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Michael Lesk: Chief Scientist, Bellcore
No full textA brief summary of the presentation given by Michael Lesk, Chief Scientist, Bellcore, and author of Practical Digital Libraries (1997) at the 17th annual ACRL/NY symposium, held on November 21, 1997
Word Sense Disambiguation dengan Algoritma Lesk (Simplified Lesk)
Get PDFAmbiguitas makna pada kalimat bahasa inggris adalah gejala terjadinya tafsiran lebih dari satu makna. Hal ini dapat terjadi baik dalam ujaran lisan maupun tulisan. Tafsiran lebih dari satu ini dapat menimbulkan keraguan dan kebingungan dalam mengambil keputusan tentang makna yang dimaksud. Untuk menaggulangi permasalahan ini digunakan metode pencarian makna terhadap kata ambigu pada kalimat bahasa inggris dengan menggunakan algoritma simplified lesk. Algoritma ini digunakan karena kesederhanaannya dalam menentukan makna ambigu, yaitu menghitung jumlah kesamaan kata antara konteks kalimat dengan gloss (definisi) makna kata ambigu beserta examples (contoh) kalimat yang diambil dari WordNet. Algoritma ini digunakan untuk menentukan makna kata ambigu pada masing-masing kalimat yang terdapat pada sample dataset yang telah disediakan sebanyak 100 kalimat bahasa inggris. Kemudian evaluasi dilakukan dengan tujuan mencari precision, recall, f-measure dan accuracy dari algoritma simplified lesk. Dari hasil evaluasi didapatkan precision dari algoritma simplified lesk adalah 46,5%, recall 40%, f-measure 43% dan accuracy 47%
Probing Protein-structure By Solvent Perturbation of Nmr-spectra .2. Determination of Surface and Buried Residues In Homologous Proteins
No full textThe experimental assignment of most residues in a protein to the surface or interior is in principle possible without prior solution of a complete three-dimensional structure. The method described is based on nmr measurements that determine the amino acid composition of the surface of a protein [A. Petros, L. Mueller, and K. D. Kopple (1990) Biochemistry, Vol. 29, pp. 10041-10048; G. Esposito, A. M. Lesk, H. Molinari, A. Motta, N. Niccolai, and A. Pastore (1992) Journal of Molecular Biology, Vol. 224, pp. 659-670]. If these measurements are carried out on several homologous proteins of known sequence, it is possible to combine the results to determine, in most cases, which positions in the sequence contain exposed residues
Empirical results of e-Lesk for three different window sizes.
No full textEmpirical results of e-Lesk for three different window sizes.</p
Evaluating variants of the lesk approach for disambiguating words
No full textThis paper presents a detailed analysis of the factors determining the performance of Lesk-based word sense disambiguation methods. We conducted a series of experiments on the original Lesk algorithm, adapted to WORDNET, and on some variants. These methods were evaluated on the test corpus from SENSEVAL2, English All Words, and on excerpts from SEMCOR. We designed a fine grain analysis of the answers provided by each variant in order to better understand the algorithms than by the mere precision and recall figures. 1
Comparison of the structures of globins and phycocyanins: Evidence for evolutionary relationship
No full textGlobins and phycocyanins are two classes of proteins with different function, different ligands, and no substantial sequence similarity, yet the conformations of their polypeptide chains show very similar folding patterns. Does this arise from a genuine, albeit very distant, evolutionary relationship, or does it represent a common solution of a structural problem? We address this question by a very detailed comparison of the structures of the two protein families. An analysis of the helices and their interactions shows many features common to globins and phycocyanins, including some exceptional features of the globins such as a 3-10 C helix and the unusual "crossed-ridge" packing pattern at the B/E helix interfaces. We conclude that the evidence supports the hypothesis of distant evolutionary relationship between globins and phycocyanins
Three-dimensional searching for recurrent structural motifs in databa- ses of protein structures.
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