Judul: Analisis daya saing, posisi, dan faktor-faktor yang mempengaruhi impor gula Indonesia
Abstrak: Permintaan gula dalam negeri yang tinggi menyebabkan impor menjadi pilihan utama saat produksi domestik tidak mampu menyuplai permintaan tersebut. Impor gula yang terus meningkat setiap tahunnya dapat menyebabkan ketergantungan impor dan merugikan perekonomian Indonesia. Penelitian ini bertujuan untuk menganalisis bagaimana daya saing komoditi, tingkat ketergantungan impor, serta faktor-faktor yang mempengaruhi impor gula dalam jangka panjang. Metode yang digunakan adalah Revealed Comparative Advantage (RCA), Import Dependency Ratio (IDR), dan Vector Error Correction Model (VECM). Data yang digunakan adalah data time series tahunan 1980-2015. Hasil penelitian menunjukkan bahwa industri gula Indonesia tidak berdaya saing dengan nilai RCA rata-rata dibawah satu. Posisi Indonesia adalah sebagai negara net importir dengan rasio ketergantungan impor antara 6 hingga 92 persen pertahun. Berdasarkan pengujian VECM, variabel yang berpengaruh signifikan terhadap impor gula dalam jangka panjang adalah PDB perkapita, tingkat inflasi, luas lahan tebu, nilai tukar Rupiah, dan harga gula domestik. Sementara itu variabel harga gula internasional dan produksi gula tidak berpengaruh secara signifikan terhadap impor gula baik dalam jangka pendek maupun jangka panjang. Kontribusi terbesar terhadap impor gula dimiliki oleh variabel nilai tukar Rupiah dengan kontribusi sebesar 23 persen. Kata
Keyword: Sugar Import, RCA, Import Dependency Ratio, VECM

Judul: Analisis Faktor-faktor yang Memengaruhi Impor Gula di Indonesia
Abstrak: High sugar imports lead to import dependence that affects the domestic sugar industry. The purpose of this study is to analyze the development of the sugar industry conditions in Indonesia, measure the sugar import dependency ratio and factors that affect the import of sugar in the long run. This study uses the Vector Error Correction Model (VECM), and annual time series data from 1980 to 2012. The results of this study shows that sugar consumption increasing 3.82 percent per year while the production growth of ups and downs with 2.06 percent per year and imports continued to fluctuate with 6.86 percent per year during the period 1980-2012. Indonesian sugar import dependency ratio is still quite high with an average value of 26 percent per year. Based on VECM test, variables that significantly affect the sugar import are domestic production, domestic consumption, domestic sugar prices, international sugar prices, exchange rates and import tariffs on sugar. Meanwhile sugarcane planting area variable does not significantly affect the import of sugar in both the short and long term.
Keyword: VECM, import dependency ratio, sugar imports

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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