差分演化的收敛性分析与算法改进

为了分析差分演化(differential evolution,简称DE)的收敛性并改善其算法性能,首先将差分算子(differential operator,简称DO)定义为解空间到解空间的笛卡尔积的一种随机映射,利用随机泛函理论中的随机压缩映射原理证明了DE的渐近收敛性;然后,在"拟物拟人算法"的启发下,通过对DE各进化模式的共性特征与性能差异的分析,提出了一种具有多进化模式协作的差分演化算法(differential evolution with multi-strategy cooperating evolution,简称MEDE),分析了它所具有的隐含特性,并在多模式差分算子(multi-strategy differential operator,简称MDO)定义的基础上证明了它的渐进收敛性.对5个经典测试函数的仿真计算结果表明,与原始的DE,DEfirDE和DEfirSPX等算法相比,MEDE算法在求解质量、适应性和鲁棒性方面均具有较明显的优势,非常适于求解复杂高维函数的数值最优化问题.     

一种具有混合编码的二进制差分演化算法

差分演化(DE)是Storn和Price于1997年提出的一种基于个体差异重组思想的演化算法,非常适用于求解连续域上的最优化问题.首先引入"差异算子"等概念,给出DE的一种简洁算法描述,并分析了它所具有的特性.然后,为了使DE能够求解离散域上的最优化问题,基于数学变换思想引入"辅助搜索空间"和"个体混合编码"等概念,通过定义一个特殊的满射变换,在辅助搜索空间的作用下将连续域上的高效差分演化搜索变换为离散域上的同步演化搜索,由此提出了第1个二进制差分演化算法:具有混合编码的二进制差分演化算法(HBDE).接着,给出了HBDE的依概率收敛和完全收敛的定义,并利用离散Markov随机理论证明了HBDE是完全收敛的. HBDE不仅完全具有DE的各种特性和所有优点,而且非常适用于求解离散域上的最优化问题,对随机生成的大规模3-SAT问题实例和典型0/1背包问题实例的数值计算表明:该算法具有很好的全局收敛性和稳定性,其性能远远超过二进制粒子群优化算法和遗传算法.     

一种简单有效的求解TSP的混合差分进化算法

设计了基于标准差分进化算法(differential evolution,DE)与遗传算法(genetic algorithm,GA)的混合差分进化算法(hybrid DE,HDE),同时用典型的测试函数对HDE进行性能测试。针对旅行商问题(traveling salesman problem,TSP)的求解难题,给出了采用位置—次序转换策略和HDE的有效求解方法,并测试了Oliver 30个城市的TSP。仿真结果表明,与DE和GA相比,HDE的优势在收敛率、平均最优解以及耗时上都很明显,证明了HDE在解决TSP问题上的有效性和稳定性。     

差分演化算法各种更新策略的对比分析

差分演化算法（differential evolution,DE）是一种模拟生物演化过程的随机搜索方法,具有收敛速度快,鲁棒性好等优点。目前DE有多种交叉和变异策略,它们在求解各类优化问题时表现出各自不同的性能。介绍了10种差分演化算法的更新策略,并利用标准测试函数集对它们进行了全面与系统的实验比较。通过分析采用这些策略的DE算法在不同解空间及进化各阶段的收敛曲线特点,对比总结了不同版本的DE算法在各类环境下的搜索性能。该研究一方面能够为DE算法的实际应用提供技术指导,帮助学者选择合适的DE更新策略以更好地解决工程问题;另一方面能够为新型DE更新策略的开发和自适应DE算法的设计提供理论基础。     

基于拉马克进化的差分进化算法求解KPC问题

具有单连续变量的背包问题（knapsack problem with a single continuous variable,KPC）是标准0-1背包问题的自然推广,在KPC中背包容量不是固定的,因此其求解难度变大。针对现有差分进化（differential evolution,DE）算法在高维KPC实例上求解精度不够高的不足,提出基于拉马克进化的DE（Lamarckian evolution-based DE,LEDE）算法,将贪心修复优化算子产生的改进遗传给后代,以加快DE算法的收敛速度,提高DE算法在高维KPC实例上的求解精度。同时,在贪心修复优化算子中引入基于价值的贪心优化策略,用于优化使用基于价值密度的贪心修复策略生成的可行解,以帮助算法跳出局部最优。在40个KPC实例上对LEDE算法进行了实验分析,结果表明拉马克进化和基于价值的贪心优化策略能够提高LEDE算法的求精能力,LEDE算法在获得最优解和平均解方面均优于其他智能优化算法。     

