Results 131 to 140 of about 950 (162)
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Journal of Atmospheric and Terrestrial Physics, 1978
Abstract The simulations of trough ionograms by Lobb and Titheridge (1977) are supplemented by calculating a trace caused by rays having a double oblique reflection in the ionosphere and not retracing their paths. It is also shown how the different parts of the traces are caused by echoes of different types.
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Abstract The simulations of trough ionograms by Lobb and Titheridge (1977) are supplemented by calculating a trace caused by rays having a double oblique reflection in the ionosphere and not retracing their paths. It is also shown how the different parts of the traces are caused by echoes of different types.
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Lossless compression of ionogram data
Proceedings of 13th International Conference on Digital Signal Processing, 2002A method for lossless compression of binary data is presented. To remove the redundancies among the data points, a linear predictive scheme is proposed and the coefficients are optimised in the sense of minimum mean square error. An arithmetic coder is then used to code the prediction errors.
null Hua Ye +2 more
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2017
This chapter explores how the Alouette satellite’s reorientation of global data flows and mass-production of ionograms altered the natural order at the core of DRTE’s research. The satellite’s unexpected reliability demanded an automated system of data analysis.
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This chapter explores how the Alouette satellite’s reorientation of global data flows and mass-production of ionograms altered the natural order at the core of DRTE’s research. The satellite’s unexpected reliability demanded an automated system of data analysis.
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Journal of Atmospheric and Terrestrial Physics, 1970
Abstract Spread- F echoes are not due to partial reflection from small irregularities. Rather they are due to total reflection from large tilted surfaces of ionization. The geometry of these surfaces is examined using ionograms and airglow observations, together with Australian experiments reported in the literature.
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Abstract Spread- F echoes are not due to partial reflection from small irregularities. Rather they are due to total reflection from large tilted surfaces of ionization. The geometry of these surfaces is examined using ionograms and airglow observations, together with Australian experiments reported in the literature.
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Ionograms denoising via curvelet transform
Advances in Space Research, 2013Abstract Ionograms are used to obtain important information of the ionosphere. Unfortunately, ionograms are always contaminated by several kinds of noises. In this paper, curvelet transform denoising algorithm is used to obtain high-quality ionograms.
Ziwei Chen +3 more
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Serum ionogram in heperpyrexia
The Indian Journal of Pediatrics, 1960Forty-five consecutive cases of pyrexia with temperatures above 103oF occurring in children ranging from one to twelve years of age were studied clinically and for serum electrolyte changes.
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Neural networks for several ionogram features
Radio Science, 1995Several demonstration neural networks will be described that identify certain characteristics of ionograms. The characteristics identified are ordinary and extraordinary F region critical frequency, F1 cusp frequency, sporadic E type C and type H cusp frequencies, and spread F. Accuracy for the neural networks varies, ranging from 50% to 90%.
J. N. Hill, T. H. Koschmieder
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Automatic scaling of digital ionograms
Radio Science, 1989A new system has been devised to automatically scale digital ordinary‐ray ionograms. The system has been developed for use at mid‐latitudes and has been trained on a full set of ionograms that are typical of the region. This paper describes the stages adopted in forming, recognizing, and scaling traces from the various ionospheric layers.
Matthew W. Fox, Craig Blundell
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Classification of spread-F ionograms
Journal of Atmospheric and Terrestrial Physics, 1962Abstract Scaling of original ionograms obtained in the polar regions has lead to a classification scheme for spread-F ionograms. Defined are three types of frequency spreading (spreadish-F, furcated-F and spurred-F) and one type of range spreading. Each type is subdivided into species.
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Ionogram inversion using NeQuick2 model
2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), 2014NeQuick2 is a well-known ionospheric model for electron density computation, utilizing the Epstein layer formulation originally proposed by G. Di Giovanni and S.M. Radicella. In this study, algorithm of NeQuick2 model has been employed for ionogram inversion using MATLAB.
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