Judul: Faktor-Faktor yang Memengaruhi Volume Ekspor Jahe Indonesia
Abstrak: Indonesia merupakan salah satu produsen dan pengekspor jahe di pasar global. Permintaan jahe yang tinggi di pasar global selama periode 2013 sampai 2019 memberi peluang besar bagi Indonesia sebagai eksportir jahe. Namun, di periode yang sama ekspor jahe Indonesia justru menurun drastis. Penurunan volume ekspor jahe Indonesia dapat disebabkan oleh berbagai faktor. Penelitian ini bertujuan untuk menganalisis faktor-faktor yang memengaruhi volume ekspor jahe Indonesia selama periode 2013 sampai 2019 dengan cakupan penelitian meliputi 6 negara tujuan ekspor jahe Indonesia; Bangladesh, Malaysia, Singapura, Jepang, Amerika Serikat dan Belanda. Metode yang digunakan adalah analisis deskriptif melalui pendekatan inventory (coverage ratio) dan regresi data panel. Hasil estimasi menunjukkan bahwa nilai tukar dan populasi negara tujuan berpengaruh positif terhadap ekspor jahe, sedangkan GDP riil negara tujuan, harga ekspor jahe dan bentuk kebijakan non tarif Technical Barrier to Trade (TBT) berpengaruh negatif. Bentuk kebijakan non tarif Sanitary and Phytosanitary (SPS) tidak berpengaruh terhadap ekspor jahe., Indonesia is one of the producers and exporters of ginger in the global market. High demand for ginger in the global market during the period 2013-2019 provides opportunities for Indonesia as a ginger exporter. However, at the same period Indonesian ginger exports have declined significantly. There are several factors that affect the decline of Indonesian ginger export volume. This research aims to analyze the factors that affect the volume of Indonesian ginger exports during the period 2013-2019 with the scope of the study covering 6 export destinations of Indonesian ginger; Bangladesh, Malaysia, Singapore, Japan, the United States and the Netherlands. This study used a descriptive analysis method based on inventory approach (coverage ratio) and panel data regression. The result shows that the exchange rate and the population of the destination countries have a positive effect on ginger exports, while the real GDP of the destination countries, ginger export prices and the Technical Barrier to Trade (TBT) of non-tariff policies have a negative effect. The Sanitary and Phytosanitary (SPS) of non-tariff policies have no effect on ginger exports.
Keyword: Coverage Ratio, Export, Ginger, Panel Data

Judul: Analisis Daya Saing serta Faktor-faktor yang Memengaruhi Permintaan Jahe dan Temulawak Indonesia di Lima Negara Tujuan Ekspor
Abstrak: Ginger and curcuma export demand increases with the proliferation of herbal medicine and cosmetics industries as well as changes in lifestyle of the world community to prioritize natural products rather than chemical. The purpose of this study is to analyze the development of exports, the competitiveness, the factors that affect the demand for exports, and a strategy to improve the competitiveness of Indonesian ginger and curcuma in five destination countries. This study uses descriptive analysis, RCA (Revealed Comparative Advantage), EPD (Export Product Dynamic), X-model potential export products, panel data, and Porter's Diamond. The results showed: (1) The development of the export value of Indonesian ginger and curcuma tends to fluctuate. (2) Ginger has a comparative advantage only in the Netherlands, in the same way curcuma in the United States, the Netherlands and Singapore, but in almost all sample countries, ginger and curcuma have a market position "Rising star" except in Japan, namely Lost Opportunity. (3) The variables that affect the demand for exports of ginger and curcuma are GDP riil destination countries per capita, the population of the country of destination, and economic distance. (4) strategies that can be done is to increase the competitiveness of commodities ginger and curcuma Indonesia by doing cluster approach in the development of the industry and do the increases in factor conditions and corporate strategy, structure and rivalry.
Keyword: ginger, demand for export, curcuma, competitiveness

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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