Judul: Keragaan usahatani dan efisiensi produksi jeruk keprok soe berdasarkan zona agroklimat di Provinsi Nusa Tenggara Timur
Abstrak: Keprok SoE mandarin is a high economic value commodity. It is expected that the commodity is a driven commodity for dryland farmers’ economy in East Nusa Tenggara Province. However, the mandarin production and its productivity are low due to improper input used, agroclimatic factors, farm size, low managerial skill and capability of farmers. This research investigates farm level productivity and technical efficiency, and their determinants in a sample of 360 high- and low-land keprok SoE mandarin producing farms in 12 villages in six sub districts of South Central Timor district in East Nusa Tenggara Province. This study used a Translog functional form using technical inefficiency effect model of stochastic production function approach, simultaneously applied to cross sectional data. Results indicate that keprok SoE mandarin farmer’s income, productivity and technical efficiency are low. Factors affecting productivity of mandarin in highland area are number of productive tree, compost and vegetative seed. While factors determining productivity in lowland area are age of tree, family labour and vegetative seed. Mean technical efficiency in the highland area, 65%, is greater than lowland area, 61%. This suggests that keprok SoE mandarin farmers may increase the productivity by as much as 35% in highland and 39% in lowland through more efficient use of production inputs. Smaller farm size of < 1 ha indicates lower technical efficiency level than bigger farm size of ≥ 1 ha in highland area. Furthermore, in highland area, estimated coefficients in the technical inefficiency effect model indicate positive effect and significant on the technical efficiency of experience, contacted with agricultural field officer, farmer age, other sources of income, selling method and farmer group. While, education factor gives negative effect on technical efficiency. All factors determining efficiency level in lowland producing farms give negative effects and are not significant, except for experience factor. Based on these findings, it can be said that agroclimatic zones do not affect technical efficiency, but they affect productivity performance. It is suggested that by improving factors such as input used, farmer knowledge and managerial skills, farm size, postharvest technology and marketing, development strategies and agroecological factors; the productivity and technical efficiency of keprok SoE mandarin in high- and low-land areas should be increased.
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Judul: Efficiency Analysis of Rose Farming in Central Java Province
Abstrak: Provinsi Jawa Tengah merupakan provinsi dengan nilai produksi mawar tertinggi kedua di Indonesia. Namun, produksi yang tinggi tersebut ternyata tidak diimbangi dengan tren produktivitas yang positif dan tingkat pendapatan yang tinggi pula. Permasalahan tersebut diduga berkaitan dengan efisiensi usahatani. Penelitian ini bertujuan untuk menganalisis faktor-faktor yang memengaruhi produksi mawar dan tingkat efisiensi teknis, alokatif, dan ekonomi usahatani mawar di Jawa Tengah beserta faktor-faktor yang memengaruhinya. Metode yang digunakan pada penelitian ini yaitu menggunakan Stochastic Frontier Analysis (SFA) serta penurunan biaya dual. Hasil penelitian ini menunjukan bahwa hanya tiga variabel yang berpengaruh secara nyata terhadap produksi mawar di Jawa Tengah, yaitu adalah luas lahan, jumlah tanaman, dan pupuk kimia. Selain itu, ditinjau dari tingkat efisiensinya, usahatani mawar di Jawa Tengah sudah dikatakan efisien secara teknis namun belum dikatakan efisien secara alokatif dan ekonomi dengan nilai rata-rata efisiensi teknis, alokatif dan ekonomi masing-masing sebesar 0,82; 0,33; dan 0,28. Faktor-faktor sosial ekonomi yang berpengaruh nyata terhadap inefisiensi teknis adalah sumber bibit, bantuan usaha, dan kemitraan. Sedangkan untuk variabel-variabel yang berpengaruh nyata terhadap inefisiensi alokatif dan ekonomi adalah proporsi sumber pembiayaan sendiri, proporsi hasil panen untuk dijual, dan kemitraan., Central Java is the province with the second-highest rose production value in Indonesia. However, this high production is not accompanied by a positive trend in productivity and a high level of income. The issue is assumed to be related to farming efficiency. This study aims to analyze the factors that influenced the production of roses and the level of technical, allocative, and economic efficiencies of rose farming in Central Java along with the factors that influenced them. This study employed Stochastic Frontier Analysis (SFA) and dual cost reduction methods. The findings of this study indicate that only three variables had a significant effect on rose production in Central Java, namely land area, number of plants, and chemical fertilizers. Furthermore, in terms of the level of efficiency, rose farming in Central Java had been said to be technically efficient but had not been considered to be efficient in terms of its allocation and economic factors with an average score of technical, allocative, and economic efficiencies of 0.82, 0.33, and 0.28. Socio-economic factors that significantly affected technical inefficiency were the source of seeds, business assistance, and partnership. Meanwhile, the variables that had a significant effect on allocative inefficiency and economic inefficiency were the proportion of self-financing sources, the proportion of crops for sale, and partnerships.
Keyword: Dual cost, Efficiency, Rose farming, 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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