面向大学课程时间表的并行多视图搜索算法

针对大学课程时间表问题,提出一种基于改进迭代局部搜索的并行多视图搜索算法进行求解。依据课程时间表问题特性设计包含八种基础邻域的多邻域集,并根据提升速度比制定基邻域选择概率设置规则。在迭代局部搜索过程中,运用多视图学习策略对多个局部搜索步骤进行视图共享,及时调整搜索方向以提升搜索效率。通过并行计算思想对算法优化,提升多视图搜索的收敛速度。实验结果表明,提出的算法求解精度更佳,且具有优异的扩展性和并行效率。     

多目标相关性指派问题的模拟退火算法

讨论了一种较复杂的指派问题—多目标相关性指派问题的模型,通过对搜索操作和参数的合理设置,提出一类求解多目标相关性指派问题Pareto最优解的模拟退火算法,并通过实际运算证明该算法是有效的。     

虚拟养老服务人员调度多目标优化研究

针对虚拟养老服务人员调度问题，分析老人、虚拟养老服务中心和服务人员的利益追求，以成本最优、老人和服务人员满意度最大为主要考量因素来构建多目标优化模型。设计了离散化多目标鲸鱼优化算法。通过改进传统鲸鱼优化算法的鲸鱼位置更新公式和局部搜索算子，引入非支配排序用于求解构建的多目标优化问题。通过求解算例并将结果同NSGA-II和NSGA-III对比，验证算法的优越性。该研究综合考虑三者的利益，可为虚拟养老服务人员调度提供丰富的决策集合。     

一种实时多目标路径规划方法

提出一种利用实时搜索思想的多目标路径规划方法.首先设计并实现局部路径规划算法,在有限的局部空间内执行启发式搜索,求解所有局部非支配路径;在此基础上,提出实时多目标路径规划方法,设计并实现相应的启发式搜索算法,在线交替执行局部搜索过程、学习过程与移动过程,分别用于求解局部空间内的最优移动路径,完成状态的转移和更新状态的启发信息,最终到达目标状态.研究表明,实时多目标启发式搜索算法通过限制局部搜索空间,避免了大量不必要的计算,提高了搜索效率,能够高效地求解多目标路径规划问题.     

状态定义粒子群算法在非线性方程组中的应用

提出了一种新颖的状态定义粒子群优化算法。该算法针对粒子群算法容易陷入局部最优和搜索精度不高的缺点,结合爬山算法和粒子群算法的特点,根据粒子状态的实时更新采用不同的搜索方法,在迭代过程中搜索到尽可能多的局部最优解,从而使算法可以更容易地跳出局部最优,更高效地搜索到全局最优解。对测试函数和非线性方程组求解问题进行实例仿真,仿真结果验证了算法的有效性,具有一定的实际应用价值。     

文化基因算法在多约束背包问题中的应用

文化基因算法是一种启发式算法,与一些经典数学方法相比,更适于求解多约束背包问题.文化基因算法是一种基于种群的全局搜索和基于个体的局部启发式搜索的结合体,针对多约束问题,提出采用贪婪策略通过违反度排序的方法处理多约束条件,全局搜索采用遗传算法,局部搜索采用模拟退火策略,解决具有多约束条件的0-1背包问题.通过对几个实例的求解,表明文化基因算法与标准遗传算法相比,具有更优的搜索性能.     

基于混合微粒群优化的多目标柔性Job-shop调度

应用传统方法求解多目标柔性Job-shop调度问题是十分困难的,微粒群优化采用基于种群的搜索方式,融合了局部搜索和全局搜索,具有很高的搜索效率.模拟退火算法使用概率来避免陷入局部最优,整个搜索过程可由冷却表来控制.通过对这两种算法的合理组合,建立了一种快速且易于实现的新的混合优化算法.实例计算以及与其他算法的比较说明,该算法是求解多目标柔性Job-shop调度问题的可行且高效的方法.     

