Judul: Analysis of Indonesian Main Commodities Export Performance to ASEAN + 4 in 2010-2015
Abstrak: Indonesia sudahsejak lama melakukan perdagangan dengan berbagai Negara namun masih terbatas pada komoditas tertentu dan Negara mitra utama seperti Cina, AmerikaSerikat, Jepang, India dan Singapura. Negara yang potensial untuk dijadikan mitra diantaranya adalah negara ASEAN+4. Komoditas unggulan ekspor Indonesia ke ASEAN+4 yaitu fixed vegetable fats and oils (SITC 422), miscellaneous chemical products, n.e.s. (SITC 598), electrical apparatus (SITC 772) serta paper and paper board (SITC 641). Hasil analisis RCA menunujukkan komoditi SITC 422 dan 641 memiliki daya saing. Analisis ISP menunujukkan Indonesia sebagai eksportir komodti SITC 422 dan 641. Posisi pasar berdasarkan matriks EPD berbeda setiap komoditi tapi secra umum berada pada posisi falling star. Penelitian ini menggunakan pendekatan model permintaan ekspor untuk menganalisis faktor-faktor yang memengaruhi ekspor komoditas unggulan. Hasil analisis menunjukkan bahwa GDP per kapita riil negara tujuan, jarak ekonomi, harga ekspor riil, nilai tukar riil dan nilai RCA berpengaruh terhadap volume ekspor komoditas.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, ASEAN+4, main commodity, export deman model, RCA, ISP, EPD, Blackcampaign, Trade Remedies, Cross Section, Time Series

Judul: Analysis of the Efficiency and Determinants of Indonesia's Ten Largest Agricultural Commodities Exports to ASEAN+3 Countries
Abstrak: Ekspor Indonesia ke ASEAN+3 memiliki porsi yang sangat besar. Sektor pertanian menjadi salah satu sektor penting sebagai penyumbang surplus terhadap neraca perdagangan bahkan menjadi sektor yang berhasil bertahan ditengah pandemi Covid-19. Penelitian ini bertujuan untuk menganalisis determinan ekspor sepuluh komoditas pertanian terbesar Indonesia ke negara mitra dagangnya serta nilai efisiensi ekspornya. Metode yang digunakan adalah stochastic frontier gravity model dengan data panel berupa nilai ekspor sepuluh komoditas pertanian terbesar Indonesia ke 12 negara di kawasan ASEAN+3 periode 2000 – 2021. Hasil penelitian menunjukkan bahwa variabel GDP riil Indonesia dan GDP riil negara mitra dagang, trade openness dan nilai tukar riil negara mitra dagang berpengaruh positif terhadap nilai ekspor. Sedangkan, variabel jarak ekonomi berpengaruh negatif terhadap nilai ekspor. Rata-rata nilai efisiensi ekspor sepuluh komoditas pertanian terbesar Indonesia ke negara di ASEAN+3 yakni sebesar 0,37., Indonesia's exports to ASEAN+3 have a considerable portion. The agricultural sector has become one of the essential sectors as a surplus contributor to the trade balance. It has even become a sector that has managed to survive amid the Covid-19 pandemic. This study aims to analyze the determinants of exports of Indonesia's ten largest agricultural commodities to its trading partner countries and the value of their export efficiency. The method used is a stochastic frontier gravity model with panel data in the form of the export value of Indonesia's ten largest agricultural commodities to 12 countries in the ASEAN+3 region for the period of 2000 – 2021. The result showed that the average export efficiency value of Indonesia’s ten largest agricultural commodities to countries in ASEAN+3 is 0,37. Furthermore, the results showed that the variables of Indonesia's real GDP and the real GDP of trading partner countries, trade openness, and the real exchange rate of trading partner countries have positively affected on the export values. Meanwhile, the economic distance variable has a negative impact on export values.
Keyword: ASEAN+3, Efficiency Export, Stochastic Frontier Gravity Model, Ten Largest Agricultural Commodities

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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