一种基于刻面分类描述的软件构件查询方法

该文分析了软件构件的刻面分类描述的特点,通过借鉴XML查询语言ApproXQL中树匹配的思想及其相关理论,提出了一种新的基于刻面分类的软件构件查询方法。该方法将基于刻面分类的构件XML描述文档映射为一棵构件树,将查询表达式映射为一棵查询树,通过构件树与查询树之间的匹配算法查找需要的软件构件。这种查询方法支持布尔查询和模糊查询,具有一定的张弛能力,能在保证一定查准率的基础上提高查全率。该方法适用于面向网络的跨构件库查询。     

基于移动Agent技术的构件软件框架研究

随着移动Agent技术的快速发展以及构件软件的广泛应用,对一种新型的基于移动agent技术 的构件软件框架的需求日益增长.通过对传统的构件软件框架的不足的分析,提出了一种新的 构件软件框架.与传统的构件软件框架相比,新的构件软件框架具有较强的网络环境的动态适 应性.     

基于本体的构件匹配研究

针对刻面描述的构件检索中缺少语义信息的问题,提出了一种基于本体的构件检索框架.按照所给出的构件描述模型,将用户查询的构件从功能、环境和质量属性三个方面与语义构件库中的构件进行匹配.建立在上海构件库的初步实验结果表明,该原型系统能有效地提高构件检索的查准率和查全率.     

一种面向对象的软件复用框架

本文利用面向对象技术,提出了一种面向对象的软件复用框架,该框架采用面向对象的类来实现构件,为了提高构件库的组织管理效率,采用为构件库建立多个索引链等策略,构件检索采用模糊查询和详细查询的两个阶段来实现,构件集成采用基于星型拓扑结构的构件集成方法。     

基于刻面描述的构件查询匹配模型及算法研究

在软件复用研究不断深入的情况下，软件构件库的管理研究得到了产业界与学术界越来越多的重视．作为构件库管理的两个核心技术，构件的表示与检索技术已经成为研究热点，其中基于刻面描述的构件相关应用得到了广泛研究，针对构件查询的特点，结合模式分析中的树匹配思想，提出了新颖的构件树路径包含匹配模型及其相应的构件查询匹配算法，该算法可以在保持构件查准率的前提下，有效提高构件的查全率，算法的时间复杂度和空间复杂度是线性的，实验表明具有良好的查询效率．     

青鸟网上构件库系统的访问控制机制

青鸟网上构件库系统通过对可复用构件的管理,支持软件企业进行基于构件的软件开发.系统在提高开放性的同时,往往会带来安全性以及知识产权方面的问题.为了解决这些问题,在青鸟网上构件库系统中采用基于角色的访问控制机制,并将构件描述信息与构件实体区别对待.为构件库系统及其所管理的构件定义了用户、角色、权限和角色继承,满足了安全性、知识产权管理等多种需求,同时也保证了系统的效率和对复用的支持.     

新型网络环境下的访问控制技术

访问控制是系统安全的关键技术,不同网络环境下的访问控制机制也是不同的.首先对3种传统的访问控制策略加以介绍,给出DAC(discretionary access control),MAC(mandatory access control)和RBAC(role-based access control)各自的特点及应用,并简要介绍下一代访问控制UCON(usage control)模型,然后分别针对网格、P2P、无线网络环境下的访问控制技术及目前的研究现状进行总结,详细阐述可信网络作为下一代互联网发展的必然     

软件配置构件分类及优化查询方法研究

针对软件不同的质量和管理要求,结合软件本身的规模和特点,设计软件配置构件管理方法。给出优先级刻面的构件分类方法PF-CCM,用于优化构件检索与查询。结合索引、关键词和刻面3种构件检索机制,提出一种基于剪枝的优化匹配方法POMA,根据刻面优先级对查询结果进行排序。实验结果表明,POMA方法能有效提高配置构件的查询效率。     

基于XML的软件构件查询匹配算法研究

在研究无序树包含匹配的基础上,提出一种新的基于XML的软件构件查询匹配算法.该算法可以在保持较高构件查准率的前提下,显著地提高构件的查全率,并提供对布尔查询的支持.此外,通过合理地设定约束条件以及利用动态规划的方法,将计算查询匹配代价的算法时间复杂度限定为多项式级,确保构件查询具有足够的查询效率.最后,通过在构件库原型系统RCRS上进行的一系列实验,进一步证明了新的查询匹配算法在软件构件查询实际应用中的可行性和有效性.     

