Judul: The Effectiveness of Instagram as a Promotion Media for Processed Agricultural
Abstrak: Usaha Mikro Kecil Menengah (UMKM) bidang kuliner merupakan kegiatan agroindustri yang memiliki peran penting dalam perekonomian nasional. Para pelaku UMKM saat pandemi Covid-19 dapat memanfaatkan media digital dalam upaya memasarkan produknya agar konsumen semakin mengenal produk yang dihasilkan UMKM tersebut. Tujuan penelitian adalah menganalisis efektivitas instagram sebagai media promosi produk Es Teh Indonesia, menganalisis hubungan karakteristik konsumen dan keterdedahan media sosial dengan efektivitas media promosi produk olahan pertanian Es Teh Indonesia. Penelitian ini menggunakan metode survei menggunakan kuesioner data kualitatif. Sampel yang digunakan dalam penelitian berjumlah 45 orang responden. Hasil dari penelitian menunjukkan, bahwa instagram efektif dalam menstimulasi tahap perhatian, meningkatkan ketertarikan, menimbulkan keinginan untuk membeli hingga terjadinya tindakan untuk membeli produk. Karakteristik umumnya berkorelasi nyata dengan efektivitas instagram sebagai media promosi, hanya indikator usia dengan indikator interest, indikator tingkat Pendidikan dan pendapatan per bulan dengan indikator action yang tidak berkorelasi nyata. keterdedahan media sosial berkorelasi sangat nyata dengan efektivitas instagram sebagai media promosi.
Keyword: pandemic, promotion media, small and medium micro enterprises, instagram

Judul: The Effectiveness of Instagram as a Marketing Communication Media in Processed Food Products from Fishery Product of SMEs Si Petek
Abstrak: Produk pangan olahan hasil perikanan UMKM Si Petek memiliki nilai jual dan memerlukan sebuah kegiatan komunikasi pemasaran, salah satunya dilakukan melalui media sosial instagram. Tujuan penelitian ini yakni menganalisis efektivitas instagram sebagai media komunikasi pemasaran produk pangan olahan perikanan UMKM Si Petek. Responden penelitian ini berjumlah 45 orang yakni pelanggan Si Petek yang ditentukan melalui non probability sampling. Variabel yang digunakan dalam penelitian ini yaitu karakteristik responden (umur, jenis kelamin, jenis pekerjaan, pendidikan, pendapatan, dan domisili) serta karakteristik pesan media sosial instagram (kelengkapan informasi, kejelasan informasi, desain visual, tipografi, dan frekuensi pengiriman pesan). Untuk mengukur efektivitas media sosial instagram @sipetek.id menggunakan EPIC model (empathy, persuasion, impact, dan communication). Hasil penelitian menunjukkan terdapat hubungan nyata antara pendapatan dengan kelengkapan informasi. Selain itu, dimensi empati dapat memengaruhi frekuensi pengiriman pesan, dimensi persuasi hanya mampu memengaruhi tipografi, dimensi dampak mampu memengaruhi umur, frekuensi pengiriman pesan, dan tipografi, serta dimensi efektivitas komunikasi dapat memengaruhi umur dan tipografi., Processed food products from the Si Petek MSME fishery have a selling value and require a marketing communication activity, one of which is done through Instagram social media. The purpose of this study is to analyze the effectiveness of Instagram as a communication medium for marketing processed food products from SMEs Si Petek. Respondents in this study amounted to 45 people, namely Si Petek customers who were determined through non-probability sampling. The variables used in this study are the characteristics of the respondents (age, gender, type of work, education, income, and domicile) and the characteristics of Instagram social media messages (completeness of information, clarity of information, visual design, typography, and frequency of message delivery). To measure the effectiveness of social media Instagram @sipetek.id using the EPIC model (empathy, persuasion, impact, and communication). The results showed that there was a significant relationship between income and completeness of information. In addition, the dimension of empathy can affect the frequency of sending messages, the dimension of persuasion can only affect typography, the dimension of impact can affect age, frequency of delivery messages, and typography, and the dimension of communication effectiveness can affect age and typography.
Keyword: marketing communication, processed food products, social media instagram

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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