نتایج جستجو برای: local expand of meanders

تعداد نتایج: 21211281  

Journal: :پژوهش های جغرافیای طبیعی 0
مهران مقصودی استادیار دانشکده جغرافیا، دانشگاه تهران حمید کامرانی دلیر دانشجوی کارشناسی ارشد، دانشگاه تهران

the tajan river is one of the most important rivers in the north of iran. it seems that in respect of its meander design and pattern, passing over the block's fault and deviations along its way, it's influenced with active neotectonically movements in the region. although being meander in rivers, in the level of a flood water field with very low gradient, isn't unexpected but exi...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1391

efl/esl textbooks have been regarded as essential language teaching materials with which the learners spend about 70 up to 90 percent of their class time. the important role they play and their vast use make them not only influential in learning the language but also in shaping values and attitudes. put it another way, textbooks socialize learners using their contents (i.e. texts, illustrations...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران - دانشکده علوم 1380

هدف این پایان نامه تعیین تعداد مولدهای مینیمال ایده آلها در یک حلقه (جابجایی، یکدار، موضعی و نوتری) است، هر چند تعیین دقیق تعداد مولدها در حالتهایی خاص امکان پذیر است اما در حالتهای کلی روش های موجود بدست آوردن کرانهای مختلف برای تعداد مولدها است. مرجع اصلی این پایانامه ‏‎[1]‎‏ می باشد، به علاوه از نتایج جدیدی که در مرجع ‏‎‏‎[2]‎‏ نیز آمده استفاده کرده ایم. ‏‎[1]. j. sally. numbers of generator...

1999
Iwan Jensen

A closed plane meander of order n is a closed self-avoiding loop intersecting an infinite line 2n times. Meanders are considered distinct up to any smooth deformation leaving the line fixed. We have developed an improved algorithm, based on transfer matrix methods, for the enumeration of plane meanders. This allows us to calculate the number of closed meanders up to n = 24. The algorithm is eas...

Journal: :تحقیقات جغرافیایی 0
نجمه نجمی گروه جغرافیای طبیعی دانشگاه اصفهان عبدالله سیف گروه جغرافیای طبیعی دانشگاه اصفهان

karun river with a length of about 890 km is considered as a main river in the country. in this paper, types of karun’s screws regarding to the geometric factors of radius of curvature and chord length were identified by fitting circles with the arcs of the river’s axis. river’s arcs were classified into simple and compound screws. then, by formation of the database consist of topographic...

1999
STEPHAN D. HOWDEN D. RANDOLPH WATTS

Mesoscale alongstream speed changes of the Gulf Stream are diagnosed from an array of current meters at depths 400, 700, and 1000 m, near 688W, during the development of steep [ratio of ‘‘amplitude’’ to ‘‘wavelength’’ O(1)] meanders. Speed maxima (jet streaks) are generally found between trough and crest axes in steep meanders with local speed minima near the trough and crest axes. Speed change...

2000
Iwan Jensen

A closed plane meander of order n is a closed self-avoiding curve intersecting an infinite line 2n times. Meanders are considered distinct up to any smooth deformation leaving the line fixed. We have developed an improved algorithm, based on transfer matrix methods, for the enumeration of plane meanders. While the algorithm has exponential complexity, its rate of growth is much smaller than tha...

2008
J. Sawada R. Li

By considering a permutation representation for meanders, semi-meanders, and stamp foldings we construct a new data structure that will allow us to extend the order of a given meander, semi-meander, or stamp folding in constant time. Then using this data structure, we develop a constant amortized time algorithm to generate all semi-meanders of order n. By maintaining the wind-factor for semi-me...

2008
E. A. Addink M. G. Kleinhans

The long-term discharge evolution of branches of rivers can potentially be derived from inactive and fossil river meanders using relations between discharge and channel width and meander dimensions. This evolution is relevant for the understanding of river dynamics and avulsion, and the resulting changes of downstream flooding risks and shipping conveyance. Unfortunately, digitalisation of infi...

2000
Iwan Jensen Anthony J. Guttmann

Meanders form a set of combinatorial problems concerned with the enumeration of self-avoiding loops crossing a line through a given number of points, n. Meanders are considered distinct up to any smooth deformation leaving the line fixed. We use a recently developed algorithm, based on transfer matrix methods, to enumerate plane meanders. This allows us to calculate the number of closed meander...

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