Judul: Competitiveness, Dynamics, and Determinats of Indonesian Sport Footwear Exports to Main Destination Countries
Abstrak: Alas kaki merupakan komoditas unggulan ekspor Indonesia. Ekspor alas kaki Indonesia didominasi sepatu olahraga. Namun, Indonesia menghadapi persaingan ketat antar negara eksportir sepatu olahraga dan menurunnya pangsa pasar ke negara tujuan utama tahun 2018–2020. Tujuan penelitian ini menganalisis daya saing dan dikomparasikan dengan pesaing, dinamika, serta determinan ekspor sepatu olahraga Indonesia ke 10 negara tujuan utama periode 2011–2020. Metode penelitian ini yaitu RCA, EPD, X-Model, porter’s diamond dan regresi data panel. Hasil RCA menunjukkan sepatu olahraga Indonesia berdaya saing komparatif yang kuat. Hasil EPD menggambarkan posisi pasar rising star, falling star, dan retreat. Hasil X-Model menunjukkan pengembangan pasar optimis, potensial, dan kurang potensial. Hasil regresi data panel menunjukkan PDB riil Indonesia dan negara tujuan, harga, nilai tukar riil, daya saing, dan jarak ekonomi berpengaruh signifikan terhadap volume ekspor sepatu olahraga Indonesia. Hasil porter’s diamond menunjukkan daya saing kompetitif industri alas kaki Indonesia kuat berdasarkan pada sebagian besar faktor penting yang berpengaruh positif terhadap daya saing., Footwear is Indonesia's leading export commodity. Indonesian footwear exports are dominated by sports shoes. However, Indonesia faced stiff competition and declined market share to the main destination countries in 2018–2020. The purposes of this study is to analyze competitiveness and compare with competitors, dynamics, and determinants of Indonesian sports shoe exports to 10 main destination countries for the period 2011–2020. The research methods are RCA, EPD, X-Model, porter's diamond and panel data regression. The RCA results showed that Indonesian sports shoes had strong comparative competitiveness. The EPD results described the rising star, falling star, and retreat market positions. X-Model results showed an optimistic, potential, and less potential market development. The panel data regression result showed that Indonesia's and destination countries real GDP, prices, real exchange rates, competitiveness, and economic distance had a significant effect on export volume of Indonesian sports shoes. The porter's diamond results showed that the competitive competitiveness of Indonesian footwear industry is strong, based on most of the fundamental factors had a positive effect on competitiveness.
Keyword: EPD, Competitiveness, Panel Data, Sport Footwear Export, X-Model

Judul: Analysis of Indonesian Footwear Export Market Diversification and its Determinants
Abstrak: Alas kaki merupakan komoditas unggulan ekspor Indonesia. Namun, destinasi ekspor alas kaki Indonesia masih didominasi oleh beberapa negara sehingga rawan akan guncangan ekonomi global. Jika dibandingkan dengan negara pesaing yaitu China dan Vietnam, ekspor alas kaki Indonesia masih lebih rendah. Perlu dilakukan ekspansi pasar ekspor ke negara yang belum menjadi tujuan utama ekspor untuk mendorong kinerja perdagangan alas kaki Indonesia. Penelitian ini memiliki tujuan untuk menganalisis diversifikasi pasar ekspor alas kaki Indonesia dan determinannya. Metode STR digunakan untuk menganalisis negara tujuan ekspor, metode RCA, EPD, dan X-Model digunakan untuk mengetahui daya saing alas kaki Indonesia, dan regresi data panel digunakan untuk mengetahui faktor-faktor yang memengaruhi ekspor alas kaki Indonesia. Hasil penelitian memperlihatkan Indonesia memiliki daya saing yang kuat di negara Argentina, Austria, Brazil, Cili, Ceko, Yunani, Panama, Plandia, Spanyol, dan Swedia. Regresi data panel memperlihatkan bahwa nilai RCA, GDP negara tujuan ekspor, nilai tukar riil, dan harga ekspor memiliki pengaruh signifikan terhadap ekpor alas kaki Indonesia., Footwear is Indonesia, Footwear is Indonesia's leading export commodity. However, Indonesia's footwear export destinations are still dominated by several countries, making them vulnerable to global economic shocks. When compared with competing countries, namely China and Vietnam, Indonesia's footwear exports are still lower. It is necessary to expand the export market to countries that are not yet the main export destination to boost the performance of Indonesia's footwear trade. This research aims to analyze the diversification of the Indonesian footwear export market and its determinants. The STR method is used to analyze export destination countries, the RCA, EPD and X-Model methods are used to determine the competitiveness of Indonesian footwear, and panel data regression is used to determine the factors that influence Indonesian footwear exports. The research results show that Indonesia has strong competitiveness in the countries of Argentina, Austria, Brazil, Chile, Czech Republic, Greece, Panama, Poland, Spain and Sweden. Panel data regression shows that the RCA value, GDP of nonmain destination countries, real exchange rates, and export prices have a significant influence on Indonesian footwear exports.
Keyword: competitiveness, diversification, footwear

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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