基于刻面描述的构件查询匹配模型及算法研究

在软件复用研究不断深入的情况下，软件构件库的管理研究得到了产业界与学术界越来越多的重视。作为构件库管理的两个核心技术，构件的表示与检索技术已经成为研究热点，其中基于刻面描达的构件相关应用得到了广泛研究，针对构件查询的特点，结合模式分析申的树匹配思想，本文提出了一种新颖的构件树路径包含匹配模型及其相应的构件查询匹配算法，该算法可以在保持构件查准率的前提下，有效提高构件的查全率，算法的时间复杂度和空间复杂度是线性的，试验表明具有良好的查询效率。     

A secure information service for monitoring large scale grids

The Grid Information Service (GIS) is a core component in the Grid software infrastructure. It provides diverse information to users or other service components in Grid environments. In this paper, we propose a scalable GIS architecture for information management in a large scale Grid Virtual Organization (VO). This architecture consists of the VO layer, site layer and resource layer: at the resource layer, information agents and pluggable information sensors are deployed on each resource monitored. This information agent and sensor approach provides a flexible framework that enables specific information to be captured; at the site layer, a site information service component with caching capability aggregates and maintains up-to-date information of all the resources monitored within an administrative domain; at the VO layer, a peer-to-peer approach is used to build a virtual network of site information services for information discovery and query in a large scale Grid VO. This decentralized approach makes information management scalable and robust. Furthermore, we propose a security framework for the GIS, which provide security policies for authentication and authorization control of the GIS at both the site and the VO layers. Our GIS has been implemented based on the Globus Toolkit 4 as Web services compliant to Web Services Resource Framework (WSRF) specifications. The experimental results show that the GIS presents satisfactory scalability in handling information for large scale Grids.     

LESSON: A system for lecture notes searching and sharing over Internet

In this paper, we present a system LESSON for lecture notes searching and sharing, which is dedicated to both instructors and students for effectively supporting their Web-based teaching and learning activities. The LESSON system employs a metasearch engine for lecture notes searching from Web and a peer-to-peer (P2P) overlay network for lecture notes sharing among the users. A metasearch engine provides an unified access to multiple existing component search engines and has better performance than general-purpose search engines. With the help of a P2P overlay network, all computers used by instructors and students can be connected into a virtual society over the Internet and communicate directly with each other for lecture notes sharing, without any centralized server and manipulation. In order to merge results from multiple component search engines into a single ranked list, we design the RSF strategy that takes rank, similarity and features of lecture notes into account. To implement query routing decision for effectively supporting lecture notes sharing, we propose a novel query routing mechanism. Experimental results indicate that the LESSON system has better performance in lecture notes searching from Web than some popular general-purpose search engines and some existing metasearch schemes; while processing queries within the system, it outperforms some typical routing methods. Concretely, it can achieve relatively high query hit rate with low bandwidth consumption in different types of network topologies.     

非结构化P2P网络的增量式查询

基于非结构化P2P网络的应用日益广泛,参与共享资源的节点越来越多,且呈海量增长趋势.如何在海量节点、海量资源的情况下,对同一查询语义进行增量式查询,是一个重要而颇具挑战性的问题.提出了一个通用的近似依相关性大小的非结构化P2P网络增量式查询算法模型,该算法模型使得针对同一查询语义的增量式查询尽力优先访问与语义最为相关的节点,从而在完全分布式的P2P网络中获得类似Google[1]的依据资源相关性排序显示及其"下一页"的功能.     

Skyframe: a framework for skyline query processing in peer-to-peer systems

This paper looks at the processing of skyline queries on peer-to-peer (P2P) networks. We propose Skyframe, a framework for efficient skyline query processing in P2P systems, which addresses the challenges of quick response time, low network communication cost and query load balancing among peers. Skyframe consists of two querying methods: one is optimized for network communication while the other focuses on query response time. These methods are different in the way in which the query search space is defined. In particular, the first method uses a high dominating point that has a large dominating region to prune the search space to achieve a low cost in network communication. On the other hand, the second method relaxes the search space in order to allow parallel query processing to speed up query response. Skyframe achieves query load balancing by both query load conscious data space splitting/merging during the join/departure of nodes and dynamic load migration. We further show how to apply Skyframe to both the P2P systems supporting multi-dimensional indexing and the P2P systems supporting single-dimensional indexing. Finally, we have conducted extensive experiments on both real and synthetic data sets over two existing P2P systems: CAN (Ratnasamy in A scalable content-addressable network. In: Proceedings of SIGCOMM Conference, pp. 161–172, 2001) and BATON (Jagadish et al. in A balanced tree structure for peer-to-peer networks. In: Proceedings of VLDB Conference, pp. 661–672, 2005) to evaluate the effectiveness and scalability of Skyframe.     

