Judul: Optimization of Gold Fish (Carassius auratus) Aquaculture  in Ciseeng Village, Ciseeng District, Bogor Regency
Abstrak: Sektor perikanan merupakan sektor penting dalam pembangunan ekonomi nasional. Perikanan budidaya memiliki produksi dan pertumbuhan lebih besar dibandingkan perikanan tangkap. Budidaya ikan mas koki memiliki peluang yang besar untuk dikembangkan, namun sistem produksi budidaya komoditas tersebut belum optimal. Penelitian ini bertujuan (1) mengidentifikasi faktor-faktor yang memengaruhi produksi ikan mas koki (2) menganalisis tingkat optimal faktor produksi ikan mas koki (3) mengkaji kelayakan finansial usaha budidaya ikan mas koki (4) merumuskan alternatif kebijakan dalam budidaya ikan mas koki. Metode penelitian yang digunakan adalah metode survei. Jenis data yang digunakan adalah data primer dan sekunder. Metode sensus dan purposive sampling digunakan sebagai metode pengambilan contoh. Metode analisis data menggunakan analisis regresi berganda, analisis optimalisasi produksi, cost-benefit analysis, dan Weighted Sum Model. Hasil penelitian menunjukkan bahwa faktor yang berpengaruh nyata adalah benih, pakan, pupuk, dan lama pengalaman. Tingkat penggunaan input optimal ikan mas koki untuk satu siklus budidaya pada rata-rata luas kolam 3.231,7 m2 dengan kedalaman 1 m yaitu benih sebanyak 65.799,69 ekor atau sebesar 526,39 kg, pakan sebanyak 168,41 kg, dan pupuk sebanyak 990,96 kg. Produksi optimal ikan mas koki di Desa Ciseeng jika menggunakan input optimal pada tahun 2020 adalah 35.563,19 ekor atau 142,48 kg. Pengalaman pembudidaya rata-rata 10,7 tahun. Budidaya ikan mas koki pada kondisi aktual layak untuk dilakukan berdasarkan kriteria kelayakan investasi yaitu Net Present Value sebesar Rp 49.897.474, Net B/C sebesar 2,78, Internal Rate of Return sebesar 24%, dan Payback Period sebesar 4 tahun 6 bulan. Prioritas utama alternatif kebijakan dalam mengatasi hambatan budidaya adalah meningkatkan kapasitas kelompok pembudidaya ikan., The fisheries sector plays an important role in national economic development. Aquaculture has higher growth rate production compared to capture fisheries. Gold fish aquaculture has a great opportunity to be developed, however the aquaculture production has not been optimal yet. Based on that problem, the objectives of this research are (1) to identify the factors that affect the production of goldfish aquaculture (2) to analyze the optimal level of goldfish production factors (3) to examine the financial feasibility of goldfish aquaculture (4) to formulate and recommend alternative policies in goldfish aquaculture. The research method used is survey method. The type of data used are primary and secondary data. Census and purposive sampling are used in this research technique sampling. Data analysis methods used are multiple regression analysis, optimization of production, cost-benefit analysis, and Weighted Sum Model. The results of this research showed that factors which significantly affected the production were seeds, feed, fertilizer, and the length of experience. The optimal level used of input for one aquaculture cycle with an average area of pond 3.231,7 m2 and a depth of 1 meter are 65.799,69 fish or 526,39 kg, 168,41 kg of feed, and 990,96 kg of fertilizers. The optimal production of gold fish aquaculture in Ciseeng Village using optimal input in 2020 is calculated by 35.563,19 fish or 142,48 kg. The average experience farmers of fish is 10,7 years. The aquaculture of goldfish in actual condition is feasible based on financial feasibility criteria, respectively Net Present Value of Rp 49.897.474, Net B/C of 2,78, Internal Rate of Return of 24%,
Keyword: cost-benefit analysis, Cobb-Douglas function, aquaculture groups, optimal input, Weighted Sum Model

Judul: Analisis Faktor Faktor Yang Mempengaruhi Produksi dan Pendapatan Usaha Budidaya Ikan Mas Koki di Kelompok Budidaya Tugu Mina Asri, Kabupaten Tulungagung.
Abstrak: Goldfish is one of the potential fisheries products for increasing production to meet demand at Indonesia and other country. However, the production of a goldfish is still volatile at farmers.Tugu Mina Asri Fish Farming is a group that often get credit for rated well in cultivating ornamental fish goldfish. This study uses a Cobb-Douglas function to analyze the factors that the affect production and farmer income of ornamental fish goldfish. This study shows farming income of Rp 109,324,000.00 and R/C ratio of 1.68 so that the cultivation of goldfish is profitable and feasible. While the factors that influence the production is stocking density, feed pellets, and medicine.
Keyword: Tulungagung, Income, Factor Production, Goldfish

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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