Abstract
A local area network under development at DETUA is described. The network topology is geographically centralized, although access and control to the shared transmission medium is distributed. This results in a number of advantages when compared with conventional topologies.

Abstract
This paper presents two new solution procedures for a deterministic lot size problem, a matrix algorithm and a heuristic matrix method. The algorithm is based on the dual of a linear programming model formulation of the lot size problem, and it provides optimal solutions even in the general case of time-varying parameters. A comparison of the efficiency of the new solution procedures with well-known methods is developed. New applications of the techniques described within the fields of engineering (optimal design of a pump-pipe system) and economics (a model for import-planning) are referred to. © 1984 Taylor & Francis Group, LLC.

Abstract
In this paper the problem of minimizing the total cost of a pump-pipe system in series is considered. The route of the pipeline and the number of pumping stations are known. The optimization will then consist in determining the control variables, diameter and thickness of the pipe and the size of the pumps. A general mathematical model is formulated and Dynamic Programming is used to find an optimal solution. Practical reasons, derived from the techniques engineers generally use to cope with such problems, and special characteristics of the mathematical structure of the model justified the consideration of particular cases of the system. This analysis, based on Dynamic Programming, enabled us to elaborate a simple heuristic method, condensing those techniques, and supplied sufficient conditions for the heuristic to operate as an optimal procedure. The solution of a realistic example confirms the viability of the conditions developed and tests the formulation (also presented) of the optimization problem by the Discrete-Time Optimum Principle for the general control problem.

Abstract
The object of this study is to consider how one could enable two or more Prolog-like systems to talk about problem solutions, and how more complex modes of communication could be defined in this framework. A 'reference list' associated with each clause indicates to which system the clause belongs (and where it came from). If a reference list is associated with an expression, it determines where this expression is to be sent if the appropriate action is taken. A special metapredicate is used to associate the answer (or answers) directly with each problem solved, and so, failures, for example, are represented in an explicit manner. The metapredicates sent to other systems may include the existing metapredicates of Prolog, the new metapredicates introduced, or conjunctions and disjunctions of metapredicates.

Abstract

Abstract