Judul: Profitabilitas Usaha Pengolahan serta Nilai Tambah Produk Ubi Jalar pada Kelompok Tani Hurip di Desa Cikarawang, Bogor
Abstrak: Sweet potato has potentialy to be developed in an effort to diversify food. Sweet potato production in Indonesia is high, one of production centre in West Java. Sweet potato as food has not been used optimally. Post-harvest processing can increase the shelf life as well as the added value of sweet potatoes. Farmers Hurip (KTH) is a producer of sweet potato flour in the Bogor area. The aim of this research is to analyze the profitability and value added processing sweet potato to flour at KTH. The research was conducted at KTH is located in the village of Cikarawang, Dramaga District, Bogor Regency. This research was conducted from February 2013 to April 2013. The results showed that the sweet potato process business run by KTH has not been able to turn a profit. That is because quite a high variable costs, especially in raw material costs. Current efforts KTH sweet potato flour has not been able to break even, which means that the company has not been able to cover the cost factor and still experiencing losses. Value added generated by the use of dry shredded material is greater than the fresh sweet potatoes.
Keyword: value-added, sweet potato flour, profitability, cost analysis

Judul: Analisis Kelayakan Pengembangan Usaha Penggilingan Tepung Ubi Jalar pada KWT Berkah Sari Desa Purwasari, Kecamatan Dramaga, Kabupaten Bogor
Abstrak: Berkah Sari as a woman farmer group has been processing sweet potatoes into sweet potatoes flour. It is located in Purwasari Village, Dramaga Subdistrict, Bogor District. This study aims to (1) analyze the feasibility of nonfinancial aspects such as market; technical; management and legal; economic and social; and enviromental aspects of sweet potatoes flour business on the actual condition and adding a new investment of milling machine (development condition); (2) analyze the feasibility of financial aspects such as Net Present Value (NPV), Net Benefit Cost Ratio (Net B/C Ratio), Internal Rate of Return v (IRR), and Payback Period (PP) on the actual condition and adding a new investment of milling machine (development condition); and (3) analyze the switching value of increasing input price and decreasing output price. Based on non-financial analysis, almost all aspects were feasible, except for production process in technical aspect and legal aspect. Based on financial analysis, the actual condition was not feasible, except for payback period criteria. In terms of development condition, it was feasible where the NPV was IDR104 440 708.02, net B/C 4.42, IRR 63 percent, and Payback Period 1.14. The discount rate was 5.75 percent. Switching value analysis showed that the increasing purchasing price of fresh sweet potatoes by 69.32 percent and the decreasing price of sweet potatoe flour by 17.94 percent were still feasible. The Incremental Net Benefit from actual to development conditions was IDR107 768 620.67, implying that the new invesment of milling machine would give benefit to Berkah Sari woman farmer group
Keyword: PP, IRR, Net B/C, NPV, Incremental Net Benefit

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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