Judul: Analisis Pengaruh Pandemi Covid-19 terhadap Ekspor Lada Hitam Indonesia
Abstrak: Akhir 2019, muncul pandemi Covid-19 yang menyerang dunia termasuk Indonesia. Pandemi berdampak pada perekonomian khususnya sektor ekspor. Salah satu komoditas ekspor, yaitu lada hitam bermanfaat untuk kesehatan. Penelitian ini bertujuan menganalisis daya saing serta pengaruh pandemi terhadap ekspor lada hitam. Metode untuk menganalisis daya saing adalah Revealed Comparative Advantage (RCA), Export Product Dynamic (EPD), dan X-Model Potential Exports. Metode untuk menganalisis pengaruh pandemi Covid-19 terhadap ekspor lada hitam adalah regresi data panel dengan time series 2012-2021 serta cross section tujuh negara. Analisis RCA menunjukkan Indonesia berdaya saing komparatif pada tujuh negara tujuan. Analisis EPD menunjukkan posisi rising star di Tiongkok, falling star di Singapura dan Belanda, lost opportunity di Vietnam dan Amerika Serikat, serta retreat di India dan Jerman. Analisis X-Model menunjukkan potensi pasar optimis di Tiongkok, potensial di Vietnam, Amerika Serikat, Singapura, dan Belanda, serta kurang potensial di India dan Jerman. Analisis data panel menunjukkan GDP riil, nilai tukar, jarak ekonomi, dan populasi berpengaruh positif terhadap ekspor lada hitam. Sedangkan harga ekspor dan pandemi Covid-19 tidak berpengaruh terhadap ekspor lada hitam.
Keyword: Black pepper, competitiveness, covid-19 pandemic, exports, panel data

Judul: Analysis Factors Affecting of the Competitiveness Indonesian Black Pepper in the International Market
Abstrak: Indonesia menjadi salah satu produsen dan pengekspor lada dunia. Hampir sebagian besar lada Indonesia diperuntukan untuk kebutuhan ekspor khususnya lada hitam. Namun, kontribusi lada hitam Indonesia di pasar dunia semakin menurun sehingga Indonesia tidak lagi menjadi eksportir nomor satu di dunia. Kekuatan daya saing terhadap suatu komoditas membuat suatu negara dapat melakukan ekspor komoditas ungggulannya. Tujuan penelitian ini adalah untuk menganalisis daya saing dan faktor-faktor yag memengaruhi daya saing lada hitam Indonesia di pasar internasional. Periode analisis yang digunakan pada penelitian ini yaitu dari tahun 2012 hingga 2019 dengan menggunakan metode Revealed Comparative Advantage (RCA) dan Korelasi Pearson. Dimana untuk menganalisis korelasi antara daya saing yang dihasilkan dari nilai RCA dengan beberapa faktor – faktor yang diduga memengaruhi daya saing lada hitam Indonesia di pasar internasional, yaitu volume ekspor lada hitam Indonesia (X1), harga internasional lada hitam Indonesia (X2), nilai tukar rupiah terhadap dolar (X3), serta inflasi tahunan Indonesia (X4). Hasil perhitungan RCA menujukan bahwa lada hitam Indonesia memiliki daya saing yang kuat di pasar internasional dengan rata-rata nilai RCA sebesar 7,54 serta hasil analisis korelasi Pearson menunjukan bahwa faktor volume ekspor lada hitam Indonesia dan harga internasional lada hitam Indonesia memiliki korelasi signifikan dengan daya saing lada hitam Indonesia di pasar internasional, sedangkan faktor nilai tukar dan inflasi tidak terdapat korelasi yang signifikan dengan daya saing lada hitam Indonesia di pasar Internasional., Indonesia is one of the pepper producer and exporter in the world. Most of Indonesia’s pepper is intended for export, especially black pepper. However, the contribution of Indonesian black pepper to the world market is decreasing so that Indonesia is no longer the number one exporter in the world. The strength of the competitiveness of a commodity allows a country to export its superior commodity. The purpose of this study is to analyze the competitiveness and the factors that influence the competitiveness of Indonesian black pepper in the international market. The periode of analysis used in this study from 2012 to 2019 and using the method of Revealed Comparative Advantage (RCA) and Pearson Correlation. Where to analyze the correlation between competitiveness resulting from the RCA value with several factors that are thought to affect the competitiveness of Indonesian black pepper in the international market, namely the export volume of Indonesian black pepper (X1), international price of Indonesian black pepper (X2), exchange rate rupiah against the dollar (X3), and Indonesia's annual inflation (X4). The results of the RCA calculation show that Indonesian black pepper has strong competitiveness in the international market with an average RCA value of 7.54 and the results of the Pearson Correlation analysis show that the export volume factor of Indonesian black pepper and the international price of Indonesian black pepper have a significant correlation with the competitiveness of Indonesian black pepper. the competitiveness of Indonesian black pepper in the international market, while the exchange rate and inflation factors have no significant correlation with the competitiveness of Indonesian black pepper in the international market.
Keyword: black pepper, competitiveness, export, pearson correlation, RCA

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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