OLAP query reformulation in peer-to-peer data warehousing

Inter-business collaborative contexts prefigure a distributed scenario where companies organize and coordinate themselves to develop common and shared opportunities, but traditional business intelligence systems do not provide support to this end. To fill this gap, in this paper we envision a peer-to-peer data warehousing architecture based on a network of heterogeneous peers, each exposing query answering functionalities aimed at sharing business information. To enhance the decision making process, an OLAP query expressed on a peer needs to be properly reformulated on the local multidimensional schemata of the other peers. To this end, we present a language for the definition of mappings between the multidimensional schemata of peers and we introduce a query reformulation framework that relies on the translation of mappings, queries, and multidimensional schemata onto the relational level. Then, we formalize a query reformulation algorithm and prove two properties: correctness and closure, that are essential in a peer-to-peer setting. Finally, we discuss the main implementation issues related to the reformulation setting proposed, with specific reference to the case in which the local multidimensional engines hosted by peers use the standard MDX language.     

Querying distributed data through distributed ontologies: a simple but scalable approach

This framework for peer-to-peer data-sharing systems allows efficient query answering over a network of semantically related peers. A simple class-based language appropriate for practical applications defines peer schemas as hierarchies of atomic classes and mappings as inclusions of logical combinations of atomic classes.     

一种支撑构件重叠网的中间件技术研究

随着对等计算的广泛应用,对等应用软件的设计与开发方法研究,是当前软件工程领域一个值得关注的问题.遵循软件复用的思想,提出一种适应于对等应用软件设计与开发的构件化重叠网中间件技术.该技术涵盖支撑构件重叠网的中间件模型、及其实现框架等两方面内容,分别用于对等应用软件的设计时与开发阶段.相关对比实验结果表明,该技术是可行和有效的.     

An Adaptive Object-Oriented Approach to Integration and Access of Heterogeneous Information Sources

A large-scale interoperable database system operating in a dynamic environment should provide Uniform access to heterogeneous information sources, Scalability to the growing number of information sources, Evolution and Composability of software and information sources,and Autonomy of participants,both information consumers and information producers. We refer to these set of properties as the USECA properties [29]. To address the research issues presented by such systems in a systematicmanner, we introduce the Distributed Interoperable Object Model (DIOM). DIOM promotes an adaptive approach to interoperation via intelligent mediation [46, 47], aimedat enhancing the robustness and scalability of theservices provided for integrating and accessing heterogeneous information sources. DIOM‘s main features include (1) the recursive construction and organizationof information access through a network of application-specificmediators, (2)the explicit use of interface composition meta operations(such as specialization, generalization, aggregation, import and hide) to support the incremental design and construction of consumer‘s domain query model, (3) the deferment of semantic heterogeneity resolution to the query result assembly time instead of before or at the time of query formulation, and (4) the systematic development of the query mediation framework and the procedure of each query processing step from query routing, query decomposition, parallel access planning, query translation to query result assembly.To make DIOM concrete, we outline the DIOM-based information mediation architecture, which includes important auxiliary services such as domain-specific metadatalibrary and catalog functions, object linking databases, and associatedquery services. Several practical examples and application scenarios illustrate the flavor of DIOM query mediation framework and the usefulness of DIOM in multi-database query processing.     

Traceable P2P record exchange: a database-oriented approach

In recent years, peer-to-peer (P2P) technologies are used for flexible and scalable information exchange in the Internet, but there exist problems to be solved for reliable information exchange. It is important to trace how data circulates between peers and how data modifications are performed during the circulation before reaching the destination for enhancing the reliability of exchanged information. However, such lineage tracing is not easy in current P2P networks, since data replications and modifications are performed independently by autonomous peers—this creates a lack of reliability among the records exchanged. In this paper, we propose a framework for traceable record exchange in a P2P network. By managing historical information in distributed peers, we make the modification and exchange histories of records traceable. One of the features of our work is that the database technologies are utilized for realizing the framework. Histories are maintained in a relational database in each peer, and tracing queries are written in the datalog query language and executed in a P2P network by cooperating peers. This paper describes the concept of the framework and overviews the approach to query processing.     

一种基于对等计算的构件模型研究

基于构件的软件开发,是软件工程领域一个重要的方法,其中构件模型是该方法的理论基础.目前,适用于基于对等结构的分布式应用软件开发的构件模型尚不多见.针对对等应用软件的特点,首先在给出一个开发框架的前提下,对对等应用软件进行了构件特征分析,并将基于该框架开发的对等应用软件系统所涉及到的构件形态,归结为可迁移构件、轻量级构件和耦合容器构件3类,然后在此基础上提出一个支持对等应用的构件模型,并对构件模型中语义和语法进行了表述,最后介绍了该构件模型的生成与部署、合成与组装、查找与匹配、通讯与协作、以及相关对比等方面的研究工作.