Judul: Penggunaan Operator Belief Revision pada Temu Kembali Dokumen Bahasa Indonesia Model Boolean
Abstrak: Retrieval results of conventional Boolean Model are based only on the exact matching between document and query without ranking. Extended Boolean Model has developed a search process using partial matching and ranking, but it is difficult to be applied for complex queries structures. Belief Revision model was introduced to improve the information retrieved by Boolean Models. The objective of this research is to implement Extended Boolean Model (EBM) and Belief Revision (BR) to rank Indonesian documents. Query and document are weighted in binary. Then, the similarity is calculated to obtain the rank. Information retrieved using EBM equals to BR with average precision of 0.5148
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Judul: PUTRA. Extended Boolean Model on Retrieval Using P-Norm Model and Belief Revision
Abstrak: Extended Boolean Model is introduced to intermediate between the Boolean system of query processing and the vector-processing model. The query structure inherent in the Boolean system is preserved, while at the same time weighted term may be incorporated into both queries and stored documents. The retrieved output can also be ranked in strict similarity order with the user queries. Belief Revision is a logical framework in which documents and queries are represented by propositional formulas. Disjunctive Normal Form (DNF) is used to represent documents and queries in the Belief Revision. The purpose of this research is to implement Extended Boolean Model using P-Norm Model and Belief Revision for documents in Bahasa Indonesia. This testing used 30 queries from a thousand agricultural documents and 13 queries from 93 medicinal plants documents. The test result shows that the use of medicinal plants documents is better than agricultural documents. This is due to agricultural documents which have a high similarity between documents. The performance of information retrieval with P-Norm Model and Belief Revision gave good result which is around 81% average precision for medicinal plants documents and 54% for agricultural documents.
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Judul: Application of phycocyanin from microalgae Spirulina platensis as light harvesting in anatase TiO2 nanoparticle solar cell.
Abstrak: The dye sensitized solar cell (DSSC) has been assemblied used hybrid titanium oxide (TiO2) film/phycocyanin. The TiO2 film was synthesized by sol gel method with titanium chlorida (TiCl4) as precursor by hydrolysis used sulfuric acid (H2SO4). Furthermore, it calcinated for 2,5 hours in variation of annealing temperature (400oC, 600oC, 800oC, dan 1000oC). In XRD patterns exhibited which annealing temperature at 400oC to 800oC were anatase phase all. When annealed at temperature 1000oC, it caused phase transformation from anatase to rutile. The crystals size according to XRD patterns were 13,75 nm, 20,79 nm, 25,25 nm, 48,88 nm and particle size from SEM images were 43,06 nm, 44,91 nm dan 64,99 nm, 80,40 nm, respectively. The crystals and particle size increased with annealing temperature. The film thickness influenced material absorption. The optical measurement of TiO2 film and TiO2/phycocyanin hybrid film used UV-Vis spectrophotometer. Additional phycocyanin caused peak width of absorbed region from ultraviolet to visible region. The band gap energy of TiO2 can be calculated using the cut off wavelength obtained from the absorbance spectrum of a nanoparticles TiO2 films. Based on intersection between linear and energy (hv) axis. In this study just limited for anatase phase. It was caused anatase band gap is wider than rutile phase. That’s meaningful for solar cell application such as dye sensitized solar cell (DSSC). The absorption coefficient average at difference annealing temperature such as at 400oC, 600oC, 800oC were 8,1600x102, 1,7535x103 and 4,0154x102, where α < 104 include to direct transition. Band gap energy 400oC, 600oC, 800oC were 3,79 eV, 3,59 eV, and 3,35 eV, respectively. Based on this result, exhibition that band gap energy of TiO2 semiconductor film decreased with increasing annealing temperature. Spirulina platensis was cultivated in technical modification (Hastuti) with aeration under light intensity about 3000 lux. The cell density (stationer phase) for eighth day which OD value was more than 0,5. It means, the culture can be harvested. In 80 liters Spirulina platensis culture have been produced biomass dry about 10,46 gram and extracted phycocyanin in dry powders was 5,50 gram. The phycocyanin absorption spectrum at the wavelength of 619,36 nm (visible region) which had relaxation energy was 2,945 eV. The emission peak at the wavelength of 708,55 nm with relaxation energy about 2,793 eV. The Stokes shift based on difference energy absorption and emission calculated about 0,152 eV. Both of this showed phycocyanin can absorbed and radiated the sun light which received. This choice characteristic pigment was a good one related to sensitizer in solar cell application. Integration between light harvesting protein and TiO2 semiconductor surface had important role in improving of output as solar cell materials. The presence of carboxylate group (-COOH) made pigment be more efficient was due to anchored to the surface of TiO2 ampoter. The phycocyanin pigment had carboxylate group which reacted with TiO2 surface formed ester. The carboxylate group increased of dye electronics couple from excited state (p anti bonding orbital) to semiconductor acceptor state (TiO2 conduction band). The samples which made based on annealing temperature variation formed be solar cell respectively. Furthermore, cells be assembled for
Keyword: anatase, dye sensitized solar cell, efficiency, gap energy, phycocyanin