Showing papers by "André Langevin published in 2002"

Sector Design for Snow Removal and Disposal in Urban Areas

Abstract: Snow removal and disposal are important and expensive winter operations in many cities. When a large amount of snow accumulates in an urban area and impedes traffic, the snow must be removed to snow disposal sites. This paper first briefly describes snow disposal operations in Montreal, Quebec, Canada. It then presents models and efficient algorithms for partitioning a city into sectors for snow disposal operations, and for assigning the sectors to disposal sites. These algorithms are incorporated in a decision support system (DSS) built on a geographic information system. The DSS provides initial solutions, and allows the planner to interactively design sectors to incorporate difficult constraints. Results and some sensitivity analyses are presented for the City of Montreal.

Dispatching and Conflict-Free Routing of Automated Guided Vehicles: An Exact Approach

Abstract: This article presents an exact solution approach for the problem of the simultaneous dispatching and conflict-free routing of automated guided vehicles. The vehicles carry out material handling tasks in a flexible manufacturing system (FMS). The objective is to minimize the costs related to the production delays. The approach is based on a set partitioning formulation. The proposed model is solved to optimality by a column generation method, which is embedded in a branch-and-cut exploration tree. The proposed model and solution methodology are tested on several scenarios with up to four vehicles in the manufacturing system. The results show that most of these scenarios can be solved to optimality in less than three minutes of computational time.

Typologie des réseaux de manutention

Abstract: Most authors addressing the facility layout problem consider that the selection of the material handling network is done a priori. The material handling network layouts found in the literature are mainly of classical type, i.e. I, L, T, H, U, X, O and 8. In industrial settings, the layouts are usually more complex. In this article, a typology, based on the level of complexity, is proposed to classify the material handling networks. The typology allows to consider all types of networks found in the industry and to classify them according to common characteristics. Thus, methods and models for facility layout design could be used for all the network layouts in the same class. Variability among the different industrial settings is thus minimized. A survey on the material handling networks of manufacturers from France and Quebec has been conducted. The results are used to validate the proposed typology. The survey shows surprisingly that there are no links between the type of facility layout and the network layout.