模拟植物生长算法与知识创新的几点思考

讨论了知识DNA的跨域映射思想.基于这种思想,对模拟植物生长算法(PGSA)的理论体系和应用案例进行了分析.PGSA是以植物向光性理论为启发式准则的智能算法,该算法在各领域中的应用情况表明,知识DNA(如植物生长、遗传变异、蚂蚁觅食、鸟群捕食、固体退火等规律的知识)的跨领域映射对于智能算法的创新具有一定的现实意义.     

并行设备上的差异作业批调度问题及多项式算法

考虑了一类作业尺寸有差异的批调度问题,加工环境为并行批处理设备.以制造跨度为优化目标,建立了基于整数规划的数学模型;分析了制造跨度最小化问题的计算复杂性,给出问题可行解规模的上下界;然后设计了一种基于LPT规则和Batch First Fit规则的近似算法,证明了算法的时间性能为O(nlogn),算法在优化制造跨度时的最坏性能比为(8/3～2/3m).     

差异分批模式下的联合成本优化问题及算法

提出了一类制造企业的联合成本优化问题,将企业的产品制造环节和配送环节进行协同运作,实现供应链环境下的联合调度.在生产环节,考虑一类典型的差异分批制造模式,即待加工的作业尺寸有差异,而批处理设备的容量确定,设备环境为多台并行设备;在配送环节,企业采用自有车辆进行运输,车辆具有相同的运输能力;若完工的作业在当前无可用车辆进行配送,则转入产成品库存;联合成本为生产、库存和配送三阶段的总成本.本文首先构造了基于整数规划的数学模型,证明了联合成本的最小化问题是强NP-hard问题;然后设计了多项式时间的近似算法,分析了算法的时间复杂性,并证明了算法的求解性能.     

考虑人车混采的道路信息采集的路径规划研究

本文考虑了道路信息外业采集的任务要求,人车混采的采集方式以及路网特性等方面,为道路信息采集人员的路径规划建立了满足人车混采约束的整数规划模型;提出了分阶段的转化算法,将其逐步转化为有限时间容量限制的弧路径问题(TCARP)。TCARP问题是一种NP-hard问题,精确求解算法无法在合理时间内得到问题的最优解,因此本文设计了求解TCARP问题的两种快速启发式算法TPS和TUH及其随机化版本;考虑到实际采集问题的大规模特性,在两种快速启发式算法的基础上构造GRASP-PA寻优算法。最后分别结合不同规模的基准算例和实际采集算例证明了本文所构造的算法的有效性。     

单资源调度中误工问题的作业时间压缩算法

本文采用作业时间可压缩的方法来解决单资源调度中的误工问题。在安排任务处理顺序的过程中,当某个任务发生误工时,我们基于关键路径反向搜索的方法,给出了一个启发式算法,求得需要压缩的任务集,使这个误工任务的延误时间尽可能的减少,并使需要压缩的任务数目最少,最后证明了算法的有效性,并给出了一个算例。     

具有缓冲区约束的流水车间调度问题综述

首先介绍了具有缓冲区约束的流水车间调度问题的一般框架、算法及其分类,主要针对启发式算法进行分析和总结,并进一步介绍了如何合理设置缓冲区以及存储时间有限的情况,最后,探讨了在此研究领域中的未来发展趋势.     

多阶段网络扩张投资模型研究

在总体网络布局规划完成的前提下分析网络各边的构建时间和先后顺序.在给定的规划网络 G(V,A,G)中,有 r 对 O-D 用户流,在总的网络建设费用、维护费用及用户流成本最小的目标下分析各阶段投资方案的选择问题.模型以各种费用的现值为基础讨论了模型的变化情况,并给出了基于贪婪的启发式算法.最后以巩义市道路网的建设规划为例进行了分析,实例显示,该模型和算法为巩义市的道路网规划节约了数千万元的社会成本,增加了近亿元的直接社会经济效益.     

供应网络中越库转运中心仓门分配问题研究

本文探讨一种带有时间窗口的仓门分配问题--车辆在转运中心进行货物装却作业时如何在其时间窗口限制内有效的分配有限的仓门资源,以达到最佳运作效率.以往的研究结果表明该问题是强NP难题,因此本文针对该问题的特殊结构,提出一种新颖的整合了贪婪算法、遗传算法以及禁忌算法思想的混合启发式算法来有效的解决该问题.我们并将该混合启发式算法与遗传算法、禁忌算法以及CPLEX这三种方式的求解效果进行对比,其数值实脸结果表明混合启发式算法在求解效果上有明显的优势.     

