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: Analisis Dampak Non-Tariff Measures dan Faktor-Faktor yang Memengaruhi Ekspor Buah-Buahan Indonesia ke Negara Tujuan
Abstrak: Buah-buahan merupakan salah satu komoditas yang menjadi unggulan dalam ekspor sektor hortikultura Indonesia. Adanya hambatan non tarif (non tariff measures/NTMs) dalam perdagangan internasional produk pertanian, khususnya pada buah-buahan Indonesia dapat membuat volume ekspor buah-buahan Indonesia ke negara tujuan mengalami penurunan. Lebih lanjut, hambatan non tarif yang sering diberlakukan adalah kebijakan Sanitary and Phytosanitary (SPS) dan Technical Barries to Trade (TBT). Pada penelitian ini dianalisis dampak NTMs serta faktor-faktor yang memengaruhi ekspor buah-buahan Indonesia pada periode 2010 hingga 2019 ke negara tujuan. Metode yang digunakan pada penelitan ini terdiri dari analisis deskriptif dengan menggunakan pendekatan inventory dan analisis data panel dengan menggunakan model gravity. Hasil analisis inventory menunjukkan bahwa komoditas buah-buahan Indonesia paling banyak dikenakan kebijakan SPS dengan jenis testing requirement. Selanjutnya, hasil estimasi model gravity menunjukkan GDP riil negara pengimpor, GDP riil Indonesia, populasi negara pengimpor, populasi Indonesia, jarak ekonomi, nilai tukar riil, dan coverage ratio SPS berpengaruh signifikan terhadap volume ekspor buah-buahan Indonesia., Fruits are one of the leading commodities in Indonesia's horticultural sector exports. The existence of non-tariff barriers (non-tariff measures/NTMs) in the international trade of agricultural products, especially Indonesian fruit has reduced the volume of Indonesian fruit exports to the destination countries. Furthermore, non-tariff barriers that are often applied are the Sanitary and Phytosanitary (SPS) and Technical Barriers to Trade (TBT) policies. This study analyzes the impact of NTMs and the factors that affect the Indonesian fruits exports in the period 2010 to 2019 to destination countries. The method used in this research consists of descriptive analysis using an inventory approach and panel data analysis using a gravity model. The results of the inventory analysis show that the most Indonesian fruit commodities are subject to the SPS policy with the type of testing requirement. Furthermore, the estimation results of the gravity model show that the real GDP of the importing country, the real GDP of Indonesia, the population of the importing country, the population of Indonesia, the economic distance, the real exchange rate, and the SPS coverage ratio have a significant effect on the volume of Indonesian fruit exports.
Keyword: export, fruits, gravity model, inventory approach, NTMs

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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