Complexity of synthesis of composite service with correctness guarantee

How to compose existing web services automatically and to guarantee the correctness of the design (e.g. temporal constraints specified by temporal logic LTL, CTL or CTL*) is an important and challenging problem in web services. Most existing approaches use the process in conventional software development of design, verification, analysis and correction to guarantee the correctness of composite services, which makes the composition process both complex and time-consuming. In this paper, we focus on the synthesis problem of composite service; that is, for a given set of services and correctness constraint specified by CTL or CTL* formula, a composite service is automatically constructed which guarantees that the correctness is ensured. We prove that the synthesis problem for CTL and CTL* are complete for EXPTIME and 2EXPTIME, respectively. Moreover, for the case of synthesis failure, we discuss the problem of how to disable outputs of environment (i.e. users or services) reasonably to make synthesis successful, which are also proved complete for EXPTIME and 2EXPTIME for CTL and CTL*, respectively.     

A novel logic-based automatic approach to constructing compliant security policies

It is significant to automatically detect and resolve the incompliance in security policy.Most existing works in this field focus on compliance verification,and few of them provide approaches to automatically correct the incompliant security policies.This paper proposes a novel approach to automatically transform a given security policy into a compliant one.Given security policy Π and delegation policy M declared by logic programs,the approach automatically rewrites Π into a new one ΠM which is compliant with M and is readable by the humans.We prove that the algorithm is sound and complete under noninterference assumption.Formally,we show that the security policy query evaluation algorithm with conflict and unsettlement resolution still works very well on ΠM.The approach is automatic,so it doesn’t require a administrator with excess abilities.In this sense,our proposal can help us to save much manpower resource in security management and improves the security assurance abilities.     

基于虚拟可重构平台的时序电路演化设计

目前,电路进化设计是演化硬件研究的主要方向之一。而时序电路由于存在反馈环不便于进行电路描述和软件仿真。文中对时序电路的演化设计方法进行了改进,提出了专门针对时序电路演化的虚拟可重构平台,建立起电路编码与HDL代码的映射关系。应用TEXTIO和MATLAB来辅助仿真测试过程,使测试向量数量巨大、难以处理的问题得到很好地解决。最后调用ModelSim完成了FSM的演化实验。实验结果验证了基于此平台演化时序电路的可行性和有效性。     

Kaman协议的形式化验证

Kaman协议是移动Ad Hoc网络安全认证机制,然而,协议设计者未对该协议的安全性作严格的形式化分析。协议复合逻辑PCL是验证协议安全属性的形式化方法,PCL逻辑能够简化协议安全分析过程。本文在协议复合逻辑PCL中描述Kaman协议并分析Kaman协议的安全属性,证明Kaman协议能够实现其安全目标。     

一种用于指针程序的形状分析方法

指针程序的分析一直是研究热点。本文提出一种基于形状图逻辑的形状分析方法,其中形状分析采用形状图来表达程序中指针的指向和相等关系,并用形状图逻辑来进行推理。形状图逻辑是一种把形状图看成有关指针的断言,并在此基础上对Hoare逻辑进行扩展而得到的程序逻辑。首先介绍所提出的形状图和形状图逻辑;然后在此基础之上,设计一种基于形状图逻辑的形状分析方法。     

编程思维训练通用模型研究与实现

程序设计类课程是培养学生逻辑编程能力的基本课程之一,但目前普遍反映出学生对此类课程的学习兴趣不浓,对程序设计与实现的逻辑思维混乱不清,学习效果较差。如何脱离编程语言本身,运用模拟现实生活的思维训练模型来形象地展示编程的原理与逻辑流程,以提高学生对程序设计的逻辑思维能力和学习效果是本文研究的重点。     

基于智能终端的移动MIS基础平台设计与研究

在综述目前广泛研究的智能终端模式的基础上,提出了一种新的基于智能终端和面向服务体系结构的移动MIS基础平台。该平台基于智能客户端技术和元数据业务模型,可以实现移动公办与后台管理信息系统的结合。详细阐述了移动MIS基础平台的设计、实现及其优点。     

基于逻辑器件的可编程增益放大器设计

本文介绍了可编程增益放大器设计的方法。它主要由控制电路、放大电路、显示电路三大模块组成。该系统性能好、成本低、工作可靠,具有一定的工程应用价值,经测试表明,该设计基本上达到了设计的要求。