基于遗传算法和非线性规划求解信息交互的光伏阵列模型鲁棒参数辨识方法

对光伏阵列进行建模不仅可以研究温度、光照等因素对V-I特性曲线的影响,还可以用模型代替实际光伏阵列进行各种光伏实验,降低实验成本,节省实验时间;参数辨识可以使光伏阵列模型的参数值设置更精确,使其与实际值相一致;针对基于非线性规划的光伏阵列模型鲁棒参数辨识方法容易陷入局部搜索的问题,提出了遗传算法与非线性规划求解信息交互的鲁棒参数辨识方法;将遗传算法与非线性规划求解信息交互,既可以进行全局搜索,又可以进行局部搜索,以得到问题的全局最优解;通过仿真测试,使用该方法得到的结果均方误差降低了8倍,均方误差量级达到了1.0E-3,表明了该方法在光伏阵列模型参数辨识方面具有较高的精确度。     

基于记忆库拉马克进化算法的作业车间调度

多种群遗传算法相比遗传算法在性能上能够有所提高,但对具有较多局部最优解的作业车间调度问题,多种群遗传算法仍然难以改善易陷入局部最优解和局部搜索能力差的缺点.因此,提出了一种求解作业车间调度问题的新算法MGA-MBL(multi-population genetic algorithm based on memory-base and Lamarckian evolution for job shop scheduling problem).MGA-MBL在多种群遗传算法的基础上通过引入记忆库策略,不但使子种群间的个体可以进行信息交换,而且有利于保持整个种群的多样性;通过构造基于拉马克进化机制的局部搜索算子来提高多种群遗传算法中子种群进化的局部搜索能力.由于MGA-MBL采用了全局寻优能力较强的模拟退火算法对记忆库中的个体进行优化,从而缓解了多种群遗传算法易陷入局部最优解的问题,并提高了算法求解作业车间调度问题的性能.对著名的benchmark数据进行测试,实验结果证实了MGA-MBL在求解作业车间调度问题上的有效性.     

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。     

设备定位问题局部搜索算法的实验

讨论设备问题的局部搜索近似算法及其在实际计算中表现出的新性质。主要讨论局部搜索算法中初始解的产生方法,设备价值与服务价值大小对算法求解性能的影响。实验表明：约有99%以上的实例可直接利用局部搜索算法求得最优解;贪心算法产生初始解的局部搜索算法求解时间明显短于随机算法产生初始解的方法,但两者求解质量相当;设备价值和服务价值数值范围越大,局部搜索算法越容易求得最优解。     

The discrete Unconscious search and its application to uncapacitated facility location problem

In this paper a discrete variant of Unconscious search (US) for solving uncapacitated facility location problem (UFLP) is proposed. Unconscious search mimics the process of psychoanalytic psychotherapy in which the psychoanalyst tries to access the unconscious of a mental patient to find the root cause his/her problem, which is encapsulated in unconsciousness. Unconscious search is a multi-start metaheuristic which has three main stages, namely construction, construction review and local search. In construction phase a new solution is generated. In construction review the generated solution in construction phase is used to produce more starting points for using in the local search phase. The results of applying US to UFLP shows that this metaheuristic can determine high quality solutions in short processing time comparing to other heuristics.     

Sequential approximation optimization assisted particle swarm optimization for expensive problems

In this paper, an efficient sequential approximation optimization assisted particle swarm optimization algorithm is proposed for optimization of expensive problems. This algorithm makes a good balance between the search ability of particle swarm optimization and sequential approximation optimization. Specifically, the proposed algorithm uses the optima obtained by sequential approximation optimization in local regions to replace the personal historical best particles and then runs the basic particle swarm optimization procedures. Compared with particle swarm optimization, the proposed algorithm is more efficient because the optima provided by sequential approximation optimization can direct swarm particles to search in a more accurate way. In addition, a space partition strategy is proposed to constraint sequential approximation optimization in local regions. This strategy can enhance the swarm diversity and prevent the preconvergence of the proposed algorithm. In order to validate the proposed algorithm, a lot of numerical benchmark problems are tested. An overall comparison between the proposed algorithm and several other optimization algorithms has been made. Finally, the proposed algorithm is applied to an optimal design of bearings in an all-direction propeller. The results show that the proposed algorithm is efficient and promising for optimization of the expensive problems.     

Discrete particle swarm optimization based on estimation of distribution for polygonal approximation problems

The polygonal approximation is an important topic in the area of pattern recognition, computer graphics and computer vision. This paper presents a novel discrete particle swarm optimization algorithm based on estimation of distribution (DPSO-EDA), for two types of polygonal approximation problems. Estimation of distribution algorithms sample new solutions from a probability model which characterizes the distribution of promising solutions in the search space at each generation. The DPSO-EDA incorporates the global statistical information collected from local best solution of all particles into the particle swarm optimization and therefore each particle has comprehensive learning and search ability. Further, constraint handling methods based on the split-and-merge local search is introduced to satisfy the constraints of the two types of problems. Simulation results on several benchmark problems show that the DPSO-EDA is better than previous methods such as genetic algorithm, tabu search, particle swarm optimization, and ant colony optimization.     

