Judul: Perbandingan Pendugaan Parameter Regresi Distribusi Normal dan Distribusi Eksponensial dengan Maximum Likelihood Estimation (MLE)
Abstrak: Analisis regresi merupakan salah satu analisis statistika yang mempelajari hubungan antara variabel dependen dan variabel independen. Variabel dependen tidak selalu berdistribusi normal, melainkan termasuk ke dalam sifat distribusi yang lebih luas yang disebut dengan distribusi dari famili eksponensial. Untuk variabel dependen yang termasuk ke dalam famili eksponensial, maka dapat dimodelkan dengan Generalized Linear Models (GLM). Metode yang dapat digunakan untuk menduga parameter pada GLM pada regresi eksponensial adalah Maximum Likelihood Estimation (MLE) dengan menggunakan konsep Iterative Re-Weighted Least Square (IRLS). Pada data yang menyebar eksponensial, jika dilakukan pendugaan parameter dengan regresi normal akan menghasilkan pendugaan parameter yang kurang baik. Oleh karena itu, data harus dimodelkan sesuai dengan asumsi sebarannya yaitu dengan menggunakan GLM., Regression analysis is a statistical analysis that studies the relationship between the dependent variable and the independent variable. The dependent variable is not always normally distributed but belongs to a wider distribution called the distribution of the exponential family. For the dependent variable that belongs to the exponential family, it can be modeled using Generalized Linear Models (GLM). The method that can be used to estimate the parameters of GLM in exponential regression is Maximum Likelihood Estimation (MLE) using the Iterative Re-Weighted Least Square (IRLS) concept. In exponentially distributed data, if the parameter estimation is carried out with normal regression, it will result in an unfavorable parameter estimate. Therefore, the data must be modeled according to the distribution assumption, namely by using GLM.
Keyword: exponential family, Generalized Linear Model (GLM), Iterative Re- Weighted Least Square (IRLS), Maximum Likelihood Estimation (MLE), regression analysis

Judul: Perbandingan Metode MKT, LTS, WIN, dan Theil pada Pendugaan Parameter Regresi Apabila Galatnya Menyebar Eksponensial
Abstrak: Parameter estimation in simple linear regression analysis can be done with Ordinary Least Square (OLS). This method requires the assumption that error must be Normally distributed. However, in reality error is not always Normally distributed, but has another distribution, for example Exponential. Concequently, parameter estimation by MKT is not optimal. This problem can be solved by applying robust regression. This research applied Least Trimmed Square (LTS) method, Winsorized Least Square (WIN) method, and Theil’s method as a solution. The data used in this study was simulation data. Explanatory variables (x) is generated from the Normal distribution, while the error generated from the Exponential distribution. The results of estimation are evaluated with MSE and Relative MSE. The results showed that LTS was the best method when the error is Exponentially distributed.
Keyword: Bogor Agricultural University (IPB), WIN, Theil’s Method, OLS, LTS

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