Open Access. Powered by Scholars. Published by Universities.®
Operations Research, Systems Engineering and Industrial Engineering Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering
A Comparison Of Traffic Models: Part 1, Framework, Hong Lo, Wei-Hua Lin, Lawrence Liao, Elbert Chang, Jacob Tsao
A Comparison Of Traffic Models: Part 1, Framework, Hong Lo, Wei-Hua Lin, Lawrence Liao, Elbert Chang, Jacob Tsao
Faculty Publications
This report defines a framework for comparing dynamic traffic models. It emphasizes four dimensions: functionality, traffic dynamics, route choice dy namics, and overall network performance. The first dimension compares the models through a check-list of model functions. Regarding the last three comparison dimensions, a total of five networks and twelve scenarios are defined. These test scenarios are designed to accentuate model properties and differences. Also included in the report are a list of performance measures for comparison purpose, and a discussion of the interpretation of results.
Dynamic Traffic Assignment For Automated Highway Systems: A Two-Lane Highway With Speed Constancy, H.-S. Jacob Tsao
Dynamic Traffic Assignment For Automated Highway Systems: A Two-Lane Highway With Speed Constancy, H.-S. Jacob Tsao
Faculty Publications
Dynamic traffic assignment through analytical modeling and optimization has been widely accepted by the IVHS R&D community as a promising traffic control tool for understanding and relieving traffic congestion on conventional highways and city streets. Due to the completely controlled nature of AHS traffic, dynamic assignment of AHS traffic is even more promising. One added dimension of complexity associated with AHS dynamic traffic assignment is lane assignment. Lane changes, for fully utilizing AHS capacity or for exiting, incur disturbances to and hence reduction of longitudinal flow. Intelligent lane assignment is necessary to ensure a high rate of successful exiting, to …
Constraints On Initial Ahs Deployment And The Concept Definition Of A Shuttle Service For Ahs Debut, H.-S. Jacob Tsao
Constraints On Initial Ahs Deployment And The Concept Definition Of A Shuttle Service For Ahs Debut, H.-S. Jacob Tsao
Faculty Publications
The concept of automated highway system (AHS) was motivated primarily by its potential for large capacity and safety gains without requiring significant right-of-way acquisition. However, highway automation involves a multitude of design options as well as systems issues. Compounded by the crucial dimension of evolving the current highway system towards the mature AH& there exist a large number of possible evolutionary paths to AHS. Perhaps due to the immense complexity, little attention has been paid to the evolution dimension.Particularly important and difficult in defining a deployment sequence is the very first step,i.e. the first user service involving fully automated (hands-off …
Stage Definition For Ahs Deployment And An Ahs Evolutionary Scenario, H.-S. Jacob Tsao
Stage Definition For Ahs Deployment And An Ahs Evolutionary Scenario, H.-S. Jacob Tsao
Faculty Publications
The concept of automated highway systems (AHS) as a means to solve the fast-worsening highway congestion problem has received renewed attention recently. Pros and cons of various mature AHS have been a subject of intense study. However, such discussions are nothing but intellectual exercises unless the issue of how to evolve the current highway systems towards these mature AHS can be resolved. There exist a large number of different possible mature AHS. The additional dimension of evolution leads to an even larger number of possible evolutionary scenarios. This paper proposes an approach to defining evolutionary scenarios and illustrates it with …
Linear Programming With Inequality Constraints Via Entropic Perturbation, Jacob Tsao, Shu-Cherng Fang
Linear Programming With Inequality Constraints Via Entropic Perturbation, Jacob Tsao, Shu-Cherng Fang
Faculty Publications
A dual convex programming approach to solving linear programs with inequality constraints through entropic perturbation is derived. The amount of perturbation required depends on the desired accuracy of the optimum. The dual program contains only non-positivity constraints. An ϵ-optimal solution to the linear program can be obtained effortlessly from the optimal solution of the dual program. Since cross-entropy minimization subject to linear inequality constraints is a special case of the perturbed linear program, the duality result becomes readily applicable. Many standard constrained optimization techniques can be specialized to solve the dual program. Such specializations, made possible by the simplicity of …