Judul: Spatiotemporal Variations of NO2 and SO2 using Sentinel-5 Precursor in The Western Part of Java Island in 2019 – 2021
Abstrak: Pulau Jawa bagian barat memiliki kepadatan penduduk tertinggi di Indonesia. Aktivitas antropogenik termasuk transportasi dan industri telah meningkatkan polusi udara. Hampir seluruh NO2 dan SO2 dihasilkan dari emisi antropogenik. Distribusi gas atmosfer tersebut dapat dideteksi menggunakan satelit Sentinel-5P. Penelitian ini bertujuan mengkaji korelasi data distribusi gas NO2 dan SO2 dari satelit Sentinel-5P dengan observasi permukaan, serta mengetahui variasi spasial dan temporalnya di Pulau Jawa bagian barat dari tahun 2019 hingga 2021. Hasil menunjukkan bahwa konsentrasi NO2 dan SO2 hasil Sentinel-5P berkorelasi positif dengan hasil observasi permukaan. Konsentrasi spasial NO2 tertinggi terjadi di Jabodetabek dan Kota Cilegon dan konsentrasi spasial SO2 tertinggi di Kota Cilegon. Erupsi Gunung Anak Krakatau pada bulan Januari 2019 menyebabkan konsentrasi SO2 lebih tinggi dibandingkan tahun 2020 dan 2021. Pada saat musim hujan, konsentrasi NO2 dan SO2 menurun. Penurunan konsentrasi NO2 dan SO2 juga dipengaruhi oleh aktivitas kendaraan dan industri yang rendah pada awal pandemi COVID-19 di tahun 2020., The western part of Java Island has the highest population density in Indonesia. Anthropogenic activities, including transportation and industries, have increased air pollution. NO2 and SO2 are almost produced from anthropogenic emissions. The distribution of atmospheric gases can be detected using the Sentinel-5P satellite. This study examines the correlation of NO2 and SO2 gas distribution data from the Sentinel-5P satellite with surface measurements. It determines their spatial and temporal variations in the western part of Java Island from 2019 to 2021. The results show that the concentrations of NO2 and SO2 from Sentinel-5P were positively correlated with surface measurements. The highest spatial NO2 concentrations occur in Jabodetabek and Cilegon City, and the highest spatial SO2 concentrations occur in Cilegon City. The eruption of Mount Anak Krakatau in January 2019 caused higher SO2 concentrations compared to 2020 and 2021. During the rainy season, the concentration of NO2 and SO2 decreases. NO2 and SO2 concentrations also decreased due to the low vehicle and industrial activity at the beginning of the COVID-19 pandemic in 2020.
Keyword: air pollution, concentration, Cilegon City, Jabodetabek, meteorological factors

Judul: Analisis Spasial Persebaran Ozon Troposfer di Pulau Jawa bagian Barat
Abstrak: Ozon di atmosfer dibagi menjadi dua lapisan, yaitu ozon stratosfer dan ozon troposfer. Ozon di lapisan stratosfer melindungi bumi dari sinar ultraviolet matahari, sedangkan ozon di lapisan troposfer merupakan polutan yang berbahaya bagi kesehatan makhluk hidup. Ozon troposfer terbentuk melalui serangkaian reaksi fotokimia yang kompleks yang dibantu oleh radiasi ultraviolet dan prekursor ozon. Penelitian ini bertujuan untuk menganalisis sebaran ozon troposfer di Pulau Jawa bagian Barat secara spasial dan pengaruh NO2 dan radiasi matahari terhadap konsentrasi ozon troposfer selama tahun 2023. Variasi konsentrasi ozon troposfer dapat dianalisis dengan menggunakan metode penginderaan jauh. Salah satunya menggunakan satelit Sentinel-5P yang merupakan program pengendalian pencemaran udara dari Copernicus. Konsentrasi ozon troposfer terendah teramati pada bulan Januari dan Februari, sedangkan konsentrasi tertinggi terjadi pada bulan Oktober dan November. Hal ini dipengaruhi oleh faktor meteorologi seperti insolasi yang diterima oleh permukaan bumi dan faktor non meteorologi seperti emisi dari prekursor pembentuk ozon. Berdasarkan analisis regresi spasial, NO2 dan radiasi matahari memiliki pengaruh yang signifikan secara spasial dengan nilai P value sebesar 0 dan 0.07 terhadap konsentrasi ozon troposfer dengan selang kepercayaan yang berbeda. NO2 dan radiasi matahari mampu menjelaskan persentase konsentrasi ozon troposfer sebesar 81%., Ozone in the atmosphere is divided into two layers: stratospheric ozone and tropospheric ozone. Ozone in the stratospheric layer protects the Earth from the sun's ultraviolet rays, while ozone in the tropospheric layer is a pollutant that is harmful to the health of living beings. Tropospheric ozone is formed in a series of complex photochemical reactions assisted by ultraviolet radiation and ozone precursors. This research aims to analyze at the distribution of tropospheric ozone in the Western Part of Java Island spatially and determine the influence of NO2 and solar radiation on tropospheric ozone concentrations during 2023. Variations in tropospheric ozone concentration can be analyze using remote sensing methods. One of them is using the Sentinel-5P satellite, which is an air pollution control program from Copernicus. The lowest tropospheric ozone concentration is observed in January and February, while the highest concentration occurs in October and November. This is influenced by meteorological factors such as the insolation received by the Earth's surface and non-meteorological factors such as emissions of ozone-forming precursors. Based on spatial regression analysis, NO2 and solar radiation has a spatially significant influence with a P value of 0 and 0.07 on tropospheric ozone concentration with different confidence intervals. NO2 and solar radiation are able to explain the percentage of tropospheric ozone concentration of 81% .
Keyword: solar radiation, spatial analysis, NO2, spatial regression, tropospheric ozone

Judul: Algorithm Construction of HLI Hash Function
Abstrak: Cryptography is a study of mathematical techniques related to aspects of information security regarding on confidentiality, data integrity, entity authentication, and data origin authentication. Data integrity is a service, which is associated with the conversion of data carried out by unauthorized parties. To maintain data integrity, one can use hash functions. An hash function is a computationally efficient function to map an arbitrary length bitstring to a fixed length bitstring called as hash value. The use of hash function in maintaining the information integrity and authentication is in digital signatures, virus protection, and software distribution. Illustration of the hash function in the integrity and authentication of information that is emailed as follow. The sender sends the information and hash value to the recipient. If the hash value of the information is equal to the hash value that is sent by the sender, then information has not been changed. Otherwise the information has been changed. An hash function has two properties, one way and collision resistance. An hash function is called one way if it is computationally infeasible to find any input such that when given any hash value . Meanwhile an hash function is called collision resistant if it is computationally infeasible to find any two inputs where such that . The purpose of this study is to construct a HLI hash function algorithm, to analyze the speed and security of the hash functions as a results of construction. Furthermore, it is to compare it with SWIFFT. Hash function is constructed based on the result of algebraic operations on modular polynomial ringwith . Modular polynomial ring noted as is a set of all polynomials of degree at most with coefficients in . can be represented as a set of integer vector of modulo in dimension . So, it is simple to implement in a computer. In vector operations, is lattice . Furthermore, alattice that is defined from certain polynomial ring is called ideal lattice. HLI hash function is consists of addition and multiplication algorithm in the ring. Addition algorithm consists of sumation operations of modulo and multiplication consists of multiplication operations of modulo . Generally, algorithm of HLI hash function consists of multiplication operations of modulo and addition operations of modulo . However, if the input is binary number then multiplication algorithm only consists of multiplication operation of modulo , so algorithm of HLI hash function consists of multiplication operations of modulo and addtion operations of modulo . An hash function is secured if it has two properties, i.e., one way and collision resistance. HLI hash function hash is one way, it is following the proof of Micciancio. It is has collision resistant because of polynomial is irreducible over and monic. Moreover, it is proved that for every unit vector , the vector is small vector. If the input of hash function is a binary number then HLI hash function only involves addition operations of modulo . So the time that used almost same with SWIFFT. The excellence of HLI hash function is the key size smaller than SWIFFT. This effect on
Keyword: hash function, modular polynomial ring, lattice