Judul: Application of Poisson Regression and Negative Binomial Regression on Toddler Diarrhea Cases in West Java
Abstrak: Indonesia menempati posisi ketujuh dengan jumlah kematian balita tertinggi di dunia. Diare merupakan pembunuh utama anak balita di seluruh dunia pada tahun 2019. Diare menjadi penyebab utama kematian terbanyak pada balita (12-59 bulan) di Indonesia, sebesar 10,3%. Provinsi Jawa Barat merupakan provinsi dengan jumlah temuan kasus diare balita tertinggi. Penyakit diare merupakan penyakit endemis di Jawa Barat, serta berpotensi Kejadian Luar Biasa (KLB) yang sering disertai kematian. Oleh karena itu, penelitian ini bertujuan untuk menganalisis faktor-faktor yang memengaruhi jumlah kejadian diare balita di Jawa Barat. Kajian ini menggunakan data sekunder yang diperoleh dari BPS dan Dinas Kesehatan Jawa Barat. Data kejadian diare balita merupakan data cacah sehingga metode yang digunakan dalam penelitian ini adalah regresi Poisson dan regresi binomial negatif. Hasil penelitian ini menunjukkan bahwa model regresi binomial negatif lebih baik dari regresi Poisson dalam memodelkan data cacah yang mengalami overdispersi. Nilai AIC dari model regresi binomial negatif adalah 436,4. Peubah yang memengaruhi jumlah kasus diare balita di Jawa Barat adalah persentase tempat-tempat umum (TTU) yang memenuhi syarat kesehatan, persentase sanitasi total berbasis masyarakat, persentase penduduk miskin, kepadatan penduduk per km2, dan persentase rumah tangga berperilaku hidup bersih dan sehat (ber-PHBS)., Indonesia ranked seventh with the highest number of under-five child deaths globally. Diarrhea is the main killer of children under-five worldwide in 2019. Diarrhea is the most common cause of death among toddlers (12-59 months) in Indonesia, amounting to 10.3%. West Java Province is the province with the highest number of cases of diarrhea under-five. Diarrheal disease is an endemic disease in West Java and has the potential for Extraordinary Events (KLB), often accompanied by death. Therefore, this study aims to analyze the factors influencing under-five diarrhea incidence in West Java. This study used secondary data from BPS and the West Java Health Office. The data of cases of diarrhea under-five is count data, so the method used in this research was Poisson regression and binomial negative regression. The results of this study showed that negative binomial regression is better than Poisson regression in modelling count data with overdispersion. The AIC value of negative binomial regression model was 436.4. The variables that influence the number of cases of diarrhea under-five were the percentage of public places that hygiene, the percentage of community-based total sanitation, the percentage of poor people, the population density per km2, and the percentage of people with a clean and healthy lifestyle.
Keyword: balita, diare, overdispersi, regresi binomial negatif, regresi poisson

Judul: Comparison Between Poisson, Quasi-Poisson, and Binomial Negative Regression in Analyzing Under-Five Children Malnutrition Cases in East Java
Abstrak: Model regresi paling sederhana dalam memodelkan data dengan peubah respon berupa data cacahan adalah regresi Poisson. Masalah yang sering dijumpai saat menggunakan regresi Poisson adalah masalah overdispersi. Alternatif pemodelan lain yang dapat digunakan pada data dengan kondisi overdispersi adalah regresi quasi-Poisson dan binomial negatif. Pada penelitian ini, akan ditentukan model regresi terbaik yang sesuai dalam memodelkan jumlah kasus gizi buruk balita di Jawa Timur yang merupakan data cacahan dengan kondisi overdispersi. Data diperoleh dari Buku Profil Kesehatan Jawa Timur tahun 2018. Perbandingan model antara regresi Poisson, quasi-Poisson, dan binomial negatif dilakukan dengan melihat plot perbandingan hasil prediksi, plot estimasi rataan dan ragam, serta plot perbandingan pemberian bobot pada algoritma IWLS. Hasil perbandingan menunjukkan bahwa regresi quasi-Poisson merupakan model yang lebih sesuai dalam memodelkan jumlah kasus gizi buruk balita di Jawa Timur. Hasil pengujian pada taraf nyata 10% membuktikan bahwa persentase balita yang menerima ASI eksklusif, persentase balita yang menerima pelayanan kesehatan minimal 8 kali, dan persentase penduduk dengan akses terhadap sanitasi layak merupakan faktor-faktor yang berpengaruh nyata dan signifikan terhadap jumlah kasus gizi buruk balita di Jawa Timur. Penggerombolan dilakukan pada 37 kabupaten/kota di Jawa Timur berdasarkan ketiga faktor tersebut. Kabupaten/kota digerombolkan menjadi tiga zona dengan karakteristiknya masing-masing., The most straightforward counted data regression is Poisson regression. The problem often discovered in Poisson regression is overdispersion. Some alternatives regression that can be used in an overdispersed counted data are quasi-Poisson and binomial negative regression. This study will identify the most appropriate and suitable regression in modelling the number of under-five children malnutrition cases in East Java as an overdispersed counted data. The data was obtained from 2018th East Java Health Profile Book. Comparison between Poisson, quasi-Poisson, and negative binomial regression will be made based on a prediction plot, a mean-variance plot, and a comparison plot of observation weight in IWLS algorithm. The comparison shows that quasi-Poisson regression is more suitable for modelling the number of under-five children malnutrition cases in East Java. Hypothesis testing result in 10% significance level shows that the percentage of under-five children who receive exclusive breastfeeding, the percentage of under-five children who receive health services at least 8 times, and the percentage of population with proper sanitation access are factors that significantly affect the number of under-five children malnutrition cases in East Java. Based on the three significant factors, 37 regions in East Java later clustered into three clusters with their characteristics.
Keyword: binomial negative regression, overdispersion, Poisson regression, quasi-Poisson regression, under-five children malnutrition

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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