Jirí Walder

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Data compression has been widely applied in many data processing areas. Compression methods use variable-length codes with the shorter codes assigned to symbols or groups of symbols that appear in the data frequently. There exist many coding algorithms, e.g. Elias-delta codes, Fibonacci codes and other variable-length codes which are often applied to(More)
Multi-dimensional data structures have been widely applied in many data management fields. Spatial data indexing is their natural application, however there are many applications in different domain fields. When a compression of these data structures is considered, we follow two objectives. The first objective is a smaller index file, the second one is a(More)
N-grams are applied in some applications searching in text documents, especially in cases when one must work with phrases, e.g. in plagiarism detection. N-gram is a sequence of n terms (or generally tokens) from a document. We get a set of n-grams by moving a floating window from the begin to the end of the document. During the extraction we must remove(More)
Data compression has been widely applied in many data processing areas. Compression methods use variable-length codes with the shorter codes assigned to symbols or groups of symbols that appear in the data frequently. Fibonacci code, as a representative of these codes, is often utilized for the compression of small numbers. Time consumption of encoding as(More)
In this article, we deal with the problem of general matching of two images taken by a camera. To find the correspondence between two images, we use the multiresolution wavelet analysis of the image functions. The wavelet analysis is good at scale adaptivity and, therefore, very effective in general image matching. We test various wavelet functions, and(More)
The R-tree is one of the most popular multidimensional data structure. This data structure bounds spatially near points in multidimensional rectangles and supports various types of queries, e.g. point and range queries. When a compression of the data structure is considered, we follow two objectives. The first objective is a smaller index file and the(More)
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