排序方式： 共有17条查询结果，搜索用时 31 毫秒
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Thomas Mathai M. Suresh Chandran S. B. Nair M. R. Asoka Kumar Satish Kumar P. Praveen Kumar 《Marine Georesources & Geotechnology》2013,31(3-4):151-165
Sediment core samples collected during geotechnical surveys along the West Coast of India in the near shore areas of Arabian Sea have generated data on the geotechnical index properties of clayey sediments up to nearly 5 m depth below seafloor. A comparative study of three sectors within themselves is attempted before carrying out a final evaluation between the sectors. Cohesive clayey sediments of Gujarat sector are comparable though widely variant in a few aspects; in the Maharashtra-Goa-Karnataka sector though, plasticity levels and clay type vary, and activity and consistency levels are quite similar. Though broadly comparable, the clayey sediments of Kerala-Tamilnadu sector have quite diverse characteristics that fail to conform to any particular pattern as each area has an exclusive set of geotechnical properties. 相似文献
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Vembanad lake system (VLS) is a Ramsar wetland of premier importance along the south west coast of India. This system spread over 13098 km2 accounts for 33.7% of total geographic area of Kerala state. VLS sustains by the input of six main river systems of Kerala viz., Achankovil, Pampa, Manimala, Meenachil, Muvattupuzha and Periyar. Central focus of this study is to find out the influence of morphometric variables on hydrological processes using geo-informatics and correlation analysis and to analyse the scale dependence of basin hypsometry in steady state topography and hydrology. The study also examines the contribution of each river in making the entities of this wetland system by portraying the morphometric and hypsometric parameters of its watershed. The results of this analysis reveals that the Manimala river basin has survived with rapid denudation activities and run off mechanism, while Periyar and Pampa river basins have culminating stage of development and are tectonically active. This study immensely contributes to the knowledge on the influence of morphometric variables on hydrological process and scale dependence of basin hypsometry in steady state topography including hydrology of VLS. The results will shed some light on hydrologic makeup of inflow rivers and will be beneficial for the sustainable management of India’s one of the premier wetlands. 相似文献
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Benjamin D.G. Chandran 《Astrophysics and Space Science》2004,292(1-4):17-28
This brief review provides an introduction to key ideas in the theory of incompressible magnetohydrodynamic (MHD) turbulence. 相似文献
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A. Chandran D.W. Rusch S.E. Palo G.E. Thomas M.J. Taylor 《Journal of Atmospheric and Solar》2009,71(3-4):392-400
We present the first results of gravity wave signatures on polar mesospheric clouds (PMCs) during the summer of 2007, in the northern hemisphere polar region. The Cloud Imaging and Particle Size (CIPS) experiment has one of the three instruments on board the NASA Aeronomy of Ice in the Mesosphere (AIM) spacecraft, which was launched into a sun-synchronous orbit on April 25, 2007. CIPS is a four-camera, wide-field (120°×80°) imager designed to measure PMC morphology and particle properties. One of the objectives of AIM is to investigate gravity wave effects on PMC formation and evolution. CIPS images show distinct wave patterns and structures in PMCs that are similar to ground-based photographs of noctilucent clouds (NLCs). The observed horizontal wavelengths of the waves were found to vary between 15 and 320 km, with smaller-wavelength structures of less than 50 km being the most common. In this paper we present examples of individual quasi-monochromatic wave events observed by CIPS and statistics on the wave patterns observed in the northern hemisphere during the summer months of 2007, together with a map showing the geographic locations of gravity wave events observed from CIPS. 相似文献
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A numerical study on an approach based on the time-frequency analysis is performed for the high-resolution direction finding applications of wide-band signals. In this method, the direction of arrival (DOA) is estimated using a subband of the incoming signal instead of the whole signal spectrum. This treatment forces the DOA of the wide-band signals to be similar to that of the DOA of the narrow-band signals. The reason behind this can be thought of as the after effects of reducing the signal bandwidth, which constrains the signal subspace. An empirical analysis of the performance of the DOA estimator Is also investigated. This is done to compare the correct and estimated angles of separation between the targets, and it is demonstrated that there is a good agreement which implies that the use of prefiltering does not affect the resolution of the DOA estimator 相似文献
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Akshara Preethy Byju Anil Kumar Alfred Stein A. Senthil Kumar 《Journal of the Indian Society of Remote Sensing》2018,46(9):1519-1526
This article presents the use of kernel functions in fuzzy classifiers for an efficient land use/land cover mapping. It focuses on handling mixed pixels obtained from a remote sensing image by considering non-linearity between class boundaries. It uses kernel functions combined with the conventional fuzzy c-means (FCM) classifier. Kernel-based fuzzy c-mean classifiers were applied to classify AWiFS and LISS-III images from Resourcesat-1 and Resourcesat-2 satellites. Optimal kernels were obtained from eight single kernel functions. Fractional images generated from high resolution LISS-IV image were used as reference data. Classification accuracy of the FCM classifier increased with 12.93%. Improvement in overall accuracy shows that non-linearity in the dataset was handled adequately. The inverse multiquadratic kernel and the Gaussian kernel with the Euclidean norm were identified as optimal kernels. The study showed that overall classification accuracy of the FCM classifier improved if kernel functions were included. 相似文献