应用OBDD和PSL的航迹规划方法研究

航迹规划是决定无人飞行器飞行航迹优劣的关键环节。由于无人飞行器飞行空域广,态势也较复杂,实际规划中常常面临搜索的状态多、收敛时间慢等问题,这成为无人飞行器执行飞行任务的瓶颈,解决的优化策略包括:缩小问题的状态空间以及根据问题的约束条件,在搜索中剪枝。模型检验的经典OBDD(有序二叉决策图)方法是表示状态和状态迁移的高效率的数据结构方法,可以简化状态系统的表示空间;而PSL是一种重要时序逻辑,利用PSL和一阶逻辑描述无人飞行器航迹规划的领域约束,以期在规划中剪枝搜索状态。在使用上述两种优化策略基础上设计了航迹规划搜索算法,并实现了该算法的规划仿真,仿真结果表明该方法是一种有效可行的航迹规划方法。     

基于本体的领域知识共享研究

提出一和中基于本体实现领域知识共享的方法，对领域知识进行了层次化的表示，并以过程规范语言本体为例进行说明。同时，给出了基于本体的知识推理方法，设计了两种基于本体的应用系统共享领域知识的体系结构。最后，给出了该研究成果在工作流建模中的应用。     

主应力场驱动的复杂薄壁件刚度增强方法

针对传统井字形加强筋等加强方式在复杂薄壁件的刚度增强效果并不总是最优的问题,提出了一种复杂薄壁件的刚度增强方法。探究了基于主应力场模型的王莲筋脉布局的仿生原理,提出了主应力场驱动的复杂薄壁件轻量化刚度增强优化方法。实验结果表明,与井字形加强筋结构相比,结构质量基本相同时,该方法生成的复杂薄壁件的比刚度增大33%。     

PSL: A semantic domain for flow models

Flow models underlie popular programming languages and many graphical behavior specification tools. However, their semantics is typically ambiguous, causing miscommunication between modelers and unexpected implementation results. This article introduces a way to disambiguate common flow modeling constructs, by expressing their semantics as constraints on runtime sequences of behavior execution. It also shows that reduced ambiguity enables more powerful modeling abstractions, such as partial behavior specifications. The runtime representation considered in this paper uses the Process Specification Language (PSL), which is defined in first-order logic, making it amenable to automated reasoning. The activity diagrams of the Unified Modeling Language are used for example flow models.     

PSL602保护重合闸误动作分析

从一次线路重合闸的误动作分析重合闸误动作的原因,并针对断路器防跳回路容易出现的问题,提出有针对性的防范措施。     

基于移动Agent的协同电子商务安全认证机制

如何提供一个协同、开放、灵活并高效的安全服务，是协同电子商务必须解决的一个重要问题，移动Agent为解决这一问题提供了一个新的方法。该文介绍一种基于历史事件的安全认证机制，以期进一步完善协同电子商务中的安全服务问题。     

基于PSL的制造过程信息描述方法研究

为解决企业制造过程信息的描述和交互问题,提出了一种基于可扩展标记语言（XML）的过程描述元模型。在该模型中,定义了基于过程描述语言（PSL）本体的语义映射规则及映射的具体过程,对过程描述语言本体进行了语义分析,实现了对过程信息的语义层次描述;借助可扩展标记语言的语法结构,建立基于可扩展标记语言的过程描述语言核心元素的描述规则．并作为过程信息语法层次描述的统一标准,实现过程信息在语法层次的信息转换。最后,通过具体的可选工艺信息描述实例,验证了该模型及实现方法的有效性和可行性。     

The preparation of concentrates of eicosapentaenoic acid and docosahexaenoic acid by lipase-catalyzed transesterification of fish oil with ethanol

The objective of this study was to investigate the use of lipases as catalysts for producing concentrates of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil as an alternative to conventional chemical procedures. Transesterification of fish oil with ethanol was conducted under anhydrous solvent-free conditions with a stoichiometric amount of ethanol. Among the 17 lipases tested, the results showed that Pseudomonas lipases had the highest activity toward the saturated and monounsaturated fatty acids in the fish oil, much lower activity toward EPA and DHA and, at the same time, good tolerance toward the anhydrous alcoholic conditions. With 10 wt% of lipase, based on weight of the fish oil triacylglycerol substrate (15% EPA and 9% DHA initial content), a 50% conversion into ethyl esters was obtained in 24 h at 20°C, in which time the bulk of the saturated and monounsaturated fatty acids reacted, leaving the long-chain n-3 polyunsaturated fatty acids unreacted in the residual mixture as mono-, di-, and triacylglycerols. This mixture comprised approximately 50% EPA+DHA. Total recovery of DHA and EPA was high, over 80% for DHA and more than 90% for EPA. The observed fatty acid selectivity, favoring DHA as a substrate, was most unusual because most lipases favor EPA.     

X60钢级管线用无缝钢管的研制

从钢种成分、工艺路线、工业性试验等方面论述了X60(PSL1)钢级管线用无缝钢管生产中存在的问题,分析了产生的原因,认为MnNb钢在1050℃以上的温度时,其奥氏体晶粒将出现明显的混晶及粗化现象,将对钢管的综合力学性能,尤其是冲击韧性有不利的影响。将AR轧管机终轧温度控制在1050℃以下是提高该钢种冲击韧性的有效途径。也是用非调质工艺生产X60(PSL1)钢级管线用无缝钢管的关键措施。     

基于PSL的本体交换技术研究及应用

在实践中由于创建本体的工具、理论的不同而产生本体交换的需要，而PSL正是为解决过程应用中本体的交换问题而设计的，这里讨论了PSL本体的结构，并以工艺过程中的毛坯和库存过程中的原材料两个概念为例来说明PSL的本体交换机制。