空间信息服务链模型的有向图表示及其验证

由于目前通用的Web服务组合语言不适合地理信息处理业务流程的直观表达,且学习成本高,不适合空间信息领域的用户使用,因此建立了一种基于有向图的空间信息服务链模型,并从模型组成元素、约束条件和控制模式3个方面对其进行了详细定义和设计。针对构建的服务链模型,从模型语法正确性、结构正确性和语义正确性3个方面进行研究,通过对空间信息服务链模型结构的分析,结合现有的图规约规则,研究并设计了空间信息服务链模型的语法、结构和语义验证方法,并给出了模型验证方法的具体算法和实现流程。通过具体的案例分析,说明了所提出的算法和设计的实施流程的有效性和可操作性。     

普适环境下一种基于图的可靠服务组合机制

在普适环境下,由于设备、网络环境等的动态性,一些服务的提供者容易脱离当前的计算环境,从而造成服务组合方案失效。针对普适环境的特点,以及可靠服务组合的要求,提出了一种普适环境下基于图的可靠服务组合机制RScMPG,该机制从“预防”和“检测一补偿”的角度出发,在“生成可靠服务组合方案”和“监护服务组合正确执行”两个层面上,提高了服务组合的可靠性。     

Abstract Graph Transformation

Graphs may be used as representations of system states in operational semantics and model checking; in the latter context, they are being investigated as an alternative to bit vectors. The corresponding transitions are obtained as derivations from graph production rules.In this paper we propose an abstraction technique in this framework: the state graphs are contracted by collecting nodes that are sufficiently similar (resulting in smaller states and a finite state space) and the application of the graph production rules is lifted to this abstract level. Since graph abstractions and rule applications can all be computed completely automatically, we believe that this can be the core of a practically feasible technique for software model checking.     

Verification of Random Graph Transformation Systems

In this paper we describe some statistical results obtained by the verification of random graph transformation systems (GTSs). As a verification technique we use over-approximation of GTSs by Petri nets. Properties we want to verify are given by markings of Petri nets. We also use counterexample-guided abstraction refinement approach to refine the obtained approximation. A software tool (Augur) supports the verification procedure. The idea of the paper is to see how many of the generated systems can be successfully verified using this technique.     

统一消息服务技术

随着因特网、有线网、无线网的融合 ,统一信息服务应运而生。用户可以使用电子邮件、传真、语音邮件、手机、可视邮件、电话中的任何一种工具发出信息 ,而接收方则可以在自己方便的任何时刻、任何地点 ,使用电话、电脑、传真、呼机中的任何一种工具连接到系统的服务器 ,并获取所需信息 ,它满足了个人通信服务、个人化信息内容服务和个人化电子商务服务的需要     

浅析面向服务的软件架构之服务

SOA(Service oriented Architecture,面向服务的软件架构)离不开服务,服务是其中的核心理念.因此,本文首先从面向服务的软件架构的概念说起,从多个方面对服务进行了描述说明.     

From UML Models to Graph Transformation Systems

In this paper we present an approach that allows to validate properties of UML models. The approach is based on an integrated semantics for central parts of the UML. We formally cover UML use case, class, object, statechart, collaboration, and sequence diagrams. Additionally full OCL is supported in the common UML fashion. Our semantics is based on the translation of a UML model into a graph transformation system consisting of graph transformation rules and a working graph that represents the system state. By applying the rules on the working graph, the evolution of the modeled system is simulated.     

An Efficient Solution for Model Checking Graph Transformation Systems

This paper presents an efficient solution for modeling checking graph transformation systems. The approach transforms AGG specifications into Bogor models and supports both attributed typed graphs and layered transformations. Resulting models are amenable to check interesting properties expressed as combinations of LTL (Linear Temporal Logic) and graph transformation rules. The first experimental results are encouraging and show that in most cases our proposal improves existing approaches, both in terms of performance and expressiveness.     

Policy Analysis and Verification by Graph Transformation Tools

Policies are used to control the behavior of large-scale systems. After policies are designed and before policies are implemented, it should be possible to analyze the policies and verify that they behave as expected. Graph transformations provide a good method to carry out the analysis and verification because of the intuitive representation of policies and the mature theory. Here, we show how graph transformations can simulate PONDER policies and use the graph tools AGG and GROOVE to do the static and dynamic analysis.     

工作流模型的有向图表示及基于Petri网的验证方法

该文从工作流模型的基本结构出发,描述了模型结构的有向图表达方法与建模方式,提出了一种将有向图转化为Petri网的转换算法,说明Petri网与工作流网的关系,之后运用Petri网的分析技术来验证模型的正确性,为电子政务领域内工作流模型的正确性验证提供了一种解决方案。     

Formal Verification of Object-Oriented Graph Grammars Specifications

Concurrent object-oriented systems are ubiquitous due to the importance of networks and the current demands for modular, reusable, and easy to develop software. However, checking the correctness of such systems is a hard task, mainly due to concurrency and inheritance aspects. In this paper we present an approach to the verification of concurrent object-oriented systems. We use graph grammars equipped with object oriented features (including inheritance and polymorphism) as the specification formalism, and define a translation from such specifications to Promela, the input language of the SPIN model checker.     

SOA中业务服务粒度与流程柔性的关系研究

SOA是以提高流程柔性为基本目标的IT架构方法,业务服务粒度在SOA项目中起着关键的作用,该文研究目的在于解释业务服务粒度与流程柔性间的基本关系。首先分析了SOA环境下业务流程的范围柔性和响应柔性两个关键维度并给出定义;基于服务元素和流程协调的研究给出了这两个维度的量化计算方法;构建了业务服务粒度的分析模型并进行量化分析。结果表明SOA环境下随着业务服务平均粒度的增大,流程的范围柔性将逐渐减小,流程的响应柔性将逐渐增大,而流程的整体柔性度将先逐渐增长,达到一定的程度后再逐渐下降。     

Distributed Graph Traversals by Relabelling Systems with Applications

Graph traversals are in the basis of many distributed algorithms. In this paper, we use graph relabelling systems to encode two basic graph traversals which are the broadcast and the convergecast. This encoding allows us to derive formal, modular and simple encoding for many distributed graph algorithms. We illustrate this method by investigating the distributed computation of a breadth-first spanning tree and the distributed computation of a minimum spanning tree. Our formalism allows to focus on the correctness of a distributed algorithm rather than on the implementation and the communication details.     

Reusable Idioms and Patterns in Graph Transformation Languages

Software engineering tools based on Graph Transformation techniques are becoming available, but their practical applicability is somewhat reduced by the lack of idioms and design patterns. Idioms and design patterns provide prototypical solutions for recurring design problems in software engineering, but their use can be easily extended into software development using graph transformation systems. In this paper we briefly present a simple graph transformation language: GReAT, and show how typical design problems that arise in the context of model transformations can be solved using its constructs. These solutions are similar to software design patterns, and intend to serve as the starting point for a more complete collection.     

LS-SVM算法的改进及其在GIS系统中的应用

本文首先研究了面向服务的体系结构及其在地理信息系统中的应用.而后在参考已有的地理信息系统的SOA架构的基础上,提出了将改进的最小二乘支撑向量回归机应用到该信息系统的统计分析服务器中,给统计分析服务器的设计提供了一种新的思路.     

Modeling and Verifying Graph Transformations in Proof Assistants

This paper takes first steps towards a formalization of graph transformations in a general setting of interactive theorem provers, which will form the basis for proofs of correctness of graph transformation systems. Whereas graph rewriting is usually performed by mapping a pattern graph into a source graph by means of a graph morphism and then carrying out operations on the image node and edge set, this article generalises the notion of pattern graph to path expressions, which are formulae in a fragment of first-order logic. We examine the correspondence with traditional graph rewriting and show that this interpretation is beneficial when formally reasoning about model transformations with the aid of proof assistants.     

基于SOA的ERP系统体系结构的研究

分析了现有ERP系统的局限性,指出现有ERP系统不能适应企业的业务流程重组、不能灵活地支持供应链管理功能,在分析了面向服务架构（SOA）的特点后,提出了面向服务架构的ERP系统体系结构,给出了基于J2EE平台的面向服务架构的具体实现技术。     

基于网络的图形编辑器模型及实现

文中从信息发布和图形交互两个方面提出了基于网络的图形编辑器。分析并确定了图形编辑器的网络实现模型,给出了图形编辑器与服务器的通信模式。在此基础上,给出了服务器的实现过程,并详细介绍了客户端－图形编辑器的具体设计与实现。     

企业级即时通讯技术及其应用

基于网络的协同工作是办公自动化的高层次应用，也是其发展的趋势。而计算机通信交流技术则是网络协同办公的技术的核心。本文介绍了计算机通信交流技术在协同办公中的作用，进而对其最基础与重要的的即时通讯技术进行概述，介绍了局域网即时通讯技术的主流技术，并给出了架构实例。