摘要:

AbstractThe optimal design of a supply chain was approached in two phases by using: (1) a mathematical programming formulation and heuristic solution approach to minimize the distinct number of product types held at various points in the supply chain; and (2) a spreadsheet inventory model to estimate the safety stock needed to absorb random fluctuations in both demand and lead time throughout the system. This two-phased approach allowed management to quantify the effects of inventory required for locating parts of the supply chain in different geographic areas. The quantification of projected inventory requirements was a critical input used by senior management to clarify their final decision-making process.

ISSN:0160-5682    

DOI:10.1057/jors.1993.113

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractWood processing on a centralized conversion site can be considered as a cutting stock problem. The multiperiod optimization of the production system is a very hard problem to solve. A balance has to be made between value recovery optimization and service rate maximization. In this research a decision support system was designed and built to support production planning. Strategic, tactical and operational planning are covered, but here the focus is primarily on tactical planning.

ISSN:0160-5682    

DOI:10.1057/jors.1993.114

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractRapid advances in computing and communications technology have made distributed computing an attractive alternative for geographically dispersed organizations. A telecommunication sub-network forms the backbone of these distributed systems. In general, this paper focuses on the assignment of communication channel capacities in the presence of time variant usage patterns. Specifically, we concentrate on long-range capacity planning for organizations that construct networks by leasing communication channels from telecommunication companies. We formulate the capacity assignment problem as a 0-1 integer program that seeks to minimize total leasing cost subject to communication delay restrictions. Unlike previous models that include a single-system wide-average delay constraint, our model allows the flexibility of specifying delay restrictions by communicating node pairs. We propose an efficient heuristic, and a Lagrangian relaxation based procedure to obtain performance guarantees on the solution obtained from the heuristic.

ISSN:0160-5682    

DOI:10.1057/jors.1993.115

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThe assignment problem (AP) and bottleneck assignment problem (BAP) are well studied in operational research literature. In this paper we consider two related problems which simultaneously generalize both AP and BAP. Unlike AP and BAP, these generalizations are strongly NP-complete. We propose two heuristics to solve these generalized problems: one based on a greedy principle and the other based on tabu search. Computational results are presented which show that these heuristics, when used together, produce good quality solutions. Our adaptation of tabu search also gives some new insight into the application of tabu search on permutation problems.

ISSN:0160-5682    

DOI:10.1057/jors.1993.116

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis paper addresses a multiperiod integrated model that plans deliveries to customers based upon inventories (at warehouse and customer locations) and vehicle routes. The model determines replenishment quantities and intervals at the warehouse, and distribution lots and delivery routes at customer locations. We investigate coordination of customer and warehouse replenishment decisions and illustrate their interdependence. Computational experience on randomly generated problems is reported. We show that ordering policy at the warehouse is a function of how goods are distributed to lower echelons and that coordination leads to cost reduction.

ISSN:0160-5682    

DOI:10.1057/jors.1993.117

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis paper describes an interactive 3D animation approach that may help with the investigation, understanding and interpretation of results for a Visual Interactive Simulation (VIS) project. The method uses a graphics algorithm to draw on a computer screen‘3D contour maps’which show the response of a simulation model to changes in its input parameters. A previous paper showed that it is possible for a neural network to learn the response of a simulation. This paper shows that the speed of response of a neural network can be exploited so that 3D animation sequences of the simulation's results can be produced. It is possible to rotate the‘3D contour map’, zoom, pan, or generally view the projection from different perspectives. Two example problems are described. The paper suggests that this approach can further improve the quality of VIS by being able to give comprehensive graphic 3D sensitivity analyses to the original problem under investigation.

ISSN:0160-5682    

DOI:10.1057/jors.1993.118

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractIn this paper we model a single-base multi-indentured repairable item inventory system. The base has a maximum number of identical on-line machines, and each machine consists of several module types. Our objective is to calculate the steady-state operating characteristics of the system. The usual Markovian approach leads to multidimensional state spaces that are large even for relatively small problems. Solving such a multidimensional system is very difficult because of the huge number of states. Consequently, we propose an approximation technique that allows us to solve large problems relatively quickly. Although the resulting solution is only approximate, a variety of test problems indicates that the algorithm is quite accurate.

ISSN:0160-5682    

DOI:10.1057/jors.1993.119

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis paper shows how to modify the smoothing constant for use in an Exponentially Weighted Moving Average system, when data has to be combined either across a number of periods, or is available from only a fraction of a normal forecast review interval.

ISSN:0160-5682    

DOI:10.1057/jors.1993.120

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis paper introduces an alternative approach for determining lot sizes for purchased components in MRP environments where discounts are available from vendors. This new method is a variation of the least period cost procedure, which was previously found to be a poor performer relative to the least unit cost, McLaren's order moment, and the Chunget al.procedures. The performance of this new version of the least period cost procedure, which actually is a modified version of the original Silver-Meal heuristic, is found to be excellent relative to alternative procedures. In fact, when flexibility of the method to operate in diverse environments and computational time are considered, this modified least-period cost heuristic may be the best procedure available.

ISSN:0160-5682    

DOI:10.1057/jors.1993.121

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractA simple method is presented for determining‘closed-form’solutions for an optimum (s, S) ordering policy for the single-period inventory problem with a set-up cost of ordering and the uncertain total demand over the period represented by a triangular probability density function. The distribution reflecting the decision maker's degree of belief that all values of total demand outside of two (possibly‘soft’) limits are barely credible and all values within the limits have uniform increasing probability density towards a (possibly‘soft’) modal value. The importance of the closed form solutions obtained is that they remove the need for enumeration over alternative values of s in determining the optimum (s, S) ordering policy, also they can be encoded in an algorithm simple to implement and they allow easy sensitivity analysis of the results to perturbations in the estimates of the problem parameters. A numerical example is presented to illustrate the essential features of the method.

ISSN:0160-5682    

DOI:10.1057/jors.1993.122

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor