The two-echelon capacitated vehicle routing problem: models and math-based heuristics

Multiechelon distribution systems are quite common in supply-chain and logistics. They are used by public administrations in their transportation and traffic planning strategies, as well as by companies, to model own distribution systems. In the literature, most of the studies address issues relating to the movement of flows throughout the system from their origins to their final destinations. Another recent trend is to focus on the management of the vehicle fleets required to provide transportation among different echelons. The aim of this paper is twofold. First, it introduces the family of two-echelon vehicle routing problems (VRPs), a term that broadly covers such settings, where the delivery from one or more depots to customers is managed by routing and consolidating freight through intermediate depots. Second, it considers in detail the basic version of two-echelon VRPs, the two-echelon capacitated VRP, which is an extension of the classical VRP in which the delivery is compulsorily delivered through intermediate depots, named satellites. A mathematical model for two-echelon capacitated VRP, some valid inequalities, and two math-heuristics based on the model are presented. Computational results of up to 50 customers and four satellites show the effectiveness of the methods developed

Simulation Testing of Aggregate Production Planning Models in an Implementation Methodology

The planning of production, inventories, and work force at an aggregate level to respond to fluctuating demands on a production system has received substantial theoretical treatment in the literature for several years. However, widespread implementation of the available analytical techniques has not occurred. The objectives of this research are to explore this implementation problem: (1) by developing a simulation model of an operating firm, (2) by using this simulation to compare the performance of aggregate production planning models, and (3) by formulating a generalized methodology for implementing quantitative planning models into the decision procedures of operating firms.

Note--A Note on El-Shaieb's New Algorithm for Locating Sources Among Destinations

The objective of this note is (i) to identify and briefly review some references not included in [El-Shaieb, A. M. 1973. A new algorithm for locating sources among destinations. Management Sci. 20 221-231.] as well as more recent additions and (ii) to give computational comparisons of three other solution methods with that of El-Shaieb on his 30-city test data.