Judul: Analisis dan Prediksi Pertumbuhan Jumlah Kasus COVID-19 di Pulau Jawa Menggunakan Metode Linear Regression dengan ARIMA Error
Abstrak: Coronavirus Disease 2019 (COVID-19) merupakan penyakit menular yang menyebabkan gangguan pada pernapasan dan radang paru-paru. COVID-19 ditetapkan sebagai pandemi pada 11 Maret 2020. Pulau Jawa merupakan pulau yang memiliki kasus terkonfirmasi positif COVID-19 terbanyak di Indonesia. Jumlah kasus terkonfirmasi positif COVID-19 di Pulau Jawa dapat disebabkan oleh beberapa faktor, salah satunya adalah mobilitas masyarakat. Penelitian ini melakukan analisis terkait dampak kebijakan yang diterapkan oleh pemerintah dalam menekan mobilitas masyarakat, yaitu Kebijakan Pemberlakuan Pembatasan Kegiatan Masyarakat (PPKM). Selain itu, fokus utama pada penelitian ini adalah melakukan analisis prediktif jumlah kasus terkonfirmasi positif COVID-19 menggunakan Linear Regression dengan ARIMA error. Dengan menggunakan Linear Regression dengan ARIMA error dan prediktor berupa data mobilitas didapatkan nilai MAPE pada model yang buat berkisar antara 10,90% hingga 22,93% tiap provinsinya kecuali Jawa Tengah yang memiliki nilai MAPE sebesar 47,02%., Coronavirus Disease 2019 (COVID-19) is an infectious disease that causes respiratory problems and inflammation of the lungs. COVID-19 was declared a pandemic on March 11, 2020. The island of Java is the island that has the most positive confirmed cases of COVID-19 in Indonesia. The number of positive confirmed cases of COVID-19 in Java can be caused by several factors, one of which is community mobility. This study analyzes the impact of policies implemented by the government in suppressing community mobility, namely the Policy for the Enforcement of Restrictions on Community Activities (PPKM). In addition, the main focus of this study is to carry out a predictive analysis of the number of positive confirmed cases of COVID-19 using Linear Regression with ARIMA error. By using linear regression with ARIMA error and employing the mobility predictors, we obtained a MAPE value within the range of 10,90% to 22,93% for each province, with the exception of Jawa Tengah which had a MAPE of 47,02%.
Keyword: ARIMA error, COVID-19, linear regression, PPKM

Judul: Description and Prediction Analysis of the Spread of COVID-19 Cases in East Java Province
Abstrak: Coronavirus Disease 2019 (COVID-19) merupakan penyakit menular yang dapat menyebabkan gangguan sistem pernapasan. Penyakit ini memiliki sifat yang mudah menular antar individu. Laju penyebaran COVID-19 dapat dipengaruhi oleh keadaan sosial-ekonomi suatu wilayah. Penelitian ini akan menggunakan model Autoregressive Integrated Moving Average (ARIMA) untuk memprediksi jumlah kasus COVID-19 di Provinsi Jawa Timur. Model ARIMA (1,1,1) yang diperoleh mampu memprediksi jumlah kasus penyebaran COVID-19 dengan baik ditunjukkan dengan nilai Mean Absolute Percentage Error (MAPE) sebesar 12,70%. Nilai tersebut menunjukan bahwa kesalahan peramalan berkisar 12,70% saja dari nilai aktual di lapangan. Model yang diperoleh baik untuk memprediksi dalam jangka pendek harian. Selain itu, dilakukan analisis pengaruh faktor sosial-ekonomi terhadap laju transmisi COVID-19 di Provinsi Jawa Timur. Faktor yang paling berpengaruh terhadap banyaknya jumlah kasus COVID-19 di Provinsi Jawa Timur adalah Produk Domestik Regional Bruto-Atas Dasar Harga Konstan (PDRB-ADHK), Persentase Penduduk Lansia, dan Jumlah Populasi.
Keyword: COVID-19, deskripsi, ekonomi, prediksi, sosial

Judul: Hybrid solar cells of ZnO nanoparticles/chlorophyll was modified metal ions (Zn2+ and Cu2+ )
Abstrak: Zinc Oxide (ZnO) is a n-type semiconductor with a wide the energy band (Band Gap) is 3.37 eV at room temperature and 3.34 eV at low temperature with a large exiton binding energy is 60 meV. ZnO has been synthesized by hydrothermal method, resulting in a decrease in particle size over the duration of the hydrothermal changes. Crystallographic structure of ZnO were characterized using XRD, has shown the characteristic pattern of a hexagonal wurtzite structure, the crystallite size increases to changes in particle size. Changes in particle size has also led to a change in the absorption peak of ZnO as has been demonstrated posted under test using the optical properties of UV-Vis spectrophotometer. Changes of this uptake has also led to changes in the energy band gap, which increases its band gap energy of the particle size. In electronic applications, especially in solar cells. Chlorophyll is considered less effective, because of their very nature are easily degraded as a result of several reactions which are acid, lighting and temperature. The results of the stability test using a halogen lamp 34 W/m2 for 5 hours, that the substitution of chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form more stable than natural chlorophyll. The characterization of the optical properties, the combination of ZnO / chlorophyll in the form of hybrid films has led to a shift in the absorption region of ZnO becomes more widely from the UV to Visible. ZnO/chlorophyll has absorption range of 350-515 nm, ZnO / Zn-feofitin 332-401 nm and 332-632 nm for Cu-feofitin. The combination of ZnO/chlorophyll and CuSCN as a solid electrolite in hybrid solar cell, a modified chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form a more stable I-V curve. It is characterized by its fill factor value greater than natural chlorophyll. Nevertheless, solar cells with natural chlorophyll has been able to produce higher efficiency values of chlorophyll were substituted.
Keyword: Hydrothermal, ZnO/Chlorophyll modified, Hybrid Solar Cell