多级安全性政策的历史敏感性

对安全政策灵活性的支持是现代安全操作系统追求的目标之一,DTOS(distributed trusted operating system)项目提出了安全政策格的思想,为安全政策灵活性的研究提供了一种很好的手段.然而,DTOS项目给出的安全政策的格描述把多级安全性(multi-level security,简称MLS)政策认定为静态安全政策.首先,从理论上构造MLS政策的一个实施策略,说明MLS政策具有历史敏感性,从而具有动态特征,不能简单地作为静态安全政策对待.同时,给出所构造的实施策略的实现算法,说明该实施策略与常规实施策略具有相同的复杂度,是一个实用的实施策略.由此证明,可以找到合理、灵活、实用的实施策略,使MLS政策具有历史敏感性,从而证明把MLS政策认定为静态安全政策的不合理性.     

对一类多级安全模型安全性的形式化分析

深入分析了MLS的核心思想,给出了MLS在包含多级客体的系统中的表述形式,分析了安全不变式（invariant）在系统安全定义中的作用．为了保证模型的安全,必须验证模型的不变式满足MLS策略．为了说明不变式验证的重要性,借助Z语言和形式验证工具Z／EVES分析了一个改进的BLP模型——DBLP模型．分析表明,DBLP模型的不变式不满足MLS策略的要求,因此是不安全的．这项研究为分析各种改进BLP模型的安全性提供了理论依据和形式化规范与验证的方法．     

基于轨迹的策略描述和复合

1 引言随着计算机信息系统在众多领域的广泛应用,民用尤其是商用计算机系统安全也逐渐引起人们的重视。在军用计算机系统领域,安全需求相对来讲比较单一和稳定(随着网络应用的发展,军用系统安全需求也有所变化),Bell&LaPadula(BLP)模型描述的多级军事安全(Multilevel Security,MLS)策略体现了军用系统的主要安全需求。但在民用领域很难找到这样统一的安全需求,与军用系统相比,民用系统安     

网络和信息安全要走产业化之路

近年来,我国信息化进程不断推进,信息系统在政府和大型行业、企业组织中得到了真正而广泛的应用.但与此同时,信息系统所暴露出的安全隐患也越来越引起人们的重视,信息系统安全管理已成为政府、行业、企业关注的问题.如何规范日趋复杂的信息系统的安全保障体系建设,以及如何进行复杂信息系统的安全评估是信息化进程中所面临的巨大挑战.重要信息系统使用单位应根据其信息化建设工作的重要程度和自身安全需求,确定安全等级,选择符合该级别要求的安全产品,并按照相关建设和管理的标准、规范进行安全建设和安全管理已成为行业共识.     

网络经济行为的安全问题(下)

网络信息系统安全是当前建设的重点 最近几年在国内信息安全专家的共同努力下,升华了信息系统安全概念,开始重视网络系统的安全,对计算机病毒与黑客及其非法入侵安全防范提高了认识,并开始实施安全建设,并作为当前的建设重点,应当重视综合效益。 信息安全与信息系统的安全,就其职责来说,主要是国家、行业和企业的技术管理干部和工程师的事情,信息和信息系统安全重视的焦点在信息加密、防病毒和防黑客等操作层面上的微观安全。虽然信息安全和信息系统安全也应当引起国家领导人、行业主管部门和企业领导的重视,但它不     

基于可信级别的多级安全策略及其状态机模型

虽然MLS(multilevel security)被广泛应用于各种安全系统,但是它不能实现信道控制等重要的安全策略.将可信级别的概念引入到MLS中,使其可以方便地实现各种信道控制策略.建立了一个实现这种基于可信级别的多级安全策略的访问控制状态机模型,并证明其对定义的策略是安全的,而且可以实现所有静态信息流策略.另外,还扩展了该模型,使其可以支持存储对象安全属性的动态改变.该模型克服了MLS不能解决安全降级问题以及不考虑完整性的缺点,同时又保留了传统分级策略模型易理解、易使用的优点.     

试析环境监测信息系统安全及防御

信息化建设在环境监测行业中日渐成熟,对于该行业的稳步提升有着不可或缺的作用,然而由于该行业信息化建设处于起步阶段,尤其是在应用的信息系统在安全问题上还需强化,基于目前现状,列举环境监测领域信息系统出现的一些突出问题,并对其中的原因进行分析,同时提出了环境监测信息系统安全问题的防御措施。     

建立医疗保险信息安全体系的研究和实践

研究了在上海医疗保险信息系统这样重要信息系统建立信息安全体系的方法,探索了适合我国国情和行业特点的信息安全管理方法和标准,对信息安全标准本地化进行了探索和实践,为建立我国的信息安全管理标准提供了参考。     

浅析医院信息系统的安全问题

现如今我国的医院信息系统还存在着很多漏洞,如何才能保证医院信息系统的安全成为一大问题.要科学有效的提出应对措施,改善医院信息系统的安全问题,使医院信息系统更好的服务于医务行业.     

基于多策略的区域边界访问控制模型研究

目前区域边界的访问控制是信息安全领域的重要问题.而传统的MLS( Multilevel Security)策略模型注重机密性保护,缺乏完整性保护,无法实施安全的信道控制策略.从多策略的角度,提出了一种区域边界访问控制模型-MPEBAC( Multiple Policy Enclave Boundary Access Control),以MLS模型为基础、以RBAC模型和DTE模型为伙伴策略,消除了MLS策略模型的缺陷,提高了信道控制策略的安全性,实现了基于角色的自主访问控制和基于安全标记属性的强制访问控制,为等级保护下区域边界网关的设计提供了理论基础.     

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。