TCP协议的安全性和活性验证

网络协议簇中,传输控制协议TCP是最重要的协议之一,提供面向连接的可靠传输服务．采用Promela描述TCP建立连接和可靠数据传输,并用模型检测工具Spin,验证TCP三次握手协议的安全性与可靠数据传输协议活性的属性．     

Model Checking over Paraconsistent Temporal Logic

Classical logic cannot be used to effectively reason about concurrent systems with inconsistencies （inconsistencies often occur, especially in the early stage of the development, when large and complex concurrent systems are developed）. In this paper, we propose the use of a guasi-classical temporal logic （QCTL） for supporting the verification of temporal properties of such systems even where the consistent model is not available. Our models are paraKripke structures （ extended standard Kripke structures）, in which both a formula and its negation are satisfied in a same state, and properties to be verified are expressed by QCTL with paraKripke structures semantics. We introduce a novel notion of paraKripke models, which grasps the paraconsistent character of the entailment relation of QCTL. Furthermore, we explore the methodology of model checking over QCTL, and describe the detailed algorithm of implementing QCTL model checker. In the sequel, a simple example is presented, showing how to exploit the proposed model checking technique to verify the temporal properties of inconsistent concurrent systems.     

高镧稀土添加剂在16Mn钢中的应用

针对高镧稀土添加剂对16Mn钢的夹杂物、力学性能的影响进行分析研究,并与富铈稀土添加剂进行对比.实验表明,高镧稀土添加剂能有效变质16Mn钢中的夹杂物,减少夹杂物的数量,改善钢的力学性能.当La/S(质量比)为2.5时,综合力学性能达到最佳值.高镧稀土添加剂能有效替代富铈稀土添加剂进行稀土钢的开发.     

嵌入式实时软件建模方法研究

随着硬件设备计算能力的迅速提高以及社会需求的不断变化和增长,嵌入式实时软件变得越来越复杂.为了提高系统的安全性和可靠性,将基于UML的建模方法与形式化建模方法相结合,可以为嵌入式实时软件建模和验证提供一种良好的解决方案.采用UML扩展机制,在UML2.0顺序图中加入嵌入式实时软件建模所需的时间特性,并提出一种由UML2.0顺序图构造出时间自动机的方法,为下一步验证奠定理论基础.