Completed Projects

Data Mining and Knowledge Discovery

The amount of information that is being created and stored in the computer is increasing very rapidly. Everyday transactions, protocols, and documents are being stored in the computer and automated monitoring systems create vast information repositories. With the advent of the internet, these information resources have become available to individuals and companies regardless of national borders and constraints of time and space. As a consequence, information overload is rapidly becoming the new plague of the information society. It is, therefore, becoming increasingly important to provide effective tools to help users organize, manage, understand, and access large repositories of information.

High-Dimensional Indexing

In many application domains we have to deal with high-dimensional data sets. When searching high-dimensional data spaces, the so-called curse of dimensionality leads to a deterioration of the performance of classic indexing structures. We analyse typical effects present in high-dimensional data spaces, propose an advanced index structure for HD data, and present an accurate cost model for estimating access costs and optimizing indices when searching HD indices.

Visualization of Large Databases

Never before in history data has been generated at such high volumes as it is today. Exploring and analyzing the vast volumes of data becomes increasingly difficult. Information visualization and visual data mining can help to deal with the flood of information. The advantage of visual data exploration is that the user is directly involved in the data mining process. There is a large number of information visualization techniques which have been developed over the last decade to support the exploration of large data sets.

Pattern- and DataBase Management Systems

The increasing amount of complex information is posing requirements for today's and tomorrow's Database Management Systems. Such information possesses a number of key features such as huge volume of data, diversity and complexity. These novel information types can be represented by patterns.

Similarity Search in Multimedia Databases

A multimedia database is a system able to store and retrieve objects made up of text, images, sounds, animations, voice, video, etc. The wide range of applications for MMDBs leads to a number of different problems with respect to traditional database systems, which only consider textual and numerical attributes. These problems include among other things the querying and retrieving of multimedia objects.

Similarity Search in Spatial Databases

Spatial databases contain multidimensional data with explicit knowledge about objects, their extent, and their position in space. These objects are usually represented in some vector-based format, and their relative positions may be explicit or implicit (i.e., derivable from the internal representation of their absolute positions). This research field addresses the similarity search in this kind of databases.

Large Spatial Data and Cartography

Extracting knowledge from large spatial databases is crucial for the development of spatial database systems. Visual Data Mining applies human visual perception to the exploration of these large data sets.