Judul: Analysis of Factors Affecting Production an Income of Sugarcane in East Java Province
Abstrak: Meningkatnya konsumsi gula di Indonesia meningkatkan permintaan gula, sehingga diperlukan peningkatan produksi tebu nasional. Namun produksi tebu setiap tahunnya cenderung menurun sehingga Indonesia masih perlu mengimpor gula, terutama gula mentah. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi produksi dan menganalisis pendapatan petani tebu di Jawa Timur. Penelitian ini menggunakan data 2909 petani pada Sensus Pertanian 2013 Badan Pusat Statistika. Pendapatan usahatani dianalisis dengan R/C yang dibedakan menurut luas lahan arealnya. Faktor-faktor yang memengaruhi produksi tebu dianalisis menggunakan fungsi produksi Cobb Douglass. Hasil penelitian menunjukan bahwa luas lahan, bibit, pupuk unsur N, dan tenaga kerja memengaruhi produksi tebu. Rasio R/C menunjukan bahwa usahatani tebu dengan lahan sempit lebih efisien. Biaya tenaga kerja merupakan biaya terbesar untuk pertanian tebu lahan besar. Hasil penelitian menunjukan bahwa pemberian kredit produksi diperlukan untuk usahatani tebu skala besar., The increasing consumption of sugar in Indonesia increases the demand for sugar, so it is necessary to increase national sugarcane production. However, sugarcane's annual production tends to decline. Therefore Indonesia still needs to import sugar, especially raw sugar. The research aims to determine the factors that affect the production and analyze sugarcane farmers' income in East Java Province. This study used 2909 farmer’s data of Agricultural Census 2013, Central Bureau of Statistics. Farm income was analyzed using R/C analysis, which is differentiated according to its area. The factors affecting sugarcane production were analyzed using the Cobb-Douglas production function. The results showed that area, seeds, nitrogen unsure fertilizer, and labor affected sugar cane production. The R/C ratio indicated that small-size sugarcane farming was more efficient. The cost of hired labor was the highest cost for large-size sugarcane farming. This finding implies that production credit provision is needed for extensive sugarcane farming.
Keyword: agriculture, cost structure, land area, sugar cane

Judul: The Affecting Factors of Sugar Production in Indonesia due to National Sugar Self Sufficiency
Abstrak: Untuk memenuhi peningkatan konsumsi gula, pemerintah sedang gencar mendorong peningkatan produksi gula dengan target dapat berswasembada gula nasional. Akan tetapi, produktivitas gula saat ini tergolong rendah, dan produksi gula pun mengalami tren penurunan setiap tahunnya. Tujuan penelitian ini yaitu mendeskripsikan perkembangan agribisnis gula, menganalisis faktor-faktor yang memengaruhi produksi gula di Indonesia, dan meramalkan pencapaian swasembada gula Indonesia tahun 2025. Data yang digunakan berupa data runtun waktu dari tahun 1966-2019 dan dianalisis menggunakan metode VECM. Hasil analisis menunjukkan bahwa pada jangka pendek, produksi gula dipengaruhi oleh luas areal panen tebu dan konsumsi gula, sedangkan pada jangka panjang produksi gula dipengaruhi oleh konsumsi gula, impor gula, dan harga GKG. Peramalan hingga tahun 2025 menunjukkan bahwa ketergantungan Indonesia terhadap gula impor cenderung meningkat, sehingga Indonesia tidak dapat memenuhi target swasembada gula tahun 2025., In order to fulfill the increasing of sugar consumprtion, government is aggressively encouraging an increase in sugar production to achieve sugar selfsufficiency. However, the sugar production still has low productivity, and decreasing trend each year. This study aims to describe the growth of sugar agribusiness, analyze the affecting factors of sugar production, and forecast the achievement of sugar self-sufficiency in 2025. The data has been used in this study is time series data from 1966 until 2019, and analyzed by VECM method. The result of the analysis shows that, in the short term sugar production are affected by sugarcane harvest area and sugar consumption, while in long term, sugar production are affected by sugar consumption, sugar import, and price of paddy. Forecasting until 2025 shows that Indonesia's dependence on imported sugar tends to increase, so that Indonesia cannot achieve the sugar self-sufficiency target in 2025.
Keyword: production, self sufficiency, sugar, VECM

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.
Keyword: