Judul: Factors Affecting Pepper Production in Indonesia
Abstrak: Lada sebagai komoditas unggulan sub-sektor perkebunan Indonesia, dihadapi oleh rendahnya produktivitas lada yang disebabkan karena perkembangan produksi lada secara nasional masih belum optimal dan mengalami penurunan. Dari segi usahatani lada, petani belum sepenuhnya memperhatikan pentingnya penggunaan sarana produksi terhadap hasil produksi. Dampak yang ditimbullkan adalah penurunan kuantitas hasil produksi lada yang dapat merugikan petani. Tujuan dari penelitian ini adalah untuk mengetahui keragaan usahatani lada di Indonesia dan menganalisis faktor-faktor yang memengaruhi produksi lada di Indonesia. Pada penelitian ini digunakan data Survei Rumah Tangga Perkebunan Tahun 2014 yang bersumber dari BPS. Metode yang digunakan adalah analisis deskriptif dan analisis regresi linier berganda menggunakan fungsi produksi cobbdouglas. Keragaan usahatani lada di Indonesia dalam satu tahun produksi dapat digambarkan dengan hasil produksi sebesar 0,66kg/pohon, kepemilikan jumlah pohon sebanyak 1.113, penggunaan tenaga kerja sebanyak 159 HOK, pupuk NPK sebanyak 122kg, pupuk urea sebanyak 154kg, pupuk organic sebanyak 82kg, pestisida sebanyak 11,4L, bibit tidak bersertifikat, dan pola tanam monokultur. Faktor-faktor yang berpengaruh positif dan signifikan terhadap produksi lada yaitu jumlah pohon, usia tanaman, tenaga kerja, pupuk NPK, pestisida, dan dummy pola tanam., Pepper as the leading commodity of the Indonesian plantation sub-sector, is faced by the low productivity of pepper caused by the development of pepper production nationwide is still not optimal and has decreased. In terms of pepper farming, farmers have not fully considered the importance of using production facilities to the yields. The resulting impact is a decrease in the quantity of pepper production that can harm farmers. The purpose of this study is to identify the business practices of pepper farming in Indonesia and analyze the factors affecting pepper production in Indonesia. The source data used in this study were from the 2014 Plantation Household Survey by BPS. The methods used are descriptive analysis and multiple linear regression analysis using the cobb-douglas production function. The production of pepper business in Indonesia can be described by 0.66 kg/tree production, ownership of 1,113 trees, labor use of 159 HOK, NPK fertilizer of 122 kg, urea fertilizer of 154 kg, organic fertilizer of 82 kg, pesticide of 11.4L, uncertified seeds, and monoculture cropping system. Factors that have a positive and significant effect on pepper production are the number of trees, age of plants, labor, NPK fertilizer, pesticides, and dummy cropping system.
Keyword: Cobb-douglas, Production factors, Pepper

Judul: Analysis of Competitiveness, Potential,  and Factors Affecting Indonesian Whole Pepper Exports to Main Destination  Countries
Abstrak: Salah satu komoditas unggulan ekspor perkebunan yang menjadi sumber pendapatan negara yang bernilai tinggi adalah lada utuh. Penelitian ini bertujuan untuk menganalisis daya saing dan pasar potensial untuk ekspor lada utuh yang bisa dikembangkan, serta mengetahui faktor-faktor yang memengaruhi ekspor komoditas lada utuh. Periode yang digunakan pada penelitian ini yaitu 2010-2020 dengan menggunakan metode RCA, EPD, X-Model, dan regresi data panel. Hasil penelitian menunjukkan bahwa lada utuh memiliki keunggulan komparatif yang kuat di seluruh negara tujuan ekspor yang diteliti, sementara pangsa pasar lada utuh Indonesia sebagian besar menempati posisi falling star dengan pengembangan pasar potensial. Hasil analisis dengan regresi data panel menunjukkan bahwa PDB per kapita negara tujuan, harga ekspor, nilai tukar riil, jarak ekonomi, dummy Covid-19, dan dummy kebijakan TBT berpengaruh signfikan terhadap volume ekspor lada utuh Indonesia sedangkan variabel dummy kebijakan SPS tidak berpengaruh signfikan terhadap ekspor lada utuh Indonesia ke negara tujuan utama., One of the leading export commodities of plantations which is a source of high-value state income is whole pepper. This study aims to analyze the competitiveness and potential market for whole pepper exports that can be developed, as well as to determine the factors that affect the export of whole pepper commodities. The period used in this study is 2010-2020 using the RCA, EPD, X-Model, and panel data regression methods. The results showed that whole pepper has a strong comparative advantage in all export destination countries studied, while the market share of Indonesian whole pepper mostly occupies a falling star position with potential market development. The results of the analysis with panel data regression showed that the GDP per capita of the destination country, export prices, real exchange rates, economic distance, the Covid-19 dummy, and the TBT policy dummy had a significant effect on the volume of Indonesian whole pepper exports, while the SPS policy dummy variable had no significant effect on Indonesian whole pepper exports to main destination countries.
Keyword: panel data, EPD, RCA, whole pepper, X-Model

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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