An Iterated Local Search for the Budget Constrained Generalized Maximal Covering Location Problem

Capacitated covering models aim at covering the maximum amount of customers’ demand using a set of capacitated facilities. Based on the assumptions made in such models, there is a unique scenario to open a facility in which each facility has a pre-specified capacity and an operating budget. In this paper, we propose a generalization of the maximal covering location problem, in which facilities have different scenarios for being constructed. Essentially, based on the budget invested to construct a given facility, it can provide different service levels to the surrounded customers. Having a limited budget to open the facilities, the goal is locating a subset of facilities with the optimal opening scenario, in order to maximize the total covered demand and subject to the service level constraint. Integer linear programming formulations are proposed and tested using ILOG CPLEX. An iterated local search algorithm is also developed to solve the introduced problem.     

Decision Making with Linear Partial Information (L.P.I.)

This paper deals with decision making in a set of circumstances intermediate between the classical extremes of pure risk and pure uncertainty. It extends the Cannon-Kmietowicz-Pearman methods of finding maximum and minimum expected values of strategies, when probabilities of occurrence of future states of nature can be ranked, to the more general case investigated by Kofler and Menges, in which a set of linear constraints is imposed on the probabilities. A general solution to the problem is obtained, and its relationship to earlier results is discussed. A new criterion for strategy choice, in the condition mentioned above, is also proposed. It recommends selection of a strategy with the highest minimum expected utility (max E_min). The criterion arises naturally from the extension of the von Neumann-Morgenstern utility theory to the case of incomplete knowledge about the probabilities. These developments greatly enhance the attractiveness of the earlier results for applied work and lay foundations for further theoretical advances.     

Maximal Norm of C(S)

1991 Mathematics Subject Classification 46B20, 46B04.     

The Ex-Post Evaluation of the Minimum Local Reliability Level: An Enhanced Probabilistic Location Set Covering Model

In order to evaluate the behavior of three probabilistic location set covering models we propose a new method that allows the ex-post measurement of the so called minimum local reliability level, both under the independence and under the dependence assumption. We show experimentally, by means of a set of test problems, that the proposed loss-system version of Ball and Lin's model (1993) does almost always achieve the required reliability level. Moreover, if we compare this new version with the other two already known probabilistic models and consider as a second additional criteria the least number of required vehicles, we show that the new version has a better behavior both under the independence and the dependence assumption. In this paper we further propose a new model with the aim of reducing the number of required vehicles while satisfying the fixed reliability level. Our new model is formulated like Ball and Lin's model incorporating the servers workload estimate of the Binomial PLSCP of ReVelle and Hogan (1988). Finally, we check the precision of our ex-post evaluation method over the four considered models through a simulation study.     

从“许氏模型”想到的……

This article gives a brief exposition of P. L. Hsu's model of the best quadratic estimate of variance. As is well known, the idea of methodology suggested by Hsu's model has been proved quite successful and fruitful in many subsequent investigations and is therefore worth noticing and learning.     

预测地区公民旅游消费额的L.R—L.P模型

如何对地区公民旅游消费总额进行预测 ,是经济工作者及相关行业关注的问题 .本文用模糊系统分析的方法 ,建立一个地区的 L.R— L.P模型 ,利用模型的参数进行预测 ,提供一种辅助方法 .     

Schedule Based M.R.P.: An Integrated Approach to Production Scheduling and Material Requirements Planning

This paper presents an integrated approach to production scheduling and materials requirements planning. It discusses existing techniques and suggests how the new method can overcome certain deficiencies. The method is incorporated in a computer program, and sample outputs for an example problem are given. Some industrial experience is reported.     

覆盖S-粗集模型的性质

讨论基于覆盖理论的S-粗集模型的性质,给出了S-粗集生成的拓扑结构,证明了覆盖S-粗集模型与自反、传递关系下的S-粗集模型是等价的。     

Some applications of the L.P.L. language to combinatorial programming

Four application cases of the L.P.L. language are presented here. We show that L.P.L. provides extended possibilities for the building of combinatorial programs.     

The L.P.D.E.M., a mixed finite difference method for elliptic problems

Summary A mixed finite difference method is analyzed for solving certain elliptic problems. This method, called L.P.D.E.M. (Locally exact Partial Differential Equation Method) was initially proposed in the frame of hydrodynamic lubrication. Convergence is obtained. Relations between this scheme and homogenization theory are also discussed. For a one-dimensional elliptic equation with no zero-order term and in conservative form, this method is an exact one. Some numerical results will also be given.     

A Survey on Recent Results of the Mathematical Seminar in Perugia, inspired by the Work of Professor P.L. Butzer

Here we give a survey on recent results in approximation theory obtained by a group of mathematicians of the University of Perugia, inspired by the work of Professor Butzer. We collect some results concerning linear integral operators in various settings.     

灰色工序时间的统筹方法及其应用

用传统的统筹方法解决实际问题时 ,有些工序时间难以确定 .根据灰色系统的思想确定工序时间 ,使统筹方法的应用更简单、更方便 .本文给出了一个实际例子 .     

About the properties (V) and (R.D.P.) in injective tensor products

Rendiconti del Circolo Matematico di Palermo Series 2 - In questo lavoro vogliamo provare che seX è uno spazio di Banach del tipoL ∞ con la proprietà (V) of Pelczynski...