用正弦函数描述非线性惯性权重的微粒群算法

为改进标准微粒子群算法,提出了一种用Sin函数非线性描述惯性权重动态调整微粒群的方法。由于原算法存在早熟收敛和搜索效率低,提出改进基本微粒群算法的惯性权重参数,将微粒群算法中的惯性权重用正弦函数来描述,通过对粒子位置和速度进行自适应非线性调整,使算法在前期阶段具有较快的收敛速度,在算法后期局部搜索能力也不错,减少了微粒陷入局部极值的机会,使结果收敛于全局最优解,为了验证算法的有效性,采用Shaffer’s F6和Levy No.5函数进行测试,实验结果表明,新方法具有比较好的效果。     

基于混沌序列的自适应粒子群优化算法

提出一种改进粒子群局部搜索能力的自适应优化算法。通过大量仿真试验,考察粒子平均速度和收敛性之间的关系,给出一种新的自适应调整权重策略。以粒子平均速度作为反馈信息,动态调整权重因子,控制粒子速度并使其沿理想速度曲线下降。在搜索过程中引入混沌序列以改进算法的局部搜索能力。对经典函数的测试结果表明,改进的混合算法通过微粒自适应更新机制确保了全局搜索性能和局部搜索性能的动态平衡,在稳定性和精度上均优于普通PSO算法。     

多阶段多模型的改进微粒群优化算法

针对微粒群优化算法在解决复杂优化问题时易于出现早熟收敛现象,提出了一种多阶段多模型的改进微粒群优化算法。考虑寻优不同阶段的开发与探测能力需求的差异,算法将寻优过程分成3个阶段,各阶段采用不同的模型进行进化。第一阶段利用标准微粒群优化算法发现局部极值的邻域;第二阶段利用Cognition Only模型快速找到局部极值点,提高寻优效率;第三阶段,提出了一种改进的进化模型,利于粒子快速跳出局部极值点,寻找到全局最优点。4种复杂测试函数的实验结果表明：该算法比标准微粒群优化算法（PSO）和基于不同进化模型的两群优化算法（TSE-PSO）更容易找到全局最优解,相比两群微粒群优化算法,还能在一定程度上提高优化效率。     

改进微粒群算法在机器人路径规划中的应用

研究机器人路径规划问题,是为了设定合理最短路径、最快速度、小能耗的优化路径.由于目前微粒群算法应用在路径规划中易陷入局部最优、搜索时间长等缺点,在微粒群算法基础上,提出一种引入了交叉算子和变异算子的改进算法进行路径规划设计,并采用栅格法对机器人实际运动环境进行三维空间建模.在微粒群算法中引入交叉算子,使成对的粒子可以进行信息交换,以便粒子具有了向新的搜索空间飞行的能力;同时引入变异算子,使其坐标值被随机更新,增强了微粒群算法跳出局部最优点的能力.仿真结果表明改进算法简单有效,收敛速度快且具有优秀的搜索能力,为优化机器人路径规划性能提供了依据.     

一种基于栅格的动态粒子数微粒群算法

微粒群算法的全局搜索性能容易受到局部极值点的影响.对此,提出一种基于栅格的动态粒子数微粒群算法(GB-DPPPSO).通过设计栅格信息更新策略,粒子产生策略和粒子消灭策略,可以根据种群搜索情况动态控制粒子数变化,以保持种群多样性,提高全局搜索性能.通过对4个典型数学验证函数的仿真实验,表明了该算法相对于DPPPSO在全局搜索成功率和搜索效率两方面均有明显改进.

     

基于混沌序列的粒子群优化算法

提出一种改进粒子群局部搜索能力的优化算法,对于陷入局部极小点的情性粒子,引入混沌序列重新初始化,在迭代中产生局部最优解的邻域点,帮助情性粒子逃商束缚并快速搜寻到最优解．对经典函数的测试计算表明。改进的混合算法通过微粒自适应更新机制确保了全局搜索性能和局部搜索性能的动态平衡,而且保持了PSO计算简洁的特点,在收敛速度和精度上均优于普通的PSO算法.     

一种基于栅格的动态粒子数微粒群算法

微粒群算法的全局搜索性能容易受到局部极值点的影响,对此,提出一种基于栅格的动态粒子数微粒群算法(GB-DPPPSO).通过设计栅格信息更新策略、粒子产生策略和粒子消灭策略,可以根据种群搜索情况动态控制粒子数变化,以保持种群多样性,提高全局搜索性能,通过对4个典型数学验证函数的仿真实验,表明了该算法相对于DPPPSO)在全局搜索成功率和搜索效率两方面均有明显改进.     

