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Dagstuhl Seminar 99371

Declarative Data Access on the Web

( Sep 12 – Sep 17, 1999 )

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Please use the following short url to reference this page: https://www.dagstuhl.de/99371

Organizers
  • G. Vossen (Münster)
  • K. Vidyasankar (Newfoundland)
  • N. Spyratos (Paris)



Motivation

Today, information is spreading to all sectors of society in ever increasing volumes. This information comes in multimedia digital form and is transmitted over world-wide networks. In particular, the World-Wide Web (WWW) renders it possible to obtain information that is distributed over the entire Internet. Since the Web (and the number of its users) continues to grow at a high speed, adequate tools are needed for finding, storing, and structuring the vast amount of information offered; for locating, retrieving, and presenting the information to the final user; for aiding the end-user in customizing the information obtained for personal usage. Although technology is advancing fast (e.g., Web browsers built into cellular phones), a lot remains to be done concerning the efficient retrieval of information from large digital collections (often called digital libraries), and its intelligible presentation to the end user.

From a database perspective, the information provided by the Web can be perceived as a huge, heterogeneous database which is distributed world-wide, and which is accessed by multiple users. From this point of view, it appears reasonable to try to adopt concepts and techniques from database technology and in particular from the area of information retrieval (IR) to the context of the Web. It makes sense to investigate to what extent they are applicable to a large-scale database such as the Web, or what kind of generalizations, extensions, or completely novel developments become necessary. Motivation to do so is obtained from a look at the present situation. Indeed, when accessing data sources on the Web with current browser and search-engine technology, a number of issues arise which deserve further study; these include:

  1. Locating the source: Today's search engines are "primitive" devices for performing searches simply because they rarely do content-based retrieval; this in particular applies to search engines such as AltaVista, Fireball, Lycos, Yahoo!, and others. Instead, they mostly rely on searching indexes or directories, where distinct strategies in handling index information are exploited.
  2. Retrieving relevant information: Once a desired data source has been located, the issue of retrieving relevant data arises. Two factors are important in this respect: the structure of the data, i.e., data can be anywhere between highly structured and totally unstructured, and the multimedia nature of data.
  3. Organizing retrieved data for personal usage: Once data has been retrieved, it most likely needs to be reorganized for easy use in the applications the end-user has in mind. Often, data obtained from the Web is kept in a customized database for personal usage.

Even in the restricted and simple case that a user accesses a single data source through the Web, all these issues described above may arise. When multiple sources are accessed, the additional problem of combining and integrating information from these different sites comes up. As the information available through the Web becomes more and more complex and voluminous, the importance of providing adequate, application-oriented interfaces becomes a decisive factor. Indeed, users of cellular phones, office computers, or GPS-based navigation systems in cars, to name just a few, have vastly different requirements to their Web interfaces, ranging from simple textual to multimedia output. Considering the various environments from which information can be accessed (including mobile ones), the need to adapt interfaces to these environments arises. For example, an SQL query can hardly be expressed on the interface of a pager that provides one line of text only; on the other hand, a multimedia office computer can easily accommodate more sophisticated query facilities than SQL.

The goal of this seminar is to study the problems of locating, retrieving, and presenting information on the Web from a database perspective with an emphasis on SQL-like declarative languages and their interaction with information retrieval techniques, and the impact of this interaction on user interfaces.


Participants
  • G. Vossen (Münster)
  • K. Vidyasankar (Newfoundland)
  • N. Spyratos (Paris)