使用遗传算法改进R_时刻表算法

给出了对于多成分R_时间表的解决办法.利用集合的性质把它看成是几个单成分时间关系约束的并集,采用算法Ⅰ将多成分分解成单成分.使用遗传算法把问题的多成分的时间关系作为染色体的基因位,问题的所有的多成分的时间关系就构成了算法的染色体,以求解关系矩阵中求到的相容子集的个数作为染色体的适应度.算法的终止条件是根据关系矩阵求得的相容子集数等于事件的个数,利用算法Ⅱ使用遗传算法求解多成分时间规划问题.对实际的问题进行了讨论,使用该算法在有穷次迭代后可得到可行解.     

基于混合遗传算法的时间最优控制问题求解

研究了用混合遗传算法求解时间最优控制问题.混合遗传算法是用粒子群位移转移的思想改变遗传算法的变异规则,通过记录各染色体的历史最优值和种群的最优值,来修正下一代的染色体,新的算法保留了遗传算法的选择和交叉操作,保证了遗传算法强大的全局搜索性能,该算法可求解数学优化问题.在分析时间最优控制问题已有求解方法优缺点的基础上,提...     

带时间窗车辆路径问题的多目标文化基因算法

针对物流配送中带时间窗的车辆路径问题,以最小化车辆使用数和行驶距离为目标,建立了多目标数学模型,提出了一种求解该问题的多目标文化基因算法。种群搜索采用遗传算法的进化模式和Pareto排序的选择方式,局部搜索采用禁忌搜索机制和存储池的结构,协调两者得到的Pareto非占优解的关系。与不带局部搜索的多目标遗传算法和单目标文化基因算法的对比实验表明,本文算法的求解质量较高。     

基于HGA的最小旅行时间多旅行商问题研究

为了解决最小化旅行时间的多旅行商一类问题,提出了一种递阶遗传算法和矩阵解码方法。该算法根据问题的特点,采用一种递阶编码方案,此编码与多旅行商问题一一对应。用递阶遗传算法优化多旅行商问题不需设计专门的遗传算子,操作简单,并且解码方法适于求解距离矩阵对称和距离矩阵非对称的多旅行商问题。计算结果表明,递阶遗传算法是有效的,能适用于优化最小化完成时间的多旅行商问题。     

微分进化求解无线传感器网络中的覆盖问题

研究使用微分进化算法求解无线传感器网络中的覆盖问题,介绍一种通用的无线传感器网络覆盖问题数据集生成算法,利用该算法生成覆盖问题数据集.提出利用微分进化算法求解覆盖问题的方法,方法的重组操作保证至少一个关键点的传感器分配到不同的子集,提高解的质量.其适应度函数考虑了完全覆盖子集的个数和非完全覆盖子集的覆盖率.与此类经典算法进行对比实验,实验结果表明了该方法的有效性.     

普适计算中一种最优服务选择算法的设计与仿真*

详细分析了服务选择问题及其求解目标,综合服务提供方高效率低成本和终端用户方的服务质量（QoS）等目标约束条件,提出一种多目标约束的最优服务选择遗传算法。该算法采用矩阵描述服务提供方、服务、终端用户三者之间的关系,并采用矩阵编码方式,将矩阵视为染色体个体,将矩阵的列视为染色体基因。仿真实验结果表明,该算法具有较好的收敛性和稳定的寻优能力。     

基于改进遗传算法的连锁便利店配送路径优化

提出一种针对软时间窗下连锁便利店配送路径规划的带时间窗口的多染色体遗传算法。为解决单车场多车型带密集半软时间窗问题,讨论解决方案预防其陷入局部最优解。对于上述配送路径问题,提出多染色体改进遗传算法在减少车辆运输成本、惩罚成本的目标下进行最优路径求解,并为连锁便利店的路径规划案例提出车辆与路径选择的优化方案,最后将该算法与传统遗传算法进行实验对比分析。实验结果表明,本文算法在密集半软时间窗下,相比传统遗传算法明显减少了总配送成本,从而验证了本文算法的有效性。     

R_时刻表及其应用

求解R-时刻表是一个NP难问题,文中改进了一种有效的求解R-时刻表的时间规划算法并加以实现。该算法是建立在Allen的时间世界模型基础上,利用时间关系的关系矩阵方法来得到一致满足所有时间关系约束R-时刻表的一种算法。利用该算法实现了一个简化运动会项目的安排,验证了算法的有效性和实用性。     

灾变遗传算法求解带时间窗的车辆调度问题

提出一种可以有效求解带时间窗的车辆调度问题的灾变遗传算法.遗传算法作为一种高效的启发式算法被用于解决这类组合优化问题,但是该算法存在过早收敛、易陷入局部最优等缺陷.针对此问题,在搜索过程中采用灾变算子使遗传算法跳出局部最优,并针对车辆调度问题设计一种可以直接产生可行解的交叉算子,避免染色体交叉过程中产生不可行的子代.通过仿真算例验证了所提出的算法求解带时间窗的车辆调度问题的有效性;通过与标准遗传算法、改进遗传算法和粒子群算法的比较,进一步验证了灾变遗传算法在优化性能以及算法鲁棒性方面的优势.     

带有时间窗的多配送中心车辆调度问题研究

在分析时间窗的惩罚函数基础上,建立了带有时间窗的多配送中心车辆调度模型,针对模型设计了两阶段求解算法,先通过扫描算法把客户化分到不同的配送中心负责配送,然后采用改进的遗传算法求解带有时间窗的单配送中心的车辆调度模型,最后,结合算例仿真计算验证了算法的有效性。     

带时间窗的同时集散货物路线问题研究

研究了业务繁忙环境下带时间窗的同时集散货物路线问题．以车辆数、运输距离和完成运输任务的总 时间最小为目标建立了多目标模型,提出用基于路线集合划分的分解迭代算法求解该问题．该算法首先用两种策略 将问题的解分解为几个子集合,用记录更新法分别求解每个子集合,将子集合求得的最好路线反馈回来形成新的当 前解,再分解迭代,逐渐改善解的质量．最后数据实验表明该算法能有效解决带时间窗的单向车辆路线问题和集散 一体化的双向车辆路线问题．     

Genetic algorithm for minimizing the total weighted completion time scheduling problem with learning and release times

This paper considers a single-machine problem with the sum-of-processing time based learning effect and release times. The objective is to minimize the total weighted completion times. First, a branch-and-bound algorithm incorporating with several dominance properties and two lower bounds are developed for the optimal solution. Then a genetic heuristic-based algorithm is proposed for a near-optimal solution. Finally, a computational experiment is conducted to evaluate the performances of the proposed algorithms. The results show that the branch-and-bound algorithm can solve instances up to 15 jobs, and the average error percentage of the genetic heuristic algorithm is less than 0.105%.     

云计算环境下利用改进遗传算法结合二次编码的大规模资源调度方法

针对传统遗传算法无法满足多用户下的大规模云计算环境下的资源调度问题,提出利用改进遗传算法结合二次编码的方法解决大规模资源调度。首先,在选择复制阶段,采用基于最小任务完成时间和匹配程度的双适应度函数,对种群以双重标准进行筛选。然后,对算法的交叉变异概率进行了自适应优化,使其自适应能力进一步提高,保证了算法尽快向最优解收敛。同时引入的收敛终止条件保证了算法尽快跳出循环。最后,在CloudSim平台上对改进遗传算法（IGA）进行了分析,实验结果表明,提出的改进遗传算法能够很好地适用于大规模资源调度,且结果优于其他几种较新的对比算法。     

文化基因算法在第四方物流路径规划中的应用

第四方物流路径问题是复杂的组合优化问题。基本遗传算法在第四方物流路径问题上存在随着问题规模扩大,算法的成功率和准确率不断下降等缺点。针对基本的遗传算法已经不能满足规模较大的第四方物流问题等缺点,结合实验分析,提出了一种以遗传算法为全局搜索策略的文化基因算法,并针对第四方物流的问题特点设计了相应的局部搜索策略。实验结果表明,与基本遗传算法相比,该混合算法不仅在求解质量上有了较大的改进,并且在大规模第四方物流问题上也能获得质量较好的解,算法的成功率和准确率明显高于基本的遗传算法。因此,基于遗传算法的文化基因算法是解决大规模第四方物流路径问题的一种有效方法。     

移动云环境面向多重服务选择的计算卸载算法

移动云计算可以通过计算卸载改善移动设备的能效和应用的执行延时。然而面对云端的多重服务选择时,计算卸载决策是NP问题。为了解决这一问题,提出一种遗传算法寻找计算卸载的最优应用分割决策解。遗传种群初始化中,算法联立预定义和随机染色体方法进行初始种群的生成,减少了无效染色体的发生比例。同时,算法为预定义的预留种群设计一种特定的基于汉明距离函数的适应度函数,更好地衡量了染色体间的差异。种群交叉中分别利用近亲交配与杂交繁育丰富了种群个体。算法通过修正的遗传操作减少了无效解的产生,以更合理的时间代价获得了应用分割的最优可行解。应用现实的移动应用任务图进行仿真实验评估了算法效率。评估结论表明,所设计的遗传算法在应用执行能耗、执行时间以及综合权重代价方面均优于对比算法。     

