Judul: Analysis of Competitiveness and Factors Influencing Indonesian Sawn Timber Export
Abstrak: Indonesia dikenal sebagai negara produksi hasil hutan di dunia. Penelitian ini bertujuan menganalisis daya saing dan faktor-faktor yang memengaruhi ekspor kayu gergajian Indonesia. Metode penelitian untuk menganalisis daya saing adalah RCA, EPD, dan X-Model Potensial Export. Metode untuk menganalisis faktor-faktor yang memengaruhi ekspor kayu gergajian Indonesia adalah metode regresi data panel dengan time series 2013-2021 serta cross section enam negara tujuan ekspor. Hasil analisis RCA menunjukkan bahwa Indonesia memiliki daya saing komparatif di negara tujuan ekspor. Hasil EPD menunjukkan posisi pasar falling star di Korea Selatan, India dan Jepang sedangkan posisi rising star China, Bangladesh, dan Vietnam. Hasil X-Model menunjukkan komoditas kayu gergagjian memiliki potensi ekspansi pasar yang potensial di China, dan Vietnam sedangkan kurang potensial Jepang, India dan Korea Selatan serta posisi optimis ditempati Bangladesh. Hasil analisis regresi data panel menunjukkan GDP riil negara tujuan berpengaruh positif terhadap volume ekspor kayu gergajian Indonesia. Sedangkan nilai tukar, harga ekspor, jarak ekonomi dan populasi berpengaruh negatif terhadap volume ekspor kayu gergajian Indonesia., Indonesia is know as the largest forest product producing country in the world. This study aims to analyze competitiveness and the factors that influence Indonesia exports of sawn timber. Research methods to analyze competitiveness are RCA, EPD, and X-Model Potential Export the method for analyzing the factors influencing Indonesian sawn timber export is the panel data regression method with the 2013-2021 time series and cross sections of six export destination countries. The result of the RCA analysis show that Indonesia has comparative competitiveness in export destination country. The EPD result show the market positions of falling stars in South Korea and Japan while the positions of rising stars are China, Bangladesh, Vietnam and India. The result of the X-Model show that the sawn timber commodity has potential for market expansion in China, Vietnam, and India, while Japan and South Korea have less potential and Bangladesh occupy an optimistic position. The result of the panel data regression analysis show that the real GDP of the destination country has a positive effect on the export volume of Indonesia sawn timber. Meanwhile the exchange rate, export price, economic distance and population have a negative effect on the export volume of Indonesia sawn timber.
Keyword: EPD, Regresi Data Panel, RCA, X-Model, Kayu Gergajian

Judul: Comparative Competitiveness of Indonesian and Chinese Plywood Exports in the ASEAN+3 Market and its Influencing Factors
Abstrak: Indonesia dan China merupakan pengekspor utama kayu lapis dunia.ASEAN+3 menjadi salah satu kawasan importir kayu lapis dengan pangsa 20% sehingga wilayah ini menjadi salah satu tujuan ekspor kayu lapis. Hal ini menimbulkan persaingan antara kedua negara dalam perdagangan kayu lapis khususnya wilayah ASEAN+3. Penelitian ini bertujuan untuk menganalisis perbandingan daya saing Indonesia dan China di pasar ASEAN+3 serta mengetahui faktor yang memengaruhinya. Penelitian ini menggunakan sepuluh negara wilayah ASEAN+3 pada periode 2015-2022. Metode yang digunakan RCA, EPD, X-Model dan analisis regresi. Hasil perhitungan menunjukkan nilai RCA Indonesia dan China berdaya saing kuat di sepuluh negara Kawasan ASEAN+3. Hasil EPD menunjukkan posisi rising star untuk kayu lapis Indonesia di tujuh negara dan di China posisi rising star hanya di empat negara. Metode X-Model menunjukkan Brunei Darussalam, Jepang, Korea Selatan, Thailand dan Vietnam berpotensi menjadi pasar yang optimis untuk pengembangan ekspor kayu lapis Indonesia, sedangkan ekspor kayu lapis China memiliki potensi yang sama di Malaysia, Myanmar dan Vietnam. Hasil ini menunjukkan daya saing kayu lapis Indonesia lebih baik dibandingkan China. Hasil analisis regresi faktor yang memengaruhi volume ekspor kayu lapis Indonesia yakni GDP riil, populasi, harga ekspor, nilai RCA, dan kurs riil negara importir., Indonesia and China are the world's main exporters of plywood. ASEAN+3 is one of the plywood importing regions with a share of 20% so that this region is one of the plywood export destinations. This has led to competition between the two countries in the plywood trade, especially in the ASEAN+3 region. This study aims to analyse the comparative competitiveness of Indonesia and China in the ASEAN+3 market and determine the factors that influence it. This study uses ten countries in the ASEAN+3 region in the period 2015-2022. The methods used are RCA, EPD, X-Model and regression analysis. The calculation results show the RCA values of Indonesia and China are strongly competitive in the ten countries of the ASEAN+3 Region. The EPD results show a rising star position for Indonesian plywood in seven countries and in China a rising star position in only four countries. The X-Model method shows Brunei Darussalam, Japan, South Korea, Thailand and Vietnam are potentially optimistic markets for the development of Indonesian plywood exports, while Chinese plywood exports have the same potential in Malaysia, Myanmar and Vietnam. This result shows that the competitiveness of Indonesian plywood is better than that of China. The results of the regression analysis of factors affecting the volume of Indonesian plywood exports are real GDP, population, export prices, RCA values, and real exchange rates of importing countries.
Keyword: analisis regresi, daya saing, epd, kayu lapis, 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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