Formal transformation from fuzzy object-oriented databases to fuzzy XML

XML has become the standard for publishing and exchanging data on the Web. Since most of the business data nowadays are stored in structured databases including relational and object-oriented databases (OODB), it is of significance to automate the transformation process and generate the XML data containing information from existing databases. At the same time, information imprecision and uncertainty exist in many practical applications, and for this reason, fuzzy data modeling has been extensively investigated in various data models. As such, there is an increasing need to effectively publish fuzzy structured data as fuzzy XML documents for Web-based applications. In this paper, we take a significant step in a fundamental consolidation of fuzzy XML. In particular, we are interested in finding an XML schema that best describes the existing fuzzy object-oriented schema. To accomplish this, we first offer mapping formalisms to capture the semantics of fuzzy XML Schema and fuzzy object-oriented schema. To allow for better and platform independent sharing of data stored in an object-oriented format, we investigate the formal transformation from fuzzy OODB to fuzzy XML and develop a set of rules to assist in the transformation process.     

Using Constraint Programming in Selection Operators for Constraint Databases

Constraint Databases represent complex data by means of formulas described by constraints (equations, inequations or Boolean combinations of both). Commercial database management systems allow the storage and efficient retrieval of classic data, but for complex data a made-to-measure solution combined with expert systems for each type of problem are necessary. Therefore, in the same way as commercial solutions of relational databases permit storing and querying classic data, we propose an extension of the Selection Operator for complex data stored, and an extension of SQL language for the case where both classic and constraint data need to be managed. This extension shields the user from unnecessary details on how the information is stored and how the queries are evaluated, thereby enlarging the capacity of expressiveness for any commercial database management system. In order to minimize the selection time, a set of strategies have been proposed, which combine the advantages of relational algebra and constraint data representation.     

关系知识表达模式及在专家系统中的应用

采用关系模式表达知识，可以利用当前流行的关系数据库管理系统（ＲＤＢＭＳ），将专家系统与ＲＤＢＭＳ上建立的管理信息系统，决策支持系统，办公自动化系统等有机结合，有利于知识的管理、存储和利用。并可在大量的管理信息，决策支持信息以及办公自动化信息中发现知识，使信息与知识共享。本文研究用关系模式表达知识的方法，并在一分类专家系统中利用ＲＤＢＭＳ强大的数据处理能力实现知识推理。     

Uniform data access platform for SQL and NoSQL database systems

Integration of data stored in heterogeneous database systems is a very challenging task and it may hide several difficulties. As NoSQL databases are growing in popularity, integration of different NoSQL systems and interoperability of NoSQL systems with SQL databases become an increasingly important issue. In this paper, we propose a novel data integration methodology to query data individually from different relational and NoSQL database systems. The suggested solution does not support joins and aggregates across data sources; it only collects data from different separated database management systems according to the filtering options and migrates them. The proposed method is based on a metamodel approach and it covers the structural, semantic and syntactic heterogeneities of source systems. To introduce the applicability of the proposed methodology, we developed a web-based application, which convincingly confirms the usefulness of the novel method.     

Efficient Set-Correlation Operator Inside Databases

Large scale of short text records are now prevalent, such as news highlights, scientific paper citations, and posted messages in a discussion forum, and are often stored as set records in hidden-Web databases. Many interesting information retrieval tasks are correspondingly raised on the correlation query over these short text records, such as finding hot topics over news highlights and searching related scientific papers on a certain topic. However, current relational database management systems (RDBMS) do not directly provide support on set correlation query. Thus, in this paper, we address both the effectiveness and the efficiency issues of set correlation query over set records in databases. First, we present a framework of set correlation query inside databases. To the best of our knowledge, only the Pearson’s correlation can be implemented to construct token correlations by using RDBMS facilities. Thereby, we propose a novel correlation coefficient to extend Pearson’s correlation, and provide a pure-SQL implementation inside databases. We further propose optimal strategies to set up correlation filtering threshold, which can greatly reduce the query time. Our theoretical analysis proves that with a proper setting of filtering threshold, we can improve the query efficiency with a little effectiveness loss. Finally, we conduct extensive experiments to show the effectiveness and the efficiency of proposed correlation query and optimization strategies.     

Uncertainty in a nested relational database model

Some database models have already been developed to deal with complex values but they have constrains that data stored is precise and queries are crisp. However, as many researchers have pointed out, there is a need to present, manipulate, and query complex and uncertain data of various non-traditional database applications such as oceanography, multimedia, meteorology, office automation systems, engineering designs, expert database systems and geographic information systems. In this paper, we present a logical database model, which is an extension of a nested relational data model (also known as an NF² data model), for representing and manipulating complex and uncertain data in databases. We also introduce a possible physical representation of such complex and uncertain values in databases and describe the query processing of the model that we discuss here.     

面向对象模型对复杂结构知识的表示方法

传统关系型数据库在表示专家系统中具有嵌套、递归等复杂结构的知识时遇到了困难。对此，本文提出了一种采用对象模型的解决方案。该方案在关系数据库的基础上使用映射原理实现了一种面向对象的模型，利用该模型可以较好地在数据库中表示各类复杂结构的知识。该方案已经在地震预报专家系统中得到应用，并取得了较好的效果。     

Expert system-user integrated adaptive systems

Many expert systems operate in dynamic environments where various pertinent environmental variables and conditions vary with the passage of time. These environmental variables and conditions may affect both the set of conditions applied to input variables of expert systems and the set of recommendations provided by expert systems. For this reason, expert systems developed according to dynamic structure will generate timely recommendations. To incorporate dynamic characteristics into the structure of expert systems, it is necessary to develop expert systems as adaptive systems. This paper intends to integrate concepts of learning and adaptiveness into expert system technology.

Expert systems used to assist loan officers in improving the decision-making process of commercial loans are typical examples of expert systems that operate in dynamic environments. This paper illustrates that the quality of information provided to loan officers by expert systems may be improved when expert systems are designed as adaptive expert systems.     

Expert systems and database systems: how can they serve each other?

Abstract Expert systems are becoming increasingly complex and diverse. The need for efficient data management for their growing knowledge bases is apparent. Moreover, with the widespread use of Database Management Systems, the operational data required by the expert system is often already available from an online database. Hence the interaction of expert systems and databases is a topic which is receiving increasing attention. This paper reviews existing techniques for such interaction and describes a novel dictionary–driven approach to the problem, called a Dictionary Interface for Expert Systems and Databases (Difead). A prototype of Difead is described, which couples a Medical Diagnosis System, written in Lisp, with a relational database.     

The IKBALS project: Multi-modal reasoning in legal knowledge based systems

In attempting to build intelligent litigation support tools, we have moved beyond first generation, production rule legal expert systems. Our work integrates rule based and case based reasoning with intelligent information retrieval.When using the case based reasoning methodology, or in our case the specialisation of case based retrieval, we need to be aware of how to retrieve relevant experience. Our research, in the legal domain, specifies an approach to the retrieval problem which relies heavily on an extended object oriented/rule based system architecture that is supplemented with causal background information. We use a distributed agent architecture to help support the reasoning process of lawyers.Our approach to integrating rule based reasoning, case based reasoning and case based retrieval is contrasted to the CABARET and PROLEXS architectures which rely on a centralised blackboard architecture. We discuss in detail how our various cooperating agents interact, and provide examples of the system at work. The IKBALS system uses a specialised induction algorithm to induce rules from cases. These rules are then used as indices during the case based retrieval process.Because we aim to build legal support tools which can be modified to suit various domains rather than single purpose legal expert systems, we focus on principles behind developing legal knowledge based systems. The original domain chosen was theAccident Compensation Act 1989 (Victoria, Australia), which relates to the provision of benefits for employees injured at work. For various reasons, which are indicated in the paper, we changed our domain to that ofCredit Act 1984 (Victoria, Australia). This Act regulates the provision of loans by financial institutions.The rule based part of our system which provides advice on the Credit Act has been commercially developed in conjunction with a legal firm. We indicate how this work has lead to the development of a methodology for constructing rule based legal knowledge based systems. We explain the process of integrating this existing commercial rule based system with the case base reasoning and retrieval architecture.     

Deduction graphs: an algorithm and applications

A deduction graph (DG) for logically deducing a new functional dependency (FD) or function-free Horn formula (extended from Horn clauses) from a subset of a given FDs or function-free headed Horn clauses in a relational database or rule-based expert systems is defined. An algorithm with a polynomial time complexity for constructing a DG based on a number of rules is designed. Applications of DGs to relational databases, rule-based expert systems, logic programming, and artificial intelligence are investigated. In addition to graphically solving the inference problem by DGs, many logic queries can be answered by DGs with substitutions for unifying expressions     

Industrial maintenance decision-making: A systematic literature review

The increasing competition among industries has leveraged the emergence of various tools and methods for maintenance decision-making support. This paper identifies in literature the application areas of industrial maintenance decision-making, the relationships between these areas and the ways in which authors integrate tools and methods. This information makes it possible to identify trends and deficiencies in this context, helping to centralize the efforts required for future work. This work follows a series of structured steps for a systematic literature review of papers related to the main topic available in online databases. The selected papers are subject to a content assessment and grouped according to the application areas. The direct comparison between these areas and the construction of a relational matrix provide a quantitative interpretation of the results and well-structured information. Additionally, this paper proposes a framework based on information from the literature, which summarizes the origin and flow of information used in the development of models, showing the relationship among application areas of decision making. The research undertaken identifies trends focused on joint production systems optimization and increasing the deployment of methods for autonomous equipment predictions.     

Storing and querying fuzzy XML data in relational databases

Information imprecision and uncertainty exist in many real-world applications and for this reason fuzzy data management has been extensively investigated in various database management systems. Currently, introducing native support for XML data in relational database management systems (RDBMs) has attracted considerable interest with a view to leveraging the powerful and reliable data management services provided by RDBMs. Although there is a rich literature on XML-to-relational storage, none of the existing solutions satisfactorily addresses the problem of storing fuzzy XML data in RDBMs. In this paper, we study the methodology of storing and querying fuzzy XML data in relational databases. In particular, we present an edge-based approach to shred fuzzy XML data into relational data. The unique feature of our approach is that no schema information is required for our data storage. On this basis, we present a generic approach to translate path expression queries into SQL for processing XML queries.     

Ultrawrap: SPARQL execution on relational data

The Semantic Web’s promise of web-wide data integration requires the inclusion of legacy relational databases,¹ i.e. the execution of SPARQL queries on RDF representation of the legacy relational data. We explore a hypothesis: existing commercial relational databases already subsume the algorithms and optimizations needed to support effective SPARQL execution on existing relationally stored data. The experiment is embodied in a system, Ultrawrap, that encodes a logical representation of the database as an RDF graph using SQL views and a simple syntactic translation of SPARQL queries to SQL queries on those views. Thus, in the course of executing a SPARQL query, the SQL optimizer uses the SQL views that represent a mapping of relational data to RDF, and optimizes its execution. In contrast, related research is predicated on incorporating optimizing transforms as part of the SPARQL to SQL translation, and/or executing some of the queries outside the underlying SQL environment.Ultrawrap is evaluated using two existing benchmark suites that derive their RDF data from relational data through a Relational Database to RDF (RDB2RDF) Direct Mapping and repeated for each of the three major relational database management systems. Empirical analysis reveals two existing relational query optimizations that, if applied to the SQL produced from a simple syntactic translations of SPARQL queries (with bound predicate arguments) to SQL, consistently yield query execution time that is comparable to that of SQL queries written directly for the relational representation of the data. The analysis further reveals the two optimizations are not uniquely required to achieve a successful wrapper system. The evidence suggests effective wrappers will be those that are designed to complement the optimizer of the target database.     

基于工程决策的专家系统模型设计与研究

工程决策的影响因子和参数繁多且复杂,为提高工程决策的可用性和准确性提出基于工程决策的专家系统模型。模型根据现有数据模型结合实际需求,在关系数据内部形成知识支撑环境模型,采用框架和产生式规则相结合的方法,将推理过程与专家知识库结合,并提出一种综合评估方法为支持,辅助生产方案设计和措施调整。以油田实际生产现状为例,给出了相应油田异常井措施调整方案的推理过程,完成了模型的实例设计和实现,达到了提供辅助决策以提高决策可用性和准确性的目的。     

Semantic integrity support in SQL:1999 and commercial (object-)relational database management systems

The correctness of the data managed by database systems is vital to any application that utilizes data for business, research, and decision-making purposes. To guard databases against erroneous data not reflecting real-world data or business rules, semantic integrity constraints can be specified during database design. Current commercial database management systems provide various means to implement mechanisms to enforce semantic integrity constraints at database run-time. In this paper, we give an overview of the semantic integrity support in the most recent SQL-standard SQL:1999, and we show to what extent the different concepts and language constructs proposed in this standard can be found in major commercial (object-)relational database management systems. In addition, we discuss general design guidelines that point out how the semantic integrity features provided by these systems should be utilized in order to implement an effective integrity enforcing subsystem for a database. Received: 14 August 2000 / Accepted: 9 March 2001 / Published online: 7 June 2001     

SEEKER:基于关键词的关系数据库信息检索

传统上,SQL是存取关系数据库中数据的主要界面.但是,对于没有经验的用户来说,学习复杂的SQL语法是一件困难的事情.实现基于关键词的关系数据库信息检索,将使用户不需要任何SQL语言和底层数据库模式的知识,用搜索引擎的方式来获取数据库中的相关数据.描述了一个基于关键词的关系数据库信息检索系统SEEKER的设计和实现.现有的关系数据库关键词查询系统只能检索关系数据库中的文本属性,而SEEKER还可以检索数据库元数据以及数字属性.并且,SEEKER采用了更合理的排序公式,支持Top-k查询.实验结果显示,SEEKER具有良好的查询性能.     

A legal expert system prototype integrated with databases

Legal expert systems have great potential in the environment protecton area. A system called ELP (Environmental Legal Protection) Advisor was created to provide information and references to legal authorities in the domain of legal protection of the environment. This paper describes the efforts of this expert system to date and its integration with environmental databases.     

Extended relational operators for statistical data manipulations in medical databases

Conventional relational database management systems fail to address three features of statistical data management in a biomedical/clinical database, namely, that (1) statistical and medical data (SMD) require a great deal of space and need to be stored in a reduced form with minimal duplication; indeed, SMD have many derived/calculated and summary statistics that make the number of attributes in a relation (i.e., a set of records) grow rapidly and dynamically; (2) most SMD have hierarchical structures that are difficult to manage using the relational data model since SMD are stored in separate relations for duplication and space considerations; and (3) the management of SMD is made easier if it is possible to reorganize relations or group data, a capability lacking in conventional relational database management systems. In this paper, we (1) introduce five extended relational operators, (lattice) NEST, (lattice) UNNEST, MERGE, SPREAD, and GEN, to reorganize relations; (2) integrate the extended operators with conventional relational algebra and introduce the concept of the lattice relational model; and (3) give applications of the extended relational operators and the lattice relational model in solving the problems of statistical data manipulation in medical databases.     

FriendFeed如何使用MySQL存储无Schema数据

如何不断增加新功能,不断更新底层的数据库结构和数据库中存储的数百万条已有记录,还要同时支持新旧功能。FriendFeed给出他们对这些问题的答案。