Herbert Shiu

The XML Tree Model - toward an XML conceptual schema reversed from XML Schema Definition

XML Schema Definition (XSD) is the logical schemas of an XML model, but there is no standard format for the conceptual schema of an XML model. Therefore, we propose an XML Tree Model (XTM) as an XML conceptual schema for representing data semantics in a diagram, and also as an XML data model validator for confirming the data semantics required by users. An XTM consists of hierarchical nodes representing all the elements, and the data relationships among elements within the XSD. A rule-based algorithm and an information capacity with pre- and post-conditions are developed as the methodology for reverse engineering. The proposed algorithm consists of two rules: General Information Transformation and Data Semantic Recovering to construct an XTM. Users can draw an XTM with data relationships among elements as a result of the reverse engineering.

Facebook - education with social networking websites for teaching and learning

This paper is a study of using social networking websites, in particularly Facebook, for conducting courses as a replacement of expensive traditional electronic learning platforms. At the early stage of the Internet community, Internet users used electronic mail as the main communication mean. Although email is still the core way of communication in a convenient but off-line mode, other facilities were introduced, such as many Instant Messaging (IM) software applications like I-Seek-You (ICQ) and MSN, which enable people to communicate in a real-time mode. However, the communication between people was further enhanced to the next stage, when Facebook came to existence as a social networking website that supports many features. People do not only communicate with others, but also organize all kinds of interactions among them. Facebook provides rich features for organizing relationships. The framework of Facebook actually provides free of charge software that were provided by traditional electronic learning. This paper studies how people use Facebook for teaching and learning, together with recommendations provided.

An Interpreter Approach for Exporting Relational Data into XML Documents with Structured Export Markup Language

Almost all enterprises use relational databases to handle real time business operations and most need to generate various XML documents for data exchanges internally among various departments and externally with business partners. Exporting data in a relational database to an XML document can be considered a data conversion process. Based on the four approaches for data conversion: Customized program, Interpretive transformer, Translator generator, and Logical level translation, this paper proposes a new interpretive approach using Structured Export Markup Language SEML interpreter for converting relational data into XML documents. The frameworks and languages proposed by other researchers are neither generic nor able to generate arbitrary XML documents. Therefore, SEML interpreter is a simple, user friendly, and complete solution with a new mark-up language ? SEML ? for data conversion. The solution can be used as a generic tool for extracting, transforming, and loading ETL purposes. In other words, the SEML interpreter is a solution for relational databases similar to what X-Query is for XML databases.

Visualization of XML conceptual schema recovered from XML schema definition

XML Schema Definition (XSD) is in the logical level of XML model and is used in most web applications. At present, there is no standard format for the conceptual level of XML model. Therefore, we introduce an XML Tree Model as an XML conceptual schema for representing and confirming the data semantics according to the user requirements in a diagram. The XML Tree Model consists of nodes representing all elements within the XSD. We apply reverse engineering from an XSD to an XML Tree Model to assist end users in applying an XML database for information highway on the Internet. The data semantics recovered for visualization include root element, weak elements, participation, cardinality, aggregation, generalization, categorization, and n‐ary association, and which can be derived by analyzing the structural constraints of XSD based on its key features such as key, keyref, minOccurs, maxOccurs, Choice, Sequence and extension. We use the Eclipse user interface for generating a graphical view for XML conceptual ...

Reverse Engineering from an XML Document into an Extended DTD Graph

Extensible markup language (XML) has become a standard for persistent storage and data interchange via the Internet due to its openness, self-descriptiveness, and flexibility. This article proposes a systematic approach to reverse engineer arbitrary XML documents to their conceptual schema–extended DTD graphs?which is a DTD graph with data semantics. The proposed approach not only determines the structure of the XML document, but also derives candidate data semantics from the XML element instances by treating each XML element instance as a record in a table of a relational database. One application of the determined data semantics is to verify the linkages among elements. Implicit and explicit referential linkages are among XML elements modeled by the parent-children structure and ID/IDREF(S) respectively. As a result, an arbitrary XML document can be reverse engineered into its conceptual schema in an extended DTD graph format.

CONCURRENT DATA MATERIALIZATION FOR XML-ENABLED DATABASE WITH SEMANTIC METADATA

For a company with many databases in different data models, it is necessary to consolidate them into one interchangeable data model and present data in more than one data model concurrently to different users or individual users who need to access the data in more than one data model. The benefit is to let the user stick to his/her own data model to access database in another data model. This paper presents a semantic metadata to preserve database constraints for data materialization to support the users view of database on an ad hoc basis. The semantic metadata can store the captured semantics of a relational or an XML-enabled database into classes. The stored constraints and data can be materialized into a target database upon user request. The user is allowed to perform data materialization many times alternatively. The process can provide a relational as well as an XML view to the users simultaneously. This concurrent data materialization function can be applied into data warehouse to consolidate heterogeneous database into a fact table in a data model of users choice. Furthermore, a user can obtain either a relational view or an XML view of the same dataset of an XML-enabled database interchangeably.

Long distance learning for under-developing countries using replicated XML database system

Education can improve the quality and production of the people in a country in a long run, which is especially important in under developed countries. Besides, there illiteracy rates in remote districts in People Republic of China are still high. Deficient transportation and communication are common in these areas, and it is therefore necessary to resolve these two critical issues. As education involves exchanging large amount of teaching materials, such as course materials, assignments, questions and answers, between educators and learners, XML is a preferable document format for these materials and XML database is therefore a preferable storage and retrieval facility. For remote districts, it is preferable to have regional offices that handle the teaching materials, and each regional office should be equipped with an XML database and the entire education framework is supported by XML databases installed in the university, the regional offices and student machines, and the document exchanges are to be implemented by replication. This paper addresses the issues related to supporting long distance learning by resolving the communication and transportation problem with a loosely connected XML database system with replication.