Judul: Competitivenes of Indonesian Gum Rosin in Global Market in the Period 2004-2020
Abstrak: Indonesia merupakan negara produsen terbesar ketiga setelah China dan Brazil yang menyumbangkan lebih dari 10% produksi gondorukem dunia pada tahun 2019. Indonesia juga menduduki urutan kedua setelah Brazil sebagai negara pengekspor komoditas gondorukem terbesar di dunia. Sejak tahun 2015 perkembangan ekspor gondorukem Indonesia menunjukkan tren yang menurun meskipun masih tetap merupakan negara utama di pasar gondorukem internasional. Penelitian ini bertujuan untuk menganalisis daya saing komparatif dan kompetitif serta faktor-faktor yang mempengaruhi pertumbuhan ekspor gondorukem Indonesia pada periode 2004-2020. Metode analisis yang digunakan berturut-turut adalah Revealed Comparative Advantage, Indeks Spesialisasi Perdagangan, dan Constant Market Share. Hasil penelitian menunjukkan bahwa komoditas gondorukem Indonesia selama periode 2004-2020 memiliki daya saing komparatif yang kuat seperti yang ditunjukkan oleh nilai indeks RCA berkisar 5,5-19,4 dan juga daya saing kompetitif kuat seperti yang ditunjukkan oleh nilai indeks ISP berkisar 0,78-0,97. Indonesia telah mencapai tahap kematangan di pasar internasional pada periode 2004-2020. Di samping faktor daya saing, faktor pertumbuhan standar dan faktor distribusi pasar berpengaruh positif terhadap pertumbuhan ekspor gondorukem Indonesia pada periode 2004-2020., Indonesia was the third largest producer country after China and Brazil that contributed more than 10% of the world's gum rosin production in 2019. Indonesia was also ranked second after Brazil as the largest gum rosin commodity exporter in the world. Since 2015 Indonesian’s gum rosin exports had a declining trend even though Indonesia was still the main exporter country in the international gum rosin market. The purpose of this study were to analyze the comparative and competitive advantages as well as factors influencing the growth of Indonesia's gum rosin exports in the period 2004-2020. The analytical methods used were Revealed Comparative Advantage, Trade Specialization Index, and Constant Market Share, respectively. The results showed that the Indonesian gum rosin commodity during the period 2004-2020 had a strong comparative advantage as indicated by RCA index value ranging from 5,5-19,4 and also a strong competitive advantage as indicated by the ISP index value ranging from 0,78-0,97. Indonesian reached the maturity stage in the international market for the 2004-2020 period. In addition to competitiveness factor, market growth and market distribution factors had a positive influence on Indonesia's gum rosin export growth for the period 2004-2020.
Keyword: Constant market share, export, gum rosin, trade specialization index, revealed comparative advantage

Judul: Analisis Daya Saing Ekspor Produk Rotan  Indonesia di Pasar Internasional Periode 2017- 2021
Abstrak: Indonesia merupakan negara eksportir utama produk rotan di dunia, namun persaingan cukup berat dari negara China yang menggunakan rotan sintetis perlu diperhatikan. Penelitian ini bertujuan untuk menganalisis daya saing komparatif dan kompetitif serta faktor apa saja yang mempengaruhi pertumbuhan ekspor produk rotan Indonesia periode 2017-2021. Metode yang digunakan berturut-turut adalah Revealed Comparative Advantage, Indeks Spesialisasi Perdagangan, dan Constant Market Share. Hasil penelitian menunjukkan ekspor produk rotan Indonesia periode 2017-2021 memiliki keunggulan komparatif yang kuat yang ditunjukkan oleh nilai indeks Revealed Comparative Advantage berkisar 11,38- 80,63, dan memiliki keunggulan kompetitif dan berada pada tahap kematangan yang ditunjukkan oleh nilai Indeks Spesialisasi Perdagangan berkisar 0,89-1. Analisis CMS menunjukkan bahwa faktor pertumbuhan standar, komposisi komoditas, dan distribusi pasar berpengaruh positif, sedangkan faktor daya saing berpengaruh negatif terhadap pertumbuhan ekspor produk rotan Indonesia periode 2017-2021., Indonesia is a major exporter of rattan products in the world, but competition from China which uses synthetic rattan needs to be considered. This study aims to analyze the comparative and competitive advantages as well as factors affecting the growth of Indonesian rattan product exports in the period 2017-2021. The methods used are, respevtively, Revealed Comparative Advantage, Trade Specialization Index, and Constant Market Share. The results showed that the export of Indonesian rattan products for the 2017-2021 period had a strong comparative advantage as indicated by the Revealed Comparative Advantage index value ranging from 11.38- 80.63, and a competitive advantage at the maturity stage as indicated by the Trade Specialization Index value ranging from 0.89-1. CMS analysis showed that general increase in world exports, commodity composition, and market distribution had positive effects, while the competitiveness factor had a negative effect on the growth of Indonesia's rattan product exports for the 2017-2021 period.
Keyword: Revealed Comparative Advantage, Constant Market Share, Competitiveness, Trade  Specialization Index, Rattan Products

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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