盲环境下的数字图像可信性评估模型研究

随着各种数字图像处理软件和信息隐藏软件的涌现,数字图像正面临"信任危机".文中从可信的角度考虑数字图像的安全问题,提出盲环境下数字图像可信性评估的概念.文中提出了两类可信性评估模型:可信性判断模型和可信性度量模型.可信性判断模型在数字图像取证技术的基础上,围绕数字图像的不同生命阶段,判断数字图像是否可信.可信性度量模型分为可信性综合度量模型和可信性历史度量模型两种.文中设计了一种基于隐马尔可夫(HMM)的历史度量模型和一种基于模糊层次分析法的综合度量模型.在所设计模型的基础上,文中进一步研究了盲环境下数字图像可信性评估体系.文中最后通过实验结果验证了所提出的数字图像可信性综合度量模型的有效性.     

基于鉴别的等级制可信MAS的研究与设计

可信性问题是限制MAS技术走向成熟的关键问题之一.基于MA间的鉴别,提出了一种等级制可信MAS.论述了基于科层制思想的等级制可信MAS模型;详细论述了SA间以及SA与TA间的鉴别构建等级制可信MAS的过程;给出基于等级制可信MAS的IDS原型.分析表明,等级制可信MAS能够有效解决MAS的可信性问题,有利于促进MAS的广泛应用.     

基于FAHP和FMCDM构建软件可信性评估模型*

结合软件可信性评估的特点及模糊理论的最新进展,提出一种基于模糊层次分析法和模糊多指标决策理论的评估模型。首先针对软件可信性没有一致定义的现状,提出了相对可信性的概念;接着基于模糊数理论,用三角模糊数表示专家评估中语言变量的主观性和模糊性,结合专家给出的模糊指标权重及待评软件可信等级的模糊评价,得到软件可信性的集成模糊评价;最后,将该模型应用到国内某汽车制造企业整车产品开发项目管理软件评估中,实例说明软件可信性评估的具体过程,结果验证了该模型的实效性。     

基于云模型的可信性评估模型*

软件应用领域极度扩展,促使软件可信问题被高度重视,但量化的软件可信性评估却是可信问题研究的难点。针对软件可信性量化问题,提出了基于云模型的可信性评估模型。以REST表述性状态转移超媒体分布式架构为背景,根据云模型理论定义了其组成构件的信任云以及系统综合信任云,用于评估构件的可信性和系统的可信性。从四个层面,探讨软件可信问题,以可信基础参数获取作为最底层输入,进而生成云模型,合并云模型,最终进入可信评估应用层面。实验结果表明,基于云模型的可信性评估模型是有效实用的,在可信度的不确定性方面增加了评估的灵活性。     

基于双重完整性的可信证明模型

传统可信远程证明方法对于动态证明问题描述不足,且在可信证明过程中,证明主/客体交互行为对于可信性的影响缺乏理论依据。为此,提出一种基于证明主/客体双重完整性的可信证明模型,在该模型中引入可信性概念,定义可信属性及可信状态的建立规则,根据该模型设计可信证明系统,并分析主/客体不同完整性的证明方法。     

一种基于信任机制的网构软件的构件选择方法研究

目前网构软件成为一种新的软件形态,如何选择可信构件来构造网构软件,并使其具有尽可能高的用户信赖度,已成为亟待解决的问题。提出了一种基于信任机制的构件选择模型,它运用历史交互构件软件的可信性评价、朋友推荐及构件声誉来计算构件的各项描述的可信性,从而选择可信构件。并提出了一种基于以上可信构件选择模型的构件选择方法,最后通过实验验证了该方法的可行性和有效性。     

一种Web服务组合的可信评估方法

软件可信性日益成为软件工程研究中的热点问题,作为软件资源主要形态的Web服务的可信性也受到了越 来越多的关注。目前对于Web服务可信性的研究主要集中在单一服务QoS属性的可信评价,而针对服务组合的可信 性研究较少。提出了一种通用的原子服务可信评佑模型,并结合原子服务在服务组合执行时的权重,给出了一种基于 结构分析的服务组合可信性的评估方法。最后,结合网络购物实例描述了服务组合可信性评估方法的实验过程。     

一种基于测试数据和D-S证据理论的可信性度量模型

针对软件可信性评估模型客观性不强的问题,提出了基于测试过程数据的软件可信性度量模型。该模型根据软件测试过程和能力成熟度模型CMM模型选取软件测试过程中的关键可信属性,利用软件测试中的过程数据作为可信证据,通过测试过程数据进行可信属性的定量度量,最后,将这些分散的可信指标通过D-S证据理论进行融合得到软件的可信性。实例表明,该度量模型在软件可信性评估中是有效的。     

基于证据推理的嵌入式软件可信性评估方法*

传统的可信性评估模型通常使用软件度量医逻辑验证方法进行定量估计,在应用于体系结构复杂、可信度要求较高的嵌入式软件时,依然存在可信需求不明确、专家主观认知无法集成等问题.在分析嵌入式软件可信需求的基础上,构建一种基于证据推理方法的嵌入式软件可信性评估模型,并定义证据合成算子和效用估算模型以实现多样化可信证据的一致融合与量化.仿真实验验证了该模型在解决嵌入式软件可信性评估问题时的合理性与有效性.     

基于多维质量属性偏好的可信服务选择

现有的可信服务选择方法将信任值表示为单一的实数,并依据信任值对候选服务进行排序,不能充分体现服务可信性的特征和用户偏好.在传统服务质量模型的基础上引入可信属性构建多维服务质量模型,并阐述信任值的计算方法.在此基础上提出一种层次分析法和偏好排序组织法结合的服务选择方法,其中,层次分析法用于计算基于用户偏好的属性权重值,偏好排序组织法用于对候选服务进行排序.实验表明该方法可以有效地表达用户对于多维服务质量属性的偏好,提高服务排序和服务选择的可信性.     

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).