Judul: Struktur Pasar dan Daya Saing Produk Kakao Olahan Indonesia di Pasar Jerman
Abstrak: Indonesia merupakan eksportir utama produk kakao olahan yaitu produk cocoa paste (HS 1803), cocoa butter (HS 1804), dan cocoa powder (HS 1805). Pangsa pasar terbesar Indonesia berada di kawasan Uni Eropa dan salah satunya adalah Jerman. Jerman merupakan salah satu negara tujuan ekspor utama Indonesia dan importir utama kakao olahan sekaligus produsen serta konsumen utama cokelat di dunia. Penelitian ini bertujuan untuk menganalisis struktur pasar dan tingkat persaingan diantara eksportir utama di pasar Jerman. Selain itu, daya saing kakao olahan Indonesia dan potensi kerjasama Indonesia dengan Jerman dalam hal perdagangan kakao olahan juga dibahas dalam penelitian ini. Nilai Herfindahl Index (HI) dan Concentration Ratio (CR4) menunjukkan bahwa struktur pasar kakao olahan di Jerman cenderung oligopoli dengan tingkat persaingan antar eksportir yang ketat khususnya eksportir utama. Metode Revealed Comparative Advantage (RCA) menunjukkan bahwa kakao olahan Indonesia memiliki daya saing kuat di pasar Jerman (RCA>1). Selanjutnya, nilai Trade Complementarity Index (TCI) menunjukkan kesesuaian yang tinggi dalam struktur ekspor-impor kakao olahan Indonesia-Jerman sehingga ada potensi kerjasama antara Indonesia-Jerman dalam perdagangan produk kakao olahan.
Keyword: kakao olahan, struktur pasar, daya saing, RCA, TCI

Judul: Analisis Daya Saing Kakao Olahan Indonesia di Negara Tujuan Ekspor Utama
Abstrak: Indonesia merupakan salah satu negara produsen kakao terbesar di dunia sehingga memiliki potensi yang baik dalam meningkatkan ekspor kakao olahan. Penelitian ini bertujuan untuk (1) menganalisis keunggulan komparatif kakao olahan Indonesia di negara tujuan ekspor utama, (2) menganalisis keunggulan kompetitif kakao olahan Indonesia di negara tujuan ekspor utama, dan (3) menganalisis faktor-faktor yang mempengaruhi ekspor kakao olahan Indonesia di negara tujuan ekspor utama. Metode analisis yang digunakan adalah Revealed Comparative Advantage (RCA), Export Product Dynamic (EPD), Acceleration Ratio (AR), dan Gravity Model. Analisis RCA menunjukkan bahwa kakao olahan Indonesia berdaya saing kuat di negara tujuan ekspor utama. Analisis EPD menunjukkan bahwa posisi pasar ekspor kakao olahan Indonesia berada pada posisi Rising Star dan Lost Opportunity. Analisis AR menunjukkan bahwa Indonesia mampu merebut pasar kakao olahan di negara tujuan ekspor utama. Faktor-faktor yang mempengaruhi ekspor lemak kakao adalah GDP riil per kapita negara tujuan, GDP riil per kapita Indonesia, nilai tukar riil negara tujuan terhadap dollar AS, sedangkan untuk bubuk kakao adalah GDP riil per kapita negara tujuan, GDP riil per kapita Indonesia, nilai tukar riil negara tujuan terhadap dollar AS, dan jarak ekonomi., Indonesia is one of the biggest cocoa producers in the world so it has a great potential to increase processed cocoa export. This research aims to: (1) analyze the comparative advantage of Indonesian processed cocoa in the main export destination countries, (2) analyze the competitive advantage of Indonesian processed cocoa in the main export destination countries, and (3) analyze the factors that affect the export of Indonesian processed cocoa in the main export destination countries. The analytical methods are Revealed Comparative Advantage (RCA), Export Product Dynamic (EPD), Acceleration Ratio (AR), and Gravity Model. RCA analysis showed that Indonesian processed cocoa has strong competitiveness in the destination countries. EPD analysis showed that the market position of the Indonesian processed cocoa export is either Rising Star or Lost Opportunity. AR analysis showed that Indonesia has able to seize the export market for all processed cocoa in all destination countries. Variables that affect the export of cocoa butter are the real GDP per capita of the destination countries, the real GDP per capita of Indonesia, the real exchange rate, while for cocoa powder are the real GDP per capita of the destination countries, the real GDP per capita of Indonesia, the real exchange rate, and the economic distance.
Keyword: Acceleration Ratio (AR), export duty, Export Product Dynamic (EPD), Gravity Model, Revealed Comparative Advantage (RCA)

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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