Sylvain Housseman

A relax-and-repair heuristic for the Swap-Body Vehicle Routing Problem

In this paper we address the Swap-Body Vehicle Routing Problem (SB-VRP), a variant of the truck and trailer routing problem. It was introduced in the VeRoLog Challenge 2014. We develop a solution approach that we coin Relax-and-Repair. It consists in solving a relaxed version of the SB-VRP and deriving a feasible solution by repairing the relaxed one. We embed this approach within a population-based heuristic. During computation we store all feasible routes in order to derive better solutions by solving a set-partitioning problem. In order to take advantages of nowadays multi-core machines, our algorithm is designed as a collaborative parallel population-based heuristic. Experimental results show that our relax-and-repair algorithm is very competitive and point the impact of each phase on the quality of the obtained solutions. The advantage of our approach is that it can be adapted to solve complex industrial routing problems.

Skipping algorithms for defect inspection using a dynamic control strategy in semiconductor manufacturing

In this paper, we propose new ways for efficiently managing defect inspection queues in semiconductor manufacturing when a dynamic sampling strategy is used. The objective is to identify lots that can skip the inspection operation, i.e. lots that have limited impact on the risk level of process tools. The risk considered in this paper, called Wafer at Risk (W@R), is the number of wafers processed on a process tool between two defect inspection operations. An indicator (GSI, Global Sampling Indicator) is used to evaluate the overall W@R and another associated indicator (LSI, Lot Scheduling Indicator) is used to identify the impact on the overall risk if a lot is not measured. Based on these indicators, five new algorithms are proposed and tested with industrial instances. Results show the relevance of our approach and that evaluating sets of lots for skipping performs better than evaluating lots individually.

Impacts of radio-identification on cryo-conservation centers through simulation

This paper deals with using simulation as a decision support tool for estimating the impact of RFID technologies within biological sample storage areas (called biobanks). Several indicators, including inventory reliability or human resource utilization, are compared and discussed for different scenarios of use of the technologies. A special emphasis is put on the so-called re-warehousing activity that RFID makes possible, and which consists in reassigning tubes to empty places when box are emptied. Optimization algorithms are developed and embedded in the simulator. Results demonstrate the potential interest of RFID in biobanks and the value of simulation for estimating and optimizing such complex socio-technical systems.

Impacts of radio-identification on cryo-conservation centers

This paper deals with using simulation as a decision support tool for estimating the impact of RFID technologies within biological sample storage areas (called biobanks). Several indicators, including inventory reliability or human resource utilization, are compared and discussed for different scenarios of use of the technologies. A special emphasis is put on the so-called re-warehousing activity that RFID makes possible, and which consists in reassigning tubes to empty places when box are emptied. Optimization algorithms are developed and embedded in the simulator. Results demonstrate the potential interest of RFID in biobanks and the value of simulation for estimating and optimizing such complex socio-technical systems.

Smart dynamic sampling for wafer at risk reduction in semiconductor manufacturing

Semiconductor manufacturing is highly complex and expensive, hence the early detection of problems is necessary to minimize the number of scraps and improve the overall yield. This paper presents an industrial application of dynamic sampling based on an aggregated risk indicator at process tool level. The objective is to identify the lots that should be measured to minimize the overall risk level of the fabrication plant (fab). Results show significant improvements compared with the previous strategy: Sampling decisions are better adapted to the current production state and to the workload in the inspection area. Several parameters and algorithms are proposed and compared using industrial data.