An industrial application for total productivity optimization

Abstract. This paper presents four strategies for total productivity optimization of a real-life manufacturing company. These strategies are developed to attain overall growth, cost reduction, upgrading of technical efficiency and management effectiveness. Such strategies have been modelled mathematically by using a nonlinear mathematical programming approach. The model base and the data base used in implementing the strategies can serve as decision support to management for optimizing total productivity.     

On vendor part delivery dates in a stochastic assembly system

This paper describes the development of a model for the determination of optimal mean part delivery dates in a stochastic assembly system for the objective of minimizing the expected cost of subassembly and part inventory. Parts are assembled at each station to a subassembly. The part delivery and processing times at assembly stations follow known probability distributions. An approximate solution technique based on the optimization of individual stations in isolation is developed. The approximation applies a correction factor, as a function of the variability in part delivery and processing time, cost parameters and number of stations, to the decisions from the single station solutions to compensate for interdependence between stations. Results indicate that this is an effective approach and yields good near-optimal solutions with very little computational effort. Insights regarding the effect of the type of distribution used, random processing times, variance of the distribution used and cost parameter values on part delivery dates are also reported.     

Development of an integrated information management model: A case of textile industry

For past two decades many organisations have tried to implement integrated information management systems for better production management based on co-ordination of information and therefore activities of different departments. Although Enterprise Resource Planning systems have been in the market for the past decade, many industries find it difficult to implement such systems due to the amount of work involved in streamlining the documentation, customisation and of high costs reported in implementation. An attempt is made through this paper to propose an integrated model, which can be easily understood by production personnel, with specific emphasis on the textile sector.     

Supply chain management: a supplier perspective

A new way of researching into supply chain management is introduced by adopting a supplier perspective. Details are given of mixed integer linear planning and simulation models. The planning model takes into consideration firm and forecast orders (customer's forecast purchasing orders) and the behaviour of the supplier's suppliers and suppliers' subcontractors. The simulation model takes into account the dynamic behaviour of the supply chain and includes the planning production behaviour of a supplying company based on the planning model. The supplier manager can use the simulation model to determine what kind of parameters most affect company performances and then propose new management rules. Quantitative results that prove the benefits of integrating forecast orders for an aeronautic supplier have been provided.     

New developments in generative BOM processing systems

Abstract

The principle of generative bill-of-material (BOM) processing systems is that different BOMs belonging to different product variants can be represented by a single, so-called source BOM. The BOM processing systems comprise additional data structures which hold information on the relationships between product characteristics of parent product variants and component product variants, and on the relationships between characteristics of a parent product variant and its BOM data. These relationships allow the automatic generation of the individual BOM of each represented product variant. There are several alternative ways of implementing a generative BOM processing system. The oldest concept known is the variant BOM concept. This concept provides a relatively simple solution to deal with large varieties of final product variants. However the concept has a number of drawbacks such as the representation of product variety at lower levels in the product structure and data redundancy which hampers data maintenance. In this paper an improved concept for generative BOM processing systems is introduced and described: the generic BOM concept. The generic BOM concept does not focus on representing final product variants only, but takes a broader view towards representing any range of product variants at any level in the product structure. This starting point solves a number of draw-backs implied by the variant BOM concept but it also requires new definitions of BOM relationships and the introduction of new data structures to support the generation of individual BOMs.     

Modular design of integrated databases in production management systems

Abstract

Complexity is a serious problem with respect to the application of information technology in the field of production management. This paper presents an overview of the more fundamental problems encountered and proposes a solution for some of those problems in the form of modular decomposition of the conceptual database structure. It is argued that the complexity of information systems is closely connected to the complexity of the organization. Therefore a condition for the realization of integrated information systems for production management is a simplification of the organizational structure by way of defunctionalization and the forming of autonomous units.     

Pearson-Tukey Three-Point Approximations Versus Monte Carlo Simulation

Accuracy of the Pearson-Tukey three-point approximation is measured in units of standard deviation and compared with that of Monte Carlo simulation. Using a variety of well-known distributions, comparisons are made for the mean of a random variable and for common functions of one and two random variables. Comparisons are also made for the mean of an assortment of risk-analysis (Monte Carlo) models drawn from the literature. The results suggest that the Pearson-Tukey approximation is a useful alternative to simulation in risk-analysis situations.     

A rational approach to career change

Recently, the number of physicians who have been interested in alternative careers has vastly increased. Many physicians express dissatisfaction with clinical practice, but they are uncertain about which nonclinical options are appropriate for them. Pursuing a different career after many years of studying and practicing medicine can seem like an overwhelming task. In this article, the author briefly outlines a decision-making process that can be used in analyzing career options and suggests some careers that have provided challenging opportunities for physicians.