Judul: Study of mechanical rice transplanting performance in Sukamandi Village, Subang District, West Java
Abstrak: Penanaman bibit padi di lahan sawah dapat dilakukan secara manual dan mekanis menggunakan walking type rice transplanter. Tujuan dari penelitian ini adalah menganalisis unjuk kerja penanaman bibit padi secara manual dan mekanis menggunakan walking type rice transplanter meliputi keseragaman penancapan bibit, kapasitas penanaman, dan biaya penanaman. Hasil penelitian menunjukkan bahwa keseragaman penancapan bibit rata-rata, kapasitas penanaman rata-rata, dan biaya penanaman rata-rata pada penanaman secara manual dan secara mekanis berturut-turut sebesar 75.83% dan 61.41%, 0.009 ha/jam/orang dan 0.143 ha/jam, Rp 666 667/ha dan Rp 476 223/ha., Rice transplanting on rice wet land could be done manually or mechanically utilizing a walking type rice transplanter. The objective of this research was to analyze rice transplanting performances, that are uniformity of rice transplanting, transplanting capacity, and transplanting cost. Result of this research showed that uniformity of rice transplanting, transplanting capacity, and transplanting cost manually and mechanically were 75.83% and 61.41%, 0.009 ha/hour/person and 0.143 ha/hour, and Rp 666 667/ha and Rp 476 223/ha in average respectively.
Keyword: penanaman bibit, manual, walking type rice transplanter, keseragaman penancapan bibit, kapasitas penanaman, dan biaya penanaman.

Judul: Performance and Economics Test of Rice Combine Harvester in Innovation Village, Subang, West Java
Abstrak: Penanganan padi siap panen merupakan salah satu kunci untuk meningkatkan perolehan hasil dari kemungkinan pengurangan nilai susut. Proses pemanenan padi di Indonesia banyak dilakukan secara manual dengan cara dipotong dengan menggunakan sabit dan perontokan dengan cara digebot yang berdampak pada susut yang tinggi. Penggunaan alat dalam memanen padi seperti combine harvester sudah banyak ditemukan karena memiliki susut yang relatif kecil, namun kalah bersaing karena stigma akan biaya operasional yang terlalu mahal yang akan berdampak pada pendapatan petani. Penelitian ini bertujuan untuk menganalisis aspek kinerja dan ekonomi dari penggunaan combine harvester sebagai alat bantu proses pemanenan padi; membandingkan hasil analisis pemanenan padi menggunakan combine harvester dengan cara manual; serta menganalisis kelayakan usaha mesin combine harvester di Kampung Inovasi Subang, Desa Kiarasari, Kecamatan Compreng, Kabupaten Subang. Penelitian dilakukan dengan mengamati beberapa variabel dalam pemanenan secara manual dan pemanenan dengan menggunakan combine harvester. Variabel yang diamati berupa variabel kinerja berupa kapasitas lapang efektif (KLE) dan kapasitas lapang teoritis (KLT) pemanenan secara mekanis (ha/jam), KLE dan KLT pemanenan secara manual, efisiensi lapang pemanenan (ELP) (%), susut panen (%), dan variabel ekonomi berupa biaya pokok pemanenan (Rp/ha). KLE pemotongan dengan sabit memiliki nilai rata-rata sebesar 0,018 ha/jam/orang dan efisiensi pemotongan sebesar 77% sedangkan KLE menggunakan combine harvester sebesar 0,5047 ha/jam dan efisiensi pemotongannya sebesar 82,28%. Susut hasil pemotongan padi menggunakan sabit sebesar 7,50% dengan susut perontokannya sebesar 0,086% sehingga total susut sebesar 7,59%, sementara susut total pemanenan menggunakan combine harvester sebesar 0,067%. Biaya total pemanenan dengan metode manual (sabit + power thresher) sebesar Rp 3.531.577,00 /ha, sedangkan biaya total yang dengan combine harvester sebesar Rp 1.857.143,00 /ha., Handling ready-to-harvest rice is one of the keys to increasing yield gain from possible reduction in value of losses. The process of harvesting rice in Indonesia is mostly done manually by cut using a sickle and threshing with digebot which has an impact on high shrinkage. The use of tools in harvesting rice such as a combine harvester has been widely found because it has a relatively small shrinkage, but it is less competitive because of the stigma of operational costs that are too expensive which will have an impact on farmers' income. This study aims to analyse the performance and economic aspects of using a combine harvester as a tool for rice harvesting; compare the results of rice harvesting analysis using a combine harvester with the manual method; and analyse the business feasibility of combine harvester machines in Subang Kampung Inovasi, Kiarasari Village, Compreng Subdistrict, Subang Regency. The research was conducted by observing several variables in manual harvesting and harvesting using a combine harvester. The variables observed were performance variables in the form of effective field capacity (KLE) and theoretical field capacity (KLT) of mechanical harvesting (ha/h), KLE and KLT of manual harvesting, harvesting field efficiency (ELP) (%), harvest shrinkage (%), and economic variables in the form of cost of harvesting (Rp/ha). The ELP of cutting with sickle has an average value of 0,018 ha/hour/person and cutting efficiency of 77% while the ELP using combine harvester is 0,5047 ha/hour and the cutting efficiency is 82,28%. The shrinkage of rice
Keyword: biaya operasional, combine harvester, panen padi, produktivitas, susut, operational cost, productivity, rice harvesting, shrinkage

Judul: The Exploration of Discrete Logarithm over Finite Field GF(3m)
Abstrak: The security of many public~key algorithms is based on the problem of finding discrete logarithms. The generalized discrete logarithm problem is the following: given a finite cyclic group G of order n, a generator a of G, and an element fl E G, find the integer x, 0 ~ x ~ n - 1, such that 0: = fl. Algorithm for discrete logarithm problem focused on Menezes et al. (1997) that consist of exhaustive search algorithm, the baby-step giant-step algorithm, Pollard's rho algorithm, Pohlig-Hellman algorithm, and index-calculus algorithm. These algorithms are explorated to be used in discrete logarithm problem over finite field GF(3m ). The exploration also produces some algorithms, i.e. naif negative algorithm, baby-step mother-step algorithm, baby-step mother free-step algorithm, and baby-step free-step algorithm. All algorithms implemented using Maple 11. The Pohlig-Hellman and baby-step giant-step algorithms are efficient enough to be used in discrete logarithm problem over finite field GF(3m ) for m < 20.
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