Searched for: collection%253Air
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Hedayati, R. (author), Yousefi, Armin (author), Dezaki, Mohammadreza Lalegani (author), Bodaghi, Mahdi (author)
Both 2D and 3D re-entrant designs are among the well-known prevalent auxetic structures exhibiting negative Poisson's ratio. The present study introduces novel analytical relationships for 2D re-entrant hexagonal honeycombs for both negative and positive ranges of the cell interior angle θ (θ<0 showing a negative Poisson's ratio). The...
journal article 2023
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Hedayati, R. (author), Yousefi, Armin (author), Bodaghi, Mahdi (author)
With dramatic increase in 3D printing applications in industry, sandwich panels with 3D printed cores have gained a lot of attention recently. In harmony with global movement towards sustainability and low-carbon emission industries, sandwich panels with easy-to-repair and cost-effective cores would be very attractive structures. In this...
journal article 2022
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Brink, Wyger M. (author), Yousefi, Sahar (author), Bhatnagar, Prernna (author), Remis, R.F. (author), Staring, M. (author), Webb, A. (author)
Purpose: Parallel RF transmission (PTx) is one of the key technologies enabling high quality imaging at ultra-high fields (≥7T). Compliance with regulatory limits on the local specific absorption rate (SAR) typically involves over-conservative safety margins to account for intersubject variability, which negatively affect the utilization of...
journal article 2022
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Yousefi, Sahar (author), Sokooti, Hessam (author), Elmahdy, Mohamed S. (author), Lips, Irene M. (author), Shalmani, Mohammad T.Manzuri (author), Zinkstok, Roel T. (author), Dankers, Frank J.W.M. (author), Staring, M. (author)
Manual or automatic delineation of the esophageal tumor in CT images is known to be very challenging. This is due to the low contrast between the tumor and adjacent tissues, the anatomical variation of the esophagus, as well as the occasional presence of foreign bodies (e.g. feeding tubes). Physicians therefore usually exploit additional...
journal article 2021
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Yousefi, Armin (author), Serjouei, Ahmad (author), Hedayati, R. (author), Bodaghi, Mahdi (author)
In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum al-loy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a...
journal article 2021
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Yousefi, Armin (author), Jolaiy, Saman (author), Hedayati, R. (author), Serjouei, Ahmad (author), Bodaghi, Mahdi (author)
Bonded patches are widely used in several industry sectors for repairing damaged plates, cracks in metallic structures, and reinforcement of damaged structures. Composite patches have optimal properties such as high strength‐to‐weight ratio, easiness in being applied, and high flexibility. Due to recent rapid growth in the aerospace industry,...
journal article 2021
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Sokooti, Hessam (author), Yousefi, Sahar (author), Elmahdy, Mohamed S. (author), Lelieveldt, B.P.F. (author), Staring, M. (author)
In this paper we propose a supervised method to predict registration misalignment using convolutional neural networks (CNNs). This task is casted to a classification problem with multiple classes of misalignment: 'correct' 0-3 mm, 'poor' 3-6 mm and 'wrong' over 6 mm. Rather than a direct prediction, we propose a hierarchical approach, where...
journal article 2021
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Pezzotti, Nicola (author), Yousefi, Sahar (author), Elmahdy, Mohamed S. (author), van Gemert, Jeroen Hendrikus Fransiscus (author), Schuelke, Christophe (author), Doneva, Mariya (author), Nielsen, Tim (author), Lelieveldt, B.P.F. (author), Staring, M. (author)
Adaptive intelligence aims at empowering machine learning techniques with the additional use of domain knowledge. In this work, we present the application of adaptive intelligence to accelerate MR acquisition. Starting from undersampled k-space data, an iterative learning-based reconstruction scheme inspired by compressed sensing theory is...
journal article 2020
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Yousefi, Sahar (author), Manzuri Shalmani, M.T. (author), Lin, Jeremy (author), Staring, M. (author)
The problem of motion detection has received considerable attention due to the explosive growth of its applications in video analysis and surveillance systems. While the previous approaches can produce good results, the accurate detection of motion remains a challenging task due to the difficulties raised by illumination variations, occlusion...
journal article 2019
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Elmahdy, Mohamed S. (author), Jagt, Thyrza (author), Zinkstok, Roel Th. (author), Qiao, Yuchuan (author), Shahzad, Rahil (author), Sokooti, Hessam (author), Yousefi, Sahar (author), Incrocci, Luca (author), Marijnen, C.A.M. (author), Hoogeman, Mischa (author), Staring, M. (author)
Purpose: To develop and validate a robust and accurate registration pipeline for automatic contour propagation for online adaptive Intensity-Modulated Proton Therapy (IMPT) of prostate cancer using elastix software and deep learning. Methods: A three-dimensional (3D) Convolutional Neural Network was trained for automatic bladder segmentation...
journal article 2019
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Westerveld, W.J. (author), Pozo, J. (author), Leinders, S.M. (author), Yousefi, M. (author), Urbach, H.P. (author)
We investigate directional couplers in silicon-on-insulator photonic technology. We theoretically and experimentally demonstrate a large coupling-induced phase delay that occurs when nearly all light is coupled from one waveguide to the other, i.e., when the coupler operates as a cross-coupler. We show that even a tiny asymmetry in the two...
journal article 2013
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Westerveld, W.J. (author), Leinders, S.M. (author), Van Dongen, K.W.A. (author), Urbach, H.P. (author), Yousefi, M. (author)
Marcatili's famous approximate analytical description of light propagating through rectangular dielectric waveguides, published in 1969, gives accurate results for low-index-contrast waveguides. However, photonic integrated circuit technology has advanced to high-index-contrast (HIC) waveguides. In this paper, we improve Marcatili's model by...
journal article 2012
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Westerveld, W.J. (author), Pozo, J. (author), Harmsma, P.J. (author), Schmits, R. (author), Tabak, E. (author), Van den Dool, T.C. (author), Leinders, S.M. (author), Van Dongen, K.W.A. (author), Urbach, H.P. (author), Yousefi, M. (author)
Recently there has been growing interest in sensing by means of optical microring resonators in photonic integrated circuits that are fabricated in silicon-on-insulator (SOI) technology. Taillaert et al. [Proc. SPIE6619, 661914 (2007)PSISDG0277-786X10.1117/12.738412] proposed the use of a silicon-waveguide-based ring resonator as a strain gauge....
journal article 2012
document
Westerveld, W.J. (author), Urbach, H.P. (author), Yousefi, M. (author)
We present an accurate and fast 3D simulation scheme for out-of-plane grating couplers, based on two dimensional rigorous (finite difference time domain) grating simulations, the effective index method (EIM), and the Rayleigh-Sommerfeld diffraction formula. In comparison with full 3D FDTD simulations, the rms difference in electric field is...
journal article 2011
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