双约束下关键链项目网络计划技术研究

基于关键链管理思想——"鼓"资源冲突优先调度的原则,在满足紧前约束关系的基础上,提出用FS表示紧前约束和SS表示资源约束的关键链项目网络表示方法,改进了传统的项目网络CPM/PERT技术仅考虑紧前约束的情况。进一步基于资源自由时差的概念论证了关键活动和关键路径理论上的识别思路。     

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.     

关键链上可被部分替代的受限资源动态调度

关键链上受限资源的优化调度,能有效提高系统运作效率,是关键链项目管理的重要研究方向之一.但现有研究主要针对资源能否更新,较少考虑资源的可替代性.针对此,研究了关键链上可被部分替代的受限资源调度问题,以达到提高资源利用率、降低成本等目的.采用α/β/γ三元组方法,将研究的问题描述为以最小化滞后时间和为目标,具有机器适用限制的并行异速机调度问题,并建立对应的数学模型;运用混合重调度策略和改进粒子群算法进行了算法设计;设计了仿真算例,并通过算法比较表明该方法在求解结果和问题求解规模上显著优于传统PSO、GA算法.     

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。     

基于关键链的项目风险管理

关键链项目管理方法是约束理论在项目管理上的应用,是近年来项目管理领域的重要创新。与传统的项目管理方法相比,该方法强调在制定项目计划时考虑现实存在的资源约束,在项目执行过程中的动态管理,以及整个项目管理流程的持续改进。文中讨论基于关键链的软件项目管理方法。基于软件过程工作分解结构,预测各项工作在理想工作条件下的工期,考虑人力资源的约束与冲突,建立项目的关键链。通过对各项工作的风险分析,为关键链、非关键链分别设置项目缓冲、输入缓冲,通过对缓冲区的监控来进行风险的控制和管理。     

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。     

多项目关键链进度优化算法分析

针对多项目进度优化问题,综合应用关键链和社会认知优化算法,保证了多项目计划在不确定环境下的稳定运行。文章首先在保证进度工期最短的前提下,进行了多项目的排序,进而确定对后续项目的影响。通过实例应用于多项目进度管理中,为工程决策与管理者全面而准确地进行多项目管理、掌握项目进度、保证项目如期完工,以及对后续项目进行合理地预测提供了依据。并讨论了应用关键链方法进一步研究的方向。     

基于灰色关键链的项目进度管理方法及应用

针对项目或者任务完成时间具有外延确定而内涵不确定的特点,应用灰色系统思想提出了基于灰色关键链的项目进度管理方法.设计的灰色关键链方法通过改进关键链中缓冲时间的取法,以设置合理的输送缓冲时间(Feeding Buffer)及项目缓冲时间(Project Buffer).最后,通过实例给出了该方法的应用步骤,并将计划评审技术、关键链与灰色关键链进行了比较.     

Research on resource allocation of virtual cluster based on QoS

为了有效实现基于虚拟机技术的高性能计算环境资源调度与分配,以满足用户不同服务质量请求,提出了一种动态可调节的资源分配策略.该策略以用户任务被放缓程度为核心指标,并允许用户根据该指标提出相应的服务质量约束,从资源提供者的角度保证了用户获得相关服务的开销最低,同时总的资源收益最大.对该分配模式下的静态资源分配问题进行了形式化的描述,并结合该策略提出混合背包算法.实验结果表明:面对大规模应用时,该算法较其它一般性算法更易得到效能较优的资源分配方案.     

考虑技能因素的软件项目关键链缓冲区大小计算方法

关键链项目管理方法是提高项目进度计划有效性、降低进度风险的重要手段。目前,软件项目中关键链缓冲区大小设置的研究仍处在起步阶段。鉴于此,以软件开发项目为研究对象,针对软件开发项目的不确定性和智力密集特性,用随机变量对不确定的任务工作量建模,并将员工的多任务特性和超负荷工作特性量化为分散系数和超负荷工作系数,进而提出了一种更适合软件项目的关键链缓冲区大小计算方法。基于软件项目的案例对所提方法进行了验证。此外,仿真对比实验的结果表明,以缓冲区总大小、项目缓冲平均消耗比例、项目进度风险、预测误差四种指标为性能评价标准,所提方法整体优于经典的剪切粘贴法和根方差法。     

Quantification of Project Execution Complexity and its Effect on Performance of Infrastructure Development Projects

Growing complexity is one of the main reasons behind the failure of many projects. Thus, identifying and measuring complexity is crucial to the success of any project. Various schedule complexity indices have been proposed in the past, but a comprehensive complexity measurement tool encompassing factors of schedule along with other important project constraints, such as time and scope, is still missing. First, a theoretical framework consisting of 46 complexity factors has been developed through literature review followed by its refinement through a three-round Delphi study. The complexity factors are categorized into three categories, namely, Schedule complexity, Scope complexity and Cost/Resource complexity. The Project Execution Complexity Index (PECI) tool is proposed, followed by development of a questionnaire in order to compute PECI values and validated using three infrastructure development projects during the planning phase. Finally, in the execution phase, the performance of the projects is measured through earned value analysis. PECI values are then mapped with project performance indices (i.e., schedule/cost performance index) in order to assess the effect of project complexity on the performance of projects. The results showed that projects with higher complexity tend to have larger cost or schedule overruns. These case projects are also ranked according to the degree of their complexity on the complexity scale. This ranking can help decision makers to decide which projects should be included in the portfolio and which projects need prioritizing through assigning resources more efficiently. The proposed PECI tool may also help project managers to better anticipate prospective difficulties during the initial stages of the project lifecycle.     

Scheduling Multi-Mode Resource-Constrained Projects Using Heuristic Rules Under Uncertainty Environment

Project scheduling is a key objective of many models and is the proposed method for project planning and management. Project scheduling problems depend on precedence relationships and resource constraints, in addition to some other limitations for achieving a subset of goals. Project scheduling problems are dependent on many limitations, including limitations of precedence relationships, resource constraints, and some other limitations for achieving a subset of goals. Deterministic project scheduling models consider all information about the scheduling problem such as activity durations and precedence relationships information resources available and required, which are known and stable during the implementation process. The concept of deterministic project scheduling conflicts with real situations, in which in many cases, some data on the activity' s durations of the project and the degree of availability of resources change or may have different modes and strategies during the process of project implementation for dealing with multi-mode conditions surrounded by projects and their activity durations. Scheduling the multi-mode resource-constrained project problem is an optimization problem whose minimum project duration subject to the availability of resources is of particular interest to us. We use the multi-mode resource allocation and scheduling model that takes into account the dynamicity features of all parameters, that is, the scheduling process must be flexible to dynamic environment features. In this paper, we propose five priority heuristic rules for scheduling multi-mode resource-constrained projects under dynamicity features for more realistic situations, in which we apply the proposed heuristic rules (PHR) for scheduling multi-mode resource-constrained projects. Five projects are considered test problems for the PHR. The obtained results rendered by these priority rules for the test problems are compared by the results obtained from 10 well-known heuristics rules rendered for the same test problems. The results in many cases of the proposed priority rules are very promising, where they achieve better scheduling dates in many test case problems and the same results for the others. The proposed model is based on the dynamic features for project topography.     

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。     

Robustness to Variability in Project Networks

Our aim in this paper is to highlight the relative impact of activity variability on the completion time of different project configurations. We show that there is, in general no categorical connection between the stage of a project in its life-cycle and the impact of increased activity variability on the expected remaining project duration. Thus investing resources to decrease activity variability is, in general, as important in the early stages of the project life-cycle as it is in the later stages. However, our analysis suggests that in projects with dominant critical paths, it pays to invest resources to reduce activity variability at an early stage rather than at a later stage in the project. We apply some of our analytical results to gain insights into the issue of structuring project activities into work packets and assigning the work packets to project teams. We extend our framework to examine different modes of subcontracting projects.     

Re-planning support system for make-to-order production with reserved resources

Make-to-order production is often organized into projects with their own objectives. Such projects use strategic and critical resources that must be reserved at a strategic or a tactical planning level. When external resources need to be taken into consideration, they must be reserved based on their set of free time windows. A medium-term planning support system for the manager of a project where external resources are critical is proposed. By providing explanations for project inconsistencies, this system enables the decision-maker to restore consistency. After creating the initial medium-term plan, planning activity essentially consists in updating the existing schedule of a project when unexpected events arise. These may be due to internal or external disturbances. Indicators are proposed to help the manager follow the dynamic impact the disturbances will have on the project.     

基于均衡优化的项目多技能人力资源指派与调度方法

为提高项目人力资源使用效率,提出一种项目多技能人力资源调度与指派优化方法。首先,采用启发式方法对项目进行资源均衡优化,降低人力资源需求高峰用量;然后,识别调度方案中活动间的重叠关系并将其转化为人员指派优化问题的有效约束;最后,建立整数规划模型并通过编程计算。研究结果表明,使用该方法可快速地找到问题的近优解,用较少的人力资源完成项目任务,从而有效地降低项目人力资源成本。     

属性相关的关键链计划缓冲设置方法

考虑链中包含的工序数大小、工序执行时间不确定程度和开工柔性程度三个与具体项目相关的属性,研究关键链项目计划缓冲设置.以项目计划周期和完工保证率为评价目标,通过仿真实验方法评价属性对项目计划的影响.根据仿真实验结果分析.提出缓冲设置的改进方法.算例表明与切粘法和根方差法相比改进方法可显著改善项目计划性能.     

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.     

Two Way Integration of Engineering Education through a Design Project

Horizontal and vertical integration of engineering education is achieved through an early‐design project where students get acquainted with Total Quality Management (TQM) principles and design processes from year‐one of their University education. The project is embedded in the undergraduate chemical engineering curriculum as an activity that involves horizontally several first‐year subjects and vertically a fourth‐year Project Management Practice course and a related Project Management subject. An assessment of the integrated design project indicates that effective teaching and learning spreads through the curriculum, with fourth‐year students acting as project managers and experiencing engineering practice. These management and leadership training processes include a shared responsibility in the organization and in the development of the project, which are key factors for the success of the integrated activity. They are also a first step towards the ETSEQ goal of becoming a sustainable student‐centered educational system.