Judul: Perbandingan Kinerja Pembobotan Ciri pada Temu Kembali Citra Menggunakan Bayesian Network dan Algoritme Genetika
Abstrak: This research proposes performance comparison on image retrieval using bayesian network and genetic algorithm, which combines color, shape and texture information. Histogram-162 is used for color feature, edge direction histogram for shape feature and co-occurrence matrix for texture feature. Combining multiple features in image retrieval process can be implemented using feature weight assignment. Bayesian network and genetic algorithm is used to find the optimal weight. This research used 1050 images with various classes i.e car, lion, sunset, texture, bear, elephant, arrow, landscape, reptile and aircraft. Experiment results shows that genetic algorithm has better precision than bayesian network on recall between 0.0 and 0.3.
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Judul: Relevance Feedback pada Temu Kembali Citra Menggunakan Bayesian Network
Abstrak: Query results not always match with user's desire. The key issue in relevance feedback is how to utilize the feedback information to improve the retrieval performance. This research proposed a method of relevance feedback using the Bayesian network model. Research data consists of 550 images which are grouped into 11 classes. The information concern in this model are histogram-l 62 for color infonnation, gradient for shape information and co-occurrence matrix for texture infOlmation. This research used Rocchio as relevance feedback algorithm. Re-weighting in feature vector used inter-weight and intra-weight updating theory. The weights that have been updated then it was used as posterior probability, and also used as a rank ofrelevant image. Evaluation of retrieval result is computed using average value of precision, the results showed that average value of precision for all classes is increasing about 4.7959% on Bayesian network model with relevance feedback compared with Bayesian network model without relevance feedback. Through the results, this research can improve the retrieval perfonnance in CBIR.
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Judul: Karakteristik Piezoelektrik Film LaxSr₁-xTiO3 di atas Substrat TCO
Abstrak: Studi material perovskite SrTiO3 sudah banyak dilakukan dan menunjukkan sifat feroelektrik, piezoelektrik, kuantum paraelektrik dan superkonduktor yang baik. Dengan penambahan dopant La2O3 diduga menambah performa sifat piezo dan karakteristik lainnya. Karakteristik film LaxSr₁-xTiO3 (LST) dengan variasi x= 0, 0.02, 0.04, 0.06 terbentuk pada suhu annealing 550 oC di atas substrat TCO melalui metode (Chemical Solution Deposition) CSD dan spin coating dengan 700 rpm pada kondisi suhu ruang dan tekanan atmosfer standar. Hasil menunjukkan, semakin banyak pendadah La maka nilai ketebalan film, ukuran rerata kristalit, parameter kisi, transmitansi, nilai konduktivitas (maksimum 589.7 S/cm pada sampel x=0.04 di frekuensi 10 Hz), nilai konstanta tegangan (c) dan muatan (d) piezo semakin meningkat. Dinamika bentuk grafik nilai tegangan (V) dan konstanta regangan mekanik (s) nampak mirip. Nilai V mencapai 0.127 V untuk x=0.06 (beban 50 g). Nilai maksimum c, d, s masing-masing mencapai 20.07 Vm/N, 1.14x10-8 C/N, 13642.71. Nilai band gap untuk x=0, 0.02, 0.04, 0.06 masing-masing 3.21 eV, 3.1 eV, 2.6 eV, 2.4 eV. La2O3 menambah performa sifat piezo, sehingga LST berpotensi sebagai sensor tekanan.
Keyword: CSD method, La2O3, LaxSr1-xTiO3, piezoelectric, TCO