MULTI-TASK TRANSPORTATION SYSTEM: THE OPERATION PROBLEM

Abstract and Figures The reachability problem of a network representing a transportation system is generally solved by showing the linkage between all loading/unloading (origin/destination) stations and each network intersection. This approach solves single-vehicle problems in a system that is required to perform one task. When there are a number of vehicles in the transportation system and several tasks to be performed, it is not clear that all the tasks can still be performed (because of blocking, turning ability, or other constraints). Moreover, when it is feasible, the method of execution, which will optimally achieve various objective functions, is not a trivial matter. In this paper, we present the problematic nature of traffic control for a pushing/towing system (a railroad, narrow lanes or aisles, a fixed guide path), develop a simple example that fully illustrates the difficulties, and suggest a number of methodologies for solving the problem: a) linear integer programming; b) shortest-path approach; c) branch-and-bound approach and for future research; and, d) an interactive approach using the branch-and-bound technique. Significance: The paper analyzes the operation problem of multi-task transportation systems and provides several approaches for solving this problem.