Judul: Analisis Sistem Tataniaga Jeruk Siam di Desa Sumberagung, Kecamatan Sumberbaru, Kabupaten Jember, Jawa Timur
Abstrak: Citrus nobilis is one of the primary commodities in Jember, where this commodity is increasingly growing as it has a good prospect in the future. Citrus marketing system needs to be considered to increase the value added in an effort to increase the income of farmers as producers. Therefore, farmers should know about the efficient marketing channel to market their crops. The method was used to analyze the orange business administration systems are including qualitative and quantitative methods. Orange marketing in Sumberagung village covers marketing area of Jember, Jogjakarta, and Jakarta. The results of this analysis indicate that there are six marketing channels, where the sixth channel the most efficient channel based on the operational efficiency indicator where the value of marketing margin is Rp 4 416.67, the farmer's share is 62.14%, and the ratio of benefit to cost is 15.41. But, overall all of the marketing channels in Sumberagung village is quite efficient based farmer’s share value and the ratio of benefit to cost that quite large.
Keyword: fruit, orange, ratio i/Ci, farmer’s share, marketing margin, market eficiency analysis, marketing

Judul: Analisis Saluran dan Efisiensi Pemasaran Jeruk Siam di Desa Kacinambun Kecamatan Tigapanah Kabupaten Karo
Abstrak: Desa Kacinambun merupakan salah satu desa dengan kontribusi produksi jeruk siam terbesar di Kabupaten Karo. Permasalahan yang dihadapi petani adalah permasalahan proses produksi, perbedaan harga yang tinggi antara petani produsen dengan konsumen serta posisi petani sebagai price taker. Tujuan penelitian ini adalah (1) mengidentifikasi lembaga, fungsi, dan saluran pemasaran yang terbentuk; (2) menganalisis efisiensi saluran pemasaran jeruk siam. Metode analisis data yang digunakan adalah analisis deskriptif kualitatif dan analisis marjin pemasaran, farmer’s share, serta rasio keuntungan terhadap biaya. Hasil penelitian menunjukkan lembaga pemasaran jeruk siam terdiri dari pedagang pengumpul desa, pedagang besar, dan pedagang pengecer. Seluruh lembaga pemasaran melakukan fungsi pemasaran, yaitu fungsi pertukaran, fisik, dan fasilitas. Kedua saluran pemasaran yang tersedia dapat dikatakan kurang efisien. Saluran pemasaran 1 (petani-konsumen) dari segi indikator marjin pemasaran dan farmer’s share efisien karena memiliki nilai marjin pemasaran terendah dan farmer’s share tertinggi, namun dari segi R/C ratio kurang efisien karena memiliki R/C ratio dan pangsa pasar yang rendah. Sementara itu saluran pemasaran 2 (petani-pedagang pengumpul desa-pedagang besar-pengecer) dari segi indikator marjin pemasaran dan farmer’s share dapat dikatakan kurang efisien, namun memiliki R/C ratio yang tinggi dan pangsa pasar cukup besar. Kata kunci: farmer’s share, fungsi, lembaga, marjin, price taker., Kacinambun Village is one of the villages with the largest contribution to Siamese orange production in Karo Regency. The problems faced by farmers are problems in the production process, the high price difference between producing farmers and consumers and the position of farmers as price takers. The aims of this study were (1) to identify the institutions, functions and marketing channels formed; (2) analyzing the marketing channel efficiency of Siamese oranges. The data analysis method used is descriptive qualitative analysis and marketing margin analysis, farmer's share, and profit to cost ratio. The results showed that the Siamese orange marketing agency consisted of village collectors, wholesalers, and retailers. All marketing institutions carry out marketing functions, namely exchange, physical, and facility functions. The two available marketing channels can be said to be less efficient. Marketing channel 1 (farmer-consumer) in terms of indicators of marketing margin and farmer's share is efficient because it has the lowest marketing margin value and the highest farmer's share, but in terms of R/C ratio it is less efficient because it has a low R/C ratio and market share. Meanwhile, marketing channel 2 (farmer-rural collector-large trader-retailer) in terms of indicators of marketing margin and farmer's share can be said to be less efficient, but has a high R/C ratio and quite a large market share. Keywords: farmer’s share, function, institution, margin, price taker.
Keyword: farmer's share, function, institution, margin, price taker

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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