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: Impact of Consumer Knowledge and Perception towards Purchase Intention of Frozen Fish Products in Cold Chain System
Abstrak: Pandemi Covid-19 mengakibatkan kegiatan usaha perikanan mengalami gangguan terutama terkait dengan mobilitas pengiriman . Sistem cold chain dapat membantu distribusi ikan selama pandemi. Ikan beku dari sistem cold chain dapat menjadi alternatif makanan yang dikonsumsi masyarakat untuk meningkatkan imunitas selama pandemi. Oleh karena itu penelitian ini bertujuan untuk menganalisis profil konsumen ikan beku dan karakteristik pembeliannya, serta menganalisis pengaruh pengetahuan, persepsi, sikap dan norma subjektif konsumen terhadap minat membeli ikan beku pada masa pandemi. Sampel pada penelitian ini sebanyak 247 responden yang tersebar di Kota Bekasi, Jawa Barat. Teknik penentuan sampel menggunakan non-probability sampling jenis convenience sampling. Analisis data menggunakan SEM-PLS dan analisis crosstab. Hasil menunjukkan responden yang bependidikan tinggi akan cenderung memilih untuk membeli ikan beku daripada yang tidak berpendidikan tinggi. Hasil penelitian juga menunjukkan bahwa pengetahuan, persepsi, sikap, dan norma subjektif berpengaruh positif dan signifikan terhadap minat beli., The Covid-19 pandemic has resulted in disruption of business activities, especially those related to shipping transfers. Cold chain systems can help with fish distribution during a pandemic. Frozen fish from the cold chain system can be an alternative food consumed by the community to increase immunity during a pandemic. Therefore, this study aims to analyze the profile of frozen fish consumers and their purchasing characteristics, as well as to analyze the influence of consumer knowledge, perceptions, attitudes and subjective norms on the interest in buying frozen fish during the pandemic. The sample in this study were 247 respondents spread across the city of Bekasi, West Java. The sampling technique used was non-probability sampling, which was convenience sampling. Data analysis using SEM-PLS and crosstab analysis. The results show that respondents with higher education will choose to buy frozen fish than those who are not highly educated. The results also show that knowledge, perceptions, attitudes, and subjective norms have a positive and significant effect on buying interest.
Keyword: cold chain, crosstab, frozen fish, purchase intention, 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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