Judul: Analisis pendapatan petani dan marjin pemasaran beras organik (Studi kasus: Kecamatan Cikalong, Kabupaten Cianjur, Jawa Barat)
Abstrak: Sistem pertanian organik merupakan salah satu alternatif untuk mengurangi dampak negatif yang telah ditimbulkan oleh revolusi hijau dan sebagai alternatif untuk memeperkecil biaya dalam berusahatani. Pertanian organik telah banyak dikembangkan dibeberapa Pulau Jawa, salah satunya di Jawa Barat. Kecamatan Cikalong dipilihnya sebagai tempat penelitian pertanian organik karena di daerah tersebut telah menerapkan dan mengembangkan sistem pertanian organik. Penelitian ini bertujuan untuk : (1) menganalisa tingkat pendapatan petani organik dan petani an-organik, (2) menganalisa faktor-faktor yang memepengaruhi tingkat pendapatan petani organik dan petani an-organik, (3) menganalisa saluran pemasaran beras organik mulai dari tingkat produsen sampai tingkat konsumen, dan (4) menganalisa marjin pemasaran komoditi beras organik.
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Judul: Analisis pendapatan usahatani dan pemasaran wortel dengan budidaya organik (studi kasus Desa Citeko, Kecamatan Cisarua, Kabupaten Bogor, Jawa Barat)
Abstrak: Revolusi hijau merupakan perubahan pola budidaya tanaman berdasarkan efisiensi. Namun, diduga produk makanan pertanian yang menerapkan konsep revolusi hijau menyebabkan maraknya penyakit kanker di negara-negara maju. Dari sinilah muncul gagasan untuk kembali bercocok tanam dengan cara tradisional dan hanya menggunakan bahan-bahan organik. Sistem pertanian berkelanjutan adalah sistem pertanian yang kembali ke alam (back to nature), yakni sistem pertanian yang tidak merusak, tidak mengubah, serasi, selaras, dan seimbang dengan lingkungan, atau pertanian yang patuh dan tunduk pada kaidah-kaidah alamiah. Salah satu model sistem pertanian yang berkelanjutan adalah sistem pertanian organik. Sistem pertanian organik itu sendiri merupakan salah satu alternatif solusi atas kegagalan sistem pertanian industrial. Komoditas hortikultura khususnya wortel merupakan jenis komoditas yangtepat untuk dikembangkan bagi pasar produk organik.
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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