Judul: Income Analysis And Efficiency Of Carrot Farming In Pagar Wangi Urban Village, Dempo Utara Sub-District, Pagar Alam City
Abstrak: Kelurahan Pagar Wangi merupakan sentra produksi wortel di Kota Pagar Alam. Kelurahan Pagar Wangi adalah daerah dengan produksi dan luas lahan wortel terbesar. Dalam melakukan usahataninya, alokasi input yang digunakan masih belum sesuai dengan input optimal. Penelitian ini bertujuan untuk (1) menganalisis pendapatan usahatani wortel di Kelurahan Pagar Wangi, (2) menganalisis faktor-faktor yang memengaruhi produktivitas, (3) menganalisis efisiensi ekonomi. Penelitian ini menggunakan R/C ratio untuk mengetahui keuntungan usahatani wortel, fungsi produksi Cobb-Douglass dengan estimasi Ordinary Least Squares (OLS) untuk menganalisis faktor produksi yang memengaruhi produktivitas, dan metode Nilai Produk Marginal (NPM) untuk mengetahui efisiensi ekonomi. Hasil penelitian menunjukkan bahwa nilai R/C ratio usahatani wortel di Kelurahan Pagar Wangi masih menguntungkan walaupun belum optimal. Faktor-faktor yang berpengaruh signifikan terhadap produktivitas usahatani wortel adalah benih, pupuk kandang, dan pupuk NPK. Faktor produksi yang belum efisien pada usahatani wortel yaitu benih sehingga perlu untuk ditambah. Selanjutnya, faktor produksi yang tidak efisien yaitu pupuk kandang dan pupuk NPK sehingga perlu untuk dikurangi., Center of carrot production in Pagar Alam City is Pagar Wangi Urban Village. Pagar Wangi Urban Village is the area with the largest carrot land and amount of production. The allocation of inputs used in farming is still not in line with the most optimal input. The research aim to (1) analyze the income of carrot farming in Pagar Wangi Urban Village, (2) analyze the factors that affect the productivity, (3) analyze the economic efficiency. This research uses the R/C ratio to determine the benefits of carrot farming, the Cobb-Douglass Production function with Ordinary Least Squares (OLS) estimation to analyze the factors that affect the productivity, and the Value Marginal Product (VMP) to determine the economic efficiency. The results showed that the R/C value of the carrot farming in Pagar Wangi Urban Village is still profitable although not optimal. The factors that had a significant effect on the productivity of carrot farming was seeds, animal manure, and NPK fertilizer. Input that are not efficient yet in carrot farming are seeds so they need to be added. Furthermore, the inefficienct input in carrot farming are NPK fertilizer and animal manure so they need to be reduced.
Keyword: income analysis, OLS, productivity, R/C ratio, VMP

Judul: Economic Efficiency Analysis of Bell  Pepper Farming in Pasirlangu Village, Cisarua District, West Bandung Regency
Abstrak: Desa Pasirlangu merupakan sentra produksi paprika di Kecamatan Cisarua. Walau begitu usahatani paprika di Desa Pasirlangu belum mencapai produksi optimal yang dapat dicapai. Penelitian ini bertujuan untuk (1) menganalisis faktor-faktor yang memengaruhi produktivitas, (2) menganalisis efisiensi ekonomi, (3) menganalisis pendapatan usahatani paprika di Desa Pasirlangu. Penelitian ini menggunakan metode Ordinary Least Squares (OLS) untuk mengetahui faktor-faktor yang memengaruhi produktivitas, metode Nilai Produk Marginal (NPM) untuk mengetahui efisiensi ekonomi, dan R/C ratio untuk mengetahui keuntungan usahatani paprika. Hasil penelitian menunjukkan bahwa faktor-faktor yang berpengaruh signifikan terhadap produktivitas usahatani paprika adalah tenaga kerja dan benih. Faktor produksi yang belum efisien pada usahatani paprika yaitu benih dan arang sekam sehingga perlu untuk ditambah. Selanjutnya, faktor produksi yang tidak efisien pada usahatani paprika yaitu tenaga kerja, pupuk AB Mix dan pestisida sehingga perlu untuk dikurangi. Nilai R/C ratio usahatani paprika menunjukkan bahwa usahatani paprika di Desa Pasirlangu masih menguntungkan walaupun belum optimal., Center of bell pepper production in Cisarua District is Pasirlangu Village. However, bell pepper farming in Pasirlangu Village has not reached yet the optimal production that can be achieved. This research aims to (1) analyze the factors that affect the productivity, (2) analyze the economic efficiency, (3) analyze the income of bell pepper farming in Pasirlangu Village. This research uses the Ordinary Least Squares (OLS) method to determine the factors that affect the productivity, the Value Marginal Product (VMP) to determine the economic efficiency, and the R/C ratio to determine the benefits of bell pepper farming. The results showed that the factors that had a significant effect on the productivity of bell pepper farming were labor and seeds. Input that are not efficient yet in bell pepper farming are seeds and husk charcoal, so they need to be added. Furthermore, the inefficient input in bell pepper farming are labor, AB Mix fertilizer and pesticides, so they need to be reduced. The R /C value of the bell pepper farming ratio shows that the bell pepper farming in Pasirlangu Village is still profitable although not optimal.
Keyword: analisis pendapatan, NPM, OLS, produktivitas, R/C ratio, income analysis, OLS, productivity, R/C ratio, VMP

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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