Judul: Daya Saing Ubi Kayu Olahan Kering Indonesia di Pasar Internasional
Abstrak: Indonesia is the third largest exporter of cassava dried in the world. More than 80 percent of Indonesia’s cassava dried product are exported to China. Inspite of the productivity of Indonesia cassava that is increasing in rate of 5.22 percent per year, the export volume has decreased in rate of -4.4 percent per year. The purpose of this study is to analyze the market share behavior and the comparative advantage of Indonesia cassava dried product in the International market. The time series data used in this study and the Revealed Comparative Advantage (RCA) method used to analyze the data. Market share of cassava dried Indonesia in China around 1 to 8 percent (2001-2013), with -8 percent/year growth rate. It means Indonesia market share has dropped. Currently, Indonesia cassava dried market share in China around 1percent. Thailand is the biggest competitor of cassava dried Indonesia Cassava dried Indonesia has a comparative advantages in the international market (2004-2011), depend on RCA value which is more than 1. The RCA value of cassava dried Indonesia around 8.40 (2004) to18.38 (2010).
Keyword: Bogor Agricultural University (IPB), RCA, Comparative Advantages, Cassava

Judul: Analisis Kinerja Ekspor Ubi Kayu (Cassava) Indonesia ke Negara tujuan Ekspor
Abstrak: Indonesia merupakan tiga besar negara pengekspor ubi kayu di dunia yang memberikan peluang bagi Indonesia untuk menguasai pangsa pasar dunia. Tujuan dari penelitian ini adalah untuk menganalisis daya saing dan faktor–faktor yang memengaruhi permintaan ekspor ubi kayu Indonesia ke negara tujuan. Negara yang dianalisis adalah China, Korea, Amerika Serikat, Belanda, Brunei Darussalam, Singapura, Inggris, Australia, Malaysia, dan Hongkong pada periode 2001-2014. Metode yang digunakan dalam analisis adalah Revealed Comparative Advantage (RCA), Export Product Dynamic (EPD), dan gravity model. Hasil analisis RCA menunjukkan bahwa ubi kayu Indonesia berdaya saing di negara tujuan. Sedangkan hasil analisis EPD komoditas ubi kayu Indonesia berada pada posisi rising star untuk negara Australia, Amerika Serikat, Belanda, dan Singapura. Terdapat lima negara pada posisi falling star yaitu Brunei Darussalam, Korea, Inggris, Malaysia, Hongkong, dan pada posisi retreat adalah China. Pada hasil analisis gravity model menunjukkan bahwa kelima variabel berpengaruh secara signifikan terhadap permintaan ekspor ubi kayu Indonesia, yaitu jarak ekonomi, nilai tukar riil, GDP riil negara tujuan, populasi, dan harga ekspor riil.
Keyword: Daya saing, EPD, gravity model, RCA, ubi kayu

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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