Judul: Analisis Minat Beli Konsumen pada Produk Daging Olahan dengan Sistem Keterlacakan QR (Quick Response) Code di Masa Pandemi COVID-19
Abstrak: Sejak terjadinya pandemi COVID-19, masyarakat menjadi lebih selektif terhadap bahan pangan yang dikonsumsi dan industri pengolahan daging dalam negeri mengalami penurunan permintaan. Salah satu solusi untuk produk daging olahan yang aman serta berkualitas adalah sistem keterlacakan QR Code. Penelitian ini bertujuan untuk menganalisis minat beli konsumen terhadap produk daging olahan dengan sistem keterlacakan QR Code semasa pandemi COVID-19 di Jakarta melalui integrasi model berdasarkan pendekatan Theory of Planned Behaviour (TPB), Technology Acceptance Model (TAM), variabel health consciousness, media exposure, serta habits. Responden yang diperoleh sebanyak 230 orang. Data yang digunakan dalam penelitian ini merupakan data primer dan data sekunder. Penelitian ini menggunakan metode analisis deskriptif dan SEM-PLS. Hasil dari penelitian ini adalah subjective norms dan attitude memengaruhi purchase intention secara langsung. Media exposure memengaruhi purchase intention melalui health consciousness, perceived information, dan attitude. Perceived information memengaruhi purchase intention melalui perceived usefulness. Perceived usefulness memengaruhi purchase intention melalui attitude. Perceived Ease of Use memengaruhi purchase intention melalui perceived usefulness dan attitude. Health Consciousness dan Habits tidak berpengaruh langsung dengan purchase intention, tetapi health consciousness berpengaruh baik dengan habits, habits berpengaruh baik dengan attitude yang berpengaruh baik dengan purchase intention., Since the COVID-19 pandemic, people become selective on food and the domestic meat processing industry has experienced a decline in demand. One of the solutions for safe processed meat products is the QR Code traceability system. This study aims to analyse consumer’s purchase intention towards traceable processed meat products with QR Code during the COVID-19 pandemic in Jakarta through model integration based on the approach of Theory of Planned Behavior (TPB), Technology Acceptance Model (TAM) and variables including health consciousness, media exposure, as well as habits. Total respondents obtained were 230 people. This research uses descriptive analysis method and SEM-PLS with primary data and secondary data. The results show that subjective norms and attitudes directly affect purchase intention. Media exposure affects purchase intention through health consciousness, perceived information, and attitude. Perceived information affects purchase intention through perceived usefulness. Perceived usefulness affects purchase intention through attitude. perceived ease of use affects purchase intention through perceived usefulness and attitude. health consciousness and habits do not have a direct effect on purchase intention, but health consciousness has a good effect on habits, habits have a good effect on attitude which has a good effect on purchase intention.
Keyword: COVID-19, Processed Meat Products, Purchase Intention, QR Code, Traceability System

Judul: Identification of Changes in Food Consumer Behavior during the Covid-19 Pandemic in Jabodetabek
Abstrak: Adanya pandemi Covid-19, kemungkinan dapat mengakibatkan perubahan pola perilaku konsumen pangan. Penelitian ini bertujuan untuk mengetahui produk pangan yang dibeli selama pandemi Covid-19, mengidentifikasi cara pembelian produk pangan dan tempat pembeliannya, mengidentifikasi faktor yang memengaruhi konsumen dalam membeli produk pangan, serta membandingkan perilaku konsumen sebelum dan selama pandemi Covid-19 di wilayah Jabodetabek. Metode yang digunakan yaitu survei online dengan teknik purposive sampling. Data dianalisis menggunakan analisis deskriptif dan analisis korelasi. Hasil survei menunjukkan bahwa terdapat produk yang mengalami peningkatan pembelian yaitu sayur dan buah segar, telur, mi instan, air mineral, minuman herbal, serta jus buah. Produk yang mengalami penurunan pembelian yaitu minuman karbonasi, minuman energi, sirup, makanan siap saji, serta makanan kaleng. Produk yang tidak mengalami perubahan pembelian diantaranya beras, daging segar maupun olahan, ikan dan seafood, roti, biskuit dan kue kering, susu dan olahannya, makanan ringan, makanan beku, sereal sarapan, bumbu masakan instan, teh siap minum, minuman isotonik, serta konfeksioneri. Terjadi pula peningkatan cara pembelian melalui online store selama pandemi Covid-19. Hasil uji Chi-Square menunjukkan terdapat 13 faktor yang memengaruhi pembelian beberapa produk pangan selama pandemi Covid-19 diantaranya yaitu domisili, jenis kelamin, usia, pendidikan, pekerjaan, merek, sensori, manfaat, kemudahan diperoleh, kandungan gizi, keamanan pangan, harga, serta ketersediaan., The existence of Covid-19 pandemic is thought to have resulted in changes in food consumer behavior patterns. This study aims to determine the food products purchased during Covid-19 pandemic, identify how to purchase food products and where to buy them, identify factors that influence consumers to buy food products, and compare consumer behavior before and during the Covid-19 pandemic in Jabodetabek. The method used is an online survey with purposive sampling technique. Data were analyzed using descriptive analysis and correlation analysis. The survey results showed that there were products that experienced an increase in purchases, such as fresh vegetables and fruit, eggs, instant noodles, mineral water, herbal drinks, and fruit juices. Products that experienced a decline in purchases were carbonated drinks, energy drinks, syrups, ready-to-eat food and canned food. Products that are regularly purchased include rice, fresh and processed meat, fish and seafood, bread, biscuits and pastries, milk and processed foods, snacks, frozen foods, breakfast cereals, instant cooking spices, ready-to-drink tea, isotonic drinks, and confectionery. There has also been an increase in ways of purchasing via online stores during the Covid-19 pandemic. The results of Chi-Square test showed that there were 13 factors that influenced the purchase of several food products during the Covid-19 pandemic including domicile, gender, age, education, occupation, brand, sensory, benefits, accessibility, nutritional content, food safety, price, and product availability.
Keyword: Covid-19, Perilaku konsumen, Survei online, consumer behavior, covid-19, online survey

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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