Judul: Kajian Overdispersi pada Regresi Poisson Berdasarkan Model Generalized Poisson
Abstrak: Generalized Poisson (GP) model is one model that can be used to overcame overdispersion in Poisson data. Detection of overdispersion in simulation data used score test, SSR-LRT test, and Wald test. Simulation data was generated based on the GP distribution. Goodness of fit of GP models in this study were analyzed by using the Root Mean Square Error (RMSE) and Akaike Information Criteria (AIC). In addition to the simulation data , this study also used applied case study data which malnutrition data in West Lombok. The results showed that the applied case study used indicated overdispersion at 5% significance level and the percentage of families living in slum area have impact on the spread of malnutrition in West Lombok. The simulation data showed that power of test of score test is more better than the other test, so that score test is consider as the most appropriate test in detecting overdispersion.
Keyword: Wald test., SSR-LRT test, score test, power of test, Generalized Poisson

Judul: Kajian Perbandingan Regresi Conway-Maxwell-Poisson dan Poisson-Tweedie dalam Mengatasi Overdispersi pada Regresi Poisson
Abstrak: Regresi Poisson adalah model yang umum digunakan untuk memodelkan data cacah. Memodelkan data cacah sering terjadi overdispersi sehingga regresi Poisson kurang tepat digunakan karena regresi Poisson mengasumsikan data equidispersi. Overdispersi dapat diatasi menggunakan regresi Conway-Maxwell-Poisson (COM-Poisson) dan Poisson Tweedie (Poisson-Tw). Model terbaik ditentukan berdasarkan RMSE, absolute bias, ragam penduga parameter, AIC, dan BIC terkecil. Penelitian ini menggunakan data simulasi dan data riil. Peubah respon pada data simulasi dibangkitkan menyebar Generalized Poisson dengan berbagai kombinasi parameter ϕ dan n. Kajian data simulasi menunjukkan bahwa regresi COM-Poisson dan Compound Poisson-Tw adalah model alternatif untuk memodelkan data cacah overdispersi, tetapi COM-Poisson lebih baik digunakan untuk tingkatan dispersi yang tinggi. Kajian data riil menunjukkan bahwa regresi COM-Poisson lebih baik digunakan dengan peubah yang berpengaruh terhadap kasus kusta di Jawa Timur tahun 2020 adalah jumlah penduduk miskin (X3) pada taraf nyata 0,05., Poisson regression is a standard method to model count data. Modeling count data frequently causes overdispersion which means that Poisson regression is less precise to model it as Poisson regression has the assumption of equidispersion. Overdispersion can be overcome by using Conway-Maxwell-Poisson (COM-Poisson) and Poisson Tweedie (Poisson-Tw) regression. The best model is determined based on the lowest value of RMSE, absolute bias, variance of parameter estimator, AIC, and BIC. This research uses both simulation and real data. The response variable of simulation data is generated to follow Generalized Poisson distribution with combinations of ϕ and n. The result of simulation study shows that COM-Poisson and Compound Poisson-Tw are the alternatives to model overdispersed count data, but COM-Poisson is better to overcome overdispersion with higher dispersion parameter level. Real data is modeled using COM-Poisson regression to analyze the number of leprosy cases in East Java 2020 and shows that the number of people living in poverty (X3) affects the number of leprosy cases in East Java 2020 at a 0,05 level of significance.
Keyword: COM-Poisson, Compound Poisson-Tw, overdispersion, Poisson

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