- Self-Organization in Large Populations of Mobile Robots - A homogeneous population of robots described as an Army-ant swarm is to be realized for material transportation. Robots envisioned in the Army-ant scenario are relatively small, independent autonomous mobile robots which can cooperatively carry palletized loads. In this thesis, the agents are treated as a self-organizing system of moving points. This characteristic makes the Army-ant swarm a modular, adaptive and dynamic system.
Several algorithms for spatial self-organization of the robots are given. Self-organizing agents can arrange themselves geometrically in two- and three-dimensional space using only local information about teammates. The method is a distributed one: each agent uses only the information obtained by its own sensors. Algorithms are based on feasible assumptions. It is also shown possible to divide such a population into different groups around goals by communicating minimal data. Data transfer has a broadcast characteristic.
Behavioral self-organization in the Army-ant scenario is also investigated. Activation and inhibition relations between robots determine the behavior (position in a behavioral space) of the agents, while in spatial self-organization force fields are in effect.
Several problems which may be encountered and the solution to some of these problems are outlined. Methods for communication and cooperative decision systems - such as coupled van der Pol oscillators - in finding and carrying the pallets are proposed. Sensors and communication systems which may be used in the Army-ant scenario are also briefly discussed.
- Using GIS to Model and Visualize Congestion Effects on Individual Accessibility - Considerable attention has been devoted to the measurement of accessibility to employment, shopping, educational opportunities, health care facilities, and other services within cities. The use of Geographic Information Systems has enormous utility for such research because of its ability to not only represent the components of the urban environment, such as the home locations of individuals, employment opportunities and retail or other service locations, but also for modeling the spatial relationships among these components through the use of computationally intensive transport network analysis methods. The value of Geographic Information Systems is especially apparent with the use of disaggregate space-time accessibility measures because of their requirement for a very high degree of temporal and spatial resolution of the urban environment, and especially of the accurate representation of the movement possibilities of individuals through urban networks. While considerable attention has been directed at the representation of the urban environment it is argued here that accessibility research has not yet taken full advantage of the network analytical capabilities available within Geographic Information Systems. Instead, even when detailed representations of networks are used, potentially unrealistic measures of travel time based on assumptions about constant travel speeds through the network may be incorporated within studies. It can be argued that doing so creates limitations for accessibility measures as utilizing a single travel time for all hours of the day does not allow for the existence of daily congestion or hourly variations in traffic volumes. Applying a constant travel time to all areas of a city also does not allow for highly localized congestion within transport networks so that traffic flows and the effects of peak hour congestion are uniform throughout the entire urban area. The ability to incorporate spatially and temporally specific traffic congestion is therefore likely to offer considerable insight and detail into individual accessibility. This research seeks to show how these limitations can be overcome by measuring accessibility using space-time concepts with a detailed street network for the Portland, Oregon, metropolitan area, using spatially and temporally varying estimates of highway travel times. Further, because the measurement of accessibility is based on actual travel diary with trip data for 200 individuals, it is possible to incorporate the locations and times of day during which travel took place for each individual. The resulting accessibility values therefore reflect not only each individual's daily activity patterns and constraints, the opportunities available to them in different locations of the city, but also the uneven spatial and temporal effects of congestion. These effects can be visualized by the use of network potential path areas to show the areas and potential activity opportunities which individuals would be able to reach during their travel, both with and without congestion effects. The use of standard ArcView GIS is fundamental to this application because of its network analytical abilities and the need to incorporate the spatial relationships existing between streets, activity locations, and activity opportunities contained in multiple data sets.
- Car Sharing Autoshare Car Sharing Network: Car Sharing in Toronto, AutoShare Carsharing; AutoShare Car Sharing, Auto Share
- STOMPM (STrike Optimized Mission Planning Module) - STOMPM is able to exploit the highest resolution terrain data to automatically determine optimal routes for ground and air platforms, as well as determining vulnerability to enemy ground and air assets. The sheer volume of data in many cases would prohibit any but the crudest attempts to manually determine such routes. Unlike any other existing automated routing system, STOMPM optimally incorporates turn radius and fuel constraints. Other systems that enforce these constraints using heuristic approaches can produce extremely poor routes or even fail to find a feasible route when one exists. Although STOMPM began as an experimental testbed for sophisticated routing and optimization algorithms, it is rapidly evolving into a mature system. In combination with NRL's Virtual Workbench, STOMPM represents the most powerful tool for computing and visualizing high fidelity routes.
- Transportation Links
- The Wired Car in the Wired World - As the news about new technology goes by in its daily doses, it's easy to lose track of the patterns. So let us take a moment and connect some dots. Let us take a single, familiar site -- the car -- and trace the amazing variety of institutions that intend to wire that site in one way or another. Most of us, especially if we are Americans, drive a car all the time, and we recognize that the car is a point of intersection for many institutional agendas. At any given time, most of us have at
least one bureaucratic hassle in progress relating to our cars, be it buying, selling, registration, repair, insurance, law enforcement, parking, you name it. Every one of those hassles is organized by an institution, and every institution has more or less the same components: several layers of law, a sprawling map of interested parties, an information
infrastructure, nonobvious interactions between governments and markets, people who specialize in working all of the
angles, and a culture of popular resistance and vigilantism.
- Converging Technologies - The convergence of computing and telecommunications technologies is dramatically changing the face of today's business world. As the cost of exchanging information is driven down with each new advance in technology, traditional, vertically integrated companies are giving way to more flexible organizations whose market-based relationships allow them to respond quickly and efficiently to the ever-changing demands and needs of consumers. Recently, Stick and Carrot spoke with Phil Hood, an analyst with Toronto-based Alliance for Converging Technologies, on how converging technologies are revolutionizing the way organizations work in the marketplace.
- Deepening Incorporation: The Spatial Organization Of Trade And Class Struggle Over Transport Infrastructure: Southern Appalachia, 1830-1860 - Inland from the Atlantic coast of North America rise the Appalachian mountains. This region has been stereotyped as a "subsistent region of refuge" that remained resistant to capitalist development until the early twentieth century. Rugged terrain and the lack of roads supposedly deterred external trade, prevented the growth of an export economy, and slowed the development of capitalist enterprises (Eller 1982). My own revisionist research has now attacked that historiography. In reality, Southern Appalachia was absorbed into the capitalist world-system as part of the extended Caribbean, that vast New World region stretching from Brazil to present-day Maryland. During the global expansion cycle of 1672-1700, Southern Appalachia was incorporated as a peripheral fringe of the European colonies located along the southeastern coasts of North America. Southern Appalachia was, in fact, one of the major frontier arenas in which England, France, and Spain played out their hegemonic imperialism for core status. Blocking easy expansion into the Ohio and Mississippi valleys was that vast mountain range stretching from present-day western Maryland and West Virginia to northern Alabama. The first stage of capitalist incorporation occurred in the eighteenth century with the integration of Southern Appalachia's indigenous Cherokees into the international fur trade (Dunaway 1994). After the American Revolution, settler capitalists continued the transformation of Southern Appalachia into the first frontier-periphery located within the newly-formed United States. This research focuses on that second historical era of deepening incorporation by investigating these five questions:
- What was the role of Southern Appalachia in the in the capitalist world-economy?
- Through what transport systems was this mountainous terrain articulated with global commodity chains?
- Who were the Appalachian agents who organized the flow of commodities from and into this mountainous periphery?
- How did class conflict over transport infrastructure deepen capitalist inequalities in the region?
- How did transport lag deepen the peripheralization of this region?
- Transportation and the Economy - As noted in the President's Technology for America's Economic Growth, A New Direction to Build Economic Strength, a competitive, growing economy requires a transportation system that can move people, goods, and services quickly and efficiently. To meet this challenge, each transport sector must work effectively both by itself and as part of a larger, interconnected whole. Technologies that increase the speed, reliability, and cost-effectiveness of the transportation sector also will increase the economy's competitiveness and ability to create jobs. Today, one of the greatest challenges we face is to rehabilitate and properly maintain the huge stock of infrastructure facilities already in place. Providing a world-class transportation sector will require the Nation to meet the challenges posed both by increased congestion in many parts of the transportation system and by the need to rebuild and maintain a public capital stock valued at more than $2.4 trillion. The Federal Government is committed to leading an effort to realize the vision of "sustainable" transportation, with the goal of balancing different modes of transportation while taking into account performance, cost, resource use, and social impact.
- Transportation, Land Use and Resource Management - Digital Infrastructure Report - What is the impact of the digital network infrastructure on transportation, land use, and resource management? We are all dependent upon these systems to undergird the region's commerce and our daily lives. The availability and use of roads and bridges, public transit and communication lines, property, air and water, sewers and waste disposal are all determined through public policies that have been developed over several centuries. However, the impacts of the digital network infrastructure on these systems are not entirely obvious. Yet, although the digital network is invisible, its impacts on transportation, land use, and resource management are likely to be quite profound.
- Looking Down the Road: Transport Informatics and the New Landscape of Privacy Issues - Two technologies, computer networking and public-key cryptography, have transformed the landscape of technology-and-privacy issues. This article illustrates the changes and explores their consequences by describing the emerging privacy issues surrounding transport informatics, primarily in the United States. Transport informatics is a European term for the use of information and communication technologies in transportation. It encompasses a wide variety of activities whose underlying unity is not always obvious. The largest institutional focus for transport informatics research and development in the United States has been the Intelligent Vehicle-Highway Systems (IVHS) program of the US Department of Transportation (DoT), whose industrial partners have recently switched to the more general term Intelligent Transportation Systems (ITS) in order to include a broader range of surface transportation modalities -- especially city streets. This program aims to define a common architecture for the many state and private transport informatics initiatives.
- Redefining Progress - Despite seemingly expensive gas prices, drivers pay less than half of the costs created by the use of their automobiles when the total costs of driving - including increased congestion, space covered by pavement, accidents, and pollution - are considered. A Redefining Progress issue brief released today explains how everyone (non-drivers, taxpayers, and other drivers) pays every time a driver gets behind the wheel.
- Transport Geography - first rate instructional site including practical exercises - Welcome to the transport geography web site, a project developed by a consortium of five Universities to promote access to transport geography information on the Internet. It includes material to support an undergraduate course in transport geography, but it can also be used for lectures in economic, urban and regional geography.
- Online TDM Encyclopedia: Index - Transportation Demand Management (TDM) is the general term for actions that encourage more efficient use of existing transportation systems. It includes a wide range of specific strategies. This Encyclopedia is designed to be a primary source of information about TDM. It provides detailed information on more than three dozen specific TDM strategies.
- A Note on Commutes and the Spatial Mismatch Hypothesis - A number of empirical studies have tested the spatial mismatch hypothesis by examining the commuting times of blacks and whites. This note points out that the link between spatial mismatch and commuting times may be weak when employment probabilities decline as the distance from job site to residence increases. A simple spatial model of urban employment is developed in which a fixed number of agents live in the central city. Two examples are presented in which increased spatial mismatch may either increase or decrease the average commuting time of central city minorities, depending on the rate at which employment probabilities decline with distance.
- Towards a percolation model of accessibility - Transportation networks are characterized by two complementary functions: accessibility to economic activities and mobility to carry out these activities. One of the ways to measure accessibility is the number of opportunities available to a user of a transportation network. For users to carry out economic activities, i.e., exercise mobility, they have to at least have conceptual or perceived links to the activities. Given this, we ask what is the process that leads to the development of these perceived links? We present an analytical approach based on percolation theory to explain the evolution of perceived links to economic activities. A subjective accessibility measure, i.e., a network of perceived links, is developed based on economic opportunities and individual's income levels in a transport region.
- National Transportation Library (USDOT) - Transportation bibliography. Covers material from the 1960s to present. In all some 400,000 bibliographic records with abstracts (yearly addition 20,000).
- Innovative Transportation Technologies main index page
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- Asphalt Nation: How the Automobile Took Over
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- Geospatial Data for ITS (Intelligent Transportation Systems)
- The Impact Of Highway Infrastructure On Economic Performance
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- Some Information Technologies in the Express Parcel Industry
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