Knowledge-based repository scheme for storing and retrieving business components: a theoretical design and an empirical analysis

Component-based development (CDB) promises to reduce complexity and cost of software development and maintenance through reuse. For CBD to be successful, a vibrant market for commercial business components is essential. One of the key requirements of an active market for business components is an effective scheme for classifying and describing them at various levels of detail, as well as a corresponding repository for storing and retrieving these components. Such a scheme needs to support various constituents such as business users, managers, and application assemblers. The scheme and repository should help users and managers to select components that match their requirements and aid application assemblers in identifying components most compatible with their deployment environment (such as the platform) and system inputs (such as data types). Drawing from the concepts of group technology and software reuse paradigm, this paper proposes a scheme for classifying and describing business components and the design of a knowledge-based repository for their storage and retrieval. The proposed scheme is implemented in a prototype repository. The effectiveness of the prototype and the underlying classification and coding scheme is assessed empirically through controlled experiments. Results support the assertion that the scheme is effective in enhancing the users' and analysts' ability to find the needed business components.     

基于本体的信息集成框架中包装器的设计

将本体应用在信息集成框架中能够在语义层次上消除底层数据源的异构,但是本体只相当于一个知识库,在定义用户接口时,需要赋予其一个语法结构,这个语法结构可作为与用户交互的全局模式,从本体到全局模式的转换可以用包装器来实现。而此全局模式和各个数据源之间的局部模式也需要映射,这些映射也可以用包装器来实现。该文提出了基于本体的信息集成框架中一种包装器的设计,通过将本体转换为XMLSchema作为全局模式,并利用XSLT实现全局模式和局部模式的映射,从而屏蔽了数据源的异构性。     

基于Agent的Peer-to-Peer式分布式构件库系统

为解决构件库中存在的种种问题,在分析了软件复用现状和构件库的特点的基础上,提出了一种基于Agent的P2P式的分布式构件库系统,阐述了系统的体系结构并在理论基础上开发出了原型系统。该系统能够达到软构件复用的目的,验证了方法的可行性。     

A C++ data model supporting reachability analysis and dead codedetection

A software repository provides a central information source for understanding and reengineering code in a software project. Complex reverse engineering tools can be built by analyzing information stored in the repository without reparsing the original source code. The most critical design aspect of a repository is its data model, which directly affects how effectively the repository supports various analysis tasks. This paper focuses on the design rationales behind a data model for a C++ software repository that supports reachability analysis and dead code detection at the declaration level. These two tasks are frequently needed in large software projects to help remove excess software baggage, select regression tests and support software reuse studies. The language complexity introduced by class inheritance, friendship, and template instantiation in C++ requires a carefully designed model to catch all necessary dependencies for correct reachability analysis. We examine the major design decisions and their consequences in our model and illustrate how future software repositories can be evaluated for completeness at a selected abstraction level. Examples are given to illustrate how our model also supports variants of reachability analysis: impact analysis, class visibility analysis, and dead code detection. Finally, we discuss the implementation and experience of our analysis tools on a few C++ software projects     

一种基于UML关系的Java代码库构造方法

关系信息是体现代码结构和语义的最重要的一类信息,如继承、聚合、组合、依赖、调用和创建实例等。为了更好地支持开源代码的理解与复用,提出了一种基于UML2关系的代码库构造方法。它以图数据库为实现平台,采用语言工程中经典的抽象语法树作为基础,并针对Java语言的特性和机制,设计富语义的Java代码属性图数据模型,在此基础上使得Java代码的图结构持久化。同时,为了屏蔽各种编程语言社区对代码中关系信息理解的差异性,采用UML2.4国际标准版本中定义的关系类型及语义解释,设计相应的代码关系抽取算法,为图节点添加对应的关系边。针对代码图化后的膨胀及代码库的空间存储消耗情况,选取9个常见的开源项目进行了实验评估。最后,给出了基于此代码库的查询应用实例。     

Knowledge management through the development of information schema

Knowledge management (KM) has been receiving considerable attention in the human-systems research community in the past few years. This paper discusses the key concepts of user–computer interaction for knowledge development and proposes a model of an information schema. Such an information repository for KM must be organized into a domain schema. Users of an information repository play an active role in searching through information to coordinate their actions. An example of information schema for KM can be found in a student advising system. This will be used to illustrate the concept of the development of an information schema.     

Normalization of Class Hierarchy in Databases

In complex object oriented databases,the purpose of introducing class hierarchy is to express ISA semantics,to realize inheriting and to reuse schema definition codes.The schema defintition and schema evolution,based on the partial order of lattice,often cause the loss o information inheriting and the redundance of schema definition.Based on the fullness of the inheritance shown by class hierarchy,three normal forms of class hierarchy are given in this paper,and a general algorithm of normalization of class hierarchy is presented,following the Boolean algebra model of class hierarchy.The loss of information inheritance can be avoided when they are applied to schema design and schema evolution.     

LDAP在基于域的网络管理中应用的研究

文章通过对基于域的网络管理系统模型的研究,分析了模型中数据存储的特点,给出了一个基于LDAP的数据存储解决方案。介绍了基于LDAP目录存储的优点,对LDAP在网络管理系统中应用的可能性进行了分析。文章详细描述了如何使用LDAP模式(Schema)脚本定义网络管理信息对象类和属性,并通过命名规则建立LDAP目录树。     

Database reverse engineering: From the relational to the binary relationship model

This paper describes an algorithmic method for transforming a relational database schema to a binary-relationship one. The source schema may consist of relations that are at any level of normalization, and the designer may add semantic information on the source schema, such as the definition of candidate keys, foreign keys, functional dependencies of various types, multi-valued dependencies, many-to-many constraints, inclusion dependencies, and others. Based on this information, the multi-stage transformation algorithm applies mapping rules to generate object-types, binary-relationships and constraints in the target conceptual schema. The method is implemented as a PC-based tool, utilizing Ingres, SQL and C, and is part of a comprehensive database design tool for both forward and reverse engineering.     

Semantic Web based innovative design knowledge modeling for collaborative design

This paper describes a study about how to use the Semantic Web technologies for innovative design knowledge modeling in a multi-agent distributed design environment. Semantic Web based knowledge modeling for innovative design is proposed as prelude to the meaningful agent communication and knowledge reuse for collaborative work among multidisciplinary organizations. A model for innovative design is proposed at first, based on which a knowledge schema is brought forward. For sharing the design knowledge among an internet-based or distributed work team, even globally, A RDF-based knowledge model is presented to realize its representation on Semantic Web. A Semantic Web based repository for innovative design and its API for topper Semantic Web applications have been also constructed. The proposed knowledge modeling extends traditional product modeling with capabilities of innovative design, knowledge sharing and distributed problem solving, and is employed as a content language within the messages in the proposed multi-agent system architecture. The proposed approach is viewed as a promising knowledge management method that facilitates the implementation of computer supported cooperative work in innovative design of Semantic Web applications.     

Sharing,finding and reusing end-user code for reformatting and validating data

To help users with automatically reformatting and validating spreadsheets and other datasets, prior work introduced a user-extensible data model called “topes” and a supporting visual programming language. However, no support has existed to date for users to exchange and reuse topes. This functional gap results in wasteful duplication of work as users implement topes that other people have already created.In this paper, a design for a new repository system is presented that supports sharing and finding of topes for reuse. This repository tightly integrates traditional keyword-based search with two additional search methods whose usefulness in repositories of end-user code has gone unexplored to date. The first method is “search-by-match”, where a user specifies examples of data, and the repository retrieves topes that can reformat and validate that data. The second method is collaborative filtering, which has played a vital role in repositories of non-code artifacts.The repository’s search functionality was empirically tested on a prototype repository implementation by simulating queries generated from real user spreadsheets. This experiment reveals that search-by-match and collaborative filtering greatly improve the accuracy of search over the traditional keyword-based approach, to a recall as high as 95%. These results show that search-by-match and collaborative filtering are useful approaches for helping users to publish, find, and reuse visual programs similar to topes.     

A development environment for customer-oriented Internet business: eBizBench

An important challenge in the age of Internet business is the proper alignment of customers’ needs with the business system. In order to improve an Internet business system according to customers’ needs continuously, reuse of design results is of particular importance. This paper proposes a development environment, called eBizBench, which provides support for this alignment and reusability. The eBizBench includes seven functions: (1) project management, (2) customer analysis, (3) value analysis, (4) web design, (5) implementation design, (6) repository management, and (7) repository. The eBizBench can help develop and maintain Internet business systems in a systematic fashion. The repository is useful for the conversion of design results among development environments. A real-life web site is illustrated to demonstrate the usefulness of the eBizBench.     

Weaving temporal and reliability aspects into a schema tapestry

In aspect-oriented programming (AOP) a cross-cutting concern is implemented in an aspect. An aspect weaver blends code from the aspect into a program’s code at programmer-specified cut points, yielding an aspect-enhanced program. In this paper, we apply some of the concepts from the AOP paradigm to data. Like code, data also has cross-cutting concerns such as versioning, security, privacy, and reliability. We propose modeling a cross-cutting data concern as a schema aspect. A schema aspect describes the structure of the metadata in the cross-cutting concern, identifies the types of data elements that can be wrapped with metadata, i.e., the cut points, and provides some simple constraints on the use of the metadata. Several schema aspects can be applied to a single data collection, though in this paper we focus on just two aspects: a reliability aspect and a temporal aspect. We show how to weave the schema for these two aspects together with the schema for the data into a single, unified schema that we call a schema tapestry. The tapestry guides the construction, interpretation, and validation of an aspect-enhanced data collection.     

Weaving temporal and reliability aspects into a schema tapestry

In aspect-oriented programming (AOP) a cross-cutting concern is implemented in an aspect. An aspect weaver blends code from the aspect into a program’s code at programmer-specified cut points, yielding an aspect-enhanced program. In this paper, we apply some of the concepts from the AOP paradigm to data. Like code, data also has cross-cutting concerns such as versioning, security, privacy, and reliability. We propose modeling a cross-cutting data concern as a schema aspect. A schema aspect describes the structure of the metadata in the cross-cutting concern, identifies the types of data elements that can be wrapped with metadata, i.e., the cut points, and provides some simple constraints on the use of the metadata. Several schema aspects can be applied to a single data collection, though in this paper we focus on just two aspects: a reliability aspect and a temporal aspect. We show how to weave the schema for these two aspects together with the schema for the data into a single, unified schema that we call a schema tapestry. The tapestry guides the construction, interpretation, and validation of an aspect-enhanced data collection.     

面向对象知识模型的构建

介绍了面向对象技术设计知识库模式的方法。强调知识模型构建的重点是在表达、验证及推导设计限制条件，而不是传统意义上的数据。设计概念仍沿用类表示，分3个部分：决策参数、表现参数及限制条件。决策参数是从限制条件中抽象出来的数据，代表设计对象的属性或状态；表现参数是对决策参数的计算和度量；限制条件规范及限制表现参数的域值，可视为类不变量，每个类对象都必需满足之。设计概念之间的相互联系则用关联来阐述。传统面向对象技术考虑的是数据在关联中的横向、纵向传递，提出关联类以捕获数据，同时增加关联的限制条件作为关联不变量。在继承和整件-部件关联的基础上，增加了特性关联。模型构建构建以汽车制造中模板设计为例加以说明。     

Towards Deeper Understanding of the Search Interfaces of the Deep Web

Many databases have become Web-accessible through form-based search interfaces (i.e., HTML forms) that allow users to specify complex and precise queries to access the underlying databases. In general, such a Web search interface can be considered as containing an interface schema with multiple attributes and rich semantic/meta-information; however, the schema is not formally defined in HTML. Many Web applications, such as Web database integration and deep Web crawling, require the construction of the schemas. In this paper, we first propose a schema model for representing complex search interfaces, and then present a layout-expression based approach to automatically extract the logical attributes from search interfaces. We also rephrase the identification of different types of semantic information as a classification problem, and design several Bayesian classifiers to help derive semantic information from extracted attributes. A system, WISE-iExtractor, has been implemented to automatically construct the schema from any Web search interfaces. Our experimental results on real search interfaces indicate that this system is highly effective.     

Selected Research Issues in Decision Support Databases

A flurry of buzzwords awaits anyone investigating database technology for decision support: data warehouse, multidimensional and dimensional database, on-line analytical processing, star schema, slicing, dicing, drill-down and roll-up. We introduce the area via an example based on a long-ago project to design a repository on energy information for the US Department of Energy. Once we have introduced some terminology, we explore research issues associated with decision-support databases, including representation, modeling, metadata, architectures and query processing. The purpose of this paper is to provide researchers with the background they need to contribute to this area.