Tax-Adjusted Replacement Models

The 1984 UK Finance Act introduced changes in tax legislation with consequences for both capital and revenue expenditure on plant. The one- and two-cycle rent models for capital equipment replacement and the infinite-cycle discounted-cost model are extended here to incorporate the new tax features. A specific replacement problem is used as the basis of an analyis of the sensitivity of the optimal replacement period to parameters. Whilst all these models are consistently insensitive to the new tax legislation, there is no consistency across models with respect to which parameters dominate choice of optimal replacement period.     

Balancing stocks, flexible recipe costs and high service level requirements in a batch process industry: A study of a small scale model

Process industries often obtain their raw materials from mining or agricultural industries. These raw materials usually have variations in quality which often lead to variations in the recipes used for manufacturing a product. Another reason for varying the recipe is to minimize production costs by using the cheapest materials that still lead to a satisfactory quality in the product. A third reason for using recipe flexibility is that it may occur that not all materials for the standard recipe are available. If variations in supply and demand are large, keeping sufficient safety stock to cope with these variations may incur prohibitive high costs. This means that the costs of keeping safety stock should be balanced with the costs of sometimes using more expensive recipes. The question now is for what situations and to what extent the use of recipe flexibility is justified. In this paper we study this question by means of a small scale model. For this simple situation we derive a decision procedure to balance safety stock costs and flexibility costs. This procedure is applied to a range of different situations, that are characterized by a set of parameter values, in order to determine for which situations recipe flexibility should be used.     

Industrial petrochemical production planning and expansion: A multi-objective linear programming approach

This paper considers a strategic model planning for the petrochemical industry. It concerns with the expansion in a firm producing multiple products in several regions of a country. The expansion of the existing facilities and the new ones are considered. It also exists a large amount of interdependencies among the firm’s products, because the output of one particular plant can be used as an input to the production of another plant in the same or different regions and to satisfy the final demand. The decision makers involved in the planning process should identify several objectives. Then, multiple objective programming is used for making trade-offs among the economic and operational factors considered. To define the interval criteria weights into the model we utilized the Analytic Hierarchy Process to bring them closer to the decision makers preferences. This work was sponsored by the Institut National Polytechnique de Toulouse, France, when the author was Associate Professor at the Département Génie des Systèmes Industriels.     

Integrated planning of transportation and recycling for multiple plants based on process simulation

By-products accrue in all stages of industrial production networks. Legal requirements, shortening of primary resources and their increasing prices make their recycling more and more important. For the re-integration into the economic cycle the scope of common supply chain management is enlarged and so-called closed-loop supply chains with adapted and new planning tasks are developed. In process industries this requires a detailed modelling of the recycling processes. This is of special relevance for operational planning tasks in which an optimal usage of a given production system is envisaged. This contribution presents an integrated planning approach for a real-world case study from the zinc industry to achieve such an adequate process modelling. We consider the planning problem of a company that operates four metallurgical recycling plants and has to allocate residues from different sources to these recycling sites. The allocation determines the raw material mix used in the plants. This blending has an effect on the transportation costs and the costs and revenues of the individual technical processes in the recycling plants. Therefore in this problem transportation and recycling planning for multiple sites have to be regarded in an integrated way. The necessary detailed process modelling is achieved by the use of a flowsheet process simulation system to model each recycling plant individually. The models are used to derive linear input–output functions by multiple linear regression analyses. These are used in an integrated planning model to calculate the decision-relevant input and output flows that are dependent upon the allocation of the residues to the recycling sites. The model is embedded in a decision support system for the operational use. An example application and sensitivity analyses demonstrate and validate the approach and its potentials. The approach is transferable to other recycling processes as well as to other processes in process industries.     

Evaluation of three production planning procedures for the use of recipe flexibility

Process industries often obtain their raw materials from mining or agricultural industries. These raw materials usually have variations in quality, which often lead to variations in the recipes used for manufacturing a product. Another reason for varying the recipe is to minimize production costs by using the cheapest materials that still lead to a satisfactory quality in the product. A third reason for using recipe flexibility is that it may occur that at the time of production not all materials for the standard recipe are available. In earlier research we showed under what conditions the use of this type of recipe flexibility should be preferred to the use of high materials stock to avoid materials shortages. We also showed that the use of recipe flexibility to account for material shortages can be justified if the material replenishment leadtime is long, the demand uncertainty is high and the required service level is high. In this paper we assume that these conditions are satisfied and we investigate three different production planning procedures that make use of recipe flexibility to cope with the uncertainty in demand and supply. We assume that the customer order leadtime is much smaller than the material replenishment leadtime, and therefore demand uncertainty is high. The optimal procedure optimizes material use over a planning horizon equal to the material replenishment leadtime, taking into account the customers orders and knowledge of the distribution function of future demand. The deterministic procedure also optimizes the material use over the material replenishment leadtime, but it assumes a deterministic demand level for unknown orders. The simplest, myopic procedure optimizes material use over only the accepted customer orders. These three procedures are investigated via an experimental design of computer simulations of an elementary small scale model of the production planning situation. The results show that the optimal procedure outperforms the other two procedures. Furthermore, for a realistic cost structure in feed industry under certain circumstances the use of the optimal procedure may lead to a 4% increase in profit. However, this improvement must be weighted against the cost incurred by the operational use of this complex procedure. Based on these considerations and the numerical results in this paper, we may expect that for some situations in practice the use of the simplest myopic procedure, optimizing material use only over the available customer orders, will be justified from an overall cost point of view.     

The keyskills agenda: exploring implications for mathematics

As part of a broader research objective concerned with identifying the range of employer defined skill profiles that characterize workplace performance, this paper examines skill contexts for Application of Number, one of six UK defined Key Skills similar to Australian defined Key Competencies. Following the construction of questionnaires, grounded in the Analytic Hierarchy Process, applications of the instrument in both the UK and in Australia produced a ratio scale of priorities within the Key Skills area. This enabled a specification of the relative balance between classical competencies, e.g. facility with pen and paper calculations and emerging competencies demanded by the effective use of ICT. Relevance to workplace learning, including the transition from school to employment, and related aspects of mathematics education are discussed. Among the research outcomes is that spreadsheets are assuming a pre-eminent position and that this is an overriding priority for each defined activity and at each job level.     

Stochastic programming based capacity planning for semiconductor wafer fab with uncertain demand and capacity

Capacity planning is a challenging problem in semiconductor manufacturing industry due to high uncertainties both in market and manufacturing systems, short product life cycle, and expensive capital invest. To tackle this problem, this paper proposes a scenario-based stochastic programming model which considers demand and capacity uncertainties via scenarios, where the overall equipment efficiency is employed to describe the uncertain capacity for the first time. Based on the decentralized structure of tool procurement, production, stockout, and inventory decision-making processes, recourse approximation strategies are presented with varying degree of information share. The computational experiments show that the resulting tool set is robust enough to cope with the changes in capacity with the expected profits being maximized for different scenarios, and the scheme can generate pretty good solutions in reasonable computational time.     

Dynamic entry deterrence in the UK pathology services market

This paper describes work on a dynamic model of entry deterrence applied to the UK National Health Service (NHS) market for pathology services. The model, based on a game theoretical framework, is concerned with decision support applications. Presented in this paper is a case study analysis of a geographical region in which a provider of pathology services is concerned at the prospect of being exposed to competition from a new entrant. The incumbent provider may undertake strategic investments to create a stock of knowledge and goodwill with the intention of dissuading others from entering the market. The effect of a new entrant is modelled as perturbation of a pre-existing stable Nash-Cournot equilibrium in an oligopolistic market, and is influenced by market forces subject to Government regulation. The original contribution of this study is to identify the nature of these potential strategic investments and their interaction with cash flows. Recent historical data and managerial analysis are used to characterise market growth. An estimate of the incumbent provider's market share which is at risk can be found by examining the local geographical distribution of providers and purchasers of pathology services. On the basis of this analysis we propose a method for obtaining the strategic investment profile which minimises the total investment required to deter entry.     

Agency and structure: a social simulation of knowledge-intensive industries

Modern knowledge-intensive economies are complex social systems where intertwining factors are responsible for the shaping of emerging industries: the self-organising interaction patterns and strategies of the individual actors (an agency-oriented pattern) and the institutional frameworks of different innovation systems (a structure-oriented pattern). In this paper, we examine the relative primacy of the two patterns in the development of innovation networks, and find that both are important. In order to investigate the relative significance of strategic decision making by innovation network actors and the roles played by national institutional settings, we use an agent-based model of knowledge-intensive innovation networks, SKIN. We experiment with the simulation of different actor strategies and different access conditions to capital in order to study the resulting effects on innovation performance and size of the industry. Our analysis suggests that actors are able to compensate for structural limitations through strategic collaborations. The implications for public policy are outlined.     

基于政府驱动的新能源汽车产业合作创新演化博弈研究

自战略性新兴产业提出以来,战略性新兴产业一直飞速发展,而新能源汽车产业作为战略性新兴产业的重要组成部分,越来越受到政府的重视。本文基于演化博弈理论建立汽车制造企业与学研机构的演化博弈模型,分别在市场机制与政府鼓励机制下,用数值仿真展示参数取值变化对演化结果的影响。研究发现,政府对于技术研发的支持力度、合作创新双方利益分配系数、政府采购力度、合作双方约定的罚金以及合作创新成本与额外收益的关系对新能源汽车合作创新有影响。     

Some Systems Aspects of Strategic Planning

This paper is concerned with the strategic planning process and the contribution that analysis can make to it. It develops a conceptual model of the strategic planning process based on the traditional control system model and identifies a number of basic elements of the process. Four groups of analytical tools are presented and their relevance to the planning process discussed. It is suggested that tools from the different groups may be used concurrently at different parts of the process, although the use of analytical tools in some parts of the planning process is not well established. Finally the role of the analyst in the overall planning process is discussed.     

Concurrent engineering: a competitive strategy for process industries

Concurrent Engineering (CE) is a systematic approach to the integrated, simultaneous design of both products and their related processes, including production. A number of research reports are available in the literature to deal with CE and its applications in manufacturing industries. However, the application of CE in Process Industries (PI) has not received enough attention from researchers and practitioners for improving productivity and quality. To use CE effectively in process industries requires accuracy of data and a common architecture. In PI, the products are processed with minimal interruptions in any one production run or between production runs of products that exhibit process characteristics, such as liquids, fibres, powders and gases. The general characteristics of this industry add value to materials by mixing, separating, forming, or chemical reactions. PI often initiate their flow with only a few raw materials and subsequently process a variety of blending and resplitting operations. Nevertheless, there are many common characteristics such as material and information flow between manufacturing and PI. This indicates the application areas of CE in PI and hence to improve the competitiveness of PI in terms of flexibility and responsiveness. An attempt has been made in this paper to study how CE can be utilized to design products, production system, and production planning and control (PPC) system for improving productivity and quality in PI.     

A raw material shortage model of the Finnish chemical industry

At the beginning of 1975 the Federation of the Finnish Chemical Industry and the University of Helsinki, Department of Computer Science, set up a project to develop a mathematical model to be used as a planning tool during accidental raw material shortages in the Finnish chemical industry. The model has been designed, programmed, and tested. The main part of the system consists of a linear programming model, which is used to answer “what-if” questions.This paper describes the model, the programs and the main problems encountered in the design process. The present version of the system can solve problems involving at most 100 firms, 400 products, 400 types of raw materials and 200 technical or policy constraints.     

中国上市公司资本结构行业差异的实证研究--统计检验、成因分析及合理性研究

本以国内部分上市公司为样本，利用多种统计分析方法从行业差异角度对其资本结构进行实证研究，目的是检验国内上市公司资本结构行业差异的显性，并分析其成因及行业资本结构选择的合理性。研究结果表明：我国不同行业上市公司资本结构存在显差异，且公用事业与其他行业的差异最为突出；行业的竞争程度及风险性、资产结构、资产运营能力及行业的成长性会在较大程度上导致行业差异的存在；我国上市公司普遍存在行业收益风险和资本结构不相匹配的现象。同时提出了有关政策建议。     

考虑货架存放期的经济批量排产问题的求解

在化工、造纸、制药、钢铁等工业生产中，一台设备或一条生产线可以生产多种产品的情况很常见。在生产中，如何安排各类产品的生产顺序以及生产数量显得十分重要。这类问题通常称作经济批量排产问题，这类问题是生产库存中的经典问题。本文研究的经济批量排产问题考虑了产品货架存放期因素，针对以往研究的不足，本文提出用批量变动方法求解该类问题，由计算结果显示，按照这种排产方法花费的成本要低于其他两种经济批量排产问题常用的方法。     

CFD modelling of thickeners at Worsley Alumina Pty Ltd

Computational fluid dynamics (CFD) modelling of process unit operations is a tool that is being used increasingly by mineral processing industries to reduce operating and capital costs and increase throughputs.Worsley Alumina first became involved with CFD modelling through support of the AMIRA Thickener Technology Project 266A in 1994, and subsequent extension projects in which CSIRO has been developing validated CFD models of thickener operation. The CSIRO Division of Minerals has been involved with CFD modelling since 1984 mainly on high temperature furnace applications and has been developing multi-phase thickener models since 1992. The benefits of obtaining a better understanding of flow patterns in thickeners using this modelling method became obvious and projects commenced in the third quarter of 1995 to utilise the CSIRO expertise. Projects have been ongoing almost continuously since that time. The CFD modelling was verified using tracers to measure actual flow patterns in a settler. Once verification had been achieved the CFD model was used to test innovative changes in design aimed at achieving higher throughputs and improved operation. These innovative changes when implemented on the full plant gave results similar to the CFD model predictions and resulted in improved process stabilisation, reduced chemical costs and very large savings in capital requirements for our major expansion that has just been completed. There are a number of assumptions made in the CFD model and these are discussed in detail in the paper together with details of individual CFD modelling projects and cost benefits achieved from completed projects.     

On a game in manufacturing

We analyse a non-zero sum two-person game introduced by Teraoka and Yamada to model the strategic aspects of production development in manufacturing. In particular we investigate how sensitive their solution concept (Nash equilibrium) is to small variations in their assumptions. It is proved that a Nash equilibrium is unique if it exists and that a Nash equilibrium exists when the capital costs of the players are zero or when the players are equal in every respect. However, when the capital costs differ, in general a Nash equilibrium exists only when the players' capital costs are high compared to their profit rates.     

An optimization-based decision support system for strategic planning in a process industry: the case of aluminium company in India

We describe how a generic multi-period optimization-based decision support system (DSS) can be used for strategic planning in process industries. The DSS is built on five fundamental elements—materials, facilities, activities, storage areas, and time periods. It requires little direct knowledge of optimization techniques to be used effectively. Results based on real data from an aluminium company in India demonstrate significant potential for improvement in profits. We conclude with a comparison of similar studies in two other process industries.