Judul: Dadih Business Development Strategy as West Sumatran Functional Food (Case Study Dadih Nagari Gadut)
Abstrak: Angka permintaan dadih terus mengalami penurunan, padahal dadih memiliki potensi pengembangan produk dan permintaan pangan fungsional diproyeksikan akan terus meningkat hingga tahun 2025. Penelitian ini bertujuan untuk mengetahui model bisnis dadih saat ini, mengidentifikasi permasalahan konsumen dadih, serta menyusun model bisnis dadih. Pengumpulan data dilakukan pada bulan Maret hingga Juli 2021 dengan menggunakan konsep pemikiran desain. Data primer diperoleh dari seorang produsen dadih di Nagari Gadut dan 20 orang konsumen dadih. Hasil penelitian menunjukkan model bisnis awal usaha dadih masih sangat sederhana. Permasalahan utama yang dirasakan oleh konsumen adalah kegiatan promosi yang kurang, lokasi penjualan yang susah dijangkau, rasa dadih yang asam dan tidak konsisten, aroma amis pada dadih, serta kemasan dadih yang tidak praktis dan tidak informatif. Penelitian menghasilkan prototype yang dapat dijadikan acuan perbaikan produk dan kanvas model bisnis akhir dinilai dapat diimplementasikan., The demand for dadih continues to decline, even though dadih has the potential for product development and demand for functional food is projected to continue to increase until 2025. This study aims to determine the current dadih business model, identify dadih consumer problems, and develop a dadih business model. Data collection was carried out from March to July 2021 using the concept of design thinking. Primary data were obtained from a dadih producer in Nagari Gadut and 20 dadih consumers. The results showed that the initial business model of the dadih business was still very simple. The main problems felt by consumers were lack of promotional activities, hard to reach sales locations, sour and inconsistent dadih taste, fishy dadih smell, as well as impractical and uninformative dadih packaging. This study developed a prototype that could be used as a reference for product improvement and the final business model canvas was considered implementable.
Keyword: business model canvas, design thinking, product development

Judul: Pengembangan Model Bisnis Produk Dadih Susu Sapi
Abstrak: Dadih is milk fermented product which reputed as one of each traditional healthy food from Indonesia that use milk and lactic acid bacteria as the main raw material. Based on the research that actual production fermented milk product in Indonesia was increased from year to year. Customer development could be one of the solution to know and fulfil customer needs taht use iteration concept until get the best decision. Business model canvas was a tool to combine and choose an idea to get the new concept dadih product. The last decision from iteration that had been done with a repetition would change dadih concept from founders mind became a product that got customer acceptance. Production cost calculation with 200 litre a day scale was got Rp. 6.000,- for the selling price. In investation criteria analiysis, dadih cow milk business project had passed and suitable because NPV and Net B/C value was more than one and IRR more than bank interest. From customer discovery step in customer validation for business model development was changed in channel, value proposition, customer relationship, and customer segment.
Keyword: validated business model., dadih, customer acceptance, cow milk, business model canvas

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: