果蝇优化算法融合SVM的风机叶片损伤识别研究

为提高风机叶片裂纹损伤和边缘损伤识别的准确率,提出使用果蝇优化(FOA)算法和支持向量机(SVM)相结合的方法。使用硬件系统采集两类损伤故障的声发射信号,然后对信号进行小波处理,提取能量特征,根据能量特征信息,建立支持向量机模型,测试其准确率;采用果蝇优化算法优化支持向量机参数,使模型损伤识别更准确,并将优化后模型识别结果与粒子群优化(PSO)算法优化支持向量机后的识别结果相比较。仿真结果表明,使用果蝇优化算法优化后的支持向量机模型的识别精度更高,能够准确地实现对风机叶片损伤的识别。     

基于SVM的视频关键帧语义检索系统

为缩小"语义鸿沟",探讨了将支持向量机(SVM)应用于视频语义检索,提出了利用多变量支持向量机回归方法(SVR)进行语义自动标注,再将SVM分类应用于关键帧的语义检索的反馈中,改进了传统的SVM反馈方法.一方面记忆并累加样本集,优化负例选择,平衡正负样本数目,使训练集样本保持动态增长的平衡状态;另一方面,保存每次满意查询的SVM模型,使本次的反馈信息得以继续使用,从而建立SVM反馈的长期记忆机制.实验结果表明,与基于内容的SVM反馈检索相比,改进后的基于SVM反馈的视频语义关键帧检索的准确率和检索效率都有所提高.     

深度优先搜索的支持向量机参数优化算法

研究支持向量机参数优化问题,由于算法要求准确选择SVM参数,支持向量机在处理大样本数据集时和最优模型参数确定时,消耗的时间长、占有内存大,易获得局部最优解的难题.为了解决支持向量机存在的不足,采用深度优先搜索算法对其参数优化机机制进行改进.将向量机参数优化视成一个组合优化问题,将支持向量机模型的分类误差作为优化目标函数,采用深度优先算法对其进行求解,最后将模型应用于3个标准分类数据集.仿真结果表明,优化参数后的支持向量机加快模型的训练速度度,提高了分类的准确率,很好的解决了支持向量机参数优化难题.     

基于改进粒子群优化的SVM故障诊断方法

针对支持向量机(SVM)分类模型参数选取困难的问题,提出基于遗传免疫的改进粒子群优化算法,克服传统粒子群算法前期收敛快、后期易陷入局部最优的缺陷。将该算法与优化支持向量机分类模型相结合,建立基于遗传免疫粒子群和支持向量机的诊断模型,并用于轴承故障诊断中。结果表明,基于遗传免疫粒子群算法优化的SVM可实现对SVM分类模型参数的自动优化,并能提高SVM分类模型的故障诊断精度,对分散程度较大、聚类性较差的故障样本分类有较强的适用性。     

基于混合粒子群优化SVM算法的红斑鳞状皮肤病诊断

红斑鳞状皮肤病的诊断是皮肤病科的一个难题,针对这一问题,提出一种基于混合粒子群的支持向量机(SVM)模型HAPSO-SVM来提高红斑鳞状皮肤病的诊断精度。模型考虑了特征选择机制和参数优化两者对SVM模型起着同等重要的作用,使用自适应的混合粒子群算法(HAPSO)同步实现特征选择机制和SVM的参数寻优,同时设计的线性加权多目标函数综合考虑了分类准确率和支持向量个数,从而提高了算法的准确率和效率。结果表明,提出的模型不仅获得了较少的支持向量个数,找出了红斑鳞状皮肤病紧密相关的特征,并且得到了很高的分类准确率,是一种有效的红斑鳞状皮肤病诊断模型。     

基于离散微粒群优化算法的SVM参数选择

支持向量机(SVM)的学习性能和泛化能力主要取决于参数选择,然而传统的优化算法难以解决此问题。文中通过支持向量的个数建立优化目标函数,采用微粒群优化(PSO)算法对其优化,寻找最优参数。PSO是一种新兴的基于群体智慧的进化算法。实验表明,微粒群优化算法是支持向量机参数选择的有效方法。     

基于粒子群优化支持向量机的煤矿水位预测模型

支持向量机算法(SVM)具有可靠的全局最优性和良好的泛化能力,适用于有限样本的学习,而该算法的成功与否很大程度上取决于其参数的选择,而常规经验选取方法往往不能获得满意效果。利用粒子群算法(PSO)随机搜索策略对支持向量机参数进行优选,建立基于粒子群算法参数优化的支持向量机模型(PSO-SVM)。仿真结果表明,该优化模型比传统的人工神经网络(BP)模拟效果要好,在拟合精度方面有很大的提高,且具有较好的泛化能力。     

基于CMA—ES算法的支持向量机模型选择

研究模型选择对支持向量机(SVM)的泛化性能有着重要影响。针对传统梯度算法对初始值敏感及网格搜索法计算复杂的缺点,为了提高全面优化能力和分类精度,提出了一种基于协方差矩阵自适应进化策略(CMA-ES)的支持向量机(SVM)模型优化算法,通过对SVM泛化性能界(Bounds on Generalization Performance)的优化求解,实现了基于CMA-ES算法的SVM模型选择。在标准数据集上的实验结果表明:相比遗传算法和梯度算法,上述方法能够在较小计算代价下得到更优的超参数,提高支持向量机的预测精度稳定性,尤其适合大样本数据条件下的模型选择。     

PSO-SVM算法在肝脏B超图像识别中的应用

为提高肝脏B超图像的诊断准确率,研究了将粒子群算法(Particle Swarm Optimization,PSO)和支持向量机(Support Vec-tor Machine,SVM)相结合进行肝脏B超图像识别的方法;该方法首先提取肝脏B超图像的空域和频域的纹理特征,然后运用SVM对108幅肝脏B超图像进行分类,利用PSO算法优化SVM的模型参数,最后将该方法与基于网格搜索法优化的SVM和基于BP神经网络的分类方法进行了对比;实验结果表明,在PSO-SVM算法下,所提取的两种纹理特征相结合能够有效地描述肝脏B超图像,基于粒子群优化算法的支持向量机模型具有较高的识别精度,平均分类准确率达94.44%,这就表明PSO-SVM算法适用于对肝脏B超图像的识别。     

一种改进的支持向量机的文本分类算法

在文本分类中,应用支持向量机(SVM)算法能使分类在小样本的条件下具有良好的泛化能力.但支持向量机的参数取值决定了其学习性能和泛化能力.为提高支持向量机算法的性能,提出了一种采用免疫算法对支持向量机参数进行优化的文本分类算法(IA-SVM).算法减少了对支持向量机参数选择的盲目性,提高了SVM的预测精度.实验表明,IA-SVM算法在文本分类问题上明显提高了分类正确牢,学习速度也有提高.     

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。     

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.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).