Scipedia: Documents published in 2010

Determining the Relationships Among Airport Operational Performance Areas and Other Airport Characteristics

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

In this paper, a methodology is proposed to investigate pair-wise relationships between different types of airport operational performance variables. Having a better understanding of these relationships poses a fundamental contribution for investigating the pros and cons of air transportation systems in different countries. Considerable attention is paid to analyzing the most appropriate techniques in an effort to produce the most reliable results. Additionally, a method to display the results in a simple and clear way is also suggested to allow users to understand the results visually. The key variables obtained from the proposed methodology serve as building blocks for model development to answer a variety of air traffic questions, which allow policy makers to make decisions on allocating resources wisely.

A new single-error correction scheme based on self-diagnosis residue number arithmetic

Scipedia content — Thu, 28 Jan 2021 17:11:49 +0100

International audience; With the rapid size shrinking in electronic devices,radiation-induced soft-error has emerged as a major concern to the current circuit manufacturing. In this paper, we present a new error correction scheme based on the residue number arithmetic to cope with the single soft-error issue. The proposed technique called bidirectional redundant residue number system requires the redundant moduli to satisfy some constraints to achieve fast error correction. In this system, both the iterations for decoding the valid number and the error-correcting table that contains all combinations of erroneous digit, are not necessary. The detection and the diagnosis are simultaneously performed in plural parallel consistent-checking that has the capability of locating the corrupt digit. Finally, efficient pipeline architecture for the self-diagnosis decoder is detailed.

Dieselisation and road transport CO2 emissions: evidence from Europe

Scipedia content — Tue, 26 Jan 2021 18:19:20 +0100

emissões de dióxido de carbono dos transportes rodoviários são estudadas, através da análise de um painel de 14 países da União Europeia para a extensão temporal 1995-2007. A existência de correlação contemporânea é controlada, usando o estimador Panel Corrected Standard Errors. Contribui-se para a literatura, controlando para os efeitos dos novos carros de passageiros a diesel matriculados e da potência média desses veículos. O preço da gasolina e o rendimento reduzem as emissões de dióxido de carbono dos transportes rodoviários, enquanto a densidade populacional e a potência média dos novos carros de passageiros a diesel aumentam essas emissões. O debate sobre a “dieselização” é aprofundado, concluindo-se que a poupança nas emissões resultante da utilização de diesel tende a ser superada pelas crescentes distâncias percorridas.

Minimization of emissions in periodic supply vessel planning through speed optimization

Scipedia content — Tue, 26 Jan 2021 18:09:53 +0100

System designs for bulk and user-generated content delivery in the internet

Scipedia content — Tue, 26 Jan 2021 17:55:16 +0100

This thesis proposes and evaluates new system designs to support two emerging Internet workloads: (a) bulk content, such as downloads of large media and scientific libraries, and (b) user-generated content (UGC), such as photos and videos that users share online, typically on online social networks (OSNs). Bulk content accounts for a large and growing fraction of today's Internet traffic. Due to the high cost of bandwidth, delivering bulk content in the Internet is expensive. To reduce the cost of bulk transfers, I proposed traffic shaping and scheduling designs that exploit the delay-tolerant nature of bulk transfers to allow ISPs to deliver bulk content opportunistically. I evaluated my proposals through software prototypes and simulations driven by real-world traces from commercial and academic ISPs and found that they result in considerable reductions in transit costs or increased link utilization. The amount of user-generated content (UGC) that people share online has been rapidly growing in the past few years. Most users share UGC using online social networking websites (OSNs), which can impose arbitrary terms of use, privacy policies, and limitations on the content shared on their websites. To solve this problem, I evaluated the feasibility of a system that allows users to share UGC directly from the home, thus enabling them to regain control of the content that they share online. Using data from popular OSN websites and a testbed deployed in 10 households, I showed that current trends bode well for the delivery of personal UGC from users' homes. I also designed and deployed Stratus, a prototype system that uses home gateways to share UGC directly from the home. Schwerpunkt dieser Doktorarbeit ist der Entwurf und die Auswertung neuer Systeme zur Unterstützung von zwei entstehenden Internet-Workloads: (a) Bulk-Content, wie zum Beispiel die Übertragung von großen Mediendateien und wissenschaftlichen Datenbanken, und (b) nutzergenerierten Inhalten, wie zum Beispiel Fotos und Videos, die Benutzer üblicherweise in sozialen Netzwerken veröffentlichen. Bulk-Content macht einen großen und weiter zunehmenden Anteil im heutigen Internetverkehr aus. Wegen der hohen Bandbreitenkosten ist die Übertragung von Bulk-Content im Internet jedoch teuer. Um diese Kosten zu senken habe ich neue Scheduling- und Traffic-Shaping-Lösungen entwickelt, die die Verzögerungsresistenz des Bulk-Verkehrs ausnutzen und es ISPs ermöglichen, Bulk-Content opportunistisch zu übermitteln. Durch Software-Prototypen und Simulationen mit Daten aus dem gewerblichen und akademischen Internet habe ich meine Lösungen ausgewertet und herausgefunden, dass sich die Übertragungskosten dadurch erheblich senken lassen und die Ausnutzung der Netze verbessern lässt. Der Anteil an nutzergenerierten Inhalten (user-generated content, UGC), die im Internet veröffentlicht wird, hat in den letzen Jahren ebenfalls schnell zugenommen. Meistens wird UGC in sozialen Netzwerken (online social networks, OSN) veröffentlicht. Dadurch sind Benutzer den willkürlichen Nutzungsbedingungen, Datenschutzrichtlinien, und Einschränkungen des OSN-Providers unterworfen. Um dieses Problem zu lösen, habe ich die Machbarkeit eines Systems ausgewertet, anhand dessen Benutzer UGC direkt von zu Hause veröffentlichen und die Kontrolle über ihren UGC zurückgewinnen können. Meine Auswertung durch Daten aus zwei populären OSN-Websites und einem Feldversuch in 10 Haushalten deutet darauf hin, dass angesichts der Fortschritte in der Bandbreite der Zugangsnetze die Veröffentlichung von persönlichem UGC von zu Hause in der nahen Zukunft möglich sein könnte.Schließlich habe ich Stratus entworfen und entwickelt, ein System, das auf Home-Gateways basiert und mit dem Benutzer UGC direkt von zu Hause veröffentlichen können.

Procedural Expansion of Urban Environments

Scipedia content — Tue, 26 Jan 2021 17:49:08 +0100

Procedural generation of urban environments is a very difficult problem to solve. Most solutions use predefined production rules which lock them into only few different variations of the result. This works well when producing new urban environments but fails when it comes to the expansion of them. Most cities are too complex to model using an approach which utilises predefined rules. By using an example based approach instead, it is possible to expand any city and still have the new street network follow the layout of the original city, regardless of complexity. This paper describes a method of extracting the necessary information from the GIS database OpenStreetMap and expanding the cities using an example based approach presented by Aliaga et al. The paper will also show how blocks, parcels and buildings can be generated to fit within the urban environment.

Design and creation of different simulation architectures for hybrid and electric vehicles

Scipedia content — Tue, 26 Jan 2021 17:46:31 +0100

PFC del programa Erasmus EPS

Treball desenvolupat dins el marc del programa 'European Project Semester'.

Development of electric vehicle architectures requires complex analysis and innovative designs in order to produce a highly efficient mode of personal transportation acceptable to the target demographic. Using computer-aided modeling and simulation has been proven to decrease the development time of conventional vehicles while increasing overall success of the product design. Computer-aided automotive development also allows a fast response to the testing and inclusion of developing technologies in individual systems. Therefore, it follows to use this technique in the research and development of electric vehicles for consumer markets. This paper presents a system level model development and simulation for an electric vehicle using the Matlab-Simulink platform and its associated process. The current state of the art technologies for electric and plug-in hybrid electric vehicles are given to provide an introduction into the subject. Following, the project development is briefly described, detailing the specific goals for the project and the methods by which results were achieved. Next the paper discusses the analytical and simulation models for each key component as divided by the following systems: battery, charging, and traction. Model assembly and the development of a graphic user interface follows. Finally, the testing procedures for model validation, along with results, and future project works are provided.

Models and algorithms for the optimal design of bus routes in public transportation systems

Scipedia content — Tue, 26 Jan 2021 17:45:32 +0100

In this thesis we study models and algorithms for the optimal design of bus routes in urban public transportation systems. The problem known as TNDP (Transit Network Design Problem) consists in determining the number and itinerary of public transportation lines and their corresponding frequencies, in terms of a given infrastructure of streets and stops. The solutions should satisfy a given origin-destination demand and should take into account the interests of users and operators and a given set of physical, policy and budgetary constraints. We propose an explicit mixed integer linear programming formulation which incorporates the waiting time and the existence of multiple lines in the behavior of the passengers.Then, we discuss the impact in the structure of the model of adding transfer, infrastructure and bus capacity constraints. We apply the model (using a standard solver) to very small test cases as well as to a real one, related to a small-sized city comprising 13 bus lines. In order to deal with cases of larger sizes, we propose a greedy constructive algorithm that produces a set of routes that are convenient for both users and operators, taking into account constraints related to transfers. By using a real test case, we show that the proposed algorithm improves results from the state of the art. As a further extension, we represent the existence of the conflicting objectives of users and operators using a multi-objective combinatorial optimization model for the TNDP. This new model is solved by a metaheuristic that exploits the multi-objective nature of the problem in order to solve it eficiently. By using a benchmark test case and a real one, we show that the proposed algorithm improves results from the state of the art and produces solutions with characteristics comparable to the real one. Objective values of both constructive and metaheuristic algorithms are compared with values corresponding to reference solutions; for the first one we compare against optimal solutions obtained with the mathematical formulation, while for the second one we compare with the solution operating the public transportation system of the city corresponding to the real test case. Finally we discuss the relationships between the diferent contributions of this thesis and we comment several issues related to the application of the proposed methodologies to real cases. We also give some opinions and recommendations concerning future developments in this research field. En esta tesis se estudian modelos y algoritmos para el diseño óptimo de recorridos de buses en sistemas de transporte público urbano colectivo. El problema conocido como TNDP (Transit Network Design Problem) consiste en determinar el número y el itinerario de líneas de transporte público y sus correspondientes frecuencias, en términos de una infraestructura dada de calles y paradas. Las soluciones deben satisfacer una demanda origen-destino dada y deben tener en cuenta los intereses de los usuarios y de los operadores y un conjunto dado de restricciones físicas, políticas y de presupuesto. Se propone una formulación explícita de programación lineal entera mixta, que incorpora el tiempo de espera y la existencia de múltiples líneas en el comportamiento de los pasajeros. Seguidamente se discute el impacto en la estructura del modelo, al agregar restricciones de transbordos y de capacidad de la infraestructura y de los buses. El modelo se aplica (usando un solver estándar) a casos de prueba muy pequeños, así como a uno real relativo a una ciudad pequeña que consta de 13 líneas de buses. Con el propósito de atacar casos de mayor tamaño, se propone un algoritmo constructivo ávido que produce un conjunto de recorridos que son convenientes tanto para los usuarios como para los operadores, teniendo en cuenta restricciones de transbordos. Utilizando un caso de prueba real, se muestra que el algoritmo propuesto mejora resultados del estado del arte. Como una extensión del algoritmo constructivo, se representa la existencia de los objetivos en conflicto de usuarios y operadores usando un modelo de optimización combinatoria multi-objetivo para el TNDP. Este nuevo modelo se resuelve con una metaheurística que explota la naturaleza multi-objetivo del problema para resolverlo eficientemente. Utilizando un caso de prueba de referencia existente en la literatura y uno real, se muestra que el algoritmo propuesto mejora resultados del estado del arte y produce soluciones de características comparables a las del sistema real. Los valores objetivo del algoritmo constructivo y de la metaheurística se comparan con valores correspondientes a soluciones de referencia; en el primer caso se compara contra soluciones óptimas obtenidas con la formulación matemática, mientras que para el segundo se compara contra la solución que opera el sistema de transporte público de la ciudad correspondiente al caso de prueba real. Finalmente se discuten las relaciones entre las diferentes contribuciones de esta tesis y se comentan varias cuestiones relacionadas a la aplicación de las metodologías propuestas a casos reales. También se formulan algunas opiniones y recomendaciones en relación a futuros desarrollos de éste tópico de investigación.

Potentials of hybrid and electric cars to reduce energy consumption and greenhouse gas emissions in passenger car transport : techno-economic assessment and model-based scenarios

Scipedia content — Tue, 26 Jan 2021 17:38:20 +0100

von Maximilian Kloess Zsfassung in dt. Sprache Wien, Techn. Univ., Diss., 2011

Investigation of the parameters of the public urban bus movement and the passengers flows

Scipedia content — Tue, 26 Jan 2021 17:30:51 +0100

For long time, most of the big cities have serious problems of congestion in the streets because of the high use of private vehicles, which means also more pollution and traffic accidents, among others. Therefore, for over many years ago and up to nowadays has been investigating in order to improve the quality and service of the public transportation and thus make it more attractive for the people. Since the people spend very much time going to work, university, etc., a very important aspect for the traveller is his travel time. This includes the time going to and from the bus stop, waiting and travel time. These times may be optimized and reduced with and effective route and with a good commercial speed of the bus as well. This project is focused on investigating some aspects of transport engineering of the urban bus route number 43 of the city of Kaunas, Lithuania. In order to do it, the study is performed for several time periods in a weekday and on Saturday. The research intends to analyze four factors: the speed of the vehicle along the route, the passenger’s flow, the passenger travel distance and the passenger travel time. In the experimental research it is obtained data of passengers flow throughout the route; and, in order to get data of bus speed we have a GPS which is able to store files at high frequency. The results indicate that the vehicle speed is not affected by the load; however it might be significant when comparing average bus speeds of the streets. The calculations give an average travel distance on the vehicle equal to 4,79 km and an average travel time - including walking and waiting time - nearly 24 minutes. About passengers’ flows, they are localized in a small time interval during the morning peak time. However, in the afternoon the passengers come back home during more prolonged time and often without peaks of flow.

Outgoing

Rotterdam Kuralları Ve Türkiye Açısından Değerlendirilmesi

Scipedia content — Tue, 26 Jan 2021 17:23:38 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011

Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2011

Bu çalışmada, deniz yolu ile eşya taşımacılığını düzenleyen uluslararası sözleşmeler ele alınarak Rotterdam Kuralları’nın getirmiş olduğu yeni hükümler Lahey-Visby Kuralları ve Hamburg Kuralları ile karşılaştırmalı olarak ortaya konmaya çalışılmıştır. Genel kanı olarak Lahey-Visby Kuralları daha çok taşıyanlar lehine, Hamburg Kuralları ise daha çok taşıtanlar lehine kurallar içermektedir. Mevcut konvansiyonların yarattığı uygulamadaki farklılıklara son vererek deniz taşımacılığına uluslararası yeknesak kurallar getirmeyi ve günümüz modern taşımacılık sistemlerinin ihtiyaçlarını karşılamayı amaçlayan Rotterdam Kuralları’nın taşıyan ve taşıtan arasında sorumlulukların paylaşımı konusunda daha dengeli olduğu ve bu açıdan bakıldığında Lahey-Visby Kuralları ve Hamburg Kuralları’nın ortasında yer aldığı kanaati oluşmuştur. Uluslararası arenada taşıma ve taşıtma kapasitesi incelendiğinde taşıtan bir ülke olarak karşımıza çıkan Türkiye’de yürürlükte olan düzenlemenin taşıyanlar lehine hükümler içermesi ve Türkiye’nin ticaret yaptığı ülkeler arasında Rotterdam Kuralları’nı imzalamış ülkelerin bulunması sebebiyle konvansiyona taraf olmasa bile yürürlüğe girdiği anda uygulama alanına dahil olacağı gözönüne alınarak Türkiye’nin Rotterdam Kuralları’nı desteklemesi gerektiği sonucuna varılmıştır.

A comparative study of the provisions of the Rotterdam Rules, Hague-Visby and Hamburg Rules, the international conventions to regulate carriage of goods by sea, is hereby realized. It is generally accepted that the Hague-Visby Rules were in favor of the carriers while the Hamburg Rules in favor of ship owners. Meanwhile, the Rotterdam Rules are more balanced ending the differences in implementation and aiming to bring international uniform rules to sea carriage while also meeting the needs of modern carriage systems, and have found a middle course between the Hague-Visby and Hamburg Rules. Considering Turkey s capacity as a shipper despite the pro-carrier provisions of the regulation in effect, and Turkey s trade relationship with the undersigning countries, Turkey should support the Rotterdam Rules although the country is not a party to the convention, it will be included in the implementation area once effective.

Yüksek Lisans

M.Sc.

Traffic engineering multi-layer optimization for wireless mesh network transmission a campus network routing protocol transmission performance inhancement

Scipedia content — Tue, 26 Jan 2021 17:17:24 +0100

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The wireless mesh network is a potential network for the future due to its excellent inherent characteristic for dynamic self-healing, self-configuration and self-organization. It also has the advantage of easy interoperability networking and the ability to form multi-linked ad-hoc networks. It has a decentralized topology, is cheap and highly scalable. Furthermore, its ease in deployment and easy maintenance are other inherent networking qualities. These aforementioned qualities of the wireless mesh network bring advantages to transmission capability of heterogeneous networks. However, transmissions in wireless mesh network create comparative performance based challenges such as congestion, load-balancing, scalability over increasing networks and coverage capacity. Consequently, these challenges and problems in the routing and switching of packets in the wireless mesh network routing protocols led to a proposal on the resolution of these failures with a combination algorithm and a management based security for the network and its transmitted packets. There are equally contentious services like reliability of the network and quality of service for real-time multimedia traffic flows with other challenges such as path computation and selection in the wireless mesh network. This thesis is therefore a cumulative proposal to the resolution of the outlined challenges and open research areas posed by using wireless mesh network routing protocol. It advances the resolution of these challenges in the mesh environment using a hybrid optimization – traffic engineering, to increase the effectiveness and the reliability of the network. It also proffers a cumulative resolution of the diverse contributions on wireless mesh network routing protocol and transmission. Adaptation and optimization are carried out on the wireless mesh network designed network using traffic engineering mechanism and technique. The research examines the patterns of mesh packet transmission and evaluates the challenges and failures in the mesh network packet transmission. It develops a solution based algorithm for resolutions and proposes the traffic engineering based solution.. These resultant performances and analysis are usually tested and compared over wireless mesh IEEE802.11n or other older proposed documented solution. This thesis used a carefully designed campus mesh network to show a comparative evaluation of an optimal performance of the mesh nodes and routers over a normal IEE802.11n based wireless domain network to show differentiation by optimization using the created algorithms. Furthermore, the indexes of performance being the metric are used to measure the utility and the reliability, including capacity and throughput at the destination during traffic engineered transmission. In addition, the security of these transmitted data and packets are optimized under a traffic engineered technique. Finally, this thesis offers an understanding to the security contribution using traffic engineering resolution to create a management algorithm for processing and computation of the wireless mesh networks security needs. The results of this thesis confirmed, completed and extended the existing predictions with real measurement.

Technological Construction as Identity Formation: the High Speed Rail, Hybrid Culture and Engineering/Political Subjectivity in Taiwan

Scipedia content — Tue, 26 Jan 2021 17:07:00 +0100

This project examines the construction of the Taiwan high-speed rail (THSR; 台灣高鐵) technology as a vehicle of Taiwanese identity formation. The THSR project is a product of a hybridization of design from Japan and Europe. The Japanese and Europeans transferred their HSR technology to Taiwan, but Taiwanese policy actors and engineers localized and assimilated it to their politics, society and history. They reconstructed the meanings of HSR technology in an indigenized (Ben-Tu-Hua; 本土化) and democratic way. In addition to focusing on the THSR's technological content and engineering practice, this dissertation explores how Taiwan identity formation has shaped technology and vice versa. The identity formation and technological construction in Taiwan tell one techno-political story. Since the 1960s and 1970s, Taiwanese engineers were forced by international politics to cannibalize technological projects, but later they began to localize and hybridize different foreign engineering skills and knowledge. This growing engineering culture of hybridity generated impacts on the development of Taiwan's identity politics. Some critical political leaders exploited their engineers' capability to hybridize to introduce international power into Taiwan. This power then was used to either strengthen the Taiwanese population's Chinese identity or to build their Taiwanese identity. Both politics and technology offered each other restrains and opportunities. This project offers an approach from science and technology studies to understand postcolonial technopolitics. The engineering practice of hybridity in Taiwan has become a locally transformed knowledge to reframe and negotiate with the more advanced technologies from the West and Japan, even though it was a contingent outcome of earlier international politics. In addition to technological non-dependence, this engineering culture of hybridity has given the Taiwanese an independent political vision not only against China but the West and Japan. However, Taiwan paid significant prices to acquire technological non-dependence and international independence. In addition to extra wasted money and time, some over design was often seen in their public projects. Large technological projects also often draw political patronage. Moreover, techno-political survival alone might not be enough to represent postcolonial resistance. Ph. D.

Ground holding optimisation and air schedule recovery /

Scipedia content — Tue, 26 Jan 2021 17:04:40 +0100

Thesis (PhDMathematics)--University of South Australia, 2011. Includes bibliographic references. Ground holding is one of the safest and most effective management strategies available to airlines and airspace regulators when their carefully designed schedules are disrupted. When the already limited capacity of airports and airspace is restricted, most commonly by adverse weather, flights are delayed by keeping them on the ground at their point of departure. Flight delays propagate through the schedule because delayed flights may have connections to many successors. Usually disruptions can be anticipated, and it is necessary for services to be rescheduled as quickly as possible.

The European Concept of Green Corridors in Sustainable Transport Systems : Case of East-West Transport Corridor in the Baltic Sea Region

Scipedia content — Tue, 26 Jan 2021 16:55:14 +0100

new European concept - Green Corridors - has been introduced to the EU member states defining them as long-distance freight transport corridors where advanced technology and co-modality are used to achieve energy efficiency and reduce environmental impact. Key objectives of the thesis are the development of the European concept of Green Corridor regarding the theory of sustainable transport and EU transport policy, the implementation level of the concept within the East-West Transport Corridor and the relation of a’ greener’ East-West corridor to sustainable transport solutions in the Baltic Sea Region as well as towards more sustainable transport system in the EU. The analysis of the sustainable transport systems and the concept of green transport corridors have been applied to the East-West Transport Corridor in the BSR through the trans-national cooperation project EWTC II, as a case study with a review of EU documents and academic literature as well as research into the documentation of the project.

Congestion avoidance and break scheduling within vehicle routing

Scipedia content — Tue, 26 Jan 2021 16:32:00 +0100

Vehicle routing is a complex daily task for businesses such as logistic service providers and distribution firms. Planners have to assign many orders to many vehicles and, for each vehicle, assign a delivery sequence. The objective is to minimize total transport costs. These costs typically include the number of vehicles used and the total travel distance or time. Two general timing restrictions make vehicle routing particularly difficult: traffic congestion and driving hours regulations. As a result of traffic congestion, travel times depend on the time of departure. Therefore, vehicle routing also involves the subtask of optimizing each vehicle’s departure times (both from the depot and from the customers). Driving hours regulations - which pose restrictions on driving and working times (between breaks) - have to be taken into account, making departure time optimization particularly difficult. In this research, we study the Vehicle Routing Problem under time-dependent travel times and driving hours regulations. We propose a generic solution method for Vehicle Routing Problems that can handle various restrictions, such as vehicle capacities and time windows. Furthermore, we demonstrate that this method performs very well on problems which include driving hours regulations. Test results on Vehicle Routing Problems with traffic congestion are also very promising. Most delays caused by traffic congestion can be avoided by considering them when developing vehicle route plans. This is done by avoiding predictably busy areas during problematic hours. The solution methods proposed in this thesis are not limited to the problems they were initially designed for. We illustrate how they can be used in other studies, such as policy making, by analyzing vehicle routing from a distributed decision making perspective. In conclusion, there are various applications of the solution methods proposed in this thesis and they may allow for substantial improvements in practice.

Elektrikli Minibüs Dizayn Ve Üretimi

Scipedia content — Tue, 26 Jan 2021 16:27:08 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011

Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2011

İstanbul Teknik Universitesi kampüsü içinde ring aracı olarak kullanılması amaçlanan full elektrikli minibus aracın dizayn ve yapım asamasındaki basamakları bu yüksek lisans tezinde aktarılmıstır. Batarya ve elektrik motoru ile güç aktarımı saglanan elektrikli minibüste, aktarma organı olarak sanzıman kullanılmamıs, sadece difransiyel aradaki mekanik güç aktarımını saglamıstır. Elektrik Motoru, Batarya ve güç yönetim sistemlerinin secim kriterleri detayları ile sunulmustur. Önemli dizayn parametreleri yapısal diagramlar ile aktarılmıstır. Bunun yanı sıra, arac kontrolu ve arac kontrolunu saglayan haberlesme protokolunun uygulamasal olarak araca uygulanısı anlatılmıstır. Enerji tüketimi, maliyet hesaplamaları ve seçilen araç ekipmanlarının performansları detaylı olarak incelenmistir. Araç üstünde kosturulan kontrol algoritması güvenlik ve verimlilik açısından kampüs içinde yapılan testler ile gelistirilmistir. Anahtar Kelimeler: Elektrikli Minibüs, Araç Kontrolü, Haberlesme Protokolü.

Electric minibus is planned as a shuttle on Istanbul Technical University, which is presented in this Master of Science thesis and its stages, includes not only scientific but also application stages. This electric minibus is powered by an electric motor and there is no gearbox as power train equipment. The selection steps of electric motor, battery and power electronic units are explained in details. The electric vehicle design parameters are shown with the structural diagrams. Moreover, vehicle control specifications including communication protocol, motor controller and vehicle main controller are given. Energy consumption and performance of selected components are evaluated. Following, the first prototype electric minibus is constructed and tested on university campus. Designed Control process is tested on the vehicle to improve safety and efficiency. Keywords: electric minibus, vehicle control, vehicle efficiency, communication protocol

Yüksek Lisans

M.Sc.

System for determination of separation minima

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

Tese de mestrado em Engenharia Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011 No paradigma actual da Navegação Aérea, em que o aumento da densidade do tráfego aéreo é acompanhado pelo crescimento em número e complexidade das infraestruturas de vigilância do espaço aéreo, torna-se imperativo optimizar os recursos de forma a continuar a prestar um serviço de Controlo de Tráfego Aéreo de excelência. Neste contexto surge o conceito de Separação Mínima: a distância mínima a que duas aeronaves se podem encontrar uma da outra, independentemente das suas direcções, sem que a sua segurança ou a segurança de aeronaves terceiras sejam comprometidas. Vários factores são considerados na decisão da Separação Mínima aplicável numa dada situação. Um deles prende-se com a confiabilidade das infra-estruturas de vigilância. É nesse intuito que surge este projecto, que tem como objectivo fornecer aos grupos de estudo de Separação Mínima uma ferramenta de análise da infra-estrutura de vigilância que lhes permita avaliar cada componente da infra-estrutura independentemente e como um todo, mediante certas características com alta relevância para a sua confiabilidade, de acordo com a EUROCONTROL. Em Portugal, o estudo da confiabilidade da infra-estrutura de vigilância está a cargo da secção de Sistemas e Software/Qualidade (SISQUA) do Departamento de Sistemas e Tecnologias de Informação (DSTI) da NAV Portugal. No âmbito desta equipa, foi-me confiada a tarefa, durante estes onze meses, de desenvolver uma aplicação que automatizasse grande parte do estudo sobre confiabilidade das infraestruturas de vigilância, baseada num protótipo desenvolvido em Microsoft Excel no início deste milénio pela coordenadora do SISQUA, a Engenheira Paula Santos. Este projecto, de uma complexidade considerável considerando toda a aprendizagem de novas tecnologias e metodologias e de uma nova área de negócio, envolveu várias etapas, que são descritas neste Relatório de Projecto. De entre as mais complexas, é de destacar a fase da Análise, na qual toda a fase de aprendizagem se inseriu, e em especial o estudo do “Gap”. O estudo do “Gap” recebeu, sem dúvida, muita ênfase ao longo deste projecto, tendo estado na origem de atrasos significativos e consideráveis dores de cabeça; consistiu no estudo da integração e mapeamento de dados entre a versão 7 do software SASS-C (produzido pela EUROCONTROL para estudo da infra-estrutura de vigilância dos estados-membros que dela fazem parte) e a solução a ser desenvolvida. Este projecto seguiu a metodologia interna da NAV Portugal para desenvolvimento de software, definida como POP-20, tal como as boas práticas aprendidas por mim ao longo de cinco anos de estudo académico e de várias experiências profissionais e de investigação académica. Esta metodologia, implementada na NAV Portugal pelo SISQUA, define um processo de desenvolvimento de software iterativo baseado na aproximação de Desenvolvimento Dirigido por Testes (Test-Driven Development), descrevendo para cada fase do processo de desenvolvimento uma etapa da fase de testes (que ocorre em paralelo) com o intuito de a testar. O POP-20 prevê a elaboração de extensa documentação; toda a documentação aplicável a este projecto foi produzida, revista, e aprovada. Foi tomada a decisão de recorrer à framework ASD (Air Situation Display) no contexto do desenvolvimento do projecto. Esta framework, desenvolvida integralmente pela NAV Portugal, expõe um interface gráfico baseado num sistema de plugins orientado para a representação visual de informação sobre o espaço aéreo, nomeadamente trajectórias de aviões em tempo real e planos de voo. No contexto deste projecto, foram desenvolvidos plugins com a lógica necessária, e esses plugins foram integrados na framework ASD para obtenção do resultado final. Aquando da conclusão deste projecto ainda se encontravam pendentes várias validações que não puderam ser executadas devido a inconsistências gravíssimas encontradas na base de dados do SASS-C v7, que tornaram impossíveis as execuções de Testes de Aceitação. No entanto, não deixam de ser evidentes os contributos prestados pelo trabalho desenvolvido ao longo dos onze meses transactos. A NAV Portugal passou a dispor de uma ferramenta extensível e de capacidade escalável que servirá, sem dúvida, para analisar a sua infra-estrutura de vigilância durante muitos anos. Poderá também vir a ser integrada noutras áreas de interesse da NAV Portugal (como Santa Maria) ou de outros prestadores de serviço de Controlo de Tráfego Aéreo, devido à extensa documentação que foi produzida e à modularização da implementação. Por último, e com impactos imediatos, forneceu à comunidade europeia de estudo de infraestruturas de vigilância elações extensivas sobre a mais recente versão do software utilizado no seio desta comunidade para análise das infra-estruturas – o SASS-C. Tenho esperança de que venha também a exercer algum impacto sobre a EUROCONTROL, para que seja dada mais atenção a um software cuja versão mais recente apresenta enormes potencialidades, até agora não realizadas devido a inconsistências e falhas que a tornam inutilizável. In the current paradigm of Air Navigation, in which the increase in airspace density is accompanies by an increase in number and complexity of available Surveillance infrastructures, it becomes imperative to optimize all resources in order to continue to provide excellent services in Air Traffic Control. For this to happen, the separation between aircraft must be kept at a minimum, whilst still abiding by the worldwide security requirements that make us all feel safer on board an airplane than driving our cars. In this context, NAV Portugal’s Surveillance infrastructure analyst Paula Santos has initiated this project in the turn of the millennium by creating a prototype using Microsoft Excel to study the reliability and confidence that available surveillance infrastructures provide. The acclaim her approach received from European peers created the demand for an extensible, scalable solution build using modern technologies which can facilitate the accommodation of changes in the infrastructures, something the prototype did not. The System for Determination of Separation Minima presents the Separation Minima study community with precisely that. It integrates with SASS-C v7’s – EUROCONTROL’s software for evaluation of surveillance data recordings – to present users with valuable graphical data – and more – about each component of the Surveillance System, in separate or in cooperation. Its robust, modular build, allied with the extensive documentation produced during all the stages of software development, will facilitate the introduction of new features by future developers, as well as its adaptation to new types of Surveillance infrastructures and technologies. While at this time the solution has not been fully validated – due to severe conditionings imposed by the discrepancy between SASS-C v7’s data and its predecessor’s, SASS-C v6’s – it is our sincere belief that in the very near future, in cooperation with EUROCONTROL, the System for Determination of Separation Minima will be a vital decision-support tool for the Separation Minima study group in Portugal – and perhaps abroad.

La demanda de gasolinas en México: Efectos y alternativas ante el cambio climático

Scipedia content — Tue, 26 Jan 2021 16:16:38 +0100

El autotransporte es de los sectores más contaminantes en México, generando alrededor de 17% del total de emisiones de CO2. El consumo de gasolina y diesel son la principal fuente de estas emisiones. Este artículo analiza empíricamente la demanda de gasolinas del sector automotor en México durante el periodo 1960-2008. Las estimaciones de las elasticidades de largo y corto plazos del precio e ingreso fueron: -0.285, -0.041, 1.004 y 0.721, lo que implica que la demanda de gasolinas es sensible a la trayectoria del ingreso e inelástica a los precios. Por tanto, un crecimiento económico continuo, sin una adecuada política de precios, generará un aumento en el consumo de gasolinas. Esta situación puede ser más grave al considerar los efectos del cambio climático suponiendo una demanda relativamente constante. Bajo estas circunstancias es necesario implantar diversas políticas públicas simultáneamente para frenar las consecuencias del consumo de gasolinas sobre el cambio climático. The transportation sector is one of the most polluting sectors in Mexico, generating around 17% of total CO2 emissions. Moreover, the consumption of gasoline and diesel are the main source of these emissions. This document empirically analyses the fuel demand in the transportation sector of Mexico over the period 1960-2008. The results show that the long -and short- run price and income elasticities in fuel consumption are: -0.285, -0.041, 1.004 and 0.721. This implies that fuel demand is sensitive to the trajectory of income and is inelastic to prices. Therefore, a continuous economic growth without a suitable price policy will generate an increase in gasoline consumption. This situation could be worst if we take into consideration the effects on climate change. Under these circumstances it is necessary to implement simultaneously a variety of public policies to control the impact of fuel consumption on climate change.

Document type: Article

Modified particle swarm optimization for day-ahead distributed energy resources scheduling including vehicle-to-grid

Scipedia content — Tue, 26 Jan 2021 15:47:00 +0100

Mestrado em Engenharia Electrotécnica – Sistemas Eléctricos de Energia This thesis proposes a modified Particle Swarm Optimization (PSO) approach for the day-ahead scheduling of Distributed Energy Resources (DER) in smart grids, considering Electric Vehicles (EVs) with gridable capability (vehicle-to-grid). The proposed methodology introduces several changes in traditional PSO meta-heuristic to solve effectively the scheduling problem of DER with EVs. This thesis proposes an intelligent mechanism for adjusting the velocity limits of the swarm to alleviate violations of problem constraints and to improve the quality of the solution, namely the value of the objective function. In addition, a hybridization of PSO method is used, which combines this meta-heuristic with an exact method, a full ac power flow in order to validate network constraints of the solutions explored by the swarm. This thesis proposes a trip reduce demand response program for EVs users. A datamining based methodology is used to support the network operator in the definition of this program and to estimate how much demand response is adequate for a certain operation condition. The case studies included in the thesis aim to demonstrate the effectiveness of the modified PSO approach to the problem of DER scheduling considering EVs. An application named EV Scenario Simulator (EVeSSi) has been developed. EVeSSi allows creating scenarios considering EVs in distribution networks. A case study comparison of the modified PSO with an accurate mixed integer non-linear programming is presented. Furthermore, it is also compared with other variants of PSO, and the traditional PSO. Addionatly, different methods of EV battery management, namely uncontrolled charging, smart charging and vehicle-to-grid, are compared. Finally, a test case is presented to illustrate the use of the proposed demand response program for EVs and the data-mining methodology applied to a large database of operation scenarios. Esta tese apresenta uma aplicação modificada e adaptada da meta-heurística Particle Swarm Optimization (PSO) para o escalonamento de recursos energéticos em redes de distribuição inteligentes vulgo smart grids, considerando a utilização de veículos eléctricos. Este conceito em que os veiculos podem carregar e descarregar energia para a rede eléctrica é denominado na giria anglo-saxónica por vehicle-to-grid. Esta tese apresenta várias modificações na meta-heuristica PSO original para resolver mais eficazmente o problema do escalonamento de recursos energéticos com veículos eléctricos. Realça-se nesta tese a prosposta de um mecanismo inteligente para o ajustamento do limite das velocidades do swarm com vista a aliviar violações de restrições do problema e a melhorar a qualidade da solução, isto é, o valor da função objectivo. Adicionalmente, refere-se a hibridização desta meta-heurística com um método exacto, nomeadamente um trânsito de potências com o objectivo de verificar o cumprimento das restrições da rede eléctrica das soluções exploradas pelo swarm. Um programa de demand response para veículos eléctricos é apresentado na tese. Além disso, uma metodologia baseada em técnicas de data-mining é proposta para suportar as decisões do operator de sistema na definição e na estimativa do uso desse programa. Os casos de estudo incluídos nesta tese pretendem demonstrar a eficácia do PSO modificado no problema do escalonamento de recursos energéticos considerando os veículos eléctricos. Uma aplicação com a designação de EVeSSi foi desenvolvida e apresentada nesta tese para criar cenários de penetração de veículos eléctricos e simular os movimentos dos veículos ao longo dos nós das redes de distribuição. Um caso de estudo de comparação com um método exacto de programação não linear inteira mista é apresentado. Além disso, a aplicação proposta é comparada com outras variantes do PSO, incluindo a versão original. São ainda incluídos casos de estudo que abordam diferentes metodologias de interação do veículo com a rede, nomeadamente uncontrolled charging, smart charging e vehicle-to-grid. Por fim, é apresentado um caso de estudo com o programa de demand response e a metodologia de data-mining.

How can Electric Vehiclesbecome the Dominant Design?

Scipedia content — Tue, 26 Jan 2021 15:46:04 +0100

Due to technological developments and raising environmental concerns, vehicle industry is ina transformation process. Current dominant design in the industry is the internal combustionengine vehicle but there are already different alternative vehicles like electric vehicles (EV),hybrids, and vehicles running on ethanol or hydrogen. These alternatives started to expandand they are competing to have a strong position in the market. The question is whichtechnology (EV, hybrid, ethanol) will have an important position in the future. This studyfocuses on the progress of electric vehicles towards being the dominant design in the vehicleindustry and aims to give advices and suggestions to electric car manufacturers what theyshould develop and concentrate on in the future. To achieve this aim, interviews with Renaultand Stockholm Municipality is conducted and analyzed in detail. Many manufacturers areinterested in EV technology and started to invest in the technology to have a strong position inthe future. Although EVs are ready to expand, there are still some obstacles in their way.Some of these problems can be solved in a short term, while others, mostly technology relatedimprovements still require time.

Learning for safety in health care and air traffic control

Scipedia content — Tue, 26 Jan 2021 15:42:56 +0100

Introduction"br /" "br /" Risk management in enterprises, organisations and companies has had a long and complicated history. "br /" During the eighties, and at least during the beginning of the nineties, the notion concerning risk management was that if an accident happened in an otherwise perfect system it was due to the human operator in some way being the cause of the error. The cause for the accidents was described in terms of “negligence”, “lack of competence” and such similar statements."br /" "br /" Gradually, during the late nineties, the risk management paradigm shifted. "br /" James Reason, a psychologist, made a tremendous impact with his book Human error, published in 1990."br /" He introduced the term latent failures (or latent conditions). These, he said, are “resident pathogens”, built into the system. They are latent since the system can live with these pathogens for months and even years, and perform adequately, until something happens, which hampers the “immune system of the system”."br /" Reason states that the human operator goes to work everyday with the intention of doing a good job. The human operator has no wish “to screw up things”. When accidents happen, and operators make mistakes, it is therefore not a deliberate action. The causes should be sought in design flaws in the system. "br /" "br /" In this thesis we are dealing with high-risk systems, though not high-risk technologies. We are studying acute somatic health care, air traffic control, pharmacy and cancer treatment. We will explore different ways for an organisation to receive feedback from safety related occurrences, in order to improve safety."br /" "br /" The aim with this thesis will be to explore methods for obtaining safety feedback in the above mentioned domains. "br /" Four different approaches will be attempted:"br /" "br /" • Retrospective learning from accidents (paper I)"br /" • Proactive learning using an external agent (paper II)"br /" • Operator centred learning (paper III)"br /" • User centred proactive learning (paper IV) "br /" "br /" Methods and material"br /" "br /" Methods"br /" "br /" In paper I we used MTO (Man-Technique-Organisation) analysis as described by the nuclear power operators in Sweden, with a certain adaptation for health care. "br /" "br /" Paper II was inspired on the work with paper I. During the numerous interviews with doctors and nurses a quite common reaction was: “Why did we not think of these risks before? It is so obvious!”"br /" Another concern was the limited value of retrospective investigations when it comes to improving safety. "br /" This started us on designing a method for proactive risk analysis. Several methods were already described for this, but they were mainly tuned to technical systems with more or less tight coupling, assuming a high degree of linearity (as for instance the Failure Mode and Effect Analysis, FMEA). We felt these methods did not fit the way in which our studied organisations functioned. The result was the DEB (Disturbance- Effect-Barrier) analysis used in paper II. The identified system weaknesses by using this method was compared to system weaknesses extracted from the analysis (done by headquarter analysts) of 15 loss of separation incidents at the unit."br /" "br /" When working with this it became obvious that one category of incidents, i.e. the loss of separation incidents (AIRPROX) , was only the tip of the iceberg. Each day there were a number of near misses that did not result in loss of separation, and therefore not used for safety feedback. Talking to the controllers also revealed a hidden knowledge on questionable procedures that might constitute risks. Thus the idea was fairly simple: Why not let the controllers do the job of analysing safety occurrences? This led to the design of a method for operator-centred learning, i.e. paper III. The method included a brief to the controllers for 1½ days on system thinking."br /" "br /" The starting point for paper IV was particularly tragic. I investigated a case where an eight-year-old girl with cancer was killed by mistake. She was administered the total dose of cytotoxic agents each day for three days, i.e. a 300% overdose. We used the DEB analysis again, for a proactive risk analysis of the process of treating patients with cytotoxic drugs, but this time using a formalised user group. "br /" "br /" Material"br /" The material for paper I was a consecutive series of eight reports to the National Board of Health and Welfare, from acute somatic health care."br /" "br /" The material for paper II was a DEB analysis performed for the processes at the Malmoe air traffic control unit in Sweden."br /" "br /" In paper III a trial was performed for half a year with extended reporting of learning occurrences. In this way an additional 45 occurrences were reported which otherwise would not have been documented and analysed."br /" "br /" In paper IV the DEB analysis were performed at one ward unit at the department of oncology at the Lund University hospital, taking into consideration interface problems between the ward unit and the hospital pharmacy (which prepared the cytotoxic infusions)."br /" "br /" Results"br /" In paper I we could demonstrate that the notion of latent conditions was fruitful for analysing and learning from medical accidents. We identified a number of system weaknesses in seven out of eight cases, providing a good potential for improving safety."br /" "br /" In paper II we identified a number of risks (latent conditions) in the air traffic control system. We compared the identified system weaknesses with 15 loss of separation cases, investigated by the regulator. We identified all system weaknesses from 14 out of 15 as loss of separation analyses. "br /" In paper III we could demonstrate that the operators indeed were able to analyse “learning occurrences”, and to identify preventive actions, one of these being training on the aircraft flight management system for controllers. Also, they could show that quite a few number of “unexpected flight behaviours” actually were actually partly caused by air traffic control actions."br /" "br /" In paper IV we refined the DEB analysis by using a formalised reference group of staff from the very beginning.. The analysis disclosed a number of system weaknesses, which were presented for the staff. The disclosed risks were accepted as valid, and quite a few of our recommendations were implemented during the next couple of years"br /" "br /" Discussion"br /" We discuss our methods in relation to current research, particularly we discuss MTO analysis in relation to root cause analysis, and DEB analysis in relation to FMEA. We are critical to both. We find that both methods could benefit from using the notion of latent conditions, and even applying the concept and vocabulary from the ISO 9000 quality management standard when describing risks."br /" "br /" We discuss the learning potential of retrospective vs. proactive analysis and are in favour of proactive methods."br /" "br /" We introduce complexity theory and relate this to our results. Our conclusion is that the operator-centred approach (paper III) seems to be the most effective way of influencing a complex system in a desirable manner, concerning self-organising and emergent properties. Hantering av risker i företag och organisationer har haft en lång och komplicerad historia. "br /" På åttiotalet, och i början av nittiotalet, var uppfattningen att om en olycka inträffade i en organisation, som påstods vara nära nog perfekt, måste det bero på ”den mänskliga faktorn”, dvs. att en eller flera medarbetare inte gjorde som de borde ha gjort. Orsakerna till olyckan beskrevs i termer av försumlighet, bristfällig kompetens och slarv."br /" "br /" Synen på riskhantering ändrades så småningom på sent nittiotal. James Reason, en psykolog vid University of Manchester, fick stor genomslagskraft med sin bok ”Human error”. Han introducerade begreppet ”latenta fel” (eller ”latenta förhållanden”). Dessa latenta fel, menade han, var ”sjukdomsalstrare”, inbyggt i produktionssystemen. Ett produktionssystem kan leva med dessa länge, tills något händer som stör produktionssystemets ”immunsystem”. En jämförelse från det medicinska området är att våra kroppar härbärgerar många potentiellt farliga mikroorganismer, men de hålls i schack av andra mikroorganismer och vårt immunsystem som utgörs av olika vita blodkroppar. Om vårt immunsystem slås ut, som t.ex vid cellgiftsbehandling, blir dessa bakterier plötsligt väldigt farliga för vår hälsa. "br /" "br /" På samma sätt kan oförutsedda händelser inträffa i ett produktionssystem. Ett antal latenta fel byter skepnad från att vara latenta till i högsta grad aktiva, och kan orsaka en olycka."br /" "br /" Reason säger att människan i systemet, medarbetaren, går till arbetet varje dag med ambitionen att göra ett bra jobb. Medarbetaren går inte till jobbet med målsättningen att orsaka en olycka. När därför olyckor inträffar för att medarbetare gör fel, är det inte för att medarbetaren avsiktligt har gjort ett fel. Det är snarare så att medarbetaren har fångats i en ”felfälla” pga. brister i utformningen av produktionssystemet."br /" "br /" Denna avhandling rör högrisksystem, men inte högriskteknologi . Vi undersöker akut somatisk sjukvård, flygtrafikledning, apotek och en cancerklinik. Vi vill undersöka olika sätt för en organisation att få återkoppling från inträffade händelser/olyckor så att den kan lära av dessa, och förhoppningsvis förbättra säkerheten. "br /" "br /" Målet för avhandlingen är att undersöka olika sätt att åstadkomma denna återkoppling på, samt att reflektera över om några av dessa sätt är bättre än andra när det gäller att få en organisationen att dra nytta av informationen."br /" "br /" Vi vill pröva fyra olika tillvägagångssätt för att inhämta information om risker:"br /" "br /" • Retrospektivt lärande från inträffade händelser/olyckor (paper I)"br /" • Proaktivt lärande, dvs. få information om risker i systemet utan att vänta på att en olycka skall avslöja riskerna. Här använder vi en expert för att göra analysen (paper II)"br /" • Operatörscentrerat lärande. Här låter vi ”folk på golvet” stå för datainsamling och analys (paper III)"br /" • Användarcentrerat proaktivt lärande. Analysmetoden är den samma som i paper II, men med den skillnaden att vi använder en referensgrupp som består av ”folk på golvet”, dvs. det blir mindre av expertinflytande och mer av medarbetarinflytande under analysens gång (paper IV)."br /" "br /" "br /" "br /" Metoder och material"br /" "br /" Metoder"br /" "br /" I paper I använde vi MTO (Människa-Teknik-Organisation) analys som beskrivits av kärnkraftsoperatörer i Sverige. Dock gjorde vi en viss anpassning från kärnkraft till sjukvård."br /" "br /" Paper II var inspirerat av arbetet med paper I. Vid de talrika intervjuer med läkare och sköterskor som genomfördes i paper I var en återkommande reaktion: ”Varför tänkte vi inte på dessa risker innan olyckan? Det är ju så tydligt.”"br /" En annan reflektion var att retrospektiva riskanalyser kan vara bra för att förhindra en liknande olycka men att sannolikheten för att detta skulle inträffa, med exakt de samma förtecken, är minimal (jfr Tage Danielssons monolog om Harrisburg (Three Mile Island): ”Det kanske var bra det som hände i Harrisburg, fast det var osannolikt, men nu kan det osannolika inte hända i Harrisburg… igen”)."br /" "br /" Detta fick oss att börja designa en metod för proaktiv riskanalys. Åtskilliga metoder för detta hade redan publicerats men dessa var i huvudsak inriktade på tekniska system, och förutsatte en hög grad av linearitet (om A inträffar, så inträffar med stor sannolikhet B och sedan C). Vi tyckte inte att dessa metoder var applicerbara på de organisationer som var i fokus för vår forskning (sjukvård, flygtrafikledning). Dessa fungerade i högsta grad icke-linjärt, eller komplext. Resultatet var DEB (Disturbance-Effect-Barrier) analysen som användes i paper II. Med denna metod hittade vi ett antal systemsvagheter (latenta fel och bristfälliga säkerhetsbarriärer) som vi jämförde med systemsvagheter som framgick av den centrala utredningsavdelnings analys av 15 fall av separationsunderskridande ."br /" "br /" Under arbetet med paper II fick vi klart för oss att händelser med separationsunderskridande (AIRPROX) endast utgjorde en liten del av den information som kunde användas för att öka säkerheten. Regelbundet ägde händelser rum som var ”nära händelser”, dvs. en mer eller mindre okontrollerad situation som upptäcktes i tid så att händelsen inte utvecklades till ett separationsunderskridande. Vi uppfattade således att AIRPROX - händelser var ”toppen av isberget” och funderade på hur vi kunde komma åt en del av resten av isberget. Genom samtal med flygtrafikledarna upplevde vi att de hade en stor ”dold” kunskap om potentiellt riskfyllda rutiner och procedurer. Ur dessa iakttagelser kläcktes följande idé: Varför inte låta flygtrafikledarna själva stå för analysen av säkerhetsrelaterade händelser? Vi utvecklade därför en metod för operatörscentrerat lärande (paper III). I metoden ingick utbildning av flygledarna i ”systemtänk” om 1½ dag, samt formulering av vilka säkerhetsrelaterade händelser (utöver AIRPROX) de skulle rapportera och analysera."br /" "br /" Utgångspunkten för paper IV var tragisk. Författaren till denna avhandling utredde ett fall där en åtta år gammal flicka miste livet. Hon hade cancer, och fick av misstag totaldosen av ett cellgift varje dag i tre dagar, således en överdosering med 300 %. "br /" "br /" Kliniken bad oss göra en proaktiv riskanalys. Vi använde DEB - analysen igen, på processen ”att behandla patienter med cellgifter”. Denna gång använde vi en formaliserad referensgrupp av läkare och sjuksköterskor, utsedda av kliniken."br /" "br /" Material"br /" "br /" Materialet till paper I var en konsekutiv serie av rapporter (så kallade Lex Maria-anmälningar) till Socialstyrelsen i Malmö, från akut somatisk vård."br /" "br /" Underlaget för paper II var en DEB - analys av flygtrafikledningsprocessen vid Malmö Air Traffic Control Centre (ATCC Malmoe)."br /" "br /" Materialet för paper III var en utökad rapportering av säkerhetsrelaterade händelser under en sex månaders försöksperiod. Under perioden rapporterades 45 händelser som annars inte skulle ha dokumenterats och analyserats."br /" "br /" I paper IV gjorde vi en DEB - analys av risker vid behandling av patienter med cellgifter, vid en vårdenhet på onkologiska kliniken, Lunds universitetssjukhus. I analysen ingick även analys av gränssnittsproblem mellan kliniken och sjukhusapoteket (som tillverkar infusionspåsarna med cellgifter)."br /" "br /" Resultat"br /" "br /" I paper I visade vi att det var givande att använda idén om latenta fel/latenta förhållanden för analys och lärande från olyckor i sjukvården. I sju av de åtta analyserade händelserna hittade vi risker i form av inbäddade latenta fel som det var möjligt att åtgärda."br /" "br /" I paper II identifierade vi ett antal risker (latenta fel) i ett flygtrafikledningssystem med DEB - analys . Vi jämförde våra resultat med de latenta fel som framgick av 15 fall av AIRPROX, utredd av tillsynsmyndigheten (Luftfartsverket). DEB - analysen identifierade 14 av de 15 systembrister som framgick av AIRPROX utredningarna."br /" "br /" I paper III visade vi att flygledarna mycket väl kunde analysera ”lärande händelser” och föreslå preventiva åtgärder. En sådan preventiv åtgärd var behov av att utbilda flygledare i hur ett flygplans autopilot ”tänkte”. Ett annat resultat var att ganska många fall där flygplanet gjorde något oväntat, och som traditionellt av flygledarna hade betecknats som SBS (”Skit Bakom Spakarna”) faktiskt visade sig delvis ha orsakats av flygtrafikledningen, och alltså inte bara var flight deck error."br /" "br /" I paper IV förfinade vi DEB - analysen genom att från första början luta oss mot en formaliserad referensgrupp av läkare och sjuksköterskor från kliniken. Analysen visade på ett antal systemsvagheter/risker. Detta presenterades för medarbetarna vid ett möte och accepterades som förståndigt (en korridorskommentar efter mötet: ”Det var en bra sågning”!)."br /" En stor del av våra förbättringsförslag implementerades sedan."br /" "br /" "br /" Diskussion"br /" "br /" Vi diskuterar våra metoder utifrån det aktuella forskningsläget, i synnerhet diskuterar vi MTO - analys i relation till root cause analysis, och DEB - analys i relation till FMEA (Failure Mode and Effect Analysis). Vi är tämligen kritiska till båda. Vi menar att båda dessa metoder kunde förbättras och ge bättre resultat om man dels använde ”latenta förhållande konceptet”, dels tillämpade vokabulär och koncept från ISO 9000 - standarden för kvalitetsledningssystem."br /" "br /" Vi diskuterar potentialen för lärande för retrospektiva och proaktiva metoder och rekommenderar proaktiva metoder, såsom DEB - analysen."br /" "br /" Vi introducerar komplexitetsteori och relaterar denna till våra resultat. Vår konklusion är att den operatörscentrerade metoden (paper III) tycks vara den mest effektiva metoden för att påverka ett komplext system vad gäller systemets förmåga till självorganisering och önskvärda framväxande egenskaper (emergent properties).

Take The Bicycle - a project concerning the potentials and challenges in the implementation of a new Bicycle Sharing System in Copenhagen

Scipedia content — Tue, 26 Jan 2021 14:30:22 +0100

The scope of this project is to analyze and highlight potentials and challenges regarding the integration of a new Copenhagen bicycle sharing system with the public transportation, using the Copenhagen Climate Plan as our point of reference. Via a Critical Realist approach, we looked both at the physical and commuter aspects of the implementation, followed by a calculation on its expected usage and CO2 reductions. We conclude that there exist potentials in the physical implementation of the new bicycle sharing system in Copenhagen, especially in areas where there appears to be gaps in the coverage of the public transportation. However, we see a small tendency where some stations do not necessarily have the required space above surface for bicycle sharing docking stations, thereby requiring other, possibly more expensive, approaches. When it comes to meeting the requirements of the commuters, we find that there exist challenges which can seemingly only be met by high standards in the whole system. If these challenges can be met, we assess an optimal commuter usage and CO2 reduction of respectively 11,801 users and 6,099 t/year. Potentially we see that a new bicycle sharing system in Copenhagen can contribute to the achievement of visions for the transport sector set forth in the Climate Plan, but only if the observed challenges are taken into consideration, as a half-hearted approach does not seem to be gainful for the bicycle sharing system.

Link State Relationships under Incident Conditions: Using a CTM-based Dynamic Traffic Assignment Model

Scipedia content — Tue, 26 Jan 2021 14:27:26 +0100

Urban transportation networks are vulnerable to various incidents. In order to combat the negative effects due to incident-related congestion, various mitigation strategies have been proposed and implemented. The effectiveness of these congestion mitigation strategies for incident conditions largely depends on the accuracy of information regarding network conditions. Therefore, an efficient and accurate procedure to determine the link states, reflected by flows and density over time, is essential to incident management. This thesis presents a user equilibrium Dynamic Traffic Assignment (DTA) model that incorporates the Cell Transmission Model (CTM) to evaluate the temporal variation of flow and density over links, which reflect the link states of a transportation network. Encapsulation of the CTM equips the model with the capability of accepting inputs of incidents like duration and capacity reduction. Moreover, the proposed model is capable of handling multiple origin-destination (OD) pairs. By using this model, the temporal variation of flows over links can be readily evaluated. The visualized prediction of link density variations is used to investigate the link state relationships. By isolating the effects of an incident, the parallel routes of a specific OD pair display the relationship of substituting for each other, which is consistent with the general expectation regarding such parallel routes. A closer examination of the density variations confirms the existence of a substitution relationship between the unshared links of the two parallel routes. This information regarding link state relationship can be used as general guidance for incident management purposes. Master of Science

Shifting cargo from road to sea - A case study of Grieg Logistics' base-to-base transport of oil related equipment

Scipedia content — Tue, 26 Jan 2021 14:20:37 +0100

Confidential until 20 November 2012

Planejamento de microáreas urbanas considerando a dependência de energia por transporte

Scipedia content — Tue, 26 Jan 2021 14:17:37 +0100

High urban transport energy consumption is directly influenced by the level of transport energy dependence of urban forms and transport systems. Despite the introduction of new land use policies and vehicle technologies, dramatic reductions in urban transport energy dependence are not yet being observed. It is proposed that stricter land use regulations coupled with new GIS tools are required that specifically tackle the energy dependence issue. The objective of this project is to design a GIS tool that could be used within an urban development framework to dramatically reduce urban transport energy dependence. A tool was developed and named the Transport Energy Specification (TES). The TES measures urban transport energy dependency from travel behaviour, mode use and spatial data inputs. The TES is designed to be used as an energy based land-use regulation inside an urban development framework by specifying a maximum allowable energy dependency limit for land use modifications in existing urban areas and new developments. Implementation of the energy dependency land use regulation will be achieved through zoning and providing financial or other incentives for the specific desired land use activities (residential, supermarkets, kindergartens etc.). Trials were performed in Germany, New Zealand and Brazil, allowing different urban neighbourhoods and transport systems to be measured with the TES energy dependency measurement tool. The measurements confirmed similar findings from previous researchers regarding the benefits of high density areas and mixed activities in urban areas. Further analysis, trials and workshops with local governments will set in motion the process of including the TES into future urban development policy. O alto consumo de energia nos transportes urbanos é diretamente influenciado pelo grau de dependência energética das formas urbanas e dos sistemas de transportes. Como o desenvolvimento de novas tecnologias veiculares e políticas de uso do solo ainda não foi capaz de produzir reduções significativas no grau de dependência energética dos transportes urbanos, defende-se aqui que uma legislação mais restritiva de uso do solo, combinada com novas ferramentas de Sistemas de Informações Geográficas, constitui-se em uma condição necessária para enfrentar a questão da dependência energética. O objetivo deste projeto é desenvolver uma estrutura conceitual em plataforma SIG, que possa ser usada como ferramenta de planejamento para o desenvolvimento urbano, capaz de reduzir drasticamente a dependência energética do transporte urbano. A ferramenta desenvolvida recebeu a designação Especificação de Energia para Transporte (ou TES, da sigla em inglês Transport Energy Specification), e destina-se a medir o nível de dependência do transporte urbano em relação a aspectos como o comportamento de viagens, escolha modal e aspectos espaciais dos elementos urbanos. A TES foi concebida para ser usada como elemento regulatório do uso do solo, sob o ponto de vista da eficiência energética, a partir da especificação de um valor máximo para o limite de dependência energética decorrente de modificações em áreas urbanas existentes ou em novos loteamentos. A implantação de uma estratégia de regulação de uso do solo baseada no conceito de dependência energética pode ser alcançada através de uma legislação de zoneamento e de incentivos, inclusive financeiros, para determinadas tipos de uso (residências, supermercados, creches, etc.). Estudos de caso com a ferramenta proposta para avaliação do grau de dependência energética foram conduzidos em cidades selecionadas na Alemanha, Nova Zelândia e Brasil, de forma a contemplar diferentes tipos de arranjos de vizinhança e de sistemas de transportes. Os resultados encontrados confirmaram os benefícios, já apontados por outros pesquisadores, de áreas com elevadas densidades e uso misto em zonas urbanas. Novas análises, estudos de caso e discussões com governos locais são necessários para fazer do TES parte de políticas futuras de desenvolvimento urbano.

Mapper Power: Geographical Information Systems, Agenda-Setting and Policy Design

Scipedia content — Tue, 26 Jan 2021 14:11:23 +0100

xtabstractWhen we look at the world around us, we see the physical world and we interpret this physical world. We can view the features of this physical world in several ways. What we can also do, which among other things, distinguishes us from animals, is pretend. Pretend this world is different from what we see; pretend that we are different from what we are. Let’s do so and play some ‘make believe’.

Managing Traffic Congestion-Case study of Hangzhou

Scipedia content — Tue, 26 Jan 2021 14:10:54 +0100

Hangzhou is located in the east of China as one of most important cities in Yangtze River delta. With the rapid development of economy in the last three decades, Hangzhou, like many other Chinese cities, has met some challenges. Traffic congestion in Hangzhou is the one I want to talk about in this master thesis. Traffic congestion became to trouble people’s lives in the past decade, following with dramatic urbanization. People spent much more time on travel, and their quality of lives were threatened. My thesis includes four parts: introduction of Hangzhou, theories and instruments on reducing traffic congestion, instruments have been used in Hangzhou, and recommendation for Hangzhou’s transportation. Firstly, Hangzhou’s background information was discussed. Population and number of vehicles can be seen as the main reasons for traffic congestion in Hangzhou. Also other problems are listed: old roads structure, mingling of different transits, low efficient of public transit, and poor management. There are policy and planning from national and local government, which is related to Hangzhou’s traffic system. At the end of this chapter I presented my research question: how to reduce Hangzhou’s traffic congestion. Secondly, I discussed theories and instruments have been used to reduce traffic congestion. Traffic principles were introduced: triple convergence and ‘offsetting by growth’, which should not be ignored when people talk about traffic congestion. Then I separated instruments, which used to reduce traffic congestion, into three parts: physical instruments, market instruments, regulatory instruments, and discussed some instruments in these three parts. Thirdly, my attention was focused on Hangzhou’s efforts on reducing traffic congestion. These instruments also can be divided into three parts. Since Hangzhou is in the process of urbanization, physical instruments were used most widely to reduce traffic congestion in Hangzhou. But few market instruments and regulatory instruments have been adopted. I compared instruments used in Hangzhou with other cities’ instruments, and analyzed effects of instruments used in these cites. Through comparison, I found that integrated instruments are necessary when people want to reduce traffic congestion. Only physical instruments or market instruments can not reduce traffic congestion efficiently. At last, I list some accomendations for Hangzhou to reduce traffic congestion, which could be classified as supply side instruments and demand side instruments. Hangzhou has put many efforts in supply side, but few in demand side, and this unbalance between supply side and demand side makes effects of reducing traffic congestion limited. In general, supply side approaches are similar with physical instruments, and demand side approaches are similar with market instruments and regulatory instruments. Hangzhou should continue to improve physical instruments, such as improving public transport system, which can gives people more choices for traveling. Also Hangzhou should put much more efforts on demand side instruments, which can control private cars directly.

Une approche de l'Ingénierie de la Résilience pour l'évaluation de la variabilité de la performance : développement et application de la Functional Resonance Analysis Method pour l'évaluation de la sécurité dans la gestion du trafic aérien

Scipedia content — Tue, 26 Jan 2021 14:01:49 +0100

Maîtres de thèse : Eric RIGAUD et Denis BESNARD; This thesis demonstrates the need to develop systemic safety assessment methods to account for the effect of performance variability on air traffic management safety. Like most modern socio-technical systems, air traffic management is so complex that it is impossible for it to be completely described. As consequence, performance cannot be completely specified because it must vary to meet performance demands. Performance variability is an inevitable asset to ensure the functioning of an organisation and at the same time can be harmful for system safety when it combines in an unexpected manner. This argument clearly indicates the need for safety assessment methods that can deal with performance variability. The Functional Resonance Analysis Method (FRAM) has the ability to model performance variability. However parts of the FRAM can be improved to expand its capabilities to evaluate performance variability. This thesis addresses this weakness and develops a methodology for the evaluation of performance variability. The methodology has been applied on a safety assessment case study for the German air traffic management domain. The results have been compared with the official results of a traditional safety assessment. The comparison shows the added valued of the proposed methodology. In particular it illustrates the possibility to identify emergent risks and human contribution to system safety.; Cette thèse montre la nécessité de développer des méthodes systémiques d'estimation de la sécurité permettant de tenir compte de l'effet de la variabilité de la performance sur la sécurité de la gestion du trafic aérien. Comme la plupart des systèmes socio-techniques modernes, la gestion du trafic aérien est tellement complexe que il lui est impossible d'être complètement décrite. Comme conséquence directe, sa performance ne peut être complètement explicitée, car elle doit varier afin de correspondre aux conditions réelles. La variabilité de la performance est un inévitable atout pour assurer le fonctionnement d'une organisation. Mais en même temps elle peut représenter une atteinte à la sécurité du système lorsqu'elle se déroule de manière indésirable ou inattendue. Cet argument indique la nécessité de méthodes d'estimation de la sécurité qui puissent traiter la variabilité de la performance. La Functional Resonance Analysis Method (FRAM) a la capacité de modéliser la variabilité de la performance. Cependant, certains points de la FRAM pourraient être améliorés dans le but de développer ses capacités a évaluer la variabilité de la performance. Cette thèse aborde ce point faible et développe une méthodologie pour l'évaluation de la variabilité de la performance. Cette méthodologie a été appliquée dans une étude de cas dans le domaine de la Gestion du Trafic Aérien Allemand. Ses résultats ont été comparés aux résultats officiels obtenus en utilisant l'estimation de la sécurité traditionnelle. La comparaison montre la valeur ajoutée de la méthodologie proposée. En particulier elle illustre la possibilité d'identifier des risques émergents et la contribution humaine a la sécurité d'un système.

Elektrikli Araç Motorunun Soğutma Sistem Tasarımı

Scipedia content — Tue, 26 Jan 2021 13:55:57 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011

Methodological proposal for energy planning in the development of urban areas. The potential of integrating strategies and solutions in urban morphology and mobility, buildings, energy and environment, on Agua Branca urban operation study-case, Sao Paulo

Scipedia content — Tue, 26 Jan 2021 13:54:27 +0100

O objeto da presente tese é o desenvolvimento de uma proposta metodológica para planejamento energético no desenvolvimento de áreas urbanas, na escala de distritos, bairros e unidades de vizinhança. A metodologia proposta é aplicável a estudos de desenvolvimento de novas áreas urbanas, distritos ou bairros e estudos para requalificação de áreas urbanas já ocupadas, como ferramenta de suporte ao planejamento e ao processo decisório. Inicialmente, foi produzida uma base referencial dos principais condicionantes para o planejamento energético urbano, segundo o escopo considerado nesse trabalho de pesquisa. Nessa etapa foram identificadas e analisadas as interdependências entre esses fatores e sua participação no consumo energético e nas emissões de poluentes. A proposta metodológica está estruturada em dois módulos principais: Módulo 1 - Gerenciamento da Demanda de Energia, envolvendo aspectos relacionados à Morfologia Urbana, Mobilidade Urbana e Edificações, tais como densidade populacional e construída, uso e ocupação do solo, geometria de quadras e cânion urbano, sistema de transporte urbano de passageiros, sistema viário, tecnologias veiculares e combustíveis, soluções passivas em conforto ambiental e substituição tecnológica de equipamentos em edificações; e Módulo 2 - Gerenciamento da Oferta de Energia, incluindo sistemas de geração e distribuição de energia elétrica e térmica para aquecimento e resfriamento em escala urbana, inclusive com aproveitamento de recursos energéticos residuais e renováveis. Dos Módulos 1 e 2 resultam os níveis de consumo de energia e as emissões totais de poluentes, incluindo Gases de Efeito Estufa e poluentes locais. Na composição da proposta metodológica participam variáveis e parâmetros relacionados aos condicionantes de planejamento energético urbano, bem como procedimentos de cálculo que integram e compatibilizam as configurações urbanas quanto à morfologia, mobilidade, edificações, e geração de energia. Os procedimentos foram sistematizados em um conjunto de planilhas eletrônicas e gráficos comparativos, desenvolvidos para aferição da proposta metodológica, suporte na visualização de resultados e indicadores e posterior aplicação como ferramenta no planejamento de áreas urbanas. A proposta metodológica foi aplicada no caso da Operação Urbana Água Branca, no Município de São Paulo, ficando demonstrado o potencial de integração de estratégias e comprovando a tese em questão. Nas duzentas e dezessete diferentes situações configuradas por meio da metodologia proposta, foi possível identificar não apenas importantes potenciais quantitativos, mas também a contribuição relativa dos diversos condicionantes para o resultado global, em termos energéticos, urbanísticos e ambientais. Além dos cenários apresentados, a proposta metodológica permite que diversos outros possam ser configurados para outras áreas urbanas a serem desenvolvidas ou requalificadas, desde que as variáveis e os parâmetros sejam adequadamente adaptados a cada realidade. The subject of this thesis is the development of a methodology for energy planning in the development of urban areas, in the scale of districts and neighborhoods. The proposed methodology has two main applications as a tool to support strategic planning and decision-making process: studies for the development of new urban areas, districts or neighborhoods, and studies for rehabilitation of urban areas already used. Initially, a conceptual and technical approach was done about the main constraints for urban energy planning, according to the scope considered in this research. In this stage, the interrelationships among these factors and their impact in terms of energy consumption and pollutant emissions were identified and analyzed. The proposed methodology is organized into two main modules: Module 1 - Energy Demand Management, involving aspects of urban morphology, urban mobility and buildings, such as population density and built area, land use, urban blocks and urban canyon geometry, urban transport, road system, vehicle and fuel technologies, passive solutions to environmental comfort and technological replacement of equipment in buildings; and Module 2 - Energy Supply Management, including district and local systems for generating and distributing electricity and steam for heating and cooling purpose, including the use of renewable and waste energy resources. Levels of energy consumption and the total emission of pollutants, including greenhouse gases and local pollutants, result from the Modules 1 and 2. The proposed methodology involves variables and parameters related to the constraints of urban energy planning as well as calculation procedures that integrate and match the urban settings under consideration, as urban morphology, mobility, buildings, power generation and district systems. The procedures were systematized into a set of spreadsheets and charts developed to verify the proposed methodology, visualization support of results and indicators, and later application as a tool for planning of urban areas. The proposed methodology was applied to the Agua Branca Urban Operation study-case, in the city of Sao Paulo, in which the potential of integrating strategies was demonstrated. In thirty-six different situations defined by using the proposed methodology, it was possible to identify not only important quantitative potentials but also the relative contribution of various constraints to the overall result in terms of energy, urban and environmental issues. In addition to the scenarios presented, the proposed methodology allows the configuration of several other options to different urban areas to be developed or rehabilitated, but variables and parameters need to be properly adapted to each situation.

Elektrikli Araçlarda Şarj Duruma Bağlı Rota Optimizasyonu

Scipedia content — Tue, 26 Jan 2021 13:29:39 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011

Energy resource management in smart grids considering an Intensive use of electric vehicles

Scipedia content — Tue, 26 Jan 2021 13:21:21 +0100

The introduction of electricity markets and integration of Distributed Generation (DG) have been influencing the power system’s structure change. Recently, the smart grid concept has been introduced, to guarantee a more efficient operation of the power system using the advantages of this new paradigm. Basically, a smart grid is a structure that integrates different players, considering constant communication between them to improve power system operation and management. One of the players revealing a big importance in this context is the Virtual Power Player (VPP). In the transportation sector the Electric Vehicle (EV) is arising as an alternative to conventional vehicles propel by fossil fuels. The power system can benefit from this massive introduction of EVs, taking advantage on EVs’ ability to connect to the electric network to charge, and on the future expectation of EVs ability to discharge to the network using the Vehicle-to-Grid (V2G) capacity. This thesis proposes alternative strategies to control these two EV modes with the objective of enhancing the management of the power system. Moreover, power system must ensure the trips of EVs that will be connected to the electric network. The EV user specifies a certain amount of energy that will be necessary to charge, in order to ensure the distance to travel. The introduction of EVs in the power system turns the Energy Resource Management (ERM) under a smart grid environment, into a complex problem that can take several minutes or hours to reach the optimal solution. Adequate optimization techniques are required to accommodate this kind of complexity while solving the ERM problem in a reasonable execution time. This thesis presents a tool that solves the ERM considering the intensive use of EVs in the smart grid context. The objective is to obtain the minimum cost of ERM considering: the operation cost of DG, the cost of the energy acquired to external suppliers, the EV users payments and remuneration and penalty costs. This tool is directed to VPPs that manage specific network areas, where a high penetration level of EVs is expected to be connected in these areas. The ERM is solved using two methodologies: the adaptation of a deterministic technique proposed in a previous work, and the adaptation of the Simulated Annealing (SA) technique. With the purpose of improving the SA performance for this case, three heuristics are additionally proposed, taking advantage on the particularities and specificities of an ERM with these characteristics. A set of case studies are presented in this thesis, considering a 32 bus distribution network and up to 3000 EVs. The first case study solves the scheduling without considering EVs, to be used as a reference case for comparisons with the proposed approaches. The second case study evaluates the complexity of the ERM with the integration of EVs. The third case study evaluates the performance of scheduling with different control modes for EVs. These control modes, combined with the proposed SA approach and with the developed heuristics, aim at improving the quality of the ERM, while reducing drastically its execution time. The proposed control modes are: uncoordinated charging, smart charging and V2G capability. The fourth and final case study presents the ERM approach applied to consecutive days. A introdução dos mercados de electricidade e integração da produção distribuída tem causado alterações na estrutura e no modo de operação dos sistemas eléctricos de energia. Recentemente, o conceito de SmartGrid foi introduzido com o objectivo de garantir uma operação mais eficiente dos sistemas eléctricos de energia. Basicamente, uma SmartGrid é uma estrutura que envolve as diferentes entidades, e considera uma constante interacção e comunicação entre as mesmas, para melhorar a operação do sistema eléctrico de energia. Umas das entidades com grande relevância neste contexto são os Virtual Power Players (VPP). Os Veículos Eléctricos (VE) têm surgido no sector dos transportes como uma alternativa aos veículos convencionais abastecidos por combustíveis fósseis. O sistema eléctrico de energia pode beneficiar dessa introdução massiva de VEs, aproveitando a sua capacidade de ligação à rede eléctrica para a carga dos veículos, e numa perspectiva mais vanguardista para descarga, fornecendo energia à rede. Nesta tese são propostas estratégias de gestão das cargas/descargas do VE com o objectivo de melhorar a operação do sistema eléctrico de energia. No processo de gestão de recursos, o operador da rede ou agregadores deverão considerar as necessidades dos utilizadores dos VEs, nomeadamente garantir a existência de energia suficiente nas baterias para que os utilizadores possam efectuar as viagens que tem programadas. A introdução dos veículos eléctricos nos sistemas eléctricos de energia torna a gestão de recurso energéticos num ambiente de SmartGrid, um problema complexo que pode levar vários minutos ou horas para se obter uma solução. Considerando o período para o qual é necessário efectuar o escalonamento, que normalmente é para o dia seguinte ou para os 15 minutos seguintes no caso de escalonamento em tempo real, é necessário desenvolver algoritmos que permitam a resolução dos problemas em tempos muito razoáveis. Nesta tese é apresentada uma ferramenta que permite a resolução do problema do escalonamento de recursos, considerando o uso intensivo de VEs no contexto das SmartGrid. O objectivo é obter o custo mínimo de operação, considerando: o custo de operação da produção distribuída, o custo da energia adquirida a fornecedores externos, a remuneração do uso de VEs e os custos associados ao incumprimento de condições contratuais. A ferramenta desenvolvida é direccionada para a utilização pelos VPPs que gerem áreas de rede específicas, com um nível de penetração elevado de VEs. O escalonamento de recursos é resolvido usando duas metodologias: a adaptação de uma técnica determinista proposta em trabalhos anteriores, e a adaptação da técnica de Simulated Annealing, sendo propostas três abordagens para melhorar a solução obtida através da técnica de Simulated Annealing. Diversos casos de estudo são apresentados, considerando uma rede de distribuição com 32 barramentos e cenários de evolução da penetração de VE até 3000 veículos. O primeiro caso de estudo, usado como um caso de referência para comparações com as abordagens propostas, resolve o escalonamento de recursos sem considerar VEs. O segundo caso avalia a complexidade do escalonamento de recursos com a integração de VEs, permitindo testar as técnicas propostas. O terceiro caso avalia o desempenho do escalonamento com diferentes modos de controlo de EVs. O quarto caso de estudo apresenta a abordagem aplicada ao escalonamento de recursos em diversos dias consecutivos.

Power Control Systems in a Flywheel based All-Electric Driveline

Scipedia content — Tue, 26 Jan 2021 13:15:09 +0100

Flywheel systems are attractive in hybrid and electric vehicles due to their ability to handle power during acceleration and braking. The combination of a flywheel device with a battery source has several advantages such as high peak power capacity, high energy density and reduction in the number of charge/discharge cycles of the battery. A flywheel based all-electric driveline is investigated in this thesis. The novelty of the system consists in the use of a double wound flywheel machine, which divides the system in two different power levels. Due to this configuration, the system becomes efficient and can handle the power developed during fast dynamical processes. The complete driveline consists of three main components: the battery, the flywheel machine and the wheel motor. The High-Power (HP) side of the driveline connects the flywheel machine to the wheel motor, whereas the Low-Power (LP) side connects the flywheel machine to the battery. The connections of different components of the system are made electrically through power converter devices. The present thesis focuses on the electrical converters and control strategies used in the flywheel based all-electric driveline. The control of power converters is responsible for the logic and functionality of the driveline, being a challenging step within this project. Different power converter topologies have been investigated: a DC/DC plus a DC/AC converter on the LP side, and an AC/DC/AC converter on the HP side. The design and assembly of the power electronics and their control scheme have been successfully implemented. Different control strategies have been suggested and a complete scaled driveline has been assembled and tested based on previous simulation results. Results have confirmed the functionality of the driveline, where smoothed output power has been obtained from the battery, whereas the flywheel handles power transients on the traction side. An average efficiency of about 87% (battery to wheels) has been obtained. The power converter systems have been shown to be efficient and robust, with control strategies able to handle the peak energy flow in the system. A regenerative braking strategy has been simulated and a wheel-to-wheel efficiency of about 80% has been estimated.

Otoyol Trafiği Yönetiminde Akıllı Sistem Yaklaşımı: Katılım Denetimi Örneği Ve Farklı Denetim Algoritmalarının Başarım Sınaması

Scipedia content — Tue, 26 Jan 2021 13:14:16 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011

Environmental Health in Nicaragua : Key Environmental Challenges--Study 1

Scipedia content — Mon, 25 Jan 2021 20:22:41 +0100

Globally, an estimated 24 percent of the disease burden (healthy life years lost) and an estimated 23 percent of all deaths (premature mortality) are attributable to environmental risks (World Health Organization, or WHO 2006). The burden of disease is unequally shared, with the children and the poor being particularly affected. Among children between the ages 0 and 14, the proportion of deaths attributable to environmental risks, such as poor water and sanitation, indoor air pollution and vector-borne diseases, is estimated to be as high as 36 percent (WHO 2006). Several key messages have emerged from the process of putting together this study: (i) environmental health risks impose a significant burden on Nicaraguas economy, amounting to 2.6 billion Nicaraguan Cordoba (NIO) or 2.4 percent of the countrys Gross Domestic Product (GDP), and result in premature deaths and infections, especially in children under five; (ii) cost-effective interventions to address these environmental health risks exist and should be prioritized in Nicaragua; (iii) country-specific health and environmental data are somewhat limited, especially in the case of air quality, and data collection and monitoring need to be further strengthened; and (iv) the capacity of Ministry of Environment and Natural Resources (MARENA) and Ministry of Health (MINSA) staff to conduct environmental health costing analysis needs to be strengthened through proper training.

Incorporating TDM into the Land Development Process

Scipedia content — Mon, 25 Jan 2021 20:13:49 +0100

Due to unfamiliarity with the plans, processes and procedures of the local government land development process, transportation demand management (TDM) professionals can be frustrated in their efforts to improve mobility and reduce traffic congestion. This report provides detailed information to transportation professionals regarding how to incorporate TDM strategies into the land development process. The report documents efforts to secure TDM strategies as part of development approvals, summarizes the long range planning groundwork that frames the land development process, provides several case study examples from Florida and nationwide and also identifies several institutional barriers to the use of TDM as part of the land development process. A major finding is that transportation professionals interested in using TDM in land development must get involved long before development proposals are submitted. This requires participation in review and updates of the metropolitan planning organization long range transportation plan and transportation improvement program as well as local government comprehensive plans. Further, it involves appraising how well the local government land development regulations implement the intent of the comprehensive plan and reviewing traffic analysis methodology and underlying assumptions. These ground laying activities will begin the integration of TDM principles and strategies into the land use and transportation planning processes resulting in physical infrastructure, regulatory tools and operations management to support TDM as part of the solution as land development proceeds.

Review of ?Deepwater Horizon Release Estimate of Rate by PIV?

Scipedia content — Mon, 25 Jan 2021 20:09:35 +0100

The Plume Calculation Team (PCT) conducted high quality work within a very short period of time, in spite of needing to use less than ideal quality videos provided by British Petroleum (BP), especially those made before the cutoff of the riser above the Blow Out Preventer (BOP) on June 3, 2010. There are at least two valid approaches for estimating the oil discharge coming out from the Deepwater Horizon broken pipeline and its riser, using BP videotapes. One method is to estimate the exit velocity directly with the use of the Particle Image Velocimetry (PIV). The second method is to use a buoyant plume analysis to determine the exit velocity. The PCT used both of these methods.

Model zavarovanja odgovornosti operatorja multimodalnega transporta

Scipedia content — Mon, 25 Jan 2021 19:42:49 +0100

Multimodal transportation means transporting goods from a pickup point, where the operator receives the goods, all the way to the delivery location, using at least two different means of transportation, covered under the same multimodal transport contract and by only one document, regardless of the number or type of transportation vehicles used. The key factor to the optimal operation of multimodal transportation is the multimodal transport operator. It is up to this individual to compensate for various unpredictable circumstances, the complexity of the business processes, nature’s whims and carelessness. He must also organize and execute multimodal transport in all stages. Due to the above mentioned dangers and the fact that the area of liability insurance for multimodal transport operators is still being neglected, this article raises some valid points in favour of a proposal that would cover all of the transportation means as well as all the accompanying activities with a single insurance policy. The model includes 17 elements of liability insurance for a multimodal transport operator and all values which quantify the insurance elements in 2009 as well as the projected values for 2015, when progress is expected in the areas pertaining to the implementation of economical processes concerning transit development, as well as values for 2025, representing a period of innovation, reconstruction, optimization and modernization. With this supposed model for liability insurance of a multimodal transport operator, the foundation is laid for a liability insurance which would be used by a multimodal transport operator. Multimodalni transport predstavlja transport blaga od mesta, kjer je operator multimodalnega transporta prevzel blago za transport pa vse do mesta predaje blaga, z uporabo najmanj dveh različnih načinov transporta, na osnovi ene pogodbe o multimodalnem transportu in enega dokumenta, ne glede na vrsto in število uporabljenih prevoznih sredstev. Ključni faktor optimalnega funkcioniranja multimodalnega transporta predstavlja operator multimodalnega transporta. Ta mora, zaradi spleta nepredvidljivih okoliščin, zapletenosti poslovnih procesov, muhavosti narave in nepazljivosti, dobro organizirati in izvrševati multimodalni transport na vseh nivojih. Zaradi omenjenih nevarnosti in dejstva, da se še vedno ne posveča dovolj pozornosti obvladovanju in strategiji zavarovanja odgovornosti operatorja v multimodalnem transportu, ki bi skozi pregled obstoječe ureditve multimodalnega transporta z eno samo zavarovalno pogodbo krile vse vrste transporta in spremljajoče dejavnosti odgovornosti operatorja multimodalnega transporta, se v tem članku poraja potreba, da predlagamo model zavarovanja odgovornosti operatorja multimodalnega transporta. Model zavarovanja odgovornosti operatorja multimodalnega transporta zajema 17 elementov in vse vrednosti, s katerimi se kvantificirajo elementi zavarovanja v letu 2009, kot tudi predpostavljene vrednosti v letu 2015, ko se pričakuje napredek v implementaciji projektov ekonomskega procesa razvoja tranzicije ter vrednosti v letu 2025, ki bi predstavljale obdobje inovacij, rekonstrukcij, optimizacij in modernizacij. S predpostavljenim modelom za zavarovanje odgovornosti operatorja multimodalnega transporta je dana osnova za zavarovanje odgovornosti, ki bi ga koristil operator multimodalnega transporta.

Urban Transport Projects : Patterns and Trends in Lending, 1999-2009

Scipedia content — Mon, 25 Jan 2021 19:38:24 +0100

The study consisted of developing a compendium of profiles for all free-standing urban transport projects funded by the Bank in calendar years from 1999 through 2009, followed by a first-pass synthesis of patterns and trends. There were 50 such projects. In addition, profiles were done for several projects from this period which were classified as urban or transport, but with significant urban transport components. Also, profiles were done for several operations approved before 1999 or after 2009, because they formed organic sequences with some operations in the 1999-2009 batches, in the same city or the same country. In all, profiles were done for 56 operations. A list of these projects is in annex one. Full profiles are in annex two, grouped by the geographic region, and in the chronological order according to the date of loan approval. The sources consulted in writing the profiles included project appraisal documents, loan and project agreements, restructuring papers, and implementation completion reports. In addition to this introduction, the synthesis report has four chapters. In the next (second) chapter, a brief overview is provided of the batch of projects for which the profiles were done. Chapter three reviews urban transport programs by region. Chapter four presents outcome ratings for completed projects and issues related to their success or otherwise. Chapter five discusses the fit between the projects and a provisional version of the Bank's urban transport strategy.

Detecting Anomalies in Sensor Signals using Database Technology

Scipedia content — Mon, 25 Jan 2021 19:32:15 +0100

Signals are usually post-processed in order to enhance their accuracy and reliability. For instance, sensor data frommoving objects data are often processed by tracking systems which allows for enhancing the provided kinematic information. In high-level fusion systems, this kinematic information can be combined with additional domain-specific data which allows for detecting object behavior and threat patterns. These systems contribute to situation awareness by employing patterns which characterize situations of interest. The used patterns may vary over time and depend on the specific questions to be investigated.Database systems provide a flexible way of combining data, and continuous queries allowing an ongoing automatic evaluation of search patterns. In this chapter, we present a way of using database systems as the central component in a higher-level fusion system. We discuss how patterns for the detection of anomalies in tracking scenarios can be expressed in relational algebra. Finally, we present an application of such a system for monitoring and analyzing air traffic using a commercial database management system.

Cameroon Economic Update, January 2011, Issue No. 1 : Time for the Lion to Wake Up?

Scipedia content — Mon, 25 Jan 2021 19:15:54 +0100

This Cameroon economic update, the World Bank is launching a program of short, crisp and more frequent country economic reports. These economic updates will analyze the trends and constraints in Cameroon's economic development. Each issue, produced bi-annually, will provide an update of recent economic developments as well as a special focus on a selected topical issue. The economic updates aim to share knowledge and stimulate debate among those interested in improving the economic management of Cameroon and unleashing its enormous potential. The notes thereby offer another voice on economic issues in Cameroon, and an additional platform for engagement, learning and change. The report's special focus on the telecommunication sector. Cameroon has been hit by the global economic and financial crisis over the past two years, as reflected in steep declines in the price and demand for its export commodities including oil, timber, rubber, cotton and aluminum. However, the upturn in the global economy and measures taken by the authorities to stimulate domestic production, preliminary indications suggest that economic activity is recovering. Gross domestic product (GDP) growth in 2010 is estimated to have reached 3 percent on the back of stronger non-oil activities, which expanded by about 4 percent (particularly food crops, forestry, construction, transport, and telecoms). Data on private credit growth corroborate this assessment. Cameroon is a relatively small and mature oil producer, where oil production is declining. Depleting reserves, aging equipment, and more recently postponements of some development projects and investments because of the financial crisis explain this profile. The contribution of this sector to GDP growth has been mostly negative in recent years: oil production is estimated to have contracted by a further 16 percent in 2010 (to 23.2 million barrels).

Do konkurenčnosti s celovitim in inovativnim logističnim managementom doba

Scipedia content — Mon, 25 Jan 2021 19:12:36 +0100

In the age of global expansion of business operations and contemporary way of life the material and information flows in and between different companies are growing rapidly they are thus becoming more and more difficult to manage. Had business functions in companies been dealt with separately until now (purchase, production, finances, sale, etc.), today the emphasis is placed on their integration due to their interdependence. By studying supply chains inside and between business partners, companies can gain competitive advantage and become more adjustable, taking the increasingly changing market circumstances into account. This enables them to meet consumers' demands and expectations requisitely holistically. Taking all the crucial activities into account, the logistics management plays a key role in the companies facing the challenges of the new millennium. Based on the numerous megatrends, which influence each and every business entity, this article aims to explain the increasing strategic importance of logistics management. The latter may not be dealt with one-sidedly as a cost moreover, the key aspects such as competitiveness as well as long-term existence of a company must also be considered. Innovation and systemic thinking in it and about it are needed. Doba globalne ekspanzije poslovanja in sodobnega načina življenja povzroča hitro in vedno težje obvladljivo rast blagovnih in informacijskih tokov v podjetjih in med njimi. Če smo nekdaj obravnavali poslovne funkcije v podjetju (nabavo, proizvodnjo, finance, prodajo …) ločeno, se danes stroka vse bolj posveča njihovemu povezovanju zaradi soodvisnosti. Proučevanje oskrbnih verig v podjetju in med poslovnimi partnerji daje podjetju možnosti, da postane bolj konkurenčno in bolj prilagodljivo, glede na vedno hitrejše spreminjanje tržnih razmer. To pomeni čimbolj celovito zadovoljevanje odjemalčevih zahtev oz. pričakovanj. Pri spletu teh aktivnosti ima ključno vlogo menedžment logistike kot odgovor in strategija podjetij, pripravljenih na izzive 21. stoletja. V članku smo želeli pokazati, kako se na številne t.i. megatrende8, ki vedno bolj vplivajo na poslovanje slehernega gospodarskega subjekta, povečuje strateški pomen menedžmenta logistike. Slednje ne smemo enostransko obravnavati kot strošek, ampak celoviteje, tj. kot ključni vir konkurenčnosti in dolgoročnega obstoja podjetja. Pospeševati moramo inoviranje in sistemsko razmišljanje o in v njej.

A Strategic Approach to Climate Change in the Philippines : An Assessment of Low-Carbon Interventions in the Transport and Power Sectors

Scipedia content — Mon, 25 Jan 2021 19:03:37 +0100

Globally, the Philippines is a minor emitter of greenhouse gases (GHGs), but cost-effective mitigation present opportunities that should be captured, noting that the country is one of the signatory member states to the 1992 United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. The country accounts for less than 0.3 percent of global GHG emissions in 2004.4 However, emissions are on the rise from both energy-use and land-use changes. Even if the absolute scale will remain small, there are increasing number of development projects under preparation, which offers opportunities for cost-effective mitigation and adaptation measures. The Philippine Government's response to the climate change challenge has been active institutionally noting the recent restructuring of the Presidential task force on climate change. However, a clear strategy and action plan are still lacking. The international donor community, including development partners such as the Asian Development Bank (ADB), the United Nations International Strategy for Disaster Reduction (ISDR), the Millennium Challenge Corporation (MCC), and the United Nations Development Program (UNDP), is actively engaged in addressing climate change in the Philippines. There are several initiatives on capacity building for GHG accounting, monitoring and reporting, for preparation of a second National Communication to the UNFCCC, governance, renewable energy, urban air quality management, and forest management. There are likewise several World Bank supported climate change-related activities, with nine active operations. These encompass primarily energy sector operations.

Measures to Reduce the Economic and Social Impact of High Fuel Prices

Scipedia content — Mon, 25 Jan 2021 18:49:36 +0100

High volatility in the world prices of petroleum has been a characteristic feature of the global economy in the last decade. World petroleum prices increased four-fold between 2004 and 2008 and, and following a drop in prices in the second half of 2008, petroleum prices have been rising again, and they are several times higher than they were two decades ago. Since high and volatility of prices is likely to be a permanent feature of the global economy for the foreseeable future, they merit a reconsideration of the national transport and taxation policies that were put in place when fuel prices were not such a significant component of trade-related transactions costs in Sub-Saharan Africa (SSA) countries. Transport practices that were based on the assumption of low price of fuel are not sustainable, and policies neglect fuel efficiency considerations through lowering the fuel consumption of vehicles measures are no longer sustainable. Efficient and low transport cost is essential to achieve regional economic integration and strengthen Africa's competitiveness in external markets. Higher diesel prices also impact on the prices of all other goods which use diesel as an intermediate input. The most significant among them with implications for the poor in low-income developing countries is food, on which the poor spend a disproportionately high share of their total household expenditures. This report is in three parts in the first part, transport fuel prices in the countries of SSA are compared with those of other regions of the world. The comparison is not only in terms of the actual retail prices but also, but taking account of per capita incomes and truck revenues, also in terms of affordability. This Part also provides evidence of the make-up of transport fuel prices in SSA countries, as a first step in assessing how they can be dealt with. The second part provides new evidence of the impact of these high fuel prices on the export competiveness of a sample of six SSA countries. It also provides a shorter description of the results of a study of the impact of fuel prices on logistics costs in Central America, since so far there have not been any studies of the impact of high transport fuel prices on logistics and food costs in SSA countries. The third part deals with the ways in which the impact of high transport fuel prices can be addressed. Two main areas of action are described, those that would reduce the retail price of transport fuel and those that would increase fuel efficiency, so they impact of high prices would be reduced. This section focuses on diesel fuel, as this is by far the most used by the trucks that transport export products and are involved in domestic logistics. This section concludes with some ideas on what could be done next to make progress on implementing the most promising ideas for reducing the impact of high transport fuel prices.

Fluid-structure interaction with pipe-wall viscoelasticity during water hammer

Scipedia content — Mon, 25 Jan 2021 18:48:46 +0100

Fluid-structure interaction (FSI) due to water hammer in a pipeline which has viscoelastic wall behaviour is studied. Appropriate governing equations are derived and numerically solved. In the numerical implementation of the hydraulic and structural equations, viscoelasticity is incorporated using the Kelvin-Voigt mechanical model. The equations are solved by two different approaches, namely the Method of Characteristics - Finite Element Method (MOCFEM) and full MOC. In both approaches two important effects of FSI in fluid-filled pipes, namely Poisson and junction coupling, are taken into account. The study proposes a more comprehensive model for studying fluid transients in pipelines as compared to previous works, which take into account either FSI or viscoelasticity. To verify the proposed mathematical model and its numerical solutions, the following problems are investigated: axial vibration of a viscoelastic bar subjected to a step uniaxial loading, FSI in an elastic pipe, and hydraulic transients in a pressurized polyethylene pipe without FSI. The results of each case are checked with available exact and experimental results. Then, to study the simultaneous effects of FSI and viscoelasticity, which is the new element of the present research, one problem is solved by the two different numerical approaches. Both numerical methods give the same results, thus confirming the correctness of the solutions. Keywords: water hammer; fluid transient; pressure surge; fluid-structure interaction; pipe vibration; plastic pipe; viscoelasticity

Vpliv motečih dejavnikov na sodelovanje v izvedbi logističnega outsourcinga

Scipedia content — Mon, 25 Jan 2021 18:40:31 +0100

The purpose of this paper is to present the research results of a study conducted in the Slovene logistics market of conflicts and opportunism as disturbing factors while examining their impact on cooperation in logistics outsourcing performance. Relationship variables are proposed that directly or indirectly affect logistics performance and conceptualize the hypotheses based on causal linkages for the constructs. On the basis of extant literature and new argumentations that are derived from in-depth interviews of logistics experts, including providers and customers, the measurement and structural models are empirically analyzed. Existing measurement scales for the constructs are slightly modified for this analysis. Purification testing and measurement for validity and reliability are performed. Multivariate statistical methods are utilized and hypotheses are tested. The results show that conflicts have a significantly negative impact on cooperation between customers and logistics service providers (LSPs), while opportunism does not play an important role in these relationships. The observed antecedents of logistics outsourcing performance in the model account for 58.4% of the variance of the goal achievement and 36.5% of the variance of the exceeded goal. Namen članka je predstaviti rezultate raziskave, izvedene na slovenskem logističnem trgu, o vplivu konfliktov in oportunističnega obnašanja kot motečih dejavnikov na sodelovanje v izvedbi outsourcinga. Predlagali smo spremenljivke, ki imajo neposredni ali posredni vpliv na njegovo izvedbo, in postavili hipoteze o njihovem medsebojnem vplivu. Po temeljitem pregledu obstoječe literature in novimi spoznanji, pridobljenimi z analizo poglobljenih pogovorov z logističnimi strokovnjaki pri logističnih ponudnikih in njihovih odjemalcih, smo oblikovali merski in strukturni model. Obstoječe merske lestvice za konstrukte smo za potrebe raziskave nekoliko modificirali. Analizo zanesljivosti in veljavnosti merskih lestvic ter merskega in strukturnega modela smo izvedli z multivariatnimi statističnimi metodami. S testiranjem postavljenih domnev smo potrdili močan negativen vpliv konfliktov na sodelovanje med odjemalcem in logističnim ponudnikom, medtem ko oportunistično obnašanje v njunem odnosu nima vidnega mesta. Obravnavani predhodniki izvedbe outsourcinga v modelu pojasnjujejo 58,4 % delež skupne variance v spremenljivki doseganja ciljev in njen 36,5 % delež v spremenljivki preseganja ciljev outsourcinga.

