Judul: Content Analysis of Posts to Users with the #UrbanFarmingIndonesia hashtag on Instagram Social Media During the Covid-19 Pandemic
Abstrak: Urban farming menghasilkan bahan makanan segar untuk pemenuhan ketersediaan pangan di perkotaan. Penelitian ini menganalisis variabel karakteristik akun, karakteristik produk dan klasifikasi urban farming. Tujuan penelitian ini adalah untuk menganalisis isi kiriman pada pengguna tagar #UrbanFarmingIndonesia selama pandemi Covid-19. Penelitian ini menggunakan desain eksploratif dengan metode analisis isi (content analysis). Sampel dipilih menggunakan purposive sampling sebanyak 50 akun Instagram yang menggunakan tagar #UrbanFarmingIndonesia. Data yang dikumpulkan dikategorikan dan diolah menggunakan Microsoft Excel, Qualitative Software Statistical Package for Social Science (SPSS) 23.0 dan Nvivo 12 Plus. Hasil analisis menunjukkan terdapat 76 persen akun bisnis dan 24 persen akun pribadi. Sebanyak 32 persen akun Instagram bisnis tidak mencantumkan informasi harga. Berdasarkan hasil tabulasi silang, semakin banyak pengikut maka semakin banyak pula kiriman pada akun tersebut. Jenis urban farming paling banyak ditemukan di media sosial Instagram adalah hidroponik dan konvensional/organik. Akun bisnis urban farming di Instagram harus menampilkan informasi selengkap-lengkapnya mengenai karakteristik produk dan toko. Konsumen harus mencari informasi sebanyak-banyaknya terkait toko dan produk sebelum melakukan pembelian produk urban farming di Instagram., Urban farming produces fresh food ingredients to fulfill food availability in urban areas. This study analyzes the variables of account characteristics, product characteristics and urban farming classifications. The purpose of this study was to analyze the content of posts by #UrbanFarmingIndonesia hashtag users during the Covid-19 pandemic. This study used an exploratory design with content analysis methods(contentanalysis).The sample was selected using purposive sampling as many as 50 Instagram accounts using the hashtag #UrbanFarmingIndonesia. The data collected was categorized and processed using Microsoft Excel, Qualitative Software Statistical Package for Social Science (SPSS) 23.0 and Nvivo 12 Plus. The results of the analysis show that there are 76 percent of business accounts and 24 percent of personal accounts. As many as 32 percent of business Instagram accounts do not include price information. Based on the results of the cross tabulation, the more followers, the more posts on the account. The most common types of urban farming found on Instagram social media are hydroponic and conventional/organic. Urban farming business account on Instagram must display complete information regarding product and store characteristics. Consumers should seek as much information as possible regarding shops and products before purchasingproducts urban farming on Instagram
Keyword: content analysis, covid-19, Instagram, hashtag, urban farming

Judul: Content Analysis Culinary Products Promotion on Social Media Instagram during COVID-19 Pandemic
Abstrak: Penetapan physical distancing di Indonesia untuk menekan angka penyebaran COVID-19, memunculkan wirausahawan kuliner baru yang memanfaatkan media sosial salah satunya Instagram. Proses promosi hingga transaksi dilakukan dengan konsumen secara online untuk menekan biaya pemasaran. Penelitian eksploratori ini bertujuan untuk mengidentifikasi karakteristik akun, kategori elemen kiriman, dan unsur promosi pada kiriman di akun Instagram bisnis kuliner dengan metode analisis isi. Teknik purposive sampling digunakan untuk mengambil data primer sebanyak 100 akun Instagram bisnis kuliner yang dibuat sejak bulan April 2020. Kategorisasi data dan pengolahan data dilakukan dengan menggunakan software Microsoft excel 2019, IBM SPSS Statistics 26, dan NVivo 12 untuk menganalisis data kualitatif. Hasil penelitian menunjukkan bahwa sebanyak 46 akun menjual makanan jenis appetizer. Sebesar 64% kiriman termasuk dalam kategori elemen foto produk. Elemen produk yang menjadi daya tarik kiriman belum didukung dengan kejelasan informasi yang baik dalam keterangan gambar, sehingga promosi produk kuliner tergolong kurang efektif.
Keyword: content analysis, COVID-19, culinary, instagram, promotion

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.
Keyword: