Judul: Variabilitas Parameter Oseanografi Di Perairan Sekitar Kepulauan Kei Berdasarkan Data Citra Multi Sensor
Abstrak: This research aims to assess the variability of sea surface temperature (SST), chlorophyll-a concentration, and sea surface height (SSH), both spatially and temporally, in the waters around the Kei Islands. Based on monthly average wind direction, a year can be divided into four seasons, namely: Northwest season, First Transitional season, Southeast season and Second Transitional Season. The period of each season, respectively, are: December to March; April; May to October and November. The average value of monthly SST in each season are as follows: 30.460C; 30.190C; 29.320C and 30.540C, while the chlorophyll-a concentrations are as follows: 0.51; 0.59; 0.72 and 0.62 mg/m3. Period East season is the enrichment period where the average value of chlorophyll-a concentrations increased in the western part of the study area in August to 1.18 mg/m3. Enrichment of these waters due to wind pushing east into the Arafura Sea water mass Kei Islands and surrounding waters.
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Judul: Variabilitas Suhu Permukaan Laut dan Konsentrasi Klorofil-a di Samudera Hindia Bagian Timur Laut Sebelah Barat Sumatera
Abstrak: Suhu Permukaan Laut (SPL) dan konsentrasi klorofil-a merupakan parameter penting di dalam suatu perairan dan memiliki kaitan erat terhadap terjadinya fenomena oseanografi dan tingkat produktifitas. Tujuan penelitian ini adalah menganalisis variabilitas SPL dan konsentrasi klorofil-a di Sekitar Samudera Hindia bagian Timur Laut sebelah barat Sumatera. Penelitian ini menggunakan gabungan data citra NOAA-AVHRR dan MODIS untuk SPL, data citra SeaWiFS dan MODIS untuk klorofil-a, data angin permukaan bulanan diperoleh dari European Centre for Medium-Range Weather Forecasts (ECMWF). Data pendukung berupa indeks El Nino Southern Oscillation (ENSO) bulanan diperoleh dari laman https://www.ncdc.noaa.gov/teleconnections/ enso/indicators/ soi/ dan Dipole Mode Index (DMI) bulanan diperoleh dari laman https://www. jamstec.go.jp/virtualearth/general/en/index.html. Hasil penelitian menunjukkan bahwa SPL di daerah penelitian selama 22 tahun (1997–2019) berada pada kisaran 29,30 °C–31,60 °C dengan rata-rata 29,35 °C. Nilai SPL yang lebih tinggi terjadi saat Musim Barat sampai Musim Peralihan-1, sementara nilai yang lebih rendah pada Musim Timur sampai Musim Peralihan-2. Variabilitas nilai SPL dipengaruhi oleh pola angin musiman, intensitas radiasi matahari, dan Indian Ocean Dipole Mode (IODM). Saat IOD Negatif menyebabkan nilai SPL yang lebih tinggi dan konsentrasi Chl-a lebih rendah dari biasanya. Konsentrasi klorofil-a selama 22 tahun berkisar antara 0,0757 mg/m3–1,3006 mg/m3, konsentrasi klorofil-a yang lebih tinggi terjadi saat akhir Musim Timur (Agustus) dan awal Musim Barat (Desember), sementara nilai yang lebih rendah saat Musim Peralihan-1. Tingginya SPL berkisar pada Musim Peralihan-1 (Maret–Mei) bersamaan dengan rendahnya Chl-a pada musim yang sama diduga akibat terjadinya fenomena IOD negatif. Variabilitas Chl-a dipengaruhi oleh pola angin musiman, pergerakan massa air, dan IOD. Secara spasial konsentrasi Chl-a lebih tinggi didaerah pesisir dibandingkan di lepas pantai. Fenomena IOD mempengaruhi pola variasi interannual SPL dan konsentrasi Chl-a., Sea Surface Temperature (SST) and chlorophyll-a concentration are important parameters in waters that have an influence on oceanographic phenomena and oceanic productivity. The objective of this study was to analyze the variability of SST and chlorophyll-a concentration in the Northeast Indian Ocean off the West of Sumatra. The study used a combination of NOAA-AVHRR and MODIS image data for SST, SeaWiFS and MODIS image data for chlorophyll-a concenration, monthly surface wind data from the European Center for Medium Range Weather Forecasts (ECMWF). Supporting Data such as the monthly El Nino Southern Oscillation (ENSO) index and the Dipole Mode Index (DMI) were obtained from the web page of https://www.ncdc.noaa.gov/teleconnections/enso/ indicators/soi/ and https://www.jamstec.go.jp/virtualearth/general/en/index.html, respectively. The results showed that the range of SST during a 22 year period (1997–2019) was 29,30 °C–31,60 °C with the average of 29,35 °C where the higher SST occurred during the West Season and Transition Season 1, while the lower values were found during the East Season and Transition Season 2. variability of the SST values was related to the influence of seasonal winds, the intensity of solar radiation, and Indian Ocean Dipole Mode (IODM). When Negative IOD causing higher SST and lower Chl-a concentration than normal. Chlorophyll-a concentration for a 22 year perioed ranged of 0,0757-1,3006 mg/m3 where higher chlorophyll-a concentration occurred from the end of East Season (August) to the early of West Season (December), while lower values were found during Transition Season 1. The evidence of higher
Keyword: ENSO, IODM, Chlorophyll-a, Sea 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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