Judul: Suatu Studi Tentang Penangkapan Tuna oleh PT perikanan Samodra Besar, Benoa Bali
Abstrak: Sampai saat i n i usaha penangkapan tuna d i perairan i-n donesia masih memberikan kemungkinan yang baik untuk dikembangkan. Dari potensi tuna dan skipjack di perairan Indonesia yang diperkirakan sekitar 207 000 ton, namun baru t+ % yyan dikelola. Satu unit penangkapan rawai tuna terdiri dari kapal, alat penangkapan dan tenaga kerja. Kapal yang digunakan untuk operasi adalah kapal besi berukuran rata-rata 111 GT, 370 FIP dan crew sebanyak 23 orang.
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Judul: Studi Tentang Teknis Operasional Perikanan Rawai Tuna (Tuna Long Line) di PT Perikanan Samodra Besar, Benoa-Bali
Abstrak: Penelitian ini bertujuan untuk mengetahui teknis operasional yang dilakukan pada operasi penangkapan rawai tuna, dalam usaha untuk memproduksi ikan tuna segar (fresh tuna). Penelitian ini dibagi dalam dua tahap yaitu pengumpulan data sekunder berupa data hasil tangkapan, dan pengambilan data di lapang yang dilakukan pada saat mengikuti operasi penangkapan di perairan Samudera Hindia dari tanggal 24 Maret sampai 12 April 1988, dengan menggunakan KM Samodra 19 milik PT Perikanan Samodra Besar, Benoa Bali. Ikan tuna telah mampu memberikan andil dalam ekspor ikan yang merupakan sumber devisa bagi negara Indonesia. Salah satu negara pengimpor tuna adalah negara Jepang, yaitu dalam bentuk ikan tuna segar (fresh tuna) untuk di- konsumsi dalam keadaan mentah. Daya tahan optimal ikan tuna segar adalah 15 hari. Hal ini mempengaruhi lama waktu operasi penangkapan yang dapat dilakukan yaitu maksimum 10 hari dan daerah penangkapannya akan lebih terbatas. PBU Sehari sebelum melakukan operasi penangkapan ikan, semua komponen yang menunjang keberhasilannya harus terlebih dahulu disiapkan. Pengoperasian alat tangkap rawal tuna mencakup dua tahap yaitu penglepasan rawai (setting) dan penarikan rawai (hauling). Penglepasan rawai dilakukan di bagian buritan kapal, sedangkan penarikan rawai dilakukan di bagian haluan kapal. ...
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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