对关键链法的几个认识误区

关键链法是在约束理论基础上发展起来的一种新型项目进度管理技术,已有较多文献对其进行了介绍,但也存大一些认识误区。从关键链法的基本思想入手,在关键链与关键路径、时间缓存量的确定方法、时间缓存与虚工序、计划与区间计划等几个重要认识误区做了澄清和解释。     

Identifying inventory problems in the aerospace industry using the theory of constraints

In the aerospace industry, where each component is time-critical, many operation management tools are applied to improve material management efficiency. By using the theory of constraints (TOCs), this study diagnoses the undesirable effects (UDEs) of material management systems and identifies root problems or conflicting material management actions. In the second step, via UDEs, this study constructs a current reality tree (CRT) to identify a company's material management objectives and requirements, and the actions it takes to meet these objectives. In addition, the UDEs and CRT are applied to redesign the future reality tree (FRT) to develop strategies and eliminate the problems in the case company. By eliminating the conflicting inventory management activities of different departments, inventory management performance for the entire system is improved.     

An institutional theory perspective of business continuity planning for purchasing and supply management

Supply chains are increasingly susceptible to unplanned, unanticipated disruptions. With the implementation of the practices of lean systems, total quality management (TQM), time-based competition and other supply chain improvement initiatives, managers now realize that their supply chains are fragile, particularly to environmental disruptions outside their control. As a result of recent events including 11 September 2001, a system is now emerging in purchasing to manage supply risk characterised as having a very low probability of occurrence, difficult to predict, and with a potentially catastrophic impact on the organization. This paper presents case study research findings examining how and why firms create business continuity plans to manage this risk. Propositions are then presented from an institutional theory perspective to examine how various isomorphic pressures result in firms having similar risk management practices embedded in their supply management practices over time.     

A robust scheduling for the multi-mode project scheduling problem with a given deadline under uncertainty of activity duration

The problem of this paper deals with the multi-mode project scheduling problem under uncertainty of activity duration where only the renewable resources are taken into account and a given deadline has to be met at the cost of recruiting additional resources. A heuristic algorithm is employed to solve this problem, and to maintain the robustness of the baseline schedule, the concept of critical chain project management (CCPM) is applied in which a new definition to resource buffer is considered. A simulation methodology is used to determine the size and location of resource buffers in the schedules in which three different buffer sizes and three different uncertainty levels are considered. Results and analysis of the simulation outcomes illustrate that resource buffers are useful and should be simulated by the CCPM schedules, as they help to decrease the total duration of the project during implementation and meet the deadline of the project with more assurance.     

基于全寿命周期的火电工程建设管理研究

针对火电工程建设具有很强的复杂性和特殊性,将全寿命周期理论应用于火电工程建设的控制和管理领域,建立了集火电工程建设的质量、进度、投资和安全为一体的集成控制概念模型和管理组织模式,论述了火电工程建设过程集成控制流程,并搭建了全寿命周期管理下的火电工程建设信息管理平台。工程应用实例表明,所提出的理论和搭建的平台能有效地提高火电工程建设管理水平,为火电工程建设的控制与管理提供理论与技术支持。     

Postponement in supply chain risk management: a complexity perspective

While the poor response implications of supply are often not elaborated on in the literature, postponement has recently been mentioned as a useful tool for managing supply risk and disruptions. To interpret this in a more complete manner, this paper has attempted to explore the role of postponement in supply chain risk management from a complexity perspective. After a review of the relevant literature, it first draws insights emerging from normal accident theory that addresses the system characteristics of catastrophic accidents and applies them to supply chain disruptions. This is followed by the utilisation of normal accident theory to explain the role of postponement in supply chain risk management. Building on this, this paper also investigates the complexity implications of some commonly recommended measures to mitigate supply chain disruptions. In certain circumstances, the introduction of those measures may add to the complexity of a system and thus become inherently infeasible. The paper concludes with a summary and some suggestions for further research.     

基于可持续发展的高速公路扩建 工程的建设管理

阐述了高速公路扩建工程可持续发展概念的内涵和外延。针对扩建工程的可持续发展战略目标,建立可持续发展的目标体系,将高速公路扩建工程作为项目群系统研究,构建了扩建项目全寿命周期集成化管理系统。围绕集成化管理的三维坐标体系,解释了扩建工程全寿命周期的涵义,分析扩建工程的项目群特征及"扩建—运营—交通管理"一体化组织结构。建立了高速公路扩建工程全寿命周期信息结构矩阵和信息管理系统。采用可持续性晴雨表建立高速公路扩建工程可持续发展的评价模型。总结了基于可持续发展的高速公路扩建工程的建设管理能够为后续工程建设和行业发展提供的启示。     

基于前景理论的项目管理计划行为分析

由于现代项目日益复杂和项目所处环境的日益多变,项目所面临的不确定性和风险都在增加。其中,由于行为不确定性所导致的风险日益引起人们的关注。文章以“前景理论”为依托,对项目决策者在一个单活动项目中的计划行为进行了分析,并建立了决策前景值模型。通过确定项目计划者的主观感知费用函数,定义了决策过程中的参照点,并给出了前景值的计算方法;通过模拟不同的决策环境和决策方案,配合数据仿真,对“期望效用理论”和“前景理论”的决策行为进行了讨论。结果表明,“前景理论”在描述计划行为时能够在一定程度上克服“期望效用理论”的不足,可以较准确地刻画决策者在不确定性条件下的计划行为,为后期进一步深入分析奠定了理论基础。     

基于信息不对称的工程项目主体行为三方博弈分析

在分析项目主体之间博弈关系的基础上,建立了一般项目和政府投资项目行为主体三方之间的行为博弈模型,分析了博弈混合策略纳什均衡解。最后从建立完善的建设管理制度、事先监督机制与事后惩罚机制、激励机制与约束机制等方面提出了规范项目主体行为的具体对策。     

Threshold-based method for elevating the system's constraint under theory of constraints

The principal tenet of theory of constraints (TOC) is that there is at least one constraint in each system that limits the ability of achieving higher levels of performance relative to its goal. Maximum utilisation of the constraint leads to maximum output of the system. However, activation of a non-constraint resource at 100% of its capacity does not increase output. Therefore, some resources are not fully utilised. In this paper, the authors use the left capacity of a non-constraint resource (NC) to elevate the system's constraint. It is assumed that the capacity-constrained resource (CCR) is a continuous time Markov process having a two-dimensional state space. The work in the NC is interruptible, allowing a worker in the NC to switch to CCR. The switch from NC to CCR would occur when the queue of waiting parts in the CCR becomes ‘too long’ and vice versa, when there are few parts in the CCR. Returning to the NC from the CCR may require some ‘re-orientation time’ on the part of the switched worker. The goal is to find the maximum output of CCR subject to the time-average number of workers in the NC must be greater than a pre-specified value.     

基于Project 2003的关键链启发式算法

介绍了关键链项目管理的基本方法;针对资源受限项目调度问题,提出了资源冲突时的资源分配原则;以项目工期最小化为目标,以Proiect 2003为辅助工具,提出了一个确定关键链的启发式算法,即在找出关键路径的基础上,从后往前遍历,对发生资源冲突的活动,依资源分配原则修改紧前关系,然后再确定关键链,进而得到了基于关键链项目管理方法的项目调度算法.对算法进行了验证,结果表明算法是有效的.     

基于关键链方法的多项目管理

传统多项目管理中的主要问题表现在级联效应、多任务工作、行为效应等三个方面。本文提出五步骤法将关键链管理中的关键链调度、同步化、缓冲管理应用于多项目管理，建立了关键链多项目管理方法(CCMPM)，并构建了由三个项目组成的多项目环境实例，以工期为评估标准，利用模拟软件Crystal Ball 2000．5模拟项目实施过程，1000次模拟结果显示，经CCMPM优化前后项目平均完工时间为320天／295天，完工保证率为90％的工期为330天／301天。     

基于混合智能算法的多资源约束项目优化调度

 基于关键链项目管理(critical chain project management,CCPM),利用一种混合智能优化算法求解多资源约束项目调度问题,解决传统调度优化算法的不足,提高这类问题的求解质量.首先利用一类启发式算法识别项目关键链,并设置缓冲区尺寸,以项目总工期和在制品库存为优化目标建立数学模型,设计一种混合智能优化算法求解,并对项目问题库中的j30hrs.sm问题和某生产型项目进行实验分析,得到优化的结果.实验表明,采用混合智能算法求解这类问题能得到明显优于一般调度优化算法的结果.     

接驳缓冲设置中的独立时差策略

加入接驳缓冲后可能导致关键链与非关键链产生资源冲突,非关键链溢出等问题,使得关键链调度计划的制定再次复杂化。为优化接驳缓冲的计算,在根方差法的基础上,运用独立时差这一项目网络提供的隐性安全时间,区分非关键链上的活动;并对非关键链上拥有独立时差的活动,改变Goldratt提出的所有非关键活动最晚执行策略,构建考虑独立时差的接驳缓冲设置方法。通过仿真实验,对采用不同接驳缓冲设置法得到的关键链调度计划进行比较;结果表明,新方法能减少接驳缓冲设置引发的问题,并较好地改善了项目工期,项目执行绩效。     

Maximizing supply chain profits with effective order management: integration of activity-based costing and theory of constraints with mixed-integer modelling

The development of a profitable-to-promise order management model in a make-to-order manufacturing environment is presented. The primary objective is to maximize profitability while ensuring that the firm has adequate resources to satisfy demand. The effectiveness of Activity-Based Costing and Theory of Constraints-based approaches is compared to assess order profitability. This order management model uses a mixed-integer program to consider simultaneously capacity, the relevant costs of supply chain resources and profitability. The results suggest that a close examination of cost structures is necessary for choosing an effective framework for a profitable-to-promise application. In manufacturing environments where direct manufacturing costs constitute a relatively small percentage of the total manufacturing cost, it would be beneficial to consider an Activity-Based Costing approach. On the other hand, in environments where direct costs are large, a Theory of Constraints-based approach would suffice.     

Theory of constraints at UniCo: analysing The Goal as a fictional case study

As a fictional case study, Eliyahu Goldratt's novel about manufacturing, The Goal: A Process of Ongoing Improvement, presents a constraint-focused approach to production management. As a novel, the book does not emphasise the quantitative details of the plant improvements. However, a great amount of information about the plant is spread throughout the book. By collecting and analysing this data, a concrete picture of the plant's capacity and its improvements may be developed, which can greatly help the book's readers understand and evaluate the cumulative impact from the plant's ‘process of ongoing improvement’.     

关键链的随机性及其在建筑工程项目进度中的应用

先采用CPM方法计算出项目的关键线路和工期,但是CPM方法没有考虑各种资源对施工的约束,往往与实际不符,而基于关键链方法,可以获取到工程施工过程中的资源约束下的关键链。实际上,施工过程中需要的各种资源又受到某些外界因素的影响,使得这些工序的完成呈现出一定的概率性。所以,本文将随机过程的思想和方法应用到最优关键链的获取中,最终找出最优的施工线路和施工工期。该方法对后续的工程施工具有重要的指导意义。     

A real option-based supply chain project evaluation and scheduling method

Supply chain departments spend their time managing numerous projects that will improve and maintain their supply chains. Recent literature has most frequently described the content of these projects and their scheduling but neglected to include risk and uncertainty in the expected cost, profits and time durations of these projects. In this article, we have introduced real option valuation (ROV) to supply chain project scheduling as a flexible method to quantify those risks. Our proposed two-step framework links ROV to all relevant constraints of a multi-project set-up by binary fuzzy goal programming. We applied the framework to a real-life case study data of 21 projects that were facing numerous risks and resource constraints. The results show how scheduling performance improved in comparison to methods ignoring risk and uncertainty (e.g. net present value-based scheduling). For validation we conducted hypothesis tests and sensitivity analysis, and provide an in-depth discussion. The findings contribute to research and practice by capturing project-related risks and managerial flexibilities in general and in supply chains in particular.     

An operations management perspective on adopting customer-relations management (CRM) software

Enterprise resource planning (ERP) systems are made up of software that chiefly support individual functional areas (e.g., operations management practices and policies), but seeks to share information to support organisation-wide integration goals. In this paper we examine the influences of operations management (OM) customer focus policies and practices, as well as software vendor capabilities in supporting OM, on ERP reasons for adoption of software and vendor selection of customer relations management (CRM) systems. An empirical study utilising structural equation modeling (SEM) is used to determine if an OM customer focus affects the adoption of CRM. The results show that collaboration between OM and marketing managers in the acquisition of CRM software improves business performance and supports the prior research that advocates the need for closer integration of these two functional areas. The results also show that OM reasons for adoption of CRM can have a moderating effect on business performance as well.     

A co-ordination theory approach to restructuring the supply chain: an empirical study from the focal company perspective

In the wake of the global financial crisis, a growing number of firms have begun to reassess their strategic goals and subsequently restructure their global supply chains. Since supply chain restructuring often leads to dramatic changes in the business paradigm, there is a need to examine whether or not it affects the way that firms co-ordinate their business activities and integrate product innovations across the supply chain. Nevertheless, little has been known about the antecedents of supply chain restructuring and the impact of supply chain restructuring on manufacturing practices. To fill the void in this line of research, we propose co-ordination theory that can explain causal links between supply chain restructuring and key strategic variables essential for the supply chain success from focal company perspectives. These strategic variables may include the extent of co-ordination with suppliers, the degree of information sharing with suppliers, and the level of organisational integration. Our empirical analysis, based on the International Manufacturing Strategy Survey IV, confirms the validity of co-ordination theory in that business initiatives intended for greater co-ordination and information sharing with suppliers turned out to be a major driving force behind supply chain restructuring, which facilitates organisational integration.