基于模拟退火的混合差分进化算法及其在联合补货-配送集成优化中的应用

针对差分进化 (Differential evolution, DE)算法搜索效率较低和容易陷入局部最优的缺点,设计了基于SA的混合差分进化算法(SA-based Hybrid DE, SAHDE),以提高DE算法的全局寻优能力。该算法采用自适应变异算子和交叉算子,并结合模拟退火(Simulated Annealing, SA)算法的Metropolis 准则。首先通过标准测试函数对改进的SAHDE进行性能测试,证明了该算法比DE、自适应混合DE (Adaptive Hybrid DE, AHDE)和遗传算法(Genetic Algorithm, GA)更有效。进而将该算法运用到联合补货-配送集成优化(典型NP-hard)问题的求解中,通过大规模的算例分析,证实SAHDE在解决联合补货-配送优化问题比DE、AHDE和GA更有效。     

基于N阶近邻分析的自适应差分进化算法

针对差分进化算法在求解多模优化问题解可靠性较低的问题,在N阶近邻理论分析及参数整定的基础上,提出一种基于N阶近邻分析的自适应差分进化算法（N--NNADE）.N--NNADE算法在缺少先验知识的情况下,通过分析群体个体间的N阶最短近邻计算种群的全局分布,并利用阶跃信息自适应统计获得种群数量;同时采用K--means算法划分种群,进一步引入不同种群间的交叉变异思想以及父子代同种群则替换最差个体的选择策略实现种群间的协同进化.通过获取更多的全局最优解和部分高质量的局优解来提高算法的可靠性.20个优化问题的数值研究结果表明N--NNADE算法具有比DE（differential evolution）,DERL（differential evolution algorithm withrandom localizations）,ADE（adaptive differential evolution）算法更适合求解复杂的高维多模优化问题.     

求解约束优化问题的ε-DE 算法

差分进化(differential evolution,简称DE)算法解决约束优化问题(constrained optimization problems,简称COPs)时通常采用可行解优先的比较规则,但是该方法不能利用种群中不可行解的信息.设计了可以利用不可行解信息的ε-DE算法.该算法通过构造一种比较准则,使得进化过程可以充分利用种群中优秀不可行解的信息.该准则通过引入种群约束允许放松程度的概念,在进化初始阶段使可行域边界上且拥有较优目标函数的不可行解进入种群;随着进化代数增加,种群约束允许放松程度不断减小,使得种群中不可行解数量减少,直到种群约束允许放松程度为0,种群完全由可行解组成.此外,还选择了一种改进的DE算法作为搜索算法,使得进化过程具有较快的收敛性.13个标准Benchmark函数实验仿真的结果表明:ε-DE算法是目前利用DE算法解决COPs问题中效果最好的.     

广义逆向学习方法的自适应差分算法

针对差分算法(differential evolution,DE)在解决高维优化问题时参数设置复杂、选择变异策略困难的现象,提出了广义逆向学习方法的自适应差分进化算法(self-adaptive DE algorithm via generalized opposition-based learning,SDE-GOBL)。利用广义的逆向学习方法(generalized opposition-based learning,GOBL)来进行多策略自适应差分算法(Self-adaptive DE,Sa DE)的初始化策略调整,求出各个候选解的相应逆向点,并在候选解和其逆向点中选择所需要的最优初始种群,然后再进行自适应变异、杂交、选择操作,最后通过CEC2005国际竞赛所提供的9个标准测试函数对SDE-GOBL算法进行验证,结果证明该算法具有较快的收敛速度和较高的求解精度。     

具有自加速与变邻域搜索的差分演化算法

在分析差分演化（DE）进化方式基础上,首先利用自加速性改进差异算子与选择算子,然后结合变邻域搜索改善算法的局部搜索能力,提出了一种具有自加速特性与变邻域搜索能力的差分演化算法(SAVNDE);基于DE的三种进化模式,利用5个Benchmark测试函数进行对比计算,实验结果表明：SAVNDE在保持了DE原有特性基础上,以较快的速度获得更好的结果。     

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.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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