The tax treatment of company cars, commuting and optimal congestion taxes

Scipedia content — Mon, 25 Jan 2021 18:38:38 +0100

In Europe, the preferential tax treatment of company cars implies that many employees receive a company car as part of their compensation package. In this paper, we consider a model in which wages and the decision whether or not to provide a company car are the result of direct negotiation between employer and employee. Using this framework, we theoretically and numerically study first- and second-best optimal tax policies on labour and transport markets, focusing on the role of the tax treatment of company cars. We obtain the following results. First, higher labour taxes and a more favourable tax treatment of company cars raise the fraction employees that receives a company car; congestion and congestion tolls reduce it. Second, in countries that provide large implicit subsidies to company cars, eliminating the preferential tax treatment of company cars may be an imperfect but quite effective substitute for currently unavailable congestion tolls. The numerical illustration, calibrated using Belgian data, suggests that it yields about half the welfare gain attainable through optimal congestion taxes. Third, the favourable tax treatment of company cars justifies large public transport subsidies; the numerical results are consistent with zero public transport fares. Finally, we find that earlier models that ignored the preferential tax treatment of company cars may have substantially underestimated optimal congestion tolls in Europe. The numerical illustration suggests that about one third of the optimal congestion toll we obtain can be attributed to the current tax treatment of company cars. (C) 2011 Elsevier Ltd. All rights reserved.

Technical Report on the Minimization of Potential Air Conflicts using Speed Control

Scipedia content — Mon, 25 Jan 2021 18:20:45 +0100

This report provides an insight into the mathematical methods developed to model the speed regulation problem in Air Traffic Flow Management. The speed regulation problem aims at optimizing aircraft speeds along their flights in order to smooth the air traffic flow. We chose to develop a linear framework for the speed regulation problem therefore most of the techniques presented aim at providing a linear formulation of the model.

Urban transport and environmental justice - status quo in the USA and implications for Germany

Scipedia content — Mon, 25 Jan 2021 18:18:20 +0100

This report looks at the status quo of policies, legislation and discourse relating to urban road transport and environmental justice in the US. It presents the findings from literature study and a series of interviews conducted during a trip to the US in the summer of 2011. Interview partners came from research, regional and national non-governmental organizations (NGOs) and from various levels of administration. Interviews were conducted in Los Angeles, the Bay Area, Sacramento and Davis (all California) as well as Washington, D.C. and Boston, MA. The report gives an overview over the current research activities in the US relating to urban transport and environmental justice (EJ), it presents the legal framework for EJ related campaigning and decision making and relates some examples of current issues and campaigns in this area in the regions visited. The text also conveys the evaluations and opinions of those who were interviewed (in anonymous form). The trip was funded by the American Council on Germany through the 2011 McCloy Fellowship in Environmental Policy.

Energy-Aware Traffic Engineering

Scipedia content — Mon, 25 Jan 2021 18:02:14 +0100

Energy consumption of the Internet is already substantial and it is likely to increase as operators deploy faster equipment to handle popular bandwidth-intensive services, such as streaming and video-on-demand. Existing work on energy saving considers local adaptation relying primarily on hardware-based techniques, such as sleeping and rate adaptation. We argue that a complete solution requires a network-wide approach that works in conjunction with local measures. However, traditional traffic engineering objectives do not include energy. This paper presents Energy-Aware Traffic engineering (EATe), a technique that takes energy consumption into account while optimizing for low link utilization and high end-host sending rates. EATe uses a scalable, online technique to spread the load among multiple paths so as to increase energy savings. Our extensive ns-2 simulations over realistic topologies show that EATe succeeds in moving 21% of the links to the sleep state, while keeping the same sending rates and being close to the optimal energy-aware solution. Further, we demonstrate that EATe successfully handles changes in traffic load and quickly restores a low overall energy state. Alternatively, EATe can move links to lower energy levels, resulting in energy savings of 8%. Finally, EATe can succeed in making 16% of active routers sleep. "p"QC 20140704

Côte d’Ivoire’s Infrastructure : A Continental Perspective

Scipedia content — Mon, 25 Jan 2021 17:59:12 +0100

This study is a product of the Africa Infrastructure Country Diagnostic (AICD), a project designed to expand the world's knowledge of physical infrastructure in Africa. Infrastructure contributed 1.8 percentage points to Cote d'Ivoire's annual per capita Gross Domestic Product (GDP) growth in the mid-2000. Raising the country's infrastructure endowment to that of the region's middle-income countries could boost annual growth by a further two percentage points per capita. Cote d'Ivoire made major strides with respect to infrastructure during the 1990s. As a result, the country has broad-reaching national backbones in the road, energy, and Information and Communication Technologies (ICT) sectors, and relatively high levels of household coverage for utility services. However, much ground was lost to conflict in the mid-2000s. Very little investment has taken place in the last fifteen years, leading to recent power shortages, the deterioration of the road network, and the deceleration of progress on safe water access. Cote d'Ivoire's most pressing challenge will be to regain the financial equilibrium needed to restore a reliable energy supply. Reestablishing the prominence of Abidjan's port will require investments in terminal capacity, as well as road and rail infrastructure upgrades on hinterland linkages. The underfunding of road maintenance must also be addressed. Another challenge lies in sanitation, as it is currently unlikely that the country will meet the associated millennium development goal. This report presents the key AICD findings for Cote d'Ivoire, allowing the country's infrastructure situation to be benchmarked against that of its African peers. A social and economic crisis in Cote d'Ivoire has crippled its growth trajectory, which had been that of a middle-income country. It will therefore be compared to low-income countries (fragile and non-fragile groups) and middle-income countries, as well as immediate regional neighbors in West Africa. The study presented several methodological issues.

Uncertainty in diffusion of competing technologies and application to electric vehicles

Scipedia content — Mon, 25 Jan 2021 17:57:24 +0100

The diffusion of innovations is an important process and its models have appli-cations in many fields, with particular relevance in technological forecast. The logistic equation is one of most important models in this context. Extensions of this approach as the Lotka-Volterra model have been developed to include the effect of mutual influences between technologies such as competition. However, many of the parameters entering this description are uncertain, difficult to estimate or simply unknown, particularly at early stages of the diffusion. Here, a systematic way to study the effect of uncertain or unknown parameters on the future diffusion of interacting innovations is proposed. The input required is a general qualitative understanding of the system: is the mutual influence positive or negative and does it apply symmetrically to either technology? Since the pa-rameters enter the problem via a set of coupled non-linear differential equa-tions, the approach proposed here goes beyond simple Monte-Carlo-like meth-ods where the result is an explicit function of the parameters. The methodology is developed in detail and applied the case of three types of upcoming electric vehicle propulsion technologies. The findings indicate that competition between electric vehicles and mild hybrid vehicles implies a slow decline of the latter. The approach can easily be generalised to include other initial conditions, more technologies or other technological areas to find stable results for future market evolution independent of specific parameters.

Pipeline Transport of Diesel Fuel, Operation

Scipedia content — Mon, 25 Jan 2021 17:48:36 +0100

Ghana's Infrastructure : A Continental Perspective

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

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.

PAT-1 safety analysis report addendum.

Scipedia content — Mon, 25 Jan 2021 17:27:48 +0100

The Plutonium Air Transportable Package, Model PAT-1, is certified under Title 10, Code of Federal Regulations Part 71 by the U.S. Nuclear Regulatory Commission (NRC) per Certificate of Compliance (CoC) USA/0361B(U)F-96 (currently Revision 9). The purpose of this SAR Addendum is to incorporate plutonium (Pu) metal as a new payload for the PAT-1 package. The Pu metal is packed in an inner container (designated the T-Ampoule) that replaces the PC-1 inner container. The documentation and results from analysis contained in this addendum demonstrate that the replacement of the PC-1 and associated packaging material with the T-Ampoule and associated packaging with the addition of the plutonium metal content are not significant with respect to the design, operating characteristics, or safe performance of the containment system and prevention of criticality when the package is subjected to the tests specified in 10 CFR 71.71, 71.73 and 71.74.

Transport Energy Efficiency

Scipedia content — Mon, 25 Jan 2021 17:21:21 +0100

Transport is the sector with the highest final energy consumption and, without any significant policy changes, is forecast to remain so. In 2008, the IEA published 25 energy efficiency recommendations, among which four are for the transport sector. The recommendations focus on road transport and include policies on improving tyre energy efficiency, fuel economy standards for both light-duty vehicles and heavy-duty vehicles, and eco-driving. Implementation of the recommendations has been weaker in the transport sector than others. This paper updates the progress that has been made in implementing the transport energy efficiency recommendations in IEA countries since March 2009. Many countries have in the last year moved from "planning to implement" to "implementation underway", but none have fully implemented all transport energy efficiency recommendations. The IEA calls therefore for full and immediate implementation of the recommendations."

Safe automotive software

Scipedia content — Mon, 25 Jan 2021 17:10:59 +0100

For automotive manufacturers and tier-1 suppliers, the upcoming safety standard ISO 26262 results in new requirements for the development of embedded electronics and software. In particular, the variety of driver assistance systems that autonomously influence the driving dynamics of a vehicle may have a high risk potential and require development in accordance with the normative guidelines. But especially for those systems whose function is typically not based solely on hardware but on complex software algorithms, safety certification can be very complex or even impossible. In this paper the problems of development of vehicle systems according to ISO 26262 are described. Finally an approach for a safety-oriented reference architecture is presented that introduces adaptive software safety cages. This architecture enables application of formal verification methods. Supported by multisensor data fusion this allows to reduce safety requirements for vehicle control systems.

Achieving Sustainable Development in Jordan : Country Environmental Analysis

Scipedia content — Mon, 25 Jan 2021 16:58:43 +0100

This Country Environmental Analysis (CEA) has been developed by the World Bank in cooperation with the Government of Jordan. It aims to integrate environment into development and poverty reduction priorities. The CEA will be a vital instrument for designing Jordans future policies, by integrating the economic policy tools in our decision making processes. As the latest economic crises and its implications have shown, an economic model that is based on consumption alone cannot be sustained; accordingly many countries identified the need to green their economics as the base for sustainable growth and development. Jordans green economic initiative will enhance social integration, economic growth an environmental sustainability within one focused, measured and stable economic plan. Jordan is a small country that is rich in human capital; the green journey will be a twenty years program to retrofit our infrastructure, to become energy, water and resource efficient. The recommendations identified in this document will be the main drivers for the environmental policies in the country. The issue of adequate incentives for better quantity management clearly remains important, but is not addressed in this report. After the national agenda was established, it appears that the reduction of water related subsidies and the creation of incentives for allocating water to higher value added uses are being recognized as necessities that public policies will address in the future.

Baltic States and Poland Trade Logistics Review : Enhancing Trade Competitiveness by Improving Transport and Logistics

Scipedia content — Mon, 25 Jan 2021 16:48:33 +0100

The Baltic States; Estonia, Latvia and Lithuania and Poland are situated along strategic trade corridors within Europe, constituting the EUs eastern border with Russia and other CIS countries. EU membership has triggered rapid economic growth for the Baltic States and Poland due to the removal of trade barriers and reduced transaction costs. A heavy influx of EU grants has targeted development and improvement of transport infrastructure, and this support will continue until 2015. The EU grants are largely used for development of international corridors, which play a key role in strengthening the competitiveness of these new member states. Since their accession to the EU in 2004, these countries enjoyed remarkable growth. While the countries underwent varying degrees of contractions in 2009, signs of recovery are showing albeit with considerable uncertainty in the future. Growth in Estonia, Latvia and Lithuania in recent years has been unsustainable and was driven by a disproportionate increase in the non-tradable sector (construction, financial intermediation, real estate). This has had negative implications for competitiveness. The global economic crisis in 2009 has ended Poland?s fast economic expansion over the recent years, but in contrast to its neighbors Poland has avoided a decline in economic activity. Over the medium term, growth in Poland is expected to accelerate steadily in line with an improving external environment. The Baltic States and Poland are relatively competitive in trade logistics and have initiated reforms to facilitate trade, compared to their eastern neighbors, particularly Russia. Despite the plunge in 2008, freight transport and logistics development in the region has potential to continue to grow in the medium-term as some signs of recovery have begun to appear. The current economic situation has triggered a significant overcapacity of transport and warehousing which is characterized by very low prices for these services. While Poland remains relatively stable, Estonia, Latvia, and Lithuania are exhibiting higher vulnerability to external shocks. The most critical bottlenecks of transport logistics in the Baltic States and Poland are found in the deteriorating condition of their transport infrastructure, particularly that of road networks, lessdeveloped intermodal connections, and inefficiency of custom processing at border crossing points. Deteriorating road condition in these countries is largely due to inadequate maintenance and a comprehensive asset management system, albeit improving. Intermodal connections that are often inefficient are partly attributed to institutional arrangement that lacks inter-agency collaboration at the level of policy development and public investment. Custom procedures are particularly cumbersome and inefficient at the borders to non-EU member states. Nevertheless, the Baltic States and Poland have relative strengths in efficiency of domestic transport/logistics, cost-efficiency of trucking industry, and price-competitive port operation. The report various recommendations for strategic policy priorities for the Baltic States and Poland to leverage their own strengths to respond to various opportunities and challenges.

Analiza sigurnosti delovanja žičniških naprav po metodi drevesa napak

Scipedia content — Mon, 25 Jan 2021 16:41:59 +0100

This paper examines the reliability of the operation of cableway systems in Slovenia, which has major impact on the quality of service in the mountain tourism, mainly in wintertime. Different types of cableway installations in Slovenia were captured in a sample and fault tree analysis (FTA) was made on the basis of the obtained data. The paper presents the results of the analysis. With these results it is possible to determine the probability of faults of different types of cableways, which types of faults have the greatest impact on the termination of operation, which components of cableways fail most, what is the impact of age of cableways on the occurrence of the faults. Finally, an attempt was made to find if occurrence of faults on individual cableway installation has also impact on traffic on this cableway due to reduced quality of service. Članek proučuje sigurnost delovanja žičniških naprav v Sloveniji, katere imajo velik vpliv na kakovost storitev v gorskem turizmu, največ v zimskem času. V vzorec so bile zajete slovenske žičniške naprave različnih vrst in na osnovi pridobljenih podatkov o odpovedi njihovega delovanja je bila narejena analiza drevesa napak (FTA). V članku so predstavljeni rezultati analize s pomočjo katere se je dalo ugotoviti, kakšna je verjetnost odpovedi posameznih vrst žičniških naprav, katere vrste napak imajo največji vpliv na odpovedi, kateri sklopi žičniških naprav največkrat odpovedo, kakšen vpliv ima starost žičniških naprav na pojav napak. Na koncu se je poskušalo ugotoviti tudi, ali ima pojav napak na posamezni žičniški napravi tudi vpliv na promet zaradi zmanjšane kakovosti storitve.

The Lake Charles CCS Project

Scipedia content — Mon, 25 Jan 2021 16:39:54 +0100

The Lake Charles CCS Project is a large-scale industrial carbon capture and sequestration (CCS) project which will demonstrate advanced technologies that capture and sequester carbon dioxide (CO{sub 2}) emissions from industrial sources into underground formations. Specifically the Lake Charles CCS Project will accelerate commercialization of large-scale CO{sub 2} storage from industrial sources by leveraging synergy between a proposed petroleum coke to chemicals plant (the LCC Gasification Project) and the largest integrated anthropogenic CO{sub 2} capture, transport, and monitored sequestration program in the U.S. Gulf Coast Region. The Lake Charles CCS Project will promote the expansion of EOR in Texas and Louisiana and supply greater energy security by expanding domestic energy supplies. The capture, compression, pipeline, injection, and monitoring infrastructure will continue to sequester CO{sub 2} for many years after the completion of the term of the DOE agreement. The objectives of this project are expected to be fulfilled by working through two distinct phases. The overall objective of Phase 1 was to develop a fully definitive project basis for a competitive Renewal Application process to proceed into Phase 2 - Design, Construction and Operations. Phase 1 includes the studies attached hereto that will establish: the engineering design basis for the capture, compression and transportation of CO{sub 2} from the LCC Gasification Project, and the criteria and specifications for a monitoring, verification and accounting (MVA) plan at the Hastings oil field in Texas. The overall objective of Phase 2, provided a successful competitive down-selection, is to execute design, construction and operations of three capital projects: (1) the CO{sub 2} capture and compression equipment, (2) a Connector Pipeline from the LLC Gasification Project to the Green Pipeline owned by Denbury and an affiliate of Denbury, and (3) a comprehensive MVA system at the Hastings oil field.

The Contribution of Natural Gas Vehicles to Sustainable Transport

Scipedia content — Mon, 25 Jan 2021 16:30:27 +0100

The transport sector is currently responsible for 23% of energy-related CO2 emissions, and transport associated CO2 emissions will more than double by 2050. This working paper evaluates the potential costs and benefits of using natural gas as a vehicle fuel for road transportation, as well as the policy related to its market development.

Risky Business? : HIV Knowledge, Attitudes, and Behavior Among At-Risk Mobile Workers in Turkey

Scipedia content — Mon, 25 Jan 2021 15:03:24 +0100

This study focuses on, what is believed to be, a key client group of sex workers: mobile workers. While several studies have been conducted in Turkey on sex workers, little evidence exists on their clients, the demand side of the commercial sex market. Research from other countries has shown that mobile workers, who are often working-age males spending significant time away from home, are more likely to have multiple sexual partners and visit sex workers (World Bank, 2009; Kulis et al., 2009; Marck, 1999). The objective of this study is to determine the HIV knowledge, awareness, and behaviors among four mobile worker groups in Turkey that may have elevated risks for HIV infection and transmission: sailors, truck drivers, construction, and tourism workers. International transportation, construction, and tourism are some of the fastest growing sectors of Turkey's economy, and mobile workers in these sectors are believed to be one of the main HIV transmission routes for future infections (Tumer and Unal, 2006). It is important to note two caveats of this study. First, no biomarker data (e.g., HIV testing) was collected from these workers, so conclusions regarding HIV prevalence or concentration of the epidemic cannot be made. Second, the sample did not include other at-risk groups or the general population, so it is difficult to know whether the behaviors are more or less risky in other population groups. Where possible, comparisons with other studies or countries are presented, but there are likely important differences in sampling and methodology. The major contribution of this study, however, is that it characterizes the risk factors within the mobile worker population in Turkey.

Scoop Technical Report: Year 2011

Scipedia content — Mon, 25 Jan 2021 14:58:23 +0100

This report deals with the technical solution that was implemented for the Grand Cooperative Driving Challenge (GCDC) 2011. The GCDC involved developing a system to drive a vehicle autonomously in specific situations. Some reflections on the design process are also included. The goal of the report is to make the user understand the technical solution and the motivations behind the design choices made. "p"QC 20121112

Market and Service Orientation of Public Transportation : Swedish-Indonesian Cooperation Transportation Research and Education 2000 to 2010

Scipedia content — Mon, 25 Jan 2021 14:47:27 +0100

This is anaccount of a program of research cooperation within the field of publictransportation. The University of Gajah Mada in Yogyakarta, Indonesian andKarlstad University in Sweden has worked together in this program. The reformedand re-organized systems of public transportation in Sweden and Indonesia havebeen the topics of exchange. The program started around 2000 and has developedover some 10 years. The Service and Market Oriented Research Group (SAMOT) at Karlstad University conducts multidisciplinary and internationally recognized research via active collaboration with trade and industry, public sector players, and universities. In doing so, SAMOT will contribute to the long-term sustainable development of passenger transportation services.

What sustainable road transport future? Trends and policy options

Scipedia content — Mon, 25 Jan 2021 14:44:04 +0100

A brief review of long run projections of demand for road transport suggests that problems related to road network congestion and greenhouse gas emissions are likely to become more pressing than they are now. Hence we review, from a macroscopic perspective, popular policy measures to address these problems: stimulating modal shift, regulating land use to reduce car use, and boosting low carbon technology adoption to reduce greenhouse gas emissions. We find that these policies can produce tangible results, but that they may have unintended consequences that drive up costs considerably.

Transport Infrastructure Investment and Demand Uncertainty

Scipedia content — Mon, 25 Jan 2021 14:42:48 +0100

In transportation planning there can be long lead times to adapt capacity. This paper addresses two questions. First, in a one mode world (say rail or road), what is the optimal capacity choice when faced with uncertain demand, long lead times and congestion. Using a simple analytical model it is shown that when demand is inelastic, it is socially optimal to invest more than if only the expected level of demand is taken into account. In this case it may be beneficial to overinvest in capacity because congestion costs are a convex function of relative use. This result holds with or without optimal tolling. The second question deals with two competing modes and where only one mode has long lead times for capacity while the other has flexible capacity. This is typical for the competition between High Speed Rail and air for the medium distance trips (500 to 1000 km), or for the competition between inland waterways and trucks for freight. We find that overinvestment is less justified because the substitute mode can more easily absorb the high demand outcomes. ispartof: CES - Discussion paper series (DPS) 08.09 pages:1-20 status: published

Eliciting the Regulation of an Economic System: The Case of the French Rail Industry

Scipedia content — Mon, 25 Jan 2021 12:46:08 +0100

Based on the modern theory of regulation, the analysis aims to characterize the effective economic regulation of the French railway industry. The methodology consists in econometrically testing various scenarios of regulation and determining which of these best fits the data. Using aggregate data on the overall passenger traffic for the incumbent French rail operator (RO), SNCF, the two behavioral hypotheses of reference which we consider âabsence of regulation of the rail operator which acts as a pure monopoly, and price regulation of services supplied by the ROâ are both statistically significant and do not subtract from each other. This result is certainly related to the fact that passenger services include both high speed train services, for which the RO has some entrepreneurial freedom, and regional transport services, which are regulated by local authorities. In any case however, as the presence of unobservable efforts exerted by the RO to improve its productivity is statistically relevant, one concludes that the RO is not fully and properly regulated. This emphasizes that the design of policy reforms must account for the incentives they create on the RO. The analysis also shows that the most statistically significant scenarios are the ones in which the access tariff imposed by the infrastructure manager is such that the revenue generated by the access tariff is equal to the infrastructure spending. The pricing of the access to the infrastructure network therefore does not seem to be governed by economic principles, but more by budget considerations. While data limitations does neither allow to understand all the facets of a complex reality, nor to claim a high level of precision in the measure of all the parameters of interest, we believe however that we provide an objective methodology to characterize the optimal economic policies for the railway sector, in particular because it yields realistic estimates of the main structural parameters. Indeed the empirical results suggest that the railway industry as a whole exhibits increasing returns to scale, which incidentally is not compatible with the presence of multiple firms. In addition, the elasticity of demand for railway transport is relatively high, an indication of the competitive constraints this mode of transport faces from other transport modes or induced traffic.

Efficient Solutions for Urban Mobility - Policies, Strategies and Measures

Scipedia content — Mon, 25 Jan 2021 12:40:30 +0100

Over the past few decades, particularly in urban areas, mobility needs have significantly grown and changed as a result of the normal social and economic development. The mobility is nowadays a very diverse and complex reality, in reason of the tendency for a more disperse residential occupation and for a more decentralized location of most commercial and service activities, as well as of different population mobility habits resulting from their increased wealth. As a consequence urban mobility has been ever more dependent on the private car and, in many cases, by the existence of inefficient and costly public transport systems, with obvious negative impacts at the environmental, social and economic levels for the society as a all. It is also relevant to refer that in some European Union (EU) countries transports use up to 30% of the energy used by the different human activity sectors and is responsible for 25-30% of the total of greenhouse gases (EEA, 2000; Civitas, 2006), with the car being responsible for as much as 50% of the emissions produced by passenger transport systems. It is also important to notice the negative impacts that transport systems can, and often have, over several quality of life aspects. In many cases these systems invade many of the cities public spaces, which are otherwise used in many other activities such as leisure. This situation has led to an increased emphasis being placed in the development of transport strategies and solutions within the Sustainable Development Global Agenda (Commission of the European Communities, 2006). The EU Green Paper over Urban Environment, the EU Treaty, the successive EU environment and transport action programs, the Rio de Janeiro UN Conference on Environment and Development or the different UN conferences culminating with HABITAT II, constitute some of the initiatives witch have been raising the sustainability issue and, in this context, have been discussing the future of urban mobility. An urban strategic planning process, taking into consideration the urban area fundamental characteristics and its population needs, is thus an essential framework for the identification of adequate sustainable transport policies. These planning processes can vary significantly but generally it can be said that they are evermore inter-disciplinary and focused mainly on two different but complementary areas. 12

Travel Demand Model with Heterogeneous Users and Endogenous Congestion: An application to optimal pricing of bus services

Scipedia content — Mon, 25 Jan 2021 12:31:18 +0100

We formulate and estimate a structural model for travel demand, in which users have hetero- geneous preferences and make their transport decisions considering the network congestion. A key component in the model is that users have incomplete information about the preferences of other users in the network and they behave strategically when they make transportation decisions (mode and number of trips). Therefore, the congestion level is endogenously determinate in the equilibrium of the game played by users. For the estimation, we use the first order conditions of the users' utility maximization problem to derive the likelihood function and apply Bayesian methods for inference. Using data from Santiago, Chile, the estimated demand elasticities are consistent with results reported in the literature and the parameters confirm the effect of the congestion on the individuals' preferences. Finally, we compute optimal nonlinear prices for buses in Santiago, Chile. As a result, the nonlinear pricing schedule produces total benefits slightly greater than the linear pricing. Also, nonlinear pricing implies fewer individuals making trips by bus, but a higher number of trips per individual.

Urban Microclimate and Traffic Monitoring with Mobile Wireless Sensor Networks

Scipedia content — Mon, 25 Jan 2021 12:11:50 +0100

Climate is usually defined as the average of the atmospheric conditions over both an extended period of time and a large region. Small scale patterns of climate resulting from the combined influence of topography, urban buildings structure, watercourses, vegetation, are known as microclimates, which refers to a specific site or location. The microclimate scale may be at the level of a settlement (urban or rural), neighborhood, cluster, street or buffer space in between buildings or within the building itself. Specifically, the dispersion and dilution of air pollutants emitted by vehicles is one of the most investigated topics within urban meteorology, for its fundamental impact on the environment affecting cities of all sizes. This issues concern the average and peak values of various air pollutants as well as their temporal trends and spatial variability. The accurate detection of these values might be advantageously exploited by public authorities to better plan the public and private transportation by evaluating the impact on people health, while controlling the greenhouse phenomenon. As the unpredictable nature of a climate variations requires an incessant and ubiquitous sensing,Wireless Sensor Networks (WSNs) represent a key technology for environmental monitoring, hazard detection and, consequently, for decision making (Martinez et al., 2004). A WSN is designed to be self-configuring and independent from any pre-existing infrastructure, being composed of a large number of elementary Sensor Nodes (SNs) that can be large-scale deployed with small installation and maintenance costs. Literature contains several examples of frameworks for evaluating the urban air quality with WSNs, as it is reported in (Santini et al., 2008). In addition, in (Cordova-Lopez et al., 2007) it is addressed the monitoring of exhaust and environmental pollution through the use of WSN and GIS technology. As micro-climate monitoring usually requires deploying a large number of measurement tools, in (Shu-Chiung et al., 2009) it is adopted vehicular wireless sensor networks (VWSNs) approach to reduce system complexity, while achieving fine-grainedmonitoring. Another aspect strictly correlated with microclimate establishment is represented by the ecologic footprint of traffic congestion due to inefficient traffic management. As a consequence, an increasing number of cities are going to develop intelligent transport system (ITS) as an approach to harmonize roads and vehicles in optimized and green paths. ITSs involves several technologies as advanced informatics, data communications and transmissions, electronics and computer control with the aim of real-time traffic reporting and alerting. Such a framework allows remote operation management and self-configuration of traffic flows, as well as 1

The Economics of Traffic Congestion

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

This essential two-volume collection contains the most influential articles written over the past eight decades that contribute to an understanding of the economics of traffic congestion. The first volume explores the classic contributions on congestion and road pricing and includes papers in dynamic models and second-best congestion pricing. The second volume analyses ownership arrangements such as private roads, investment and financing, urban land use, social acceptability and distributional aspects of road pricing.

Contingency Plans for Air Traffic Management

Scipedia content — Mon, 25 Jan 2021 12:05:58 +0100

We present two heuristics based on constraint technology that solve the problem of generating air traffic management contingency plans, which are used in the case of a catastrophic infrastructure failure within EUROCONTROL, the European Organisation for the Safety of Air Navigation. Of the heuristics presented, one is based on constraint-based local search and tabu search, and the other one is a constraint programming and large neighbourhood search hybrid algorithm. The heuristics show that it is feasible to automate the development of contingency plans, which is currently done by human experts; this is desirable for several reasons, for example it would allow the contingency plans to be generated with an increased frequency. The generated plans were evaluated, by EUROCONTROL, to be as good as the human-made ones.

Multiple User-Class Dynamic Stochastic Assignment for a Route Guidance Strategy

Scipedia content — Mon, 25 Jan 2021 11:50:08 +0100

Traffic information systems have become a major issue in many countries as a modern technology for alleviating traffic congestion in urban areas. Pre-trip or en-route real-time travel information regarding traffic conditions can enhance driversâ knowledge of the situation in road networks and may assist in driversâ decisions such as the choice of departure time, route, and destination. In facts, several papers have shown that traffic information yields benefits to drivers such as travel-time reduction and the avoidance of traffic accidents, among others. In considering the potential benefits of alternative driver information systems, it is also necessary to evaluate the potential of adverse impacts that improved information may have. Ben-Akiva et al. (1991) explained this phenomenon in terms of three elements: oversaturation; overreaction; and concentration. Among them, overreaction and concentration are the principal causes of adverse effects. Overreaction occurs when driversâ reactions to traffic information cause congestion to transfer from one road to another. It may also generate fluctuations in road usage. Overreaction may occur if drivers respond too sensitively to information on current traffic conditions. Concentration may occur when drivers choose a specific route in a very short period. In order to implement the strategies of an Intelligent Transportation System (ITS), it is necessary to predict the temporal evolution of the traffic pattern on a congested transportation network, where travel demands and travel costs vary over time and space. For urban areas, dynamic models are mainly considered as they describe how commuters adjust their travel decisions concerning routes and departure times. Moreover, to model the impact of information provision by an ITS, it is necessary to develop a multi-class model given there are different classes of users in a transportation network, who respond in differing ways to traffic information. In this chapter, a multiple-user-class dynamic stochastic assignment (MDSA) model is introduced to reflect drivers who have varying perceptual errors and varying dynamic traffic behaviors. MDSA is an extended version of a static single-user-class assignment. The driver's route-choice mechanism is based on his/her past experience of the road traffic conditions during prior days of travel. Some information-provision strategies that are involved in a route-guidance system are also introduced for the effective use of the systems.

Kalman Filter Applications for Traffic Management

Scipedia content — Mon, 25 Jan 2021 11:45:51 +0100

An onÂline calibration approach for dynamic traffic assignment systems has been developed. The approach is general and flexible and makes no assumptions on the type of the DTA system, the models or the data that it can handle. Therefore, it is applicable to a wide variety of tools including simulationÂbased and analytical, as well as microscopic and macroscopic models. The objective of the onÂline calibration approach is to introduce a systematic procedure that will use the available data to steer the model parameters to values closer to the realized ones. The output of the onÂline calibration is therefore a set of parameter values that --when used as input for traffic estimation and prediction-- minimizes the discrepancy between the simulated (estimated and predicted) and the observed traffic conditions. The scope of the onÂline calibration is neither to duplicate nor to substitute for the offÂline calibration process. Instead, the two processes are complementary and synergistic in nature. The onÂline calibration problem is formulated as a stateÂspace model. StateÂspace models have been extensively studied and efficient algorithms have been developed, such as the Kalman Filter for linear models. Because of the nonÂlinear nature of the onÂline calibration formulation, modified Kalman Filter methodologies have been presented. The most straightforward extension is the Extended Kalman Filter (EKF), in which optimal quantities are approximated via first order Taylor series expansion (linearization) of the appropriate equations. The Limiting EKF is a variation of the EKF that eliminates the need to perform the most computationally intensive steps of the algorithm onÂline. The use of the Limiting EKF provides dramatic improvements in terms of computational performance. The Unscented Kalman Filter (UKF) is an alternative filter that uses a deterministic sampling approach. The computational complexity of the UKF is of the same order as that of the EKF. Empirical results suggest that joint onÂline calibration of demand and supply parameters can improve estimation and prediction accuracy of a DTA system. While the results obtained from this real network application are promising, they should be validated in further empirical studies. In particular, the scalability of the approach to larger, more complex networks needs to be investigated. The results also suggest that --in this application-- the EKF has more desirable properties than the UKF (which may be expected to have superior performance over the EKF), while the UKF seems to perform better in terms of speeds than in terms of counts. Other researchers have also encountered situations where the UKF does not outperform the EKF, e.g. LaViola, J. J., Jr. (2003) and van Rhijn et al. (2005). The Limiting EKF provides accuracy comparable to that of the best algorithm (EKF), while providing order(s) of magnitude improvement in computational performance. Furthermore, the LimEKF algorithm is that it requires a single function evaluation irrespective of the dimension of the state vector (while the computational complexity of the EKF and UKF algorithms increases proportionally with the state dimension). This property makes this an attractive algorithm for largeÂscale applications.

Risk and the role of scientific input for contingency planning: a response to the April 2010 Eyjafjallajökull volcano eruption

Scipedia content — Mon, 25 Jan 2021 11:36:59 +0100

International audience; This chapter focuses on the insights that the Eyjafjallajokull eruption in April 2010 provided for the coordination of scientific input to decision-making across the European aviation industries. Volcanic eruptions are part of a wider class of natural risks, including earthquakes, pandemics, and regional fires etc., that have to be managed collectively. These, in turn, form a sub-set of adverse events that also include man-made catastrophes, such as terrorist attacks, pollution etc. Natural and man-made risks are collectively known as contingency events. They are characterized by relatively low expected probabilities but extremely high potential consequences. The public increasingly expect commercial and regulatory agencies to adopt a precautionary approach to such events. These expectations extend not just from the time before any incident occurs but also under the stress and time pressure of decision-making during a contingency. If we are to meet these expectations, it is important that operational decision-making is informed by accurate scientific information on a wide range of issues. It should not be shaped by ad hoc political pressures, although these will inevitably play a role.

Building Innovation Pipelines through Computer-Aided Innovation: 4th IFIP WG 5.4 Working Conference, CAI 2011, Strasbourg, France, June 30 – July 1, 2011. Proceedings

Scipedia content — Mon, 25 Jan 2021 11:08:03 +0100

International audience; Book Front Matter of AICT 355

Document type: Book

IDriver - Human Machine Interface for Autonomous Cars

Scipedia content — Mon, 25 Jan 2021 10:56:21 +0100

Modern cars are equipped with a variety of sensors, advanced driver assistance systems and user interfaces nowadays. To benefit from these systems and to optimally support the driver in his monitoring and decision making process, efficient human-machine interfaces play an important part. This paper describes the second release of iDriver, an iPad software solution which was developed to navigate and remote control autonomous cars, to give access to live sensor data and useful data about the car state, as there are, e.g., current speed, engine and gear state. The software was used and evaluated in our two fully autonomous research cars âSpirit of Berlinâ and âMade in Germanyâ.

A Reinforcement Learning approach for designing and optimizing interaction strategies for a Human-Machine Interface of a Partially Autonomous Driver Assistance System

Scipedia content — Mon, 25 Jan 2021 10:49:16 +0100

The FP7 EU project ISi-PADAS (Integrated Human Modelling and Simulation to support Human Error Risk Analysis of Partially Autonomous Driver Assistance Systems) endeavours to conceive an intelligent system called PADAS (Partially Autonomous Driver Assistance System) for aiding human drivers in driving safely by providing them with pertinent and accurate information in real time about the external situation and by acting as a co-pilot in emergency conditions. The system interacts with the driver through a HumanâMachine Interface (HMI) installed on the vehicle using an adequate Warning and Intervention Strategy (WIS). In this paper, the design of the PADAS HMI as well as a decision-theoretic approach for deriving an optimal WIS are described.

A vehicular mobility model based on real traffic counting data

Scipedia content — Mon, 25 Jan 2021 10:48:35 +0100

This paper proposes VehILux, a new vehicular mobility model based on real traffic counting data. It relies on two freely available sources of real information for the country of Luxembourg. The first source is traffic data collected by counting devices located on the Luxembourgian road network, while the second is geographical information about different types of areas: residential, industrial, commercial and other services. VehILux models vehicles commuting around the city of Luxembourg by considering two types of traffic, outer traffic with vehicles entering in the defined geographical area and inner traffic starting from residential zones located inside the geographical area. One part of the collected traffic data is used as input traffic, while another part is used to control the produced traffic and to fine-tune the model. VehILux is coupled with the microscopic road traffic simulator SUMO to produce realistic vehicular traces.

Models and applications of optimal transport in economics, traffic, and urban planning

Scipedia content — Mon, 25 Jan 2021 10:33:40 +0100

Some optimization or equilibrium problems involving somehow the concept of optimal transport are presented in these notes, mainly devoted to applications to economic and game theory settings. A variant model of transport, taking into account traffic congestion effects is the first topic, and it shows various links with Monge-Kantorovich theory and PDEs. Then, two models for urban planning are introduced. The last section is devoted to two problems from economics and their translation in the language of optimal transport.

Sensor Fusion and its Applications

Scipedia content — Mon, 25 Jan 2021 10:32:10 +0100

ATC is a critical area related with safety, requiring strict validation in real conditions (Kennedy & Gardner, 1998), being this a domain where the amount of data has gone under an exponential growth due to the increase in the number of passengers and flights. This has led to the need of automation processes in order to help the work of human operators (Wickens et al., 1998). These automation procedures can be basically divided into two different basic processes: the required online tracking of the aircraft (along with the decisions required according to this information) and the offline validation of that tracking process (which is usually separated into two sub-processes, segmentation (Guerrero & Garcia, 2008), covering the division of the initial data into a series of different segments, and reconstruction (Perez et al., 2006, Garcia et al., 2007), which covers the approximation with different models of the segments the trajectory was divided into). The reconstructed trajectories are used for the analysis and evaluation processes over the online tracking results. This validation assessment of ATC centers is done with recorded datasets (usually named opportunity traffic), used to reconstruct the necessary reference information. The reconstruction process transforms multi-sensor plots to a common coordinates frame and organizes data in trajectories of an individual aircraft. Then, for each trajectory, segments of different modes of flight (MOF) must be identified, each one corresponding to time intervals in which the aircraft is flying in a different type of motion. These segments are a valuable description of real data, providing information to analyze the behavior of target objects (where uniform motion flight and maneuvers are performed, magnitudes, durations, etc). The performance assessment of ATC multisensor/multitarget trackers require this reconstruction analysis based on available air data, in a domain usually named opportunity trajectory reconstruction (OTR), (Garcia et al., 2009). OTR consists in a batch process where all the available real data from all available sensors is used in order to obtain smoothed trajectories for all the individual aircrafts in the interest area. It requires accurate original-to-reconstructed trajectoryâs measurements association, bias estimation and correction to align all sensor measures, and also adaptive multisensor smoothing to obtain the final interpolated trajectory. It should be pointed out that it is an off-line batch processing potentially quite different to the usual real time data fusion systems used for ATC, due to the differences in the data processing order and its specific 2

Document type: Book

Development of a Time-Space Diagram to Assist Air Traffic Controllers in Monitoring Continuous Descent Approaches

Scipedia content — Mon, 25 Jan 2021 10:31:09 +0100

Link Capacity Dimensioning Model of ATS Ground Voice Network

Scipedia content — Mon, 25 Jan 2021 10:30:11 +0100

Modern communication networks have to be capable of responding to random fluctuations of requests and errors in different ways. One of them is traffic routing i.e. resource allocation. The designing of such networks (intelligent ones) and their management represent a challenge in mathematical, engineering and economic manner. This chapter describes the scheme of dynamic routing and the derived and presented model which is useful for dimensioning of initial link capacities as well as in the analysis of network stability. Emphasis is on the telephone network for G/G communication in ATM, for which the userÃ¢â¬â¢s requirements have been described together with the technical requirements that are necessary to support them. For the design of AGVN the usual methods of determining the telecommunication traffic are used. It should be emphasised, however, that there is a difference in relation to public telephone networks in that the calls in ATM are shorter and the recommended GoS value is lower (0.001). The chapter presents the necessary capacities for GoS value that is used in public networks and for the recommended GoS value for AGVN. The results show substantial savings in the number of channels. Since VCSs can distinguish the type of call and allocate priorities, for the dimensioning of the transmission link capacities a higher GoS value can be used, realizing at the same time a satisfactory Quality of Services for certain calls.

The use of rail transport as part of the supply chain in an urban logistics context

Scipedia content — Mon, 25 Jan 2021 10:02:29 +0100

Abstract: In Western Europe, the rail freight industry has been liberalized during recent years. The number of actors multiplies, the network connections of railroad and intermodal logistics companies grow and new actors enter the market. A directive called for separated accounting structures between the network provider and the operational activities. The right to privately operate, at first international and afterwards national freight trains came later. The liberalization had a major impact on the former state-owned monopolistic rail companies (the incumbents) and logistics actors calling at them. New market possibilities arose, but more actors now need to collaborate. This paper explores new logistics concepts in Western Europe, involving rail transport, now being in the trial - or investigation phase. This paper deals with the use of rail transport as part of the supply chain in an urban logistics context. The link will be made between two research subjects: the economic and ecologic viability of rail or intermodal transport, and the logistics capacity problems in an urban context, the latter of which is a growing research stream. First, a brief overview of the European railway market will be given. The difference between the European short-distance rail freight organization and American short-haul services will be described. Second, the concept of a new smart supply chain involving rail, developed by Deketele et al., will be given. The theory of the concept was put in to practice in Belgium by Procter and Gamble. This will be highlighted shortly. Afterwards, the concept of the modern supply chain involving rail will be compared to the actual supply chain of the French retail group Monoprix. The Monoprix supply chain will be discussed in the framework developed by Deketele et al. The actual French logistics bottlenecks, modal split, important legislation and outcomes will be treated. Results of the Monoprix supply chain will be given. Finally, conclusions will be drawn. Rail transport is hardly used in supply chains nowadays. In contrast, European governments set policy goals regarding non-road freight transport modes. Making the total supply chain more sustainable means decreasing road transport usage. Rail transport is being looked at as a solution for road traffic congestion problems. The modal share of rail transport in Europe declined the last decades to less than 15%. The authors assume that the results of this project, specifically highlighting best practices, can change the thinking pattern of supply chain executives.

The Kalman Filter in Power Quality – Theory and Applications

Scipedia content — Thu, 21 Jan 2021 15:35:26 +0100

Power quality is a topic in the area of engineering that emerged by the 1970 decade. It is a field that has attracted special interest recently due to the continuous industrial growth, to the raise of power demands, and to the proliferation of âpollutingâ electrical loads. One of the objectives of power quality is to meet a clean sinusoidal, stable, reliable, regulated, and uninterrupted supply voltage in electrical systems, in order to feed the so-called critical loads. A critical load is such an equipment that, if it fails or works inadequately, it can cause very high losses, being economical, or of any class; and a low quality supply can cause this situation. For example, it can cause the loss of vital information, interruption of an expensive industrial process, poor quality or damage to products; interruption of important communications as air traffic control, security units, and financial information; permanent damage to equipments, and even put lives in danger at hospitals. The great increment in critical processes has led to the requirement of assuring a high quality and safe power supply in many medical, communications, and industrial procedures, with the aim of feeding machinery and automatic systems that perform diverse important tasks. A safe protection of the operations is the objective. Problems and failures in electrical loads can be caused by some of the disturbances that exist in electrical systems. Among them are: harmonic distortion, unbalances, non characteristic harmonics, sags, swells, short and long interruptions, flicker, and short circuits. The disturbances that more affect critical loads, specially the industrial kind, are the sags, the swells, and the interruptions. The sag is defined as a 10% to 90% decrement of the nominal value of voltage, which can last from a half cycle to one minute. The swell is defined in a similar way, but represented by the 10% to 80% increase of the nominal value (IEEE Std 1159-1995, 1995), (IEEE Std 1159.3-2003, 2004). Sags have been identified as the most severe disturbance, and as the one that more causes damages and problems to facilities and equipments. It is considered that sags, together with momentary interruptions, are responsible of the 92% of power quality problems that face typical industrial consumers (Bhadkamkar et al., 2003). Sags can be caused by atmospheric discharges, short circuits, energizing of motors and high power loads, operation of soldering machines, and arc furnaces, to mention some. The swells can be caused by disconnections of high power loads from the grid. As can be noted, the disturbances can be generated by natural cause, by neighbor installations, or by accident. It is always desirable their

The port city in multidisciplinary analysis

Scipedia content — Thu, 21 Jan 2021 15:33:27 +0100

The inherent complexity of the port city has drawn attention from a vast number of scholars belonging to a variety of scientific fields. While a full and exhaustive review would reach beyond the scope of this chapter, it proposes evaluating the level of cohesion of port-city research through a classification of main study areas and their outcomes. Multiple definitions of the port city are both a cause and a consequence of the fragmentation of port-city research. There is a necessity refining the status of port-city research within mainstream approaches on either ports or cities.

A transition towards sustainable strategy making: integrating land use and transport knowledge types

Scipedia content — Thu, 21 Jan 2021 15:18:34 +0100

As extensively discussed by other scholars, there is a growing awareness that the integration of land use and transport (LUT) planning is a crucial prerequisite for the transition towards more sustainable transport patterns and urban development that foster interaction between people, support a sustainable business climate and reduces negative effects on the environment and climate (see, for example, Banister 2002, 2005; Cervero 1998; Meyer and Miller 2001; TRB 2004). However, in the Netherlands (and in other countries), such integration is scarcely present in daily planning practice (see, for instance, Hull and Tricker 2006). If anything, one can speak of policy coordination rather than âintegrationâ; i.e. it is dialogue or information exchange which is geared at avoiding conflicts between projects, but does not seek to establish similar policy goals (Stead et al. 2004). Achieving integration in earlier phases of planning (for example, strategy development, goal orientation or visioning) can potentially produce shared policy goals, which would promote mutually reinforcing (instead of obstructing) land use and transport measures. However, for this to happen, a transition on its own is needed.

Optical Metropolitan Networks: Packet Format, MAC Protocols and Quality of Service

Scipedia content — Thu, 21 Jan 2021 15:04:35 +0100

International audience; Optical Packet Switching (OPS) is among the most promising solutions for next generation metropolitan networks. The increase of packet-based services (video on demand, etc.) is pushing metropolitan networks providers to renew their infrastructures. Today, metropolitan networks are based on SONET/SDH circuit-switched networks, which are becoming inefficient and costly to support new requirements of quality of service and bandwidth of sporadic packet-based traffic. To solve this problem, many new network solutions are proposed recently, including Next Generation SONET/SDH, Resilient Packet Ring, etc. Among others, the optical networking technology appears a good choice thanks to its following benefits: huge transmission capacity, high reliability, and high availability. This paper is devoted to provide an overview of the metropolitan network infrastructure and particularly to its evolution towards OPS networks. It also highlights performance issues in terms of optical packet format, medium access control protocol and quality of service, as well as traffic engineering issue

Welfare Tradeoffs in U.S. Rail Mergers

Scipedia content — Thu, 21 Jan 2021 14:54:18 +0100

The renegotiation of regulatory contracts is known to prevent regulators from achieving the full commitment efficient outcome in dynamic contexts. However, assessing the cost of such renegotiation remains an open issue from an empirical viewpoint. To address this question, we fit a structural principal-agent model with renegotiation on a set of urban transport service contracts. The model captures two important features of the industry. First, only two types of contracts are used in practice (fixed-price and cost-plus). Second, subsidies increase over time. We compare a scenario with renegotiation and a hypothetical situation with full commitment. We conclude that the welfare gains from improving commitment would be significant but would accrue mostly to operators.

Auf dem Weg zu einem Grundangebot von Mobilität in ländlichen Räumen: Probleme, Ursachen und Handlungsoptionen

Scipedia content — Thu, 21 Jan 2021 14:26:42 +0100

Der Beitrag geht der Frage nach, wie in lÃ¤ndlichen RÃ¤umen ein Grundangebot von MobilitÃ¤t gewÃ¤hrleistet bzw. hergestellt werden kann. Dazu werden zunÃ¤chst die Besonderheiten der MobilitÃ¤t in lÃ¤ndlichen RÃ¤umen im Vergleich zu urbanen Gebieten herausgearbeitet sowie aktuelle Trends, Probleme und Konsequenzen fÃ¼r das ÃPNV-Angebot beleuchtet. SchlieÃlich werden verschiedene Handlungsoptionen vorgestellt, wie mit diesen Entwicklungen umgegangen werden kann, um ein Grundangebot sicherstellen zu kÃ¶nnen. Dabei werden hÃ¤ufig bedarfsgesteuerte Bedienformen als LÃ¶sung angepriesen. Die Analyse zeigt jedoch, dass insbesondere in dÃ¼nn besiedelten lÃ¤ndlichen RÃ¤umen erhebliche Finanzierungsdefizite zu erwarten sind. Deshalb werden weitere Alternativen, wie die Effizienzsteigerung im traditionellen ÃPNV, BÃ¼rgerbusse, organisierte Mitnahme im privaten Pkw, mobile und dezentrale Versorgung mit Dienstleistungen, Mitnahme durch andere Fahrdienste, Carsharing und SubjektfÃ¶rderung im ÃPNV diskutiert. Im Ergebnis zeigt sich, dass alle Handlungsoptionen sowohl Vor- als auch Nachteile aufweisen. Diese Vielfalt an Bedienformen kann jedoch dazu genutzt werden, das Angebot auf die spezifischen Bedingungen vor Ort zuzuschneiden, was zu einem abgestuften System von den Zentren zur Peripherie fÃ¼hrt. The paper addresses the question how a basic provision of mobility could be assured in rural areas. To answer the research question, it analyses the particularities of rural mobility in comparison to urban areas, current trends and resulting problems for the public transport. Afterwards, the review presents different options for action to guarantee a basic mobility against these issues. In transport policy debates, demand responsive transport is often seen as a solution. However, many studies demonstrate the low potential of this transport service, mainly due to the low revenue-to-cost ratio of such services. Therefore, the paper discusses further alternatives including raising efficiency in traditional public transport, voluntary public transport, ride sharing in private cars or in cars of other transport services, mobile and decentral supply of services, car sharing and disbursing mobility vouchers. As a result, all researched alternatives have their particular strengths and weaknesses. The variety of mobility options can, thus, contribute to a tailor- made transport policy considering the specific local conditions. The conclusion comprises a gradual mobility system from core to periphery.

Document type: Book

On-Board Monocular Vision System Pose Estimation through a Dense Optical Flow

Scipedia content — Thu, 21 Jan 2021 14:17:43 +0100

This paper presents a robust technique for estimating on-board monocular vision system pose. The proposed approach is based on a dense optical flow that is robust against shadows, reflections and illumination changes. A RANSAC based scheme is used to cope with the outliers in the optical flow. The proposed technique is intended to be used in driver assistance systems for applications such as obstacle or pedestrian detection. Experimental results on different scenarios, both from synthetic and real sequences, shows usefulness of the proposed approach.

The Cost of Contract Renegotiation: Evidence from the Local Public Sector

Scipedia content — Thu, 21 Jan 2021 13:51:49 +0100

Economic theory claims that contracts renegotiation prevents from reaching the informationally constrained efficient solution that could have been obtained under full commitment. Assessing the cost of renegotiation compared to the full commitment scenario still remains an open issue from an empirical viewpoint. To address this question, we fit a structural principal-agent model with renegotiation on a set of contracts for urban transport services. The model captures two important features of the industry. First, only two types of contracts are used in practice (fixed-price and cost-plus). Second, subsidies are greater when a cost-plus contract was signed earlier on than following a fixed-price contract. We then compare a scenario with renegotiation and a hypothetical situation with full commitment. We conclude that the welfare gains from improving commitment would be significant but would accrue mostly to operators.

Document type: Preprint

Implementation of Adaptive Control for P2P Overlays

Scipedia content — Thu, 21 Jan 2021 13:50:42 +0100

Peer-to-peer networking enjoys euphoric support and fierce resistance simultaneously, and for the same reasons. It presents a model where decentralization and lack of structure, hierarchy and control are promoted. Although significant research is carried out to tackle individual issues arising from that paradigm, there has been no obvious approach for evening out differences on a more general basis. In this paper we introduce a framework and provide implementation techniques for such an approach. The framework aims at integrating partial techniques that solve individual problems and has been designed for flexibility. The integrated approach we are proposing includes forming and maintaining of peer-to-peer overlays, controlling the underlying topology being formed, limiting the signaling traffic being generated and optimizing the payload traffic.

Spatial, Temporal, and Hybrid Decompositions for Large-Scale Vehicle Routing with Time Windows

Scipedia content — Thu, 21 Jan 2021 13:49:56 +0100

This paper studies the use of decomposition techniques to quickly find high-quality solutions to large-scale vehicle routing problems with time windows. It considers an adaptive decomposition scheme which iteratively decouples a routing problem based on the current solution. Earlier work considered vehicle-based decompositions that partitions the vehicles across the subproblems. The subproblems can then be optimized independently and merged easily. This paper argues that vehicle-based decompositions, although very effective on various problem classes also have limitations. In particular, they do not accommodate temporal decompositions and may produce spatial decompositions that are not focused enough. This paper then proposes customer-based decompositions which generalize vehicle-based decouplings and allows for focused spatial and temporal decompositions. Experimental results on class R2 of the extended Solomon benchmarks demonstrates the benefits of the customer-based adaptive decomposition scheme and its spatial, temporal, and hybrid instantiations. In particular, they show that customer-based decompositions bring significant benefits over large neighborhood search in contrast to vehicle-based decompositions.

Legal Aspects of Air Traffic Management Based on Satellite Navigation

Scipedia content — Thu, 21 Jan 2021 13:46:52 +0100

According to IEEExxviii definition interoperability is the ability of two or more systems or components to exchange information and to use the information that has been exchanged. In GNSS context ,interoperability can be understood such that individual GNSS components should be designed ,built and operated in such a way that they do not Ã¢â¬ËjamÃ¢â¬â¢ each other and allow one to combine their signal in a navigation service of superior quality.ICG (International Committee on Global Navigation Satellite System) is a forum established on a voluntary basis as a informal body to promote cooperation, as appropriate ,on matters of mutual interest related to civil satellite based positioning, navigation ,timing and value added services, as well as the compatability and interoperability of global navigation satellite system while increasing their use to sustainable development. Within the ICG is the providers forum, consisting of those countries operating GNSS system or with plans to develop one .Providers forum adopted Definition of interoperability as follows Ã¢â¬ËInteroperability refers to the ability of global and regional navigation satellite systems and augmentations and service they provide to be used together to provide better capabilities at user level than would be achieved by relying solely on the open signal systemÃ¢â¬â¢ Interoperability of GNSS poses innumerable issues to end user with regard to claim and jurisdictionxxix. .Certainly interoperability signifies involvement of multiple GNSS providers located indifferent jurisdiction having conflicting domestic laws. The task of claimant in such context is to identify appropriate jurisdiction and law applicable for such claim.

Barcelona clean energy tour

Scipedia content — Thu, 21 Jan 2021 13:22:43 +0100

Performance of Multicast Packet Aggregation in All Optical Slotted Networks

Scipedia content — Thu, 21 Jan 2021 13:17:08 +0100

The study focuses on packet aggregation mechanisms on the edge router of an optical network. The device works as an interface between the electronic and optical domains : it takes IP packets coming from client layers and converts them into optical packets to be sent into the optical network. An efficient aggregation mechanism supporting QoS (Quality of Service) requirements of IP flows is presented. A timer is implemented to limit the aggregation delay. Analytical models based on Markov chains are presented in order to study the packetisation efficiency (filling ratio) and the mean time of packetisation for each class. Numerical results show the effect of IP packet lengths distribution on aggregation delay and efficiency. Also, we show the importance of the timer in bounding the delay of transmitted packets without much altering the aggregation efficiency.

Benefit measures for noise abatement: calculations for road and rail traffic noise

Scipedia content — Thu, 21 Jan 2021 13:15:24 +0100

Purpose : the aim of this study is to estimate monetary abatement values for road and rail traffic noise that can be used for policy purposes. However, a main objective is to critically discuss the assumptions necessary to convert the monetary values elicited in willingness to pay (WTP) studies to values than can be use for policy purposes. Methods : we employ the hedonic regression technique on Swedish data to elicit individualsâ preferences for noise abatement. Our elicited values are then converted to policy values and critically examined based on findings from a literature review. Results : we show that WTP for road and rail not only differs in levels but also that the relationship between the noise level and the marginal value differs between the two sources. We also show that a health cost component added to the WTP estimate, based on the assumption of uninformed property buyers, will be small but not negligible and that also modest differences in the assumption of the discount rates will have a significant effect on the estimated values. Conclusions : the main implications from this study are: (i) WTP for road and railway noise abatement differs not only on absolute but also marginal levels, (ii) Even small differences in the chosen discount rate, which is necessary to convert WTP values from a hedonic price study to policy values, have large effects on the policy values, and (iii) We show how to add a health cost component to the WTP estimates in order for the monetary estimates to reflect the total social cost. However, we argue that the motivation for doing so is weak and that more research is needed on this issue.

Document type: Preprint