Showing papers in "Journal of the Operational Research Society in 1989"
319 citations
TL;DR: In this paper, an order-level inventory model for deteriorating items with uniform rate of production and stock-dependent demand is developed, where shortages are allowed, and excess demand is backlogged.
Abstract: An order-level inventory model is developed for deteriorating items with uniform rate of production and stock-dependent demand. Shortages are allowed, and excess demand is backlogged. Results are illustrated with numerical examples.
306 citations
236 citations
TL;DR: Two theorems that include the results of the RPS model are proved in the new inventory model, a single-period, single-product inventory model with several individual sources of demand.
Abstract: This paper deals with a single-period, single-product inventory model with several individual sources of demand. It is a multi-location problem with an opportunity for centralization. Two types of inventory system are considered in this paper: the decentralized system and the centralized system. The aim of this paper is to extend Eppen's model by adding the consideration of transportation cost to constitute a new inventory model. With this new inventory model we prove three theorems that include the results of Eppen's model.
229 citations
Journal Article•
TL;DR: In this article, the authors consider a single-period, single-product inventory model with several individual sources of demand and show that the expected holding and penalty costs in a decentralized system exceed those in a centralized system.
Abstract: This is a single-period, single-product inventory model with several individual sources of demand. It is a multi-location problem with an opportunity for centralization. The holding and penalty cost functions at each location are assumed to be identical. Two types of inventory system are considered in this paper: the decentralized system and the centralized system. The decentralized system is a system in which a separate inventory is kept to satisfy the demand at each source of demand. The centralized system is a system in which all demands are satisfied from one central warehouse. This paper demonstrates that, for any probability distribution of a location's demands, the following properties are always true: given that the holding and penalty cost functions are identical at all locations, (1) if the holding and penalty cost functions are concave functions, then the expected holding and penalty costs in a decentralized system exceed those in a centralized system, except that (2) if the holding and penalty cost functions are linear functions, and for any i≠j, Pij, the coefficient of correlation between the ith location's demand and the jth location's demand is equal to 1, then the expected holding and penalty costs in a decentralized system are equal to those in a centralized system.
218 citations
173 citations
TL;DR: In this article, the authors present linear programming in infinite-dimensional spaces and show that linear programming can be used to solve problems in the real world as well as in the virtual world.
Abstract: (1989). Linear Programming in Infinite-Dimensional Spaces. Journal of the Operational Research Society: Vol. 40, No. 1, pp. 109-110.
170 citations
TL;DR: A heuristic model is presented for determining the ordering schedule when an inventoried item is subject to deterioration and demand changes linearly over time, which produces a better solution than optimizing models.
Abstract: In this paper a heuristic model is presented for determining the ordering schedule when an inventoried item is subject to deterioration and demand changes linearly over time. While the optimizing model developed by researchers fixes the ordering interval and varies the ordering size, the heuristic permits variation in both replenishment-cycle length and the size of the order. As a result, the heuristic produces a better solution than optimizing models in the study presented here.
155 citations
TL;DR: A multiple-attribute error analysis is presented in order to make more precise discrimination among competing alternatives under uncertain environments and to measure the propagation of errors in the value of alternatives due to individual attribute rating and weight errors.
Abstract: The purpose of this paper is to present a multiple-attribute error analysis in order to make more precise discrimination among competing alternatives under uncertain environments. Measurements of (especially non-monetary) attribute ratings and assessments of attribute weights are often highly imprecise and subjective, yet most analytical methods lack provisions for handling imprecise data. This paper describes how to measure the propagation of errors in the value of alternatives due to individual attribute rating and weight errors. We also measure the errors in attribute weight due to imprecise preference information from the decision-maker.
124 citations
TL;DR: This paper examines in detail reasons for using constructively simple models in management science interventions and concludes that constructive simplicity in modelling is a robust strategy for effective interventions.
Abstract: This paper examines in detail reasons for using constructively simple models in management science interventions. Constructive simplicity is an objective concept describing the form and level of detail in a model. It is distinguished from the subjective concept of transparency, which relates to user-comprehension of a model. Usual arguments for constructive simplicity focus on model-building considerations such as model clarity, flexibility and convenience. Constructively simple models are also an efficient way of learning about decision situations. Client managers may prefer constructive simplicity not only as a convenient way of ensuring transparent models, but also for reasons related to motivation, time constraints, implementation and involvement of third parties. A principal conclusion is that constructive simplicity in modelling is a robust strategy for effective interventions.
113 citations
TL;DR: A new heuristic rule which compares favourably with the widely-used heuristic rules is developed, and the influence of network/resource characteristics on the performance of different heuristic Rules is investigated.
Abstract: The problem considered in this study is that of non-pre-emptive scheduling of the activities in a project network to minimize project duration under limited resource availabilities Various heuristic rules and optimization techniques have been applied to this problem, and comparisons of their effectiveness have been made in the literature However, no thorough investigation of the types of network and resource characteristics which play an underlying role in determining heuristic performance and which account for the variability of results has been made previously In this study, a new heuristic rule which compares favourably with the widely-used heuristic rules is developed, and the influence of network/resource characteristics on the performance of different heuristic rules is investigated
TL;DR: In this article, the authors present an Evolutionary Systems Design: Policy Making Under Complexity and Group Decision Support Systems (ESDS), which is an evolutionary approach to group decision support systems.
Abstract: (1989). Evolutionary Systems Design: Policy Making Under Complexity and Group Decision Support Systems. Journal of the Operational Research Society: Vol. 40, No. 11, pp. 1053-1054.
TL;DR: An alternative approach to an earlier model developed by other authors to formulate a problem of sequencing N jobs on M machines in a standard flow-shop involves substantially fewer variables, at the expense of a rise in the number of constraints.
Abstract: This paper presents an alternative approach to an earlier model developed by other authors to formulate a problem of sequencing N jobs on M machines in a standard flow-shop. The objectives of the model are to minimize makespan and flow-time. The new formulation involves substantially fewer variables, at the expense of a rise in the number of constraints. Practical limitations of both approaches are discussed.
TL;DR: In this paper, the authors presented the discounted cash-flow approach for the analysis of the optimal inventory policy in the presence of the trade credit, which permits a proper recognition of the financial implication of the opportunity cost and out-of-pocket costs in inventory analysis.
Abstract: This paper presents the discounted cash-flows (DCF) approach for the analysis of the optimal inventory policy in the presence of the trade credit. The DCF approach permits a proper recognition of the financial implication of the opportunity cost and out-of-pocket costs in inventory analysis. This approach also permits an explicit recognition of the exact timing of cash flows associated with an inventory system. As a result, the effect of the delayed payment is appropriately reflected in determining the optimal order size.
TL;DR: In this article, the potential savings made by semi-fixed or variable routes over fixed routes are estimated for standard problems, and the implications of these savings are then evaluated for a wholesale distributor.
Abstract: The standard vehicle-scheduling problem is deterministic, assuming all factors are known with certainty in advance of scheduling. In practice there are several areas which might contain uncertainty. This paper suggests ways of tackling these, but concentrates on problems where some customers do not need deliveries during a scheduling period. If the number of such customers is small, semi-fixed routes may be acceptable. As the number of customers omitted rises, there comes a point when rescheduling becomes preferable. The potential savings made by semi-fixed or variable routes over fixed routes are estimated for standard problems. The implications of these savings are then evaluated for a wholesale distributor.
TL;DR: The contributions in this book have a practical slant, showing how AI has been successfully applied to a wide spectrum of domains and tasks in aerospace, banking and finance, biotechnology, emergency services, law, manufacturing design and assembly, media and music, the military, operations management, personnel management, and retail packaging.
Abstract: From the Publisher:
All of the contributions in this book have a practical slant, showing how AI has been successfully applied to a wide spectrum of domains and tasks in aerospace, banking and finance, biotechnology, emergency services, law, manufacturing design and assembly, media and music, the military, operations management, personnel management, and retail packaging. They provide an excellent sampling of the types of applications coming on line. Systems architectures and development strategies are addressed along with tactical issues, payback data, and real benefits.
The applications include: An Intelligent Training System for Space Shuttle Flight Controllers. An Advisor for Financial Analysis of Automobile Dealerships. The Intelligent Banking System. An Intelligent Assistant for Foreign Traders. The PepPro Peptide Synthesis Expert System. MannTall: A Rescue Operations Assistant. An Expert System for Legal Consultation. CAN BUILD. A Knowledge-Based Integrated Circuit Design Critic. Times: An Expert System for Media Planning. Wolfgang: Musical Composition by Emotional Computation. MacPlan: A Mixed Initiative Approach to Airlift Planning. Naval Battle Management Decision Aiding. Planning the Discharging and Loading of Container Ships. The Ford Motor Company Direct Labor Management System. An Expert System for Rigid Plastic Food Package Design.
Herbert Schorr is Director of the USC Information Sciences Institute and Alain Rappaport is President of Neuron Data. Copublished with The AAAI Press.
TL;DR: A heuristic decision rule is derived for the replenishment of items with a linearly increasing demand rate over a finite planning horizon during which shortages are allowed.
Abstract: A heuristic decision rule is derived for the replenishment of items with a linearly increasing demand rate over a finite planning horizon during which shortages are allowed. When compared with the exact decision rule, the heuristic is found to incur negligible cost penalty for the numerical example which is given to illustrate the use of the heuristic.
TL;DR: The proposed method is a general-purpose algorithm which uses only one operation, the Gauss Jordan pivoting used in the simplex method, which appears to be faster than simplex, more general than stepping-stone and simpler than both in solving general TP.
Abstract: This paper re-examines use of the linear programming (LP) formulation to solve the transportation problem (TP). The proposed method is a general-purpose algorithm which uses only one operation, the Gauss Jordan pivoting used in the simplex method. The final tableau can be used for post-optimality analysis of TP. This algorithm appears to be faster than simplex, more general than stepping-stone and simpler than both in solving general TP. A numerical example illustrates the methodology. It is assumed the reader is familiar with simplex terminology.
TL;DR: This book provides the first unified and current view of the principal exact computational algorithms that have been developed to date for the analysis of product form queueing networks and suggests the existence of even more efficient algorithms that might be developed.
Abstract: In the last fifteen years queueing networks have come into widespread use as models of computer systems and computer-communication networks. Their popularity derives primarily from the particular class of product form queueing networks that make available a large variety of modeling features and for which a number of efficient computational algorithms have been developed. This book provides the first unified and current view of the principal exact computational algorithms that have been developed to date for the analysis of product form queueing networks.The authors cover both recent important advances such as the Recursion by Chain Algorithm (RECAL), Mean Value Analysis by Chain (MVAC), and the Distribution Analysis by Chain (DAC) algorithms, and established algorithms such as the Convolution Algorithm and Mean Value Analysis within the context of a unified theory based on the notions of decomposition and aggregation.The theory gives a useful general constructive methodology for the development of computational algorithms and unifies the seemingly unconnected developments that have taken place. It also provides intuitive insight into the problem of constructing efficient algorithms and suggests the existence of other even more efficient algorithms that might be developed.Adrian E. Conway is Senior Member of Technical Staff at GTE Laboratories Incorporated. Nicolas D. Georganas is Dean of the Faculty of Engineering at the University of Ottawa. "Queueing Networks: Exact Computational Algorithms" is included in the Computer Systems series, edited by Herb Schwetman.
TL;DR: In this paper, a mathematical programming model for the M-to-1 FBNDP is presented, and the proposed heuristic provides reasonable feeder-bus networks and consistent responses to "what if" questions.
Abstract: The potential for improving the cost-effectiveness of public transport operations by designing better integrated feeder-bus/rail rapid transit systems has been widely recognized. This paper defines the feeder-bus network-design problem (FBNDP) as that of designing a feeder-bus network to access an existing rail system. The FBNDP is considered under two different demand patterns, many-to-one (M-to-1) and many-to-many (M-to-M). We present a mathematical programming model for the M-to-1 FBNDP, and show that it can be generalized to the M-to-M FBNDP. The FBNDP is a large and difficult vehicle-routeing-type problem with an additional decision variable—operating frequency. A heuristic model is presented, which generalizes the ‘savings approach’ to incorporate operating frequency. The computational analysis shows that the proposed heuristic provides reasonable feeder-bus networks and consistent responses to ‘what if’ questions. A comparison indicates that the proposed heuristic provides solutions that are superior to manually designed networks. The advantages of this heuristic are particularly significant under variable demand.
TL;DR: Two types of algorithm are used—a simple ‘local improvement’ method, performed successively from randomly chosen starting points, and a ‘simulated annealing’ approach, which is found to give considerably better results than a deterministic method in current use.
Abstract: This paper addresses a problem common to all railway networks Given a fixed train timetable and locomotives (or other forms of traction) of various types, each train must be allocated a locomotive This paper examines the use of stochastic algorithms for such a problem Two types of algorithm are used—a simple ‘local improvement’ method, performed successively from randomly chosen starting points, and a ‘simulated annealing’ approach Both are found to give considerably better results than a deterministic method in current use, and the annealing approach is probably the better stochastic method
TL;DR: An alternative proof of the Quaddus result is offered, without relying on duality theory, and it is shown how quaddus' examples fall short of optimizing the total penalty.
Abstract: In a recent paper, Quaddus presents a linear programming analysis for assigning an optimal due date to n independent jobs. The criterion treated in the model is the minimization of total penalty cost, where, for each job, penalties are assessed on earliness, tardiness and due-date allowance. Quaddus considers job-dependent penalties, thereby generalizing models addressed by other authors, but neglects the sequencing aspect of the problem. As a consequence, the examples are not completely optimized. In this note we offer an alternative proof of the Quaddus result, without relying on duality theory, and we show how Quaddus' examples fall short of optimizing the total penalty.
TL;DR: In this article, four different methods of index-fund construction are described and applied to Japanese stock-market data, and the tracking abilities of the constructed funds, both in and out of sample, are compared and contrasted.
Abstract: An index fund is an investment vehicle which mimics a stock-market index and thus exhibits market risk only. Fund managers can passively invest in index funds and concentrate on actively managing the remainder of their funds. This paper looks in detail at the use of statistical selection methods in the construction of these funds. The measurement of the ability of these funds to track the underlying index is examined. Emphasis is placed on the relevance of the horizon of the investor to the choice of measure of tracking error. Four different methods of index-fund construction are described and applied to Japanese stock-market data. The tracking abilities of the constructed funds, both in and out of sample, are compared and contrasted.
TL;DR: It is shown that the optimal job sequence for the single-machine problem can be easily determined, and it is proved that the same optimal due-date result can be generalized to the parallel- machine problem.
Abstract: In this paper we consider the problem of scheduling a set of simultaneously available jobs on several parallel and identical machines. The problem is to find the optimal due-date, assuming this to be the same for all jobs. We also seek to sequence the jobs such that some are early and some are late so as to minimize a penalty function. For the single-machine problem, we present a simple proof of the well-known optimality result that the optimal due-date coincides with one of the job completion times. We show that the optimal job sequence for the single-machine problem can be easily determined. We prove that the same optimal due-date result can be generalized to the parallel-machine problem. However, determination of the optimal job sequence for such a problem is much more complex, and we present a simple heuristic to find an approximate solution. On the basis of a limited experiment, we observe that the heuristic is very effective in obtaining near-optimal solutions.
TL;DR: This paper presents examples of recently developed measures of flexibility and adaptivity for machines and groups of machines in a manufacturing setting.
Abstract: This paper presents examples of recently developed measures of flexibility and adaptivity for machines and groups of machines in a manufacturing setting The flexibility measures depend on the set of tasks to be done relative to a background task set, the relative importance of the tasks and the efficiency of machines in doing them The measures of adaptivity relate flexibility measures in different situations, usually at different points in time
TL;DR: Two solution approaches to dynamic location-routeing problems involve the determination of the least-cost sequence of depot, vehicle fleet and route configurations in a distribution system, over a given planning horizon are presented.
Abstract: Dynamic location-routeing problems involve the determination of the least-cost sequence of depot, vehicle fleet and route configurations in a distribution system, over a given planning horizon. This paper presents two solution approaches to such problems. The first is an exact method which is appropriate for small-scale problems. It consists of representing the problem by a suitable network and of solving to optimality an integer linear programme associated with the network. In the second approach, some of the system costs are approximated, and a global solution is then obtained by determining a shortest path on a directed graph. Under some hypotheses, this approach is suitable for large-scale problems. It is illustrated on a simple example.