نتایج جستجو برای: dir psofc

تعداد نتایج: 11063  

2017
Gert Mulder Freek van Leijen

InSAR signal delays due to the varying atmospheric refractivity are a potential data source to improve weather models [1]. Especially with the launch of the new Sentinel-1 satellites, which increases data coverage, latency and accessibility, it may become possible to operationalize the assimilation of differential integrated refractivity (DIR) values in numerical weather models. Although studie...

1997
Yousong Mei Chunming Qiao

Path Multiplexing (PM) and Link Multiplexing (LM) [3, 5] are two approaches for establishing connections (or lightpaths) in optical networks. This paper describes distributed control protocols for establishing lightpaths in WDM networks using LM and PM. We propose and evaluate the performance of two classes of protocols, namely Source Initiated Reservation (SIR) and Destination Initiated Reserv...

2009
N. Choi Y. Nam

Introduction Most gray matter volumetric studies use T1-weighted imaging such as MP-RAGE because it provides good contrast between white matter and cortex. However, due to susceptibility artifact coming from the air-tissue interface (Fig. 1), a reliable and accurate measurement is difficult in the regions near the air-bone interface for T1-wieghted schemes. One way to alleviate this problem is ...

Journal: :Medical physics 2011
Tokihiro Yamamoto Sven Kabus Tobias Klinder Jens von Berg Cristian Lorenz Billy W Loo Paul J Keall

PURPOSE A novel pulmonary ventilation imaging technique based on four-dimensional (4D) CT has advantages over existing techniques and could be used for functional avoidance in radiotherapy. There are various deformable image registration (DIR) algorithms and two classes of ventilation metric that can be used for 4D-CT ventilation imaging, each yielding different images. The purpose of this stud...

2007
Clark M. Johnson Brian L. Beard Cornelis Klein Nic J. Beukes Eric E. Roden

The voluminous 2.5 Ga banded iron formations (BIFs) from the Hamersley Basin (Australia) and Transvaal Craton (South Africa) record an extensive period of Fe redox cycling. The major Fe-bearing minerals in the Hamersley–Transvaal BIFs, magnetite and siderite, did not form in Fe isotope equilibrium, but instead reflect distinct formation pathways. The near-zero average dFe values for magnetite r...

2013
K. Anbukkarasi J. Gnanambigai

Wireless Sensor Networks is an promising epitome of correlating and calculating, where a node may be self-powered and discrete node have the proficiency to intellect and interconnect. Because sensors have restricted battery power, energy efficient routing is vital. A new sensor routing scheme Q-LEACH that conglomerates the Q-DIR protocol and clustering model in LEACH protocol has been represent...

2013
Raj Varadhan Grigorios Karangelis Karthik Krishnan Susanta Hui

Quantitative validation of deformable image registration (DIR) algorithms is extremely difficult because of the complexity involved in constructing a deformable phantom that can duplicate various clinical scenarios. The purpose of this study is to describe a framework to test the accuracy of DIR based on computational modeling and evaluating using inverse consistency and other methods. Three cl...

2013
Kujtim Latifi Kenneth M. Forster Sarah E. Hoffe Thomas J. Dilling Wouter van Elmpt Andre Dekker Geoffrey G. Zhang

Ventilation imaging using 4D CT is a convenient and low-cost functional imaging methodology which might be of value in radiotherapy treatment planning to spare functional lung volumes. Deformable image registration (DIR) is needed to calculate ventilation imaging from 4D CT. This study investigates the dependence of calculated ventilation on DIR methods and ventilation algorithms. DIR of the no...

Journal: :Medical physics 2014
R Varadhan S Hui C Overbeck

PURPOSE To establish the fundamental relationship between deformation and its causative physical force using a deformable bladder phantom. To ascertain if a threshold limit exists for DIR accuracy, beyond which its applicability in deformed anatomy may be clinically inappropriate. METHODS A tissue equivalent deformable bladder phantom with 21 implanted aluminum markers was developed using a v...

2015
Y G Roussakis H Dehghani S Green G J Webster

OBJECTIVE Dose warping following deformable image registration (DIR) has been proposed for interfractional dose accumulation. Robust evaluation workflows are vital to clinically implement such procedures. This study demonstrates such a workflow and quantifies the accuracy of a commercial DIR algorithm for this purpose under clinically realistic scenarios. METHODS 12 head and neck (H&N) patien...

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