A Knowledge-Based Web Information System for the Fusion of Distributed Classifers

This chapter presents the design and development of WebDisC, a knowledge-based web information system for the fusion of classifiers induced at geographically distributed databases. The main features of our system are: (i) a declarative rule language for classifier selection that allows the combination of syntactically heterogeneous distributed classifiers; (ii) a variety of standard methods for fusing the output of distributed classifiers; (iii) a new approach for clustering classifiers in order to deal with the semantic heterogeneity of distributed classifiers, detect their interesting similarities and differences, and enhance their fusion; and (iv) an architecture based on the Web services paradigm that utilizes the open and scalable standards of XML and SOAP.

Web Information Extraction via Web Views

With the explosion of information on the Web, traditional ways of browsing and keyword searching of information over web pages no longer satisfy the demanding needs of web surfers. Web information extraction has emerged as an important research area that aims to automatically extract information from target web pages and convert them into a structured format for further processing. The main issues involved in the extraction process include: (1) the definition of a suitable extraction language; (2) the definition of a data model representing the web information source; (3) the generation of the data model, given a target source; and (4) the extraction and presentation of information according to a given data model. In this chapter, we discuss the challenges of these issues and the approaches that current research activities have taken to revolve these issues. We propose several classification schemes to classify existing approaches of information extraction from different perspectives. Among the existing works, we focus on the Wiccap system — a software system that enables ordinary end-users to obtain information of interest in a simple and efficient manner by constructing personalized web views of information sources.

Structural Media Types in the Development of Data-Intensive Web Information Systems

In this chapter, a conceptual modeling approach to the design of web information systems (WIS) will be outlined. The notion of media type is central to this approach. Basically, a media type is defined by a view on an underlying database schema, which allows us to transform the data content of a database into a collection of media objects that represent the data content presented at the web interface. The view is extended by operations and an adaptivity mechanism, which permits the splitting of media objects into several smaller units in order to adapt the WIS to different user preferences, technical environments and communication channels. The information entering the design of media types is extracted from a previous story boarding phase. In consecutive phases, media types have to be extended by style patterns as the next step toward implementation.

Indexing Techniques for Web Access Logs

Access histories of users visiting a web server are automatically recorded in web access logs. Conceptually, the web-log data can be regarded as a collection of clients’ access-sequences, where each sequence is a list of pages accessed by a single user in a single session. This chapter presents novel indexing techniques that support efficient processing of so-called pattern queries, which consist of finding all access sequences that contain a given subsequence. Pattern queries are a key element of advanced analyses of web-log data, especially those concerning typical navigation schemes. In this chapter, we discuss the particularities of efficiently processing user access-sequences with pattern queries, compared to the case of searching unordered sets. Extensive experimental results are given, which examine a variety of factors and illustrate the superiority of the proposed methods over indexing techniques for unordered data adapted to access sequences.

Traversal Pattern Mining in Web Usage Data

Web usage mining is to discover useful patterns in the web usage data, and the patterns provide useful information about the user’s browsing behavior. This chapter examines different types of web usage traversal patterns and the related techniques used to uncover them, including Association Rules, Sequential Patterns, Frequent Episodes, Maximal Frequent Forward Sequences, and Maximal Frequent Sequences. As a necessary step for pattern discovery, the preprocessing of the web logs is described. Some important issues, such as privacy, sessionization, are raised, and the possible solutions are also discussed.

Storage and Access Control Issues for XML Documents

XML documents management is becoming an area of great research value and interest since XML has become a popular standard for data communication and knowledge exchange over the Internet. Therefore, new issues have emerged in terms of storage and access control policies for XML documents. Concerning the storage issues, the majority of proposals rely on the usage of typical database management systems (DBMSs), whereas XML documents can also be stored in other storage environments (such as file systems and LDAP directories). It is important to consider storage and access control together since these issues are essential in implementations for XML documents management. Moreover, the chapter focuses on the recent access control models which guarantee the security of the XML-based data, which are located in a variety of storage topologies. This chapter’s goal is to survey and classify existing approaches for XML documents storage and access control, and, at the same time, highlight the main differences between them. The most popular XML database software tools are outlined in terms of their storage and access control policies.

Transformation of XML Schema to Object Relational Database

XML (eXtensible Markup Language) is fast emerging as the dominant standard for describing data and interchanging data between various systems and databases on the Internet. It offers the XML schema definition language as formalism for defining the syntax and structure of XML documents, providing rich facilities for defining and constraining the content of XML documents. Nevertheless, to enable efficient business application development in large-scale e-commerce environments, XML needs to have databases to keep all the data. Hence, it will inevitably be necessary to use methods to describe the XML schema in the Object-Relational Database (ORDB) formats. In this chapter, we present the way to transform the XML encoded format, which can be treated as a logical model, to the ORDB format. The chapter first discusses the modeling of XML and why we need the transformation. Then, a number of transformation steps from the XML schema to the Object-Relational Logical model and XML to ORDB are presented. Three perspectives regarding this conceptual relationship (aggregation, association and inheritance) and their transformations are mainly discussed.

Toward a Model of the Migration of Communication Between Media Devices

The ever-increasing volume of information generated by humanity has been supported by our ability to invent devices that record, store, retrieve and communicate this information in a variety of media, presented by a variety of devices. Since new media devices are continually emerging, and each device has different utility, it is possible that a great deal of information will need to be migrated between media devices in order to take advantage of their utility. While computer programs that perform migration automatically would help to process the potential volume of information being migrated, such programs will require a model of the migration of communication between media devices. In this chapter, we propose such a model that is based on ideas from information theory and media modeling. The model represents a number of interacting components including: the dimensions and utility of the media device; the media of and structure of communication; and conversion functions between media devices. We evaluate it by applying it theoretically to one of the important tasks in digital libraries: the digitisation (migration) of a set of highly structured textbooks to hypertext. We argue that emerging web-technologies could assist the automatic migration of communication between media devices as long as specific components of the migration model are present in the information. Applications of this model lie in the preservation of digital libraries, which must be able to migrate between media devices in order to be immune to degradation and technological obsolescence.

A Practical Approach to the Derivation of a Materialized Ontology View

The success of the semantic web depends largely on how well ontologies can be utilized and formulated. Interoperability between systems using different versions of the same ontology is essential, and this implies the need for a regulated derivation of materialized ontology views (which can be considered a modified version of an ontology). This chapter applies the formalisms for such a derivation process to a practical example, emphasizing the possibility for automation, and also for optimization, to develop a high-quality derived ontology.

Story Boarding for Web-Based Information Systems

The present chapter is about story boarding for web information systems (WIS). It is a holistic usage-centered approach for analyzing requirements and conceptual modeling of WIS. We conceptualize web information systems as open information systems and discuss them from a business point of view, including their linguistic, communicational and methodological foundations. To illustrate story boarding, we discuss a simple application example.