PCC中数组边界检查的优化和生成

PCC的数组边界检查存在着由于无法确定数组下标表达式符号值的范围，而造成拒绝执行一些安全的移动代码等问题。本文给出的一种数组边界检查的优化及生成算法，不仅能够比较好地解决了这一问题，同时还生成了循环不变式注解中的条件谓词。我们设计的编译器——认证编译器——已经实现了这些算法，并完成了从用C编程语言的类型安全子集编写的源程序到携带注解的Intelx86／linux汇编语言程序的编译过程。由于基于语言安全策略系统的证明是建立在携带注解的代码基础之上的，因此该认证编译器中实现的算法在移动代码安全检查中非常有用。     

一个C语言安全子集的可信编译器

以安全关键领域的安全标准为依托、安全相关软件的语言编码和编译要求为指导,进行了以下几方面的研究和探索:首先对形式化验证可信编译技术进行分析研究,特别着重当前广受关注的经过验证的CompCert编译器.然后以我国安全领域C语言安全子集标准《航天型号软件C语言安全子集》为依据构造测试用例、创新测试方法,并以此对CompCert编译器进行测试评估.之后依据测试结果,为CompCert编译器增加未支持的C语言标准特性,裁剪不符合C语言安全子集要求的特性,构建符合C语言安全子集标准的可信编译器.最后的实测结果表明,所实现的编译器符合C语言安全子集标准的要求,且没有降低C代码的执行效率.     

基于提示的移动代码安全检查

基于语言内部安全机制能够有效地保证移动代码的安全执行，其思想是要在移动代码中附加详细且足够的满足安全策略检查的注解信息．基于提示的移动代码的安全检查，克服了目前PCC存在的验证条件必须回送和证明长度过于庞大等缺陷，从而获得了更佳的代码安全检查性能．     

一种用于Java虚拟机的类型化低级语言

为了能够减小运算系统的需信任计算基础、描述较小粒度的安全策略，目前的研究倾向于从程序设计语言和编译器入手来提高软件的安全性．基于以上研究背景设计了一种类型化的低级语言TLL,TLL是一种为Java虚拟机即时编译器设计的类型安全中间语言，以构造一个具有更小需信任计算基础的Java虚拟机系统为目的．TLL的类型系统基于多态的类型化λ演算，它具有丰富的表现力且能够编码各种高级语言的抽象．基于TLL的一个虚拟机原型系统已经实现，它可以作为实现一个高安全且面向多种源语言的运行时系统的起点．     

应用安全平台体系中安全策略模型的研究

在分布式系统中,安全策略的管理是很重要的,为了对分布式系统中的安全策略方便地进行管理,并且可以适应不同类型的分布式认证系统,该文通过对RBAC96模型的研究,给出了通过结构化的语言(XML)来描述应用安全平台体系中的安全策略模型和一个实例。     

可信编译器L2C的核心翻译步骤及其设计与实现

同步数据流语言（如Lustre）近年来在航空、高铁、核电等安全攸关领域得到广泛应用.这些领域对相关开发工具本身的安全性有着相当高的要求.为尽力解决好”误编译”问题,近期人们借助reliable-by-construction辅助定理证明器实现常规命令式语言编译器的构造和验证取得了很大的成功,如CompCert C编译器.L2C是基于这种方法开发的可信编译器,它以扩展的Lustre语言为源语言,以Clight （CompCert中的C语言子集）为目标语言.就我们所知,L2C是同类工作中唯一面向实际工业应用的同步数据流语言编译器.本文重点介绍L2C编译器的核心翻译步骤及其设计与实现过程中考虑的主要问题和相关经验.     

浅谈基于GCC的C++静态分析器的开发应用

目前,最主流的开发语言之一就是C++,越来越多的工具都使用C++语言来开发了。因为C++具有高效等特性,所以得到了很广泛的运用。但是不可避免的,在开发软件程序方面,它也存在着一些缺陷。因此,基于开源编译器GCC的C++静态分析器就被开发出来了,可以审查代码,发现缺陷,保证代码的安全和可靠。本文通过对C++静态分析器的C++的语言的缺陷、检查规则以及编译器的内容进行阐述,综合讲解了其开发与应用。     

TC和VC编译器下典型“不兼容”C程序分析

TC和VC是两种常见的C程序编译器。但有时相同的C源程序代码在TC和VC环境下却可能产生不同的运行结果。文中讨论了几类典型不"兼容"的C程序案例,如特殊字符输出、结构类型内存分配等,给出了程序在不同编译器下的运行情况,并分析其原因。     

同步数据流语言可信编译器Vélus与L2C的比较

同步数据流语言（如Lustre、Signal）在航空、高铁、核电等安全关键领域得到广泛应用.例如,适合这些领域实时控制系统建模和开发的Scade工具就是基于一种类Lustre语言.这类语言相关开发工具,特别是编译器的安全性问题也自然受到高度关注.近年来,基于形式化验证实现可信编译器构造成为程序设计语言领域的研究焦点之一,也取得了瞩目的成果,如CompCert项目实现了产品级的可信C编译器.同样,人们也采用这种方法开展了同步数据流语言可信编译器的研发工作.主要关注从事这一工作的两个长线项目,二者均研发面向基于Lustre的同步数据流语言编译器,分别以Vélus和L2C代称.对Vélus和L2C从多个重要的角度进行较为深入的分析与比较.     

MATLAB 与STM32 CubeMX联合的嵌入式开发方法

利用专门的软件STM32CubeMX与 MATLAB进行嵌入式建模与仿真,仿真成功后,在编译器中将其翻译为高效的 MDK C语言代码,大大提高了嵌入式程序的开发效率,缩短了开发周期,并且可以同时利用 MATLAB的代码优化工具箱,提高代码质量。实验结果表明,利用 MATLAB与STM32CubeMX生成的代码在目标系统中运行良好,在设计效率和易维护性方面优于手工编写的代码。     

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.