摘要:

Obtaining the desired service-level is one of the most important problems in inventory control. The term ‘service-level’ has been interpreted in several ways. This paper presents a survey of the three most common service measures and the mathematical calculations pertaining to each.

ISSN:0020-7543    

DOI:10.1080/00207548108956694

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The paper defines batch or job shop production and reviews the functions of production planning and production control in a job shop manufacturing situation. It argues that the separation of planning and control has resulted in the artificial isolation of the sequencing problem in job shop research. It attempts to redefine the production control function for a job shop, now called job shop control, and discuss the activities it involves. The major decision-making problems associated with job shop control are highlighted and an objective function of costs to aid in management decision making is evolved.

ISSN:0020-7543    

DOI:10.1080/00207548108956695

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This paper presents equations for determining the bounds on maximum throughput capacity, the length of conveyor required for accumulation, and the time for a queue to dissipate after blocking the flow on a live roller and on a zero pressure accumulation conveyor. Input flow in ease-feet per minute is assumed to be known and deterministic but may be either less, or greater, than the capacity of the output metering belt.

ISSN:0020-7543    

DOI:10.1080/00207548108956696

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

When a project network consists of activities that have many alternatives and pairwise compatibility relationships, the task of finding feasible project plans and then finding the optimal project plan is a difficult one. This paper employs compatibility matrix approach and derives statistical relationships for the estimation of the mean number of feasible alternative plans and the estimation of standard deviation of number of such plans using statistical sampling and simulation. The estimates are obtained as functions of parameters related to the configuration of compatibility matrices and are independent of specific problems. Many situations in practice are amenable to 'solution’ by the compatibility matrix approach. The method explained in this paper has been applied to real-world project planning problems. Capital budgeting, process planning, manufacturing and production policy are some of the other areas where the results obtained through this research will prove useful.

ISSN:0020-7543    

DOI:10.1080/00207548108956697

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Adapting to changes over time is a primary point in any forecasting system. The quicker the adaptation the better the resulting forecasts. This is very important in computerized forecast-inventory control systems that manage thousands of parts. In such environments, it is difficult, if not impossible, to have all forecasts reviewed for possible changes in behaviour. This paper proposes two modifications to Winters' exponentially weighted moving-average model that provides improved forecasts for time series exhibiting seasonal behaviour. A set of tests is conducted to evaluate the performance of the original and modified Winters s models using 25 time series. The results indicate that average forecast errors have been reduced for the test series. The paper concludes with a discussion of the suitability of the proposed modifications under certain conditions.

ISSN:0020-7543    

DOI:10.1080/00207548108956698

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In this paper, a theoretical model is proposed to describe the probability density functions of the random positions of grains on the wheel surface based on the interference of grooves by different grains. It also describes an algorithm for the theoretical simulation of both transverse and longitudinal surface profiles generated during fine surface grinding.

ISSN:0020-7543    

DOI:10.1080/00207548108956699

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This paper provides the statistical analysis to obtain the functional dependence of the radial distribution parameter on grinding conditions by comparing the power spectra of the simulated and experimental profiles. A numerical technique to evaluate the power spectral density and generation of surface profile with all random possibilities of interaction of grooves is also presented. It is found that the radial distribution parameter is linearly related to table speed and depth of cut in fine grinding. Results indicate that the power spectra of simulated and experimental profiles are in close agreement.

ISSN:0020-7543    

DOI:10.1080/00207548108956700

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This paper reports the existence of interrelationships among technological and operational variables pertaining to paced assembly lines. These variables are average cycle time, average number of workers, average number of work elements per station, average distance between workers, length of line, and average weight of product. The findings in the form of regression equations are based on a mail survey of 254 companies in the United States. The potential value of such equations lies in the fact that they represent empirical yardsticks which a company might use for diagnostic purposes in its own operations. For example, some interesting ‘ballpark’ comparisons might be obtained by a firm by simply inserting actual data into the regression equation for its particular product classification and observing how closely the result approximates the norm. This study was exploratory in nature and suggests several areas for further investigations.

ISSN:0020-7543    

DOI:10.1080/00207548108956701

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The individual effects of system configuration, relative stage position and buffer capacity allocation in automatic transfer line systems were investigated through computer simulation experiments. The breakdown and repair rates used in this study were 1/400, 1/200, 1/50 and 1/20 respectively. Steady-state responses on the production rate, in-process average stock and mean delay time were statistically analysed using the fixed effects analysis of variance model and Duncan's multiple range test. A table of preferred system designs with respect to each individual factor and response was developed as a useful guide for design purpose.

ISSN:0020-7543    

DOI:10.1080/00207548108956702

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The assignment of n facilities to n locations, with the objective of minimizing the total cost of the design, is known as the facilities design problem. For a problem of size 𝓃, there are 𝓃! feasible solutions, which can be represented by a frequency distribution of total costs. Recent statistical analyses have indicated that these distributions can be adequately described as gamma, and for many practical purposes the log normal or normal distributions give good approximations. The absolute mean of all the 𝓃!assignments can be easily calculated.

ISSN:0020-7543    

DOI:10.1080/00207548108956703

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor