Judul: Analisis Usahatani dan Tataniaga Jamur Tiram Putih (Studi Kasus: Desa Kertawangi, Kecamatan cisarua, Kabupaten Bandung).
Abstrak: Permintaan konsumsi pangan yang berasal dari bahan baku (komoditas) organik meningkat dengan cepat. Tanaman organik dibudidayakan dengan meminimalkan penggunaan pestisida kimiawi, maka tanaman ini relatif lebih aman. Harga komoditas tanaman organik yang cukup maha1, menyebabkan tidak semua kalangan masyarakat dapat mengkonsumsinya Namun tidak semua komoditas yang aman dari penggunaan pestisida kimiawi memiliki barga beli yang mahal Salah satunya Yaltu jamur tiram (pleurotus ostreoatus). Desa Kertawangi, Kecamatan Cisarua, Bandung merupakan salah satu sentra penanaman jamur tiram.
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Judul: Analisis Usahatani Jamur Tiram Putih (Kasus Komunitas Petani Jamur Ikhlas, Desa Cibening, Kecamatan Pamijahan,Kabupaten Bogor)
Abstrak: Meningkatnya permintaan jamur tiram putih sekitar 20 sampai dengan 25 persen per tahun (Masyarakat Agribisnis Jamur Indonesia, 2008) belum dapat dipenuhi oleh petani. Prospek pasar yang tinggi tersebut akan menambah semangat petani termasuk didalamnya adalah para petani yang tergabung dalam Kelompok Petani Jamur Ikhlas (KPJI) untuk terus melakukan usaha budidaya jamur tiram putih. Namun demikian produktivitas yang dihasilkan oleh petani di Komunitas Petani Jamur Ikhlas ini belum maksimal serta keterbatasan modal. Tujuan penelitian ini adalah (1) mendeskripsikan usahatani jamur tiram putih di Komunitas Petani Jamur Ikhlas, (2) Menganalisis biaya dan pendapatan usahatani jamur tiram putih di Komunitas Petani Jamur Ikhlas dan (3) Menganalisis efisiensi usahatani jamur tiram putih di Komunitas Petani Jamur Ikhlas. Penelitian dilaksanakan di Komunitas Petani Jamur Ikhlas (meliputi dua kelompok petani yang terdiri dari enam orang petani jamur tiram putih) di Desa Cibening, Kecamatan Pamijahan, Kabupaten Bogor. Waktu penelitian di lapang dilaksanakan pada bulan Juli sampai dengan bulan September tahun 2009. Penelitian ini menggunakan analisis usahatani yang terdiri dari biaya dan pendapatan serta efisiensi. Diketahui bahwa aktivitas usahatani jamur tiram putih kelompok petani meliputi pemilihan lokasi, pembuatan kumbung, penyiraman, pengendalian hama pengaturan suhu ruangan dan panen, sedangkan pihak Komunitas Petani Jamur Ikhlas (KPJI) sebagai pihak manajemen yang membeli baglog untuk dirawat oleh kelompok petani dimana hasil akhir produk adalah jamur tiram putih segar dijual ke pedagang.
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Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm