Judul: Studi Kandungan Fosfor di Air dan Sedimen yang Dipegaruhi Aktivitas Jaring Apung di Waduk Cirata, Jawa Barat
Abstrak: Penelitian ini bertujuan untuk mengetahui dan mengkaji kandungan fosfor di air dan sedimen khususnya di wilayah yang dipengaruhi aktivitas karamba kering apung di Waduk Cirata, Jawa Barat dengan pengambilan contoh satu kali setiap bulan mulai Bulan Juli-September 2006. Kondisi lingkungan di empat stasiun pengamatan meliputi kedalaman yang mengalami penurunan setiap bulan dan waktu pengamatan masuk pada periode musim kemarau.
Keyword: 

Judul: Kandungan P dan H2S pada keramba jaring apung di Waduk Cirata, Jawa Barat
Abstrak: Penelitian ini bertujuan untuk mengetahui kandungan P (Total Fosfor dan Ortofosfat) serta H₂S (Hidrogen Sulfida) sebagai limbah hasil buangan keramba jaring apung pada perairan eutrof, Waduk Cirata. Penelitian dilaksanakan bulan Mei sampai Juli 2005 di KJA Babakan Garut, Perairan Jangari, dan daerah Outlet Waduk Cirata. Pengukuran parameter kualitas air tersebut dilaksanakan sebanyak tiga kali pengamatan dengan selang waktu tiga minggu dengan cara mengambil sampel air dari tiga stasiun kemudian dianalisa di laboratorium. Kondisi lingkungan di KJA yang meliputi kedalaman mengalami penurunan setiap bulan dan memasuki musim kemarau. Parameter yang diamati meliputi Total Fosfor, Ortofosfat, H₂S serta parameter fisika dan kimia perairan Waduk Cirata yaitu parameter fisika (suhu, kecerahan, kekeruhan dan TSS) dan parameter kimia (pH, alkalinitas, DO, BOD, dan CO2). Hasil pengamatan terhadap parameter lingkungan cukup berfluktuasi setiap bulannya yaitu nilai total fosfor di Waduk Cirata berkisar antara 0,0256 mg/l sampai 0,4125 mg/l, ortofosfat 0,0016 mg/l sampai 0,1354 mg/l, H₂S di 0,00125 mg/l sampai 0,0576 mg/l. fluktuasi harian suhu bulan Mei terjadi stratifikasi yang memiliki pola clinograde, kecerahan sedang, perairan cukup keruh, TSS relatif tinggi, pH stabil, oksigen terlarut relatif stabil, Total P sedang, Ortofosfat sedang dan H₂S melebihi batas ambang dalam budidaya ikan di KJA. Hal ini sangat berpengaruh terhadap laju pertumbuhan ikan mas dan nila yang umum dibudidayakan di tiap KJA. Adanya penumpukan sisa pakan dan hasil metabolisme ikan di dasar perairan akan mengakibatkan perubahan kualitas air dan jika terjadi umbalan akan mematikan ikan-ikan budidaya yang terjadi setiap menjelang perubahan musim terutama dari musim kemarau ke musim penghujan.
Keyword: 

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