Judul: Karakterisasi dan uji aktivitas Psudomonas sp. dan flavobacterium sp. pereduksi merkuri asal Pongkor dan Kalimantan Tengah
Abstrak: Perindustrian, pertanian, pertambangan dan keseahatan banyak menggunakan merkuri, logam berat neracun, yang merupakan penyebab lingkungan tercemar merkuri. Bioremediasi dengan menggunakan mikroba merupakan suatu teknik pembersihan lingkungan tercemar merkuri yang lebih efektif dan efisien. Penelitian ini bertujuan unutk mengisolasi bakteri pereduksi merkuri, mengkarakterisasi dan mengidentifikasi serta mengetahui kemampuan aktivitas bakteri tersebut dalam mereduksi merkuri. Penelitian dilaksanakandi Laboratorium Mikrobiologi dan Bioteknologi Lingkungan Pusat Penelitian Lingkungan Hidup Institut Pertanian Bogor sejajk bulan November 2000 sampai dengan September 2001.
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Judul: Uji aktivitas merkuri reduktase bakteri dari ekosistem air  hitam Kalimantan Tengah
Abstrak: Penelitian ini dilakukan dengan tujuan untuk mengisolasi bakteri pereduksi merkuri dari Ekosistem Air Hitam (EAH) Kalimantan Tengah serta melakukan uji aktivitas merkuri reduktase dan identifikasi terhadap isolat terpilih. Isolasi bakteri pereduksi merkuri dilakukan pada media agar LB yang mengandung HgC12 20 pg/ml. Isolat yang diperoleh diseleksi lebih lanjut dengan menumbuhkan pada media agar LB yang mengandung HgC12 lebih tinggi yaitu: 50, 100, 200, 300, 400, 500 dan 1000 pglml. Sebanyak 7 isolat dapat tumbuh pada konsentrasi HgC12 1000 pg/ml yaitu ICBB 2798, ICBB 2799, ICBB 2810, ICBB 2812, ICBB 2813, ICBB 2820 dan ICBB 2847.
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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