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11.
A national level project on kharif rice identification and acreage estimation is being carried out successfully for several states in the country. A similar
methodology based on the temporal profile for identification and delineation of various land cover classes has been followed
for the Rabi rice acreage estimation. To define rabi rice, rabi season in India starts from November — February to March — June. Though the main growing season is predominantly winter but
the uncertainty of getting cloud free data during the season has resulted in the use of microwave data. A feasibility study
was taken up for early forecasting of the rabi rice area using microwave data. Hierarchical decision rule classification technique was used for the identification of the
different land cover classes. Land preparation, puddling and transplantation were the reasons for the specific backscatter
of rice growing areas. The increase or decrease in the SAR backscatter due to progress in the crop phenology or due to delayed
sowing respectively forms the basis for identifying the rice areas. In addition the potential of optical data of a later date
has been utilized in the form of various indices from bands including MIR to distinctly separate the late sown areas and also
the puddled areas from other areas. This study emphasizes the synergistic use of SAR and optical data for delineating the
rabi rice areas which is of immense use in giving an early forecast. 相似文献
12.
In recent years, the thermodynamic properties of black holes are topics of interests. We investigate the thermodynamic properties like surface gravity and Hawking temperature on event horizon of regular black holes viz. Hayward Class and asymptotically AdS (Anti-de Sitter) black holes. We also analyze the thermodynamic volume and naive geometric volume of asymptotically AdS black holes and show that the entropy of these black holes is simply the ratio of the naive geometric volume to thermodynamic volume. We plot the different graphs and interpret them physically. We derive the ‘cosmic-Censorship-Inequality’ for both type of black holes. Moreover, we calculate the thermal heat capacity of aforesaid black holes and study their stabilities in different regimes. Finally, we compute the logarithmic correction to the entropy for both the black holes considering the quantum fluctuations around the thermal equilibrium and study the corresponding thermodynamics. 相似文献
13.
Syam S. De Barin K. De Goutami Chattopadhyay Suman Paul Dilip K. Haldar Dipak K. Chakrabarty 《Acta Geophysica》2011,59(2):361-376
Autoregressive neural network (AR-NN) models of various orders have been generated in this work for the daily total ozone
(TO) time series over Kolkata (22.56°N, 88.5°E). Artificial neural network in the form of multilayer perceptron (MLP) is implemented
in order to generate the AR-NN models of orders varying from 1 to 13. An extensive variable selection method through multiple
linear regression (MLR) is implemented while developing the AR-NNs. The MLPs are characterized by sigmoid non-linearity. The
optimum size of the hidden layer is identified in each model and prediction are produced by validating it over the test cases
using the coefficient of determination (R
2) and Willmott’s index (WI). It is observed that AR-NN model of order 7 having 6 nodes in the hidden layer has maximum prediction
capacity. It is further observed that any increase in the orders of AR-NN leads to less accurate prediction. 相似文献
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Gravity-controlled and other sedimentary structures exhibited by the ultramafic rocks of Nausahi, Keonjhar District, Orissa, India, are described and their significance briefly discussed. Mineral-graded and size-graded layering, slump structure and cusp textures formed by the influence of gravity, indicate that the ultramafic rocks under study have not been overturned and that the original depositional floor had a gentle north-easterly slope. The magmatic currents were locally strong enough to give rise to some characteristic structures like small-scale angular discordance, branching of chromite lamina, inclusion of one rock type in another, etc. There are also some structures resembling ripple mark and load cast. The pyroxenite dykes and veins were intruded predominantly in the solid state into the dunite-chromitite associations. 相似文献
16.
Development of rational models for tunnel blast prediction based on a parametric study 总被引：2，自引：0，他引：2
A. K. Chakraborty A. K. Raina M. Ramulu P. B. Choudhury A. Haldar P. Sahoo C. Bandopadhyay 《Geotechnical and Geological Engineering》2004,22(4):477-496
The empirical models available for prediction of the tunnel blast results like pull ratio, specific charge, specific drilling and overbreak have some inherent shortcoming in absence of any parametric study at the backdrop. Hence, the models use different constituting parameters and provide values which differ widely. After a thorough review of literature and field investigations in the drivages of mines and tunnels some parameters were identified. Those parameters were subjected to Multiple Linear Regression analyses to filter out the most influencing ones which represent the rockmass properties, the tunnel configurations and the blast designs. A parameter called Tunnel Blasting Index (TBI) was conceptualized and was expressed in terms of those most influencing parameters. All the blast results observed during the filed investigations could be well related to a single index TBI. Some adjustments on account of shape of the tunnel and joint orientations, which were not addressed in the available models, are suggested in the developed models. 相似文献
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Syam Sundar De B. K. De B. Bandyopadhyay B. K. Sarkar Suman Paul D. K. Haldar S. Barui Asim Datta Syam Sundar Paul Nikhilesh Paul 《Pure and Applied Geophysics》2010,167(10):1273-1279
Several experiments were undertaken at Kolkata (latitude: 22°34′N, longitude: 88°30′E) on the solar eclipse day of August 1, 2008 to observe the effects of the solar eclipse on Fair Weather Field (FWF) and VLF amplitude and phase. The experimental results presented here show significant deviations of the observed parameters from their normal values, as they are determined by the average of the records obtained on 5 days adjacent to the day of the solar eclipse. 相似文献
19.
Yaduvanshi Aradhana Kulkarni Ashwini Bendapudi Ramkumar Haldar Kaushik 《Natural Hazards》2020,103(1):685-711
Natural Hazards - The present study examines the spatial and temporal changes in extreme rainfall events (EREs) across the Godavari river basin to develop adaptation strategies for vulnerable... 相似文献
20.
Hamoon Azizsoltani J. Ramon Gaxiola-Camacho Achintya Haldar 《Bulletin of Earthquake Engineering》2018,16(9):3819-3843
Designing more seismic load-tolerant structures is one of the major challenges of the world communities. It is due to the inability of the profession to predict future design earthquake time histories at a site compounded by the failure to appropriately incorporate uncertainties in other design variables and structural behavior just before failure. A site-specific method is proposed to generate a suite of ground excitation time histories and a novel risk estimation is developed considering major sources of nonlinearity and uncertainty. For wider application and acceptance, the risk evaluation procedure essentially consists of few deterministic time domain finite element analyses. The procedure is verified and showcased by estimating risks associated with three buildings designed by professional experts in the Los Angeles area satisfying the post-Northridge design criteria for the overall lateral deflection and inter-story drift. The accuracy of the estimated risk is verified using the Monte Carlo simulation technique. In all cases, the probabilities of collapse are found to satisfy the current code requirements. The spread in the reliability indexes for each building for both limit states cannot be overlooked, indicating the significance of the frequency contents of the time histories. The inter-story drift is found to be more critical than the overall lateral displacement. The reliability indexes for both limit states are similar only for few cases. The authors believe that they proposed an alternative to the classical random vibration and simulation approaches. The proposed site-specific seismic safety assessment procedure can be used by practicing engineers for routine applications. 相似文献