Judul: Pengaruh Kuota Ekspor Terhadap Harga Karet Alam Domestik Indonesia
Abstrak: ALFI NURDINA. Pengaruh Kuota Ekspor Terhadap Harga Karet Alam Domestik Indonesia. HARMINI dan AMZUL RIFIN. Agreed Export Tonnage Scheme adalah kebijakan untuk membatasi kuota ekspor karet alam oleh 3 negara yakni Indonesia, Malaysia, dan Thailand. Kebijakan ini bertujuan menaikkan harga karet alam dunia. Kebijakan tersebut diduga juga mempengaruhi harga karet alam bulanan di petani oleh karena itu penelitian ini bertujuan untuk menganalisis pengaruh kebijakan kuota ekpor terhadap harga karet alam domestik Indonesia. Penelitian menggunakan data times series bulanan dari januari 2013 hingga desember 2019. Metode yang digunakan adalah Error Correction Model untuk mengetahui variabel-variabel yang berpengaruh nyata terhadap harga karet alam Indonesia. Variabel total ekspor 3 negara dengan lag -3 berpengaruh negatif dan signifikan baik jangka panjang maupun jangka pendek pada harga karet alam domestik. Sedangkan Dummy kebijakan pembatasan ekspor tidak berpengaruh pada harga karet alam domestik petani. Sehingga dapat disimpulkan kebijakan pembatasan ekspor berpengaruh pada harga karet alam domestik petani yang namun masih butuh perbaikan. Perbaikan tersebut meliputi pengawasan, perancangan kebijakan yang kontinu dan penambahan kerjasama dengan produsen karet alam lain., ALFI NURDINA. The Effect of Export Quotas on Indonesia's Domestic Natural Rubber Prices. HARMINI and AMZUL RIFIN. The Agreed Export Tonnage Scheme is a policy to limit natural rubber export quotas by 3 countries, namely Indonesia, Malaysia and Thailand. This policy aims to increase the price of natural rubber in the world. The policy also affects the monthly natural rubber prices at the farmers. Therefore, this study aims to analyze the effect of export Quotas policy on Indonesia's domestic natural rubber prices. The study uses monthly times series data from January 2013 to December 2019. The method used is the Error Correction Model to determine the variables that have a significant effect on the price of Indonesian natural rubber. The variable total exports of 3 countries with lag -3 has a negative and significant effect both in the long and short term on the domestic natural rubber price. Meanwhile, Dummy's export policy has no effect on domestic natural rubber prices. So can be concluded that the policies has effect of domestik natural rubber price but that policy needs to be improved. These improvements include supervision, continuous policy design and additional collaboration with other natural rubber producers.
Keyword: ECM, karet alam, harga domestik, AETS, natural rubber, domestik price

Judul: The Effect of Expanding the Coverage of International Tripartite Rubber Council (ITRC) on World Rubber Prices
Abstrak: Salah satu hasil perkebunan yang menjadi komoditas utama dan diekspor oleh negara Indonesia adalah karet. Namun, karet memiliki masalah yang krusial yakni fluktuasi harga karet dunia. Oleh karena itu, dibentuk sebuah forum kerjasama yang dikenal sebagai International Tripartite Rubber Council (ITRC) untuk menstabilkan harga karet. Dalam melakukan kebijakan ITRC terlihat bahwa negara anggota tidak memberikan dampak yang signifikan terhadap harga karet dunia. Penelitian ini bertujuan untuk menganalisis penambahan cakupan negara anggota ITRC dalam memperbaiki harga karet dunia dengan menggunakan ARDL dan ECM dengan periode 2013-2019. Selain itu, penelitian ini juga melihat dinamika ekspor dan harga dari negara–negara tambahan maupun negara ITRC dengan menggunakan metode deskriptif. Hasil penelitian menunjukkan bahwa penambahan negara lainnya tidak memberikan dampak yang signifikan terhadap perbaikan harga karet dunia. Hal ini dibuktikan dengan penggunaan dua model dalam memastikan bahwa hasil yang didapat benar adanya. Dan hasil yang ditunjukkan pada metode ARDL sejalan dengan hasil dari metode ECM yang berarti bahwa kebijakan pembatasan ekspor sudah tidak efektif dalam memperbaiki harga karet dunia, Rubber is one of the major agricultural commodities produced and exported by Indonesia. However, rubber faces a crucial issue of fluctuating world prices. Therefore, an international cooperation forum known as the International Tripartite Rubber Council (ITRC) was established to stabilize rubber prices. However, the policy measures implemented by the ITRC member countries do not seem to have a significant impact on world rubber prices. This research aims to analyze the impact of expanding the coverage of ITRC member countries in improving world rubber prices using the ARDL and ECM models for the period of 2013-2019. Additionally, this study examines the dynamics of exports and prices among the additional countries and the existing ITRC member countries using descriptive methods. The research findings indicate that the addition of countries does not have a significant impact on improving world rubber prices. This is supported by the use of two models to ensure the validity of the results. Both the ARDL and ECM models show consistent results, indicating that export restriction policies are no longer effective in improving world rubber prices.
Keyword: World Rubber Prices, Export Restrictions, ARDL, ECM

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.
Keyword: