Filter modeling using gravitational search algorithm

This paper is devoted to the presentation of a new linear and nonlinear filter modeling based on a gravitational search algorithm (GSA). To do this, unknown filter parameters are considered as a vector to be optimized. Examples of infinite impulse response (IIR) filter design, as well as rational nonlinear filter, are given. To verify the effectiveness of the proposed GSA based filter modeling, different sets of initial population with the presence of different measurable noises are given and tested in simulations. Genetic algorithm (GA) and particle swarm optimization (PSO) are also used to model the same examples and some simulation results are compared. Obtained results confirm the efficiency of the proposed method.     

Improving a model for the dynamic modulus of asphalt using the modified harmony search algorithm

We report the improvement of a dynamic modulus model using a modified harmony search (MHS) algorithm to describe the resistance to rutting and fatigue cracking of asphalt concrete mixtures. The MHS algorithm was reformulated to improve the harmony search (HS) algorithm by introducing minimum and maximum bandwidths. Using the MHS algorithm, model parameters for lime-modified asphalt concrete mixtures were extracted and a good fit to the dynamic modulus data obtained from laboratory tests was achieved.     

云模型的布谷鸟搜索算法*

针对布谷鸟搜索算法(CS)存在的不足,优化布谷鸟搜索算法求解连续函数问题的性能,结合云模型在定性与定量之间相互转换的优良特性,设计出云模型的布谷鸟搜索算法(CCS)。其核心思想是通过云模型实现布谷鸟的进化学习过程,类似差分进化进行群体间的信息交流。经过10个测试函数的实验仿真,测试结果表明该文算法能有效改善求解连续函数优化问题的性能。同时,针对连续函数优化问题,该算法与其它算法相比是有更好性能的优化算法。     

采用多模式飞行的乌鸦搜索算法

针对乌鸦搜索算法（CSA）的不足,提出采用多模式飞行的乌鸦搜索算法（MFCSA）。算法基于觅食能力的强弱,将群体分成觅食能力较强和较弱两个组,觅食能力较强者采用尾随跟踪当前群体最优目标策略,在群体信息指引下飞到群体当前最优位置附近开展搜索活动,增强了算法的局部开发能力; 觅食能力较弱者采用观察和学习强者的觅食方法、遇到危险迅速飞离两种策略,前者可提升算法的全局探索能力,后者可保持种群的多样性。通过15个基准测试函数和两个工程应用问题的数值实验仿真结果表明,MFCSA在优化精度、收敛速度等方面有更好的表现,增强了规避陷入局部最优的能力,稳定性更好。     

一种引入Nelder-Mead算子的改进狼群搜索算法*

为了克服狼群搜索算法(WSA)存在的不足,提出一种新的混合优化算法,称之为引入Nelder-Mead算子的改进狼群搜索算法。该算法使每只狼在搜索中可利用群体信息和个体记忆来指导其搜索猎物,以提高算法的全局搜索能力;让每只狼在搜索中可使用Nelder-Mead方法,以弥补WSA算法在局部搜索能力上的不足。针对12个基准测试实例的实验结果表明, 该算法能够寻得更优的最优解,且鲁棒性更强。     

Parameter optimization of distributed hydrological model with a modified dynamically dimensioned search algorithm

A modified version of the dynamically dimensioned search (MDDS) is introduced for automatic calibration of watershed simulation models. The distinguishing feature of the MDDS is that the algorithm makes full use of sensitivity information in the optimization procedure. The Latin hypercube one-factor-at-a-time (LH-OAT) technique is used to calculate the sensitivity information of every parameter in the model. The performance of the MDDS is compared to that of the dynamically dimensioned search (DDS), the DDS identifying only the most sensitive parameters, and the shuffled complex evolution (SCE) method, respectively, for calibration of the easy distributed hydrological model (EasyDHM). The comparisons range from 500 to 5000 model evaluations per optimization trial. The results show the following: the MDDS algorithm outperforms the DDS algorithm, the DDS algorithm identifying the most sensitive parameters, and the SCE algorithm within a specified maximum number of function evaluations (fewer than 5000); the MDDS algorithm shows robustness compared with the DDS algorithm when the maximum number of model evaluations is less than 2500; the advantages of the MDDS algorithm are more obvious for a high-dimensional distributed hydrological model, such as the EasyDHM model; and the optimization results from the MDDS algorithm are not very sensitive to either the variance (between 0.3 and 1) for randn′ used in the MDDS algorithm or the number of strata used in the Latin hypercube (LH) sampling.     

基于遗传算法和禁忌搜索的混合优化策略

将禁忌搜索和遗传算法相结合,给出了一种求解优化问题的混合策略--禁忌遗传优化算法.该算法一方面为禁忌搜索找到了较好的初始点,减少了调用禁忌搜索的次数,另一方面也可以克服遗传算法爬山能力差的缺点,从而加快了收敛速度,提高了解的质量.通过实例验证了该优化算法的有效性和可靠性,并将其用于网络拥塞控制的研究中,为进一步实施网络拥塞控制提供了一种有效的途径.     

Eigenvalue assignments in multimachine power systems using tabu search algorithm

Applying tabu search (TS) optimization technique to multimachine power system stabilizer (PSS) design is presented in this paper. The proposed approach employs TS to search for optimal or near optimal settings of PSS parameters that shift the system eigenvalues associated with the electromechanical modes to the left of a vertical line in the s-plane. Incorporation of TS algorithm in PSS design significantly reduces the computational burden. One of the main advantages of the proposed approach is its robustness to the initial guess. The performance of the proposed PSS under different disturbances and loading conditions is investigated for multimachine power systems. The eigenvalue analysis and the nonlinear simulation results show the effectiveness of the proposed PSSs to damp out the local as well as the interarea modes of oscillations and work effectively over a wide range of loading conditions and system configurations.     

动态优化问题的瞬态自适应麻雀搜索算法求解

动态优化普遍存在于工业过程控制领域,是实现系统稳态与产值最大化的重要手段,应用并发展更加高效的动态优化方法逐渐成为了当前研究的热点。鉴于此,提出一种基于瞬态自适应麻雀搜索算法（TASSA）的动态优化问题求解方案。首先,分析了原始麻雀搜索算法的缺陷,为了提升全局勘探能力,引入瞬态搜索策略指导加入者的寻优过程;其次,采用随迭代而变化的惯性权重调节具体的搜索方式,增强了算法的动态适应能力,并通过九组基准函数的数值测试确认了改进策略的有效性。最后,采用时域等分的方式,在控制变量参数化（CVP）的框架下利用TASSA对三组典型的动态优化问题进行求解,对比不同文献中的方法,所提算法取得了更精确的结果。     

Medical image reconstruction using a multi-objective genetic local search algorithm

Image reconstruction from projections is a key problem in medical image analysis. In this paper, we cast image reconstruction from projections as a multi-objective problem. It is essential to choose some proper objective functions of the problem. We choose the square error, smoothness of the reconstructed image, and the maximum entropy as our objective functions of the problem. Then we introduce a hybrid algorithm comprising of multi-objective genetic and local search algorithms to reconstruct the image. Our algorithm has remarkable global performance. Our experiments show that we can get different results when we give different weights to different objective functions. We can also control the noise by giving different weights on different objective function. At the same time, we can adjust the parameter to let it have good local performance. Though the computation demands of the hybrid algorithm tends to be larger because of the random search of the GA, it is really a common feature of the global optimization method. Our results show that the hybrid algorithm is a more effective than the conventional method. We think our method is very promising for the medical imaging field.     

基于集成模型与遍历搜索算法的铅锌烧结透气性优化

以铅锌烧结过程为研究对象,针对烧结过程透气性的控制问题,提出了基于集成预测模型与遍历优化搜索算法的铅锌烧结透气性优化控制方法.首先采用优化组合集成技术将神经网络预测模型和灰色系统预测模型有机结合,建立烧结综合透气性集成预测模型,然后结合14# 风箱温度和烧穿点温度建立透气性状况综合评判模型,最后通过遍历优化搜索算法,获得二配配比和混合料水分设定值,并进行跟踪控制,从而实现烧结过程透气性的优化控制.仿真结果表明:该方法能有效改善烧结过程的透气性.稳定烧结过程.     

A fuzzy curved search algorithm for neural network learning

In this paper, we develop a curved search algorithm which uses second-order information, for the learning algorithm for a supervised neural network. With the objective of reducing the training time, we introduce a fuzzy controller for adjusting the first and second-order approximation parameters in the iterative method to further reduce the training time and to avoid the spikes in the learning curve which sometimes occurred with the fixed step length. Computational results indicate a significant reduction in training when comparing with the delta learning rule.     

布谷鸟搜索算法优化BP神经网络的网络流量预测

为了提高预测精度,提出一种布谷鸟搜索算法优化BP神经网络的网络流量预测模型(Cuckoo Search BP neural network Flow Prediction,CS-BPNN)。根据混沌理论建立网络流量学习样本,采用BP神经网络对学习样本进行训练,将模型参数当一个鸟巢,通过模拟布谷鸟寻窝产卵的行为找到最优模型参数,最后采用网络流量数据进行仿真实验,测试模型性能。仿真实验表明:所提出模型较好的解决了BP神经参数优化问题,能够获得更加理想的网络流量预测结果。     

Harmony filter: A robust visual tracking system using the improved harmony search algorithm

In this article a novel approach to visual tracking called the harmony filter is presented. It is based on the Harmony Search algorithm, a derivative free meta-heuristic optimisation algorithm inspired by the way musicians improvise new harmonies. The harmony filter models the target as a colour histogram and searches for the best estimated target location using the Bhattacharyya coefficient as a fitness metric. Experimental results show that the harmony filter can robustly track an arbitrary target in challenging conditions. We compare the speed and accuracy of the harmony filter with other popular tracking algorithms including the particle filter and the unscented Kalman filter. Experimental results show the harmony filter to be faster and more accurate than both the particle filter and the unscented Kalman filter.     

自适应微调扰动和声搜索算法几何约束求解研究*

几何约束求解的方法关系到特征造型系统的性能,为提高几何约束求解的速度,将和声搜索算法应用于几何约束求解中。通过优先选择较小的和声库,利用最好解的评价值确定微调扰动的幅度,并将其嵌入到拉斯维加斯算法中,提高了和声搜索算法的性能。实验结果表明,改进的和声算法具有自适应性,能有效克服局部收敛问题,提高了求解速度。     

Chaotic gravitational constants for the gravitational search algorithm

In a population-based meta-heuristic, the search process is divided into two main phases: exploration versus exploitation. In the exploration phase, a random behavior is fruitful to explore the search space as extensive as possible. In contrast, a fast exploitation toward the promising regions is the main objective of the latter phase. It is really challenging to find a proper balance between these two phases because of the stochastic nature of population-based meta-heuristic algorithms. The literature shows that chaotic maps are able to improve both phases. This work embeds ten chaotic maps into the gravitational constant (G) of the recently proposed population-based meta-heuristic algorithm called Gravitational Search Algorithm (GSA). Also, an adaptive normalization method is proposed to transit from the exploration phase to the exploitation phase smoothly. As case studies, twelve shifted and biased benchmark functions evaluate the performance of the proposed chaos-based GSA algorithms in terms of exploration and exploitation. A statistical test called Wilcoxon rank-sum is done to judge about the significance of the results as well. The results demonstrate that sinusoidal map is the best map for improving the performance of GSA significantly.     

