Judul: Karakteristik Senyawa Polychlorinated Biphenyls (PCBs) pada Air dan Sedimen Muara Sungai Ciliwung, DKI Jakarta
Abstrak: Polychlorinated biphenyls (PCBs) is a compound that toxic, bio accumulative, persistent, and widely used in industrial activities. Ciliwung downstream in DKI Jakarta is near the industrial and residence area, so that potentially contaminated by PCBs waste. This research aims to identify the characteristic and concentration of PCBs compound in water and sediment at Ciliwung Downstream. The water samples were collected from Condet, pintu air Manggarai, Gunung Sahari, and Muara Angke, also sediment sample was collected from Muara Angke. The samples were extracted by n-hexane solution, then were analyzed by Gas Chromatography-Mass Spectrophotometry (GC-MS). The result showed that total PCBs concentration in water from Ciliwung downstream is between limit of detection (<BD) to 459.858 ppb, and 372.442 ppb in sediment. The water samples from Condet and pintu air Manggarai are dominated by high chlorination of PCBs, whereas the water sample from Gunung Sahari and sediment from Muara Angke are dominated by low chlorination of PCBs.
Keyword: water, sediment, polychlorinated biphenyls

Judul: Kandungan Logam Berat Pb, Cd, Dan Hg Pada Air Dan Sedimen Di Sungai Ciliwung, Provinsi Dki Jakarta
Abstrak: Sungai Ciliwung merupakan sungai besar yang mengalir di sepanjang daerah Jawa Barat dan DKI Jakarta. Kegiatan pembangunan di sepanjang aliran Sungai Ciliwung, baik di hulu maupun di hilir tergolong sangat intensif, sebagai dampak besarnya pembangunan di wilayah Jabodetabek sehingga memicu pencemaran yang lebih tinggi termasuk pencemaran logam berat. Penelitian ini berlangsung dari bulan Agustus 2012-Juli 2013 dan bertujuan untuk mengetahui kandungan logam berat Pb, Cd, dan Hg di perairan dan sedimen Sungai Ciliwung di Jakarta. Pengambilan data dilakukan sebanyak satu kali di Sungai Ciliwung, yang berada di wilayah Provinsi DKI Jakarta dan dibagi menjadi 3 Stasiun. Stasiun 1 berada di daerah Kelapa Dua Depok, Stasiun 2 terletak di sekitar pintu air Manggarai dan Stasiun 3 terletak di kawasan Ancol. Analisis contoh logam berat pada air dan sedimen menggunakan metode AAS (Atomic Absorption Spectrometry). Hasil penelitian di perairan Sungai Ciliwung Jakarta menunjukkan bahwa kandungan logam berat timbal pada air yaitu <0.03 mg/L, kandungan kadmium pada air yaitu <0.005 mg/L dan kandungan merkuri pada air <0.001 mg/L. Kandungan ketiga logam berat tersebut masih berada di bawah baku mutu PP No. 82 Tahun 2001. Nilai kandungan logam berat timbal pada sedimen di Sungai Ciliwung berkisar antara 27.07-34.33 mg/L. Kandungan logam berat kadmium pada sedimen yaitu <0.005 mg/L dan kandungan logam berat merkuri pada sedimen yaitu <0.005 mg/L. Berdasarkan baku mutu IADC/CEDA 1997 kandungan ketiga logam berat tersebut tergolong dalam level target dan tidak terlalu bahaya bagi lingkungan.
Keyword: air, Cd, Hg, logam berat, Pb, sedimen, Sungai Ciliwung

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