摘要:

AbstractData was gathered from Fortune 500 companies (manufacturing and service organizations) and 500 small firms pertaining to the use of several quantitative techniques. Analysis was also done to see if differences existed within different classes of service companies. Also, respondents were asked for their opinion pertaining to specific barriers that may inhibit the use of these techniques. Results show little progress has been made in the applications of quantitative techniques in the last decade. The barriers cited by respondents are mostly related to management's lack of knowledge of quantitative techniques. Findings agree with previous studies conducted.

ISSN:0160-5682    

DOI:10.1057/jors.1988.168

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThe multi-item single-level capacitated lot-sizing problem consists of schedulingNdifferent items over a horizon ofTperiods. The objective is to minimize the sum of set-up and inventory-holding costs over the horizon, subject to a capacity restriction in each period. Different heuristic approaches have been suggested to solve this difficult mathematical problem. So far, only a few limited attempts have been made to analyse and compare these approaches. The paper can be divided into two main parts. The first part shows that current heuristics can be classified in two different categories: single-resource heuristics, which are special-purpose methods, and mathematical-programming-based heuristics, which can usually deal with more general problem environments. The second part is devoted to an extensive computational review. The general idea is to find relationships between the performance of the heuristic and the computational burden involved in finding the solution. Based on these computational results, suggestions can be given with respect to the usefulness of the various heuristics in different industrial settings.

ISSN:0160-5682    

DOI:10.1057/jors.1988.169

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractIt is well known that no particular forecasting agency dominates when the accuracy of economic forecasts of the UK is investigated. There are good reasons for believing that if forecasts differ, some combination of them will be an improvement over the individual forecasts. The problem is to determine what weights to attach to each forecast. Various methods have been suggested in the literature, including equal weights (averaging), optimal weights (linear regression), varying weights based on past performance, and the Bayesian approach. We review these methods and examine their performance for important macro-economic variables.

ISSN:0160-5682    

DOI:10.1057/jors.1988.170

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractA linear programming problem is presented to solve a problem in determining how many herbivores are needed to stock a small game reserve. The resulting problem has several conflicting objectives. The interactive algorithm which was used to solve the problem is then outlined. The interactive approach is then applied to the problem in order to find a satisfactory solution. Certainad hocimprovisations which were needed in the final stages are outlined.

ISSN:0160-5682    

DOI:10.1057/jors.1988.171

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractIn decentralized systems, the objectives at the different levels often differ. Each level controls only a subset of the decision variables but is affected by the decisions made at the other levels. Recent methods in bi-level linear programming solve such systems better than decomposition methods. Here, the bi-level LP is extended to a bi-level system with many decision-makers at the lower level, and a tri-level system with one decision-maker at each level. In both of these cases, the higher level acts as the leader and the lower level as the follower in the Stackelberg game. The resulting techniques are illustrated with simple numerical examples.

ISSN:0160-5682    

DOI:10.1057/jors.1988.172

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractLagrangian relaxation has been widely used in solving a number of hard combinatorial optimization problems. The success of the approach depends on the structure of the problem and on the values assigned to the Lagrange multipliers. A recent paper on the single-source capacitated facility-location problem proposed the use of Lagrangian relaxation in which the capacity constraints were relaxed. In this paper, a class of such problems is defined for which the proposed relaxation is guaranteed to result in an infeasible solution, irrespective of the values assigned to the Lagrange multipliers. In these cases, the bounds on the optimal solution, obtained from the relaxation, are generally poor. It is concluded that, when using Lagrangian relaxation, it may be worthwhile carrying out a preliminary analysis to determine the potential viability of the approach before extensive development takes place.

ISSN:0160-5682    

DOI:10.1057/jors.1988.173

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThis paper deals with the problem of determining the economic operating policy for inventory items which are manufactured jointly but packaged individually. A modification is proposed to Silver's algorithm, which is generally believed to be the simplest heuristic algorithm for determining the economic operating policy for jointly replenished items.

ISSN:0160-5682    

DOI:10.1057/jors.1988.174

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThe 0-1 knapsack problem is a linear integer-programming problem with a single constraint and binary variables. The knapsack problem with an inequality constraint has been widely studied, and several efficient algorithms have been published. We consider the equality-constraint knapsack problem, which has received relatively little attention. We describe a branch-and-bound algorithm for this problem, and present computational experience with up to 10,000 variables. An important feature of this algorithm is a least-lower-bound discipline for candidate problem selection.

ISSN:0160-5682    

DOI:10.1057/jors.1988.175

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThe model of the sale based on the growth matrix shows a double aspect of growth: one which is related to the direct growth rates and which expresses the intensity of sales, and another which is related to the indirect rates and shows a relative sales growth of one product in relation to another. The indirect sales growth provides us with knowledge about the relative relations of the sales growth. By simultaneous observation of the direct and indirect growth rates, we are in a position to find out the absolute and relative changes of sales during a period of time, and through the matrix of growth we present a complete structure of the sales growth.

ISSN:0160-5682    

DOI:10.1057/jors.1988.176

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractIn this paper a linear time heuristic for a class of cyclic staffing problems with breaks is described. A novel feature of the heuristic is that the quality of the heuristic solution increases as the requirements for each period become more uniform. As a by-product of this work, a new class of polynomially solvable set-covering problems is identified.

ISSN:0160-5682    

DOI:10.1057/jors.1988.177

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor