Tomáš Skopal

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The Signature Quadratic Form Distance on feature signatures represents a flexible distance-based similarity model for effective content-based multimedia retrieval. Although metric indexing approaches are able to speed up query processing by two orders of magnitude, their applicability to large-scale multimedia databases containing billions of images is(More)
Multi-dimensional data structures are applied in many real index applications, i.e. data mining , indexing multimedia data, indexing non-structured text documents and so on. Many index structures and algorithms have been proposed. There are two major approaches to multi-dimensional indexing. These are, data structures to indexing metric and vector spaces.(More)
BACKGROUND Similarity search in protein databases is one of the most essential issues in computational proteomics. With the growing number of experimentally resolved protein structures, the focus shifted from sequences to structures. The area of structure similarity forms a big challenge since even no standard definition of optimal structure similarity(More)
In the area of multidimensional databases, the UB-tree represents a promising indexing structure. A key feature of any multidimen-sional indexing structure is its ability to effectively perform the range queries. In the case of UB-trees, we have proposed an advanced range query algorithm making possible to operate on indices of high dimension-ality. In this(More)
The Universal B-tree is a data structure for multidimen-sional data indexing. In this paper we introduce a new algorithm of processing the range query in UB-trees. This algorithm performs very well, especially in high-dimensional indexes and thus significantly reduces influence of the " curse of dimensionality ". We explain the algorithm using a geometric(More)
An important research issue in multimedia databases is the retrieval of similar objects. For most applications in multimedia databases, an exact search is not meaningful. Thus, much effort has been devoted to develop efficient and effective similarity search techniques. A recent approach that has been shown to improve the effectiveness of similarity search(More)
Similarity search and content-based retrieval have become widely used in multimedia database systems that often manage huge data collections. Unfortunately, many effective content-based similarity models cannot be fully utilized for larger datasets, as they are computationally demanding and require massive parallel processing for both feature extraction and(More)
This article presents ACB – high efficient text compression method, its word-based modification and finally discuss relating benefits by creating auxiliary query subsystem for usage in text retrieval systems. 1 Compression and Indexing in TRS Data compression is widely used in text (or full-text) databases to save storage space and network bandwidth. In(More)