Judul: Evaluasi penggunaan Similarity Thesaurus terhadap ekspansi kueri dalam sistem temu kembali informasi berbahasa Indonesia
Abstrak: Istilah merupakan komponen utama dalam sistem temu kembali informasi. Penggunaan istilah sebagai indeks dan kueri sangat mempengaruhi kinerja dari suatu sistem temu-kembali informasi. Penelitian ini mengamati pengaruh penggunaan similarity i'hesaurus dalam mernbantu proses ekspansi kueri terhadap kinerja sistem temu kembali informasi berbahasa Indonesia. Dengan menggunakan 30 gugus kueri pada 1.000 dokumen di koleksi dilakukan uji banding antara pemberian bobot yang sama dan yang berbeda terhadap istilah daiam kueri untuk melihat pengmhnya terhadap hasil temu kembali sebelum dan setelah melakukan ekspansi kueri. Dengan memanfaatkan cosir~es ebagai ukuran kesamaan dan bobot istila11 dalam kueri, ditentukan istilah-istilah yang akan digunakan dalam ekspansi kueri. Dalam ha1 ini, ada dua perlakuan yang dilakukan terhadap jumlah istilah yang diambil, yaitu dengan mengambil 5 (TH5) dan 10 (THIO) istilah yang memiIiki nilai kesamaan terbesar dengan kueri. Setelah dibandingkan dengan hasil ternu kembali tanpx ekspansi kueri (Now diperoIeh bahwa penggunaan similarity thesalrnrs secara keseluruhan meningkatkan kinerja sistem temu kembali informasi. Namun, hd ini tidak sepenuhnya berlaku sebab sangat dipengaruhi oleh bobot istilah di dalam kueri. Setelah dibandingkan kinerja sistem pada tiga percobaan, yaitu Eanpa thesaurlis (NoTEI) dm dengan thesazirus (TH5 atau THIO) untuk bobot istilah dalam kueri yang berbeda (1 dm idf) diperoleh bahwa penggunaan idf sebagai bobot istilah dalam kueri meningkatkan kinerja sistem, baik dalam ha1 temu kembali biasa maupun ekspansi kueri. Sebaliknya penggunaan 1 sebagai bobot istilah ddam kueri justru menurunkan kinerja sistem. Kata kunci : temu kembali informasi, ekspansi kueri, similarity thesawus.
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Judul: Ekspansi Kueri pada Sistem Temu Kembali Informasi Berbahasa Indonesia Menggunakan Thesaurus
Abstrak: Query expansion is a common technique for fixed query in order to yield a better information retrieval result. Using a thesaurus is a way for fixed query. Thesaurus is a dictionary of words and terms which are collected and filtered by correlation of meaning of the word, like synonim, antonim, hyponim, and hypernim. This research is intended to analyze the effectivity of query expansion using thesaurus Global Analysis Method. There are a thousand agricultural documents and 93 medical plants documents. The research used Tf-Idf as a weighting method. The result of system performance which were used in this research is good with average precision of 53% for agricultural document and 76% for medical plants document using thesaurus query expansion. The maximal result that the thesaurus could gain is by using two-word length query. Query expansion method using thesaurus has a better result than the one using 2-language dictionary and pseudo relevance feedback document segmentation. The query length and the taking of some number of word group in thesaurus will affect the result of information retrieval.
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Judul: Photovoltaic Effect In A CdS/P3HT-Chitosan Junction
Abstrak: A CdS/Polymer junction has been fabricated and it’s photovoltaic effect has been studied. The polymer is a blend of poly-3hexyltiophene (P3HT), chitosan and polyethileneglicol (PEG). Boron in situ doping of CdS using Chemical Bath Deposition (CBD) was investigated. The effect of B-doping and annealing on optical properties as well as on electrical and morphology of CdS film were studied. The structure and morphology of the film were detected by XRay Diffraction (XRD) and Scanning Electron Microscopy (SEM). The polymer film was sandwiched between the CdS semiconductor and an ITO glass to form an ITO/CdS/Polymer/ITO photovoltaic cell. Time constant (τ) and open circuit voltage (Voc) were investigated by using voltage censor. The bandgap of films were determined using absorbance edge method. The results of annealing optical bandgap of undoped CdS shifted from 2,49 eV down to 2,39 eV. Phase transition of CdS due to annealing temperature and induced lattice damage due to doping. The room temperature conductivity of polymer is 3,8 – 6,6 x 10-7 S/cm as function of frequency between 100 – 5000 Hz. The Voc of the fabricated cells ranges between 107 – 286 mV and time constant ranges between 2,5 to 43,75 s.
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