Judul: Trade Competitiveness Diagnostic and Export Determinants of Indonesian Fruit Commodities
Abstrak: Ekspor buah-buahan Indonesia ditentukan oleh daya saing komoditas buahbuahan Indonesia dan faktor lainnya. Pada penelitian ini daya saing buah-buahan Indonesia dianalisis dengan metode Trade Competitiveness Diagnostic (TCD) yang meliputi Revealed Symmetric Comparative Advantage, Trade Balance Index, Intra Industry Trade Index, Trade Complementarity Index, serta Index of Export Market Penetration. Analisis data panel digunakan untuk menganalisis determinan yang memengaruhi nilai ekspor buah-buahan Indonesia ke negara tujuan. Hasil analisis TCD menunjukkan secara umum komoditas buah-buahan belum berdaya saing secara komparatif, bersifat net importir, memiliki penetrasi pasar yang rendah, serta masih bersifat inter industri (one way trade). Kendati demikian, buah-buahan Indonesia memiliki komplementaritas perdagangan yang tinggi. Selanjutnya, hasil analisis data panel menunjukkan determinan yang memengaruhi nilai ekspor buahbuahan Indonesia ke negara tujuan meliputi GDP riil negara tujuan, jarak ekonomi, kurs riil, harga ekspor dan RSCA., Indonesian fruit exports are determined by the competitiveness of the fruits among other factors. In this research, Indonesian fruit competitiveness is analyzed using the Trade Competitiveness Diagnostic (TCD) method which involves: Revealed Symmetric Comparative Advantage, Trade Balance Index, Intra Industry Trade Index, Trade Complementary Index, and the Index of Export Market Penetration. Panel data analysis is used to analyze the determinants that influence the export of fruits to the destination countries. TCD results show that in general fruits are not yet comparatively competitive, are net importers, have low market penetration power, and are still inter-industrialized (one way trade). Nevertheless, Indonesian fruits have high trade complementarity. Furthermore, panel analysis results show that the determinants that influence the export value of Indonesian fruits to destination countries include the destination country’s real GDP, economic distance, real exchange rate, export value, and RSCA.
Keyword: Buah-buahan, Data Panel, Trade Competitiveness Diagnostic

Judul: Trade Competitiveness Diagnostic and Export Determinants of Indonesian Vegetable Commodities
Abstrak: Komoditas sayuran merupakan salah satu komoditas ekspor hortikultura Indonesia memilki tren positif selama lima tahun terakhir. Penelitian ini menganalisis daya saing dan determinan ekspor sayuran Indonesia menggunakan metode Trade Competitiveness Diagnostics (TCD) yang terdiri dari beberapa indikator, di antaranya: Revealed Comparative Symmetric Advantage (RSCA), Trade Balance Index (TBI), Intra Industry Trade Index (IIT), Trade Complementarity Index (TCI), dan Index of Export Market Penetration (IEMP). Determinan ekspor dianalisis menggunakan metode regresi data panel. Hasil analisis TCD menunjukkan sebagian besar sayuran Indonesia belum memilki keunggulan komparatif, indeks penetrasi lemah, dan perdagangan hanya bersifat satu arah. Namun sayuran Indonesia menunjukkan posisi sebagai net-exporter dan memiliki share yang bersifat complementary dengan negara tujuan. Determinan yang berpengaruh terhadap nilai ekspor komoditas sayuran Indonesia di negara tujuan utama adalah harga ekspor, RSCA, dan TBI., Vegetable commodity is one of Indonesia's horticultural export commodities which has a positive trend over the last five years. This study analyzes the competitiveness and determinants of Indonesian vegetable exports using the Trade Competitiveness Diagnostics (TCD) method which consists of several indicators, including: Revealed Comparative Symmetric Advantage (RSCA), Trade Balance Index (TBI), Intra Industry Trade Index (IIT), Trade Complementarity Index (TCI), and Index of Export Market Penetration (IEMP). Export determinants were analyzed using panel data regression method. The results of the TCD analysis show that most Indonesian vegetables do not yet have a comparative advantage, the penetration index is weak, and trade is only one-way. However, Indonesian vegetables show a position as a net-exporter and have a share that is complementary to the destination country. The determinants that affect the export value of Indonesian vegetable commodities in the main destination countries are export prices, RSCA, and TBI.
Keyword: Panel Data Analysis, Trade Competitiveness Diagnostic, Vegetable

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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