Judul: The Competitiveness Analysis and The Factors Affecting Indonesian Footwear Export
Abstrak: Perdagangan ekspor yang dilakukan oleh Indonesia salah satunya ialah komoditi alas kaki yang juga merupakan satu dari sepuluh komoditi unggulan yang diekspor oleh Indonesia. Penelitian ini dilakukan untuk menganalisis daya saing ekspor alas kaki, menganalisis faktor-faktor yang memengaruhi ekspor alas kaki dan dinamika pasar ekspor alas kaki Indonesia ke negara tujuan. Data yang digunakan dalam penelitian ini adalah data sekunder yang diperoleh dari World Bank, ITC, CEPII dan WITS. Metode analisis menggunakan RCA dan EPD untuk mengetahui daya saing dan dinamika ekspor alas kaki, serta gravity model untuk menganalisis faktor-faktor yang memengaruhi ekspor alas kaki Indonesia. Hasil penelitian ini menunjukkan bahwa alas kaki Indonesia memiliki daya saing komparatif dengan nilai RCA yang lebih dari satu. Hasil estimasi EPD menunjukkan bahwa rata-rata terjadi pertumbuhan pangsa pasar dan permintaan ekspor alas kaki. Pada hasil gravity model menunjukkan bahwa variabel yang signifikan adalah GDP perkapita Indonesia, GDP perkapita negara tujuan, harga ekspor, populasi dan nilai tukar, sedangkan jarak ekonomi tidak berpengaruh.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, Export, EPD, Footwear, Gravity model, RCA, Analyze Competitiveness, Export Product, Demand, Time Series

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: 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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