多策略改进的多目标粒子群优化算法

为了进一步提高多目标粒子群优化算法的收敛性和多样性,提出一种多策略改进的多目标粒子群优化算法.建立具有精英粒子领导的异构更新模式并设置个体学习增强因子项,促使种群能够快速寻找真实Pareto最优解.引入外部档案冗余机制,利用其变异及对种群的干扰策略增强解的多样性,避免算法早熟现象的发生.仿真实验结果表明,与其他几种优化算法相比,所提出的算法表现出较好的收敛性和多样性.     

基于QPSO 和拥挤距离排序的多目标量子粒子群优化算法

为了提高多目标优化算法的收敛性、分布性和减少算法的计算代价,提出一种基于量子行为特性的粒子群优化(QPSO)和拥挤距离排序的多目标量子粒子群优化(MOQPSO-CD)算法.MOQPSO-CD利用QPSO快速接近真实的Pareto最优解,同时引入高斯变异算子以增强解的多样性.采用拥挤距离排序的方法对外部存储器中最优解进行更新和维护,使得从中选择的具有全局最优的领导粒子能够引导粒子群最终找到真实的Pareto最优解.仿真结果表明,MOQPSO-CD具有更好的收敛性和更均匀的分布性.     

综合密度信息的矢量变异多目标粒子群优化

粒子群优化算法求解多目标优化问题存在早熟收敛和后期收敛速性差的不足,解的分布性也有待提高。为此设计一种新的多目标粒子群优化算法：对寻求粒子最优解的sigma方法进行改进,提出一种综合非支配解密度信息和sigma值的最优解求解机制。对变异粒子速度进行矢量扰动变异;对停滞粒子进行位置变异,有效避免算法的早熟收敛问题。测试结果表明,所提出的算法在收敛性和解的分布性、多样性方面较经典的算法具有明显的优势。     

混合分解的多目标粒子群优化算法

针对多目标粒子群算法全局最优值的选取缺陷以及多样性保留缺陷,提出了一种基于分解和拥挤距离的多目标粒子群优化算法(Smoeadpso).算法采用切比雪夫分解机制,将邻居向量对应的子问题的中的最优解来作为某个粒子全局最优值的候选解了更有效限制粒子飞行速度以避免粒子飞行超出解空间界限,引入了新的速度限制因子维持了种群多样性.本文算法与经典的多目标进化算法在10个测试函数上的对比结果表明, Smoeadpso求得的Pareto解集与真实Pareto解集的逼近程度有明显提升并且对于3目标问题求解的均匀性也比同类粒子群算法优秀.     

一种改进的多目标蜻蜓优化算法

提出了一种改进的多目标蜻蜓优化算法。通过引入混合变异算子增加种群的多样性,避免算法早熟现象的发生;采用基于拥挤距离的外部档案动态维护策略,使获得的Pareto最优解集具有更好的分布性。最后,使用多目标基准函数进行测试,并与基本多目标蜻蜓算法和基本多目标粒子群算法进行性能比较。实验结果表明,改进后的多目标蜻蜓优化算法提高了Pareto最优解集的收敛性和分布性。     

基于量子行为特性粒子群和自适应网格的多目标优化算法

为了能够找到更多真实的Pareto最优解和提高所求最优解的分布均匀性,提出了一种新型的基于量子行为特性粒子群优化和自适应网格的多目标量子粒子群优化算法.利用量子行为特性粒子群优化算法的寻优优势快速地接近真实的Pareto最优解,引入高斯变异算子增强搜索解的多样性.通过设置一个外部存储器保留搜索过程中找到的Pareto最优解,采用自适应网格法对外部存储器中最优解进行更新和维护操作,使得从中选择的领导粒子能够引导粒子群最终找到真实的Pareto最优解.仿真结果表明所提算法具有更好的收敛性能和更均匀的分布性能.     

基于局部搜索与混合多样性策略的多目标粒子群算法

为了提高算法的收敛性与非支配解集的多样性,提出一种基于局部搜索与混合多样性策略的多目标粒子群算法（LH-MOPSO）.该算法使用增广Lagrange乘子法对非支配解进行局部搜索以快速接近Pareto最优解;利用基于改进的Maximin适应值函数与拥挤距离的混合多样性策略对非支配解集进行维护以保留解的多样性,同时引入高斯变异算子以避免算法早熟收敛;最后针对多目标约束优化问题,给出一种有效的约束处理方法.实验研究表明该算法具有良好的优化性能.     

基于拥挤距离的动态粒子群多目标优化算法

提出了一种改进的基于拥挤距离的动态粒子群多目标优化算法。为提高粒子的全局搜索能力,提出了新的动态变化惯性权重和加速因子的方法。引进了拥挤距离排序方法维护外部精英集和更新全局最优值。为保持非劣解的多样性,采用了小概率变异机制,并根据种群的大小选择不同的变异概率。最后,把算法应用到5个典型的多目标测试函数并与其他算法进行比较。实验结果表明,该算法所得的Pareto解集有很好的收敛性和多样性。     

基于分解和差分进化的多目标粒子群优化算法

为了提高多目标优化算法解集的分布性和收敛性,提出一种基于分解和差分进化的多目标粒子群优化算法(dMOPSO-DE).该算法通过提出方向角产生一组均匀的方向向量,确保粒子分布的均匀性;引入隐式精英保持策略和差分进化修正机制选择全局最优粒子,避免种群陷入局部最优Pareto前沿;采用粒子重置策略保证群体的多样性.与非支配排序(NSGA-II)算法、多目标粒子群优化(MOPSO)算法、分解多目标粒子群优化(dMOPSO)算法和分解多目标进化-差分进化(MOEA/D-DE)算法进行比较,实验结果表明,所提出算法在求解多目标优化问题时具有良好的收敛性和多样性.     

多目标优化中带变异算子的灰色粒子群算法

针对如何在多目标优化过程中求解更好的Pareto解集,提出一种基于变异算子的灰色粒子群算法。该算法将灰色关联度应用于粒子群算法,且将方差的概念引入灰色关联度,以区分那些点关联系数有显著差异而其均值相等的各组序列。以此作为变异策略来控制粒子群算法,以避免现有灰色粒子群算法在求解多目标问题时所出现的局部收敛现象。通过四组不同类型的基准函数测试算法性能,测试结果表明该算法能很好地收敛到Pareto最优解集并有效避免了过早陷入局部最优解。     

Formulation and parameter selection of multi-objective deterministic particle swarm for simulation-based optimization

Global derivative-free deterministic algorithms are particularly suitable for simulation-based optimization, where often the existence of multiple local optima cannot be excluded a priori, the derivatives of the objective functions are not available, and the evaluation of the objectives is computationally expensive, thus a statistical analysis of the optimization outcomes is not practicable. Among these algorithms, particle swarm optimization (PSO) is advantageous for the ease of implementation and the capability of providing good approximate solutions to the optimization problem at a reasonable computational cost. PSO has been introduced for single-objective problems and several extension to multi-objective optimization are available in the literature. The objective of the present work is the systematic assessment and selection of the most promising formulation and setup parameters of multi-objective deterministic particle swarm optimization (MODPSO) for simulation-based problems. A comparative study of six formulations (varying the definition of cognitive and social attractors) and three setting parameters (number of particles, initialization method, and coefficient set) is performed using 66 analytical test problems. The number of objective functions range from two to three and the number of variables from two to eight, as often encountered in simulation-based engineering problems. The desired Pareto fronts are convex, concave, continuous, and discontinuous. A full-factorial combination of formulations and parameters is investigated, leading to more than 60,000 optimization runs, and assessed by three performance metrics. The most promising MODPSO formulation/parameter is identified and applied to the hull-form optimization of a high-speed catamaran in realistic ocean conditions. Its performance is finally compared with four stochastic algorithms, namely three versions of multi-objective PSO and the genetic algorithm NSGA-II.     

Real-time dynamic optimization of batch systems

In this paper a methodology for designing and implementing a real-time optimizing controller for batch processes is proposed. The controller is used to optimize a user-defined cost function subject to a parameterization of the input trajectories, a nominal model of the process and general state and input constraints. An interior point method with penalty function is used to incorporate constraints into a modified cost functional, and a Lyapunov based extremum seeking approach is used to compute the trajectory parameters. The technique is applicable to general nonlinear systems. A precise statement of the numerical implementation of the optimization routine is provided. It is shown how one can take into account the effect of sampling and discretization of the parameter update law in practical situations. A simulation example demonstrates the applicability of the technique.     

Multiobjective optimization of trusses using genetic algorithms

In this paper we propose the use of the genetic algorithm (GA) as a tool to solve multiobjective optimization problems in structures. Using the concept of min–max optimum, a new GA-based multiobjective optimization technique is proposed and two truss design problems are solved using it. The results produced by this new approach are compared to those produced by other mathematical programming techniques and GA-based approaches, proving that this technique generates better trade-offs and that the genetic algorithm can be used as a reliable numerical optimization tool.     

An integrated approach to topology,sizing, and shape optimization

Topology optimization has become very popular in industrial applications, and most FEM codes have implemented certain capabilities of topology optimization. However, most codes do not allow simultaneous treatment of sizing and shape optimization during the topology optimization phase. This poses a limitation on the design space and therefore prevents finding possible better designs since the interaction of sizing and shape variables with topology modification is excluded. In this paper, an integrated approach is developed to provide the user with the freedom of combining sizing, shape, and topology optimization in a single process.     