遗传算法求解完全欺骗性问题的平均计算时间

讨论了一类遗传算法求解完全欺骗性问题的平均计算时间,证明了这类算法的平均计算时间是问题规模的指数次方,同时指出存在一种基于多重结构的遗传算法,它求解这个问题的２计算时间是问题规模的多项式次方。     

Modeling rolling batch planning as vehicle routing problem with time windows

This paper considers the rolling batch planning problem of grouping and sequencing a given set of slabs into several rolling units in iron and steel industry. The existing mathematical methods often used for the problem are traveling salesman problem (TSP) and vehicle routing problem (VRP), but these methods are not precise, because the position limitation of some slabs in a rolling unit scheduling is not considered. Therefore we suggest a new model, vehicle routing problem with time window (VRPTW) to describe the rolling batch planning problem, in which the position limitation of slabs are quantified as the time constraints. Several solution methods including the genetic algorithm are presented for solving the problem and the computational results show that the genetic algorithm is superior to other methods.In this paper, the vehicle routing problem with time window (VRPTW) of combinational optimization is used to analyze and model the rolling batch planning problem. Genetic algorithm and heuristic are used to solve the problem. Simulation results based on the actual production data show that this model is precise and the genetic algorithm based method is very promising.     

Linear-Time Algorithms for Partial \boldmathk -Tree Complements

It is known that a graph decision problem can be solved in linear time over partial k -trees if the problem can be defined in Monadic Second-order (or MS) logic. MS logic allows quantification of vertex and edge subsets, with respect to which logical sentences can encode many different conditions that an input graph must satisfy. It is not always clear, however, which graph problems can be expressed in such a way. In this paper we consider problems stated as logical conditions on subsets of the vertices and nonedges of the input graph. If such a problem can be defined in MS logic (i.e., in terms of the vertices and edges of the input graph), then there is a linear-time algorithm to solve the problem over partial k -trees. This algorithm also provides a solution to some problem over the graph-theoretic complements of partial k -trees. We study several examples of these ``complement-problems.' We introduce a variation of MS logic in which, if a graph-problem can be defined over the class of partial k -tree complements, then there is a linear-time algorithm to solve that problem over partial k -tree complements, and (equivalently) a linear-time algorithm to solve its complement-problem over partial k -trees.     

Parallel genetic algorithms: a survey and problem state of the art

In relation with development of computer capabilities and the appearance of multicore processors, parallel computing made it possible to reduce the time for solution of optimization problems. At present of interest are methods of parallel computing for genetic algorithms using the evolutionary model of development in which the main component is the population of species (set of alternative solutions to the problem). In this case, the algorithm efficiency increases due to parallel development of several populations. The survey of basic parallelization strategies and the most interesting models of their implementation are presented. Theoretical ideas on improvement of existing parallelization mechanisms for genetic algorithms are described. A modified model of parallel genetic algorithm is developed. Since genetic algorithms are used for solution of optimization problems, the proposed model was studied for the problem of optimization of a multicriteria function. The algorithm capabilities of getting out of local optima and the influence of algorithm parameters on the deep extremum search dynamics were studied. The conclusion on efficiency of application of dynamic connections of processes, rather than static connections, is made. New mechanisms for implementation and analysis of efficiency of dynamic connections for distributed computing in genetic algorithms are necessary.     

Representing lattices using many-valued relations

This paper provides a representation theorem of lattices using many-valued relations. We show that any many-valued relation can be associated to a unique lattice which is a meet-sublattice of a product of chains. Conversely, to any lattice we can associate a many-valued relation such that its associated lattice is isomorphic to the initial one. Thereby, we obtain a representation theorem of lattices using many-valued relations. Moreover, since several many-valued relations might have the same associated lattice, we give a characterization of the minimal many-valued relation that can be associated to a lattice. We then sketch a polynomial time algorithm which computes such a minimal relation from either a lattice or an arbitrary relation. This representation presents several advantages: it is smaller than the usual binary representation; all known reconstruction algorithms working on binary relation can be used without loss of efficiency; it can be used by existing data mining processes.