基于代理部分盲签名的离线电子现金方案

代理盲签名结合了代理签名和盲签名的优点,在电子现金中广泛应用。但在大多数基于代理盲签名的电子现金系统中,电子现金的金额是不可见,而且恶意用户能伪造跟踪信息,因此不满足实用性和不可重复花费性。本文提出一个基于双线性对代理部分盲签名方案,其安全性可规约为Computational Diffie-Hellman(CDH)问题。在代理部分盲签名和知识签名的基础上,提出一个安全的电子现金方案,防止恶意用户伪造跟踪信息,实现电子现金重复花费检测。分析结果表明,该方案满足不可重复花费性、不可伪造性、匿名性和实用性。     

一个多银行参与的可传递的公平电子现金系统

基于群盲签名的思想,提出一个具有多个银行参与发行的、可传递的、公平的、离线电子现金系统(FTOLC).多个银行参与电子现金的发行,并能够保证发币银行的匿名性,必要时可以由中央银行识别出发币银行的身份.同时,用户在正常情况下可以匿名地消费,而在特定条件(如法律强制要求)下,可以通过可信第三方撤消用户的匿名性.首次在信息量不增加的情况下,实现了公平离线电子现金的可传递性.     

一种新的基于ACJT群签名的电子现金方案*

针对目前电子现金的两大主要的安全威胁--重复花费和敲诈提出了一种新的电子现金方案,不仅实现了可撤销匿名性,能有效地防止重复花费,还在取款协议中加入了防止敲诈的手段,因此能满足多方面的安全要求.该方案基于目前公认效率较高的ACJT群签名实现,具有较高的效率.     

基于椭圆曲线的离线公平可分电子现金系统

基于椭圆曲线离散对数问题和Brands的受限盲签名技术,提出了一个基于椭圆曲线的离线公平可分电子现金多统.系统具有匿名性,能有效保护消费者的隐私,在必要时可撤销匿名性以打击犯罪,交易过程的公平性通过引入可信第三方实现,防止交易中的某一方受到欺诈,但可信任的第三方只在注册阶段和出现争议时才在线.引入可兑币实现电子现金的可分性,可用于多次精确支竹.该电子现金还具有防止超额支付,重复花费的特点.分析表明,方案是安全的、高效的.     

一种可提升用户匿名性的离线电子支付方案

提出一种新的具有可提升用户匿名性的离线电子支付方案。用户都可以根据交易时间、计算及通信开销,选择提高其匿名性,还可以从SA代理那里获取面额较小的电子现金用于支付,解决了电子现金的“找零”问题。与其他支付协议相比,该协议还可以恢复因计算机崩溃或文件误删而丢失的电子现金,而且能够防止重复花费、窃听、篡改和高手段的犯罪。     

高效的离线电子现金方案

电子现金本质上是一串容易被复制的比特序列,如何在保护合法用户匿名性的前提下有效地防止其被重复花费是电子现金研究的关键。提出了一种新的基于RSA盲签名的离线电子现金方案,采用双密钥对称加密,将用户账号信息嵌入其中,从而保证合法花费一次用户的匿名性,也能够以极大的概率找出重复使用同一笔电子现金的用户。对分割选择（cutandchoose）机制进行了改进,降低了计算复杂度。最后,对方案的公平性和安全性进行了分析。     

可三方使用的电子现金*

提出了可三方使用的电子现金方案,使用该方案,用户U在某地提取电子现金时,Alice和Bob也可以在异地通过开放网路下载并且使用这些电子现金,用户U也可使用.     

一个新的离线公平可分电子现金支付系统

电子现金的可分性能够实现电子现金的精确花费,可分性的电子现金大多基于二叉树的思想构造,然而很少的电子现金协议同时具有可分性和公平性的特点。基于二叉树、盲签名和简单的秘密共享等思想,构造了一个公平可分的电子现金方案。     

盲签名在电子现金中的应用

该文根据近年来国内外关于盲签名的研究背景及进展,阐述了盲签名的概念和基本思想,分析了两种电子现金实现方案,着重探讨了盲签名在电子现金取款协议中的应用。同时给出了检测重复花费电子现金的方法。     

一种具有可恢复性的离线电子支付方案

提出一种具有可恢复性的离线电子支付方案 .用户可以借助可信第三方 (简称 TTP)恢复因计算机崩溃或电子钱包丢失等原因而丢失的电子现金 ,本方案还能够有效防止重复花费、窃听、篡改和高手段的犯罪     

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.