Judul: Keputusan Pembelian Produk Makanan Berlabel Halal pada Layanan Delivery Online Selama Pandemi COVID-19 di Kota Bogor
Abstrak: Salah satu jasa yang berkembang selama pandemi adalah layanan delivery online untuk makanan. Namun, tidak semua makanan yang tersedia pada layanan delivery memiliki logo halal. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi keputusan pembelian produk makanan berlabel halal pada layanan delivery online selama pandemi COVID-19 di Kota Bogor. Responden pada penelitian ini berjumlah 100 orang mewakili masyarakat Muslim Kota Bogor dan pengambilan data menggunakan kuesioner dengan skala likert. Analisis data menggunakan statistik deskriptif menunjukkan karakteristik masyarakat Muslim pada penelitian ini didominasi oleh responden dengan usia 18 – 24 tahun dengan 70 persen responden sudah memiliki pendapatan sendiri. Hasil regresi logistik menunujukkan variabel layanan penjual produk makanan, promosi, dan faktor sosial memiliki peluang yang signifikan terhadap keputusan pembelian produk makanan berlabel halal selama pandemi., One of the emerging services during the pandemic is food delivery online services. However, not all food available within the delivery service has halal logo. This research aims to determine the factors that influence the decision to purchase food products on delivery online services during the COVID-19 pandemic in Bogor. The sample of this study are 100 respondents representing Muslim Community in Bogor and the data is collected using questionnaire with Likert scale. The data was analyzed using descriptive statistics, showing that the characteristics of Muslim Community within this research are dominated by respondents aged 18-24 years old, with 70 of the respondents already having their own income. The results of logistic regression show that the variables of food product seller service, promotion, and social factors have significant opportunity towards the purchase decision for halal-labeled products during the pandemic.
Keyword: Halal Food Products, Delivery Online, COVID-19, Regresi Logistik

Judul: Keputusan Pembelian Kosmetik Halal Oleh Muslimah Kota Bogor Selama Pandemi COVID-19
Abstrak: Indonesia sebagai negara mayoritas muslim terbesar di dunia merupakan pasar potensial bagi produk halal termasuk kosmetik. Namun, akibat pandemi COVID-19 kinerja industri kosmetik di Indonesia mengalami penurunan termasuk kosmetik halal. Penelitian ini bertujuan untuk mengetahui keputusan pembelian kosmetik halal oleh muslimah Kota Bogor selama masa pandemi. Sampel penelitian ini berjumlah 100 responden mewakili muslimah Kota Bogor dan pengambilan data menggunakan kuesioner dengan skala likert. Analisis data menggunakan statistik deskriptif dan regresi logistik. Berdasarkan hasil analisis statistik deskriptif karakteristik muslimah pada penelitian ini didominasi dengan usia 15 tahun hingga 25 tahun dan membeli kosmetik halal selama pandemi didominasi oleh responden pada usia 15 tahun – 25 tahun. Berdasarkan hasil analisis regresi logistik variabel promosi, tren dan halal awareness memiliki peluang yang signifikan terhadap keputusan pembelian kosmetik halal selama masa pandemi., Indonesia as the largest Muslim country in the world is a potential market for halal products, including cosmetics. However, due to the COVID-19 pandemic, the performance of the cosmetic industry in Indonesia has decreased, including halal cosmetics. This study aims to determine the decision to purchase halal cosmetics by Muslim women in Bogor City during the pandemic. The sample of this study amounted to 100 respondents representing Muslim women in the city of Bogor and data collection using a questionnaire with a Likert scale. Data analysis used descriptive statistics and logistic regression. Based on statistical analysis of the characteristics of Muslim women in this study, they were dominated by the age of 15 years to 25 years and halal cosmetics during the pandemic were dominated by respondents at the age of 15 years to 25 years. Based on the results of the logistic regression analysis of promotion variables, trends and awareness of halal have a significant opportunity to purchase halal cosmetics during the pandemic.
Keyword: Halal Awareness, Logistic Regression, Promotion, Purchase Decision, Trend

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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