Judul: Analisis Sikap Konsumen Pada Masa Pandemi Covid-19 dan Pengaruhnya Terhadap Keputusan Pembelian di Coffee Shop Jabodetabek
Abstrak: Pandemi Covid-19 berdampak negatif pada berbagai macam jenis usaha secara langsung termasuk coffee shop yang merupakan tempat orang melakukan interaksi dan berkumpul. Tujuan penelitian adalah untuk menganalisis pengaruh sikap konsumen pada pandemi Covid-19 terhadap keputusan pembelian di coffee shop. Sampel dari penelitian ini adalah masyarakat di Jabodetabek sebanyak 100 orang menggunakan metode non-probability sampling dan teknik purposive sampling. Pengambilan data sampel dilakukan dengan menyebarkan kuesioner ke konsumen yang pernah melakukan kunjungan coffee shop di Jabodetabek . Analisis dilakukan dengan metode Structural Equation Modelling (SEM). Hasil analisis menunjukkan konsumen mengetahui dan meyakini pandemi Covid-19 dan protokol kesehatan. Konsumen juga menerapkan protokol kesehatan Covid-19 dari pemerintah. Sikap konsumen pada masa pandemi ini berpengaruh negatif terhadap keputusan pembelian di coffee shop Jabodetabek
Keyword: Attitudes, Coffee Shop, Covid-19 Pandemic, Purchase Decision, SEM

Judul: The effect of implementation Covid-19 protocol on  purchase intention and purchase decision in the Starbucks area of Bogor City
Abstrak: Indonesia menjadi salah satu negara yang terdampak pandemi Covid-19. Pada pandemi ini terdeteksi 3.194.733 kasus positif, 560.278 kasus aktif, 2.549.692 sembuh, dan 84.766 wafat di Indonesia. Dampak dari Covid-19 merubah keadaan kehidupan normal dan menciptakan ‘new normal”, dengan menerapkan 3M: menggunakan masker, membersihkan tangan dengan menggunakan sabun, dan menjaga jarak. Karena hal tesebut, Starbucks harus beradaptasi dalam fase new normal untuk meningkatkan kembali penjualan. Tujuan penelitian Mengidentifikasi karakteristik konsumen di Starbucks area Kota Bogor, Menganalisis pengaruh protokol Covid-19 terhadap purchase intention dan purchase decison di Starbucks area Kota Bogor. Pada penelitian ini digunakan teknik sampling non-probability, yaitu teknik convinience sampling dan dengan teknik analisis data SEM-PLS (Structural Equation Modeling-Partial Least Square) dengan jumlah 100 responden yang memiliki karakteristik yang pernah membeli produk Starbucks. Hasil dari penelitian ini menyatakan bahwa variabel protokol covid-19 tidak memiliki pengaruh terhadap purchase intention, tetapi protokol covid-19 dan purchase intention berpengaruh signifikan terhadap purchase decision., Indonesia is one of the countries affected by the Covid-19 pandemic. During this pandemic, 3,194,733 positive cases were detected, 560,278 active cases, 2,549,692 recovered, and 84,766 died in Indonesia. The impact of Covid-19 changes normal living conditions and creates a 'new normal', by implementing 3M: using masks, cleaning hands with soap, and maintaining distance. Because of this, Starbucks had to adapt to the new normal phase to increase sales returns. The objectives of this study are: To identify the characteristics of consumers at Starbucks in the Bogor City area, to analyze the effect of the Covid-19 protocol on purchase intention and purchase decisions at Starbucks in the Bogor City area. In this study, non-probability sampling techniques were used, namely the convenience sampling technique and the SEM-PLS (Structural Equation Modeling Partial Least Square) data analysis technique with a total of 100 respondents who had characteristics who had bought Starbucks products. The results of this study stated that the variables of the covid-19 protocol had no effect on the purchase intention, while the covid-19 protocol and purchase intention had a significant effect on the purchase decision.
Keyword: Covid-19 protocol, Purchase intention, Purchase decision, Starbucks, SEM-PLS

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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