Judul: Relationship between Leaf Area Index (LAI) and Microclimate in Star Energy Geothermal Salak Revegetation Land
Abstrak: Kegiatan sektor panas bumi yang menggunakan bahan bakar fosil menghasilkan CO2 yang dapat menimbulkan efek rumah kaca dan pemanasan global. Pelestarian lingkungan pasca tambang telah dilakukan oleh Star Energy Geothermal Salak dengan cara melakukan program revegetasi lahan. Penelitian ini bertujuan untuk mengkaji hubungan antara kerapatan tajuk dan iklim mikro dengan indikator suhu udara, kelembapan udara, dan intensitas cahaya matahari pada lahan revegetasi. Analisis data dilakukan dengan pengukuran suhu dan kelembapan udara, pengukuran intensitas cahaya matahari, pengambilan foto Leaf Area Index (LAI), dan metode analisis regresi linear berganda. Hasil penelitian menunjukkan bahwa terdapat hubungan antara suhu udara dan kelembapan udara sebagai variabel terikat dengan intensitas cahaya matahari dan LAI sebagai variabel bebas yang dapat dilihat dari hasil analisis regresi linear berganda. Model regresi dapat menjelaskan sebesar 43% perubahan pada variabel suhu udara dan sebesar 40% perubahan pada variabel kelembapan udara dapat dijelaskan oleh variabel independen dalam model. Selain itu, hasil akhir menunjukkan tajuk pohon yang rapat dapat memperbaiki kondisi iklim mikro di Star Energy Geothermal Salak., Geothermal sector activities that use fossil fuels produce CO2 which can cause the greenhouse effect and global warming. Environmental preservation has been carried out by Star Energy Geothermal Salak by conducting a land revegetation program. This study aims to assess the relationship between canopy density and microclimate with indicators of air temperature, air humidity, and sunlight intensity on revegetated land. Data analysis was carried out by measuring air temperature and humidity, measuring sunlight intensity, taking photos of Leaf Area Index, and multiple linear regression analysis methods. The results showed that there is a relationship between air temperature and air humidity as the dependent variable with sunlight intensity and LAI as independent variables which can be seen from the results of multiple linear regression analysis. The regression model can explain 43% of changes in the air temperature variable and 40% of changes in the air humidity variable can be explained by the independent variables in the model.In addition, the final results show that dense tree crowns can improve microclimateconditions at Star Energy Geothermal Salak.
Keyword: pemanasan global, iklim mikro, regresi linier berganda, microclimate, multiple linear regression, global warming

Judul: EVALUATION OF LANDSAT IMAGE IN ESTIMATING SURFACE TEMPERATURE ON VARIOUS LAND COVERS USING SPLIT WINDOW ALGORITHM  (Case Study: Revegetation Ex-mine Area in Air Buluh Village)
Abstrak: Suhu permukaan lahan merupakan parameter penting dalam berbagai macam studi ilmiah seperti ekologi, hidrologi, dan pemanasan global. Karakteristik tanah dan penggunaan tutupan lahan sangat mempengaruhi nilai suhu permukaan. Penelitian ini bertujuan mengetahui hubungan karakteristik tanah terhadap suhu tanah serta perubahan suhu spasial yang disebabkan oleh perubahan tutupan lahan menggunakan metode split window algorithm di wilayah Desa Air Buluh. Puncak penambangan tahun 2010 mengakibatkan lahan bekas tambang mencapai luas 400,2 Ha. Revegetasi membuat penurunan lahan bekas tambang menjadi 62,8 Ha pada tahun 2019. Revegetasi dilakukan dengan menjadikan lahan untuk area pertanian dan perkebunan. Perubahan tutupan lahan akibat aktivitas penambangan sebelum tahun 2010 mempengaruhi nilai kenaikan suhu permukaan. Sedangkan kegiatan revegetasi setelah tahun 2010 mempengaruhi penurunan suhu permukaan. Nilai suhu permukaan paling tinggi terdapat pada tahun 2003 sebesar 31,8°C, dan nilai suhu paling rendah terdapat pada tahun 2015 sebesar 20,1°C. Tutupan lahan sawit >10 tahun di lapangan menunjukan nilai suhu permukaan paling rendah sebesar 27,7°C±1, sedangkan nilai suhu permukaan paling tinggi di lapangan terdapat pada ladang pertanian sebesar 34,2°C±2,6. Penelitian ini menunjukan keterkaitan suhu tanah kedalaman 0cm dengan suhu citra satelit merupakan parameter terbaik dengan tingkat akurasi MAD 1,10, RMSE 1,26, dan R² > 0,5. Pola suhu tanah menunjukan semakin dalam kedalaman tanah maka suhu tanah semakin rendah. Nilai suhu tanah menunjukan semakin rendah kandungan bahan organik, air tanah, dan kemampuan legas tanah menyebabkan suhu tanahnya tinggi. Kata kunci: bekas tambang, pengindraan jauh, suhu permukaan, tutupan lahan, Land surface temperature is an important parameter in various scientific studies such as ecology, hydrology, and global warming. Soil characteristics and land cover use greatly affect the value of surface temperature. This study aims to determine the relationship between soil characteristics and soil temperature and changes in spatial temperature caused by land cover changes using the split window algorithm method in the Air Buluh Village area. The peak of mining in 2010 resulted in ex-mining land reaching an area of 400.2 Ha. Reclamation reduces exmining land to 62.8 hectares in 2019. Reclamation is carried out by converting land to agricultural and plantation areas. Changes in land cover due to mining activities prior to 2010 affect the value of the increase in surface temperature. Meanwhile, reclamation activities after 2010 affect the decrease in surface temperature. The highest surface temperature value was in 2003 at 31.8°C, and the lowest temperature value was in 2015 at 20.1°C. Oil palm land cover >10 years in the field shows the lowest surface temperature value of 27.7°C±1, while the highest surface temperature value in the field is found in agricultural fields of 34.2°C±2.6. This study shows the relationship between 0cm depth soil temperature and satellite image temperature is the best parameter with an accuracy level of MAD 1.10, RMSE 1.26, and R² > 0.5. The soil temperature pattern shows the deeper the depth of the soil, the lower the soil temperature. The value of soil temperature shows that the lower the content of organic matter, groundwater, and the ability of the soil to release soil causes the soil temperature to be high. Keywords: ex-mining land, land cover, remote sensing, surface temperature
Keyword: ex-mining land, land cover, remote sensing, surface temperature

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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