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 Sistem Tataniaga Mentimun di Desa Laladon, Kecamatan Ciomas, Kabupaten Bogor
Abstrak: Cucumber is one of the prime commodities in Indonesia. The fluctuating price of cucumber and high marketing margin between received price by farmers and price which is paid by consumers make the received farmer's share by farmers is relatively small. The purpose of this research is to identify the channels and marketing functions, market structure and conduct of marketing institutions, and to analyze the efficiency of marketing channels of cucumber based on marketing marjin, farmer's share, and the ratio of benefits to costs. The data were collected by observation and interview to farmers in Laladon village, Subdistrick Ciomas, Bogor Regency. The result of research stated that there were three marketing channels formed with different functions, different institutions, and different market structure on every channel. The analysis of the marketing efficiency concluded that marketing channel III is the most efficient channel because it has the lowest marketing marjin, highest farmer's share, and highest ratio of benefits to costs.
Keyword: system, marketing, Laladon village, efficiency, Cucumber

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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