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: Efisiensi Teknis Produksi Usahatani Tebu Jawa – Luar  Jawa: Pendekatan Stochastic Frontier Analysis
Abstrak: Sugar cane is the main ingredient in the production of sugar which is consumed by the majority of Indonesian people. This commodity has a vital role in various aspects such as economic, social, and political. In providing the need for sugar, there needs to be good planning so that various upheavals do not occur. Sugarcane production produced by farmers for a decade has significantly increased to reach an average growth of 0.84 percent. Meanwhile, the sugarcane harvested area, which is the main factor in production, has dramatically decreased with an average growth of -0.05 percent since 2012. The decreasing harvested area is a concern in maintaining Indonesia's sugarcane production. However, the Sugar Factory (PG) requires a large harvest area for sugar production, accounting for 20 thousand ha to produce 10 thousand tons of sugar per day, thus causing a critical concern in population growth. In increasing production with continuously decreasing land conditions, it is necessary to use the Intensification method. The island of Java is dominating sugarcane production in Indonesia, which in the long term, it will no longer be able to contribute to production due to the conversion of agricultural land to non agricultural use and the level of technical efficiency in the current sugarcane farming production which has been almost well-developed. This condition is an alternative for the development of more agricultural areas outside Java Island. There are 10 provinces outside Java, namely Lampung, South Sumatra, Aceh, West Nusa Tenggara, Gorontalo, East Nusa Tenggara, North Sumatra, Bali, South Sulawesi and Southeast Sulawesi and 4 provinces in Java, namely East Java, Central Java, West Java, and DI Yogyakarta which have become targeted areas for the development of sugar cane based on PERMENTAN NO. 18 of 2018. This study aims to analyze and discuss the level of technical efficiency of sugar cane farming in Java and outside Java. The performance of sugarcane farmers in Java - Outside Java is seen from the level of technical efficiency which can indirectly describe the performance of sugarcane farmers in the development of sugarcane areas. The data used in this study is secondary data in the form of cross sections. The research data comes from the results of the 2014 Sugar Cane Business Household Survey which is part of the results of the 2013 Central Statistics Agency Agricultural Census with code ST2013-SKB.S. The research data were analyzed using a technical inefficiency model on the Cobb-Douglas stochastic frontier production function to see the characteristic and socioeconomic factors that influence inefficiency. Based on the research results in achieving maximum output, land, seeds with nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, and labor have a significant effect on Java Island, whereas the harvest area, seeds, and fertilizer elements of phosphorus become crucial factors outside Java Island. Among the variables concerned, land has the highest coefficient for Java Island. It shows that the increase in harvested area in Java is 4 times greater in producing production compared to outside Java. Increased harvested area is closely related to extensification. This is more likely to be done outside of Java. In this case,
Keyword: institution, stochastic frontier production function, sugarcane area, sugarcane farming, technical efficiency

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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