基于改进PSO算法的SVM在甲烷测量中的应用

针对甲烷气体定量分析过程中,传统SVM模型预测精度低、收敛速度慢等问题,提出了一种基于改进PSO算法的SVM回归模型.该模型在传统PSO算法寻优的基础上,引入动量项的同时增加随机粒子个体极值的追随因子,使粒子不仅追随全局最优解和局部最优解,还跟随种群中任一粒子的个体极值,使得寻优算法后期收敛速度较快,不易陷入局部最小值.实验中,对0~5.05%浓度的25组标准甲烷样气进行建模分析,并与传统PSO算法寻优模型和Grid搜索法寻优模型进行对比.结果表明,采用改进PSO算法建立的SVM回归模型均方根误差小,收敛速度快.     

具有随机附加项的PSO改进算法

在粒子群算法的基础上引入第3方随机项:随机数和全局最优、自身最优的差值的乘积项,对算法中的速度-位置更新方程进行了改进,更好地保持粒子群的多样性,使算法可以不断地进化,提高算法的收敛速度,避免过早陷入局部最优解的现象.分别采用Sphere、Rosenbrock、Griewank和Rastrigrin4个标准函数对其进行测试.对比结果表明引入第3方随机项的PSO基本模型和收敛因子模型比传统模型的最优适宜度精度和优化收敛速度都有所提高.因此,改进的算法表现出更强的求解能力.     

基于自适应惯性权重的均值粒子群优化算法

针对粒子收敛速度慢、搜索精度不高和算法性能在很大程度上依赖参数选取等缺点,提出了一种基于自适应惯性权重的均值粒子群优化算法。对算法中的惯性权重参数采用动态自适应变化方式,在迭代过程中根据粒子适应度差值将种群划分为三个等级,对不同等级的粒子采用不同的惯性权重策略,使粒子能根据自己所处的位置选择合适的惯性权重值,更快地收敛到全局最优位置;同时分别用个体极值和全局极值的线性组合取代PSO算法中的全局最优位置与个体最优位置。通过实验仿真与对比,验证了新算法性能优于标准PSO及其它一些改进的PSO算法,能够用较少的迭代次数找到最优解,具有更快的收敛速度和更高的收敛精度。     

基于A-VFSA粒子发生器的PSO算法的研究

对超快速模拟退火算法进行改进(A-VFSA),并以此为粒子发生器,提出了PSO-PG算法.该算法通过粒子发生器对搜索域内粒子进行改进,从而生成一个精英粒子池;并根据随机策略从粒子池中选择粒子,作为初始种群,采用PSO算法进行优化,得到全局最优解.相比于标准PSO算法和LDW算法,PSO-PG算法拥有更好的稳定性和优化精度,能够更加快速地收敛到全局最优解,在一定范围内几乎不依赖于初始参数的选择.     

基于排列的微粒群优化算法

针对基本微粒群优化算法(PSO)存在陷入局部最优的问题,提出一种基于排列的改进微粒群算法(RPSO).该算法对每次迭代过程中的个体历史最优解按照适应值的优劣顺序排列,然后选择若干个较优的个体历史最优解作为候选解,再以概率方式在候选解中确定群体历史最优解的位置.RPSO算法使基本PSO算法易于陷入局部最优的问题,得到有效的缓解.为了分析算法的性能,对几种典型的非线性函数进行了测试.实验结果表明,RPSO算法比基本PSO算法具有更好的寻优能力.     

改进PSO算法的性能分析与研究*

分析了粒子群优化(PSO)算法的进化式,针对其容易发生早熟、收敛速度慢、后期搜索性能和个体寻优能力降低等缺点,结合遗传算法的思想,提出一种新的混合PSO算法——遗传PSO(GAPSO)。该算法是在PSO算法的更新过程中,对粒子速度引入遗传算法的变异操作,对粒子位置引入遗传算法交叉操作。对速度的变异降低了算法后期因种群过于密集而陷入局部最优的可能,对位置的交叉使得父代中优良个体的基因能够更好地遗传给下一代,从而得到更优、更多样化的后代,加快进化过程,提高了收敛速度和群体搜索性能。选取了其他几种典型的改进PS     

改进混沌PSO算法的电力系统最优潮流计算

电力工业的市场化改革对最优潮流（Optimal Power Flow,OPF）的计算精度和速度提出了更高的要求。在分析最优潮流理论及其算法的基础上,对比一些经典解算法,引入粒子群优化算法（PSO）来计算发电厂成本耗费问题。考虑到传统PSO算法处理OPF约束条件时,对随机粒子个体的质量和速度的选取不能保证,且收敛速度慢,并容易陷入局部最优解,提出改进的混沌粒子群算法,即利用混沌运动特性来改进粒子群算法。利用该算法与其他算法对IEEE5节点算例进行分析比较,结果表明改进的混沌微粒群优化算法可较好处理最优潮流约束条件,有效提高了PSO算法的全局收敛能力和计算精度。在处理最优潮流问题上具有一定的有效性和优越性。     

基于粗糙集理论的PSO-IOIF-Elman神经网络建模

针对系统级仿真中功放建模的优缺点,结合粗糙集理论提出一种简化粒子群(PSO)算法优化改进OIF-Elman神经网络(PSO-IOIF-Elman)功放行为模型。该模型同时考虑小信号和大信号对功放记忆非线性的影响,结合AM-AM和AM-PM失真把OIFElman神经网络的自反馈系数用归一化后的输入输出电压表示。采用简化PSO优化算法,避免陷入局部最优,用粗糙集理论对模型预测值进行修正与补偿,提高预测精度。通过Matlab仿真比较,该模型训练误差减小9.53%,收敛速度提高11.31%,进而验证了建模方法的有效性和可靠性。     

基于吸引排斥机制的粒子群优化算法

针对标准粒子群优化算法在处理复杂函数优化问题时容易陷入局部最优、收敛精度低的缺点,提出了一种改进的PSO算法,该算法把生物学中的吸引排斥思想引入到PSO算法中,充分利用粒子间的相互影响,修正了其速度更新公式,从而维持了群体的多样性,增强了粒子跳出局部最优解的能力。实验仿真结果表明,改进的PSO算法提高了进化后期的收敛速度,有效避免了PSO算法的早熟收敛问题,而且具有较高的收敛精度。     

基于改进引力搜索算法的桁架结构优化设计

引力搜索算法是近几年提出的较有竞争力的群智能优化算法,然而,标准引力搜索算法存在后期收敛速度慢的缺点。为有效利用优化算法来解决结构优化的问题,提出一种改进的引力搜索算法(improved gravitational search algorithm,IGSA)。通过引入Logistic映射,使GSA初始种群遍历整个搜索空间,提高算法找出最优解的可能性。通过引入粒子群算法(particle swarm optimization,PSO)的信息交互机制,利用个体粒子历史最佳位置和种群历史最佳位置动态调整粒子的速度和位置,使个体粒子更快地向适应度值更高的位置移动,使算法搜索能力加强。对6个经典测试函数进行寻优,结果表明改进后算法收敛速度快,收敛精度高,稳定性较佳,跳出局部最佳解的能力较强。用IGSA和GSA对72杆空间桁架进行尺寸优化,与其他算法相比,结果表明IGSA得到最优值的迭代次数明显减少,得到的最优解明显优于通用算法。     

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.     

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。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

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.