基于种群多样性模糊控制的粒子群算法

关于优化粒子群算法问题,针对标准粒子群算法前期收敛速度过快,后期容易陷入局部最优解的问题,提出一种种群多样性模糊控制的粒子群算法。为了控制种群多样性的变化,提高算法跳出局部最优解的性能,在算法中加入模糊控制器和位置跳变策略,通过控制参数的变化来控制粒子的速度、位置和种群多样性的变化,使算法从全局探测平稳过渡到局部开采。仿真结果表明,改进算法能有效避免陷入局部最优解,且对高维函数优化时效果更为明显,是一种高效的优化算法。     

一种克服局部最优的收缩因子PSO算法

收缩因子粒子群优化算法容易陷入局部最优并出现早熟收敛的现象。为此,提出一种改进的收缩因子粒子群优化算法。该算法引入速度因子和位置因子参数,若粒子向全局最优接近且速度小于设定的速度因子,则认为该粒子可能出现停滞,从而对该粒子进行初始化,以增强粒子活力。在算法陷入局部最优时,通过该方法驱散粒子以提高种群多样性,避免产生早熟收敛现象。对多峰标准测试函数进行仿真实验,结果表明,该算法能提高收敛精度,有效避免算法陷入局部最优。     

改进的变尺度混沌粒子群算法及其应用

针对粒子群算法(PSO)存在局部最优及后期收敛速度慢等问题,提出一种改进的变尺度混沌粒子群算法(IMCPSO).该算法初期,在整个解空间对最优粒子进行变尺度混沌扰动,以防止陷入局部最优;算法后期,则以最优粒子为中心引入变尺度混沌扰动,以提高算法收敛速度.当算法一旦陷入局部最优时,采用混沌粒子替代部分种群粒子以增加粒子多样性,使算法尽快跳出局部最优.基于benchmark测试函数的仿真结果表明,所提算法与基本粒子群算法(SPSO)和变尺度混沌粒子群算法(MCPSO)相比,具有明显好的搜索精度和收敛速度.最后,将该算法应用于电路故障诊断实验中的支持向量机参数优化问题,实验结果说明了其应用价值.     

一种新的自适应动态文化粒子群优化算法

为了克服粒子群优化算法在解决复杂问题时易陷入局部最优的缺陷, 提出了一种新的自适应动态文化粒子群优化算法。该算法引入评价粒子群早熟收敛程度的指标来判断种群空间粒子群状态, 以确定影响函数对种群空间粒子群的作用时机, 当算法陷入局部最优时, 自适应地利用影响函数对种群空间进行变异更新, 从而有效发挥文化粒子群算法的双演化双促进机制。并且根据种群的早熟收敛程度自适应地调整粒子的惯性权重, 使种群在进化过程中始终保持惯性权重的多样性, 在算法的全局收敛性与收敛速度之间作一个很好的折中。最后对四个经典的测试函数进行仿真, 结果表明该算法具有很强的搜索能力, 收敛速度和收敛精度也有所提高。     

基于Cat混沌与高斯变异的改进灰狼优化算法

针对基本灰狼优化算法在求解复杂问题时同样存在依赖初始种群、过早收敛、易陷入局部最优等缺点,提出一种改进的灰狼优化算法应用于求解函数优化问题中。该算法首先利用混沌Cat映射产生灰狼种群的初始位置,为算法全局搜索过程的种群多样性奠定基础;同时引入粒子群算法中的个体记忆功能以便增强算法的局部搜索能力和加快其收敛速度;最后采用高斯变异扰动和优胜劣汰选择规则对当前最优解进行变异操作以避免算法陷入局部最优。对13个基准测试函数进行仿真实验,结果表明,与基本GWO算法、PSO算法、GA算法以及ACO算法相比,该算法具有更好的求解精度和更快的收敛速度。     

基于分数阶麻雀搜索优化OTSU肺组织分割算法

针对传统粒子群算法应用于肺组织分割时寻优慢且易陷入局部最优的问题,提出了一种基于分数阶麻雀搜索优化的最大类间差法(OTSU)肺组织分割算法.采用分数阶微积分算法优化麻雀搜索算法,根据麻雀的位置信息,引入自适应分数阶阶次以自适应地调整分数阶阶次,加快算法收敛速度;采用灰度级-梯度二维直方图以减小二维直方图的计算量和麻雀的搜索范围;算法实现过程中,利用孔洞填充算法去除CT图像背景,采用形态学操作去除噪音并修补病变区域产生的孔洞.实验表明,所提算法达到稳定的收敛次数相较于粒子群优化OTSU算法、分数阶粒子群优化OTSU算法、麻雀搜索优化OTSU算法分别减少了22.75％,13.75％,2.25％,因此所提算法在保证分割精度的同时,提高了算法的收敛速度.     

基于反向学习和精英提升的无速度项动态粒子群算法

针对粒子群优化算法在处理复杂优化问题时搜索精度低、收敛速度慢且易陷入局部最优的问题，提出一种基于反向学习和精英提升的动态多种群无速度项粒子群算法。首先基于无速度项的粒子位置更新模式，动态划分子群并采用不同的进化策略，利用反向学习为子群拓宽搜索范围，保证种群多样性的同时避免粒子过早陷入局部最优。然后为充分利用优秀粒子的信息并提高搜索精度，改进精英提升策略优化个体历史最优粒子，使用差分进化算法对种群最优粒子进行更新。最后通过CEC2006提出的22个测试函数进行性能测试。结果表明，本文提出的算法相比于其他算法在搜索精度和稳定性上拥有更加出色的性能，并能有效提升算法收敛速度。     

基于改进粒子群算法的电力系统无功优化

针对传统粒子群算法易陷入局部最优解、收敛速度慢的缺点,提出一种基于信息分享策略的改进型粒子群算法,并首次将其应用于电力系统无功优化问题.改进的粒子群算法通过调整学习因子而获得合理有效的收敛速度;采用信息分享策略以保证种群的多样性;在位置的更新过程中加入扰动项,从而避免算法陷入局部最优解.用改进型粒子群算法对IEEE-14节点标准测试系统进行无功优化计算,实验结果表明:与其他算法相比,该改进粒子群算法具有较强的全局寻优能力,且收敛速度快,鲁棒性好,能有效地解决电力系统无功优化问题.     

基于粒子群算法的遗传算法研究

针对传统遗传算法存在的早熟收敛和易陷入局部最优解的问题,提出了一种基于粒子群算法的遗传算法,其原理是用粒子群算法来构造变异算子和进行种群分割.通过对三个典型多峰值函数的优化来评估算法性能.实验结果表明,该算法能很好地保持种群的多样性和克服早熟现象,显著提高遗传算法的收敛速度.     

基于分数阶达尔文粒子群FODPSO算法的图像分割

图像分割主要用于提取用户感兴趣的目标,是图像分类和识别的基础。采用一种基于分数阶达尔文粒子群算法的图像分割方法,该算法采用分数阶微积分控制系统收敛性,能够对n尺度图像进行n-1个阈值寻优计算。实验结果表明,对比于APSO、CFPSO算法,该算法具有收敛速度快、稳定性强、精度高、全局寻优等特点,有效地克服了传统算法易陷入局部最优和收敛速度慢等缺陷,可满足实际工程需求。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate