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1.
In [Kleijn, J., Team Automata for CSCW – A Survey –, Petri Net Technology for Communication-Based Systems—Advances in Petri Nets, LNCS 2472, Springer, 2003, 295–320], Kleijn presented a survey of the use of team automata for the specification and analysis of phenomena from the field of computer supported cooperative work, in particular notions related to groupware systems. In this paper we present a survey of the use of team automata for the specification and analysis of some issues from the field of security. In particular, we show how team automata can adequately be used to model and verify various access control policies, multicast/broadcast communication protocols, and general (cryptographic) communication protocols.  相似文献   

2.
Integration of geographic information has increased in importance because of new possibilities arising from the interconnected world and the increasing availability of geographic information. Ontologies support the creation of conceptual models and help with information integration. In this paper, we propose a way to link the formal representation of semantics (i.e., ontologies) to conceptual schemas describing information stored in databases. The main result is a formal framework that explains a mapping between a spatial ontology and a geographic conceptual schema. The mapping of ontologies to conceptual schemas is made using three different levels of abstraction: formal, domain, and application levels. At the formal level, highly abstract concepts are used to express the schema and the ontologies. At the domain level, the schema is regarded as an instance of a generic data model. At the application level, we focus on the particular case of geographic applications. We also discuss the influence of ontologies in both the traditional and geographic systems development methodologies, with an emphasis on the conceptual design phase.  相似文献   

3.
CSCW系统中协作感知技术的研究   总被引:10,自引:0,他引:10  
在CSCW系统中,协作感知是多用户协同工作的基础。如何向用户提供有效的协作感知是设计实时群件系统接口的关键技术之一。  相似文献   

4.
5.
Lopez  P.G. Skarmeta  A.F.G. 《Computer》2003,36(3):56-62
Designed to facilitate computer-supported cooperative work, ANTS overcomes the major deficiencies found in earlier groupware toolkits at the conceptual, architectural, and technological levels.  相似文献   

6.
We introduce team pushdown automata (PDAs) as a theoretical framework capable of modelling various communication and cooperation strategies in complex, distributed systems. Team PDAs are obtained by augmenting distributed PDAs with the notion of team cooperation or, alternatively, by augmenting team automata with pushdown memory. In a team PDA, several PDAs work as a team on the input word placed on a common one-way input tape. At any moment in time one team of PDAs, each with the same symbol on top of its stack, is active: each PDA in the active team replaces the topmost symbol of its stack and changes state, while the current input symbol is read from the input tape by a common reading head. The teams are formed according to the team cooperation strategy of the team PDA and may vary from one moment to the other. Based on the notion of competence, we introduce a variety of team cooperation strategies. If all stacks are empty when the input word has been completely read, then this word is part of the language accepted by the team PDA. Here we focus on the accepting capacity of team PDA.  相似文献   

7.
A conceptual framework for the integration of data type and process modeling techniques, called integration paradigm, has been presented by the authors in previous papers already. The aim of this paper is to give a short review of this conceptual framework and to present a formal model for the integration paradigm. The formal model for the four layers, called data type, data states and transformations, processes and system architecture layers respectively, is based on an integration of abstract data types and structured transition systems. This formal model can be instantiated by all kinds of basic and integrated modeling techniques. Algebraic high-level nets, attributed graph transformation, an integration of Z with statecharts, and some diagram techniques of UML are discussed on the conceptual level. As instantiation of the formal model, a well-known CCS sender specification, place/transition nets, algebraic high-level nets and attributed graph transformation are presented in this paper, while instantiations of other modeling techniques will be discussed elsewhere.  相似文献   

8.
郑志  杨德礼  杨红 《计算机工程》2008,34(10):35-37
基于Agent技术为复杂分布式问题提供了求解方法。软件体系结构是控制软件复杂性、提高软件系统质量、支持软件开发和复用的重要手段之一。软件体系结构设计可用于描述Agent与Agent之间的交互和组织结构的规划,因此Agent系统能从良好的体系结构设计中受益。该文整合了图表句法理论和层次谓词变迁网理论,提出一种形式化建模方法,从抽象层(架构)和实现层(动态行为)两方面来构建Agent系统的软件体系结构。模型具有可验证和追踪性,为Agent系统软件体系结构分析与评估提供了良好的基础。  相似文献   

9.
For successful information systems development, conceptual data modeling is essential. Nowadays a plethora of techniques for conceptual data modeling exist. Many of these techniques lack a formal foundation and a lot of theory, e.g. concerning updates or schema transformations, is highly data model specific. As such there is a need for a unifying formal framework providing a sufficiently high level of abstraction. In this paper, focus is on the applications of such a framework defined in category theory. Well-known conceptual data modeling concepts, such as relationship types, generalization, specialization, and collection types are defined from a categorical point of view in this framework and an essential advantage is its “configurable semantics”. Features such as null values, uncertainty, and temporal behavior can be added by selecting appropriate instance categories. The addition of these features usually requires a complete redesign of the formalization in traditional set-based approaches to semantics. Applications of the framework in the context of schema transformations and improved automated modeling support are discussed. Received: 10 September 1996 / 19 February 1997  相似文献   

10.
分布式多媒体数据库系统的分层体系结构   总被引:12,自引:1,他引:11  
本文研究分布式多媒体数据库系统的分层体系结构,分析了多媒体数据的表现特征,强调分离出独立的多媒体数据表现模式层的必要性,给出了多媒体数据对象的概念描述,提出了在多媒体计算机概念体系结构基础之上的我媒体数据库系统的分层体系结构框架,并进行了分析,最后给出了灵活的目录制导的分布式多媒体数据库系统结构。  相似文献   

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