等待时间受限的置换流水车间调度启发式算法

针对等待时间受限的置换流水车间调度问题,分析了其可行解与流水车间调度最优解的关系,给出了计算最大完工时间的有向图,证明了等待时间受限的置换流水车间调度问题的可逆性,并以此为基础提出了一种启发式算法.算法首先根据等待时间受限约束与无等待(no-wait)约束的相似特征,生成初始工件序列集;然后利用问题可逆性给出了复杂度为O(n2m)的插入优化机制,进一步优化初始解.数据实验的结果验证了启发式算法的可行性和有效性.     

生态旅游区固体废弃物回收的模糊优化模型

研究了生态旅游区固体废弃物逆向物流网络设计问题,包括中转站和处理站的2级选址.建立了成本最小和处理站距人们的最小距离最大化的双目标整数规划模型.考虑到废弃物产生量具有不确定性,提出了带有模糊参数的中转站和处理站选址的模糊优化模型,并用启发式算法给予求解.最后给出一个算例证明了算法的有效性和可行性.     

Scheduling a single semi-continuous batching machine

This paper addresses a new problem, called semi-continuous batch scheduling, which arises in the heating-operation of tube-billets in the steel industry. Each heating furnace can be regarded as a semi-continuous batching machine, which can handle up to C jobs simultaneously. The jobs in the same batch enter and leave the machine semi-continuously, which differs from the traditional batching machine scheduling where the jobs in same batch have a starting time and a finishing time. In this paper the processing time of a batch depends on the capacity of the semi-continuous batching machine, the longest processing time of jobs in the batch and its size. The objectives are to schedule jobs on the machine so that the makespan and the total completion time are minimized. A schedule for a semi-continuous batching machine consists of a batching and sequencing for the batches. We propose the optimal properties of two different objective functions and present the different dynamic programming algorithms with a running time of O(n²), respectively.     

Single machine batch scheduling with release times

Motivated by a high-throughput logging system, we investigate the single machine scheduling problem with batching, where jobs have release times and processing times, and batches require a setup time. Our objective is to minimize the total flow time, in the online setting. For the online problem where all jobs have identical processing times, we propose a 2-competitive algorithm and we prove a corresponding lower bound. Moreover, we show that if jobs with arbitrary processing times can be processed in any order, any online algorithm has a linear competitive ratio in the worst case. A preliminary version of a part of this paper was presented at the 31st International Symposium on Mathematical Foundations of Computer Science (MFCS 2006). We gratefully acknowledge reviewers’ comments that helped to improve the presentation of this work. Supported by the Swiss SBF under contract no. C05.0047 within COST-295 (DYNAMO) of the European Union. Research carried out while B. Weber was affiliated with the Institute of Theoretical Computer Science, ETH Zurich.     

Maximum latency scheduling problem on two-person cooperative games

This paper studies a two-person cooperative game in which a set of jobs has to be processed jointly by two people. Each of them has a single machine and his processing cost is defined as the minimum value of the maximum latency of his negotiably assigned jobs. The objective is to maximize the multiplication of their rational positive cooperative profits. In the case where all jobs have the same processing time, if they have a common due date, the problem is polynomial-time solvable; if due dates can be different, there exits an optimal schedule in which the jobs assigned to each person are scheduled in Earlier Due Date first (EDD) order and a polynomial-time dynamic programming is further proposed. In the case where processing times can be different, the NP-completeness of this problem is proved, and a pseudo-polynomial-time dynamic programming algorithm is developed.     

Non-resumable scheduling on a single bounded parallel-batch machine with periodic maintenance

We consider the problem of scheduling a set of jobs with different processing times and sizes on a single bounded parallel-batch machine with periodic maintenance. Because the machine is in batch-processing model and the capacity is fixed, several jobs can be processed simultaneously in a batch provided that the total size of the jobs in the batch doesn’t exceed the machine capacity. And the processing time of a batch is the largest processing time of the jobs contained in the batch. Meanwhile, the production of each batch is non-resumable, that is, if a batch cannot be completed processing before some maintenance, that batch needs to be processed anew once the machine returns available. Our goal is to minimize the makespan. We first consider two special cases where the jobs have the same sizes or the same processing times, both of which are strongly NP-hard. We present two different approximation algorithms for them and show that these two algorithms have the same tight worst-case ratio of 2. We then consider the general case where the jobs have the arbitrary processing times and arbitrary sizes, for which we propose a 17/5-approximation algorithm.

     

加权折扣单机排序干扰管理模型和算法研究

为解决机器排序中由于干扰事件的发生使初始最优加工时间表无法按计划执行的问题,构建同时考虑原目标和扰动目标的双目标干扰管理模型,对初始最优加工时间表进行调整并对未完工工件进行重排序;在双目标干扰管理模型中,原目标由所有工件的加权折扣完工时间和来度量,扰动目标由重排序后工件完工时间的变化来度量;结合量子比特在表示解的多样性方面的优点和非支配排序遗传算法在处理多目标排序问题上的优点,设计一种量子遗传算法和非支配排序遗传算法相结合的启发式进化算法对构建的模型进行求解。在数值算例中,通过比较若干项针对有效解集的性能指标发现,该混合算法求得的有效解集在多样性和与最优有效前沿的邻近性等方面优于目前得到广泛应用的非支配排序遗传算法,验证了构建的模型和算法对于求解机器排序干扰管理问题的有效性。     

2-Distance vertex-distinguishing index of subcubic graphs

This paper addresses the performance of scheduling algorithms for a two-stage no-wait hybrid flowshop environment with inter-stage flexibility, where there exist several parallel machines at each stage. Each job, composed of two operations, must be processed from start to completion without any interruption either on or between the two stages. For each job, the total processing time of its two operations is fixed, and the stage-1 operation is divided into two sub-parts: an obligatory part and an optional part (which is to be determined by a solution), with a constraint that no optional part of a job can be processed in parallel with an idleness of any stage-2 machine. The objective is to minimize the makespan. We prove that even for the special case with only one machine at each stage, this problem is strongly NP-hard. For the case with one machine at stage 1 and m machines at stage 2, we propose two polynomial time approximation algorithms with worst case ratio of \(3-\frac{2}{m+1}\) and \(2-\frac{1}{m+1}\), respectively. For the case with m machines at stage 1 and one machine at stage 2, we propose a polynomial time approximation algorithm with worst case ratio of 2. We also prove that all the worst case ratios are tight.     

Semi-online scheduling for jobs with release times

In this paper we consider three semi-online scheduling problems for jobs with release times on m identical parallel machines. The worst case performance ratios of the LS algorithm are analyzed. The objective function is to minimize the maximum completion time of all machines, i.e. the makespan. If the job list has a non-decreasing release times, then $2-\frac{1}{m}$ is the tight bound of the worst case performance ratio of the LS algorithm. If the job list has non-increasing processing times, we show that $2-\frac{1}{2m}$ is an upper bound of the worst case performance ratio of the LS algorithm. Furthermore if the job list has non-decreasing release times and the job list has non-increasing processing times we prove that the LS algorithm has worst case performance ratio not greater than $\frac{3}{2} -\frac{1}{2m}$ .     

Minimizing the Number of Late Jobs under the Group Technology Assumption

We consider the one-machine scheduling problem to minimize the number of late jobs under the group technology assumption, where jobs are classified into groups and all jobs from the same group must be processed contiguously. This problem is shown to be strongly NP-hard, even for the case of unit processing time and zero set-up time. A polynomial time algorithm is developed for the restricted version in which the jobs in each group have the same due date. However, the problem is proved to be ordinarily NP-hard if the jobs in a group have the same processing time as well as the same due date.     

混合离散差分进化算法在单机批处理调度中的应用

本文研究单机批处理调度问题,批处理机有批次容量限制,批处理时间由每个批次所含作业中的最长作业处理时间决定。每个作业具有不同的大小、处理时间、提前拖期惩罚权重,所有作业具有公共交货期,且交货期无限晚。目标函数为最小化所有作业的加权提前拖期惩罚之和。该问题已被证明为NP难题,本研究找到了其最优解具有的一些性质,在此基础上利用它们提出了一种动态规划(DP)与差分进化(DE)算法相结合的混合离散差分进化(HDDE)算法来求解该问题,通过与传统的遗传算法、模拟退火算法和迭代贪婪算法进行对比,HDDE算法显示了更加强大的全局搜索能力。     

一种差异工件单机批调度问题的蚁群优化算法

由于在利用蚁群算法构建差异工件(即工件有尺寸差异)单机批调度问题的解时,批的加工时间是不确定的.从而不能类似于经典调度问题的蚁群算法把批加工时间的倒数作为蚁群算法中的启发式信息,引入批的利用率和批的负载均衡率作为蚁群算法中的启发式信息,提出了JACO(ant colony optimization based a job sequence)和BACO(ant colony optimization based a batch sequence)两种蚁群优化算法.在算法JACO中,解的编码为工件序列,它对应着用BF(best fit)分批规则生成的调度方案,信息素代表工件间的排列顺序;在算法BACO中,解的编码为批序列,信息素代表工件间的批相关性,由此信息素通过中间信息素量来构造相应的解,并引入特定的局部优化策略,提高了算法的搜索效率.实验表明,与以往文献中的SA(simula-ted annealing)、GA(genetic algorithm)算法以及FFLPT(first-fit longest processing time)、BFLPT (best-fit longest processing time)启发式规则相比,算法JACO和BACO明显优于它们,且BACO算法比JACO算法效果更好.