Judul: Karakteristik Kualitas Air Muara Sungai Cisadane Bagian Tawar dan Payau di Kabupaten Tangerang, Banten.
Abstrak: Sungai Cisadane memiliki luas wilayah 1100 km2, sungai ini merupakan salah satu sungai utama di Propinsi Banten dan Jawa Barat. Penurunan kualitas air tersebut dapat terjadi sehubungan dengan masuknya berbagai limbah yang masuk ke sungai yang cenderung meningkat. Tujuan dari penelitian ini adalah mengetahui karakteristik kualitas air (tingkat pencemaran) Sungai Cisadane pada daerah muara sungai bagian tawar dan payau untuk kepentingan pengelolaan Sungai Cisadane. Hasil penelitian ini diharapkan dapat digunakan sebagai bahan pertimbangan dan masukan dalam menentukan kebijakan pengelolaan Sungai Cisadane secara berkelanjutan. Dahuri (2003) mengatakan bahwa sirkulasi air di daerah estuaria sangat dipengaruhi oleh aliran tawar yang bersumber dari badan sungai di atasnya dan air pasang yang berasal dari laut. Metode penelitian yang dilakukan adalah analisa laboratorium dan survey lapangan. Pengambilan contoh air sampel dilakukan di 2 stasiun yakni stasiun tawar yang berada di bagian tawar dari muara Sungai Cisadane (dekat Bandara Soekarno-Hatta), stasiun payau berada di bagian payau dekat pintu masuk muara Sungai Cisadane. Pengambilan sampel disesuaikan dengan saat kondisi air laut pasang dan surut. Analisis data meliputi perbandingan kualitas air permukaan dengan dasar, saat pasang dengan saat surut, dan stasiun tawar dengan staiun payau dengan uji statistik (uji t) untuk mengetahui pengaruh antara dua karakteristik kondisi (Walpole, 1995) pada air contoh muara Sungai Cisadane yang diuji. Kualitas air diketahui dengan menggunakan menggunakan Indeks Kualitas Air (IKA) STORET (Canter, 1977) dengan baku mutu PP No.82 tahun 2001 kelas 3. Kualitas air muara Sungai Cisadane tercemar baik pada bagian tawar, bagian payau, saat pasang, saat surut, lapisan permukaan, dan lapisan dasar. Kualitas air muara Sungai Cisadane tercemar berat untuk baku mutu PP RI No. 82 Tahun 2001.
Keyword: 

Judul: Water Quality Fluctuations in the Lower Cisadane River, Tangerang Regency, Banten
Abstrak: Sungai Cisadane merupakan sungai yang bersumber dari Gunung Salak dan Gunung Gede Pangrango, Kabupaten Bogor dan bermuara di Tanjung Burung, Kabupaten Tangerang. Hilir Sungai Cisadane yang dekat dengan kawasan Pantai Indah Kapuk 2 (PIK 2) menjadikannya sebagai sumber masukan air bersih bagi kawasan PIK 2. Penelitian ini bertujuan menganalisis keterkaitan pasang surut atau tinggi muka air terhadap fluktuasi beberapa parameter kualitas air di bagian hilir Sungai Cisadane. Data yang digunakan merupakan data hasil pemantauan 3 x 24 jam setiap bulan, periode tahun 2020. Pengamatan dilakukan pada satu titik dengan pengukuran in situ pada permukaan dan kolom perairan (vertikal). Keterkaitan data kualitas air berupa salinitas, DHL, TDS, suhu, DO, pH dan data pasang surut dianalisis menggunakan analisis deskriptif dan analisis regresi linier sederhana. Berdasarkan hasil analisis, pasang surut pada musim kemarau memberikan pengaruh yang signifikan pada semua parameter yaitu salinitas, DHL, TDS, suhu, DO, dan pH. Selain itu, air dari Sungai Cisadane bagian hilir yang akan digunakan sebagai sumber air bersih dan air minum di kawasan Pantai Indah Kapuk (PIK 2) tidak memenuhi baku mutu air sungai kelas 1 berdasarkan PPRI No. 22 tahun 2022. Oleh karena itu, air tersebut perlu pengelolaan lebih lanjut., Cisadane River originates from Mount Salak and Mount Gede Pangrango in Bogor Regency and ends in Tanjung Burung in Tangerang Regency. The downstream of the Cisadane River, which is close to the Pantai Indah Kapuk 2 (PIK 2) area, makes it a source of clean water input for the PIK 2 area. This study aims to analyze the relationship between tides or water levels to fluctuations in several water quality parameters in the downstream of the Cisadane River. The data used were the results of 3 x 24 hours from monthly monitoring in 2020. Observations were conducted at one site with in situ measurements on the surface and water column (vertical). The relationship between water quality data (salinity, DHL, TDS, temperature, DO, pH) and tidal data was analyzed using descriptive and simple linear regression analyses. Based on the results, tides in the dry season have a significant influence on all parameters, salinity, DHL, TDS, temperature, DO, and pH. Furthermore, water from the Cisadane River downstream, which will be used as source of clean water and drinking water in the PIK 2 residential area, does not meet the river water quality standards of class I based on PPRI No. 22 of 2021. Therefore, the water requires further management.
Keyword: Cisadane River, seasons, tides, water quality

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