时间约束的RBAC模型及应用

基于角色的访问控制模(RBAC)自提出以来一直被视为用来进行访问控制的普遍方法。时间约束的RBAC模型是RBAC模型在时间约束上的扩充。描述了时间约束和时间约束模型,重点研究了时间约束模型的系统结构。分析了校园网计费系统的应用需求,设计并实现了基于时间约束机制模型TRBAC的访问控制实例。     

工作流系统中一个基于双权角色的条件化RBAC访问控制模型

传统的RBAC访问控制模型已经不能表达复杂的工作流安全访问控制约束。基于传统的RBAC模型,提出了一个新的基于双权角色的条件化RBAC访问控制模型CRDWR(conditioned RBAC based on double—weighted roles)。阐述了基于动态角色分配的条件化RBAC策略,定义了基于双权角色的工作流系统访问授权新概念,并针对多个角色协同执行任务的序约束问题,给出了基于令牌的序约束算法。该模型能够表达复杂的工作流安全访问控制约束。     

电子政务中的扩展RBAC安全策略研究

通过对基于角色的访问控制模型(RBAC)与其扩展的研究,该文提出了在电子政务系统中适用的强制性的基于时空约束与角色的访问控制模型(MSTRBAC),该模型在RBAC中引入了强制性授权、时间约束与空间约束的手段,具有安全性完备,授权灵活,实现简单的特点。     

协同环境下扩展角色访问控制模型设计与研究

为了解决基于角色的访问控制模型(RBAC)在协同工作方式下与工作流结合的角色冲突问题,降低授权管理的复杂性,降低管理开销.以RBAC为基础,提出了基于扩展角色的访问控制模型(ARBAC),模型中工作流的角色授权同时受时间、行为和环境3个方面约束,提高了协同工作状态下访问控制的安全性,提升协同工作效益.结合实际的协同开发流程,表明了该模型的有效性和可行性.     

具有时空约束的角色访问控制模型

信息技术的高度发展对信息安全提出了新的挑战,经典的基于角色的访问控制（RBAC）中缺乏对时间和空间的约束,使RBAC模型不能适应信息系统新的安全需求。在RBAC的基础上,引入了时空域的定义,对模型中各要素进行了时间和空间约束,提出了具有时空约束的角色访问控制模型（TSRBAC）。形式化地描述了TSRBAC,并定义了时空角色继承和时空职责分离,给出了时空访问控制算法。     

多安全域下访问控制模型研究

提出了一个多安全域下基于角色的访问控制模型（MD-RBAC）,该模型以基于角色的访问控制模型（RBAC）为基础,通过角色映射建立起访问控制要素间的关联,并引入有效性约束和基于有效性约束的边界策略对跨域访问的风险进行识别和防护。最后,将MD-RBAC模型与另一个多域环境下的访问控制模型I-RBAC 2000进行了比较。     

周期时间特性的角色访问控制*

针对传统的RBAC模型不能表达时间特性安全访问控制约束的缺点,提出了一个带有周期时间特性的安全访问控制模型。在传统的RBAC模型的基础上定义了周期时间特性的角色访问控制,分析了模型的一致性状态,讨论了一致性状态维护问题,并针对周期时间约束问题提出的相应算法解决了时间授权约束和会话的状态,极大地提高了系统的访问控制能力。     

数据库管理系统RBAC特性研究

介绍了基于角色的访问控制模型RBAC 2000的基本特征，并从核心RBAC、层次RBAC和约束RBAC等三个方面分析和比较了几个通用数据库管理系统中基于角色的访问控制特性。     

RBAC中基于信任的细粒度访问控制研究

针对传统的角色访问控制模型权限控制粒度较大,提出一种基于信任的细粒度访问控制模型,该模型在RBAC基础上引入授权信任约束,采用了一种基于忠诚度的信任度计算方法,有效地遏制恶意行为,实现细粒度访问控制。该模型不仅具有RBAC模型的所有优点,而且比RBAC模型具有更好的通用性、灵活性和可扩展性。     

RBAC职责分割定义及实现模型分析

访问控制是信息安全领域的重要问题之一;目前,基于角色的访问控制模型(RBAC)已被广泛接受,并成为领域专家学者研究的热点;职责分割(SoD)是RBAC的重要方面,它为增强高层次的组织安全策略提供了强大的机制,RBAC职责分割定义给出了各种职责分割约束的具体内容;针对不同的职责分割需求,各种基于角色的访问控制职责分割约束实现模型不断出现;根据应用系统的实际需求选择合适的访问控制模型必须了解各种模型的特点,该文通过分析RBAC中不同SoD模型的特点,指出其适用范围。     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。