摘要:

In a previous paper the author has studied some properties of the minimum cost control schemes using np-charts. The process model involves nine independent data parameters whose values have to be estimated before an optimum np-chart can be determined. Since errors in estimation often occur in practice, the present paper investigates the extent to which these errors affect the optimality of the control procedure. Four parameters are found to have negligible effect, three to have moderate effect, and two to have critical effect. Rased on these results, a discussion is presented on the practicality of the economic approach.

ISSN:0020-7543    

DOI:10.1080/00207547708943125

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This paper describes a production control plan which may be -used in a shop whose product line consists of numerous items which vary extensively in their demand pattern.

ISSN:0020-7543    

DOI:10.1080/00207547708943126

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Trained subjects performed a simple assembly task under self-paced and machine-paced working conditions. Work cycle times, respiratory intervals and cardiac R—R intervals were recorded continuously throughout 2 hours of unpaced and 2 hours of paced work of the same rate as the subject's mean unpaced performance. The two kinds of work were shown to be physiologically different, not in the direction physiological changes, but in their general levels and rates of change. The results indicated that the unpaced work imposed a higher load upon the subject than the paced work. It is also indicated that the organism may be prepared in advance for the work under unpaced conditions, while it seems to be ‘driven’ by the machine under paced conditions, and works with a kind of momentary ‘physiological lag’.

ISSN:0020-7543    

DOI:10.1080/00207547708943127

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This paper presents an analysis of tool-wear data mainly from the view-point of flank wear. Mechanism of wear of cemented carbide tools is considered to be of two main types: (i) mechanical interaction, with adhesion-transfer type being the main cause and mechanical abrasion of secondary importance; (ii) thermochemical type, which is considered to be a diffusion process closely associated with temperature. A theory is presented on the prediction of volume of tool wear, and experimental results are presented and compared with theory.

ISSN:0020-7543    

DOI:10.1080/00207547708943128

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

An adaptive control system is proposed in which a given amount of tool wear is allowed per operation. The objective of the control system is to machine a certain feed distance in the minimum tune using no more than the wear allowed and working within the conventional adaptive control constraints. The average rate at which the operation progresses can thus be regulated by appropriately setting the wear target. The adaptive control system has been applied to the control of a lathe performing a simple bar turning operation. An on-line computer receives transducer responses, calculates and issues feed and speed corrections. The optimization policy requires the tool wear rate to be estimated while cutting and in this work the estimation was made from the cutting process variables including the tool-work thermocouple voltage. Workpiece disturbances in the form of hardness changes were introduced and the experimental responses of the control system to these disturbances are presented. The success of estimating wear rate on a sample of the controlled tests is also presented.

ISSN:0020-7543    

DOI:10.1080/00207547708943129

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In laboratory experiments on the rapid partial annealing of cold-worked mild steel sheet, the experimental results have been used to derive an empirical model, interrelating the mechanical properties of the sheet with different variables selected in order of their effects on the particular mechnaical property. The validity of these process model relationships was tested by predicting the mechanical properties coreesponding to each of the experimental conditions included in the model and comparing them with the actual experimental values. This comparison revealed that only the 0-2% P.S. and the T.S. equations satisfactorily predict properties to an acceptable degree of accuracy. The scope and limitation of this type of empirical model are discussed in terms of application and the difficulties associated with precisely defining the pertinent process or material variables. Finally, it is demonstrated how the equations can be used to optimize the different process variables to achieve a given property level or combination of properties.

ISSN:0020-7543    

DOI:10.1080/00207547708943130

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Because of the increasing importance of ultradeep drills in oil exploring, the casing optimization is of increasing relevance. First, the structure of the problem will be discussed. Second, a model based on the directional convex maximum principle will be introduced. Then we discuss an (exact) method which generates minimal material costs and, finally, we compute the numerical solution by taking a simple example. Compared with models which are based on dynamic programming our model will have substantially fewer numerical requirements.

ISSN:0020-7543    

DOI:10.1080/00207547708943131

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0020-7543    

DOI:10.1080/00207547708943133

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor