Lihui Wu

The Research of Using Ant Colony Algorithm in Solving Sequencing Problem of Mixed Model Assembly Lines with Multi-objectives

Mixed model assembly lines (MMAL) sequencing problem is a typical NP-hard problem. Its important to search for an optimal sequence to maximize the efficiency of production lines. Therefore this work proposes a new mathematic programming model for measuring the efficiency of MMAL. A modified ant colony algorithm (MACA) is developed to determine a sequence which optimizes the objective function with elitist strategy. The experimental results indicate the applicability of the proposed objective function and availability of the algorithm in solving this problem.

A Greedy Dynamic Priority Dispatching Policy for Intrabay in Semiconductor Wafer Fabrication System

The automation of intrabay system in 300mm semiconductor wafer fabrication system is complex due to complicated product mixes, mass and dynamic transportation demands, transportation deadlock, and vehicle blockage. To obtain better overhead hoist transport (OHT) dispatching solution in intrabay system, a fuzzy logic based greedy dynamic priority dispatching policy is proposed. With experimental data from a 300mm semiconductor wafer fabrication system, it is demonstrated that the proposed approach has the better comprehensive performance than FEFS dispatching rule in aspect of cycle time, delivery time, transport time, movement, throughput, due date satisfaction, and WIP in intrabay system.