摘要:

AbstractThe most important problems for corporate planners in industry are planning the cash flow to ensure growth and helping the company to see itself, explicitly, as a portfolio and to assist the development of that portfolio. Planners have dismissed the role of operational research groups and O.R. techniques and basically simple techniques, usually developed by general consultants, have made a considerable impact, particularly "Boston" concepts of portfolio management. Planning processes are dominated by human judgement and the work of Godel is invoked to suggest that the use of better models to influence these corporate decisions is a forlorn hope. O.R. groups should concentrate on helping to solve perceived and real problems after seeking to display alternatives better, rather than to optimise. They should concern themselves more with improving the quality of presentation and ensuring the clarity of basically simple messages.

ISSN:0160-5682    

DOI:10.1057/jors.1979.188

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractIt is the engineer's natural tendency to build into gas supply systems, security against mechanical failure. This can be done either by the provision of spare capacity in alternative means of supply or by the duplication of the less reliable items of equipment. However, such expenditure to protect customers against rare events can be expensive and often may not appear justifiable when compared with other weather security criteria already established in the gas industry.The paper describes the development of a methodology for maintaining consistency of security expenditure within the industry. The measure of added security accruing from a project was chosen to be the expected quantity of gas saved from non-supply. The problems associated with placing a value on unsupplied demand are discussed, and a valuation method derived from existing weather security expenditure is described. Some examples of the evaluation of projects for added security are given. The main conclusion reached was that a single criterion could be derived which was useful in evaluating the various engineering schemes for added security.

ISSN:0160-5682    

DOI:10.1057/jors.1979.189

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractThis paper deals with the problem of modifying a transportation network so as to fit it with existing demand. A set of procedures were applied to the replanning of medium-sized town bus routes in several case-studies; the chosen approach, which is the result of five years research applied in about 10 towns in France, is described and results are presented and discussed for two cases.

ISSN:0160-5682    

DOI:10.1057/jors.1979.190

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractThis article describes the work done to determine age limits for preventive replacements and overhauls in tramcar maintenance, where opportunities are provided by a failed component or an essential overhaul. A brief review of existing literature is also presented and two pair-wise suboptimal preventive replacement policies are considered. These policies are applicable to any "n" component system with subassemblies, where the cost of dismantling and assembling the various sub-units is of the same order as the cost of new parts. The results of a search to find more economical control limits are also presented.

ISSN:0160-5682    

DOI:10.1057/jors.1979.191

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractA revised mathematical programme is presented which reduces the number of rows and columns in the Linear Programming formulation of thep-Median Problem. The revised formulation reduces both the computer space required and computational time allowing the solution of large problems while still guaranteeing optimality. Computational experience with the new formulation is presented.

ISSN:0160-5682    

DOI:10.1057/jors.1979.192

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractThis paper shows that the adaptive filtering and forecasting techniques proposed by Makridakis and Wheelwright can be viewed as approximations to a more precise filtering method in which the Kalman filter is applied to a dynamic autoregressive model which is a special case of the models of Harrison and Stevens. The correct "learning" or "training factors" are shown to be data-dependent matrices rather than scalar constants.

ISSN:0160-5682    

DOI:10.1057/jors.1979.193

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractRobustness analysis has not previously incorporated explicitly the reactive response of other decision makers to the action of the initial decision maker. This note presents an extension of robustness analysis to incorporate this response of the decisional environment.

ISSN:0160-5682    

DOI:10.1057/jors.1979.194

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

ISSN:0160-5682    

DOI:10.1057/jors.1979.195

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

ISSN:0160-5682    

DOI:10.1057/jors.1979.196

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

ISSN:0160-5682    

DOI:10.1057/jors.1979.197

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor