资源约束项目排序问题的一种修正蚁群算法

根据蚁群算法的性质与资源约束项目排序问题(CPSP:Resource-Constrained Project Schedul- ing Problem)的特征,本文给出了蚁群算法中信息素的表示及更新方案、启发信息的计算方法等,由此提出了一种求解RCPSP的修正蚁群算法。最后,通过对项目排序问题库中的标准问题集进行计算,结果表明本文提出的修正蚁群算法是可行优良的。     

多资源约束批量计划问题的分散搜索算法

为求解多资源有资源约束的生产批量计划问题,提出了一种基于分散搜索算法(Scatter Search,SS)和能力调整方法(Capacity Adjusting Methods,CAM)相结合的方法,阐明了该方法的具体实现过程。在对不可行解进行资源能力调整的实施阶段,采用先顺序-再逆序的方式进行处理。通过对文献中的仿真算例进行计算和结果比较,表明了该算法在寻优能力、求解速度和稳定性方面的优势。     

Resource Allocation of a Multi-Resource Project for Variable Resource Availabilities

An algorithm for resource allocation of multi-resource projects is described for the assumption of unlimited resource availabilities. The basis of the allocation is a binary enumeration of all feasible activity combinations, from which the daily optimum is obtained. Optimality is defined by the minimal 'schedule deviation,' which measures the weighted deviation squares between future resource loads and currently assigned resource levels. The algorithm simplifies both scheduling and project control, since the next periods schedule depends only on the current schedule status. Appropriate changes in levels for all resources over the project duration are consistent with the needs of project managers in practice.     

基于混沌差分进化粒子群算法的模糊资源受限项目调度问题

本文研究了工期模糊情况下的资源受限项目调度问题,采用一种基于区间数距离的模糊取最大运算比较模糊工期的大小,解决了以往研究中忽略的工期模糊情况下,项目关键路径可能会发生改变,相应地各活动的模糊调度时间以及项目的模糊最短工期也可能随之发生改变的问题。引入一种基于混沌和差分进化的混合粒子群优化算法,并对算法的惯性权重进行改进来求解上述问题。通过一个算例验证了所建立模型及提出方法的有效性。     

A Simple Algorithm for A Workforce Scheduling Model

This paper presents a simple solution algorithm to the problem of scheduling workforce for an organization operated seven days a week. For a given number of full-time workers, the objective is to maximize the total number of workers who get two consecutive days off. It can be shown that due to the special structure of the derived mathematical model, an optimal schedule may be found by a few arithmetic steps without the computer assistance which other existing methods require.     

A Branch-and-Bound Algorithm for Flow Shop Scheduling Problems

This article is concerned with the solution of the flow shop scheduling problem in which all jobs have the same machine ordering. A branch-and-bound algorithm is developed for finding the sequence of J jobs to be processed on M machines which minimizes the schedule time. Thib algorithm consists of branching and bounding processes, but without the backtracking process which guarantees optimality. The procedure employed is that in constructing a subset of feasible sequences, a node representing a partial sequence is branched. Selection of the node depends on the lower-bound concept as a decision rule. This lower bound is based on resolving the conflict of jobs on the last machine. By using this algorithm, the number of explored nodes is considerably reduced and, hence, the computational effort involved in obtaining an optimal or near-optimal solution is decreased. High quality of solutions is obtained. Computationally, this algorithm extends the size of problems that can reasonably be solved.     

针对项目式生产调度的模拟退火算法

分析了某航空航天企业生产现状,考虑到工时不确定性,建立了数学模型。提出了模拟退火启发式算法,以此制定主动调度计划,并且结合企业生产的实际情况,进行了验证。应用实践表明,相较于单纯求解工期最短的调度计划,该算法的解能很大程度上提高计划的鲁棒性,不需要过多延长工期,对于工时可变范围大的生产项目尤其适用。     

钢管冷区生产调度的一种启发式算法

基于国内大型钢铁公司的实际操作,运用离散化时间的方法把钢管冷区生产调度抽象为可中断Job-Shop问题.同时考虑前置库存限制、生产尽可能连续、部分人工调度等约束条件,以最小化中断次数和尽可能满足人工调度为目标,建立相应的数学模型.再依据约束条件的主次性设计生产调度规则(赋值规则和生产规则),根据实际生产流程设计启发式算法.运用该算法对该问题的大规模算例进行求解,其结果在满足了约束条件情况下达到比较理想的中断次数.     

A Scheduling Algorithm for the Unbalanced Production Line

This paper presents procedures for obtaining feasible fractional and integer assignments which can be used to schedule manpower for the unbalanced production line. The objective is to minimize the cost of the total in-process inventory. A mathematical model is formulated and then used to calculate fractional assignments using linear programming and integer assignments using integer programming. An algorithm is then developed which provides the equivalent fractional solution as obtained from linear programming followed by a heuristic algorithm which converts these fractional assignments to feasible integer assignments. Sample problems and their solutions are provided to illustrate the assignment procedures.     

遗传算法在项目进度计划中的应用

在项目进度计划中,将工序的前后约束关系变换成一个关联矩阵,从可执行的工序集合中随机产生初始化种群,采用改进型的双点交叉算子,并提出了基于关系矩阵的邻位变异算子,避免了不可行个体的产生。文章给出一个3种资源约束的多项目进度计划实例以说明该算法的有效性。     

面向柔性作业调度问题的启发性规则改进遗传算法

对柔性作业调度问题,提出了一种启发性规则的改进遗传求解方法,此方法从启发性规则出发产生初始调度解。通过对初始调度解进行比较而产生初始种群。对初始种群通过启发规则的改进遗传算法进行优化计算,对染色体进行交叉、变异、交换和选择操作,应用启发式规则搜索关键工序并提高关键工序的交换、变异操作概率,在变异操作中利用启发式规则对变异过程加以引导,从而得到优化解。将此方法运用于一系列典型柔性调度问题进行了实验求解,并将求解结果与其他的计算方法进行了比较,表明此方法能提高求解效率,适合复杂的柔性作业调度问题求解。     

混合流程型企业主生产计划的启发式算法

提出了一个新的启发式算法,该启发式算法称为多目标主生产计划算法(MOMPS),用于解决混合流水线车间的主生产计划安排,该启发式算法主要有以下目标:最小化拖期惩罚,最小化完工时间,最小化装设和库存成本等.该算法先对所有的定单进行排序,然后根据最小生产成本树及其该树的最大生产能力进行定单的分配,如果定单数量超出了最大生产能力,对生产网络进行调整,通过比较次优生产成本树和拖期以后的最小生产成本决定定单是否该拖期.最后通过和一般的线性规划进行比较,得出该算法在解决混合流程型企业的多目标主生产计划的制定中十分有效,有时得到的结果和线性规划模型解出的解是一致的.     

A Grafted Genetic Algorithm for the Job-Shop Scheduling Problem

The standard genetic algorithm has limitations of a low convergence rate and premature convergence in solving the job-shop scheduling problem. To overcome these limitations, this paper presents a new improved hybrid genetic algorithm on the basis of the idea of graft in botany. Through the introduction of a grafted population and crossover probability matrix, this algorithm accelerates the convergence rate greatly and also increases the ability to fight premature convergence. Finally, the approach is tested on a set of standard instances taken from the literature and compared with other approaches. The computation results validate the effectiveness of the proposed algorithm.     

考虑急件到达的单机鲁棒调度方法

实际生产过程中经常会有急件到达。由于急件的优先级最高,其到达容易扰乱初始调度,使实际调度性能恶化,影响调度目标的实现。针对以总拖期为目标且带有释放时间的单机调度问题,研究了在有急件到达情况下的鲁棒调度方法,以降低急件对实际调度性能的影响。鉴于该调度问题是NP hard问题,根据工件释放时间和交货期的关系构造“金字塔”结构,获得该调度问题的占优性质。根据这些占优性质和急件到达特点,研究急件到达情景下的占优规则,据此求解急件到达情景下的占优调度集合,作为鲁棒调度的备选调度方案集合。提出了应对急件到达的鲁棒调度算法。给出仿真算例验证了算法的有效性,算例表明本文给出的鲁棒调度方法能有效避免急件到达造成实际调度性能的恶化。      

A Branch-and-Bound Algorithm for the Continuous-Process Job-Shop Scheduling Problem

The continuous-process job-shop scheduling problem (CPJS) arises typically in the following way: (1) a set of M machines or production facilities are available; (2) a set of N jobs are to be processed through these machines in accordance with a technological matrix; (3) the machines associated with a given job must all be used simultaneously for the completion of this job; (4) a predetermined production time is required for each job; (5) the objective is to determine a production schedule which minimizes the total completion time (makespan) of all jobs. A branch-and-bound type algorithm for the solution of the (CPJS) problem is presented.     

Optimal Project Scheduling with Materials Ordering

A mixed integer 0-1 programming formulation of a Project Scheduling-Materials Ordering Problem (PSMOP) is presented that provides an optimal schedule of project activities and materials orders. It is proven that an optimal solution may be found by decomposing the problem into the derivation of the project schedule and the subsequent derivation of materials lot sizes.     

基于结构矩阵的项目进度周期的计算方法

针对项目进度周期中作业间的交叠关系,引入时间因子概念,设立了信息流与紧前紧后时间因子间的关系,用依赖结构矩阵(DSM)方法,建立项目进度周期计算模型,经实例比较,用该模型计算的进度周期与PERT方法计算的结果相比缩短了约1/3.     

基于聚类的粒子群优化算法在MES调度中的应用

针对传统调度算法寻优效率低的弱点,从MES功能出发,将其调度功能单独抽出,提出了基于聚类的粒子群优化算法,将聚类用于粒子群搜索空间的改进。仿真结果表明了该算法的有效性。     

一种分布式联合输入输出排队结构及其调度算法

分析论证了分布式联合输入输出排队(DCIOQ)结构模拟输出排队调度的充分条件,提出了一类满足这一条件的调度算法,并从工程实现的角度给出了这类算法的一种简易实现方案。与传统方案相比,该方案不仅具有高的带宽利用效率和良好的调度公平性,而且工程实现复杂度较低。     

一类多资源调度问题的优化算法

若调度系统中的作业或任务需要一个或多个资源共同完成， 则这一类调度问题被称为多资源（或多处理机）调度问题。本文针对Jobshop中的这一调度问题，提出了基于遗传的优化调度算法，并用实例证实了该算法的有效性。