基于“前港后厂”模式的进口铁矿石采购物流成本优化

作为钢铁产量大国，国内铁矿石资源品位低、开采难度大、选矿成本高，需要大量进口国外优质铁矿石，导致钢铁企业采购物流成本居高不下；长期大批量远距离的铁矿石海运历史，促使了我国"港-钢"企业的发展紧密相连。因此，本文基于"前港后厂"模式，构建了以船型、供应商和接卸港的选择为变量，以最小化铁矿石采购物流成本为目标的组合优化模型。运用免疫遗传算法和MATLAB进行求解与仿真验证，结果表明"前港后厂"模式较传统模式在优化采购物流系统上更优，为推行"前港后厂"模式提供了理论依据。     

基于活动──组织流程图的业务过程重构方法

将原有的支持BPR的活动流程图和组织流程图结合起来,提出一种基于活动—组织流程图的、人机交互式的企业业务过程重构方法．该方法利用图的邻接矩接和可达矩阵,可以方便地找出业务流程中的不合理部分,从而为大规模系统的业务过程改造提供了一种有效的工具．方法应用于某钢铁公司的物资管理系统的流程改造,取得了满意的效果．     

Optimal replacement strategies in network infrastructures under quality penalties

As a consequence of liberalization, electric utilities have developed different asset management strategies with the aim of reducing total maintenance costs by prolonging replacement cycles. A cost-minimizing network operator has to optimize the trade-off between costs for early replacement and quality penalties he faces in the case of outages (due to a resulting higher number of failures). The basic purpose of this paper is to identify the optimal decisions for a network operator under output-based quality regulation and to determine the main drivers for his decisions. In order to derive general insights, an analytical framework is chosen for this paper. This work builds on the foundations of optimal maintenance and replacement strategies as developed across Operations Research, Production Economics and Engineering Production Theory. As main results we are able to analytically derive optimal replacement strategies for network components depending on the characteristics of their failure distributions linked to the equipment’s cost, respective replacement cost, and quality penalties.     

Optimal and Acceptable Technical Facilities Involving Risks

Economic cost-benefit optimization of technical facility requires suitable "life saving cost" and/or an appropriate acceptance criterion if human life and limb are at risk. Traditionally, acceptance criteria implicit in codes of practice, standards, or regulations for well-defined fields of application are calibrated against past and present practice. This is all but satisfying. It is unclear whether present rules are already optimal. Extrapolations into new fields of application are extremely difficult. Direct cost-benefit analysis is proposed as an alternative. Based on the recently proposed "life quality index" (LQI), a rational acceptance criterion and so-called life saving cost are derived. The classical life quality index is reviewed, modified, and imbedded in modern economics theory. The results are then applied to technical facilities. The relation between optimization and the LQI-based acceptance criterion is discussed. The relevant economics literature is reviewed with respect to discount rates applicable for long-term investments into risk reduction. They should be as low as possible according to a recent mathematical result. Modern economic growth theory decomposes the output growth rate into the rate of time preference of consumption and the rate of economical growth multiplied by the elasticity of marginal utility of consumption. It is found that the rate of time preference of consumption should be a little larger than the long-term population growth rate. The public benefit rate (output growth rate) on the other hand should be smaller than the sum of the population growth rate and the long-term growth rate of a national economy, which is around 2% for most industrial countries. Accordingly, the rate of time preference of consumption is about 1%, which is also intergenerationally acceptable from an ethical point of view. Given a certain output growth rate there is a corresponding maximum financial interest rate in order to maintain nonnegativity of the objective function at the optimum. Finally, a simple demonstration example is added.     

A human - computer interactive approach based on activity - section analysis for BPR

In any business process reengineering (BPR) project, a thorough understanding of various tasks and activities of the organization is required. Very often this idea is captured using a simple flow chart or static representation diagram. The weakness here is that the process design complexity is not adequately represented by the use of flow charts, and this allows for limited human-computer interaction during the process design and analysis. In this paper, we propose an enhanced flow chart approach; the concept of activity-section flow chart to support BPR, which is a combination of the existing activity flow chart and section flow chart. Using this approach, a human-computer interactive model for BPR is developed. This model can identify the unreasonable activity loops and excessive business rounds between sections by the adjacent and reachable matrices. Via the human-computer interaction, the process can be revised by human experience. This approach provides an efficient tool for BPR of large-scale systems. It has been applied to the material supply management system of an iron and steel works, and satisfactory results have been achieved.     

Energy modelling in practice: an application of spatial programming

This paper is focused on the practical aspects of energy modelling through the presentation of a case study involving spatial programming to analyze the problems of electric utilities in the northeastern United States. Emphasis is on the resolution of client-analyst problems in the context of a series of real world policy problems to which the model was applied. Attention is also given to the conceptual problems of applying linear programming techniques to location problems where capacity expansion takes the form of discrete rather than continuous units.     

Analysis of Local Acceptance of a Radioactive Waste Disposal Facility

Like many other countries in the world, Korea has struggled to site a facility for radioactive waste for almost 30 years because of the strong opposition from local residents. Finally, in 2005, Gyeongju was established as the first Korean site for a radioactive waste facility. The objectives of this research are to verify Gyeongju citizens' average level of risk perception of a radioactive waste disposal facility as compared to other risks, and to explore the best model for predicting respondents' acceptance level using variables related to cost-benefit, risk perception, and political process. For this purpose, a survey is conducted among Gyeongju residents, the results of which are as follows. First, the local residents' risk perception of an accident in a radioactive waste disposal facility is ranked seventh among a total of 13 risks, which implies that nuclear-related risk is not perceived very highly by Gyeongju residents; however, its characteristics are still somewhat negative. Second, the comparative regression analyses show that the cost-benefit and political process models are more suitable for explaining the respondents' level of acceptance than the risk perception model. This may be the result of the current economic depression in Gyeongju, residents' familiarity with the nuclear industry, or cultural characteristics of risk tolerance.     

HERESY IN DECISION ANALYSIS: MODELING SUBSEQUENT ACTS WITHOUT ROLLBACK *

When making a current decision, like choosing an experiment, a subject will often take into account “subsequent acts” which he does not yet commit to. Common practice requires modeling through preposterior analysis, which treats one act as certain, conditional on the intervening information modeled. This is not logically necessary since the same expected utilities could be obtained by properly conditioning utility on any selection of events (including subsequent acts). The subject could assess utility marginal on subsequent acts or conditional on subsequent acts treated as uncertain events. The preposterior model is a special case of the latter where conditioning information is sufficiently modeled to imply subsequent act probabilities of zero or one. This paper argues that attempts at preposterior modeling are often unsuccessful and have critically flawed much current practice in decision analysis. Simpler approaches such as the “acts-as-events” model are intrinsically less dependent on restrictive assumptions and have been successfully applied to many real-world decisions.     

基于两阶段博弈模型的钢铁行业碳强度减排机制研究

减少温室气体排放,高耗能行业将承担主要的减排任务,不同的减排机制对减排任务在不同技术水平的企业间分配和减排成本影响不同,而且对企业竞争力和社会福利有影响。本文构造了一个两阶段动态博弈模型,以两个代表性钢铁企业(东部和西部)为研究对象,来考察在完成一定减排目标前提下,政府设置统一碳税和差异化碳税对减排成本、社会经济福利、企业竞争力等的影响。实证结果表明:统一碳税下,钢铁行业产量降幅较小,行业减排任务分解的更加平均,西部钢铁企业竞争力损失较小;差异税下,实现既定减排目标的减排成本较小;社会经济福利损失较小,且随着减排目标的不断升高,两种碳税下社会经济福利损失之差有拉大的趋势;东部钢铁企业竞争力提高幅度较大,但对西部钢铁企业的负面影响十分明显。因此,在碳税机制设计时应充分考虑不同税率模式对减排任务分解、钢铁行业产量、社会经济福利以及企业竞争力的具体影响,需要在社会成本较低和个体企业的竞争力受影响较小之间进行权衡。     

基于上市公司数据的中国钢铁产业产能效率分析

运用规模报酬可变的DEA模型和Malmquist指数方法,从产能和产出的角度对27家上市公司2000～2009年产出效率进行了分析,综合考察了这一时期中国钢铁产业的产能效率状况。研究结果表明,2000～2009年中国钢铁产业技术效率和动态效率都较低,存在大量的生产能力闲置。其中,较大规模企业技术进步明显,但存在较为严重的劳动力松弛;较小规模企业动态效率较高,但技术变动能力相对较差。由此,中国钢铁产业应充分利用现有的生产能力,以有利于技术效率的提升;保持产业政策的平稳以及增强企业的适应性,以有利于动态效率的提升。     

