257 research outputs found
More Market-Oriented Than the United States and More Socialist Than China: A Comparative Public Property Story of Singapore
Compared to the more illustrious conceptualization of private property, the conceptualization of public property remains at a surprisingly infantile stage. The very definition of public property is ambiguous. This article utilizes a comparative case study of traffic congestion policies in the United States, China, and Singapore to highlight the conceptual pitfalls posed by the current confusion on public property. This article proposes a refined public property framework that offers greater conceptual clarity on the real issues at stake. In particular, this article argues that “property” in public property should include regulatory permits while “public” in public property should not be distracted by the requirement of public access. The allocation considerations of efficiency and fairness governing conventional public property are equally applicable to economically valuable regulatory permits. Similarly, public access is a mere form of allocation that should be changed upon alterations in use pattern arising from technological advancement and socioeconomic changes
The Multi-Agent Transport Simulation MATSim
"The MATSim (Multi-Agent Transport Simulation) software project was started around 2006 with the goal of generating traffic and congestion patterns by following individual synthetic travelers through their daily or weekly activity programme. It has since then evolved from a collection of stand-alone C++ programs to an integrated Java-based framework which is publicly hosted, open-source available, automatically regression tested. It is currently used by about 40 groups throughout the world. This book takes stock of the current status. The first part of the book gives an introduction to the most important concepts, with the intention of enabling a potential user to set up and run basic simulations.The second part of the book describes how the basic functionality can be extended, for example by adding schedule-based public transit, electric or autonomous cars, paratransit, or within-day replanning. For each extension, the text provides pointers to the additional documentation and to the code base. It is also discussed how people with appropriate Java programming skills can write their own extensions, and plug them into the MATSim core.
The project has started from the basic idea that traffic is a consequence of human behavior, and thus humans and their behavior should be the starting point of all modelling, and with the intuition that when simulations with 100 million particles are possible in computational physics, then behavior-oriented simulations with 10 million travelers should be possible in travel behavior research. The initial implementations thus combined concepts from computational physics and complex adaptive systems with concepts from travel behavior research. The third part of the book looks at theoretical concepts that are able to describe important aspects of the simulation system; for example, under certain conditions the code becomes a Monte Carlo engine sampling from a discrete choice model. Another important aspect is the interpretation of the MATSim score as utility in the microeconomic sense, opening up a connection to benefit cost analysis.
Finally, the book collects use cases as they have been undertaken with MATSim. All current users of MATSim were invited to submit their work, and many followed with sometimes crisp and short and sometimes longer contributions, always with pointers to additional references.
We hope that the book will become an invitation to explore, to build and to extend agent-based modeling of travel behavior from the stable and well tested core of MATSim documented here.
A Data-driven Methodology Towards Mobility- and Traffic-related Big Spatiotemporal Data Frameworks
Human population is increasing at unprecedented rates, particularly in urban areas. This increase, along with the rise of a more economically empowered middle class, brings new and complex challenges to the mobility of people within urban areas. To tackle such challenges, transportation and mobility authorities and operators are trying to adopt innovative Big Data-driven Mobility- and Traffic-related solutions. Such solutions will help decision-making processes that aim to ease the load on an already overloaded transport infrastructure. The information collected from day-to-day mobility and traffic can help to mitigate some of such mobility challenges in urban areas.
Road infrastructure and traffic management operators (RITMOs) face several limitations to effectively extract value from the exponentially growing volumes of mobility- and traffic-related Big Spatiotemporal Data (MobiTrafficBD) that are being acquired and gathered. Research about the topics of Big Data, Spatiotemporal Data and specially MobiTrafficBD is scattered, and existing literature does not offer a concrete, common methodological approach to setup, configure, deploy and use a complete Big Data-based framework to manage the lifecycle of mobility-related spatiotemporal data, mainly focused on geo-referenced time series (GRTS) and spatiotemporal events (ST Events), extract value from it and support decision-making
processes of RITMOs.
This doctoral thesis proposes a data-driven, prescriptive methodological approach towards the design, development and deployment of MobiTrafficBD Frameworks focused on GRTS and ST Events. Besides a thorough literature review on Spatiotemporal Data, Big Data and the merging of these two fields through MobiTraffiBD, the methodological approach comprises a set of general characteristics, technical requirements, logical components, data flows and technological infrastructure models, as well as guidelines and best practices that aim to guide researchers, practitioners and stakeholders, such as RITMOs, throughout the design, development and deployment phases of any MobiTrafficBD Framework.
This work is intended to be a supporting methodological guide, based on widely used
Reference Architectures and guidelines for Big Data, but enriched with inherent characteristics
and concerns brought about by Big Spatiotemporal Data, such as in the case of GRTS and ST
Events. The proposed methodology was evaluated and demonstrated in various real-world
use cases that deployed MobiTrafficBD-based Data Management, Processing, Analytics and
Visualisation methods, tools and technologies, under the umbrella of several research projects
funded by the European Commission and the Portuguese Government.A população humana cresce a um ritmo sem precedentes, particularmente nas áreas urbanas.
Este aumento, aliado ao robustecimento de uma classe média com maior poder económico,
introduzem novos e complexos desafios na mobilidade de pessoas em áreas urbanas. Para
abordar estes desafios, autoridades e operadores de transportes e mobilidade estão a adotar
soluções inovadoras no domínio dos sistemas de Dados em Larga Escala nos domínios da
Mobilidade e Tráfego. Estas soluções irão apoiar os processos de decisão com o intuito de libertar uma infraestrutura de estradas e transportes já sobrecarregada. A informação colecionada da mobilidade diária e da utilização da infraestrutura de estradas pode ajudar na mitigação de alguns dos desafios da mobilidade urbana.
Os operadores de gestão de trânsito e de infraestruturas de estradas (em inglês, road infrastructure and traffic management operators — RITMOs) estão limitados no que toca a extrair valor de um sempre crescente volume de Dados Espaciotemporais em Larga Escala no domínio da Mobilidade e Tráfego (em inglês, Mobility- and Traffic-related Big Spatiotemporal Data —MobiTrafficBD) que estão a ser colecionados e recolhidos. Os trabalhos de investigação sobre os tópicos de Big Data, Dados Espaciotemporais e, especialmente, de MobiTrafficBD, estão dispersos, e a literatura existente não oferece uma metodologia comum e concreta para preparar, configurar, implementar e usar uma plataforma (framework) baseada em tecnologias Big Data para gerir o ciclo de vida de dados espaciotemporais em larga escala, com ênfase nas série temporais georreferenciadas (em inglês, geo-referenced time series — GRTS) e eventos espacio-
temporais (em inglês, spatiotemporal events — ST Events), extrair valor destes dados e apoiar os
RITMOs nos seus processos de decisão.
Esta dissertação doutoral propõe uma metodologia prescritiva orientada a dados, para o design, desenvolvimento e implementação de plataformas de MobiTrafficBD, focadas em GRTS e ST Events. Além de uma revisão de literatura completa nas áreas de Dados Espaciotemporais, Big Data e na junção destas áreas através do conceito de MobiTrafficBD, a metodologia proposta contem um conjunto de características gerais, requisitos técnicos, componentes lógicos, fluxos de dados e modelos de infraestrutura tecnológica, bem como diretrizes e boas
práticas para investigadores, profissionais e outras partes interessadas, como RITMOs, com o
objetivo de guiá-los pelas fases de design, desenvolvimento e implementação de qualquer pla-
taforma MobiTrafficBD.
Este trabalho deve ser visto como um guia metodológico de suporte, baseado em Arqui-
teturas de Referência e diretrizes amplamente utilizadas, mas enriquecido com as característi-
cas e assuntos implícitos relacionados com Dados Espaciotemporais em Larga Escala, como
no caso de GRTS e ST Events. A metodologia proposta foi avaliada e demonstrada em vários
cenários reais no âmbito de projetos de investigação financiados pela Comissão Europeia e
pelo Governo português, nos quais foram implementados métodos, ferramentas e tecnologias
nas áreas de Gestão de Dados, Processamento de Dados e Ciência e Visualização de Dados em
plataformas MobiTrafficB
Future Transportation
Greenhouse gas (GHG) emissions associated with transportation activities account for approximately 20 percent of all carbon dioxide (co2) emissions globally, making the transportation sector a major contributor to the current global warming. This book focuses on the latest advances in technologies aiming at the sustainable future transportation of people and goods. A reduction in burning fossil fuel and technological transitions are the main approaches toward sustainable future transportation. Particular attention is given to automobile technological transitions, bike sharing systems, supply chain digitalization, and transport performance monitoring and optimization, among others
Queuing analysis at toll stations under the toll-free policy in holidays in Shanghai
In order to stimulate the holiday economy and ensure smooth travel, the Chinese government decided to exempt the tolls of small passenger cars on major holidays since the National Day on October 1st, 2012. Taking a toll station in Shanghai as a case study, this paper analyzed its queuing situation on the first day of Tomb-sweeping day holiday before and after the toll-free policy with a queuing theory model. How to balance the induced traffic and the limited highway capacity with optimal toll strategies was also discussed. The results show that with total departure traffic volume increasing and an average service time decreasing, the average queue length and congestion duration became longer for the first year after the implementation of the policy. But then queuing situations were improved markedly in later years with increasing percentage of ETC users. The conclusions may benefit policy makers for transition process of different toll strategies around the world
Price Regulation and Economic Growth in China
What is the causal effect of price regulation on economic growth? It is an unsolved problem for empirical research in economics, as most price regulation policies are endogenous to the economic performance. This thesis provides the first (causally identified) empirical analysis of the effect of price regulation on economic growth. I successfully identify a perfectly exogenous variable-the regulatory price of fuel in China. There are several factors contributing to the exogeneity of regulatory price, such as, provincial and city's geography, the highly centralized pricing mechanism, belated response from central government, and complex activation conditions on regulatory price adjustment. I construct a unique panel dataset of 289 prefecture cities from 1998 through 2018. It is the first time that the existence and prevalence of overcharging behaviors-petrol stations setting sales price higher than regulatory price-are clearly documented in the dataset.
This thesis answers the research question from both theoretical and empirical aspects. My macroeconometric analysis builds on solid microeconomic foundation-aggregate Marshallian surplus increases as binding regulatory price increases. As the underlying assumption of classical partial equilibrium model is that the sales price cannot exceed the regulatory price, I develop a simple model to feature the overcharging behaviors. The model predicts that the marginal total surplus of regulatory price is still positive if the risk of violating price regulation is not too large to deter the sellers from overcharging consumers. I estimate the causal effect via both time series and panel data techniques. First, by constructing a complete quarterly dataset on macroeconomic aggregates and using VAR model, I show that GDP responses significantly and positively to the regulatory price. Further analysis reveals that the changes of regulatory price have asymmetric effects on GDP; that is, GDP responses significantly to a smaller downward adjustment rather than a larger upward adjustment. Second, I use fixed effect model to find that 1% increase in regulatory price causes 2.69% increase in GRP (gross regional product). I also find that GRP responses more to the binding regulatory price than to the non-binding. Finally, by employing panel VAR model, I show the dynamic and permanent effects of regulatory price on regional economic growth
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Modeling and Optimizing Routing Decisions for Travelers and On-demand Service Providers
This thesis investigates the dynamic routing decisions for individual travelers and on-demand service providers (e.g., regular taxis, Uber, Lyft, etc).
For individual travelers, this thesis models and predicts route choice at two time-scales: the day-to-day and within-day. For day-to-day route choice, methodological development and empirical evidences are presented to understand the roles of learning, inertia and real-time travel information on route choices in a highly disrupted network based on data from a laboratory competitive route choice game. The learning of routing policies instead of simple paths is modeled when real-time travel information is available, where a routing policy is defined as a contingency plan that maps realized traffic conditions to path choices. Using data from a competitive laboratory experiment, prediction performance is then measured in terms of both one-step and full trajectory predictions. For within day route choice, a recursive logit model is formulated in a stochastic time-dependent (STD) network without sampling any choice sets. A decomposition algorithm is then proposed so that the model can be estimated in reasonable time. Estimation and prediction results of the proposed model are presented using a data set collected from a subnetwork of Stockholm, Sweden.
Taxis and ride-sourcing vehicles play an important role in providing on-demand mobility in an urban transportation system. Unlike individual travelers, they do not have a clear destination when there\u27s no passenger on board. The optimal routing of a vacant taxi is formulated as a Markov Decision Process (MDP) problem to maximize long-term profit over the full working period. Two approaches are proposed to solve the problem. One is the model-based approach where a model of the state transitions of the environment is obtained from queuing-theory based passenger arrival and competing taxi distribution processes. An enhanced value iteration for solving the MDP problem is then proposed making use of efficient matrix operations. The other is the model-free Reinforcement Learning (RL) approach, which learns the best policy directly from observed trajectory data. Both approaches are implemented and tested in a mega city transportation network with reasonable running time, and a systematic comparison of the two approaches is also provided
Sustainable Mobility and Transport
This Special Issue is dedicated to sustainable mobility and transport, with a special focus on technological advancements. Global transport systems are significant sources of air, land, and water emissions. A key motivator for this Special Issue was the diversity and complexity of mitigating transport emissions and industry adaptions towards increasingly stricter regulation. Originally, the Special Issue called for papers devoted to all forms of mobility and transports. The papers published in this Special Issue cover a wide range of topics, aiming to increase understanding of the impacts and effects of mobility and transport in working towards sustainability, where most studies place technological innovations at the heart of the matter. The goal of the Special Issue is to present research that focuses, on the one hand, on the challenges and obstacles on a system-level decision making of clean mobility, and on the other, on indirect effects caused by these changes
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