Dynamic Collaborative Cloud Service Platform: Opportunities and Challenges

This letter presents a model for a dynamic collaboration (DC) platform among cloud providers (CPs) that prevents adverse business impacts, cloud vendor lock‐in and violation of service level agreements with consumers, and also offers collaborative cloud services to consumers. We consider two major challenges. The first challenge is to find an appropriate market model in order to enable the DC platform. The second is to select suitable collaborative partners to provide services. We propose a novel combinatorial auction‐based cloud market model that enables a DC platform among CPs. We also propose a new promising multi‐objective optimization model to quantitatively evaluate the partners. Simulation experiments were conducted to verify both of the proposed models.     

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。     

多目标混沌进化算法

设计了多目标混沌进化算法(MCEA),在每一代遗传操作和外部档案调整完成之后,该算法从外部档案中随机选择部分个体,对这些个体的拷贝进行混沌搜索,以产生更多非劣解.将强度Pareto进化算法(SPEA)和SPEA2分别与基于Logistic映射的混沌搜索结合而产生的MCEAs应用于一些复杂多目标优化问题,计算结果表明,混沌的加入,明显改善了多目标进化算法(MOEA)各方面的性能.     

基于改进烟花算法的多目标多机器人任务分配

多机器人任务规划是多机器人系统研究的主要问题之一,多目标多机器人任务规划是指同时对多机器人系统的多个指标进行优化。近年来,启发式算法越来越多地被用来解决多目标问题。本文提出了一种基于改进烟花算法的多目标多机器人任务分配方法,并详细讨论了多目标解的排序方法和选择策略。为了验证该方法的性能,对7个实例进行了实验,并对该方法和其他四种多目标算法,Non-dominated Sorting Genetic Algorithm II (NSGA-II), Strength Pareto Evolutionary Algorithm 2 (SPEA2),Pareto Envelope-based Selection Algorithm (PESA ) 和一种改进的Strength Pareto Genetic Algorithm 2 (SPGA2)在S-metric指标上进行了比较。实验结果表明,在解集质量、解集覆盖度方面,基于改进烟花算法的多目标多机器人任务分配方法具有明显的优势。      

一种非均匀分布问题分布性维护方法

 几乎所有多目标进化算法(multi-objective optimization evolutionary algorithm,MOEA)都是针对Pareto最优面为均匀分布问题而言.然而现实中很多问题Pareto最优面是非均匀分布的,决策者希望得到一个与Pareto最优面分布类似的解集.现存算法并不能有效解决该问题.对此,提出一种针对于非均匀分布多目标优化问题的维护方法(non-uniformly diversity maintenance method,NUDMM).该方法定义一个反映个体分布"规则"程度的指标——杂乱度,并设计一种降低种群杂乱度的方法,在未知Pareto最优面分布规律情况下有效剔除造成种群混乱的个体.通过与NSGA-II和SPEA2在不同维数下8个非均匀函数上对比实验,表明NUDMM在有效保持问题真实分布的同时,具有良好的收敛性.     

Optimization of UPFCs using hierarchical multi-objective optimization algorithms

Optimal location, number, and settings of unified power flow controllers (UPFC) using various multi-objective optimization algorithms is presented in this paper. The UPFC parameters, locations and number are computed to maximize the voltage stability margin and minimize the real power losses at the same time. For this, developed hierarchical optimization versions of three recent multi-objective algorithms are proposed namely: non-dominated genetic algorithms (NSGA-II), non-dominated sorting particle swarm optimization (NSPSO) and Strength Pareto Evolutionary Algorithm 2 (SPEA2). The fuzzy logic is proposed to extract the best compromise solution from the Pareto set. The proposed algorithms are applied to IEEE 30-bus power system. The line flow and load bus voltage limits are taken into account. The obtained results show that the installation of the UPFC in the power system minimizes the power losses, enhances the static voltage stability, and improves the voltage profiles. Furthermore, the proposed methods are able to solve a hard discrete?Ccontinuous constrained multi-objective optimization problem. In addition, they do not show any limitation on the number of objective functions under consideration.     

