Judul: Analysis of Beef Cattle Farm Business Based on Qualitative Factors Using Fishbone Diagram
Abstrak: Sapi potong merupakan nilai salah satu penghasil daging yang memiliki nilai ekonomi tinggi dan gizi. Konsumsi daging sapi di Indonesia selalu meningkat setiap tahunnya, seiring dengan peningkatan jumlah penduduk, peningkatan pendapatan dan kesejahteraan masyarakat. Penelitian ini bertujuan untuk menganalisis faktor-faktor kualitatif usaha pemeliharaan sapi potong dengan menggunakan diagram tulang ikan. Pengumpulan data dilakukan dengan melakukan wawancara dengan pemilik perusahaan, kemudian hasil wawancara tersebut dianalisis menggunakan diagram tulang ikan. Permasalahan yang dialami PT X dalam memperbaiki produktivas sapi pedaging yang rendah disebabkan oleh postur tubuh sapi kurus dan sapi yang mudah terserang penyakit (PMK, tanduk luka, scabies, pincang). Faktor yang paling memengaruhi produktivitas sapi pedaging pada usaha pemeliharaan sapi di PT X ini adalah faktor manusia., Beef cattle are one of the meat producers that have high economic and nutritional value. Consumption of beef in Indonesia continues to increase every year, along with an increase in population, increased income and welfare of the people. This study aims to analyze the qualitative factors of beef cattle rearing business using a fishbone diagram. Data collection was carried out by conducting interviews with company owners, then the results of these interviews will be analyzed using a fishbone diagram. The problems experienced by PT X in improving the low productivity of beef cattle are caused by lean body postures and cattle that are prone to disease (FMD, wound horns, scabies, lameness). The factors that most influence the productivity of beef cattle in the cattle rearing business at PT X is the human factor.
Keyword: diagram tulang ikan, ekonomi, sapi pedaging

Judul: Faktor – Faktor yang Mempengaruhi Usaha Ternak Sapi Potong di Desa Mangkai Lama Kecamatan Lima Puluh Kabupaten Batubara Provinsi Sumatera Utara
Abstrak: Farming system is a process of combining the factor of production such as land, livestock, labour, and capital to produce farm products. The success of beef cattle business depends on three elements; seed, feed, and management. Management includes the management of mating, feeding, housing, and cattle health. The purpose of this study is to analyze the factors that affect the beef cattle business in the village of Mangkai Lama, Lima Puluh Sub District, Batubara District using multiple linear regression analysis. Income servers as the dependent variable. Other side the independent variable is internal factors of farmer such as the number of livestock, education, age of farmer, farming experience, and number of family dependent. The factors that affect the beef cattle business in the village of Mangkai Lama, Lima Puluh Sub-District, Batubara District is the number of beef cattle and education level. Age of farmer, farming experience, and number of family dependent other side have no effect in the beef cattle business in the village of Mangkai Lama, Lima Puluh Sub District, Batubara District.
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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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