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: Analysis of Trade Specialization and The Impact  of Non-Tariff Measures (NTM) on Indonesian Ginger Export to the Main Export  Destinations
Abstrak: Jahe merupakan komoditas andalan ekspor biofarmaka Indonesia tetapi kinerja ekspor jahe Indonesia justru mengalami penurunan selama beberapa tahun terakhir. Bahkan pada tahun 2019, Indonesia tercatat memiliki neraca perdagangan yang negatif dan menjadi negara pengimpor jahe. Penurunan ekspor jahe ini diduga disebabkan oleh ketidakmampuan produk untuk memenuhi persyaratan non-tariff measures (NTM) khususnya dalam bentuk sanitary and phytosanitary (SPS) dan technical barriers to trade (TBT) dari negara tujuan. Oleh karena itu, penelitian ini bertujuan untuk menganalisis spesialisasi perdagangan jahe Indonesia dan menganalisis dampak NTM terhadap ekspor jahe Indonesia ke negara-negara tujuan utama. Hasil dari Indeks Spesialisasi Perdagangan (ISP) menunjukkan bahwa Indonesia masih memiliki spesialisasi perdagangan sebagai eksportir jahe. Sementara hasil dari analisis regresi data panel dengan model gravity menunjukkan bahwa SPS berpengaruh positif dan TBT berpengaruh negatif terhadap ekspor jahe Indonesia ke negara-negara tujuan utama., Ginger is the main commodity of Indonesian herb export. However, Indonesia’s ginger export performance has declined over the last few years. Even in 2019, Indonesia had a negative trade balance and became a ginger importer country. The derivation of ginger export is thought to be caused by product inability to fulfil non-tariff measures (NTM) requirements especially for sanitary and phytosanitary (SPS) and technical barriers to trade (TBT). Therefore, this study aims to analyze the trade specialization of Indonesian ginger and analyze the impact of NTM on Indonesian ginger export to the main destination countries. The result of Indeks Spesialisasi Perdagangan (ISP) shows that Indonesia still have specialization in trading as a ginger exporter. Meanwhile the result of panel data regression analysis using gravity model shows that SPS has a positive effect and TBT has a negative effect on Indonesian ginger export to the main destination countries.
Keyword: Gravity Model, ISP, SPS, TBT

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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