An Improved Formulation for the Job-Shop Scheduling Problem

This paper presents an extension of an earlier integer programming model developed by other authors to formulate a general n-job, m-machine job-shop problem. The new formulation involves substantially fewer functional constraints at the expense of an increase in the number of upper bound variables. This reduction of functional constraints, together with the imposition of upper and lower bounds on the objective value, significantly reduces the computation time for solving the integer model for the job-shop scheduling problem.     

An Improved,Multiplier Adjustment Procedure for the Segregated Storage Problem

The segregated storage problem consists of determining an optimal distribution of products among existing storage compartments such that at most one product may be stored in a given compartment. The problem is solved using linear programming, Lagrangean relaxation and multiplier adjustment techniques. The procedures are easily adapted to obtain good heuristic solutions quickly. Computational results are given.     

一种改进的多模式项目反应性调度问题

既有的项目反应性调度问题只关注了基准调度方案的稳定性,而忽略了项目调度目标的最优实现。本文提出了一种两阶段多模式资源受限项目反应性调度问题。第一阶段,在新的项目执行环境下,对项目进行完全重调度,得到新的最优调度目标值。第二阶段,以新的最优调度目标值为约束,以最大化调度稳定性为目标,求得新的最优调度方案。针对问题特点,基于IBM ILOG优化编程语言OPL和CPLEX V12.8.0,设计出该问题的求解程序。最后,基于标准算例,对本文提出的反应性调度方法、既有的反应性调度方法、完全重调度方法进行了充分的比较测试,结果表明本文提出的反应性调度方法在缩短项目工期、保护基准方案的稳定性方面具有明显优势。     

求解零等待流水车间调度问题的改进蝙蝠算法

针对零等待流水车间调度问题特性,设计了一种蝙蝠算法进行求解.算法模拟蝙蝠捕食搜索行为进行寻优,利用基于最小位置值规则的随机键编码方式来表示问题解,采用基于NEH方法的局部搜索策略和随机交换、插入、逆序操作的变邻域搜索策略来提高局部优化性能,进一步根据Metropolis概率准则接受劣解来避免早熟.通过典型算例对所提算法进行仿真测试并与粒子群算法和RAJ启发式算法进行对比,结果表明所设计算法求解零等待流水车间调度问题的有效性和优越性,是求解流水车间生产调度问题的一种有效工具.     

占线订单排序C——收益函数下改进的随机策略

对于订单具有紧交货期限且以最大化完工总收益为目标的占线订单排序问题，Woeginger（1994）提出了完工收益与订单长度满足C——收益函数关系的一类模型，并给出了竞争比为4的最优确定性策略。本文针对该模型设计了一个简单的随机策略，并证明其具有竞争比2。该策略明显简单于已有的各种随机策略；同时，本文结论大大改进了Seiden（1998）所给出的当前最好竞争比3．732。     

求解集束型装备调度问题的改进遗传算法

针对半导体制造中的有滞留时间约束集束型装备调度问题,以最小化生产周期为目标,建立问题的数学模型,提出基于机械手搬运作业顺序编码的改进遗传算法.设计基于禁止区间法的启发式构造算法以生成初始种群,避免了不可行染色体的产生;通过互换染色体中处于机械手全等待的基因位置,以及基于图论的不可行解修复技术改进局部搜索效率,避免冗余迭代和陷入局部最优等现象.与遗传算法、混合量子进化算法的仿真实验比较,验证了提出算法的有效性和鲁棒性.     

基于占线排序 D-收益函数的战时维修改进策略

由于战时作战强度、战场环境变化不确定性,导致战损或故障装备的产生无法提前获知,从而战时装备维修机构受领维修任务进行装备维修作业成为一个占线问题。采用占线单服务排序理论对该问题进行建模,定义了战时装备维修收益函数,设计了一种改进的基于单位平均收益的单服务维修策略,推断了其有效竞争在概率意义上为2／η（η＞＞1,η是与不同维修任务类型发生概率相关的统计量）,为战时装备维修策略选择提供了新思路和可行做法。     

改进的布谷鸟算法求解考虑运输时间的分布式柔性流水车间调度问题

针对分布式制造环境下多车间调度问题特点,结合企业实际生产情况,考虑相邻工序间的运输时间,建立以最小化最大完工时间为优化目标的分布式柔性流水车间调度模型,提出一种改进布谷鸟算法用于求解该模型。算法改进包括设计了一种基于工序、车间和机器的三层编码方案;根据问题特点设计了混合种群初始化策略以提高种群质量;改进了布谷鸟搜索操作使其适用于求解该模型;设计了一种种群进化策略以提高算法收敛速度及解的质量。最后通过仿真实验,与多种算法对比,验证所提算法的有效性和优越性。     

改进二元分布估计算法求解置换流水车间调度问题

针对置换流水车间调度这类组合最优化问题的求解,提出了一种改进二元分布估计算法(Improved binary estimation distribution algorithm, I-EDA)。算法以二元分布估计算法为架构,使用NEH(Nawaz-Enscore-Ham)启发式算法生成初始解,提高了初始解的质量;通过对优势解的统计采样构建位置矩阵模型和链接矩阵模型,依照两个矩阵模型的合并概率组合链接区块产生子代。提出了NEH插入式重组策略和基于位置概率的交换策略和两种全新局部搜索机制替代原二元分布估计算法的相邻交换法,以进一步筛选优势解。最后通过对Reeves标准测试集的仿真实验和算法比较验证了所提出算法的有效性。     

