ISSN:0228-6203    

DOI:10.1080/02286203.1981.11759745

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractThe recently proposed pseudo characteristic method of lines is applied to transient two -phase flow computations, A homogeneous equilib- rium flow model has been programmed for a single heated channel as a part of a code for transient analysis of pressurized water reactors based on the FORSIM simulation package, A variant including slip between the phases has also been tested. The conservation equation systems considered are hyperbolic and are written in characteristic form for a particular equation of state. lagrangian four-point upwind and upwind bias difference schemes as well as the Hermite 3,1 upwind formula have been used for equal spatial division. A standard flow-boiling problem and a reactor start up transient have been used to test the algorithm. The experience with different upwind discretization schemes and boundary approximations is discussed.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11759746

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractA general-purpose software tool has been developed to aid production planners in high-quantity assembly-line plants. The logic incorporated in the software employs smoothing techniques for a mix of products based on total cumulative man-weeks of work. It uses a graphic interface with the production planner to give him a number of smoothing options as well as to let him make any desired changes. The logic allocates the total work to each assembly line and produces a detailed weekly schedule for each product. It also presents numerical and graphic results in formats familiar to the planner to judge the suitability of the plans generated.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11759747

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractThis paper means to give some insight into the problematic of the design and operation of grain terminals. It gives a general description of a part of such a chain, namely an export terminal.A simplified model for such a terminal is presented. This model can be translated into a computer program using mainly discrete event simulation techniques.Effects of the arrival pattern of ships are numerically shown finally.This paper should be considered as part of an interim assessment of the results of a study in cooperation with GEM Consultants BV Rotterdam.The aim of this study is to achieve designs for more economical terminals for transhipment of grain and grain-derivatives.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11760454

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractIn certain inventory situations it makes sense to coordinate the control of a group or family of items in that a single major ordering (replenishment) cost is incurred if any item in the group is ordered (e.g. where the group of items are all ordered from the same suppli-er). A reasonable control system is a so-called can- order point or (S,c,s) system. In such a system a group replenishment is enacted when any item 1 hits its must- order point, s1. Enough is ordered of item i to raise its inventory position to its order-up-to-level, S1. At the same time any other item J with a low enough inventory level, namely at or below its can-order point ej, is included in the group order so as to raise its Inventory position to Sj. The mathematical analysis of such a system, e.g. the computation of the expected service level of a particular item, is extremely complicated. In this paper we discuss the use of simulation to estimate two common measures of service. Particular attention is devoted to ascertaining the amount of variance reduction achieved through the use of Conditional Monte Carlo.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11760455

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractThis paper discusses the joint use of analytic and simulation techniques to study the statistical characteristics of selected inventory models. The concept followed was to use analytic methods insofar as possible and then use simulation after that.We begin with a simple inventory model having zero procurement lead times and exponential demand, and derive means and variances of reorder, holding, and shortage costs. When we introduce non-zero procurement lead times, we find it necessary to use simulation. The statistical problem then involves computing the size of simulation samples required to estimate the holding and shortage costs with specified precision and confidence.The statistical results obtained both analytically and by simulation are summarized, along with the validation test made of the simulation data. The test results were quite satisfactory.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11760456

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

SummaryThis paper compares the cost-effectiveness of 4 heuristics to determine the ordering policy in inventory systems with dynamic stochastic demand. The Least Unit Coot method, Part Period balancing, the Silver Meal Algorithm and the Wagner-Whitin Algorithm were adjusted for the stochastic demand case, whereafter their performance was simulated over a 24 period horizon. Also in a stochastic environment the Uagner-Whitin Algorithm turned out to result in significantly lower total costs than the other heuristics.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11760457

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractIn der vorliegenden Arbeit wird ein diskretes, ereig-nisorientiertes, stochastisches Slmulationsmodell be-schrieben, das in der Logistlk angewandt wird. Es 1st in SIMULA geschrieben.In der Logistik 1st die optimale ErsatzteiIbe-messung ein wichtlges Problem. Unser Simulationsmo-dell versucht seiche gegebenen Bemessungen zu bever- ten. Das heisst, dass das Modell den ganzen Repara-turvorgang von defekten, identischen Objekten 1n ei- nem hierarchischen, mehrstufinen Netz von Servlce-stellen nachbildet. Die durch das ModelI zu untersu- chenden Grossen s1nd die Ersatzteillagerbestande der Servicestellen. Je nachdem wie diese Lagerbestdnde sich wahrend der Simulation verdndern, lassen sich Aussagen Uber die GUte der vorgenommenen Bemessung machen.In the present work we describe a discrete, event-driven, stochastic simulation-model in the field of logistics. It is written in SIMULA.In logistics the optimum inventory level for spare parts is an important problem. Our simulation model tries to assess such a given inventory level. For that reason, the model reproduces the whole pro-ceeding of repair of damaged, Identical objects in a hierarchical, multicomponent net of service-stations. The quantities to examine are the stocks of spare parts of the service-stations. These stocks will change during the simulation and the change gives us indications about the goodness of the inventory level.

ISSN:0228-6203    

DOI:10.1080/02286203.1981.11760458

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor