1,720,980 research outputs found
Development of an Integrated Simulation Package for Freeway Design, Operations and Adaptive Traffic Management. Phase I: Enhancement of the Kronos Simulation Program
No full textThe main purpose of this project is to make KRONOS, a microcomputer-based freeway simulation program under development operational by resolving the following problems problems: detailed field testing and adjustments of the program with real freeway data, analysis of sensitivities in simulation models with respect to the variations in input data, and enhancements of the input/output module to be suitable for the Mn/DOT planning environment.
In addition, a new simulation module to treat special types of freeway segements incluing merging/diverging of two freeways is developed and incorporated into KRONOS in this project. The major accomplisments made in this project are summarized.Michalopoulos, Panos; Kwon, Eil; Lee, Chifung; Mahadevan, Gopalakrishnan; Kang, JeongGyu. (1992). Development of an Integrated Simulation Package for Freeway Design, Operations and Adaptive Traffic Management. Phase I: Enhancement of the Kronos Simulation Program. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/156893
Development and Application of Demand-Responsive Ramp Metering Control to Improve Traffic Management in Freeway Corridors
No full textA method is developed for evaluating traffic-responsive ramp metering strategies and improving freeway performance. The method emulates real-time metering and rigorously traces the interactions between automatic rate-selection metering strategies and freeway performance through time. Given a demand pattern and freeway geometrics, it provides assessment of metering strategies that change continuously at very short time intervals. Further, it explicitly treats time delays that can be caused by hardware or introduced by the traffic engineer.Center for Transportation StudiesStephanedes, Yorgos J.; Kwon, Eil; Chang, Kaikuo; Yao, Ping. (1992). Development and Application of Demand-Responsive Ramp Metering Control to Improve Traffic Management in Freeway Corridors. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/156887
Development and Application of On-Line Strategies for Optimal Intersection Control Phase II: Off-Line Evaluation of Control Strategies and Development of a Live Laboratory
No full textThis project evaluates various intersection control strategies in a simulated environment and also helped establish a live laboratory for use in future testing of new control strategies. The report reviews major intersection control strategies, including the state-of-the-art strategies with adaptive and on-line timing generation features. In addition, it details simulation results for the OPAC control strategy. The NETSIM simulator created the simulation environment for a test network that included part of downtown
Minneapolis. Comparison results indicate that OPAC performs best with low-traffic demands, and pretimed control was the most effective during peak periods when traffic demand reached capacity. In conjunction with this project, Minneapolis city traffic engineers installed a machine-vision video detection system at a live intersection laboratory. Located at Franklin and Lyndale Avenues, the test site will help researchers evaluate new control strategies before full-scale implementation in later phases of
this research.Minnesota Department of TransportationStephanedes, Yorgos J.; Kwon, Eil; Liu, Xiao. (1994). Development and Application of On-Line Strategies for Optimal Intersection Control Phase II: Off-Line Evaluation of Control Strategies and Development of a Live Laboratory. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/155943
Development and Application of On-Line, Integrated Control Strategies for Optimal Metering, Incident Management and Driver Guidance in Freeway Networks: Phase I Final Report
No full textManaging freeway congestion requires an integrated approach involving demand-responsive ramp metering, incident management and driver guidance. While a freeway network acts as a system, i.e., conditions on any part affect other parts in the network, the state of the art in real-time freeway management has not reached the point where comprehensive, network-wide optimal control schemes are automatically generated and implemented through on-line optimization and coordination of various control actions. A major difficulty lies in the lack of efficient computational algorithms implementable for on-line optimization, and the lack of accurate on-line predictors, that can predict traffic demand and diversion in freeway networks. As a result of the above limitations, most traffic responsive metering systems, such as the Twin Cities freeway control system, employ automatic rate-selection procedures. These procedures select the most appropriate metering rates for a ramp from a pre-determined library using the information received from loop detectors on the main freeway, upstream and downstream from the ramp. Although this method provides a degree of self-adjustment to prevailing traffic conditions, the lack of an efficient analysis tool to evaluate and update the key components of the control, i.e., thresholds and rate-libraries, significantly restricts the effectiveness of control.Stephanedes, Yorgos J.; Kwon, Eil; Chang, Kaikuo; Vairamidis, Nikos. (1993). Development and Application of On-Line, Integrated Control Strategies for Optimal Metering, Incident Management and Driver Guidance in Freeway Networks: Phase I Final Report. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/156847
Arterial Link Travel Time Estimation Using Loop Detector Data - Phase I
No full textIn recognition of the need for an effective yet inexpensive way of estimating arterial travel times, MnDOT has sponsored a research project to develop a travel time estimation model using loop detector data. This project is being jointly conducted by researchers from the University of Iowa and the University of Minnesota, and will be carried out in two phases. Phase I involves a literature review, traffic data collection and development of a travel time database, and Phase II covers model development, calibration and evaluation. This report summarizes the findings of Phase I.Zhang, Michael; Wu, Tong Qiang; Kwon, Eil; Sommers, Kevin; Habib, Ahsan. (1997). Arterial Link Travel Time Estimation Using Loop Detector Data - Phase I. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/182586
Development and Application of On-Line Strategies for Intersection Control Phase I: Review of Advanced Control Strategies
No full textSCOOT, SCATS, PRODYN and OPAC represent the state-of-the-art control strategies for signalized traffic network management by employing advanced control concept such as demand-responsive, on-line timing generation with adaptive features. While there have been individual tests of the above state-of-the-art control strategies by various agencies, no comprehensive effort has been made to evaluate and quantify the performance of each strategy, especially in terms of their applicability to both loops and video detection. This research reviews the advanced intersection control strategies developed to date. Due to the lack of field evaluation that can directly compare each control strategy, this study focused on the theoretical principles and implementation issues found from the literature. Further, the existing intersection control systems in three major cities in the U.S. and Canada are analyzed and their control algorithms are introduced. Finally, the current status of the video detection development is also reviewed.Center for Transportation StudiesStephanedes, Yorgos J.; Kwon, Eil; Michalopoulos, Panos G.; Mallis, John; Roetzel, Ronald. (1992). Development and Application of On-Line Strategies for Intersection Control Phase I: Review of Advanced Control Strategies. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/155938
Development of Traffic Simulation Laboratory For Design Planning and Traffic Operations (Phase I)
No full textThe key element in improving traffic operations and performing effective real time management is the ability to assess the effectiveness of the various alternatives prior to implementation. Simulation methods have long been recognized as the most effective tool for such an analysis, and various simulators have been developed by different agencies for freeway and arterial networks. While there have been individual tests of each software by various agencies, no comprehensive effort has been made to quantify and evaluate the performance of each model. The major difficulty includes the lack of detailed real data and the time-consuming manual effort to prepare input information for each software. To be sure there is no user-interface developed to data that can generate input files for different simulators with a common set of data. Recent installation of the state-of-the art video detection systems in the 1-394 freeway provides a unique opportunity to develop a comprehensive freeway database that can be used to create various test cases with detailed traffic database that can be used to create various test cases with detailed traffic information. Further, the 1-494 Integrated Corridor Traffic Management project being conducted by MN/DOT will be able to provide valuable corridor traffic data which can be used for evaluating freeway/arterial network models. By evaluating existing traffic simulation models the advantages/disadvantages of each model can be identified. Based on the evaluation results a comprehensive modeling approach for freeway/arterial networks can be developed. The ultimate goal of this research is to develop a traffic simulation laboratory where various roadway design/operational alternatives can be evaluated with traffic simulators under an integrated database-simulation environment. The proposed research, Phase I, will evaluate existing freeway simulation models with detailed traffic data to be collected using machine-vision an loop detection systems.Center for Transportation StudiesMichalopoulos, Panos; Sommers, Kevin; Reynhout, Kenneth; Kota, Ramesh; Kwon, Eil. (1996). Development of Traffic Simulation Laboratory For Design Planning and Traffic Operations (Phase I). Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/155329
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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