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: Analysis Of SO2 Spread In Covid-19 Outbreak Season Using  Aura Satellite In Jabodetabek Area
Abstrak: Jabodetabek area is the area with the highest population in Indonesia. The high activity affects the air quality of the Jabodetabek Area, one of the reasons for the change in air quality is the large use of fossil energy that produces pollutants that are harmful to human health, one of which is SO2. Since it was announced on March 2, 2020, the number of cases of people exposed to Covid-19 continues to increase, prompting the Jabodetabek Regional government to implement a LargeScale Social Restrictions (PSBB) policy to reduce the increase in the number of Covid-19 cases. This study was conducted to determine the change in SO2 concentration before and during the implementation of the PSBB Satelit Aura policy starting from 2019 and 2020. The results of this study showed a decrease in SO2 concentration since January 2019 of 36,918 μg/m3 and at the time PSBB policy was applied SO2 concentrations moved constantly. This can happen due to the increase in the amount of public transportation before the PSBB policy was enacted and the decrease in community activity at the time the PSBB policy was implemented to reduce the use of fossil fuels that produce SO2 pollutants, Wilayah Jabodetabek merupakan wilayah dengan penduduk dengan Aktivitas tertinggi di Indonesia. Tingginya aktivitas tersebut mempengaruhi kualitas udara Wilayah Jabodetabek, salah satu sebab terjadinya perubahan kualitas udara adalah banyaknya penggunaan energi fosil yang menghasilkan polutan pencemar udara seperti SO2. Sejak diumumkan pada 2 Maret 2020, jumlah kasus masyarakat terpapar Covid-19 terus meningkat, hal tersebut mendorong pemerintah Wilayah Jabodetabek untuk melakukan kebijakan Pembatasan Sosial Berskala Besar (PSBB) untuk menekan kenaikan jumlah kasus Covid-19. Penelitian ini dilakukan untuk mengetahui perubahan konsentrasi SO2 sebelum dan pada saat pemberlakuan kebijakan PSBB Satelit Aura terhitung sejak tahun 2019 dan tahun 2020. Hasil penelitian ini menunjukkan adanya penurunan konsentrasi SO2 sejak Januari 2019 sebesar 36,918 µg/m3 dan pada saat kebijakan PSBB diberlakukan konsentrasi SO2 bergerak secara konstan. Hal ini dapat terjadi akibat kenaikan jumlah transportasi umum pada sebelum kebijakan PSBB diberlakukan dan berkurangnya aktivitas masyarakat pada saat kebjakan PSBB diberlakukan sehingga menurunkan penggunakan bahan bakar fosil yang menghasilkan polutan SO2.
Keyword: air pollution, covid-19, satellite aura

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