Shi-Chung Chang

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Group elevator scheduling has long been recognized as an important problem for building transportation efficiency, since unsatisfactory elevator service is one of the major complaints of building tenants. It now has a new significance driven by homeland security concerns. The problem, however, is difficult because of complicated elevator dynamics, uncertain(More)
Building emergency evacuation has long been recognized as an important issue, and crowd guidance is a key to improve egress efficiency and occupant survivability. Most existing methods assume that crowd behaviors are independent of emergency situations and are fully controllable under guidance. This assumption makes it difficult to capture important(More)
Deregulated electricity markets use an auction mechanism to select offers and their power levels for energy and ancillary services. A settlement mechanism is then used to determine the payments resulting from the selected offers. Currently, most independent system operators (ISOs) in the United States use an auction mechanism that minimizes the total offer(More)
This paper describes the design of a two-level hierarchical production scheduling engine, which captures the industrial practice of mass production semiconductor fabrication factories (fabs). The two levels of the hierarchy consist of a mid-term scheduler and a short-term scheduler, and are aimed at achieving coordination between the fab-wide objectives and(More)
In building emergency evacuation, the perception of hazards can stress crowds, evoke their competitive behaviors, and trigger disorder and blocking as they pass through narrow passages (e.g., a small exit). This is a serious concern threatening evacuees' survivability and egress efficiency. How to optimize crowd guidance while considering such effects is an(More)
This paper presents a Lagrangian relaxation-based approach for production scheduling of flexible flow shops (PSFFS) where sequence-dependent setup effects (time and cost) are significant. The approach exploits the idea that scheduling the production of individual parts without considering machine setup effects and scheduling the use of a machine to process(More)
Information communication technology (ICT) enabling energy efficiency has been considered as the fastest way to reduce carbon CO<inf>2</inf> generation, while replacement energy may take decades to deploy. We start observations of electricity flow in the power grid and suggest a distributed optimization of electricity usage under a hierarchical structure(More)