多元插值全局优化算法及其应用

本文介绍一种多元插值逼近和动态搜索轨迹相结合的全局优化算法.该算法大大减少了目标函数计算次数,寻优收敛速度快,算法稳定,且可获得全局极小,有效地解决了大规模非线性复杂动态系统的参数优化问题.一个具有8个控制参数的电力系统优化控制问题,采用该算法仅访问目标函数78次,便可求得最优控制器参数。     

Effects of dominant wolves in grey wolf optimization algorithm

Bio-inspired computation is one of the emerging soft computing techniques of the past decade. Although they do not guarantee optimality, the underlying reasons that make such algorithms become popular are indeed simplicity in implementation and being open to various improvements. Grey Wolf Optimizer (GWO), which derives inspiration from the hierarchical order and hunting behaviours of grey wolves in nature, is one of the new generation bio-inspired metaheuristics. GWO is first introduced to solve global optimization and mechanical design problems. Next, it has been applied to a variety of problems. As reported in numerous publications, GWO is shown to be a promising algorithm, however, the effects of characteristic mechanisms of GWO on solution quality has not been sufficiently discussed in the related literature. Accordingly, the present study analyses the effects of dominant wolves, which clearly have crucial effects on search capability of GWO and introduces new extensions, which are based on the variations of dominant wolves. In the first extension, three dominant wolves in GWO are evaluated first. Thus, an implicit local search without an additional computational cost is conducted at the beginning of each iteration. Only after repositioning of wolf council of higher-ranks, the rest of the pack is allowed to reposition. Secondarily, dominant wolves are exposed to learning curves so that the hierarchy amongst the leading wolves is established throughout generations. In the final modification, the procedures of the previous extensions are adopted simultaneously. The performances of all developed algorithms are tested on both constrained and unconstrained optimization problems including combinatorial problems such as uncapacitated facility location problem and 0-1 knapsack problem, which have numerous possible real-life applications. The proposed modifications are compared to the standard GWO, some other metaheuristic algorithms taken from the literature and Particle Swarm Optimization, which can be considered as a fundamental algorithm commonly employed in comparative studies. Finally, proposed algorithms are implemented on real-life cases of which the data are taken from the related publications. Statistically verified results point out significant improvements achieved by proposed modifications. In this regard, the results of the present study demonstrate that the dominant wolves have crucial effects on the performance of GWO.     

云搜索优化算法

本文将云的生成、动态运动、降雨和再生成等自然现象与智能优化算法的思想融合,建立了一种新的智能优化算法-云搜索优化算法(CSO)。生成与移动的云可以弥漫于整个搜索空间,这使得新算法具有较强的全局搜索能力;收缩与扩张的云团在形态上会有千奇百态的变化,这使得算法具有较强的局部搜索能力;降雨后产生新的云团可以保持云团的多样性,这也是使搜索避免陷入局优的有效手段。实验表明,基于这三点建立的新算法具有优异的性能,benchmark函数最优值的计算结果以及与已有智能优化算法的比较展现了新算法精确的、稳定的全局求解能力。     

Value Creation in a Network: The Role of Pricing and Revenue Optimization and Enterprise Profit OptimizationTM

The Internet has created a virtual upheaval in the structural features of the supply and demand chains for most businesses. New agents and marketplaces have surfaced. The potential to create value and enhance profitable opportunities has attracted both buyers and sellers to the Internet. Yet, the Internet has proven to be more complex than originally thought. With information comes complexity: the more the information in real time, the greater the difficulty in interpretation and absorption. How can the value-creating potential of the Internet still be realized, its complexity notwithstanding? This paper argues that with the emergence of innovative tools, the expectations of the Internet as a medium for enhanced profit opportunities can still be realized. Creating value on a continuing basis is central to sustaining profitable opportunities. This paper provides an overview of the value creation process in electronic networks, the emergence of the Internet as a viable business communication and collaboration medium, the proclamation by many that the future of the Internet resides in “embedded intelligence”, and the perspectives of pragmatists who point out the other facet of the Internet—its complexity. The paper then reviews some recent new tools that have emerged to address this complexity. In particular, the promise of Pricing and Revenue Optimization (PRO) and Enterprise Profit Optimization^TM (EPO) tools is discussed. The paper suggests that as buyers and sellers adopt EPO, the market will see the emergence of a truly intelligent network—a virtual network—of private and semi-public profitable communities.     

粒子群算法在组合优化问题上的研究与发展

粒子群优化算法是一种新兴的基于群智能搜索的优化技术。该算法简单、易实现、参数少,具有较强的全局优化能力,可有效应用于科学与工程实践中。介绍了算法的基本原理和算法在组合优化上一些改进方法的主要应用形式。最后,对粒子群算法作了一些深入分析并在此基础上对粒子群算法应用于组合优化问题做了一些总结。     

SEO技术研究

为了利用搜索引擎优化SEO（Search Engine Optimization）技术给网站带来高质量的流量并将其转化为商业利益,理解搜索引擎的算法和排名原理十分必要。通过对网站的结构优化、关键词优化、单页优化、防止被搜索引擎惩罚和挽救被惩罚网站等技术的研究,达到提高网站排名,实现网站的价值目的。