Hossam Mohammmad Hassan Abdelwahab <br/><br/>
On censoredand missing observationsin nonstationary time series /  
 حول القيم المفقودة و المراقبة للسلاسل الزمنية الغير مستقرة 
Hossam Mohammmad Hassan Abdelwahab ; Supervised Eid H. Doha , Abdel H. Elshaarawi 
 - Cairo :   Hossam Mohammmad Hassan Abdelwahab ,   2021 
 - 83 P. :   charts ;   25cm  
<br/><br/>Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Mathematics 
<br/><br/> Exposure to toxic contaminants in the environment harm human and an- imal health as well as disturb the integrity and function of the impacted ecosystem.The impact could belocal ,regional ,and global.The concen- tration  of a toxic substance below or above detection limits or thresholds in environmental samples is frequently recorded as non-detect ,which cre- ate a left or right censoring .Interval censoring occurs when the correct values are known only for those falling above a lower threshold and below an upper threshold.Multiple censored points are also important in prac- tice, as censoring threshold values may change overtime .In this thesis, we aim to estimate the environmental contaminants concentration and loading in the presence of censored and missing value  
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<br/><br/><label>Subjects--Index Terms: </label>Censoredand missing Maximum likelihood estimates  Nonstationary Time Series