Judul: Daya Saing Kopi Arabika Java Preanger di Desa Suntenjaya Kecamatan Lembang Kabupaten Bandung Barat
Abstrak: Kopi (Coffea Spp L) termasuk komoditas utama dan unggulan perkebunan yang memiliki nilai ekonomis tinggi. Desa Suntenjaya Kecamatan Lembang Kabupaten Bandung Barat, menjadi salah satu penghasil Kopi Arabika Java Preanger (KAJP) di Jawa Barat. Petani kopi arabika Java Preanger menggunakan pupuk subsidi dari pemerintah, sehingga faktor biaya input tradable akan berpengaruh terhadap keunggulan kompetitif maupun komparatif budidaya kopi arabika Java Preanger. Penelitian ini bertujuan untuk (1) menganalisis keunggulan kompetitif dan komparatif komoditas kopi arabika Java Preanger di Desa Suntenjaya, (2) menganalisis dampak kebijakan pupuk subsidi pemerintah terhadap daya saing kopi arabika Java Preanger di Desa Suntenjaya. Penelitian ini menggunakan metode Policy Analysis Matrix (PAM). Hasil analisis PAM menunjukkan bahwa usaha tani kopi arabika Java Preanger di Desa Suntenjaya memiliki keunggulan kompetitif ditunjukkan dari nilai PCR (Private Cost Ratio) sebesar 0,486 dan memiliki keunggulan komparatif ditunjukkan dari nilai DRC (Domestic Ratio Cost) sebesar 0,054, serta dengan adanya subsidi pupuk dari pemerintah berpengaruh
Keyword: Java Preanger, Komparatif, Kompetitif, PAM

Judul: Supply Chain and Value Added Analysis of Arabica Java Preanger Coffee in Suntenjaya Village Lembang District
Abstrak: Desa Suntenjaya menghasilkan single origin Kopi Arabika Java Preanger dengan nama “Bell Stone”. Ketidakefisienan rantai pasok menyebabkan keuntungan petani cenderung rendah. Penelitian ini bertujuan untuk (1) menganalisis rantai pasok Kopi Arabika Java Preanger, (2) menganalisis kinerja rantai pasok Kopi Arabika Java Preanger, (3) menganalisis nilai tambah Kopi Arabika Java Preanger pada pengolah kopi. Penelitian ini menggunakan kerangka Food Supply Chain Network untuk menganalisis rantai pasok, analisis margin pemasaran, farmer’s share, dan B/C rasio untuk menganalisis kinerja rantai pasok, dan metode Hayami untuk menganalisis nilai tambah. Berdasarkan hasil penelitian, rantai pasok Kopi Arabika Java Preanger memiliki sasaran pasar dengan target yang jelas. Saluran satu relatif lebih efisien dengan margin terendah dan farmer’s share tertinggi masing-masing 97% dan 3% dengan B/C rasio sebesar 1,08 yang tersebar merata ke setiap lembaga pemasaran. nilai tambah terbesar dimiliki oleh Marlem Coffee yaitu sebesar Rp 23.980,88/kg dan keuntungan sebesar Rp 23.461,23/kg. Kata kunci: B/C rasio, farmer’s share, food supply chain network, margin pemasaran, metode Hayami Suntenjaya Village produces single origin Arabica Java Preanger Coffee with the name is “Bell Stone”. Supply chain inefficiency is cause farmer’s profit become low. This research aims to (1) analyze the supply chain of Arabica Java Preanger Coffee, (2) analyze the performance supply chain of Arabica Java Preanger Coffee, (3) analyze value added of Arabica Java Preanger Coffee in coffee processor. Analysis supply chain of Arabica Java Preanger Coffee through the Food Supply Chain Network framework. Supply chain performance is measured by marketing margins, farmer’s share, benefit and cost ratio. Value added aspect was analyzed by the Hayami method. The Food Supply Chain Network framework show that in general supply chain of Arabica Java Preanger Coffee has the target market with clear target. Channel 1 is relatively more efficient than other channels with the lowest margin and the highest farmer’s share of 97% and 3% with the ratio of benefit is 1,08 and cost spread evenly. The result show that Marlem Coffee has the highest value added and profit of Rp 23.980,88/kg and Rp 23.461,23/kg. Keywords: B/C rasio, farmer’s share, food supply chain network, margin marketing, Hayami method.
Keyword: B/C rasio, farmer’s share, food supply chain network, margin pemasaran, metode Hayami

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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