tailieunhanh - Báo cáo hóa học: " A Data-Driven Multidimensional Indexing Method for Data Mining in Astrophysical Databases"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: A Data-Driven Multidimensional Indexing Method for Data Mining in Astrophysical Databases | EURASIP Journal on Applied Signal Processing 2005 15 2514-2520 2005 Hindawi Publishing Corporation A Data-Driven Multidimensional Indexing Method for Data Mining in Astrophysical Databases Marco Frailis Dipartimento di Fisica Universita degli Studi di Udine Via delle Scienze 208 33100 Udine Italy Email frailis@ Alessandro De Angelis INFN Sezione di Trieste Gruppo Collegato di Udine Via delle Scienze 208 33100 Udine Italy Email de angelis@ Vito Roberto Dipartimento di Matematica e Informatica Universita degli Studi di Udine Via delle Scienze 208 33100 Udine Italy Email roberto@ Received 1 June 2004 Revised 2 March 2005 Large archives and digital sky surveys with dimensions of 1012 bytes currently exist while in the near future they will reach sizes of the order of 1015. Numerical simulations are also producing comparable volumes of information. Data mining tools are needed for information extraction from such large datasets. In this work we propose a multidimensional indexing method based on a static R-tree data structure to efficiently query and mine large astrophysical datasets. We follow a top-down construction method called VAMSplit which recursively splits the dataset on a near median element along the dimension with maximum variance. The obtained index partitions the dataset into nonoverlapping bounding boxes with volumes proportional to the local data density. Finally we show an application of this method for the detection of point sources from a gamma-ray photon list. Keywords and phrases multidimensional indexing VAMSplit R-tree nearest-neighbor query one-class SVM point sources. 1. INTRODUCTION At present several projects for the multiwavelength observation of the universe are underway for example SDSS GALEX POSS2 DENIS and so forth 1 . In the next years new spatial missions will be launched . GLAST Swift 2 3 surveying the wall sky at different wavelengths gammaray X-ray optical . In the astroparticle and .