国防工程震害风险分析体系的ISM研究

为探究国防工程震害风险体系内部规律和结构元素之间的相互关系,设计和实现了一种基于解释结构模型的国防工程震害风险分析结构模型组件。遵循解释结构模型的本质思想和工作程序,在确定国防工程震害风险分析体系逻辑关系的基础上,给出国防工程震害风险解释结构模型组件方案,研制基于窗体界面线程设计的国防工程震害风险分析解释结构模型算法组件,求解系统可达矩阵,构建多层递阶的国防工程震害风险结构模型。模型解释了国防工程震害风险体系的神经支撑结构、关键特征等层次关系和功能映射,风险评价的立足点在于“国防工程整体性工程风险”,关键特征包括区域地质环境变异元素、国防工程毁伤评估、国防工程主体结构风险等元素,为研究、探索、完善国防工程震害风险系统设计方法提供科学依据。     

工程围岩结构风险评估的物元模型组件研究

为科学、准确、快速、智能化评价工程围岩结构状态,设计和实现了一种基于可拓物元理论的围岩结构风险评估模型组件。从工程围岩结构风险的可拓物元评估模式出发,建立其物元结构和风险域空间,集成变异系数和熵值信息的组合赋权方法,改进工程围岩结构风险评估模型和风险偏向判决;遵循可拓物元模型的本质思想和关键概念,着眼模型智能化执行和用户可视化操作需求,提出了工程围岩结构风险评估组件的设计方案、体系结构和功能构成,研制了基于窗体界面线程设计的工程围岩结构风险物元算法组件。案例表明,组件式物元模型交互性良好,为有效分析工程围岩结构风险的本质问题提供了模型支持和实验工具。     

基于改进证据理论和神经网络的故障诊断模型*

针对单一故障诊断方法精度低的问题,提出了一种基于D-S证据理论和神经网络相融合的决策层融合故障诊断模型。该方法利用证据理论来处理不精确的、模糊的信息,用神经网络来处理证据理论中的基本可信度分配问题。由于证据理论合成公式无法处理高冲突的证据,提出了一种改进的基于冲突焦元的证据合成规则。该模型在降低决策不确定性的同时大大提高了诊断的精度。最后通过发动机故障诊断实例验证了该模型的有效性。     

基于D-S理论的认知无线电频谱感知算法

针对目前的认知无线电频谱感知数据融合判决规则忽略了各感知节点所处环境差异这一问题,研究了一种基于信任度的多节点频谱感知算法,将D-S证据理论引入判决融合中,通过Matlab仿真验证了该算法的性能相比于原有的频谱感知数据融合算法有了很大的提高。     

D-S证据理论中一种新的冲突证据融合方法

针对D-S证据理论在融合高度冲突的证据时可能导致与直观结果相悖的问题,通过分析现有的几种冲突证据融合方法,提出了一种有效处理冲突证据的融合方法。该方法综合了模型修正和规则修正这两类方法的优点。首先基于冲突系数矩阵计算证据的可信度,并以此作为折扣因子来修正证据结构,然后基于局部冲突、局部分配原则确定证据合成时的冲突分配空间和分配权重。实验结果表明,该方法对合理的合成方向具有较快的收敛速度,同时降低了决策风险。     

煤矿带式输送机健康诊断方法

针对基于多传感器信息融合的煤矿带式输送机健康诊断方法运用D-S证据理论在处理冲突证据时失效的问题,提出了一种基于模糊证据理论的带式输送机健康诊断方法。该方法首先利用多种传感器采集带式输送机信息,并根据隶属度函数获取基本概率赋值,从而提取信息特征;然后通过对冲突证据进行修正并应用D-S证据理论的合成规则,实现基于模糊证据理论的信息融合;最后根据决策规则判断带式输送机运行状态。通过实例验证了该方法的有效性。     

基于D-S证据理论的指纹图像分割方法

在对D-S证据理论进行简单分析之后，针对指纹图像提出了一种基于D-S证据理论的图像分割算法．该方法使用方向性和对比度两个信息分别作为两个分类器的特征，并利用模糊规则求出各分类器的基本概率分配函数，最后利用D-S证据理论的合成法则将两个分类器的结果进行融合判决．该方法具有较高的稳健性和精确度，最后给出的实验结果验证了算法的有效性．     

基于加权D-S证据理论的分布式多传感器目标识别

针对分布式多传感器环境下的目标识别问题，提出了一种基于加权D-S证据理论组合规则的决策融合方法。分析了多传感器目标识别系统的信息模型，指出传感器的决策可信度由其被支持度及与目标间的距离确定。将该可信度体现为加权D-S证据理论组合规则中的证据权值，综合考虑传感器支持度及其与目标距离，给出了权值确定方法。仿真实验证明方法提高了融合效率，可较快完成识别任务。     

D-S证据理论在审计证据融合中的应用研究

古典概率难以解释审计判断的不确定性,而D-S证据理论是进行不确定性推理的有效方法,因此应用D-S证据理论进行审计证据融合的研究。针对审计证据的组合问题,提出了基于三角形模糊隶属度函数的基本概率分配函数计算方法,给出了证据组合结果的判决规则,并通过实例验证了该方法的有效性。     

D-S证据理论在指纹图像分割中的应用研究

有效的指纹分割能够提高特征提取精度和减少后续处理时间,针对这种情况,提出一种基于D-S证据理论的指纹图像分割算法。该算法首先用改进的灰度方差和均值进行初级分割,然后进行平滑;其次使用方向性和对比度两个信息分别作为两个分类器的特征,并利用模糊规则对各分类器的基本概率分配判断,最后利用D-S证据理论的合成法则将两个分类器的结果进行融合判决,实验结果验证了算法的有效性。     

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).