Judul: The Analysis if Rainfall Effect on Carbon Monoxide (CO) and
Nitrogen Oxide (NOx) Concentrations in the Puncak Bogor Area
Abstrak: Karbon monoksida (CO) dan Nitrogen Oksida (NOx) merupakan polutan yang sangat berbahaya bagi kesehatan manusia. Fluktuasi konsentrasi CO dan NOx tidak hanya dipengaruhi oleh aktivitas antropogenik tetapi faktor meteorologi seperti curah hujan. Penelitian ini bertujuan menganalisis pengaruh curah hujan terhadap konsentrasi CO dan NOx, dengan studi kasus Puncak Bogor tahun 2019. Data yang digunakan berupa data sekunder curah hujan dan konsentrasi CO dan NOx diperoleh dari BMKG Citeko bekerjasama dengan NIES Jepang. Analisis yang dilakukan adalah analisis data bulanan, harian, dan per menit. Hasil analisis data bulanan, curah hujan berpengaruh signifikan terhadap penurunan konsentrasi CO (r = -0,725; p-value, Carbon monoxide (CO) and Nitrogen Oxide (NOx) were pollutants that were very dangerous for human health. Fluctuations in CO and NOx concentrations are not only influenced by anthropogenic activities but meteorological factors such as rainfall. This research aims to analyze the effect of rainfall on CO and NOx concentrations, with a case study in Puncak Bogor in 2019. The data used in this study were rainfall, and CO and NOx concentrations secondary data obtained from BMKG Citeko in collaboration with NIES Japan. The data were analyzed in different time interval such as monthly, daily and minute. The results of monthly data analysis showed that rainfall has a significant effect on reducing CO concentrations (r = -0.725; p-value < 0.05), in contrast there was no significant effect on NOx concentrations (r = -0.531; p-value > 0.05). The results of daily data analysis showed that rainfall has an effect on reducing CO and NOx concentrations with a low level of correlation (r CO = -0.16 and r NOx = -0.17). The results of analysis of data per minute in certain periods of the wet month and dry season showed that rainfall has a significant effect on reducing CO and NOx concentrations, especially in the wet season. On the other hand, in the dry season, rainfall had a less significant effect on reducing CO and NOx concentrations. Based on analysis over the same time period, the average concentrations of CO and NOx were smaller when rain occurred than there were no rain occured. This showed that rainfall has an effect on reducing the concentration of CO and NOx pollutants in the Puncak Bogor area.
Keyword: curah hujan, Kualitas Udara, karbon monoksida, nitrogen oksida

Judul: Analysis of PM2.5 and Its Precursor Pollutants (NOx) Concentration Fluctuations and Their Relationship with Meteorological Factors in Rural Areas (Case Study: Puncak Bogor)
Abstrak: Wilayah Puncak Bogor merupakan wilayah rural yang didominasi oleh kegiatan pertanian. Salah satu polutan yang dihasilkan oleh aktivitas pertanian adalah ammonia (NH3), yang berkontribusi terhadap pembentukan partikulat sekuder, dengan prekursor NOx. Fluktuasi konsentrasi partikulat dan prekursornya dipengaruhi juga oleh faktor meteorologi. Penelitian ini bertujuan untuk menganalisis hubungan konsentrasi PM2.5 dengan konsentrasi prekursornya (NOx) berdasarkan fluktuasi konsentrasi di wilayah Puncak Bogor serta menganalisis faktor meteorologi yang berkontribusi terhadap fluktuasi konsentrasi PM2.5 dan prekursornya (NOx) di wilayah Puncak Bogor. Data yang digunakan adalah data konsentrasi PM2.5, NOx, NO, NO2, suhu udara, kelembaban relatif, curah hujan, serta arah dan kecepatan angin tahun 2019 dan 2020 yang dianalisis menggunakan korelasi dan regresi linier serta menggunakan package openair di RStudio. Hasil penelitian menunjukkan konsentrasi PM2.5 dengan NOx sebagai prekursornya memiliki korelasi positif yang signifikan baik pada tahun 2019 (r = 0,68) maupun tahun 2020 (r = 0,63). Peningkatan konsentrasi PM2.5 di siang hari serta penurunan konsentrasi di malam hari dikaitkan dengan adanya pengaruh angin lembah dan angin gunung yang berhembus di wilayah Puncak Bogor. Faktor meteorologi (suhu udara, kelembaban relatif, dan kecepatan angin) memiliki nilai korelasi yang kecil terhadap fluktuasi konsentrasi PM2.5, demikian pula terhadap fluktuasi konsentrasi NOx kecuali untuk suhu udara (r = 0,3)., Puncak Bogor is a rural area which is dominated by agricultural activities. One of the pollutants produced by agricultural activities is ammonia (NH3) which contributes to the secondary particulates formation, with the NOx precursor. The fluctuation of particulates and its precursor concentration are also influenced by meteorological factors. This study aims to analyze the relationship between PM2.5 concentration and its precursor (NOx) based on concentration fluctuations in Puncak Bogor and also to analyze the meteorological factors that contribute to the PM2.5 and its precursor (NOx) concentration fluctuations in Puncak Bogor. The data used are concentrations of PM2.5, NOx, NO, NO2, temperature, relative humidity, rainfall, and wind in 2019 and 2020 which were analyzed using correlation and linear regression and also using the openair package in RStudio. The results showed that PM2.5 concentration with NOx as precursors had a significant positive correlation both in 2019 (r = 0,68) and 2020 (r = 0,63). The increased and decreased of PM2.5 concentration during the day and night was influenced by valley and mountain winds that blow to the Puncak Bogor. Meteorological factors (air temperature, relative humidity, and wind speed) had a small correlation value to PM2.5 concentration fluctuations, as well as to NOx concentration fluctuations, except for air temperature (r = 0,3).
Keyword: meteorological factors, NOx, PM2.5, precursors, secondary particulates

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