Judul: Determinants of Farmers’ Decision to Take Credit and The Impact on Rubber Farming Performance
Abstrak: Karet adalah salah satu komoditas perkebunan yang banyak diekspor Indonesia. Namun produktivitasnya masih rendah, dimana kesulitan permodalan petani menjadi permasalahan utama dan salah satu cara penguatan permodalan adalah program kredit. Penelitian ini bertujuan untuk menganalisis faktor-faktor yang memengaruhi petani mengambil kredit dan dampaknya terhadap kinerja usahatani karet. Data yang digunakan merupakan data sekunder Survei Rumah Tangga Usaha Perkebunan Tahun 2014 berjumlah 19.229 petani, terdiri dari 355 petani mengambil kredit dan 18.874 petani tidak mengambil kredit. Metode yang digunakan adalah regresi logistik dan propensity score matching. Hasil penelitian menunjukkan bahwa variabel yang signifikan memengaruhi keputusan petani mengambil kredit, antara lain jenis kelamin, tingkat pendidikan, lokasi usahatani, keanggotaan koperasi, keanggotaan kelompok tani, dan kepemilikan lahan. Namun, variabel usia, jumlah tanggungan keluarga, penyuluhan, kemitraan, dan umur tanaman tidak berpengaruh signifikan terhadap keputusan petani mengambil kredit. Selain itu, kredit berdampak positif terhadap produksi, penerimaan, dan biaya usahatani karet, tetapi tidak berpengaruh signifikan terhadap produktivitas dan profit usahatani karet., Rubber is one of the plantation commodities which exported by Indonesia. But the productivity is low, that farmer’s capital difficulty is the main problem and credit is one of the way to solve it. This study aims to analyze the factors that influence farmers in taking credit and its impact on the performance of rubber farming. The data used is secondary data from the 2014 Plantation Business Household Survey with total of 19,229 farmers, consisting of 355 farmers taking credit and 18.874 farmers not taking credit. The method used are logistic regression and propensity score matching. The results showed that significant variables influenced farmers' decisions to take credit are gender, education level, farm location, cooperative membership, farmer group membership, and land ownership. However, age, number of family dependents, agricultural extension services, partnerships, and age of plant are not significant to farmer's decision to take credit. In addition, credit has positive impact on production, income, and expenditure of rubber farming, but it has no significant effect on productivity and profits of rubber farming.
Keyword: credit, farm performance, propensity score matching, rubber

Judul: The Effect of Credit on Technical Efficiency and Profits of Rice Field Farming in Kutai Kartanegara Regency
Abstrak: Kredit menjadi faktor penunjang yang penting pada kegiatan produksi. Pentingnya kredit sebagai faktor penunjang karena dapat menaikkan kebutuhan input produksi dan produktivitas pada usahatani. Selain itu, dapat memberikan kemudahan dalam kegiatan yang dapat meningkatkan produksi dan keuntungan usahatani sehingga terjadi pembentukan modal. Namun, tidak semua kredit yang diberikan dimanfaatkan oleh petani dalam kegiatan usahataninya. Penelitian ini bertujuan untuk menganalisis faktor-faktor yang mempengaruhi keputusan petani menggunakan kredit, menganalisis efisiensi teknis usahatani padi sawah pada petani kredit dan petani non kredit, dan menganalisis pengaruh kredit terhadap keuntungan usahatani padi sawah. Pengumpulan data dilakukan pada bulan Januari hingga Mei 2020 dengan penentuan responden menggunakan companion modeling melalui tanya jawab kepada petani dengan bantuan kuesioner, sehingga didapat jumlah responden untuk petani kredit sebesar 36 orang dan petani non kredit sebesar 66 orang. Keputusan petani menggunakan kredit dianalisis dengan analisis regresi logit, pengaruh kredit terhadap efisiensi teknis dianalisis dengan analisis fungsi Cobb-Douglas, dan pengaruh kredit terhadap keuntungan usahatani dianalisis dengan persamaan regresi berganda. Hasil penelitian menunjukkan menunjukkan bahwa petani kredit lebih efisien dibandingkan petani non kredit. Rata-rata tingkat efisiensi teknis petani kredit sebesar 0,93 sedangkan petani non kredit sebesar 0,87. Berdasarkan hasil penelitian, bahwa dengan menggunakan kredit terdapat peluang bagi petani, untuk memenuhi penyediaan input produksi yang diperlukan agar dapat meningkatkan produksinya, karena efisiensi teknisnya lebih tinggi dibandingkan dengan petani yang tidak menggunakan kredit. Keuntungan untuk petani kredit sebesar Rp7.755.852,59 dan keuntungan untuk petani non kredit sebesar Rp12.460.129,06 per musim tanam. Keuntungan yang diperoleh dari usahatani padi sawah dengan kredit lebih kecil dibandingkan keuntungan petani non kredit. Hal ini karena biaya yang dikeluarkan petani non kredit lebih rendah, sehingga keuntungan yang diperoleh tinggi., Credit is an important supporting factor in production activities. The importance of credit as a supporting factor because it can increase the need for production inputs and productivity in farming. In addition, it can provide convenience in activities that can increase production and farm profits so that capital formation occurs. However, not all of the credits given are used by farmers in their farming activities. This study aims to analyze the factors that influence the decision of farmers to use credit, analyze the technical efficiency of lowland rice farming on farmers who use credit and farmers who do not use credit, and analyze the effect of credit on the profits of lowland rice farming. Data collection was carried out from January to May 2020 with the determination of respondents using the companion modeling method through question and answer to farmers with the help of a questionnaire, the number of respondents for credit farmers was 36 people and non-credit farmers were 66 people. Farmers' decision to use credit was analyzed by logit regression analysis, the effect of credit on technical efficiency was analyzed by Cobb-Douglas function analysis, and the effect of credit on farm profits was analyzed by multiple regression equations. The results showed that farmers who used credit was more efficient than farmers who do not use credit. The average level of technical efficiency of credit farmers were 0,93 while farmers who do not use credit were 0,87. Based on the results of the
Keyword: efisiensi teknis, kredit, padi sawah, regresi, stochastic frontier

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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