Study of the behaviour of flexible production systems using neural nets

Owing to high development and acquisition costs, production systems require very detailed analysis for pre-design specifications, and an adjustment in operating philosophies. Detailed simulation models are one of the most important instruments to achieve this goal; normally the simulator must be custom-built, based on an accurate study of the specific industrial problem. The proposed management and economical analysis uses mathematical meta-models obtained from experimental designs produced by the simulator; today the detail level and precision required is very high, so these kinds of meta-model operate very close to their limit. Here we present a new methodology based on artificial neural networks that produces new types of meta-models which can correctly represent complex industrial systems. In this work we propose an application of this methodology together with a detailed analysis of the model development phase to highlight the potential of this instrument.     

FORRIDGE - Principles of good practice in material flow

The post World War II Industrial Revolution has driven production away from the old 'economies of scale' to the new 'economies of scope'. Apparently Japanese led, the associated roots of present good practice on material flow can be traced back in the USA to Jay Forrester and in the UK to Jack Burbidge. Specifically, in the supply chain scenario, Forrester exposed the importance of system structure in relating and integrating information flow with material flow. Similarly Burbidge led the way in exploiting cycle time reduction, synchronization of orders throughout the chain, simplified product structures, and streamlined component flows. This paper unites their contributions to material flow engineering and shows how present day system design methodologies incorporate their ideas on best practice. These principles are particularly relevant to the product delivery process (PDP) which governs material flow in supply chains.     

Rough-cut capacity planning for remanufacturing firms

Capacity planning is a critical element of any successful production planning and control system. A method of rough-cut capacity planning is developed, based on the bill-of-resources approach, that can be used to plan for capacity required for firms in a remanufacturing including overhaul repair operations environment. The modified bill-of-resources approach developed takes into account two major stochastic elements inherent in this environment; probabilistic material replacement factors and probabilistic routing files. A detailed example from an actual repair overhaul operation is presented to illustrate the technique.     

An assessment of GRAI Grids and their use in the Strathclyde Integration Method

The purpose of this paper is to present a critical assessment of GRAI Grids as a tool for improved manufacturing integration. GRAI Grids, a key component of the GRAI approach, form an integral part of the Strathclyde Integration Method SIM for manufacturing integration. The contribution of the paper is thus to provide a 'third party' view of the effectiveness of GRAI Grids as a modelling tool. The paper presents a brief overview of the GRAI approach, concentrating particularly on the Grids, and an overview of SIM, showing how GRAI Grids are used. The main section of the paper presents an assessment and critique of GRAI Grids. Several benefits and limitations of the Grid as used in SIM and some suggestions for extensions are presented. The paper concludes that the use of the GRAI Grid, within a methodology, provides a unique insight into the behaviour and design of manufacturing information systems and that those who criticize the technique perhaps do so from a lack of awareness of its concepts, principles and advantages.     

Measuring and analysing supply chain schedule stability: A case study in the automotive industry

Final assembly plants send material schedules to first-tier suppliers who in turn send schedules to second-tier suppliers and so on through the multiple tiers of the supply chain. A key cost driver for the supply chain is a schedule characteristic termed stability. The Total Quality Management approach is applied to improve schedule stability in the supply chain of a large vertically integrated automotive manufacturer. A measurement described, actual stability results are provided, the causes of instability are listed, and some corrective actions are specified. Results indicate that schedule stability can be improved without damaging the performance of other measures such as inventory and customer responsiveness. and analysis process is     

TQM: Some issues for deliberation

In this note, the author puts forth some fundamental but generic issues arising from evolving theories and practices of TQM and suggests an agenda for furtherance of research.     

A simulation analysis of the impact of family configuration on virtual cellular manufacturing

Past research has shown that it is possible to simultaneously achieve the setup efficiencies of traditional cellular manufacturing systems and the routeing flexibility of a job shop by viewing cells not as permanent, physical structures, but as temporary, 'virtual' entities. This research demonstrates that the advantages of virtual manufacturing cells can be obtained over a range of part family configurations. In particular, virtual cellular manufacturing is robust to changes in the number and size of families being processed. Further, the research shows that the benefits can be obtained under setup conditions impartial to a family-oriented part environment.     

Sources of occupational stress: An examination of British prison officers

Abstract

The purpose of this paper is to identify the major sources of occupational stress experienced by British prison officers and to examine their effects on overall job stress and job satisfaction. Eighty-one officers from HM Prison, Maidstone, took part in a questionnaire study, and three main findings emerged. First, lack of stiff and resources were ranked as the most likely sources of stress, and areas of the prison where confrontations with inmates were most likely to occur were ranked as the most stressful locations. Second, officers who reported the highest levels of job stress overall had the lowest job satisfaction and the greatest wish for more emphasis on control and security of inmates. Third, when the sources of stress were factor-analysed and used to predict overall job stress and job satisfaction, using multiple regression, the sìngle most important predictor of job stress was found to be the factor labelled 'confrontations with inmates' and, for dissatisfaction with the job, it was 'poor morale and resentments'. The paper discusses the theoretical implications of the findings.     

Catastrophe Risk Models for Evaluating Disaster Risk Reduction Investments in Developing Countries

Major natural disasters in recent years have had high human and economic costs, and triggered record high postdisaster relief from governments and international donors. Given the current economic situation worldwide, selecting the most effective disaster risk reduction (DRR) measures is critical. This is especially the case for low‐ and middle‐income countries, which have suffered disproportionally more economic and human losses from disasters. This article discusses a methodology that makes use of advanced probabilistic catastrophe models to estimate benefits of DRR measures. We apply such newly developed models to generate estimates for hurricane risk on residential structures on the island of St. Lucia, and earthquake risk on residential structures in Istanbul, Turkey, as two illustrative case studies. The costs and economic benefits for selected risk reduction measures are estimated taking account of hazard, exposure, and vulnerability. We conclude by emphasizing the advantages and challenges of catastrophe model‐based cost‐benefit analyses for DRR in developing countries.