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Iyyappan Muthukumarasamy Ramakrishnan S. Shanmugam Srinivasa Raju Kolanuvada 《Environmental Earth Sciences》2017,76(13):455
Synthetic aperture radar (SAR) has operational applications in crop mapping and monitoring in many countries due to the distinct backscatter signature at various stages of crop growth. Polarimetric analysis of SAR data from different satellites was used for information extraction from different types of scatters in imaged terrain. The scattering processes were analyzed through the received scatter matrix derived from the target decomposition of SAR data. Three decomposition techniques, namely Freeman–Durden, Cloude–Pottier and Touzi decomposition of the ALOS PALSAR-1 data, were used in this study to extract land use/cover information with a specific emphasis on agriculture. The decomposed output parameters from these techniques were classified with supervised classifier of support vector machine (SVM) using region of interest (ROI) selected land use/cover classes. An accuracy assessment for the classified output was carried out using the ROI. The Ramgarh village in Jaisalmer district of Rajasthan with the predominance of agricultural land, sand dunes and settlements was chosen as the study area. Freeman–Durden decomposition resulted in the highest overall accuracy of about 85% in the land use/cover classification among the three decomposition techniques adopted in the study. It was also observed that the accuracy of land use/cover mapping derived from Cloude–Pottier and Touzi decompositions improved with the use of eigenvalues in the SVM classification. Higher accuracies in the classification of agriculture land were noted with all the three decomposition techniques. The four parameters of Cloude–Pottier (H, A, α, β) and Touzi (α s, Φ s, ψ, τ) decompositions improved the classification accuracy for all the classes due to eigenvalues. The overall classification accuracy was above 88% for both the decomposition techniques with four parameters. The soil moisture values for agriculture land and sand dunes were validated through soil moisture maps generated using Oh 1992 and 2004 models. 相似文献
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Boby Ignatius Muthukumarasamy Srinivasan Srinivasan Balakrishnan 《Ocean Science Journal》2011,46(3):145-154
The sandbird octopus Amphioctopus aegina (Gray, 1849) is one of the important octopod species in trawl catches in Mandapam waters (Palk Bay). The reproductive biology
of this species from these waters was studied from October 2001 to September 2002. In the majority of months(Jan–June), the
sex ratio was biased towards males. The ratios of males to females increased consistently with respect to weight Total weight
at first maturity were 78.78g for females and 40.8 g for males. Four maturity stags were recognized for females and two for
males. Maturation and spawning occur all year round, with a peak during October and another peak during January–February.
In males, no definite seasonal changes were observed in gonadosomatic index (GSI) values. In females there were two peaks
in GSI values during October and January–February. For individuals of a DML range of 67–85 mm fecundity varied between 2,962–8,820
oocytes. The average relative fecundity was estimated at 68 to 83 and the average number oocytes per gram of ovary were 488
to 539. 相似文献
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