Judul: Kondisi hidrodinamika dan kualitas fisik-kimia air pada periode musim timur di Perairan Selat Sele, Sorong, Irian Jaya
Abstrak: Penelitian ini dilakukan di perairan Selat Sele, Kabupaten Sorong, Irian Penelitian bertujuan untuk mengetahui kondisi dinamika massa air Jaya. permukaan pada musim timur selain juga parameter fisik-kimiawi kualitas air (suhu, salinitas, pH, kecerahan, kekeruhan, oksigen terlarut, BOD, COD dan kandungan hidrokarbon). Penelitian dinamika massa air bermanfaat untuk mengetahui gerak massa air pengaruh pasang surut di perairan Selat Sele. Data yang digunakan terdiri atas data primer dan data sekunder. Data primer terdiri dari data hasil pengukuran parameter fisik-kimiawi kualitas air, baik yang dilakukan secara insitu maupun exsitu. Data sekunder berupa data ramalan pasang surut untuk daerah Sorong (tahun 1996) yang diperoleh dari kantor DISHIDROS-TNI Angkatan Laut, Jakarta. Alat yang digunakan terdiri dari Current meter, Echosounder, Portable GPS, Thermometer, Secchi disc, Turbidity meter, tabung berskala, Salinometer, pH meter, DO meter, alat titrasi, AAS-infra red. Bahan yang digunakan adalah bahan-bahan kimia untuk analisis kimia, bahan pengawet dan contoh air. Pola arus di perairan Selat Sele saat pengamatan mempunyai kisaran kecepatan antara 0,08 0,90 meter/detik. Berdasarkan pengamatan mengenai pola pasang surut diketahui bahwa arus yang terjadi pada saat surut mengalir ke arah utara dengan kecepatan berkisar antara 0,34 0,9 meter/detik, sementara pada saat pasang arus mengalir ke arah selatan dengan kecepatan berkisar antara 0,08 0,58 meter/detik. Pasang surut perairan Selat Sele bersifat campuran dominansi harian ganda. Suhu perairan Selat Sele berkisar antara 3033,8 °C. Nilai tersebut di luar kisaran suhu alami perairan laut, yaitu antara 2831 °C (Nontji, 1987). Suhu di perairan muara Sungai Wakanway tercatat sebesar 33,8 °C, yang diketahui karena adanya pengaruh buangan limbah air terproduksi. Nilai salinitas perairan Selat…dst
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Judul: Kondisi oseanografi Perairan Selat Makassar pada Juli 1991 (Musim Timur)
Abstrak: Penelitian ini bertujuan untuk mempelajari sebaran menegak dari suhu, salinitas, oksigen terlarut, fosfat, nitrat dan silikat pada Musim Timur. Selain itu juga dipelajari tentang adanya suplai massa air dari Samudera Pasifik ke Selat Makassar dan Upwelling. Data yang digunakan dalam penelitian ini adalah data sekunder yang diperoleh dari Bank Data P30-LIPI, Ancol Timur, Jakarta. Data tersebut adalah hasil ekspedisi Kapal Penelitian Baruna Jaya I pada bulan Juli 1991.
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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