Comparison of Stochastic Global Optimization Methods to Estimate Neural Network Weights

Training a neural network is a difficult optimization problem because of numerous local minima. Many global search algorithms have been used to train neural networks. However, local search algorithms are more efficient with computational resources, and therefore numerous random restarts with a local algorithm may be more effective than a global algorithm. This study uses Monte-Carlo simulations to determine the efficiency of a local search algorithm relative to nine stochastic global algorithms when using a neural network on function approximation problems. The computational requirements of the global algorithms are several times higher than the local algorithm and there is little gain in using the global algorithms to train neural networks. Since the global algorithms only marginally outperform the local algorithm in obtaining a lower local minimum and they require more computational resources, the results in this study indicate that with respect to the specific algorithms and function approximation problems studied, there is little evidence to show that a global algorithm should be used over a more traditional local optimization routine for training neural networks. Further, neural networks should not be estimated from a single set of starting values whether a global or local optimization method is used.     

An improved approximation approach incorporating particle swarm optimization and a priori information into neural networks

In this paper, an improved approach incorporating adaptive particle swarm optimization (APSO) and a priori information into feedforward neural networks for function approximation problem is proposed. It is well known that gradient-based learning algorithms such as backpropagation algorithm have good ability of local search, whereas PSO has good ability of global search. Therefore, in the improved approach, the APSO algorithm encoding the first-order derivative information of the approximated function is used to train network to near global minima. Then, with the connection weights produced by APSO, the network is trained with a modified gradient-based algorithm with magnified gradient function. The modified gradient-based algorithm can reduce input-to-output mapping sensitivity and lessen the chance of being trapped into local minima. By combining APSO with local search algorithm and considering a priori information, the improved approach has better approximation accuracy and convergence rate. Finally, simulation results are given to verify the efficiency and effectiveness of the proposed approach.     

Power law-based local search in spider monkey optimisation for lower order system modelling

The nature-inspired algorithms (NIAs) have shown efficiency to solve many complex real-world optimisation problems. The efficiency of NIAs is measured by their ability to find adequate results within a reasonable amount of time, rather than an ability to guarantee the optimal solution. This paper presents a solution for lower order system modelling using spider monkey optimisation (SMO) algorithm to obtain a better approximation for lower order systems and reflects almost original higher order system's characteristics. Further, a local search strategy, namely, power law-based local search is incorporated with SMO. The proposed strategy is named as power law-based local search in SMO (PLSMO). The efficiency, accuracy and reliability of the proposed algorithm is tested over 20 well-known benchmark functions. Then, the PLSMO algorithm is applied to solve the lower order system modelling problem.     

A Branch and Bound Algorithm for An Uncapacitated Facility Location Problem with a Side Constraint

In this paper, a branch and bound algorithm for solving an uncapacitated facility location problem (UFLP) with an aggregate capacity constraint is presented. The problem arises as a subproblem when Lagrangean relaxation of the capacity constraints is used to solve capacitated facility location problems. The algorithm is an extension of a procedure used by Christofides and Beasley (A tree search algorithm for the p-median problem. European Journal of Operational Research , Vol. 10, 1982, pp. 196–204) to solve p -median problems and is based on Lagrangean relaxation in combination with subgradient optimization for lower bounding, simple Lagrangean heuristics to produce feasible solutions, and penalties to reduce the problem size. For node selection, a jump-backtracking rule is proposed, and alternative rules for choosing the branching variable are discussed. Computational experience is reported.     

一种混合自适应多目标Memetic算法

Memetic算法是求解多目标优化问题最有效的方法之一,融合了局部搜索和进化计算,具有较高的全局搜索能力．混合自适应多目标Memetic算法（HAMA）用基于模拟退火的加权法进行局部搜索,采用Pareto法实现交叉和变异,通过扰动增强算法的exploration能力,且进化过程可根据改善率自适应调整,以提高搜索效率并改善算法的鲁棒性．算例测试说明HAMA能产生更接近Pareto前沿且多样性更好的近似集．