Judul: Estimasi Sebaran Konsentrasi Maksimum SO2 dan Partikulat di Kota Cilegon menggunakan Model WRF-Chem
Abstrak: Kota Cilegon merupakan kota dengan kawasan industri yang berkontribusi terhadap peningkatan pencemar udara seperti SO2 dan partikulat (PM10) yang dapat mempengaruhi kesehatan masyarakat sekitar. Pemantauan kualitas udara menjadi salah satu langkah untuk pengendalian pencemaran udara dan dampaknya, namun alat pemantau kualitas udara di Kota Cilegon masih terbatas. Model WRF-Chem (Weather Research and Forecasting-Chemistry) dapat digunakan untuk mengidentifikasi wilayah yang berpotensi terpapar sebaran pencemar dengan konsentrasi maksimum. Penelitian ini bertujuan untuk mengetahui pola dispersi dan mengestimasi sebaran konsetrasi maksimum SO2 dan PM10 di Kota Cilegon berdasarkan luaran model. Berdasarkan analisis pola dispersi konsentrasi pencemar luaran model WRF-Chem menunjukkan bahwa sebaran konsentrasi maksimum SO2 didominasi berada di bagian Timur dan Selatan Kota Cilegon. Sementara itu sebaran konsetrasi maksimum PM10 didominasi berada di bagian Utara Kota Cilegon. Secara keseluruhan hasil model menunjukkan bahwa wilayah Kecamatan Jombang dan Cibeber merupakan wilayah yang paling berpotensi terpapar konsentrasi maksimum SO2 dengan frekuensi cukup tinggi (220-224 jam pada September dan 163-190 jam pada Januari selama periode running 336 jam) dan nilai konsentrasi maksimum mencapai 0.075 μg/m3 pada September dan 0.033 μg/m3 pada Januari. Sedangkan Kecamatan Pulomerak merupakan wilayah yang paling berpotensi terpapar konsentrasi maksimum PM10 dengan frekuensi cukup tinggi dibandingkan dengan wilayah lain (13 jam untuk September dan sebanyak 8 jam untuk Januari dengan nilai konsentrasi maksimum mencapai 0.27 μg/m3 pada September dan 1.2 μg/m3 pada Januari. Nilai konsentrasi hasil model masih underestimate, namun nilai korelasi untuk parameter meteorologi cukup tinggi (R=0.89) untuk suhu udara sehingga berdasarkan faktor meteorologinya model WRF-Chem dapat digunakan untuk mensimulasikan sebaran konsentrasi pencemar.
Keyword: Cilegon, konsentrasi maksimum, polusi udara, WRF-Chem

Judul: Model Prediksi Distribusi Laju Penyebaran Sulfur Dioksida (SO2)dan Debu dari Kawasan Industri (Studi Kasus di Kota Cilegon)
Abstrak: This study aims to examine the characteristics of local air; analyze the concentration of air pollution emitted from factories located in an industrial area; and predict air pollution distribution the city of Cilegon. Several sequential steps of analysis are carried out which include: (1) calculation of high-layer pollutant mixing in the atmosphere (mixing height), (2) analysis of emission of air pollutant from the source point using screen3 model; (3) analysis of distribution of air pollutant from the industrial area using general transport equation of unsteady flow. Based on climatology, Pasquill stability criterian indicate that stability profile in the region ranges from A (very unstable) to E (slightly stable). Pollutant distribution from the industry depends on the height of the chimney. The higher the chimney is, the further the distribution of the pollutant as a result of emission is expected to be. The highest concentration of SO2 is found in the emission of industry area, with atmosfheric stability class A (very unstable), whereas furthest distance occurred stability E class (slightly stable). The distribution of SO2 extends towards Tamansari village of Pulomerak District. From 24 sampling points, the highest concentration of 55,75 ìg/m3 occurred in the ASDP Merak. The levels and patterns of air pollutant distribution in the area need to be taken into account, particularly in the interest of protecting public healthlife from the impacts caused by the pollutant.
Keyword: General equation of transport, Screen3, Unsteady flow, Banten, Characteristics of local air

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