Judul: Analysis of Cold Vegetables Market Opportunities Based on Purchase Intention and Consumer Preferences in the Covid- 19 Pandemic
Abstrak: Sulitnya distribusi pangan seperti sayuran pada masa pandemi Covid-19 membuat permintaan dan pasokan pangan sayuran tidak seimbang yang berujung pada terbuangnya sayuran, sehingga perlu penanganan yang tepat pada sayuran karena bersifat mudah rusak dengan cold chain system. Tetapi ada biaya tambahan bagi konsumen karena penerapan cold chain system perlu biaya yang tinggi. Penelitian ini dilakukan untuk mengukur permintaan konsumen pada sayuran berpendingin agar diketahui peluang pasarnya pada masa pandemi Covid-19. Penelitian ini bertujuan mengidentifikasi karakteristik konsumen sayuran berpendingin; menganalisis pengaruh persepsi, sikap, dan preferensi terhadap minat beli sayuran berpendingin; dan menganalisis preferensi konsumen pada sayuran berpendingin. Sampel penelitian ini sebanyak 385 orang yang tersebar di Provinsi DKI Jakarta dengan metode penentuan sampelnya yaitu non-probability sampling jenis convenience sampling. Diolah dengan analisis Structural Equation Modeling-Partial Least Square (SEM-PLS) dan analisis konjoin. Hasil penelitian ini akan menjadi rekomendasi bagi para akademisi, pelaku usaha, petani, dan pemerintah agar tercipta sinergi strategis, sehingga tujuan dan manfaat penelitian dapat dicapai. Kata kunci: minat beli, preferensi, sayuran berpendingin, SEM-PLS, The difficulty of food distribution such as vegetables during the Covid-19 pandemic made the demand and supply of vegetable unbalanced. So, it needs proper handling of vegetables because it is perishable by the cold chain system. However, there are additional costs for consumers because a cold chain system requires high costs. This research was conducted to measure consumer demand for cold vegetable products in order to know the market opportunities during the Covid-19 pandemic. This research aims to identify the characteristics of cold vegetable consumers; analyzing the influence of perceptions, attitudes, and preferences on purchase intention in cold vegetables; and analyzing consumer preferences for cold vegetables. The sample of this research was 385 people who were spread in DKI Jakarta Province with the method of determining the sample is non-probability sampling type convenience sampling. This research uses Structural Equation Modeling-Partial Least Square (SEM-PLS) analysis and conjoint analysis. The results of this research will be a recommendation for academics, business actors, farmers, and the government to create strategic synergies, so that the objectives and benefits of this research can be achieved. Keywords: cold vegetables, preference, purchase intention, SEM-PLS
Keyword: minat beli, preferensi, sayuran berpendingin, SEM-PLS, cold vegetables, preference, purchase intention

Judul: The Effect of New Normal Situation on Intention and Behavior to Purchase Vegetables Through Agricultural E-commerce
Abstrak: Tren peningkatan penetrasi internet di Indonesia dimanfaatkan masyarakat untuk melakukan transaksi bisnis secara daring melalui e-commerce pertanian. Situasi new normal di Indonesia tetap menjadi faktor penting keputusan pembelian sayuran secara online. E-commerce pertanian digunakan masyarakat untuk memenuhi kebutuhan sehari-hari dalam membeli produk sayuran. Penelitian ini bertujuan untuk menganalisis sikap, norma subjektif, kontrol perilaku, dan situasi new normal terhadap niat dan perilaku pembelian sayuran melalui e-commerce pertanian. Penelitian ini menggunakan data primer melalui penyebaran kuesioner secara daring dengan jumlah 130 responden. Metode yang digunakan dalam penelitian ini adalah analisis deskriptif dan Structural Equation Model-Partial Least Square (SEM-PLS). Hasil penelitian ini menunjukkan bahwa konsumen sayuran e-commerce pertanian adalah perempuan muda yang mandiri dan menyukai belanja sayuran di Sayurbox, HappyFresh, Segari, TukangSayur.id, dan Astro. Variabel sikap dan situasi berpengaruh signifikan terhadap niat pembelian sayuran dan kontrol perilaku berpengaruh signifikan secara langsung terhadap perilaku pembelian sayuran melalui e-commerce pertanian., An increasing trend of increasing internet penetration which is used by the public to conduct business transaction through agricultural e-commerce. New normal situation in Indonesia remains an important factor in online purchasing decisions for vegetables. Agricultural e-commerce is used by the community to provide their daily needs in buying vegetable products. This study aims to analyze planned behavior attitudes, subjective norms, behavioral control, and situation on vegetable purchase intentions and behavior through agricultural e-commerce. This study uses primary data through online questionnaires with a total of 130 respondents. The method used in this research is descriptive analysis and Structural Equation Model-Partial Least Square (SEM-PLS). The results of this study indicate that consumers of vegetables through agricultural e-commerce is an independent young woman who loves shopping for vegetables at Sayurbox, HappyFresh, Segari, TukangSayur.id, and Astro. Attitude and situation variables have a significant effect on the intention to buy vegetables and behavioral control has a significant direct effect on the decision to buy vegetables through agricultural e-commerce.
Keyword: e-commerce, perilaku pembelian, 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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