Genetic Algorithm-based Adaptive Optimization for Target Tracking in Wireless Sensor Networks

In this paper, we address the problem of genetic algorithm optimization for jointly selecting the best group of candidate sensors and optimizing the quantization for target tracking in wireless sensor networks. We focus on a more challenging problem of how to effectively utilize quantized sensor measurement for target tracking in sensor networks by considering best group of candidate sensors selection problem. The main objective of this paper is twofold. Firstly, the quantization level and the group of candidate sensors selection are to be optimized in order to provide the required data of the target and to balance the energy dissipation in the wireless sensor network. Secondly, the target position is to be estimated using quantized variational filtering (QVF) algorithm. The optimization of quantization and sensor selection are based on the Fast and Elitist Multi-objective Genetic Algorithm (NSGA-II). The proposed multi-objective (MO) function defines the main parameters that may influence the relevance of the participation in cooperation for target tracking and the transmitting power between one sensor and the cluster head (CH). The proposed algorithm is designed to: i) avoid the problem lot of computing times and operation counts, and ii) reduce the communication cost and the estimation error, which leads to a significant reduction of energy consumption and an accurate target tracking. The computation of these criteria is based on the predictive information provided by the QVF algorithm. The simulation results show that the NSGA-II -based QVF algorithm outperforms the standard quantized variational filtering algorithm and the centralized quantized particle filter.     

一种新颖的共形阵非均匀子阵的优化算法

提出了一种新的同时对共形阵非均匀子阵分区和子阵幅度激励进行优化的多目标进化算法，为此设计了新的多目标函数，通过在改进的强度 Pareto 进化算法(SPEA2)使用克隆选择算子和双交换遗传操作算子，从而提高搜索效率和收敛性，可以有效改善整个阵列的辐射特性。 在系统仿真中，结合工程化实际应用，本文提出的 MOEA 算法对 20×20 阵列进行非均匀子阵分区和对各个子阵的幅度激励优化，仿真结果表明其天线阵列在扫描空域的峰值旁瓣电平(PSLL) 以及方位和俯仰波束宽度等性能参数得到明显改善，该方法对改善整个阵列的辐射特性是有效的。     

Multi-objective test case prioritization based on multi-population cooperative particle swarm optimization

Test case prioritization (TCP) technique is an efficient approach to improve regression testing activities. With the continuous improvement of industrial testing requirements, traditional single-objective TCP is limited greatly, and multi-objective test case prioritization (MOTCP) technique becomes one of the hot topics in the field of software testing in recent years. Considering the problems of traditional genetic algorithm (GA) and swarm intelligence algorithm in solving MOTCP problems, such as falling into local optimum quickly and weak stability of the algorithm, a MOTCP algorithm based on multi-population cooperative particle swarm optimization (MPPSO) was proposed in this paper. Empirical studies were conducted to study the influence of iteration times on the proposed MOTCP algorithm, and compare the performances of MOTCP based on single-population particle swarm optimization (PSO) and MOTCP based on non-dominated sorting genetic algorithm II (NSGA-II) with the MOTCP algorithm proposed in this paper. The results of experiments show that the test case prioritization algorithm based on MPPSO has stronger global optimization ability, is not easy to fall into local optimum, and can solve the MOTCP problem better than test case prioritization algorithm based on the single-population PSO and NSGA-II.     

Path planning algorithm for WCE with joint energy replenishment and data collection based on multi-objective optimization

Considering limited energy of the wireless charging equipment (WCE) in wireless rechargeable sensor network,an energy replenishment strategy and a data collection strategy are designed.On the basis of these,a path planning model for WCE with functions of joint energy replenishment and data collection based on multi-objective optimization is constructed with two optimization objectives,maximizing the total energy utility of WCE and minimizing the average delay of data transmission of all the sensor nodes in the network.To deal with it,a multi-objective ant colony optimization algorithm based on elitist strategy was proposed,where the state transition strategy and the pheromone updating strategy were improved.Then,the Pareto set was obtained in terms of this multi-objective optimization problem.The parameter setting of ant colony algorithm’s effects on the proposed algorithm were analyzed under 20 sensor nodes.50 groups of contrastive experiments show that the average number of energy utilization obtained by ES-MOAC algorithm is 4.53% higher than that of NSGA-II algorithm.The average number of average delay of all node data transmission obtained by ES-MOAC algorithm is 5.12% lower than that of NSGA-II algorithm.     

基于BiLSTM代理模型的RFID标签天线快速多目标设计

为快速完成超高频(UHF)标签天线多目标设计,构建了基于双向长短期记忆(BiLSTM)神经网络的新型天线性能预测代理模型,并使用带精英策略的非支配排序遗传算法(NSGA-II)配合静态惩罚对RFID标签天线进行多目标寻优。首先按照RFID标签天线延伸的趋势将天线结构序列化并依次输入BiLSTM网络结构,结合响应集训练出适用于RFID标签天线的代理模型。进一步地,为最大程度搜索可行域内,尤其是可行域边界的所有标签天线形式,在NSGA-II算法中引入静态惩罚,最终完成RFID标签天线低回波损耗、小型化、宽频带的多目标快速设计。设计实例表明,该方法在超高频RFID标签天线领域的预测精度、计算代价等方面综合表现优于现有天线设计方法,具有适用性和实用价值。     

Analog active filter design using a multi objective genetic algorithm

The selection of the correct values for passive elements, resistors, and capacitors, is an important task in analog active filter design. The classic method of choosing passive elements is a difficult task and can lead to errors. To reduce the incidence of error and human effort evolutionary optimization techniques are used to select the values of capacitors and resistors. However, due to the single objective optimization technique, these are not well suited to optimize different filter parameters. For this reason, the performance of a multi-objective genetic algorithm named non-dominated sorting genetic algorithm II (NSGA-II) against the different single objective algorithms is evaluated. Two analog active filters: A fourth order Butterworth and a second order state variable filter with the operational amplifiers in their cores are used for testing purposes. In both cases two different objects are chosen along with eight components as variables to be optimized. The component values are compatible with the E12, E24 and E96 series using NSGA-II. The computation results are better in terms of design error and allow for better resistor and capacitor choice. To reach the same or better results the NSGA-II needs fewer generations compared with other genetic algorithms for this problem.     

多目标猫群优化算法支持下的云计算任务调度

针对云环境下任务调度易出现多目标冲突的问题,提出一种改进的基于猫群的多目标优化算法。该算法模拟猫的行为模式,采用基于线性混合比率的猫行为选择方式来提高全局搜索和局部寻优能力;并在迭代过程中结合任务完成时间和任务费用支出,引入一个可调节的多目标集成效用函数,实现了资源与任务的智能调度。实验结果表明,所提算法不仅求解质量高,且在求解速度和调度消耗方面均优于多目标遗传算法和多目标粒子群算法。     

基于改进遗传算法的云教学平台研究

云计算技术迅猛发展,云计算辅助教学平台应运而生,具有网络化的海量教学数据资源存储与计算功能和瘦客户端等显著优点,云辅助教学平台数据量和用户量巨大的特点决定了其作业类型的多样性和数据密集性,云辅助教学平台的设计重点在高效率的资源管理和调度。文中设计云计算辅助教学平台的体系结构,并对云平台作业调度的原有自适应遗传算法做出改进,以传统遗传算法做基础,综合数据公平和本地性选择遗传基因,相比较传统算法,在响应用户需求上更高效。仿真实验结果显示改进后算法更能体现公平性、并提高了效率,更适于云计算机环境。     

基于极坐标变换的改进NSGA-II算法

在实际工程中存在着大量的多目标优化问题,而由于大部分多目标优化问题有无穷多个最优解,且传统的数学方法如梯度下降法和牛顿法,无法求解一些不可微或表达式过于复杂的多目标优化问题。为避免以上局限,NSGA-II作为求解多目标优化问题的代表算法被提出,但NSGA-II算法仍存在着一些不足,如变异算子功能过于简单,降低了Pareto最优解的多样性。为增加Pareto最优解的多样性,文中设计了一种基于极坐标变换的改进NSGA-II算法,该算法可使得Pareto最优解分布更加均匀,并最终通过标准的测试函数验证了算法的有效性。     

基于Pareto多目标优化的光纤Bragg光栅传感网络的波长分配

针对现有波分复用(WDM)的光纤Bragg光栅(FBG) 传感网络的复用瓶颈,运用Pareto多 目标优化理论,建立了基于带宽重叠技术的FBG传感网络优化模型。通过非支配排序遗传算 法Ⅱ(NSGA-Ⅱ)进化算法求解Pareto 最优曲线,为网络中的每个FBG传感器合理地分配Bragg波长的工作范围,以最小的光谱重叠 程度换取 光源带宽资源的最大节约。仿真和实验结果表明,得到Pareto最优曲线为不同程度的光 谱重叠找到了最优的Bragg波长配置方案,有效地提高了FBG传感网络的WDM能力。     

一种求解SLA等级感知服务组合问题的多目标离散粒子群优化算法

针对SLA等级感知服务组合问题,本文提出了一种求解该问题的多目标离散粒子群算法(MDPSO),建立了多目标粒子群算法优化模型.根据该问题的特征,对粒子更新策略进行重新设计;并且提出粒子变异策略以抑制群体的早熟收敛增强群体的全局搜索能力.另外,提出了一种基于约束支配关系的局部搜索策略并将其结合到MDPSO算法,形成算法MDPSO+.最后对MDPSO算法的参数设值进行了分析,并将算法MDPSO、MDPSO+与最近提出的求解该问题的E³-MOGA算法及NSGA-II算法在不同规模的测试用例上进行了实验对比,结果表明算法MDPSO+能够更加有效的解决该问题.     

A New Automated Design Method Based on Machine Learning for CMOS Analog Circuits

A new simulation based automated CMOS analog circuit design method which applies a multi-objective non-Darwinian-type evolutionary algorithm based on Learnable Evolution Model (LEM) is proposed in this article. The multi-objective property of this automated design of CMOS analog circuits is governed by a modified Strength Pareto Evolutionary Algorithm (SPEA) incorporated in the LEM algorithm presented here. LEM includes a machine learning method such as the decision trees that makes a distinction between high- and low-fitness areas in the design space. The learning process can detect the right directions of the evolution and lead to high steps in the evolution of the individuals. The learning phase shortens the evolution process and makes remarkable reduction in the number of individual evaluations. The expert designer’s knowledge on circuit is applied in the design process in order to reduce the design space as well as the design time. The circuit evaluation is made by HSPICE simulator. In order to improve the design accuracy, bsim3v3 CMOS transistor model is adopted in this proposed design method. This proposed design method is tested on three different operational amplifier circuits. The performance of this proposed design method is verified by comparing it with the evolutionary strategy algorithm and other similar methods.     

多目标优化算法在多分类中的应用研究

 Cai等人用多目标粒子群算法(MOPSO)优化多目标聚类学习和分类学习框架(MSCC)的多目标问题时,种群只能得到少量的非支配解,不利于种群优化.而在此情况下,NSGA-II由于采用了Pareto排序的方法,种群中会保留大量优秀的支配解,有利于种群优化,所以本文引进了NSGA-II优化MSCC框架的多目标问题.通过对数据集的测试,验证了在NSGA-II的优化下,对于大多数测试问题,MSCC框架设计的分类器的最大分类正确率高于MOPSO优化MSCC框架的结果.进而对实验结果做了进一步分析,发现了最大正确率不随多目标优化算法的优化过程而提高的问题.