Judul: Analisis Temporal Vegetation Health Index (VHI) untuk Kekeringan Lahan Persawahan. Studi Kasus Kabupaten Indramayu, Jawa Barat
Abstrak: Agricultural drought related to determine of water table so can’t be able to fill crop necessary. Agricultural drought can be analyzed by using an index based on the condition of vegetation (Vegetation Health Index (VHI)). The purpose of this research to analyze the drought index fields using the VHI in the dry months (JJAS) with Kogan method, suspect the relationship between TCI with elements of the climate, as well as to analysis the relationship between VHI and rice productivity. VHI is obtained by Temperature Condition Index (TCI) and Vegetation Condition Index (VCI) which will be corelated with climate data (temperature and precipitation) while VHI by extensive data drought. Indramayu district have characteristic to average precipitation month revolve 0- 358 mm and temperature of average month 260C-28.30C. District Krangkeng, Kandanghaur, Indramayu and Karangampel have the langest sensivity of drought in period 2009-2013. Percentage of VHI index is quite high with a high incidence of drought, happened in July and August as well as with temporal in 2012. Results of TCI index has determinant coefficient (R2) of 0.230 with rainfall and 0.117 with the air temperature. Based on percentage VHI (<=40), drought factors can affect the productivity of rice. The lowest productivity, districts Krangkeng, Kandanghaur and Karangampel in 2010 and in 2012 for Indramayu district.
Keyword: Rice Productivity., VCI, TCI, VHI, Agricultural drought

Judul: Analysis of Meteorological and Agricultural Drought Rate of Rice Field on Java Island Using SPI and VHI
Abstrak: Pulau Jawa memiliki iklim tropis dengan tanah yang di dominasi dataran rendah sehingga memiliki potensi untuk budidaya tanamanan padi. Kekurangan air pada tanaman padi dapat menyebabkan berkurangnya produktivitas padi. Penelitian bertujuan untuk mengindentifikasi sebaran spasial dan kategori kekeringan meteorologi dan pertanian pada tahun normal, El Nino kuat, dan El Nino lemah. Penelitian dilaksanakan menggunakan teknologi cloud computing, yakni Google Earth Engine dengan melihat sejumlah citra satelit MODIS melalui band Enhance Vegetation Index (EVI) dan Land Surface Temperature (LST) serta data curah hujan CHIRPS. EVI dan LST kemudian diolah menjadi Vegetation Health Index (VHI) sementara data CHIRPS diolah menjadi data SPI-1. SPI-1 menunjukan distribusi kekeringan meteorologi di Jawa pada 4 periode musim, dengan periode SON (September-Oktober-November) memiliki nilai SPI-1 terendah mencapai - 1,05 termasuk dalam kategori kekeringan sedang. VHI menunjukan distribusi kekeringan pertanian di Jawa juga pada 4 periode musim, dengan periode SON memiliki nilai VHI terendah dalam rentang 10 hingga 20 termasuk dalam kategori kekeringan kuat., Java island has a tropical climate with low-land dominated all around so is potential for rice cultivation. Water deficiency of rice plants will cause lower rice productivity. This research aims to identify spatial distribution and drought categories of meteorological and agricultural when normal year, strong El Nino year, and weak El Nino year. Research conducted by uses of cloud computing technology, that is Google Earth Engine to see a number of MODIS satellite imagery at Enhance Vegetation Index (EVI) band and Land Surface Temperature (LST) band and CHIRPS precipitation data. EVI and LST than process to be Vegetation Health Index (VHI) while CHIRPS data process to be SPI-1. SPI-1 show meteorological drought distribution on Java in 4 seasons period, there is SON (September-October-November) has lowest SPI-1 value by -1,05 in intermediate drought category. VHI show agriculture drought distribution on Java so in 4 seasons period, there is SON has lowest VHI value by range 10 to 20 in strong drought category.
Keyword: Drought, El Nino, SPI, VHI

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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