Judul: Spatial Analysis of Oil Palm Evapotranspiration Using METRIC Model
Abstrak: Estimasi Evapotranspirasi (ET) di perkebunan kelapa sawit menjadi penting untuk dilakukan agar mendapatkan informasi terkait kehilangan air dari permukaan (evaporasi) dan tanaman (transpirasi). Dewasa ini, beberapa model keseimbangan energi untuk mengestimasi ET telah banyak dikembangkan tidak hanya dalam analisis secara temporal tetapi juga dapat menentukan distribusi spasial evapotranspirasi. Tujuan utama penelitian ini yaitu dapat mengestimasi dan menentukan distribusi spasial evapotranspirasi berbagai umur tanaman menggunakan model Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) di perkebunan kelapa sawit PT. Teladan Prima Agro (TPA), Kalimantan Timur. Analisis pada penelitian ini menggunakan data citra satelit Landsat-8 (OLI/TIRS) dan data cuaca yang diperoleh dari data ERA-5 Reanalysis. Parameter permukaan yang perlu diperhitungkan yaitu Normalized Different Vegetation Index (NDVI), suhu permukaan, albedo permukaan, emisivitas, panjang kekasapan, radiasi netto (Rn), fluks bahang tanah (G), fluks bahang terasa (H), dan fluks bahang laten (LE) sehingga diperoleh nilai evapotranspirasi harian pada wilayah kajian. Hasil menunjukkan nilai evapotranspirasi tanaman kelapa sawit dewasa 30% lebih tinggi dibandingkan tanaman yang masih muda. Tanpa seleksi pada cold dan hot pixel menunjukkan nilai evapotranspirasi yang berbeda nyata (P-value < 0.05). Nilai koefisien determinasi yang diperoleh dengan seleksi piksel lebih tinggi dibandingkan tanpa seleksi piksel antara evapotranspirasi yang diestimasi dengan evapotranspirasi dari Earth Engine Flux (EEFLUX) dan metode Penman-Monteith FAO 56. Selain itu, nilai LE-H menunjukkan kondisi permukaan perkebunan tanaman kelapa sawit yang lebih kering pada tahun 2015 dan konvergensi energi yang terjadi pada akuisisi citra tahun 2020. Kata kunci : evapotranspirasi, Landsat-8, neraca energi, penginderaan jauh, model METRIC, Estimation of Evapotranspiration (ET) in oil palm plantations is crucial to conduct to obtain water loss information from a surface (evaporation) and plants (transpiration). At present time, energy balances models have been developed not only need for temporal analysis, but also for determining the spatial distribution of evapotranspiration. The research objective is to determine and estimate the spatial distribution of evapotranspiration at various oil palm ages using the Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) model in PT. Teladan Prima Agro (TPA), East Kalimantan. Landsat 8 imagery and climate data obtained from ERA-5 Reanalysis are used in this research. We calculated Normalized Different Vegetation Index (NDVI), land surface temperature (Ts), surface albedo, emissivity, and roughness length. Thereafter, energy balance components viz. net radiation (Rn), ground heat flux (G), sensible heat flux (H), and latent heat flux (LE) are used to estimate the daily evapotranspiration of oil palms. Results show evapotranspiration in mature oil palms is 30% greater than in young oil palms. Evapotranspiration with and without selection shows a significant difference (P-value < 0.05). Result also shows the coefficient of determination value with pixel selection higher than without pixel selection between estimated evapotranspiration, Earth Engine Flux (EEFLUX) and Penman-Monteith FAO 56 method. In addition, LE-H values show more drier conditions in oil palm surface in 2015 and energy convergence occurring at acquisition imagery in 2020. Keywords : evapotranspiration, energy balance, Landsat-8, remote sensing, METRIC model
Keyword: evapotranspiration, landsat-8, model metric, penginderaan jauh, neraca energi

Judul: Relationship Between Net Ecosystem Exchange (NEE) and Evapotranspiration (ET) in Oil Palm: Control of Water Availability and VPD on Water Use Efficiency (WUE)
Abstrak: Perkebunan kelapa sawit merupakan salah satu ekosistem terestrial yang berperan penting dalam siklus karbon global serta memiliki kemampuan menyerap karbon sekitar 76 ton CO2 per hektar per tahun. Fluks air dan karbon pada agroekosistem menjadi fokus dari studi hubungan pangan-energi-air. Penelitian ini dilakukan di PT Perkebunan Nusantara (PTPN) VI, Batanghari, Jambi dengan tujuan untuk menganalisis hubungan antara Net Ecosystem Exchange (NEE) dan evapotranspirasi (ET) di perkebunan kelapa sawit dalam rentang diurnal selama periode basah dan kering. Analisis menggunakan data periode basah bulan April 2015, Oktober 2017, dan Januari 2018 serta periode kering bulan Juli 2015, Agustus 2019, dan Juli 2020. Pengukuran dilakukan dengan menggunakan metode Eddy Covariance (EC) yang menghasilkan data Net Ecosystem Exchange (NEE) (µmol/m2/s) dan evapotranspirasi (ET) (mmol/m2/s). Hubungan antara Net Ecosystem Exchange (NEE) dan evapotranspirasi (ET) dianalisis dengan menggunakan koefisien determinasi (R^2) dan koefisien korelasi (r) dengan metode Pearson. Hasil penelitian menunjukkan adanya hubungan antara NEE dan ET selama periode basah dan kering yang berada pada kategori sangat kuat. Pada periode basah dan kering diurnal, koefisien determinasi (R^2) sebesar 0,958 dan 0,879, sedangkan koefisien korelasi (r) sebesar 0,979 dan 0,937. Adapun periode basah dan kering siang hari (R^2) sebesar 0,923 dan 0,810, sedangkan (r) sebesar 0,962 dan 0,9. Hubungan antara NEE dan ET kemudian dikaitkan dengan Water Use Efficiency (WUE) sebagai rasio antara NEE/ET (g CO2/kg H2O). Nilai WUE selama periode basah dan kering cenderung tinggi pada pagi hari dan menurun menjelang siang hari dengan rata-rata WUE periode basah yaitu 3,452 g CO2/kg H2O dan periode kering sebesar 3,361 g CO2/kg H2O. Selain itu, ditemukan bahwa WUE dapat menurun pada kondisi VPD yang tinggi. Kecenderungan terjadinya penurunan pada variabel yang dianalisis selama periode kering dan periode basah dikarenakan adanya perbedaan ketersediaan air., Oil palm plantations are one of the terrestrial ecosystems that play an important role in the global carbon cycle and can absorb carbon around 76 tons of CO2 per hectare per year. Water and carbon fluxes in agroecosystems are the focus of food-energy-water relationship studies. This study was conducted at PT Perkebunan Nusantara (PTPN) VI, Batanghari, Jambi, to analyze the relationship between Net Ecosystem Exchange (NEE) and evapotranspiration (ET) in oil palm plantations in a diurnal range during wet and dry periods. The analysis used data from the wet periods of April 2015, October 2017, and January 2018 and the dry periods of July 2015, August 2019, and July 2020. Measurements were made using the Eddy Covariance (EC) method, which produced Net Ecosystem Exchange (NEE) (µmol/m2/s) and evapotranspiration (ET) (mmol/m2/s) data. The relationship between Net Ecosystem Exchange (NEE) and evapotranspiration (ET) was analyzed using the coefficient of determination (R^2) and correlation coefficient (r) with the Pearson method. The results showed a relationship between NEE and ET during wet and dry periods which was in the very strong category. In diurnal wet and dry periods, the coefficient of determination (R^2) was 0.958 and 0.879, while the correlation coefficient (r) was 0.979 and 0.937. As for the diurnal wet and dry period, the coefficient of determination (R^2) is 0.923 and 0.810, while (r) is 0.962 and 0.9. The relationship
Keyword: evapotranspiration, net ecosystem exchange, palm oil, vapor pressure defici, water use efficiency

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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