نتایج جستجو برای: offset data while prestack time migration applies to unstacked data

تعداد نتایج: 11262398  

2003
William W. Symes Christiaan C. Stolk Fuchun Gao

Shot-geophone migration, commonly accomplished using wavefield depth extrapolation (“survey sinking”), has a two way reverse time realization as well. The reverse time version permits imaging of overturned reflections. Shot-geophone migration differs from other prestack migrations in the definition of the prestack image volume which it creates. This difference is most clearly seen by identifyin...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم انسانی 1390

this study attempted to explore if teaching english collocations through two different modes of awareness-raising and input flooding has any possible differential effect on immediate retention as well as retention in a delayed assessment. it also compared the possible differential effect of teaching english collocations implicitly and explicitly on actively using the items in writing. m...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اصفهان - دانشکده زبانهای خارجی 1389

this study was conducted to investigate the impact of portfolio assessment as a process-oriented assessment mechanism on iranian efl students’ english writing and its subskills of focus, elaboration, organization, conventions, and vocabulary. out of ninety juniors majoring in english literature and translation at the university of isfahan, sixty one of them who were at the same level of writing...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده علوم انسانی 1391

the present study sought to investigate the impact of using mind-mapping technique instruction on female elementary efl learners reading comprehension; it also investigated their attitudes towards using mind-mapping technique as a tool to improve their reading comprehension. this study followed a quasi-experimental design with two intact groups as experimental, and control groups. the participa...

2011
CHRISTIAAN C. STOLK MAARTEN V. DE HOOP WILLIAM W. SYMES

Recent analysis and synthetic examples have shown that many prestack depth migration methods produce non-flat image gathers containing spurious events, even when provided with a kinematically correct migration velocity field, if this velocity field is highly refractive. This pathology occurs in all migration methods which produce partial images as independent migrations of data bins. Shot-geoph...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1392

the present study seeks to determine the effect of explicit instruction of metacognitive strategies on iranian high school students’ reading comprehension ability. it also attempts to investigate the relationship between the learners reading comprehension and metacognitive strategies. furthermore, the study investigates whether iranian efl female high school students are high, medium, or low me...

2005
Christiaan C. Stolk Maarten V. de Hoop William W. Symes

In contrast to prestack migration methods based on data binning, common image gathers produced by shot-geophone migration exhibit the appropriate semblance property in either offset domain (focussing at zero offset) or angle domain (focussing at zero slope), when the migration velocity is kinematically correct and when events to be migrated arrive in the data along non-turning rays. The latter ...

2002
Jianhua Yu

Reflection amplitude as a function of offset is effective in characterizing lithology in oil producing basins. Experience shows that AVO inversion methods based on amplitude-preserved prestack migration typically provides a more accurate lithology estimation than NMO-based AVO analysis. However, some artifacts may be introduced into the migration section, which can obscure the estimate of reser...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد گرمسار - دانشکده زبانهای خارجی 1389

previous studies have aimed at testing a hypothesis but the present study is data-first research in which researcher tries to form a theory from data rather than the use of data to test a hypothesis. this study aims at exploring teachers perceptions of the strengths and weaknesses of the current syllabus for college preparatory course. eight experienced teachers were selected to collect data du...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم انسانی 1389

abstract the present research is prepared to study the culture of tea consuming among iranian. the case group which was statistically used for this study was people of lahijan , about four hundred wich were chosen according to their age , gender , education and occupation , randomly selected to fill the questionnaire . then the data collected through the questionnaire was analyzed according ...

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