Judul: Penerapan Algoritma Genetik sebagai Metode Alternatif Pendugaan Parameter Regresi Logistik dan Beta-binomial
Abstrak: Logistic regression is commonly used in research to assess the relationship of proportion with one or many variables. In logistic regression, when variance of a binomial response variable is larger than it should be (overdispersion), either the model or the parameter estimation needs to be modified. An alternative that can be applied is beta-binomial regression. Parameter estimation for logistic and betabinomial regression generally done by maximizing the likelihood function through the Iteratively Reweighted Reweighted Least Square (IRLS) algorithm. However, this algorithm requires much auxiliary information to work properly such as initial domain and differential. This study is purposed to examine the application of genetic algorithm as an alternative method for estimating logistic and beta-binomial regression parameters. The result shows that genetic algorithm can generate solutions that are close to IRLS even with better log-likelihood value.
Keyword: Parameter, Logistic, Genetic Algorithm, Beta-binomial

Judul: Kajian Perbandingan Model Regresi Beta-Binomial dengan Model Regresi Logistik dan Penyerapannya untuk Menduga Pola Kelulusan Mahasiswa TPB-IPB
Abstrak: Penggunaan metode statistika yang mengasumsikan ketidakbebasan antara subunit dari gerombol (seperti dalam model regresi logistik) dapat menjadi tidak tepat. Jika terdapat korelasi antara pengamatan, maka nilai penduga parameter dari model yang tidak memperhitungkan adanya korelasi mungkin mempunyai galat baku yang underestimated. Jadi kovariat-kovariat yang ada dalam model bisa dengan keliru dianggap sebagai suatu statistik yang penting, jika keragaman yang sebenarnya di dalam data hams memberi suatu indikasi hasil yang lebih tidak jelas. Metode baku juga tidak dapat digunakan untuk memeriksa suatu permasalahan tentang korelasi diantara peubah respon. Model altematif yang diusulkan sesuai dengan permasalahan yang diamati adalah model regresi beta-binomial. Pemilihan model beta-binomial ini didasarkan pada kemudahan-kemudahannya, baik dalam perhitungan penurunan hngsi kemungkinannya maupun dalam menginterpretasi parameter-parameter yang berada di dalam model.
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Judul: Elektrodeposisi Film Tipis Semikonduktor Cu2ZnSnS4 (CZTS) pada Substrat Kaca ITO
Abstrak: Semiconductor Cu2ZnSnS4 (CZTS) thin film that can be used as absorber layers on solar cell module was made via electrodeposition method. CZTS thin film was electrodeposited on the surface of a silicate glass coated with a thin layer of indium tin oxide (ITO). Deposition process was done using potentiostatic mode at room temperature with a potential of 1.05 V for 30, 45, and 60 minutes, followed with annealing the film at 2 different temperatures, 500 ºC using furnace and 180 ºC using hot plate, both treatments for 45 minutes in N2/H2S atmosphere. The X-ray difractograms were analyzed using Match 2 program and showed that the CZTS thin films had kesterit crystalline structure, with a low percentage of CZTS phase. The thin film also contained secondary phases such as Cu2S, ZnS, and SnS. The obtained CZTS thin films had a thickness between 1.039 and 1.676 μm. Absorption study showed that the band gap energy of CZTS thin films which was annealed using furnace ranged from 1.50 to 1.52 eV, whereas that annealed using the hot plate was not observed. The band gap energy value showed that CZTS thin films can be used as sunlight absorber layers on solar cell. The formation of CZTS crystal film on this investigation was effectively performed using furnace annealing process at a temperature of 500 ºC with deposition time of 45 minutes.
Keyword: Thin film, Electrodeposition, Cu2ZnSnS4