Semantic schema refinements for multilevel schema integration

Within the database field, schema refinements have been proved useful for documentation and maintenance purposes; moreover, schemata describing the reality of interest at different levels of abstraction are extensively used in Computer Aided Software Engineering tools and visual query languages. So, much effort has been spent in analyzing schema transformations and schema refinements. Till now, however, while the syntaxof schema transformations has been deeply investigated, the semantics has been very often neglected. In this paper we present a full formal framework, supporting both the syntax and the semantics of schema refinements. Such a formal framework is used to support a methodology able to merge a set of schemata and the top-down chains of refinement planes produced during their design. The result of this kind of integration, that we call multilevel integration, is an integrated schema plus an associated top-down chain of schemata. The integrated schema and the chain are related to the input schemata by interesting properties, giving rise to a two-dimensional structure useful for exploring the data content of complex information systems.     

Semi-automated schema integration with SASMINT

The emergence of increasing number of collaborating organizations has made clear the need for supporting interoperability infrastructures, enabling sharing and exchange of data among organizations. Schema matching and schema integration are the crucial components of the interoperability infrastructures, and their semi-automation to interrelate or integrate heterogeneous and autonomous databases in collaborative networks is desired. The Semi-Automatic Schema Matching and INTegration (SASMINT) System introduced in this paper identifies and resolves several important syntactic, semantic, and structural conflicts among schemas of relational databases to find their likely matches automatically. Furthermore, after getting the user validation on the matched results, it proposes an integrated schema. SASMINT uses a combination of a variety of metrics and algorithms from the Natural Language Processing and Graph Theory domains for its schema matching. For the schema integration, it utilizes a number of derivation rules defined in the scope of the research work explained in this paper. Furthermore, a derivation language called SASMINT Derivation Markup Language (SDML) is defined for capturing and formulating both the results of matching and the integration that can be further used, for example for federated query processing from independent databases. In summary, the paper focuses on addressing: (1) conflicts among schemas that make automatic schema matching and integration difficult, (2) the main components of the SASMINT approach and system, (3) in-depth exploration of SDML, (4) heuristic rules designed and implemented as part of the schema integration component of the SASMINT system, and (5) experimental evaluation of SASMINT.     

基于多中间件的数据集成方案

为了实现分布的异构数据集成,解决"信息孤岛"问题,结合J2EE架构的优势和许多成功的数据集成方案,提出了基于数据访问中间件、消息中间件、数据源集成中间件的数据集成方案.详细讲述了该集成方案的架构和实现,实现结果表明该方案明显提高了数据集成的效率.最后,结合最新技术发展趋势对数据集成的研究前景做出了展望.     

Double-layered schema integration of heterogeneous XML sources

Schema integration aims to create a mediated schema as a unified representation of existing heterogeneous sources sharing a common application domain. These sources have been increasingly written in XML due to its versatility and expressive power. Unfortunately, these sources often use different elements and structures to express the same concepts and relations, thus causing substantial semantic and structural conflicts. Such a challenge impedes the creation of high-quality mediated schemas and has not been adequately addressed by existing integration methods. In this paper, we propose a novel method, named XINTOR, for automating the integration of heterogeneous schemas. Given a set of XML sources and a set of correspondences between the source schemas, our method aims to create a complete and minimal mediated schema: it completely captures all of the concepts and relations in the sources without duplication, provided that the concepts do not overlap. Our contributions are fourfold. First, we resolve structural conflicts inherent in the source schemas. Second, we introduce a new statistics-based measure, called path cohesion, for selecting concepts and relations to be a part of the mediated schema. The path cohesion is statistically computed based on multiple path quality dimensions such as average path length and path frequency. Third, we resolve semantic conflicts by augmenting the semantics of similar concepts with context-dependent information. Finally, we propose a novel double-layered mediated schema to retain a wider range of concepts and relations than existing mediated schemas, which are at best either complete or minimal, but not both. Performed on both real and synthetic datasets, our experimental results show that XINTOR outperforms existing methods with respect to (i) the mediated-schema quality using precision, recall, F-measure, and schema minimality; and (ii) the execution performance based on execution time and scale-up performance.     

