Judul: The Impact of Land Use Change on the  Urban Heat Island Phenomenon in the City of Surabaya
Abstrak: Pembangunan Kota Surabaya yang meningkat pesat berimplikasi pada bertambahnya lahan terbangun, sehingga terjadi peningkatan suhu udara yang mempengaruhi fenomena urban heat island (UHI). Teknologi penginderaan jauh dapat digunakan untuk menganalisis pengaruh perubahan penggunaan lahan terhadap fenomena UHI di perkotaan. Penelitian ini bertujuan untuk menerangkan fenomena UHI di Kota Surabaya pada tahun 2015-2020 menggunakan data citra satelit. Citra Landsat 8 Kota Surabaya dianalisis untuk mendapatkan peta penggunaan lahan, suhu udara, dan urban thermal field variance index (UTFVI) rata-rata. Hasil penelitian menunjukkan bahwa Kota Surabaya mengalami perubahan penggunaan lahan sebesar 18% atau 6017,48 ha. Distribusi suhu udara mengalami peningkatan sebesar 1,01-3,11 °C dengan pola sebaran suhu maksimum di pusat kota dan minimum di pinggiran kota. Fenomena UHI Kota Surabaya menunjukkan tren yang serupa, pusat kota memiliki nilai UTFVI dengan ambang batas > 0,02 yang mengindikasikan fenomena UHI paling kuat. Efek UHI ini menyebar ke wilayah pinggiran Kota Surabaya seiring pembangunan lahan perkotaan., The rapidly improving development of the city of Surabaya has implications for expanding built-up land, increasing air temperature, which affects the urban heat island (UHI) phenomenon. Remote sensing technology can be used to analyze land-use change on the UHI phenomenon in urban areas. This study aims to explain the UHI phenomenon in Surabaya in 2015-2020 using satellite image data. Landsat 8 images of Surabaya City were analyzed to obtain land-use maps, air temperature, and average urban thermal field variance index (UTFVI). The results showed that the city of Surabaya experienced a change of land use by 18% or 6017.48 ha. The air temperature distribution increased by 1.01-3.11 °C with a maximum temperature distribution pattern in the city center and a minimum temperature distribution in the suburbs. The UHI phenomenon in Surabaya City shows a similar trend. The city center has a UTFVI value with a threshold of > 0.02, indicating the most robust UHI phenomenon. This UHI effect spreads to the suburbs of Surabaya City along with the development of urban land.
Keyword: air temperature, land use, urban heat island

Judul: Urban Heat Island and Land Cover Analysis in Greater Jakarta
Abstrak: Jabodetabek merupakan kawasan kota besar yang memiliki perkembangan pesat. Perkembangan ini telah banyak mengonversi lahan vegetasi menjadi lahan terbangun. Perubahan lahan tersebut menyebabkan peningkatan suhu permukaan tanah yang signifikan di daerah perkotaan, yang dikenal dengan fenomena Urban Heat Island (UHI). Penelitian ini bertujuan untuk mengidentifikasi UHI dan hubungannya dengan tutupan lahan di Jabodetabek. Analisis yang dilakukan menggunakan citra satelit Landsat 5 dan Landsat 8 tahun 1993, 1999, 2006, 2013, 2018, dan 2023 untuk estimasi suhu permukaan dan klasifikasi tutupan lahan. Klasifikasi tutupan lahan menggunakan metode klasifikasi terbimbing. Hasil penelitian menunjukkan bahwa suhu permukaan di wilayah perkotaan lebih tinggi daripada pedesaan hingga sebesar lebih dari 3, Greater Jakarta is a large city with rapid development. This development has converted a lot of vegetation land into built-up land. The changed land causes a significant increase in land surface temperature in urban areas, known as Urban Heat Island (UHI). This study aims to identify the UHI and its relationship with land cover in Greater Jakarta. The analysis used Landsat 5 and Landsat 8 satellite images in 1993, 1999, 2006, 2013, 2018 and 2023 for estimating land surface temperature and classifying land cover. Land cover classification using supervised classification. The results show that the surface temperature in urban areas is higher than rural areas by
Keyword: urban heat island, regression, land surface temperature, remote sensing, land cover

Judul: The Exploration of Discrete Logarithm over Finite Field GF(3m)
Abstrak: The security of many public~key algorithms is based on the problem of finding discrete logarithms. The generalized discrete logarithm problem is the following: given a finite cyclic group G of order n, a generator a of G, and an element fl E G, find the integer x, 0 ~ x ~ n - 1, such that 0: = fl. Algorithm for discrete logarithm problem focused on Menezes et al. (1997) that consist of exhaustive search algorithm, the baby-step giant-step algorithm, Pollard's rho algorithm, Pohlig-Hellman algorithm, and index-calculus algorithm. These algorithms are explorated to be used in discrete logarithm problem over finite field GF(3m ). The exploration also produces some algorithms, i.e. naif negative algorithm, baby-step mother-step algorithm, baby-step mother free-step algorithm, and baby-step free-step algorithm. All algorithms implemented using Maple 11. The Pohlig-Hellman and baby-step giant-step algorithms are efficient enough to be used in discrete logarithm problem over finite field GF(3m ) for m < 20.
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