Self-adaptive mechanism based genetic algorithms for combinatorial optimization problems

To improve the evolutionary algorithm performance, especially in convergence speed and global optimization ability, a self-adaptive mechanism is designed both for the conventional genetic algorithm (CGA) and the quantum inspired genetic algorithm (QIGA). For the self-adaptive mechanism, each individual was assigned with suitable evolutionary parameter according to its current evolutionary state. Therefore, each individual can evolve toward to the currently best solution. Moreover, to reduce the running time of the proposed self-adaptive mechanism based QIGA (SAM-QIGA), a multi-universe parallel structure was employed in the paper. Simulation results show that the proposed SAM-QIGA have better performances both in convergence and global optimization ability.     

FPGA placement optimization by two-step unified Genetic Algorithm and Simulated Annealing algorithm

Genetic Algorithm （GA） is a biologically inspired technique and widely used to solve numerous combinational optimization problems. It works on a population of individuals, not just one single solution. As a result, it avoids converging to the local optimum. However, it takes too much CPU time in the late process of GA. On the other hand, in the late process Simulated Annealing （SA） converges faster than GA but it is easily trapped to local optimum. In this letter, a useful method that unifies GA and SA is introduced, which utilizes the advantage of the global search ability of GA and fast convergence of SA. The experimental results show that the proposed algorithm outperforms GA in terms of CPU time without degradation of performance. It also achieves highly comparable placement cost compared to the state-of-the-art results obtained by Versatile Place and Route （VPR） Tool.     

JOINT RANDOM OPTIMIZED THREE—STEP SEARCH ALGORITHM BASED—ON GRAY AND CHROMATIC INFORMATION

In this letter,an improved three-step search algorithm is presented,which uses both gray and chromatic information to boost the performance with random optimization and converge the motion vectors to global optima.Experimental results show that this algorithm can efficiently improve the PSNR after motion compensation.     

DOA and Power Estimation Using Genetic Algorithm and Fuzzy Discrete Particle Swarm Optimization

Aiming to reduce the computational costs and converge to global optimum, a novel method is proposed to solve the optimization of a cost function in the estimation of direction of arrival(DOA). In this method, a genetic algorithm(GA) and fuzzy discrete particle swarm optimization(FDPSO) are applied to optimize the direction of arrival and power parameters of the mode simultaneously. Firstly, the GA algorithm is applied to make the solution fall into the global searching. Secondly, the FDPSO method is utilized to narrow down the search field. In FDPSO, a chaotic factor and a crossover method are added to speed up the convergence. This approach has been demonstrated through some computational simulations. It is shown that the proposed algorithm can estimate both the DOA and the powers accurately. It is more efficient than some present methods, such as the Newton-like algorithm, Akaike information critical(AIC), particle swarm optimization(PSO), and genetic algorithm with particle swarm optimization(GA-PSO).     

Simulated annealing based polynomial time QoS routing algorithm for MANETs

Multi-constrained Quality-of-Service （QoS） routing is a big challenge for Mobile Ad hoc Networks （MANETs） where the topology may change constantly. In this paper a novel QoS Routing Algorithm based on Simulated Annealing （SA_RA） is proposed. This algorithm first uses an energy function to translate multiple QoS weights into a single mixed metric and then seeks to find a feasible path by simulated annealing. The paper outlines simulated annealing algorithm and analyzes the problems met when we apply it to Qos Routing （QoSR） in MANETs. Theoretical analysis and experiment results demonstrate that the proposed method is an effective approximation algorithms showing better performance than the other pertinent algorithm in seeking the （approximate） optimal configuration within a period of polynomial time.     

Dynamic computation offloading in time-varying environment forultra-dense networks: a stochastic game approach

To meet the demands of large-scale user access with computation-intensive and delay-sensitive applications, combining ultra-dense networks (UDNs) and mobile edge computing (MEC)are considered as important solutions. In the MEC enabled UDNs, one of the most important issues is computation offloading. Although a number of work have been done toward this issue, the problem of dynamic computation offloading in time-varying environment, especially the dynamic computation offloading problem for multi-user, has not been fully considered. Therefore, in order to fill this gap, the dynamic computation offloading problem in time-varying environment for multi-user is considered in this paper. By considering the dynamic changes of channel state and users queue state, the dynamic computation offloading problem for multi-user is formulated as a stochastic game, which aims to optimize the delay and packet loss rate of users. To find the optimal solution of the formulated optimization problem, Nash Q-learning (NQLN) algorithm is proposed which can be quickly converged to a Nash equilibrium solution. Finally, extensive simulation results are presented to demonstrate the superiority of NQLN algorithm. It is shown that NQLN algorithm has better optimization performance than the benchmark schemes.     

Algorithm for the detection and parameter estimation of multicomponent LFM signals

A novel algorithm based on Radon-Ambiguity Transform (RAT) and Adaptive Signal Decomposition (ASD) is presented for the detection and parameter estimation of multicomponent Linear Frequency Modulated (LFM) signals. The key problem lies in the chirplet estimation.Genetic algorithm is employed to search for the optimization parameter of chirplet. High estimation accuracy can be obtained even at low Signal-to-Noise Ratio(SNR). Finally simulation results are provided to demonstrate the performance of the proposed algorithm.     

Hybrid gray wolf optimization-cuckoo search algorithm for RFID network planning

In recent years, with the rapid development of Internet of things (IoT) technology, radio frequency identification (RFID) technology as the core of IoT technology has been paid more and more attention, and RFID network planning(RNP) has become the primary concern. Compared with the traditional methods, meta-heuristic method is widely used in RNP. Aiming at the target requirements of RFID, such as fewer readers, covering more tags, reducing the interference between readers and saving costs, this paper proposes a hybrid gray wolf optimization-cuckoo search (GWO-CS) algorithm. This method uses the input representation based on random gray wolf search and evaluates the tag density and location to determine the combination performance of the reader's propagation area. Compared with particle swarm optimization ( PSO) algorithm, cuckoo search( CS) algorithm and gray wolf optimization ( GWO) algorithm under the same experimental conditions, the coverage of GWO-CS is 9.306% higher than that of PSO algorithm, 6.963% higher than that of CS algorithm, and 3.488% higher than that of GWO algorithm. The results show that the GWO-CS algorithm cannot only improve the global search range, but also improve the local search depth.     

Moving object extraction based on saliency detection and adaptive background model

For the ghost in visual background extractor(Vi Be)algorithm and the influence of dynamic background,an improved Vi Be algorithm is proposed to extract moving object in this paper.The way of background acquisition during modeling is improved to eliminate the ghost.Detect the saliency of the pre-M-frame,and synthetic relatively real background.Modeling with the background can avoid the generation of ghost.The selection of thresholds in the model is improved to reduce the impact of the dynamic background.Adjust the thresholds adaptively according to the background complexity.In addition,find the inner contour of extracted object to fill,which makes the detected targets more complete.Experimental results show that the presented algorithm effectively removes ghosts and enhances anti-interference ability.Compared with several existing methods,the presented algorithm has better performance.     

求解约束优化问题的混合粒子群算法

针对约束优化问题提出一种混合粒子群求解算法,该算法根据可行性规则,引入自适应惩罚函数,结合模拟退火算法,不断地寻找更优可行解,逐渐达到搜索全局最优解.通过对一些标准函数测试,计算机仿真结果表明,该方法是有效和可行的,且具有较高的计算精度,相比传统算法,最优解精度达到10-15.     

最大期望模拟退火的贝叶斯变分推理算法

针对贝叶斯变分推理收敛精度低和搜索过程中易陷入局部最优的问题，该文基于模拟退火理论(SA)和最大期望理论(EM)，考虑变分推理过程中初始先验对最终结果的影响和变分自由能的优化效率问题，构建了双重EM模型学习变分参数的初始先验，以降低初始先验的敏感性，同时构建逆温度参数改进变分自由能函数，使变分自由能在优化过程得到有效控制，并提出一种基于最大期望模拟退火的贝叶斯变分推理算法。该文使用收敛性准则理论分析算法的收敛性，利用所提算法对一个混合高斯分布实例进行实验仿真，实验结果表明该算法具有较优的收敛结果。     

改进模拟退火算法在矢量量化编码中的应用

为了提高模拟退火算法的最终解的质量,文中对控制算法进程的冷却进度表进行了优化选取,尤其在控制马尔可夫链长方面,给出了依据算法搜索过程的反馈信息来控制马尔可夫链长的方法.将该算法与LBG算法相结合,应用于矢量量化图像编码,既保持了模拟退火对初始码书依赖性小、不容易陷入局部极值的优点,又具备LBG算法的易于实现和计算量小的特点.仿真实验表明,该算法提高了码书的编码性能.     

基于混合优化算法的正交多相码的设计

通过结合模拟退火算法的概率接受准则和蚁群算法的并行搜索，提出了一种有效的混合优化算法，设计出了具有良好自相关和互相关性能的正交信号组。混合算法弥补了模拟退火算法的搜索效率低和蚁群算法的容易陷入局部最小值的缺点，提高了全局搜索的能力。仿真结果表明，在搜索最优正交多相码方面该混合优化算法优于其他搜索算法。     

基于生态种群捕获竞争模型的多目标Memetic优化算法

本文针对复杂多目标优化问题Pareto前沿搜索难度大的特点,设计了一种结合多种群间捕获竞争、强化学习机制的多种群Memetic学习策略与进化计算模型.受种群进化、捕食种群与被捕食群体间的竞争等生态学原理的启发,提出了一种基于生态种群捕获竞争模型的多目标Memetic优化算法(Multi-Objective Memetic Algorithm based on Ecological Population Preying-competition Model,ECPM-MOMA).ECPM-MOMA算法设计并运用了捕获竞争、强化学习算子进行全局搜索,在种群进化过程中结合了Memetic搜索算子进行局部搜索.理论分析与实验结果表明,本文所提出的算法具有良好的收敛性能和分布特征,生态种群捕获竞争策略与进化计算模型对于解决复杂多目标优化问题是有效的.     

Parametric Yield Optimization of MOS IC's Affected by Device Mismatch

In this paper a statistical design procedure for the parametric yield optimization based on Simulated Annealing and Quasi-Newton algorithms is presented. A rigorous formulation of the yield taking into account both inter-die and intra-die (mismatch) device variations has been used in defining the procedure steps. A reduction in the complexity of the yield optimization algorithm is achieved by performing a screening of the parameters, discarding those having small effect on the required performance. Application examples evidence the achievement of the method.     

面向软模块的稳定固定边框布图规划算法

该文提出一种稳定的面向软模块的固定边框布图规划算法。该算法基于正则波兰表达式(Normalized Polish Expression, NPE)表示,提出一种基于形状曲线相加和插值技术的计算NPE最优布图的方法,并运用模拟退火(Simulation Annealing, SA)算法搜索最优解。为了求得满足固定边框的布图解,提出一种基于删除后插入(Insertion After Delete, IAD)算子的后布图优化方法。对8个GSRC和MCNC电路的实验结果表明,所提出算法在1%空白面积率的边框约束下的布图成功率接近100%,在总线长上较已有文献有较大改进,且在求解速度上较同类基于SA的算法有较大优势。     

一种基于边缘分布估计的多目标优化算法

该文提出了一种基于边缘分布估计的多目标优化算法,通过在每一进化代中估计较优个体的边缘概率分布来引导算法对Pareto最优解的搜索。通过与基于拥挤机制的多样性保持技术、基于非支配排序的联赛选择、精英保留等技术的有机结合,使得算法在具有良好收敛性能的同时,具有很好的维持群体多样性的能力。通过一组典型测试函数实验对该算法的性能进行了分析,并与NSGA-II、SPEA、PAES等知名多目标优化算法进行了比较,结果表明该文算法收敛速度较快,且得到的非支配解集分布均匀,适合于复杂多目标优化问题的求解。     

混合精英策略的元胞多目标遗传算法及其应用

为了提高Pareto解集的收敛性,平衡多目标优化的全局搜索和局部寻优的能力,提出一种混合精英策略的元胞多目标遗传算法。该算法在分析元胞种群结构的特点基础上,融入一种混合精英策略,提高算法的收敛性能。为了更好的平衡算法的全局搜索和局部寻优的能力,加入一种差分进化交叉算子。通过与同类算法在21个基准函数上对比实验,结果表明,引入混合精英策略和差分进化策略能够提高算法的性能,与其他优秀算法进行比较的结果说明,新算法有更好的收敛性和多样性。工程实例求解结果表明了算法的工程可行性。     

用蚁群优化算法求解中国旅行商问题

中国旅行商问题是一个组合优化问题，是一个NP问题。本文提出用蚁群优化算法去解决，同时提出了两种改进的方法，其中，Ant-F能够增强系统的搜索能力，使系统避免早熟，具有正负反馈的功能，仿真简单，容易理解；而ACS 在Ant Colony System(ACS)的基础上改进而成，它使系统在演化的后期能够通过适当增大系统区分信息素对比强度的方法，尽快找到最优的解。和其它的几种蚁群优化算法、遗传算法和模拟退火算法相比较，实验表明，ACS 是本文提及的几种算法中最优的一种，它能加快系统收敛的速度，找到问题的最优值。