Liquidity Constrained Markets Versus Debt Constrained Markets

This paper compares two different models in a common environment. The first model has liquidity constraints in that consumers save a single asset that they cannot sell short. The second model has debt constraints in that consumers cannot borrow so much that they would want to default, but is otherwise a standard complete markets model. Both models share the features that individuals are unable to completely insure against idiosyncratic shocks and that interest rates are lower than subjective discount rates. In a stochastic environment, the two models have quite different dynamic properties, with the debt constrained model exhibiting simple stochastic steady states, while the liquidity constrained model has greater persistence of shocks.     

Procurement process: Decision by exclusion and pairwise comparisons

Two case studies illustrate multicriteria decision making techniques frequently used in procurement practice: least-cost sufficient performance and weighted utility optimization. Both techniques have defects and are rarely robust. Decision by exclusion and pairwise comparisons is proposed as a third approach which eliminates inferior alternatives by generalized forms of minimum performance requirements established under multicriteria framework. It is more robust and maintains high level of accountability.     

A pairwise interchange algorithm for parallel machine scheduling

This paper considers the problem of non-preemptive scheduling n tasks on m identical parallel processors to minimize makespan for simultaneous arrivals. Based on a pairwise interchange method, an efficient algorithm ispresented which is able to give a near-optimal schedule in a short time through suitable pairwise interchange between tasks, after an initial solution is constructed. The behaviour of the algorithm is discussed. Testing results prove its high performance in comparison with available simple heuristic procedures. Finally, the algorithm is generalized for the problems of non-identical processors and non-simultaneous arrivals.     

A qualitative perspective to deriving weights from pairwise comparison matrices

Deriving weights from pairwise comparison matrices (PCM) is a highly researched topic. The analytic hierarchy process (AHP) traditionally uses the eigenvector method for the purpose. Numerous other methods have also been suggested. A distinctive feature of all these methods is that they associate a quantitative meaning to the judgemental information given by the decision-maker. In contrast, the verbal scale used in AHP to capture judgements does not associate such a quantitative meaning. Though this issue of treating judgements qualitatively is recognized in the extant literature on multi-criteria decision making, unfortunately, there is no research effort so far in the AHP literature. Deriving motivation from the application of data envelopment analysis (DEA) for deriving weights, it is proposed in this paper that DEA models developed to deal with a mix of qualitative and quantitative factors can be used to derive weights from PCMs by treating judgements as qualitative factors. The qualitative DEA model is discussed and illustrated in this paper.     

R&D portfolio selection by using qualitative pairwise comparisons

A new multicriteria decision aid, QualScal, is applied to the problem of selecting an extramural Fisheries R&D portfolio in the Ministry of Agriculture, Fisheries and Food. QualScal has been developed for the situation where the characteristics of the decision alternatives cannot be readily quantified. The decision-maker is only required to state either indifference or preference for each pair of the alternatives. A map representing the preference structure of the decision maker is produced with the aid of an enhanced version of the traditional nonmetric multidimensional scaling procedure, capable of scaling disjoint subsets of alternatives. Averaged results for the group of decision-makers facilitate a discussion to determine a mutually acceptable portfolio.     

在两资源约束项目环境中的关键链管理

Theory ofConstraint(TOC)强调以系统的观点来进行项目管理,它在项目管理中的运用被称为关键链管理(CCPM).它通过项目的关键链,并利用缓冲器来进行项目管理.文献[1]解决了在单资源约束下的关键链管理.本文在两资源约束下,以优化项目工期为目标,以关键链为基础,对资源进行分类,然后提出了分阶段进行资源规划的算法,从而推进了关键链管理在多资源环境下如何运用的研究工作.     

Constrained Forecasting: Some Implementation Guidelines

Constrained forecasting has become a popular approach to the complex task of predicting future sales. Mixed performance results have been obtained by companies employing constrained forecasting systems software packages which probably reflects the lack of any clear system implementation guidelines. A number of important operational parameters such as the number of product families, criterion used to define product families, number of system levels, etc. must be specified. This study reports on an investigation of two of these parameters: product group size and appropriate grouping criterion. Different tests are performed with the constrained forecasting system and compared to a traditional forecasting approach using product data from the Cummins Engine Company of Columbus, Indiana.     

A Model for Resource Constrained Production and Inventory Management

We present a general model for multi-item production and inventory management problems that include a resource restriction. The decision variables in the model can take on a variety of interpretations, but will typically represent cycle times, production batch sizes, number of production runs, or order quantities for each item. We consider environments where item demand rates are approximately constant and performing an activity such as producing a batch of a product or placing an order results in the consumption of a scarceresource that is shared among the items. Some examples of shared resources include limited machine capacity, a restriction on the amount of money that can be tied up in stock, orlimited storage capacity. We focus on the case where the decision variables must be integer valued or selected from a discrete set of choices, such as when an integer number of production runs is desired for each item, or in order quantity problems where the items come in pack sizes containing more than one unit and, therefore, the order quantities must be an integer multiple of the pack sizes. We develop a heuristic and a branch and bound algorithm for solving the problem. The branch and bound algorithm includes reoptimization procedures and the heuristic to improve its performance. Computational testing indicates that the algorithms are effective for solving the general model.     

在单资源约束项目中的关键链管理

Dr.Goldratt于1986年提出了Theory of Constraint(TOC),强调以系统的观点来进行项目管理。TOC在项目中的运用被称为关键链管理(CCPM),它着眼于项目的关键链,并利用缓冲器来控制项目进程。本文在单资源约束下,以TOC为核心思想,提出了一个进行关键链管理的方法,从而改进了TOC在项目管理中的可操作性。     

关于有约束存贮模型的一个问题

现有教科书对有约束的存贮论问题的解决方法是用无限制存储论优化模型加上Kuhn-Tucker限制条件。实际上,这样的结果并非最优解,在实际应用中,它存在着订货次数过多、资源利用率低、总费用过高等缺点。本文在指出现有教科书中有约束存贮模型的不足之所在,并试图用反证法予以证明。     

The Comparative Statics of Constrained Optimization Problems

This paper develops and applies some new results in the theory of monotone comparative statics. Let f be a real‐valued function defined on R^l and consider the problem of maximizing f(x) when x is constrained to lie in some subset C of R^l. We develop a natural way to order the constraint sets C and find the corresponding restrictions on the objective function f that guarantee that optimal solutions increase with the constraint set. We apply our techniques to problems in consumer, producer, and portfolio theory. We also use them to generalize Rybcsynski's theorem and the LeChatelier principle.     

Sales territory alignment for sparse accounts

A sales territory alignment problem for sparse accounts where travel time is a major component of the salesman's worktime is presented and analyzed. The objective is to minimize total driving distance of salesmen while equalizing driving distance between salesmen. A mixed integer programming formulation and an interactive heuristic algorithm in the context of a practical application are discussed.     

Constrained Optimization Approaches to Estimation of Structural Models

Estimating structural models is often viewed as computationally difficult, an impression partly due to a focus on the nested fixed‐point (NFXP) approach. We propose a new constrained optimization approach for structural estimation. We show that our approach and the NFXP algorithm solve the same estimation problem, and yield the same estimates. Computationally, our approach can have speed advantages because we do not repeatedly solve the structural equation at each guess of structural parameters. Monte Carlo experiments on the canonical Zurcher bus‐repair model demonstrate that the constrained optimization approach can be significantly faster.     

受限制投资组合机会成本的实证研究

通过对只能投资于股票和只能投资于债券2种情况下的投资组合的机会成本的计算,研究了受限制情况下所产生效用损失和风险厌恶程度对机会成本的影响。计算中选用上证综合指数、深圳成分指数、中信国债指数、中信企债指数和银行间7日债券回购利率的5年期月度数据,运用向量自回归的方法估计下期组合的期望收益和收益的联合概率分布,并运用Quasi-Newton最优化方法来求得最优投资组合,从而求出机会成本。     

动态联盟中企业建模的Meta-Model

虚拟组织的两个主要组成 :1 )虚拟的办公环境 ,如个体之间不受地理位置限制的电子通讯交流方式和个体之间基于信息技术支持的文件存储、检索或数据处理等系统 .2 )功能虚拟化 ,发展自己的核心业务能力 ,弱项实行外包 ( outsourcing) .因此 ,信息技术和信息系统的有效支持是虚拟企业的重要特征之一 .如何在构建虚拟企业动态联盟的企业建模时 ,考虑整体的信息系统构架值得研究 .文章利用战略依赖 /原理模型等面向目标 ( goal-oriented,GO)的分析方法—OO( object-oriented)方法的延伸 ,研究了虚拟企业动态联盟中企业建模的 Meta-Model,该模型为动态联盟间的信息系统构架提供了建模的基础     

Dynamic Programming and Hill-Climbing Techniques for Constrained Two-Dimensional Cutting Stock Problems

In this paper we propose an algorithm for the constrained two-dimensional cutting stock problem (TDC) in which a single stock sheet has to be cut into a set of small pieces, while maximizing the value of the pieces cut. The TDC problem is NP-hard in the strong sense and finds many practical applications in the cutting and packing area. The proposed algorithm is a hybrid approach in which a depth-first search using hill-climbing strategies and dynamic programming techniques are combined. The algorithm starts with an initial (feasible) lower bound computed by solving a series of single bounded knapsack problems. In order to enhance the first-level lower bound, we introduce an incremental procedure which is used within a top-down branch-and-bound procedure. We also propose some hill-climbing strategies in order to produce a good trade-off between the computational time and the solution quality. Extensive computational testing on problem instances from the literature shows the effectiveness of the proposed approach. The obtained results are compared to the results published by Alvarez-Valdés et al. (2002).     

Lifecycle Pricing for Installed Base Management with Constrained Capacity and Remanufacturing

Installed base management is the policy in which the manufacturer leases the product to consumers, and bundles repair and maintenance services along with the product. In this article, we investigate for the optimal leasing price and leasing duration decisions by a monopolist when the production and servicing capacity are constrained. The effect of diffusion of consumers in the installed base is considered, with the ownership of the product resting with the monopolist during the product lifecycle. The monopolist operating the installed base jointly optimizes the profits from leasing the product/service bundle along with maintenance revenues and remanufacturing savings. We formulate the manufacturer's problem as an optimal control problem and show that the optimal pricing strategy of the firm should be a skimming strategy. We also find that the effect of remanufacturing savings on the pricing decision and the length of the leasing duration changes significantly depending on the duration of the product's lifecycle. If the product lifecycle is long and remanufacturing savings are low, the firm should offer a shorter leasing duration, whereas if the remanufacturing savings are high, the firm should optimally offer a higher leasing duration. In contrast, if the time duration of the product lifecycle is low and remanufacturing savings are low, the firm prefers to offer a shorter leasing duration, whereas if the remanufacturing savings are high, the firm should optimally have a longer leasing duration. The article also shows that if the production capacity is small, the manufacturer increases the leasing duration. If the production capacity is very small, the manufacturer sets the leasing duration to be equal to the product lifecycle and does not use remanufacturing.     

多资源受限条件下工程集成管理优化问题研究

本文建立了多资源受限条件下工程集成管理优化的模型,该模型的求解属于国际上公认的NP-hard难题之一,利用基于优先权的编码技术使得模型的求解成为可能,提出同时具有惯性权重和限定因子参数的改进版本微粒群算法,编制其matlab求解源程序,运用在以管道水平定向钻穿越工程为实例的集成管理优化模型中,微粒群算法程序在求解过程表现出了高效的搜索能力,获得了满意的优化结果。最后,着重讨论了在微粒群算法参数设计中微粒个体意识与集体意识的比较分析和微粒群种群规模与协同搜索能力的关系。     

Mobilizing organizational alignment through strategic human resource development

This study examines the pivotal role of strategic human resource development (SHRD) in mobilizing organizational alignment. Using case study methodology, I trace the implementation of core competency development as a companywide SHRD initiative. The rationale for introducing core competency development as an organization-wide strategy was to enhance talent acquisition, development and retention. The operating environment (global market, industry space) and firm-specific factors (e.g. demographics and new leadership) accelerated the adoption of SHRD. Internal stakeholder orientation towards SHRD and the role of human resource development (HRD) in facilitating the implementation were also identified as critical factors. Organizational alignment emerged as an implicit consequence, while patterns of misalignment created barriers towards achieving the full benefits of SHRD. Furthermore, HRD displayed a high level of resourcefulness to become a strategic asset in the organization. I argue that the relevance and power of HRD lie in its ability to engage and respond to stakeholder expectations and involvement in organization change efforts.     

Risk alignment in health care quality and financing: optimizing value

How should health care best consolidate rational cost control while preserving and enhancing quality? That is, how can a system best optimize value? A limitation of many current health management modalities may be that the power to control health spending has been expropriated from physician providers, while they are still fully responsible for quality. Assigning responsibility without authority is a significant predicament. There are growing indications that well-organized, well-managed groups of high quality physicians may be able to directly manage both types of risk-quality and financial. The best way to optimize responsibility and authority, and to control financial and quality risks, is to place such responsibility and authority within the same entity.