一种基于学分制排课系统的Z规格说明

运用形式化方法建模在软件开发过程中可提高目标系统的正确性和可靠性,在此提出了一种利用Z语言进行语义分析的方法。该方法在序列图Z规范的基础上,用属性集表示对象状态,并将序列图的上下文表示为Z形式约束,通过检查上下文约束与对象状态间的一致性对序列图进行语义分析。在此以一个基于学分制的排课系统为例,使用面向对象的形式规格说明语言Z,描述了一个精确、完整的高校排课系统的形式化数学模型。过程显示,该方法具有精确的描述性和很强的抽象性,能为软件系统的开发和验证提供科学的框架。     

特征交互动态检测的形式模型

本文通过对业务在执行过程中,业务逻辑实例与外部实体交互消息的分析,提出一个基于消息序列语义的特征交互形式模型.首先,业务逻辑实例和网络实体被认为交互消息集合的子序列,从业务逻辑实例与外部实体交互消息的语法和语义不同角度出发,分别对不确定性、特征违反类和活锁类等不同类型的特征交互给出具体的动态检测形式模型.并在此基础上进一步讨论:在特性违反类特征交互的动态检测中,若直接使用消息序列检测特征交互将是不充分的,本文在最后给出一种简单的特性违反类特征交互动态检测时的补救方法.     

非对称χ-演算的符号互模拟验证算法

非对称χ-演算是一种移动计算模型.文介绍非对称χ-演算的语法和符号操作语义,给出非对称χ-演算的符号互模拟的验证算法,该算法根据算法输出的谓词等式系,求解最大符号解.并证明算法正确性,这在一定程度上为今后的自动机验证提供了理论基础.     

电子设备结构CAD/CAE模型转换与分析

针对目前电子设备结构CAE建模的现状,本文研究了电子设备CAD/CAE模型的转换技术,开发了电子设备结构综合设计平台CAE模型的转换与分析软件系统.通过对整机振动分析验证了处理方法的正确性及软件系统的有效性.与一般的有限元软件相比,在电子设备结构CA E模型的快速建立、修改和振动分析等方面有突出的特点.     

一种有效的不确定数据流Top-K查询算法

Top-K查询处理是不确定性数据管理中一项重要技术。本文在分析不确定性数据模型和可能世界模型的基础上,定义了不确定数据流元组的查询语义,提出了基于记录向量的Top-K查询算法,该算法根据K值,计算并返回分值最高前K个结果,其查询结果评价综合考虑了查询结果在可能世界语义下的概率大小。实验结果表明,与CSQ和SCSQ算法相比,本算法更具高效性和实用性。     

面向分布式系统访问控制的信任度量化模型

通过引入社会学中信任的研究成果,定义了分布式系统访问控制中信任的具体语义、基本特性与上下文相关属性.针对信任的主观性、模糊性与不确定性,采用模糊数学与概率论相结合的方法,给出了信任的数学定义,建立了包括信任综合评价与信任计算的信任度量化模型.该模型综合了访问控制背景下信任相关的各种因素,符合推荐信任的衰减与增强规律.     

一种基于知网的主观题阅卷算法

通过分析知网中词语表示方法提出了一种新型的义原相似度计算方法进而获得词语相似度的计算公式,以词语相似度计算为基础提出了主观题阅卷算法的设计与实现.实验结果证明,该算法能够较好的评阅学生答案中语义正确的内容,这在提高系统阅卷的正确性方面具有一定的意义.     

基于相关主题模型的程序网络自动构建与分析

程序理解的目的在于获得足够的软件系统信息,以适用于人理解的形式展现出来,辅助开发人员对软件的理解.本文通过使用相关主题模型,为软件系统类层次的代码文件建立程序网络,并可视化展示整个软件系统的相关结构和功能,辅助开发者理解整个程序代码.该技术综合考虑了软件代码中的结构性信息和内容性信息,所建立的程序网络可帮助开发者更好的理解程序的语法依赖关系和语义功能相关关系.实验验证了建立的程序网络具有较好的准确性以及可以为指定的类推荐相关类.     

基于改进Bert-AutoML的电力文本语义识别算法

由于电力调度过程中存在大量重复性电力文本,导致语义识别结果形式与理想形式差距较大。针对该问题,提出了基于改进Bert-AutoML的电力文本语义识别算法。采用基于词块的粒度划分方式,提取电力文本字粒度语义特征。计算语义序列与命名实体数据库中语义的相似度,获取多个对应语义序列,构建电力文本语义识别模型。使用自动机器学习法训练模型文本输入,计算输入向量和电力文本库中向量匹配度。结合字符掩码训练策略,将掩盖的内容与背景相联系,得到最终语义识别结果。实验结果表明,该算法语义识别结果呈现段落-结构形式,排列整齐且简洁,与理想识别结果一致。     

一种面向语义Web服务的软件设计语言和设计方法

在分析已有的面向服务的设计和开发方法的基础上,设计了一种语义编程语言SPL,并基于该语言提出一种面向语义Web服务的软件设计和开发方法,试图提供一种有效的解决方案,用于设计和开发面向语义Web服务的软件系统.结合旅游预订领域的一个实例,讨论了该方法的全过程.还给出了SPL语言和相关语言的比较.该研究对面向语义Web服务的软件分析、设计和开发具有一定的参考作用.     

Heterogeneous Simulation—Mixing Discrete-Event Models with Dataflow

This paper relates to system-level design of signal processing systems, which are often heterogeneous in implementation technologies and design styles. The heterogeneous approach, by combining small, specialized models of computation, achieves generality and also lends itself to automatic synthesis and formal verification. Key to the heterogeneous approach is to define interaction semantics that resolve the ambiguities when different models of computation are brought together. For this purpose, we introduce a tagged signal model as a formal framework within which the models of computation can be precisely described and unambiguously differentiated, and their interactions can be understood. In this paper, we will focus on the interaction between dataflow models, which have partially ordered events, and discrete-event models, with their notion of time that usually defines a total order of events. A variety of interaction semantics, mainly in handling the different notions of time in the two models, are explored to illustrate the subtleties involved. An implementation based on the Ptolemy system from U.C. Berkeley is described and critiqued.     

Analysing Internet Software Retrieval Systems: Modeling and Performance Comparison

Nowadays, there exist web sites that allow users to retrieve and install software in an easy way. The performance of these sites may be poor if they are used in wireless networks; the reason is the inadequate use of the net resources that they need. If these kinds of systems are designed using mobile agent technology the previous problem might be avoided. In this paper, we present a comparison between the performance of a software retrieval system especially designed to be used in a wireless network and the performance of a software retrieval system similar to the well-known Tucows.com web site. In order to compare performance, we make use of a software performance process enriched with formal techniques. The process has as important features that it uses UML as a design notation and it uses stochastic Petri nets as formal model. Petri nets provide a formal semantics for the system and a performance model.     

Invisible formal methods for embedded control systems

Embedded control systems typically comprise continuous control laws combined with discrete mode logic. These systems are modeled using a hybrid automaton formalism, which is obtained by combining the discrete transition system formalism with continuous dynamical systems. This paper develops automated analysis techniques for asserting correctness of hybrid system designs. Our approach is based on symbolic representation of the state space of the system using mathematical formulas in an appropriate logic. Such formulas are manipulated using symbolic theorem proving techniques. It is important that formal analysis should be unobtrusive and acceptable to engineering practice. We motivate a methodology called invisible formal methods that provides a graded sequence of formal analysis technologies ranging from extended typechecking, through approximation and abstraction, to model checking and theorem proving. As an instance of invisible formal methods, we describe techniques to check inductive invariants, or extended types, for hybrid systems and compute discrete finite state abstractions automatically to perform reachability set computation. The abstract system is sound with respect to the formal semantics of hybrid automata. We also discuss techniques for performing analysis on nonstandard semantics of hybrid automata. We also briefly discuss the problem of translating models in Simulink/Stateflow language, which is widely used in practice, into the modeling formalisms, like hybrid automata, for which analysis tools are being developed.     

不确定型模糊Kripke结构的计算树逻辑模型检测

本文研究了不确定型模糊Kripke结构的计算树逻辑的模型检测问题,并说明了该问题可以在对数多形式时间内解决.首先给出了不确定型模糊Kripke结构的定义,引入了模糊计算树逻辑的语法和语义.为了刻画存在量词∃和任意量词∀在不确定型模糊Kripke结构中的两种语义解释,在模糊计算树逻辑语法中引入了路径量词∃_sup,∃_inf和∀_sup,∀_inf,分别用于替换存在量词∃和任意量词∀.其次讨论了基于不确定型模糊Kripke结构的计算树逻辑模型检测算法,特别地对于模糊计算树逻辑公式∃_suppUq,∀_suppUq,∃_infpUq和∀_infpUq分别给出时间复杂度为对数多项式时间的改进算法.     

SDL形式语义定义现状及其改进

ＳＤＬ语言自身的形工化描述对该语言的不断发展,完善将发挥重要的核心,而ＳＤＬ－９２的形式语义已无法分满足应用需要,本文分析了现有形式语义定义的基本方法,指出其存在的主要不足,并针对ＳＤＬ形式语义的定义方法提出一种基于ＳＤＬ未来发展方向的语义义框架。     

Intelligent binding in the engineering of automation systems using ontology and Web services

In an integrated automation system a well-designed data model and computation model are required. For the engineering of such a system one often faces a challenge of finding the suitable computation elements defined in the computation model for the data defined in the data model, especially when the data model and the computation model are complex. In this paper we will use the ontology technology and Web services to address the challenge in an intelligent way. We will present the required ontology model including the formal expression, the binding conditions, the object model, XML representation and the corresponding system architecture for implementation. Evaluation is also given to show the usefulness of the approach.     

UML类模型的VDM++形式化规约

利用目前使用最为广泛的形式化验证语言VDM++在描述系统模型的语法和语义上的精确、一致的特点,结合VDMTOOLS和Rational Rose工具把UML类模型中的各个元素转化成VDM++表示,从而实现对UML类模型中所包含的各个元素进行语法和语义的检查。进一步提高UML的建模质量。     

Modeling Stream-Based Applications Using the SBF Model of Computation

Modeling applications and architectures at various levels of abstraction is becoming more and more an accepted approach in embedded system design. When looking at the modeling of applications in the domain of video, audio, and graphics applications, we notice that they exhibit a high degree of task parallelism and operate on streams of data. Models that we can use to specify such stream-based applications on a high level of abstraction are the dataflow models and process network models. Each of these models has its own merits. Therefore, an alternative approach is to introduce a model of computation that combines the semantics of both models of computation. In this article, we introduce such a model of computation, which we call the Stream-Based Functions (SBF) model of computation and show an example. Furthermore, we discuss the composition and decomposition of SBF objects and put the SBF model of computation in the context of relevant dataflow models and process network models.     

LBCCP:一种符合UNIX语义的文件缓存一致性协议及其证明

机群文件系统是机群操作系统的一个重要组成部分，而具有不同语义的文件系统的性能会有显著的差异。高效的客户端缓存协议是机群文件系统性能的关键问题之一。文章提出了一种新型文件缓存一致性协议，该协议通过扩展POSIX文件锁的API来实现UNIX语义模型，并利用I/O自动机理论证明了协议的正确性，在DCFS(Dawning Cluster Fils System)上实现了这个协议。