经济批量排产问题的改进算法:设定最高允许高度

经济批量排产问题是指在生产准备费用与库存费用最低的情况下,协调地、周期性地生产多种产品的问题.由于此问题是NP-hard的,人们一种致力于寻找快速地求解高质量的近似最优解的方法.在将生产次数舍入为2的幂次后,误差小,获得可行解的速度快.研究的经济批量排产问题考虑了产品货架存放期因素.指出了Dobson算法的不足,并提出了基于2的幂次条件的改进算法.改进算法设定了最高允许高度,首先给部分箱进行装箱.由于能获得高质量的生产排产,因此,算法能获得2的幂次条件下的高质量解.给出一个算例,计算结果显示,算法结果更优.     

A Solution Procedure for the Vehicle-Scheduling Problem Based on Iterative Route Improvement

A solution routine, based on iterative improvement of an initial solution, has been developed for vehicle-scheduling problems. The improving routine combines a number of very simple procedures, each of which tries to reduce the overall distance travelled by moving customers in a systematic way. Tests were run using standard problems, and results obtained were of good quality. An application of the procedure is described briefly.     

The Solution of a Railway Locomotive Scheduling Problem

A method is described for finding a minimum cost set of schedules for railway locomotives to work a given set of trains. The times at which the trains start may be fixed or variable. A heuristic method, based on a linear programming model, is described. This gives good integer solutions to the problem.     

An Improved Heuristic for the Quadratic Assignment Problem

A technique is described whereby the computational efficiency of the Lashkari-Jaisingh heuristic for the quadratic assignment problem is greatly enhanced. Results for the modified heuristic are presented which demonstrate that it provides solutions of consistently high quality at relatively small computational cost.     

An Improved Algorithm for the Non-Guillotine-Constrained Cutting-Stock Problem

A personal-computer-based algorithm to solve the non-guillotine-constrained two-dimensional cutting-stock problem is developed. The problem is constrained to single-sized rectangles placed orthogonally on a larger containing rectangle. The algorithm uses the linear combination of box lengths and widths that minimizes waste along the cutting stock's length and width to determine an optimal layout. The algorithm's performance is evaluated using two sets of test cases and compared to the results of other algorithms.     

An Improved Algorithm for the Multi-commodity Location Problem

Distribution systems designs commonly require the optimal location decisions of regional ware-houses or distribution centers which function as intermediate facilities between plants and customers. This paper deals with such a location problem in which the facilities can handle one of several commodities. We term this problem the multi-commodity facility location problem. A branch and bound algorithm is proposed for solving this problem. Improved bounds are developed for increasing the efficiency of the algorithm. Computational results are provided.     

改进的混合算法求解车间作业调度问题

车间作业调度问题是个典型的NP-hard问题,为了更有效的解决车间作业调度问题,提出了一种改进的混合算法(IGASA).算法设计了一种基于当前最优解的免疫算子,算子对当前最优个体中选取运行时间最少的一台机器上的工件顺序当作疫苗,并用车间调度问题的图论模型解释了此算子的合理性.最后通过大量实验证明改进的混合算法的性能的优越性,从而证明设计的免疫算子是有意义的.     

工序顺序柔性的作业车间调度问题的改进遗传算法求解

针对在工艺设计中提供工序顺序柔性的作业车间调度问题,总结了该问题中柔性工序顺序的类型和特点,并提出了一种求解该问题的改进遗传算法.以尽可能缩短制造周期为目标,结合问题特点,改进了染色体的编码方式,在常用的基于工序顺序的编码方法上融入了基于柔性工序顺序的编码方法,并据此设计了相应的交叉、变异等操作,防止遗传过程中不可行解的产生,避免染色体修复,提高求解效率.最后以MATLAB为工具用某轴承公司的实际生产数据对该算法进行了仿真.通过与不考虑工序顺序柔性的作业车间调度问题遗传算法求解结果进行对比,证明了该算法可行性和有效性.     

A Primal Simplex Based Solution Procedure for the Rectilinear Distance Multifacility Location Problem

In this paper a primal simplex based solution procedure is developed for a multiproduct, multi-facility location problem using rectilinear distance measures. By overcoming the combinatorial nature of the problem which arises in the presence of degeneracy, this procedure is capable of handling large size problems. Computational results are also provided.     

A “Branch-and-Bound” Algorithm for the Exact Solution of the Three-Machine Scheduling Problem

By combining Roy's graph-theoretical interpretation of the problem of job scheduling on machines and some general results of his theory with the “branch-and-bound” method recently applied by Little et al. to the travelling salesman problem an algorithm has been obtained for the exact solution of the scheduling problem in the case of three machines. The working of the algorithm has been illustrated by numerical examples and possibilities of further investigations have been indicated.