Judul: Daya Saing dan Faktor-Faktor yang Memengaruhi Ekspor Teh Indonesia di Negara Tujuan Ekspor Utama
Abstrak: Indonesia termasuk salah satu negara produsen dan eksportir teh terbesar di dunia. Namun, volume ekspor dan pangsa pasar teh Indonesia cenderung menurun, sedangkan negara eksportir lain cenderung meningkat. Kondisi pasar teh internasional juga mengalami over supply sehingga menuntut negara-negara eksportir teh termasuk Indonesia untuk dapat meningkatkan atau mempertahankan pasar yang dimilikinya. Penelitian ini bertujuan untuk (1) menganalisis daya saing komparatif dan kompetitif komoditas teh hijau dan teh hitam Indonesia di negara tujuan utama; (2) menganalisis faktor-faktor yang memengaruhi volume ekspor teh hijau dan teh hitam Indonesia di negara tujuan utama. Metode analisis menggunakan Revealed Comparative Advantages (RCA), Export Product Dynamic (EPD), dan gravity model. Hasil analisis RCA menunjukkan teh hijau dan teh hitam Indonesia memiliki keunggulan komparatif di lima negara tujuan utama. Hasil analisis EPD menunjukkan teh hijau Indonesia memiliki daya saing kompetitif di Polandia, Jerman, dan UAE, sedangkan teh hitam Indonesia tidak memiliki daya saing kompetitif di lima negara tujuan utama. Faktor-faktor yang memengaruhi volume ekspor teh hijau Indonesia adalah GDP riil per kapita dan jarak ekonomi, sementara untuk teh hitam adalah harga ekspor teh hitam, nilai tukar riil, dan jarak ekonomi.
Keyword: black tea, EPD, gravity model, green tea, RCA

Judul: Analisis Daya Saing dan Faktor-Faktor yang Memengaruhi Permintaan Ekspor Teh Hitam Indonesia ke Negara Tujuan Ekspor
Abstrak: Indonesia is one of black tea exporting countries in the world. The purposes of this research is to analyze the competitiveness and factors affecting demand for Indonesian exports of black tea in export destination countries. The analytical methods used in this study are Revealed Comparative Advantage (RCA), Export Product Dynamics (EPD) and gravity model analysis. The export destination countries of Indonesian black tea are Russian Federation, Pakistan, Malaysia, United Kingdom, United States, Germany, Poland, United Arab Emirates, Ukraine and Netherlands in the periods of 2007-2013. RCA analysis shows that black tea Indonesia has a high competitiveness in the export destination countries. EPD analysis reveals that Indonesian black tea export to Pakistan, Poland, Russian Federation and Ukraine is under the Rising Star, and United Arab Emirates and the United Kingdom is under the Falling Star, while Germany, Malaysia, Netherlands and the United States is under the Lost Opportunity. The results of the analysis of gravity models show that real GDP export destination countries, GDP per capita of Indonesia, the real exchange rate of export destinations, the price of black tea exports and economic distance are variables significantly influencing demand for black tea export.
Keyword: Bogor Agricultural University, RCA., gravity model, EPD, competitiveness, black tea

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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