Fall 2005 UMASS Amherst
Operations Research / Management Science Seminar Series

Date: Friday, October 14, 2005

Time: 11:00 AM
Location: Isenberg School of Management, Room 112

Speaker: Professor Clara Fang

Department of Civil, Environmental, and Biomedical Engineering
University of Hartford
West Hartford, CT

Biography: Fang (Clara) Fang received her Ph.D. in transportation engineering from the Pennsylvania State University in 2004. Presently, she is an Assistant Professor in the Department of Civil Engineering at the University of Hartford. She has been working on real-time traffic signal control and optimization for diamond interchanges, which has previously been recognized as outstanding Ph.D. dissertation work obtaining a distinction award from the Pennsylvania State University and a Fellowship from the Mid-Atlantic Universities Transportation Center. Dr. Fang was one of the key members carrying out the NCHRP 3-60 project that led to a revised Chapter 26 for Interchange Ramp Terminals Operational Analysis of Highway Capacity Manual. Her research is focused on traffic flow theory, adaptive signal control & optimization, simulation, intelligent transportation systems (ITS), work zone safety and highway design. Dr. Fang has been actively involved in the Transportation Research Board (TRB)’s Traffic Control Systems Committee, and Capacity and Quality of Service Committee activities.
TITLE: Optimal and Adaptive Signal Control of Diamond Interchanges
Abstract: This research has developed a methodology and a corresponding implementation algorithm to provide optimal signal control of diamond interchanges in response to real-time traffic fluctuations. The problem, solved by a forward dynamic programming (DP) method, is formulated as to find a phase sequencing decision with a phase duration that makes a pre-specified performance measure minimized over a finite horizon that rolls forward. The optimal signal switches over each 2.5-second interval are found for each horizon of 10 seconds. The optimization process is based on the advanced vehicle information obtained from loop detectors set back a certain distance from the stop-line. Vehicle trajectories from detections till future arrivals and departures are modeled at the microscopic level to estimate the traffic flows at the stop-line for each horizon. The DP algorithm is coded in C++ language and dynamically linked to AIMSUN, a stochastic micro-simulation package, for evaluation. The simulation results have exhibited that the DP algorithm is superior to PASSER III and TRANSYT-7F in handling demand fluctuations for medium to high flow scenarios when the field demand is increased from the one used in off-line optimization. The performance of the three algorithms is almost identical if the simulation demand is similar to off-line demand situation and dose not vary much.
This series is organized by the UMASS Amherst INFORMS Student Chapter. Support for this series is provided by the Isenberg School of Management, the Department of Finance and Operations Management, INFORMS, and the John F. Smith Memorial Fund.

For questions, please contact the INFORMS Student Chapter Representative, Ms. Tina Wakolbinger, wakolbinger@som.umass.edu