MAS交互协议的形式化描述和验证

在MAS的分析与设计中,Agent间的交互协议设计是极其重要的内容.特别是交互协议的正确性、有效性和可验证性尤为关键,因此形式化描述和验证多Agent的交互协议非常有必要.定义了用于描述多Agent基于对话的交互协议的一个演算,该演算是基于进程代数的并且独立于Agent的推理过程.该机制可以实现异构多Agent系统的交互协议验证.通过Agent会话环境的状态和演算的形式语义,可以验证会话协议的一些属性,例如:终止性、是否死锁等.该方法可以有效地解决交互协议的语义验证问题,因为协议的状态和Agent的行为由协议本身定义,并且可以避免基于状态搜索的状态空间爆炸问题.     

移动支付协议PCMS的形式化分析和验证

移动电子商务协议的形式化分析和验证是近年来移动电子商务协议的一个重要研究热点。以一个支付网关为中心的匿名的移动电子商务支付协议PCMS为研究对象,建立了PCMS协议的时间自动机模型,并用计算树逻辑CTL公式描述PCMS协议的部分性质,最后利用模型检测工具UPPAAL对PCMS协议的无死锁、时效性、有效性和钱原子性进行检测验证。验证结果表明,以支付网关为中心的匿名的安全支付协议PCMS满足无死锁、时效性、有效性和钱原子性。     

协议形式描述及验证的时态系统

本文通过对网络协议形式化描述和验证问题的研究,针对网络协议的特性,给出了一种基于时态逻辑的模型系统。用该系统能较为方便地对协议进行形式化的描述,并通过建立演绎系统而进行协议性质的有效验证,最后还对一个简单例子进行描述和验证。     

基于有色Petri网的SPIN协议建模与分析

在无线传感器网络路由协议的研究中,对现有协议的分析和验证具有重要意义.形式化建模是分析验证网络协议的一种有效方法.使用形式化工具有色Petri网对无线传感器网络中的SPIN路由协议进行形式化描述,并使用CPN Tools分析和验证了该协议的活性、可达性、有界性等特性.     

IPv6邻居发现协议的形式化验证

采用模型检查技术,对IPv6的邻居发现协议的属性进行了形式化验证.该协议的模型由目前广泛用于设计和描述通信协议的MSC(message sequence charts)来描述,并通过线性时序逻辑说明该协议的属性.还提出了由MSC模型的线性化自动抽取协议属性的方法.     

优先级顶协议的形式化验证

优先级顶协议是一种优先级驱动的抢占式调度协议,它具有无死锁和单阻塞的性质.Dang Van Hung 和Philip Chan在文献[6]中形式地规范和验证了这两个性质.但他们没有对状态函数HiPripcp明确定义,这使得验证的细节较难理解.为了解决这个问题,提出了一种新的方法来验证优先级顶协议单阻塞的性质.通过时段演算的方法,对优先级顶协议进行了规范,并给出了状态函数HiPripcp的明确定义.根据优先级顶协议的规范,形式地验证了该协议的单阻塞性质.采用的验证方法更少地依赖于HiPripcp,这使得验证的细节更易于理解.此外,提出的验证方法可被应用于实时数据库系统中类似协议的形式化验证.     

安全协议的形式化方法概述

介绍了安全协议的形式化分析思路,阐述了安全协议形式化描述、需求、验证及设计四个方面的研究状况和它们的基本原理,并对常用的几种形式化验证技术的优缺点进行了分析,最后针对形式化技术在该领域的发展前景提出了自己的见解。     

基于ATL的公平交换协议的形式化验证

如何对电子商务协议进行分析与验证一直是研究的热点,基于ATL（交替时态逻辑）对电子商务协议中的公平交换协议（Fair Exchange Protocols）进行形式化分析与验证,并选取了其中的一个电子合同签署协议进行形式化验证。用ATL语言来形式化描述公平交换协议,并使用ATS（Alternating Transition Systems,交替转移系统）来为公平交换协议进行形式化建模,再用形式化验证工具MOCHA对公平交换协议的公平性（Fairness）、及时性（Timeliness）和不可滥用性（Abuse-Freeness）进行有效的验证;对验证结果进行分析与讨论,发现了该协议不满足公平性和不可滥用性,不符合设计的要求。     

基于GSPM的安全协议新鲜性分析

安全协议形式化分析方法通过规范描述和数学推理来检验安全协议是否满足各种安全要求.GSPM是安全协议形式化分析的一般模型.在该模型中加入新鲜性的定义,形式化描述了新鲜性这一特殊的安全性质,扩展了GSPM的适用范围,并通过Andrew Secure RPC协议给出了形式化分析新鲜性的实例研究.     

基于环境敏感互模拟的Kerberos协议形式化分析

进程演算通常用来研究交互式反应系统,其中的互模拟方法是用来形式化验证系统属性的重要途径.首先扩展了进程演算中的Spi演算,并将其应用于形式化描述网络安全协议--Kerberos协议的安全属性.为了验证该协议所声称的安全属性,引入了Spi演算中环境敏感互模拟的方法,即两个系统与环境发生交互过程中是否互模拟.通过采用该互模拟关系对Kerberos协议两个安全属性--可认证性和保密性--的证明,发现其可认证性是可靠的,而保密性存在一个可能的漏洞.最后,指出了基于互模拟的安全协议形式化验证方法今后值得进一步研究的方向.     

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.