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: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition