Judul: Pembobotan RIDF pada Mesin Pencari Bahasa Indonesia untuk Ekspansi Kueri Menggunakan Analisis Konteks Lokal
Abstrak: Automatic query expansion is a technique for dealing with the fundamental issue of word mismatch between queries and documents in information retrieval. A number of approaches on query expansion have been studied, especially on techniques that analyze the corpus to discover word relationships (global technique) and those that analyze documents retrieved by initial query (local technique). Both techniques have their own advantages and limitations. Local context analysis is an automatic query expansion which is a combination of global and local techniques. The purpose of this research is to implement query expansion with local context analysis using TF (Term Frequency) RIDF (Residual Inverse Document Frequency) weighting method, a variation of IDF (Inverse Document Frequency) that assigns weights to terms according to the difference between the logs of the actual IDF and its prediction by Poisson model. The obtained performance of information retrieval was 15% average precision. The results also showed that the number of top-ranked documents and passages did not significantly affect the average precision. The more influential factor was the number of query expansions.
Keyword: 

Judul: Ekspansi Kueri pada Sistem Temu Kembali Informasi Berbahasa Indonesia menggunakan Kamus Dwibahasa
Abstrak: The most frequent problem on information retrieval is the users inability in representing information they need, in a query form. Thus, one of the solutions to overcome such situation is by applying query expansion technique. By applying the method, query will be expanded, and the new query produced will be used to do the search task. One of the approaches in determining the term of the expansion is Translation with Bilingualism Dictionary, which works through query translation process using dictionary, and the calculation of weight from each expanded candidate terms. In order to increase the relevance of the search result, this research uses Translation with Bilingualism Dictionary as the method to apply. Acknowledging the influence of the method, the research trial and error through the observation of the eleven recall precision number is applied to the produced retrieval result by using different expansion terms. Based on the observation of the produced precision number, it is identified that the use of Translation method in this research has not been successfull in increasing the relevance of the search results. The more expansion terms used, the smaller the precision number produced.
Keyword: 

Judul: Synthesis of Apatite - Chitosan Composite Using Duck Eggshell and Chitosan with Temperature and pH Control
Abstrak: Composite of apatite-chitosan was prepared by using chitosan as polymer matrix. Calcium phosphate was prepared from CaO and (NH4)2HPO4, which the ratio Ca : P had to be 1.67. Chitosan is produced by deacetilase from biopolymer chitin. Duck eggshell (95% CaCO3) as starting material was converted to be calcium oxide (CaO) through calcinations with temperature 1000oC for 5 hours. In-situ and ex-situ methods were prepared from apatite and chitosan (dissolved with acetate acid 2%). Calcium phosphate prepared for bone implantation, but it is too fragile and brittle to be implant into the body. So addition of chitosan can decrease crystalinity and increase mechanic characteristic (tougher). Composite apatite-chitosan was resulted by fast precipitation. Fast precipitation was held in a breaker glass with nitrogen atmosphere, under controlled temperature at 37oC and pH 7, in order to increase amount of hydroxyapatite. Precipitation with CaO which was dropped by (NH4)2HPO4. Hydroxyapatite and chitosan were appearing at samples with in-situ and ex-situ methods which indicating by peak matching of XRD (closed lattice parameter, crystal size), overlapping at FTIR spectra and supporting by SEM picture (homogenous and agglomerated particle). However, it still needs further research to examine biocompatibility osteoconductive degree of sample by in-vivo and in-vitro test.
Keyword: