改进万有引力搜索算法及在水位辨识中的应用

针对万有引力搜索算法(Gravitational Search Algorithm,GSA)的早熟收敛和寻优精度问题,提出了一种改进的GSA算法。算法采用混沌序列初始化种群位置,采用淘汰机制及变异操作增加种群的多样性,避免陷入局部最优。通过对6个非线性基准函数进行仿真测试,结果表明:所提出的算法对非线性函数具有良好的优化性能。将上述算法用于双容水箱水位的辨识,辨识结果验证了提出算法的有效性。     

引力搜索算法的改进

引力搜索算法GSA(Gravitationa lSearch Algorithm)是最近由Esmat Rashedi基于引力定律提出的一个新算法。在引力搜索算法的基础上对其进行改进,得到了基于权值的引力搜索算法。与引力搜索算法相比,该算法在每一次迭代的过程中,都对粒子的惯性质量加一个权值。用算法对许多基准函数测试的实验效果表明,该方法可以使得引力搜索算法得到更好的结果。     

基于旋转学习策略的共生生物搜索算法

为提高共生生物搜索算法(Symbiotic Organisms Search, SOS)的性能,提出一种基于旋转学习策略的共生生物搜索算法(Symbiotic Organisms Search Using Rotation-Based Learning, RSOS)。该算法将串行个体更新方式改为并行种群更新方式,提高算法收敛速度;引入遍历保优的旋转学习策略,代替寄生机制的盲目随机搜索,增大保留新个体的概率,补充种群多样性,提高算法跳出局部最优的能力。对于8个标准测试函数仿真表明,RSOS算法较基本SOS算法在收敛速度、收敛精度及稳定性上得到了明显提升。     

引力搜索算法在多阈值图像分割中的应用研究

针对求解高维阈值图像分割计算复杂的问题,提出了一种基于引力搜索算法的多阈值图像分割方法,该方法以大津法（Otsu）设计为适应度函数,利用引力搜索算法快速搜索得到待分割图像的最优阈值,然后根据最优阈值进行图像分割。结合人眼视觉可知,引力搜索算法能够结合应用于图像分割,且能取得较好的效果。实验测试结果表明,该方法与布谷鸟算法、人工蜂群算法比较,引力搜索算法的收敛速度更快,寻优的阈值质量较高。     

大规模MIMO系统中优化导频分配方案研究

针对大规模MIMO系统中小区间干扰而导致的导频污染问题,提出了基于IGTSA（Improved Greedy and Tabu Search Algorithm,改进贪婪禁忌搜索算法）和基于CA（Competition Algorithm,竞争算法）的导频分配方案。提出的ITSA是将遗传算法中的变异操作加入禁忌算法来避免其陷入局部最优解,提升全局搜索能力。为更好地实现全局搜索与局部搜索的协调统一,引入CA进一步优化以系统可达和速率达到最大为目标的导频分配方案。相比于局部搜索算法,如GA（Greedy Algorithm,贪婪算法）和TSA（Tabu Search Algorithm,禁忌搜索算法）,所提出的方案能获得更优的系统性能。仿真结果和分析证明了算法的有效性。     

爆炸搜索算法及其收敛性证明

受烟花(炸弹)爆炸的启发,结合经典优化算法提出了一种新的智能优化算法—爆炸搜索算法(Explosion Search Algorithm, ESA) 。ESA引入部域搜索的思想,将智能优化算法与下降搜索算法进行有机结合,使得ESA具有强大的局部搜索能力和全局搜索能力以及好的收敛精度。对算法的收敛性进行了证明,最后通过对benchmark函数集进行仿真并同其他算法进行比较,验证了ESA的高效性。     

基于改进引力搜索的混合K-调和均值聚类算法研究

为了解决聚类算法容易陷入局部最优的问题,以及增强聚类算法的全局搜索能力,基于KHM算法以及改进的引力搜索算法,本文提出一种混合K-调和均值聚类算法（G-KHM）。G-KHM算法具有KHM算法收敛速度快的优点,但同时针对KHM算法容易陷入局部最优解的问题,在初始化后数据开始搜索聚类中心时采用了一种基于对象多样性及收敛性增强的引力搜索算法,该方法改进了引力搜索算法容易失去种群多样性的缺点,并同时具有引力搜索算法较强的全局搜索能力,可以使算法收敛到全局最优解。仿真结果表明,G-KHM算法能有效地避免陷入局部极值,具有较强的全局搜索能力以及稳定性,并且相比KHM算法、K-mean聚类算法、C均值聚类算法以及粒子群算法,在分类精度和运行时间上表现出了更好地效果。     

开放式车辆路径问题的混合算法

为研究开放式车辆路径问题(Open Vehicle Routing Problem,OVRP),建立了数学模型.针对遗传算法(Genetic Algorithm,GA)与禁忌搜索算法(Tabu Search Algorithm,TSA)的不足,提出了一个采用GA和TSA相结合的混合算法求解OVRP.混合算法中以GA为主,把TSA用在GA的变异操作中,增强算法的爬山能力.通过仿真,将提出的混合算法与文献中其它算法比较,结果表明它可以快速、有效求得最优解或近似解.     

协同混合粒子群算法求解车间作业调度问题

针对如何有效解决车间作业优化调度问题,提出一种协同粒子群和引力搜索的混合算法。新算法在粒子群算法进化停滞时引入引力搜索算法,利用引力搜索算法进化后期快速寻优的能力,及时跳出局部最优,保证全局最优。同时采用协同原理简化算法结构,提高算法收敛速度。将提出算法对车间作业调度典型测试用例进行仿真,仿真结果表明该算法较PSO和GA等算法在求解车间作业调度问题上更具优越性。     

基于改进引力搜索算法的桁架结构优化设计

引力搜索算法是近几年提出的较有竞争力的群智能优化算法,然而,标准引力搜索算法存在后期收敛速度慢的缺点。为有效利用优化算法来解决结构优化的问题,提出一种改进的引力搜索算法(improved gravitational search algorithm,IGSA)。通过引入Logistic映射,使GSA初始种群遍历整个搜索空间,提高算法找出最优解的可能性。通过引入粒子群算法(particle swarm optimization,PSO)的信息交互机制,利用个体粒子历史最佳位置和种群历史最佳位置动态调整粒子的速度和位置,使个体粒子更快地向适应度值更高的位置移动,使算法搜索能力加强。对6个经典测试函数进行寻优,结果表明改进后算法收敛速度快,收敛精度高,稳定性较佳,跳出局部最佳解的能力较强。用IGSA和GSA对72杆空间桁架进行尺寸优化,与其他算法相比,结果表明IGSA得到最优值的迭代次数明显减少,得到的最优解明显优于通用算法。     

A Multi-Layered Gravitational Search Algorithm for Function Optimization and Real-World Problems

A gravitational search algorithm(GSA)uses gravitational force among individuals to evolve population.Though GSA is an effective population-based algorithm,it exhibits low search performance and premature convergence.To ameliorate these issues,this work proposes a multi-layered GSA called MLGSA.Inspired by the two-layered structure of GSA,four layers consisting of population,iteration-best,personal-best and global-best layers are constructed.Hierarchical interactions among four layers are dynamically implemented in different search stages to greatly improve both exploration and exploitation abilities of population.Performance comparison between MLGSA and nine existing GSA variants on twenty-nine CEC2017 test functions with low,medium and high dimensions demonstrates that MLGSA is the most competitive one.It is also compared with four particle swarm optimization variants to verify its excellent performance.Moreover,the analysis of hierarchical interactions is discussed to illustrate the influence of a complete hierarchy on its performance.The relationship between its population diversity and fitness diversity is analyzed to clarify its search performance.Its computational complexity is given to show its efficiency.Finally,it is applied to twenty-two CEC2011 real-world optimization problems to show its practicality.     

带有Levy Flight机制的引力搜索算法

引力搜索算法（gravitational search algorithm,GSA）是模拟万有引力定律进行搜索的一种新颖的优化算法,已有研究表明GSA算法相比一些传统的优化算法拥有较好的收敛性能,但其缺乏有效的全局寻优机制,易于被局部极值吸引,从而陷入早熟收敛。因此提出了一种基于Levy Flight和权值惯性递减的引力搜索算法QmuGSA,以加强算法的全局寻优能力。该算法通过Levy Flight独特的不均匀随机游走的机制扩大粒子的搜索范围,增加种群多样性,从而更容易跳出局部最优点。通过4个标准测试函数对所提算法进行了仿真测试,结果表明所提算法能够有效克服基本引力搜索算法易早熟、收敛精度低等缺陷,具有较好的寻优精度和全局收敛性能,能够解决一些复杂函数的优化问题。     

An improved gravitational search algorithm for dynamic neural network identification

Gravitational search algorithm (GSA) is a newly developed and promising algorithm based on the law of gravity and interaction between masses. This paper proposes an improved gravitational search algorithm (IGSA) to improve the performance of the GSA, and first applies it to the field of dynamic neural network identification. The IGSA uses trial-and-error method to update the optimal agent during the whole search process. And in the late period of the search, it changes the orbit of the poor agent and searches the optimal agent’s position further using the coordinate descent method. For the experimental verification of the proposed algorithm, both GSA and IGSA are testified on a suite of four well-known benchmark functions and their complexities are compared. It is shown that IGSA has much better efficiency, optimization precision, convergence rate and robustness than GSA. Thereafter, the IGSA is applied to the nonlinear autoregressive exogenous (NARX) recurrent neural network identification for a magnetic levitation system. Compared with the system identification based on gravitational search algorithm neural network (GSANN) and other conventional methods like BPNN and GANN, the proposed algorithm shows the best performance.     

A novel hybrid algorithm of gravitational search algorithm with genetic algorithm for multi-level thresholding

The multi-level thresholding is a popular method for image segmentation. However, the method is computationally expensive and suffers from premature convergence when level increases. To solve the two problems, this paper presents an advanced version of gravitational search algorithm (GSA), namely hybrid algorithm of GSA with genetic algorithm (GA) (GSA-GA) for multi-level thresholding. In GSA-GA, when premature convergence occurred, the roulette selection and discrete mutation operators of GA are introduced to diversify the population and escape from premature convergence. The introduction of these operators therefore promotes GSA-GA to perform faster and more accurate multi-level image thresholding. In this paper, two common criteria (1) entropy and (2) between-class variance were utilized as fitness functions. Experiments have been performed on six test images using various numbers of thresholds. The experimental results were compared with standard GSA and three state-of-art GSA variants. Comparison results showed that the GSA-GA produced superior or comparative segmentation accuracy in both entropy and between-class variance criteria. Moreover, the statistical significance test demonstrated that GSA-GA significantly reduce the computational complexity for all of the tested images.     

基于改进的Tent混沌万有引力搜索算法

万有引力搜索算法(gravitational search algorithm,GSA)相比于传统的优化算法具有收敛速度快、开拓性能强等特点,但GSA易陷入早熟收敛和局部最优,搜索能力较弱.为此,提出一种基于改进的Tent混沌万有引力搜索算法(gravitational search algorithm based on improved tent chaos,ITC-GSA).首先,改进Tent混沌映射来初始化种群,利用Tent混沌序列随机性、遍历性和规律性的特性使得初始种群随机性和遍历性在可行域内,具有加强算法的全局搜索能力;其次,引入引力常数G的动态调整策略提高算法的收敛速度和收敛精度;再次,设计成熟度指标判断种群成熟度,并使用Tent混沌搜索有效抑制算法早熟收敛,帮助种群跳出局部最优;最后,对10个基准函数进行仿真实验,结果表明所提算法能够有效克服GSA易陷入早熟收敛和局部最优的缺点,提高算法的收敛速度和寻优精度.     

A memory-based gravitational search algorithm for enhancing minimum variance distortionless response beamforming

This paper introduces a memory-based version of gravitational search algorithm (MBGSA) to improve the beamforming performance by preventing loss of optimal trajectory. The conventional gravitational search algorithm (GSA) is a memory-less heuristic optimization algorithm based on Newton’s laws of gravitation. Therefore, the positions of agents only depend on the optimal solutions of previous iteration. In GSA, there is always a chance to lose optimal trajectory because of not utilizing the best solution from previous iterations of the optimization process. This drawback reduces the performance of GSA when dealing with complicated optimization problems. However, the MBGSA uses the overall best solution of the agents from previous iterations in the calculation of agents’ positions. Consequently, the agents try to improve their positions by always searching around overall best solutions. The performance of the MBGSA is evaluated by solving fourteen standard benchmark optimization problems and the results are compared with GSA and modified GSA (MGSA). It is also applied to adaptive beamforming problems to improve the weight vectors computed by Minimum Variance Distortionless Response (MVDR) algorithm as a real world optimization problem. The proposed algorithm demonstrates high performance of convergence compared to GSA and Particle Swarm Optimization (PSO).     

Research on a new optimization algorithm simulating multi- states of matter inspired by finite element analysis approach

A new optimization algorithm is proposed, since a huge problem that many algorithms faced was not being able to effectively balance the global and local search ability. Matter exists in three states: solid, liquid, and gas, which presents different motion characteristics. Inspired by multi- states of matter, individuals of optimization algorithm have different motion characteristics of matter, which could present different search ability. The Finite Element Analysis (FEA) approach can simulate multi- states of matter, which can be adopted to effectively balance the global search ability and local search ability in new optimization algorithm. The new algorithm is creative application of Finite Element Analysis at optimization algorithm field. Artificial Physics Optimization (APO) and Gravitational Search Algorithm (GSA) belongs to the algorithm types defined by force and mass. According to FEA approach, node displacement caused by force and stiffness could be equivalent to motion caused by force and mass of APO and GSA. In the new algorithm framework, stiffness replaces mass of APO and GSA algorithm. This paper performs research on two different algorithms based on APO and GSA respectively. The individuals of new optimization algorithm are divided into solid state, liquid state, and gas state. The effects of main parameters on the performance were studied through experiments of 6 static test functions. The performance is compared with PSO, basic APO, or GSA for four complex models which made up of solid individual, liquid individual, and gas individual in iterative process. The reasonable complex model can be confirmed experimentally. Based on the reasonable complex model, the article conducted complete experiments against Enhancing artificial bee colony algorithm with multi-elite guidance (MGABC), Artificial bee colony algorithm with an adaptive greedy position update strategy (AABC), Multi-strategy ensemble artificial bee colony (MEABC), Self-adaptive heterogeneous PSO (fk-PSO), and APO with 28 CEC2013 test problem. Experimental results show that the proposed method achieves a good performance in comparison to its counterparts as a consequence of its better exploration– exploitation balance. The algorithm supplies a new method to improve physics optimization algorithm.

     

多策略融合的改进万有引力搜索算法

为解决传统万有引力搜索算法（GSA）易陷入局部最优和开发能力弱等问题,提出了一种多策略融合的改进万有引力搜索算法（MFGSA）。首先,提出动态调整引力常数G的更新策略,以增强算法的探索能力和收敛精度;其次,为保留粒子的多样性,提出了基于对称思想的粒子越界处理策略,以提高算法的收敛精度;为适应前两个策略,还引入精英思想,用最优粒子改善最差粒子位置策略,以避免算法陷入局部最优;同时,提出了自适应因子更新粒子速度和位置策略,以提高算法的收敛速度。为验证改进算法的性能,将改进算法与传统万有引力搜索算法和其他四种改进万有引力搜索算法在10个基准函数上进行了对比实验,结果表明MFGSA在收敛速度、搜索精度方面优势较大,表明MFGSA性能的优越性。     

Binary optimization using hybrid particle swarm optimization and gravitational search algorithm

The PSOGSA is a novel hybrid optimization algorithm, combining strengths of both particle swarm optimization (PSO) and gravitational search algorithm (GSA). It has been proven that this algorithm outperforms both PSO and GSA in terms of improved exploration and exploitation. The original version of this algorithm is well suited for problems with continuous search space. Some problems, however, have binary parameters. This paper proposes a binary version of hybrid PSOGSA called BPSOGSA to solve these kinds of optimization problems. The paper also considers integration of adaptive values to further balance exploration and exploitation of BPSOGSA. In order to evaluate the efficiencies of the proposed binary algorithm, 22 benchmark functions are employed and divided into three groups: unimodal, multimodal, and composite. The experimental results confirm better performance of BPSOGSA compared with binary gravitational search algorithm (BGSA), binary particle swarm optimization (BPSO), and genetic algorithm in terms of avoiding local minima and convergence rate.