Dynamic Preference for Flexibility

We consider a decision maker who faces dynamic decision situations that involve intertemporal trade‐offs, as in consumption–savings problems, and who experiences taste shocks that are transient contingent on the state of the world. We axiomatize a recursive representation of choice over state contingent infinite horizon consumption problems, where uncertainty about consumption utilities depends on the observable state and the state follows a subjective Markov process. The parameters of the representation are the subjective process that governs the evolution of beliefs over consumption utilities and the discount factor; they are uniquely identified from behavior. We characterize a natural notion of greater preference for flexibility in terms of a dilation of beliefs. An important special case of our representation is a recursive version of the Anscombe–Aumann model with parameters that include a subjective Markov process over states and state‐dependent utilities, all of which are uniquely identified.     

Study on Compatibility between Converters and Casting Machines for Daily Steelmaking and Continuous Casting Scheduling

In this paper, daily production scheduling is studied based on the Third Steelmaking Plant of Wuhan Iron and steel corporation (WISCO). To make sure the daily production plan is feasible, method of casting gToup is established, and the compatibility between two converters and three continuous casting devices in the Third Steelmaking Plant of WISCO is analyzed. The process flow chart of daily production scheduling is given in this paper. Then, algorithms and procedures for the simulation of daily production plan is developed. Using the actual data from the Third Steelmaking Plant, the feasible daily steelmaking plan and cast plan are given. The plan contains 7 groups of cast plan, figured out 54 converters, and a- bout 13,500 tons steel.     

Infrastructure in Developing and Transition Countries: Risk and Protection

This article examines two possible strategies for financing post-disaster infrastructure rehabilitation in developing and transition countries: relying on ex ante financing instruments (including insurance, catastrophe bonds, and other risk-transfer instruments) and ex post borrowing or credit. Insurance and other ex ante instruments will increase a country's stability, especially if the government authorities have a difficult time borrowing or otherwise raising funds after a major disaster; however, these instruments have an opportunity cost and can reduce the country's economic growth potential. The cost-benefit tradeoff is therefore one between economic growth through infrastructure investment and added solvency and stability for the economy. This article develops a model to illustrate this tradeoff. The model, which views the infrastructure of a developing or transition country as a nondiversifiable portfolio that generates returns, can provide a basis for evaluating alternative financing options depending on the country's objectives in terms of growth, solvency, and stability.     

Monopoly Union Wage Setting and Evaluation of Public Projects: An Intertemporal General Equilibrium Approach

ABSTRACT This paper contains cost-benefit rules for public projects in a small open economy with a tradeable and non-tradeable sector, where wage setting is done by a representative household. The interpretation, with regard to traditional trade union theory, is in terms of a general equilibrium version of a monopoly union model. The intertemporal character of the model makes it possible to consider public projects which involve the creation of infrastructure that improves the future productivity of both labour and capital. A special feature of the model is the introduction of endogenous investment behaviour. However, since private investment is optimally adjusted in the initial equilibrium, envelope properties guarantee that first-order projects will only have second-order repercussions through changed investment behaviour, which means that indirect changes in private investment do not enter the project evaluation rules for small projects.     

基于相关系数的钢材需求量组合预测

近年来我国钢材消费量和产量大幅提升,在1997～2006年的10年里分别增长了308%和367%,虽然同期内国内铁矿石产量也增加了119%,但仍无法满足钢铁工业的需求,对外依存度从28.5%提升到51.8%。在对钢材以及铁矿石消费量的预测实践中,由于不同的预测方法能够提供不同的有用信息,其预测精度往往也存在差异,为了分散预测的风险,文章采用基于相关系数的组合预测方法对我国未来的成品钢材需求量进行预测,并对预测结果进行了深入分析。结果表明,基于相关系数的组合预测模型在预测准确性和适应性方面均能得到一定改善,能很好地对钢材需求量进行科学、有效的预测。     

Cost-benefit analysis of training— An appraisal

With the phenomenal growth in investment in training, there has been an increasing concern with evaluating the training programmes in terms of their economic efficiency—sometimes adopting the cost-benefit approach. However, since behavioural and psychological factors are so central to training, all evaluative studies have come across the problems of quantifying the costs and benefits. These apart, there are problems in enumerating the spillover and long term effects of training programmes, in assuming a discount rate and in identifying the economic life of the training project.

Recent studies purporting to have used cost-benefit analysis have failed to grapple with a number of issues making them closer to conventional financial appraisals. In this paper the limitations of such evaluations, the difficulties in making a cost-benefit analysis of training investment and its feasibility with varying situations is discussed. The article will amply point out to the corporate decision-maker the problems in using cost-benefit analysis and the training contexts where it is feasible.     

炼钢热轧一体化生产与物流计划模型及求解

合理的板坯与热轧卷库存、缩短产品的生产周期、降低能源消耗、按合同交货以提高客户满意度已成为钢铁生产管理的要求.为了降低生产与物流成本,本文针对炼钢与热轧生产及其衔接方式的特点,考虑能力和两个阶段冲突约束条件下构建生产与物流计划层次的一体化模型.分析了无能力约束和允许延迟条件下热轧批量的极点特征,对原问题采用Dantzi...     

Technical Progress,Life of Capital and Employment

This paper examines the hypothesis of a quickening of capital replacement, triggered by the acceleration of technical progress. We present a microeconomic model of replacement processes inspired by the “unbalanced growth” school, highlighting the role of productivity in determining the growth path. The model distinguishes between two types of enterprise, stagnant and progressive, on the basis of productivity trends and shows that prolonged acceleration in the rate of technical progress may be sufficient reason for a rational entrepreneur to make replacements earlier, thus approaching a system of continuous restructuring. We then discuss the main theoretical implications for aggregate employment and the fundamental questions of measurability of the effects. To this end, we undertake an empirical test of aggregate data for the manufacturing sector in four leading economies (the United States, France, Germany, the United Kingdom) from 1970 to 1991. We estimate labour demand functions in which the traditional explanatory variables are supplemented by proxies that capture the effect of a shortening of the life of capital equipment (the replacement rate and the ratio between depreciation and gross fixed capital formation). The empirical evidence confirms the shortening of the average lifetime of capital and is consistent with the main implications of the microeconomic model. The results show, at least indirectly, a negative correlation between an increase in speed of technical progress and the growth of employment.     

DYNAMIC DISAGGREGATE CHOICE MODELS,WITH AN APPLICATION IN TRANSPORTATION

A standard assumption of disaggregate mode-choice models is that an individual faced with a choice among several available alternative transportation modes compares their utilities. These utilities are almost always expressed as a linear composite measure of various perceived benefits which are assumed constant. However, the individual's perceptions change as he learns, acquires new habits, or adapts to different physical, economic, and social circumstances. In order to account for these changes, two dynamic models of model-choice behavior are developed herein. These two models are based on two common postulates. (1) One alternative is preferred over another only if the absolute difference in their utilities exceeds a positive constant; otherwise, the decision maker is indifferent toward the two alternatives. (2) If an alternative is preferred, it will be chosen with certainty. In the indifference state, the individual is postulated to randomly choose one of the two alternatives (Model 1) or choose the same alternative as was most recently chosen (Model 2). Choice probabilities derived from these two models are shown to differ from those obtained using the conventional logit model. If there is a strong loyalty toward a mode, the logit model underestimates its choice probability when that mode is less attractive than the competing mode. The results are illustrated using numerical examples.     

A cost model for deferred state life test plans with replacement

This paper presents a cost model for the deferred state life test plan, which is one of the lot-by-lot acceptance sampling plans by attributes. In most sampling plans, the decision to accept or reject a submitted lot depends only on the sampling test results of the lot concerned; other information will not be considered. Deferred state life test plan is a sampling plan which uses information about subsequent lots for making decisions to accept or reject the current lot. The objective of this paper is to evaluate the total test cost of using the deferred state life test plan to see whether the use of this life test plan can reduce the total cost of the sampling test. In order to calculate the expected total test cost of the deferred state life test plan, a cost model is developed for the deferred state life test plan with replacement. Also, a cost comparison is made between a deferred state life test plan and a comparable military standard sampling plan which offers the same level of producer's and consumer's protection. The results show that the deferred state life test plan consistently reduces the overall cost of sampling tests over a variety of test conditions.