Judul: Keragaman makrobentos sebagai indikator kualitas sungai babura
Abstrak: Tujuan penelitian ini untuk mengetahui perubahan kualitas sungai Babura dari mulai hulu sampai ke hilir, berdasarkan keragaman hewan makrobentos akibat pengaruh faktor fisik dan faktor kimia perairan. Pengambilan sampel sebanyak tiga kali di empat lokasi. Adapun lokasi pengambilan sampel sebagai berikut: Lokasi satu daeraah hulu sebagai kontrol karena diperkirakan belum mengalami pencemaran, masih dalam kawasan hutan. Badan air di lokasi dua menerima limbah pertanian karena daerah tersebut merupakan kawasan pertanian, lokasinya di Tebing Ganjang Namurambe. Dari Namurambe sampai Simpang Kuala, aliran sungai Babura melintasi daerah jalur hijau dani pemukiman sehingga badan air menerima limbah pemukiman/domestik. Pengambilan sampel tiga di jalan Simpang Pos, Kwala Bekala Simpang Kuala. Selanjutnya aliran sungai Babura melintasi pemukiman padat dan 1 (satu) industri es balok. Sebelum pertemuan DAS (Daerah Aliran Sungai) Babura dengan DAS Deli ditentukan lokasi empat pengambilan sampel di daerah Petisah Medan.
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Judul: Studi tentang Keadaan Sedimen Dasar dan Makrobentos di Sekitar Delta Muara Jaya, Sungai Citarum, Teluk Jakarta
Abstrak: Salah satu dampak dari kegiatan industri ialah makin banyaknya sisa produksi atau limbah yang harus dibuang dan akhirnya dapat menurunkan kualitas ligkungan. yang lebih merasakan dampak tersebut ialah perairan sungai, karena umumnya industri-industri sungai untuk membuang limbah. Daerah muara memanfaatkan Daerah Bekasi dipersiapkan sebagai kawasan industri. Sebagai konsekuensinya, jumlah limbah dan segala macam sisa produksi bertambah banyak, sehingga diperkirakan Sungai Citarum dan sungai-sungai lain yang berada di sekitarnya akan mengalami tekanan ekologis yang lebih berat. Penelitian ini bertujuan untuk mengetahui kualitas perairan, kondisi sedimen dasar dan komunitas makrobentos di sekitar delta Muara Jaya sungai Citarum, Teluk Jakarta. Penelitian dilakukan selama tiga kali periode pengamatan, yaitu 15 Februari, 5 April dan 8 Nopember 1990. Lokasi penelitian termasuk ke dalam wilayah Kecamatan Muara Gembong, Kabupaten Bekasi, Propinsi Jawa Barat. Parameter yang diukur terdiri dari parameter fisik-kimia air (kejelukkan, suhu, salinitas, kecerahan, arus, DO, PH, BOD5 dan COD), kemudian fraksi sedimen, redokspotensial, kandungan logam berat (Hg dan Cd) serta kepadatan dan biomas makrobentos. ...
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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