Judul: Pendugaan Parameter Model Dinamik dengan Metode Robust Median Absolute Deviation (MAD)
Abstrak: Given a data set in a dynamical model with unknown parameter values, the most commonly used method for parameter estimation is the least square method. However, this method is very sensitive to outliers. Because of this, a robust method to handle outliers is used. There are several robust methods such as Least Absolute Deviation method and Median Absolute Deviation method. When the number of outliers is relatively small, the result of parameter estimation using Least Absolute Deviation method and Median Absolute Deviation method are relatively similar. However, when the number of outliers is relatively large, the Median Absolute Deviation method is the most robust method to outliers. The dynamical models used in this manuscript are logistic and SEI (Susceptible, Exposed, and Infectious) models with hypothetical data. The accuracy of parameter estimation was measured by the value of Mean Absolute Percentage Error (MAPE).
Keyword: Bogor Agricultural University (IPB), robust, outliers, Median Absolute Deviation, Least Square, Least Absolute Deviation

Judul: Pendugaan parameter model dinamik dengan metode Median Absolute Deviation (MAD) dan Huber M-Estimation
Abstrak: Parameter estimation is commonly applied to regression models. However, the estimation of the dynamic models have not been developed. Least Square Method is the most common method used in parameter estimation. However, this method is not appropriate to be used if data contains some outliers. Robust method is a method that can overcome the weakness of the Least Square method. Median Absolute Deviation and M-Estimation are some suitable methods used when the data contains outliers and far outliers. Both of these robust methods are quite good in parameter estimation for the data with or without outliers. Based on Symmetrical Mean Absolute Percentage Error (SMAPE) and boxplot, MEstimation method has better accuracy in parameter estimation than the Median Absolute Deviation method. In this manuscript, parameter estimation is applied to Gompertz and SZR (Susceptible, Zombie, Removed) model using hypothetical data.
Keyword: Bogor Agricultural University, robust, outliers, Median Absolute Deviation, Median Absolute Deviation, M-Estimation, Least Square, Huber, far outliers

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