Judul: Analysis of The Relationship Between Urban Heat Island Intensity and Temperature Criticality Value in Denpasar City
Abstrak: Pemadatan bangunan di Kota Denpasar menyebabkan terjadinya urban heat island (UHI) yang bisa diukur dengan Urban Thermal Field Variance Index (UTFVI) dan Environment Criticality Index (ECI). ECI adalah perbandingan suhu permukaan lahan terhadap Normalized Difference Vegetation Index (NDVI). Penelitian ini mengembangkan ECI menjadi Temperature Criticality Value (TCV) yang diperoleh dari suhu udara dan Index-based Built-up Index (IBI). Penelitian bertujuan mengetahui intensitas UHI, pengaruh perubahan tutupan lahan, dan hubungan TCV dengan intensitas UHI. Analisis menggunakan data citra satelit Landsat 8 dan pengukuran lapang. Wilayah kajian didominasi oleh lahan terbangun yang meningkat dari 2015 hingga 2021. UTFVI menunjukkan dominasi intensitas UHI sangat kuat (>0,02) yaitu pada lahan terbangun. Rata-rata NDVI mengindikasikan penurunan kerapatan vegetasi. IBI mengindikasikan peningkatan kepadatan bangunan, berbanding terbalik dengan kondisi vegetasi. TCV pada 2015 berkisar antara -11.15°C.IBI hingga 6.42°C.IBI; 2018 antara -9.96°C.IBI hingga 6.79°C.IBI; dan 2021 antara -10.84°C.IBI hingga 6.87°C.IBI. Hal tersebut menunjukkan kondisi lingkungan semakin kritis. Intensitas UHI yang lebih kuat, bangunan yang lebih padat, dan lingkungan yang lebih kritis terjadi di pusat kota dibandingkan suburban berdasarkan analisis transek. Koefisien korelasi (r) TCV dan UTFVI tergolong cukup kuat (0,75–0,82), sehingga peningkatan intensitas UHI berhubungan dengan lingkungan yang lebih kritis. TCV memiliki korelasi paling kuat dengan indeks keterbangunan (r=0,99) dan korelasi kuat (r>0,80) namun berbanding terbalik dengan NDVI. Oleh karena itu, kekritisan lingkungan dapat dikontrol dengan pembatasan lahan terbangun dan penambahan vegetasi., The buildings’ compaction in Denpasar causes urban heat island (UHI) which can be measured by Urban Thermal Field Variance Index (UTFVI) and Environment Criticality Index (ECI). ECI is the ratio of land surface temperature to the Normalized Difference Vegetation Index (NDVI). In this study, ECI was developed into Temperature Criticality Value (TCV) that was obtained from air temperature and Index-based Built-up Index (IBI). This study aims to determine the UHI intensity, the effect of land cover changes, and the relationship between TCV and UHI intensity. The analysis uses Landsat 8 imagery and field measurements data. This study area is dominated by built-up land, which increased from 2015 to 2021. UTFVI shows very strong UHI (>0.02) domination that occurs on built-up land. Mean value of NDVI indicates a decrease in vegetation density. Built-up density (IBI) has increased, inversely with vegetation. TCV in 2015 ranged from - 11.15°C.IBI to 6.42°C.IBI; 2018 between -9.96°C.IBI to 6.79°C.IBI; and 2021 between -10.84°C.IBI to 6.87°C.IBI. This shows that the environment is increasingly critical. Stronger UHI intensity, denser buildings, and more critical environment occur in the urban centers than in suburbs based on transect analysis. The correlation coefficient (r) of TCV and UTFVI is quite strong (0,75–0,82), so the increase of UHI intensity correlated with a more critical environment. TCV has the strongest correlation with Built-up Index (r=0.99) and strong (r>0,80) but inverse correlation with NDVI. Therefore, environment criticality can be controlled by limiting the expansion of the built-up area and increasing vegetation.
Keyword: built-up area, environment conditions, Landsat 8, urban heating, vegetation density

Judul: Analysis of Environmental Critical based on Environmental Criticality Index and Urban Heat Island Phenomenon in Bima City
Abstrak: Konversi lahan vegetasi menjadi lahan terbangun yang terjadi di Kota Bima mendorong terjadinya urban heat island (UHI) dan penurunan kualitas lingkungan yang dapat mempengaruhi kualitas hidup masyarakat dan pembangunan berkelanjutan di Kota Bima. Kekritisan lingkungan dapat diduga menggunakan Environmental Crticality Index (ECI) yang merupakan nilai rasio Normalized Difference Vegetation Index (NDVI) dan suhu permukaan tanah. Pada penelitian ini, ECI dikembangkan menjadi persamaan suhu udara dan Built-up Area Index (BU). Penelitian ini bertujuan mengetahui tingkat kekritisan lingkungan di Kota Bima berdasarkan nilai ECI dan mengetahui hubungan antara UHI dengan ECI di Kota Bima. Analisis dilakukan dengan menggunakan citra satelit Landsat 8 dan pengukuran lapangan. Hasil dari penelitian ini, Kota Bima memiliki kisaran nilai NDVI -0.16 - 0.61 dengan nilai NDVI di perkotaan lebih rendah dibandingkan di pinggiran kota. Kisaran nilai BU -1 - 0.2 dengan BU di wilayah perkotaan lebih tinggi dibandingkan di pinggiran kota. Nilai UHI di Kota Bima tinggi pada tahun 2021. Nilai ECI menunjukan bahwa dari tahun 2015 hingga 2021 lingkungan semakin kritis di wilayah perkotaan. Wilayah pesisir Kota Bima memiliki nilai ECI yang tinggi artinya kondisi lingkungannya telah memasuki kondisi kritis dan juga diidentifikasi terjadi fenomena UHI. Korelasi (r) ECI dengan UHI di Kota Bima cukup kuat (0.36 – 0.55), namun korelasi ECI dengan NDVI dan ECI dengan BU sangat kuat (0.95 – 0.96) dan (0.943 – 0.975)., The conversion of vegetated land into built-up land that occurs in the City of Bima encourages the occurrence of urban heat islands (UHI) and a decrease in environmental quality that can affect the community's quality of life and sustainable development in the City of Bima. Environmental criticality can be estimated using the Environmental Criticality Index (ECI), which is the ratio value of the Normalized Difference Vegetation Index (NDVI) and soil surface temperature. In this study, ECI was developed into an equation of air temperature and Built-up Area Index (BU). This study aims to determine the level of environmental criticality in Bima City based on the ECI value and determine the relationship between UHI and ECI in Bima City. The analysis was carried out using Landsat 8 satellite imagery and field measurements. In this study, Bima City has an NDVI value range of -0.16 - 0.61, with a lower NDVI value in urban areas than in the suburbs. The range of BU values is -1 - 0.2, with BU in urban areas being higher than in the suburbs. The UHI value in Bima City is increased in 2021. The ECI value shows that from 2015 to 2021, the environment is increasingly critical in urban areas. The coastal area of Bima City has a high ECI value, meaning that the environmental conditions have entered a critical condition, and the UHI phenomenon has also been identified. The correlation (r) of ECI with UHI in Bima City is quite strong (0.36 – 0.55), but the correlation of ECI with NDVI and ECI with BU is very strong (0.95 – 0.96) and (0.943 – 0.975).
Keyword: air temperature, built-up area index, environmental criticality index, normalized difference vegetation index, urban heat island

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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