基于种群规模动态减小的混合微粒群优化算法研究

针对基本微粒群优化(PSO,particle swarm optimization)算法存在早熟、易陷入局部极值等缺点,提出了一种改进的PSO优化算法。该算法分为全局搜索和局部搜索两个阶段。在全局搜索阶段采用基本PSO算法快速收缩搜索范围;在局部搜索阶段将PSO算法与模拟退火(SA,simulated annealing)算法结合,通过产生部分变异微粒确保算法能够跳出局部极值。同时为提高搜索效率,动态地减少种群规模。仿真结果表明,该算法具有较好的优化性能以及较高的执行效率。     

求解车间调度问题的2阶段混合粒子群优化算法

针对车间调度问题,提出了一种2阶段混合粒了群算法(TS-HPSO).该算法在第1阶段为每个粒子设置较大的惯性系数w,同时去掉了粒子的社会学习能力,从而保证每个微粒在局部范围内充分搜索.第2阶段的混合粒子群算法以第1阶段每个粒子找到的最好解作为初始解,同时以遗传算法中的变异操作保证粒了多样性;为保证算法的寻优能力,对全局gbest进行贪婪邻域搜索.计算结果证明了本算法的有效性.     

一种改进的微粒群算法*

通过在微粒群算法中引入排雷策略的思想,对微粒群优化算法进行改进,使微粒群算法能摆脱局部极值点的束缚;另外通过在算法的迭代过程中加入旋转方向法,加快算法的收敛速度,从而形成一种新的改进粒子群算法。通过对三个典型函数进行优化计算,并与其他文献的改进微粒群算法的优化结果进行比较,表明基于排雷策略的改进算法很好地解决了粒子群优化算法早收敛、难以跳出局部极值点和收敛较慢的问题。     

A generalized constructive algorithm using insertion-based heuristics

In this paper, a generalized constructive algorithm referred to as GCA is presented which makes it possible to select a wide variety of heuristics just by the selection of its arguments values. A general framework for generating permutations of integers is presented. This framework, referred to as PERMGEN, forms a link between the numbering of permutations and steps in the insertion-based heuristics. A number of arguments controlling the operation of GCA are identified. Features and benefits of the generalized algorithm are presented through the extension of the NEH heuristic, a successful heuristic solution approach of Nawaz, Enscore, and Ham for the permutation flowshop problem (PFSP). The goal of the experimental study is to improve the performance of the NEH heuristic on the PFSP. To achieve this goal, the space of algorithmic control arguments is searched for a combination of values that define an algorithm providing lower makespan solutions than NEH, in a linear increase of CPU time. Computational experiments on a set of 120 benchmark problem instances, originally proposed by Taillard, are performed to establish a more robust version of the original NEH constructive heuristic. The proposed procedures outperform NEH, preserving its efficiency and simplicity.     

一种求解无等待流水车间调度优化的启发式算法

提出了一种新的启发式算法,用于求解无等待流水车间调度问题的总流水时间指标。该算法命名为标准差启发,基于著名的NEH启发算法。首先阐述了总流水时间指标;其次描述了标准差启发算法的过程;最后用标准差启发算法求解标准实验案例,通过实验并与其他启发式算法比较,验证了标准差启发算法在求解无等待流水车间调度问题总流水时间指标的有效性。     

基于总加权完成时间的可重入混合流水车间调度问题

研究以最小化总加权完成时间为目标的可重入混合流水车间调度问题(RHFS-TWC),并构建问题的整数规划模型.根据模型的特点,设计基于二维矩阵组的调度解编码方案,结合NEH启发式算法确定工件初始加工顺序,生成高质量初始调度解群.为避免算法陷入早熟及扩大解的搜索空间,给出IGA的遗传参数自适应调整策略,最终形成NEH-IGA融合求解策略.针对不同规模问题分别用传统GA、基于遗传参数自适应调整的IGA、NEH启发式、NEH-IGA算法进行仿真测试,仿真结果表明NEH启发式和遗传参数自适应动态调整策略的引入有效改善了原有GA的求解能力,NEH-IGA算法在求解RHFS-TWC问题方面优势明显.     

求解置换流水车间调度问题的改进遗传算法

针对置换流水车间调度问题的基本特征和传统遗传算法易早熟的缺陷,设计了改进遗传算法来求解此问题。采用NEH和Palmer启发式算法进行种群初始化,以提高初始解的质量;根据Metropolis准则对染色体进行选择操作,避免陷入局部最优;在变异过程中引入禁忌算法,避免迂回搜索;在算法迭代过程中引入了保优机制,避免丢失优秀染色体的基因信息;采用自适应终止准则,以保证解的质量。基于典型Benchmark算例的仿真实验结果表明,算法在求解质量和收敛速度方面明显优于NEH算法和种群经过初始优化的传统遗传算法。     

离散和声求解带启动时间批量流水线调度问题

分别在有等待和无等待的情况下,深入分析了带有启动时间的批量调度问题,以最小化最大完成时间为目标,提出了两种离散和声搜索算法。针对算法本质连续而问题离散的矛盾,对和声搜索算法进行改进。首先提出了基于工序的编码方式,采用inver-over和重组两种离散算子产生候选解的进化机制;并利用改进的NEH(Nawaz-Enscore-Ham)方法进行初始化,产生的高质量和多样化的初始种群有效地指导了算法的进化方向,提高收敛速度;最后将一种简单而有效的局部邻域搜索方法嵌入到和声搜索算法中以增强其局部搜索能力。仿真实验和比较结果表明了所提算法的有效性。     

An effective hybrid PSO-based algorithm for flow shop scheduling with limited buffers

In this paper, an effective hybrid algorithm based on particle swarm optimization (HPSO) is proposed for permutation flow shop scheduling problem (PFSSP) with the limited buffers between consecutive machines to minimize the maximum completion time (i.e., makespan). First, a novel encoding scheme based on random key representation is developed, which converts the continuous position values of particles in PSO to job permutations. Second, an efficient population initialization based on the famous Nawaz–Enscore–Ham (NEH) heuristic is proposed to generate an initial population with certain quality and diversity. Third, a local search strategy based on the generalization of the block elimination properties, named block-based local search, is probabilistically applied to some good particles. Moreover, simulated annealing (SA) with multi-neighborhood guided by an adaptive meta-Lamarckian learning strategy is designed to prevent the premature convergence and concentrate computing effort on promising solutions. Simulation results and comparisons demonstrate the effectiveness of the proposed HPSO. Furthermore, the effects of some parameters are discussed.     

蛙跳优化算法求解多目标无等待流水线调度

提出了基于Pareto边界和档案集的改进蛙跳算法,解决以最大完工时间、最大拖后时间和总流经时间为目标值的无等待流水线调度问题．首先,采用NEH（Nawaz—Enscore—Ham）启发式与随机解相结合的初始化方法,保证了初始群体的质量和分布性;其次,采用两点交叉方法生成新解,使蛙跳算法能够直接用于解决调度问题;再次,利用非支配解集动态更新群体,改善了群体的质量和多样性;最后,将基于插入邻域的快速局部搜索算法嵌入到蛙跳算法中,增强了算法的开发能力和效率．仿真试验表明了所得蛙跳算法的有效性和高效性．     

An improved NEH heuristic to minimize makespan in permutation flow shops

For over 20 years the NEH heuristic of Nawaz, Enscore, and Ham [A heuristic algorithm for the m-machine, n-job flow-shop sequencing problem. Omega, The International Journal of Management Science 1983;11:91–5] has been commonly regarded as the best heuristic for solving the NP-hard problem of minimizing the makespan in permutation flow shops. The strength of NEH lies mainly in its priority order according to which jobs are selected to be scheduled during the insertion phase. Framinan et al. [Different initial sequences for the heuristic of Nawaz, Enscore and Ham to minimize makespan, idle time or flowtime in the static permutation flowshop problem. International Journal of Production Research 2003;41:121–48] presented the results of an extensive study to conclude that the NEH priority order is superior to 136 different orders examined. Based upon the concept of Johnson's algorithm, we propose a new priority order combined with a simple tie-breaking method that leads to a heuristic that outperforms NEH for all problem sizes.     

An improved NEH-based heuristic for the permutation flowshop problem

NEH is an effective heuristic for solving the permutation flowshop problem with the objective of makespan. It includes two phases: generate an initial sequence and then construct a solution. The initial sequence is studied and a strategy is proposed to solve job insertion ties which may arise in the construct process. The initial sequence which is generated by combining the average processing time of jobs and their standard deviations shows better performance. The proposed strategy is based on the idea of balancing the utilization among all machines. Experiments show that using this strategy can improve the performance of NEH significantly. Based on the above ideas, a heuristic NEH-D (NEH based on Deviation) is proposed, whose time complexity is O(mn²), the same as that of NEH. Computational results on benchmarks show that the NEH-D is significantly better than the original NEH.     

On insertion tie-breaking rules in heuristics for the permutation flowshop scheduling problem

The most efficient approximate procedures so far for the flowshop scheduling problem with makespan objective – i.e. the NEH heuristic and the iterated greedy algorithm – are based on constructing a sequence by iteratively inserting, one by one, the non-scheduled jobs into all positions of an existing subsequence, and then, among the so obtained subsequences, selecting the one yielding the lowest (partial) makespan. This procedure usually causes a high number of ties (different subsequences with the same best partial makespan) that must be broken via a tie-breaking mechanism. The particular tie-breaking mechanism employed is known to have a great influence in the performance of the NEH, therefore different procedures have been proposed in the literature. However, to the best of our knowledge, no tie-breaking mechanism has been proposed for the iterated greedy. In our paper, we present a new tie-breaking mechanism based on an estimation of the idle times of the different subsequences in order to pick the one with the lowest value of the estimation. The computational experiments carried out show that this mechanism outperforms the existing ones both for the NEH and the iterated greedy for different CPU times. Furthermore, embedding the proposed tie-breaking mechanism into the iterated greedy provides the most efficient heuristic for the problem so far.