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: Analisis Dayasaing Olahan Kakao Indonesia di Negara Tujuan Utama Ekspor setelah Penetapan Tarif Ekspor.
Abstrak: Indonesia merupakan salah satu negara dengan penghasil biji kakao terbesar di dunia. Penetapan tarif ekspor pada biji kakao diharapkan dapat meningkatkan ekspor kakao dalam bentuk olahan. Penelitian ini dilakukan untuk menganalisis dayasaing dan faktor-faktor yang memengaruhi ekspor kakao olahan Indonesia di negara tujuan utama ekspor. Berdasarkan hasil analisis RCA, kakao olahan Indonesia sudah berdayasaing cukup kuat di negara tujuan utama ekspor. Hasil analisis regresi data data panel menunjukkan bahwa faktor-faktor yang memengaruhi ekspor kakao pasta adalah volume ekspor, nilai tukar riil Indonesia dan penetapan tarif ekspor biji kakao. Pada kakao powder faktor-faktor yang memengaruhi adalah volume ekspor, harga ekspor, dan penetapan tarif biji kakao. Sedangkan pada kakao butter, faktor yang memengaruhi adalah volume ekspor dan nilai tukar riil Indonesia.
Keyword: dayasaing, ekspor, kakao, 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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