Search results for "Mapper"
showing 3 items of 33 documents
Comparaison de deux méthodes de correction atmosphérique des données thermiques de Landsat TM
1996
The high resolution of Landsat Thematic Mapper (TM) thermal infrared data can be interesting in applications such as energy balance and crop water stress studies. However, surface temperature measurements are strongly affected by atmospheric effects, particularly by water vapour absorption, therefore a correction method is absolutely necessary. The impossibility of applying a split-window equation and the difficulty of having temporarily coincident radiosondes produce a slight use of Landsat TM data to obtain surface temperature. Vidal et al. show that in a zone with homogeneous climatic conditions, atmospheric correction can be evaluated by using energy balance equation and standard meteor…
Perfect Hashing Structures for Parallel Similarity Searches
2015
International audience; Seed-based heuristics have proved to be efficient for studying similarity between genetic databases with billions of base pairs. This paper focuses on algorithms and data structures for the filtering phase in seed-based heuristics, with an emphasis on efficient parallel GPU/manycores implementa- tion. We propose a 2-stage index structure which is based on neighborhood indexing and perfect hashing techniques. This structure performs a filtering phase over the neighborhood regions around the seeds in constant time and avoid as much as possible random memory accesses and branch divergences. Moreover, it fits particularly well on parallel SIMD processors, because it requ…
Eksperimenti ar topoloģisko datu analīzi
2022
Maģistra darba mērķis ir iepazīstināt ar topoloģisko datu analīzi, kas ir pieeja datu kopu analīzei, izmantojot topoloģijas, kā matemātikas novirziena, metodes. Šī inovatīvā datu analīzes metode pasaulē pēdējos gados strauji attīstās un ar vien plašāk tiek pielietota, lai iegūtu informāciju no sarežģītiem, liela apjoma, daudzdimensionāliem datiem. Pašreiz nekur nav atrodams topoloģiskās datu analīzes apraksts un pielietojamība, latviešu valodā. Darbā tiek apskatīti divi dažādi uz topoloģiskās datu analīzes balstīti algoritmi - Mapper un ToMATo, kuru veiksmīgā izmantošanā noteicošais ir pareizu parametru izvēle. Darbā tiek pētītas un piedāvātas šo algoritmu parametru optimizācijas metodes un…