Semantic information and knowledge integration through argumentative reasoning to support intelligent decision making

The availability of integrated, high quality information is a pre-requisite for a decision support system (DSS) to aid in the decision-making process. The introduction of semantic web ensures the seamless integration of information derived from diverse sources and transforms the DSS to an adoptable and flexible Semantic Web-DSS (Web-DSS). However, due to the monotonic nature of the layered development of semantic web, it lacks the capability to represent, reason and integrate incomplete and conflicting information. This, in turn, renders an enterprise incapable of knowledge integration; that is, integration of information about a subject that could potentially be incomplete, inconsistent and distributed among different Web-DSS within or across enterprises. In this article, we address the issues of incomplete and inconsistent semantic information and knowledge integration by using argumentation and argumentation schemes. We discuss the Argumentation-enabled Information Integration Web-DSS (Web@IDSS) along with its syntax and semantics for semantic information integration, and devise a methodology for sharing the results of Web@IDSS in Argument Interchange Format (AIF) format. We also discuss Argumentation-enabled Knowledge Integration Web-DSS (Web@KIDSS) for semantic knowledge integration. We provide formal syntax and semantics for the Web@KIDSS, propose a conceptual framework, and describe it in detail. We present the algorithms for knowledge integration and the prototype application for validation of results.     

基于Web Services的智能社区信息系统软件集成框架

当前智能社区建设成了一种趋势,智能社区信息系统软件集成有着广泛的需求。Web服务作为一种新的分布式计算系统具有许多优异的特性,如松散耦合性、集成的灵活性等。结合智能社区信息系统软件集成的需求和Web服务的特点,设计了一种智能社区信息系统软件集成框架,并且通过实例讨论了一些具有共性的问题。     

基于扩展关系代数的数据集成映射模式的研究

集成映射是数据集成领域的基础性问题,尚存在去重效率低,准确度不高等不足。在对数据集成两种基本映射模式全局视图映射(GAV)、本地视图映射(LAV)和模式匹配进行研究的基础上,针对集成映射中去重和布尔元素值与语义值的转换等问题,对关系代数中已有理论进行扩展。设计了一种从源模式到目标模式的映射方案,通过将源模式中对象集合和关系集合进行扩充,而后使用扩展关系代数对扩充后模式进行处理得到目标模式,并给出了操作过程中的具体推导过程。通过举例,对该方案的可行性进行了验证。     

Tableaux-based optimization of schema mappings for data integration

The task of combining data residing at different sources to provide the user a unified view is known as data integration. Schema mappings act as glue between the global schema and the source schemas of a data integration system. Global-and-local-as-view (GLAV) is one the approaches for specifying the schema mappings. Tableaux are used for expressing queries and functional dependencies on a single database. We investigate a general technique for expressing a GLAV mapping by a tabular structure called mapping assertion tableaux (MAT). In a similar way, we also express the tuple generating dependency (tgd) and equality generating dependency (egd) constraints by tabular forms, called tabular tgd (TTGD) and tabular egd (TEGD), respectively. A set consisting of the MATs, TTGDs and TEGDs are called schema mapping tableaux (SMT). We present algorithms that use SMT as operator on an instance of the source schema to produce an instance of the target schema. We show that the target instances computed by the SMT are ‘minimal’ and ‘most general’ in nature. We also define the notion of equivalence between the schema mappings of two data integration systems and present algorithms that optimize schema mappings through the manipulation of the SMT.     

Integrity constraint integration in heterogeneous databases: An enhanced methodology for schema integration

In today's technologically diverse corporate environment, it is common to find several different databases being used to accomplish the organization's operational data management functions. Providing interoperability among these databases is important to the successful operation of the organization. One approach to providing interoperability among heterogeneous database systems, is to define one or more schemas which represent a coherent view of the underlying databases. In the past, most approaches have used schematic knowledge about the underlying databases to generate integrated representations of the databases. In this paper we present a seven step methodology for utilizing integrity constraint knowledge from heterogeneous databases. Specifically, we describe how we can generate a set of integrity constraints applicable at the integrated level from constraints specified on local databases. We introduce the concept of constraint-based relationships between objects in heterogeneous databases and describe the role that these relationships play in integrity constraint integration. Finally, we describe how the integrated set of constraints generated using our methodology can be used to facilitate semantic query processing in a heterogeneous database environment.     

一种自适应信息集成方法

检测相似重复记录是信息集成中的关键任务之一,尽管已经提出了各种检测相似重复记录的方法,但字符串匹配算法是这些检测方法中的核心。在提出的自适应信息集成算法中,用一个综合了编辑距离和标记距离的混合相似度去度量字符串之间的相似度。为了避免由于表达方式的差异而造成的字符串之间的不匹配,字符串被分割成独立的单词后按单词的第一个字符进行排序。在单词的匹配中,对拼写错误和缩写有一定的容错功能。实验结果表明,自适应信息集成方法比用Smith Waterman和Jaro距离有更高的正确率。     

A comprehensive database schema integration method based on the theory of formal concepts

Integrating heterogeneous database schemata is a major task in federated database design where preexisting and heterogeneous database systems need to be integrated virtually by providing a homogenization database interface. Most proposed schema integration methods suffer from very complex result schemata and insufficient handling of extensional relations, i.e. in the way how redundant data of the input systems are dealt with. Redundancy among the input systems may thus remain undetected and, hence, remains uncontrolled.Our GIM (Generic Integration Model) method is based on the elegant and mathematically founded theory of formal concept analysis (FCA). The main idea is to integrate schemata into one formal context which is a binary relation between a set of attributes and a set of base extensions (set of potential objects). From that context we apply an FCA-algorithm to semi-automatically derive a concept lattice which we interpret as an inheritance hierarchy of classes for a homogenized schema. Thus, the integration task following our method can be supported by tools.     

数据集成中不确定性模式匹配模型的研究

针对已有模式匹配中证据组合方法效率较低的缺点,提出一个能够处理不确定性模式匹配的模型——USMM(Uncertain Schema Matching Model)。该模型是多维混合模型,其中运用领域知识和证据组合方法处理模式匹配中的不确定性,以降低匹配复杂度;利用模式的多维结构信息挖掘匹配中内在的不确定性;在计算名称相似度的公式中加入可信度来细化匹配的不确定度。最后形式化定义了不确定模式匹配、不确定匹配关系。实例分析证明该模型是可行的,具有较高的实用价值。     

基于XML元数据和Schema的Excel信息提取研究

针对地质工作单位中使用的复杂格式的Excel报表中的信息同数据库之间转储的困难,提出了采用XML语言描述的元数据模型来辅助表达Excel报表中的信息。使用XML Schema定义XML元数据语法,使得基于元数据的应用程序来提取Excel报表中信息变得更加灵活通用。     

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.     

不确定模式集成中领域知识应用模型的研究

结合关系模型、产生式规则和自主计算三者的优点,提出了一个任务驱动的自主推理的动态领域知识应用模型。在该模型中,将领域知识按需要进行聚类,根据任务进行规则映射和推理模块中不同处理器的选择,运用证据组合方法合并各处理阶段的不确定度,采用基于自适应控制策略的自主计算技术进行知识推理。推理结果被应用到不确定模式集成模型的其他模块中,辅助解决模式集成中存在的不确定性问题。经实例验证该模型是可行的。     

Structural schema integration with full and partial correspondence using the dual model

The integration of views and schemas is an important part of database design and evolution and permits the sharing of data across complex applications. The view and schema integration methodologies used to date are driven purely by semantic considerations, and allow integration of objects only if that is valid from both semantic and structural view points. We discuss a new integration method called structural integration that has the advantage of being able to integrate objects that have structural similarities, even if they differ semantically. This is possible by using the object-oriented Dual Model which allows separate representation of structure and semantics. Structural integration has several advantages, including the identification of shared common structures that is important for sharing of data and methods.     

Concepts and terminology for the conceptual schema and the information base

This paper reports on the definitional work of ISO/TC97/SC5/WG3 on Conceptual Schemas and related concepts in database management and computerised information systems. The roles and contents of a Conceptual Schema are described, and the relationship of the Conceptual Schema to information modelling and data semantics is defined. An important part of the specification of an information system is the precise definition of both static and dynamic rules in the Conceptual Schema. The architectural role of the Conceptual Schema and how current database management systems and data dictionaries fit into such an architecture are discussed.     

A hypothesis of consciousness or intelligent neuronet information systems

This paper deals with the problematics of artificial intelligence and is devoted to problems of investigation of natural systems and synthesis of artificial intelligence systems. The specificity of functioning of biological intelligence systems is illustrated by simple examples. These examples allow one to disclose a probable mechanism that provides the formation of consciousness inherent in living beings and whose explicit manifestation is thinking. The natural-science aspect of the content of fundamental concepts such as semantics and knowledge is also considered as applied to the functioning of these systems. Based on paradigms of several scientific schools and that of system approach, general concepts and approaches to the solution of the problem of artificial intelligence are presented.Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 73–86, November–December 2004.This revised version was published online in April 2005 with a corrected cover date.