Improved non-maximum suppression for object detection using harmony search algorithm

Non-maximum suppression (NMS) plays a key role in many modern object detectors. It is responsible to remove detection boxes that cover the same object. NMS greedily selects the detection box with maximum score; other detection boxes are suppressed when the degree of overlap between these detection boxes and the selected box exceeds a predefined threshold. Such a strategy easily retain some false positives, and it limits the ability of NMS to perceive nearby objects in cluttered scenes. This paper proposes an effective method combining harmony search algorithm and NMS to alleviate this problem. This method regards the task of NMS as a combination optimization problem. It seeks final detection boxes under the guidance of an objective function. NMS is applied to each harmony to remove imprecise detection boxes, and the remaining boxes are used to calculate the fitness value. The remaining detection boxes in a harmony with highest fitness value are chosen as the final detection results. The standard Pattern Analysis, Statistical Modeling and Computational Learning Visual Object Classes dataset and the Microsoft Common Objects in Context dataset are used in all of the experiments. The proposed method is applied to two popular detection networks, namely Faster Region-based Convolutional Neural Networks and Region-based Fully Convolutional Networks. The experimental results show that the proposed method improves the average precision of these two detection networks. Moreover, the location performance and average recall of these two detectors are also improved.     

A hybrid occlusion free object tracking method using particle filter and modified galaxy based search meta-heuristic algorithm

An important problem in tracking methods is how to manage the changes in object appearance, such as illumination changes, partial/full occlusion, scale, and pose variation during the tracking process. In this paper, we propose an occlusion free object tracking method together with a simple adaptive appearance model. The proposed appearance model which is updated at the end of each time step includes three components: the first component consists of a fixed template of target object, the second component shows rapid changes in object appearance, and the third one maintains slow changes generated along the object path. The proposed tracking method not only can detect occlusion and handle it, but also it is robust against changes in the object appearance model. It is based on particle filter which is a robust technique in tracking and handles non-linear and non-Gaussian problems. We have also employed a meta-heuristic approach that is called Modified Galaxy based Search Algorithm (MGbSA), to reinforce finding the optimum state in the particle filter state space. The proposed method was applied to some benchmark videos and its results were satisfactory and better than results of related works.     

基于改进的布谷鸟搜索算法对分数阶生物系统的参数估计

近年来,非线性分数阶系统的参数估计问题已经在许多科学和工程领域特别是计算生物学中,引起了广泛的兴趣.本文针对分数阶生物系统的参数估计问题,将系统参数和分数阶导数同时作为独立的未知参数来进行估计,并提出了一种改进的布谷鸟搜索(improved cuckoo search, ICS)算法来求解该问题.在ICS算法中,通过引入一个自适应参数控制机制,同时结合反向学习方法,从而达到提高算法收敛速度和估计值精度的目的.最后,以三种经典的分数阶生物动力系统模型为例进行了数值仿真,其中还考虑了有测量误差和噪声数据的情形.仿真结果表明ICS算法具有良好的适应性、较高的收敛可靠性及精度,为求解非线性分数阶系统参数估计问题提供了一种有效工具.     

A tree search algorithm for the container loading problem

This paper presents a binary tree search algorithm for the three dimensional container loading problem (3D-CLP). The 3D-CLP is about how to load a subset of a given set of rectangular boxes into a rectangular container, such that the packing volume is maximized. In this algorithm, all the boxes are grouped into strips and layers while three constraints, i.e., full support constraint, orientation constraint and guillotine cutting constraint are satisfied. A binary tree is created where each tree node denotes a container loading plan. For a non-root each node, the layer set of its left (or right) child is obtained by inserting a directed layer into its layer set. A directed layer is parallel (or perpendicular) to the left side of the container. Each leaf node denotes a complete container loading plan. The solution is the layer set whose total volume of the boxes is the greatest among all tree nodes. The proposed algorithm achieves good results for the well-known 3D-CLP instances suggested by Bischoff and Ratcliff with reasonable computing time.