نتایج جستجو برای: given tec time series

تعداد نتایج: 2577805  

Journal: :مدیریت مخاطرات محیطی 0
فریده سبزه ای کارشناس ارشد ژئودزی - هیدروگرافی گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران محمدعلی شریفی دانشیار، گروه مهندسی نقشه برداری و پژوهشکده مهندسی فناوری های اطلاعات مکانی، پردیس دانشکده های فنی دانشگاه تهران، ایران مهدی آخوندزاده استادیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران

earthquakes show unknown nonlinear behavior and given the magnitude of the earthquake, we would encounter certain changes in lithosphere, atmosphere and ionosphere. the ionospheric parameters have been found to be sorely susceptible to major earthquakes. in addition to the ionospheric variations generated by solar activity, there are remarkable temporary changes in the ionosphere that are gener...

ژورنال: ژئوفیزیک ایران 2015
Farideh Sabzehee Mohammad Ali Sharifi Saeed Farzaneh

The Total Electron Content (TEC) measured by the Global Positioning System (GPS) is useful for registering the pre-earthquake ionospheric anomalies appearing before a large earthquake. In this paper the TEC value was predicted using the singular value thresholding (SVT) method. Also, the anomaly is detected utilizing this predicted value and the definition of the threshold value, leading to the...

Journal: :فیزیک زمین و فضا 0
جمال عسگری استادیار، گروه مهندسی نقشه برداری، دانشکده فنی و مهندسی، دانشگاه اصفهان، ایران علیرضا امیری سیمکویی استادیار، گروه مهندسی نقشه برداری، دانشکده فنی و مهندسی، دانشگاه اصفهان، ایران

the least squares harmonic estimation is applied to the hourly time-series of total electron contents (tec) derived from ionospheric models using seven years of gps observations processed by bernese software. the frequencies of dominant spectral components in the spectrum are estimated. we observe significant periodic patterns with periods of 24 h and its fractions 24h/n, n=2,…,11, which are th...

2017
Giorgio Savastano Attila Komjathy Olga Verkhoglyadova Augusto Mazzoni Mattia Crespi Yong Wei Anthony J. Mannucci

It is well known that tsunamis can produce gravity waves that propagate up to the ionosphere generating disturbed electron densities in the E and F regions. These ionospheric disturbances can be studied in detail using ionospheric total electron content (TEC) measurements collected by continuously operating ground-based receivers from the Global Navigation Satellite Systems (GNSS). Here, we pre...

2014
Jingbin Liu Ruizhi Chen Zemin Wang Jiachun An Juha Hyyppä

Knowledge of the polar ionospheric total electron content (TEC) and its future variations is of scientific and engineering relevance. In this study, a new method is developed to predict Arctic mean TEC on the scale of a solar cycle using previous data covering 14 years. The Arctic TEC is derived from global positioning system measurements using the spherical cap harmonic analysis mapping method...

2012
J. N. Thomas J. J. Love A. Komjathy O. P. Verkhoglyadova M. Butala N. Rivera

[1] Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (TEC) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting earthquakes. On the other hand, and in a s...

1998
R. Pisani

Time Expansion Chamber (TEC) will perform both particle identi cation and tracking functions in the PHENIX experiment. For the evaluation of the TEC performance, optimization of tracking and particle identi cation algorithms, and early development of o -line analysis software, detailed simulations are necessary. A Slow Simulator for PHENIX TEC (TECSS) was created for this purpose. The Simulator...

Global positioning system (GPS) measurements provide accurate and continuous 3-dimensional position, velocity and time data anywhere on or above the surface of the earth, anytime, and in all weather conditions. However, the predominant ranging error source for GPS signals is an ionospheric error. The ionosphere is the region of the atmosphere from about 60 km to more than 1500 km above the eart...

M. Fallah ‎Jelodar, M. Sanei S. Mamizadeh-‎Chatghayeh‎

The performance of a supply chain can be evaluated in either a cross-sectional or a time series manner, and data envelopment analysis is a useful method for both types of evaluation. In this paper we develop an index and indicator of productivity change that can be used with radial and non-radial models for supply chain malmquist index. The supply chain malmquist productivity index (SCMPI) can ...

Journal: :international journal of industrial mathematics 2015
m. fallah ‎jelodar m. sanei s. mamizadeh-‎chatghayeh‎

the performance of a supply chain can be evaluated in either a cross-sectional or a time series manner, and data envelopment analysis is a useful method for both types of evaluation. in this paper we develop an index and indicator of productivity change that can be used with radial and non-radial models for supply chain malmquist index. the supply chain malmquist productivity index (scmpi) can ...

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