自适应种群更新策略的多目标粒子群算法

针对粒子种群较差的局部搜索能力,提出了一种自适应种群更新策略的多目标粒子群算法。该算法在每次种群进行迭代时,根据种群的多样性测度以及每个粒子的适应度值,自适应地改变速度权重,以此来提高种群粒子在局部搜索时的活性,使算法具有较强的局部搜索能力同时又保留了足够的全局搜索能力。最后利用多组经典测试样例进行仿真,并与传统的粒子群算法以及速度线性衰减算法做比较,在单目标优化中,自适应粒子群算法能够更快地寻找最优位置;在多目标优化中,自适应粒子群算法能够更快速地收敛于帕累托最优边界。     

动态改变惯性权重的自适应粒子群算法

惯性权重是平衡粒子群算法中平衡全局搜索能力与局部搜索能力的重要参数.为实现快速收敛与并避免陷入局部最优,分析了PSO算法中的惯性权重与种群规模、粒子适应度以及搜索空间维度这三者的关系,并把粒子惯性权重定义为这三者的函数以改进PSO算法.该算法在每次迭代后根据此函数更新每个粒子的惯性权重,实现了自适应调整全局搜索能力与局部搜索能力,并结合动态管理种群的策略提出了改进的粒子群算法.通过在多个常用测试函数上与已有惯性权重调整算法测试比较,证明新算法具有较强的全局寻优能力与较高的搜索效率.     

融合吸引排斥和双向学习的改进粒子群算法

针对粒子群算法在计算时存在收敛速度慢、易陷入局部收敛等缺陷,提出了一种融合吸引排斥和双向学习的改进粒子群算法来提高算法的寻优能力。双向学习策略扩大了粒子的搜索范围、丰富了种群多样性;在吸引-排斥策略中,粒子能够分别被全局最优粒子和全局最差粒子所引导进而朝着更优的方向进化,提高了算法的局部寻优性能和收敛能力。同时,在双向学习策略中,为了克服单一性的学习因子和惯性权重在优化复杂函数时无法很好地调节寻优进程的问题,提出了双重自适应策略,更好地平衡群体中粒子的搜索行为。最后利用标准测试函数对该算法进行仿真验证,并与其他两种改进的算法对比。实验结果表明,在相同的实验条件下,改进后的粒子群算法在寻优能力和收敛速度方面具有明显优势。     

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。     

基于质心和自适应指数惯性权重改进的粒子群算法

针对标准粒子群优化算法易出现早熟收敛及寻优精度低等缺陷,提出一种基于双质心和自适应指数惯性权重的改进粒子群算法（DCAEPSO）。算法使用粒子搜到的最优解和当前解构造加权的种群质心和最优个体质心,结合使用自适应指数惯性权重调整了速度更新公式。通过几个典型测试函数仿真及Friedman和Holm检验,实验结果显示DCAEPSO比其他粒子群算法寻优能力强。     

基于遗传交叉改进粒子群算法的充电站布局

为了合理地规划城市电动汽车充电站布局,采用一种基于遗传交叉改进粒子群算法的寻优处理方案。在传统粒子群算法的基础上,引入局部极值对速度更新公式进行优化,采用自适应惯性权重,并且对当前种群的最优解和每个粒子最优解进行交叉操作产生新解。最后通过改进后算法对城市算例进行求解。结果验证了模型的有效性和准确性,表明改进算法在保持全局最优解的同时能提高70%收敛速度,有效降低总成本、提高便利性。     

一种引入复合形算子的变异粒子群算法

针对粒子群算法存在的收敛速度较慢和早熟收敛两大难题提出了一种新的改进型粒子群算法：搜索初期由粒子群算法进行全局寻优,当判断粒子群体已经进入局部最优区域时,引入复合形算法迅速达到局部收敛,从而有效地提高粒子群算法的局部搜索能力。同时引入自适应变异惯性权重提高摆脱局部最优的能力,增加种群的多样性。通过典型优化函数的实验验证,该算法是一种兼顾局部性能和全局搜索能力的高效算法。     

云自适应粒子群算法

文中提出了云自适应粒子群优化（CAPSO）算法,根据粒子适应度值把种群分为三个子群,分别采用不同的惯性权重生成策略,由X条件云发生器自适应调整普通子群粒子的惯性权重,由于云模型云滴具有随机性和稳定倾向性特点,使惯性权重既具有传统的趋势性,满足快速寻优能力,又具有随机性,在提高收敛速度和保持种群多样性之间做了一个很好的权衡。通过典型函数优化实验表明,与标准粒子群算法相比,CAPSO具有较高的计算精度和较快的收敛速度。     

基于环境选择和配对选择的多目标粒子群算法

为了使多目标粒子群算法中种群粒子能够快速地收敛于怕累托最优边界,针对标准多目标粒子群算法中缺乏粒子评价标准以及种群个体历史最优值位置和全局最优值位置选择问题,提出了一种基于环境选择和配对选择策略的多目标粒子群算法.该算法在每次迭代时,采用SPEA2中的环境选择和配对选择策略及适应度值计算方法,以此来提高种群粒子之间的信息交换力度,减少标准多目标粒子群算法中大量的随机性,使种群粒子能够更快速地收敛于怕累托最优边界.经典测试函数的仿真实验结果表明,在标准多目标粒子群算法中运用SPEA2的环境选择、配对选择策略和适应度值计算方法,能够使种群粒子更快速地收敛于帕累托最优边界,验证了算法改进的可行性和有效性.     

基于RMSprop的粒子群优化算法

粒子群算法对所有粒子采用相同的惯性权重,忽视了单个粒子的特性,导致收敛精度偏低且易陷入局部最优.结合RMSprop算法中对每一个维度进行自适应设置的策略,提出一种自适应惯性权重粒子群优化算法RMSPSO.考虑粒子每一个维度的速度变化及动量,进行自适应动态惯性权重设置,使算法在全局寻优和局部寻优之间达到良好平衡.选取10个典型测试函数,将改进后的粒子群算法(RMSPSO)与4个主流粒子群算法进行实验对比分析,实验结果表明,在单峰、多峰和组合函数上,RMSPSO算法在收敛速度和收敛精度上取得了明显进步.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

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.