Judul: Kajian beban pencemaran Sungai Cikao Kabuapten Purwakarta
Abstrak: Kondisi Sungai Cikao saat ini diperkirakan telah mengalami penurunan kualitas air disebabkan berbagai aktivitas manusia. Penelitian ini bertujuan untuk mengidentifikasi sumber pencemar air Sungai Cikao, menghitung besar beban pencemaran setiap sumber-sumber pencemar dan dampak beban pencemaran (BP) terhadap kualitas air dan membandingkan besar BP dengan daya tampung beban pencemaran (DTBP). Analisis beban pencemaran dilakukan melalui pendekatan Rapid Assesment, sedangkan status pencemaran dianalisis dengan metode Storet. Hasil identifikasi menunjukkan bahwa sumber pencemar dominan di sekitar Sungai Cikao adalah limbah permukiman, pertanian, peternakan dan industri, dengan total beban pencemaran terhadap nilai BOD sebesar 478.188 ton/bulan, COD sebesar 941.418 ton/bulan, TSS sebesar 240.840 ton/bulan dan TN sebesar 242.274 ton/bulan. Selisih antara DTBP terhadap BP pada nilai BOD sebesar -3 755.593 ton/tahun, COD sebesar 5 225.217 ton/tahun, TSS sebesar 3 718.810 ton/tahun dan TN sebesar 30 069.427 ton/tahun. Hasil analisis status pencemaran dengan metode Storet menunjukkan bahwa kualitas air di Sungai Cikao termasuk kategori tercemar berat
Keyword: Cikao River, pollution resource, waste discharge, water quality

Judul: Pollution Load Analysis of  Cikeas River West Java Province
Abstrak: Sungai Cikeas berperan penting sebagai sumber air tawar. Seiring perkembangan wilayah Sungai Cikeas mengalami perubahan tutupan lahan yang berdampak pada pencemaran Sungai Cikeas. Penelitian ini bertujuan untuk memberikan gambaran kondisi terbaru kualitas air Sungai Cikeas dan besarnya beban pencemaran dari berbagai sumber pencemar pada berbagai tutupan lahan di Sungai Cikeas. Analisis tutupan lahan menggunakan metode OBIA. Status mutu air dianalisis menggunakan metode indeks pencemaran dan baku mutu kelas II. Besarnya beban pencemaran dihitung menggunakan metode rapid assessment. Tutupan lahan DAS Cikeas mengalami perubahan dari lahan pertanian dan hutan menjadi lahan terbangun. Pada periode 2018-2021 Sungai Cikeas berada dalam status tercemar yang berfluktuasi dari cemar berat, sedang, dan ringan. Potensi beban pencemaran terbesar berasal dari sektor industri dan domestik dengan BOD sebesar 18.961,91 ton/tahun, COD sebesar 47.265,24 ton/tahun, dan TSS sebesar 23.182,62 ton/tahun. Pengaruh beban pencemaran terhadap kualitas air, sesuai dinamika debit Sungai Cikeas, menyebabkan peningkatan parameter BOD 3,09- 12,78 mg/l, COD 7,70-31,51 mg/l, dan TSS 3,78-15,46 mg/l.
Keyword: Cikeas River, land cover change, pollution load

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