Judul: Struktur komunitas zooplankton di perairan pesisir sekitar muara sungai Cimanuk Kabupaten Indramayu, Jawa Barat
Abstrak: Muara Sungai Cimanuk terdapat di Desa Brondong, Kabupaten Indramayu, Jawa Barat. Bahan organik dan partikel lain hasil samping aktivitas manusia melalui aliran air sungai terbawa ke daerah ini, sehingga mempunyai tingkat kekeruhan yang sangat tinggi. Di sekitar muara tersebut banyak terdapat areal pertambakan. Tujuan penelitian ini untuk mengevaluasi struktur komunitas zooplankton yang meliputi kelimpahan, komposisi, keragaman, keseragaman dan dominasi sehubungan dengan kondisi parameter fisika-kimia perairan pesisir sekitar Muara Sungai Cimanuk. Hasil yang diperoleh juga diharapkan sebagai dasar informasi bagi pengelolaan pembangunan wilayah pesisir di daerah ini secara berkelanjutan. Pengamatan dilakukan di 7 stasiun berdasarkan tingkat kekeruhan dan aliran air yang mempengaruhi. Parameter fisika-kimia yang diukur meliputi kedalaman, kecerahan, TSS, suhu, salinitas, pH, Oksigen terlarut, BOD5 dan TOM. Kecerahan, kekeruhan dan TSS lebih berpengaruh terhadap struktur komunitas zooplankton yaitu menyebabkan rendahnya keragaman zooplankton. Parameter lain masih sesuai dengan kehidupan zooplankton. ...
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Judul: Struktur Komunitas Makrozoobenthos Di Perairan Muara Sungai Cimanuk Kabupaten Indramayu Jawa Barat
Abstrak: Sungai Cimanuk telah banyak digunakan untuk aktivitas manusia/penduduk sekitarnya untuk kebutuhan sehari-hari terutama untuk MCK, transportasi perikanan, dan lain-lain. Hal ini akan mempengaruhi kondisi perairan dan sekaligus akan menurunkan kualitas perairan itu sendiri. Adapun tujuan penelitian ini adalah ingin mengetahui struktur komunitas makrozoobenthos serta interaksinya dengan beberapa parameter lainnya dan melihat perubahan secara temporal dan spasial.
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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