Judul: Trade Competitiveness Diagnostic and Determinant of Indonesian Spice Exports Commodities
Abstrak: Salah satu komoditas unggulan ekspor Indonesia yang bernilai tinggi adalah rempah-rempah. Penelitian ini bertujuan untuk menganalisis daya saing dan determinan dari rempah Indonesia di negara tujuan utama pada periode 2017-2021. Berdasarkan hasil analisis menggunakan pendekatan Trade Outcome Analysis dari Trade Competitiveness Diagnostic (TCD) yang terdiri dari beberapa indikator, antara lain: 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) dapat diketahui bahwa rempah Indonesia sebagian besar memiliki keunggulan komparatif dan berdaya saing tinggi namun aktivitas perdagangan komoditas tersebut cenderung masih satu arah dengan daya penetrasi pasar rendah. Meskipun demikian, Indonesia menunjukkan posisi sebagai net-exporter dan dapat memenuhi permintaan di negara tujuan dengan baik. Hasil analisis data panel menunjukkan bahwa harga ekspor, GDP riil Indonesia, nilai tukar, jumlah populasi, nilai indeks RSCA, serta TBI berpengaruh signifikan. Sedangkan, GDP riil negara tujuan dan jarak ekonomi tidak berpengaruh signifikan terhadap ekspor rempah-rempah Indonesia ke negara tujuan utama., One of Indonesia's high-value export commodities was spices. This study aimed to analyze the competitiveness and determinants of Indonesian spices in the main destination countries during the period of 2017-2021. Based on the analysis using the Trade Outcome Analysis approach from Trade Competitiveness Diagnostic (TCD) consisting of several indicators, such as 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), it was observed that Indonesian spices mostly had comparative advantages and high competitiveness, but trade activities for the commodity tended to be one directional with low market penetration. Nevertheless, Indonesia showed a position as a net exporter and could fulfill demand in destination countries well. Panel data analysis showed that export prices, Indonesia's real GDP, exchange rate, population, RSCA index value, and TBI had a significant effect. Meanwhile, the real GDP of destination countries and economic distance did not significantly affect Indonesia's spice exports to the main destination countries.
Keyword: Panel Data, Spices, TCD

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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