on a path toward raising tariffs to recover a larger share of costs. Bold liberalization measures in the ICT sector have resulted in widespread, low-cost mobile services, Africa's most vibrant fixed-line sector, and major private investments in the development of a national fiber-optic backbone. A burgeoning domestic air transport sector has emerged, with strong private carriers that have rapidly attained regional significance.

Document type: Book

Reverse logistics for sustainable waste management processes

Scipedia content — Wed, 14 Oct 2020 15:09:36 +0200

This chapter highlights some of the innovative approaches that have been taken by businesses involved in reverse logistics for the removal of waste from urban areas. The chapter reviews some of these approaches and suggests which could be used more widely, recognising the specific limitations which may restrict their applicability. These innovative approaches include: the use of delivery vehicles to take-back waste/recyclate to out-of-town facilities such as a freight consolidation or recycling centre; combining commercial and household waste collections; deploying public transport vehicles to carry specialist recyclate; using multi-modal transport; smart bin technology and pipelines for the removal of waste from buildings.

Document type: Part of book or chapter of book

Benin s infrastructure a continental perspective

Scipedia content — Wed, 14 Oct 2020 15:05:07 +0200

Between 2000 and 2005 infrastructure made an important contribution of 1.6 percentage point to Benin's improved per capita growth performance, which was the highest among West African countries during the period. Raising the country's infrastructure endowment to that of the region's middle-income countries could boost annual growth by about 3.2 percentage points. Benin has made significant progress in some areas of its infrastructure. The rural road network is in relatively good condition, and about 30 percent of the rural population has access to an all-season road, a level above the country's peers. Air transport connectivity has improved. Also, important market liberalization reforms designed to attract private capital to the water and information and communications technology (ICT) sectors have boosted performance. In particular, increased competition in the ICT market has contributed to the rapid expansion of mobile and Internet services. Addressing Benin's infrastructure challenges will require sustained expenditures of $712 million per year over the next decade, with heavy emphasis on capital expenditure. Almost half of the total relates to the transport sector. At 16.6 percent of Benin's 2005 gross domestic product (GDP), this effort is almost at the level of other Sub-Saharan African countries. Benin already spends around $452 million per year on infrastructure, equivalent to about 10.5 percent of its GDP. Almost $101 million a year is lost to inefficiencies of various kinds, associated mainly with under pricing in the power and water sectors; poor financial management of utilities; and inefficient allocation of resources across sectors. If Benin could raise tariffs to cost-recovery levels, and reduce operational inefficiencies in line with reasonable developing-country benchmarks, it could substantially boost flows to the infrastructure sectors. Comparing spending needs with existing spending and potential efficiency gains (and assuming that the inefficiencies are fully captured) leaves an annual funding gap of $210 million per year. By far the largest share of the gap can be traced to the water supply and sanitation sectors. Benin has the potential to close this gap by adopting alternative technologies in water supply, transport and power. Savings from alternative technologies could amount to as much as $227 million per year.

Document type: Book

Port governance in the south west of england a comparative assessment

Scipedia content — Wed, 14 Oct 2020 14:59:51 +0200

The South West of England is a very extensive region with constraints in terms of its transport network. It is imperative if the region is to optimise its economic development for transport services to fully utilise all transport modes, not least short sea shipping. To achieve this utilisation will require, inter alia, investment in the regions port infrastructure. In addition, the region is well-placed geographically in relation to a number of other European Union countries to develop seaborne trade links with them. If this can be supported both by the development of coastal shipping links between regional ports and the incremental capability of rail and road transport within the region then substantial increased economic activity for the region could result. Moreover, it will be beneficial if the regions ports could act as a network, optimising the contribution each port can make. This in no way precludes healthy competition between the ports.

Document type: Part of book or chapter of book

A novel real time emotion detection system for advanced driver assistance systems

Scipedia content — Wed, 14 Oct 2020 14:59:40 +0200

This paper presents a real-time emotion recognition concept of voice streams. A comprehensive solution based on Bayesian Quadratic Discriminate Classifier(QDC) is developed. The developed system supports Advanced Driver Assistance Systems (ADAS) to detect the mood of the driver based on the fact that aggressive behavior on road leads to traffic accidents. We use only 12 features to classify between 5 different classes of emotions. We illustrate that the extracted emotion features are highly overlapped and how each emotion class is effecting the recognition ratio. Finally, we show that the Bayesian Quadratic Discriminate Classifier is an appropriate solution for emotion detection systems, where a real-time detection is deeply needed with a low number of features.

Document type: Part of book or chapter of book

Semantic technologies for describing measurement data in databases

Scipedia content — Wed, 14 Oct 2020 14:59:27 +0200

Exploration and analysis of vast empirical data is a cornerstone of the development and assessment of driver assistance systems. A common challenge is to apply the domain specific knowledge to the (mechanised) data handling, pre-processing and analysis process.\r \r Ontologies can describe domain specific knowledge in a structured way that is manageable for both humans and algorithms. This paper outlines an architecture to support an ontology based analysis process for data stored in databases. Build on these concepts and architecture, a prototype that handles semantic data annotations is presented. Finally, the concept is demonstrated in a realistic example. The usage of exchangeable ontologies generally allows the adaption of presented methods for different domains.

Document type: Part of book or chapter of book

Advancing adult learning in Eastern Europe and Central Asia

Scipedia content — Wed, 14 Oct 2020 14:58:36 +0200

This report presents available evidence on adult education and training in Europe and Central Asia (ECA), differentiating two separate types: continuing vocational education and training (CVET) for the employed, sought either by employers or individuals, and retraining and second chance education for the non?employed. This paper presents available evidence on the extent and patterns of lifelong learning in ECA. It argues that advancing adult education and training in ECA is important not only to meet the new skills demands but also to respond to a rapidly worsening demographic outlook across most of the region. While it is not equally important for all ECA countries, adult education and training should be high on the agenda of those ECA economies that are closest to the technological frontier and facing a demographic decline, such as the new European Union (EU) member States and Russia. The paper lays out a framework for government action to advance adult learning in ECA through a mix consisting of policy coordination between government and the enterprise sector, a sound regulatory regime and appropriate financial incentives.

Document type: Book

Malawi's infrastructure: a continental perspective

Scipedia content — Wed, 14 Oct 2020 14:58:24 +0200

Infrastructure contributed 1.2 percentage points to the annual per capita growth of Malawi's gross domestic product (GDP) over the past decade, thanks mainly to the revolution in information and communication technology (ICT). Raising the country's infrastructure endowment to that of the region's middle-income countries could further boost annual growth by 3.5 percentage points per capita. Today, Malawi's basic infrastructure indicators look relatively good when compared with other low-income countries in Africa, although the performance of that infrastructure could be significantly improved. Malawi is one of the few African countries to have already reached the Millennium Development Goals (MDGs) for water, almost a decade ahead of the target. The private sector has made Global Management System (GSM) telephone signals widely available without public subsidy. A substantial road investment program has raised the average condition of the country's road network, and a foundation for institutional reform has been laid in the ICT, power, and road transport sectors. Even if those inefficiencies could be eliminated, Malawi will still face an infrastructure funding gap of almost $300 million a year. This could be lessened to $100 million by engaging in regional trade of electricity, using lower-cost supply modalities in water supply and sanitation, and adopting appropriate technologies for road sector development. As long as efficiency gains are captured and spending sustained at the levels of the recent past, the country's infrastructure targets could be reached within 16 years.

Document type: Book

Economic importance of the Belgian ports: Flemish maritime ports, Liège port complex and the port of Brussels Report 2009

Scipedia content — Wed, 14 Oct 2020 14:57:02 +0200

This paper is an annual publication issued by the Microeconomic Analysis service of the National Bank of Belgium. The Flemish maritime ports (Antwerp, Ghent, Oostende, Zeebrugge), the Autonomous Port of Liège and the port of Brussels play a major role in their respective regional economies and in the Belgian economy, not only in terms of industrial activity but also as intermodal centres facilitating the commodity flow. This update paper provides an extensive overview of the economic importance and development of the Flemish maritime ports, the Liège port complex and the port of Brussels in the period 2004 - 2009, with an emphasis on 2009. Focusing on the three major variables of value added, employment and investment, the report also provides some information about social balance and the financial situation in these ports as a whole. These observations are linked to a more general context, along with a few cargo statistics. Annual accounts data from the Central Balance Sheet Office were used for the calculation of direct effects, the study of financial ratios and the analysis of the social balance sheet. The indirect effects of the activities concerned were estimated in terms of value added and employment, on the basis of data from the National Accounts Institute. In terms of maritime cargo traffic, the downturn recorded during the last quarter of 2008 continued throughout 2009. Direct value added declined in all the ports in Flanders. Maritime branches as a whole contracted. Only the value added of the maritime branches in the port of Ostend remained stable. The non-maritime branches as a whole saw a contraction in all the Flemish ports. It was the port of Antwerp that suffered the most from the drop in the value added. Its maritime branches shrank by nearly one third. While the non-maritime branches were slightly down. The port of Ghent recorded a bigger decrease in the non-maritime branches. Conversely, the value added in the port of Zeebrugge fell more sharply in the maritime branches. Direct employment in the ports of Flanders as a whole declined during the year 2009. Except in Ghent, direct employment in the maritime branches fell in all the Flemish ports. Similarly, only one of them, the port of Ostend, recorded a rise in employment in the non-maritime branches. Thanks to this, it has been the only Flemish port to register direct employment growth. Investment decreased in all the ports in Flanders. The decline in investment was between one-sixth and one-fifth in the ports of Ghent, Antwerp and Zeebrugge. While Ostend recorded a cut of more than one third in its investment levels in 2009. The volume of cargo handled in the port of Liège decreased strongly in 2009. Direct value added and employment registered a significant decline. Maritime and non-maritime branches were down for both value added and employment. Thanks to the "other services" branch of activity, investment rose steadily. The volume of cargo handled at the port of Brussels declined in 2009. Value added in this port remained steady. But employment contracted slightly. After the growth seen in 2008, investment was down by more than a quarter. This report provides a comprehensive account of these issues, giving details for each economic sector, although the comments are confined to the main changes that occurred in 2009.

Document type: Book

Liberia's infrastructure: A continental perspective

Scipedia content — Wed, 14 Oct 2020 14:53:41 +0200

Liberia's power generating capacity and national grid were completely demolished during 14 years of civil war. Piped water access fell from 15 percent of the population in 1986 to less than 3 percent in 2008. War also left the national road network in a state of severe disrepair. Since the return of peace, the port of Monrovia has resumed normal operations under private management, and progress has been made in securing donor finance for road reconstruction. Liberia has also successfully liberalized its mobile telephone markets, with low-priced access surging to 40 percent in 2009. Liberia's starkest challenge lies in funding a more cost-effective power sector. The country's generation capacity is barely one-tenth of the benchmark level of Africa's other low-income countries. The cost of generating power is exorbitant, and the power tariff is three times the regional average. Addressing Liberia's public infrastructure needs will require sustained expenditures of between $350 million and $600 million annually, mostly to fund power and transport. In the mid-2000s, with all sources of spending taken into account, Liberia spent around $90 million a year on infrastructure. An additional $17 million was lost to inefficiencies, such as underpricing of power. Because Liberia suffers an annual funding gap of between $250 million and $500 million per year, it will need a combination of increased finance, improved efficiency, and cost-reducing innovations to reach its infrastructure targets in a reasonable time. Without these, Liberians may have to wait for up to 40 years to achieve the targets.

Document type: Book

Introducing mobility in serious games enhancing situated and collaborative learning

Scipedia content — Wed, 14 Oct 2020 14:51:21 +0200

International audience; This paper explores the introduction of mobile technologies in a particular serious games subset called learning games. We focus on two main purposes where mobility turns out to be useful: situated learning and collaborative learning. The article outlines the opportunities and the remaining challenges for these learning situations. Some important issues are highlighted for immerging learners in real context. We also propose some scenarios to illustrate the benefits of mobile devices in classroom situations.

Document type: Part of book or chapter of book

Tool support for interactive prototyping of safety critical interactive applications

Scipedia content — Wed, 14 Oct 2020 14:49:10 +0200

The complete specification of interactive applications is now increasingly considered a requirement in the field of software for safety-critical systems due to their use as the main control interface for such systems. The reason for putting effort in the use and the deployment of formal description techniques lies in the fact that they are the only means for both modeling in a precise and unambiguous way all the components of an interactive application (presentation, dialogue, and functional core; Pfaff, 1985) and proposing techniques for reasoning about (and also verifying) the models (Palanque & Bastide, 1995). Formal description techniques are usually applied to early phases in the development process (requirements analysis and elicitation) and clearly show their limits when it comes to evaluation (testing). When the emphasis is on validation, iterative design processes (Hix & Hartson, 1993) are generally put forward with the support of prototyping as a critical tool (Rettig, 1994). However, if used in a nonstructured way and without links to the classical phases of the development process, results produced using such iterative processes are usually weak in terms of reliability. They can also be unacceptable when interfaces for safety-critical applications are concerned. If we consider interfaces such as the ones developed in the field of air traffic control (ATC), a new characteristic appears, which is the dynamics of interaction objects in terms of existence, reactivity, and interrelations (Jacob, 1999). In opposition to WIMP (windows, icons, menus, and pointing) interfaces, in which the interaction space is predetermined, these interfaces may include new interactors (for instance, graphical representations of planes) at any time during the use of the application (Beaudouin-Lafon, 2000). Even though this kind of problem is easily mastered by programming languages, it is hard to tackle in terms of modeling. This is why classical description techniques must be improved in order to be able to describe in a complete way highly interactive applications.

Document type: Part of book or chapter of book