The Experts below are selected from a list of 378591 Experts worldwide ranked by ideXlab platform
Fu-kuo Chang - One of the best experts on this subject based on the ideXlab platform.
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A synthetic time-reversal Imaging Method for structural health monitoring
Smart Materials and Structures, 2004Co-Authors: Chun H. Wang, James T Rose, Fu-kuo ChangAbstract:This paper presents an experimental and theoretical investigation of the applicability of the time-reversal concept to guided waves in plate-like structures, where the stress waves are dispersive and of multi-modes. It is shownthat temporal and spatial focusing can be achieved through time reversal,although the dispersive behaviour of the flexural waves renders it impossible to exactly reconstruct the waveform of the original excitation. Based on the principle of the time-reversal concept, a digital Imaging Method suitable for distributed sensor/actuator networks has been developed. This new Method, which overcomes the limitation of the conventional phased array Method that operates under pulse-echo mode, provides an efficient Imaging Method for locating and approximate sizing of structural damages. In addition, it has been shown that signal strengths can be considerably enhanced by applying the present synthetic time-reversal Method, thus reducing the number of sensors and actuators required to achieve a given signal-to-noise ratio.
Chun H. Wang - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Laminar Damage in an Aluminium Panel by Diffraction Tomography Based Imaging Method Using Lamb Waves
2014Co-Authors: Eugene Chan, Chun H. Wang, Francis L.r. RoseAbstract:Most of the research on Structural Health Monitoring employs guided waves only to detect and locate damage in a plate-like structure. The purpose of this paper is to present a Diffraction Tomography based Imaging Method, using experimentally-determined scattered fields (Lamb wave signals) and numerically computed GreenÕs function, to characterise laminar damage in an aluminium panel. The approach is based on a recently derived extension of Diffraction Tomography which utilises the multi-static scattering matrix constructed from the measurements of the scattered field for every source and receiver pair, as well as the GreenÕs function of the structure which is its response to a point source. The Imaging results have provided for the first time an accurate characterisation of damage geometry and size derived from experimental data. These results are shown to compare favourably with those obtained from computational data, and they are significantly more accurate than previously reported results.
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A synthetic time-reversal Imaging Method for structural health monitoring
Smart Materials and Structures, 2004Co-Authors: Chun H. Wang, James T Rose, Fu-kuo ChangAbstract:This paper presents an experimental and theoretical investigation of the applicability of the time-reversal concept to guided waves in plate-like structures, where the stress waves are dispersive and of multi-modes. It is shownthat temporal and spatial focusing can be achieved through time reversal,although the dispersive behaviour of the flexural waves renders it impossible to exactly reconstruct the waveform of the original excitation. Based on the principle of the time-reversal concept, a digital Imaging Method suitable for distributed sensor/actuator networks has been developed. This new Method, which overcomes the limitation of the conventional phased array Method that operates under pulse-echo mode, provides an efficient Imaging Method for locating and approximate sizing of structural damages. In addition, it has been shown that signal strengths can be considerably enhanced by applying the present synthetic time-reversal Method, thus reducing the number of sensors and actuators required to achieve a given signal-to-noise ratio.
James T Rose - One of the best experts on this subject based on the ideXlab platform.
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A synthetic time-reversal Imaging Method for structural health monitoring
Smart Materials and Structures, 2004Co-Authors: Chun H. Wang, James T Rose, Fu-kuo ChangAbstract:This paper presents an experimental and theoretical investigation of the applicability of the time-reversal concept to guided waves in plate-like structures, where the stress waves are dispersive and of multi-modes. It is shownthat temporal and spatial focusing can be achieved through time reversal,although the dispersive behaviour of the flexural waves renders it impossible to exactly reconstruct the waveform of the original excitation. Based on the principle of the time-reversal concept, a digital Imaging Method suitable for distributed sensor/actuator networks has been developed. This new Method, which overcomes the limitation of the conventional phased array Method that operates under pulse-echo mode, provides an efficient Imaging Method for locating and approximate sizing of structural damages. In addition, it has been shown that signal strengths can be considerably enhanced by applying the present synthetic time-reversal Method, thus reducing the number of sensors and actuators required to achieve a given signal-to-noise ratio.
Helmut Ermert - One of the best experts on this subject based on the ideXlab platform.
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A synthetic aperture ultrasonic Imaging Method: Simulation
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1992Co-Authors: J. Ylitalo, Helmut ErmertAbstract:The synthetic aperture Imaging Method under study uses holographic approach to produce a two-dimensional image comparable to a B-scan. Instead of focused ultrasound a relatively wide beam with sector shaped beamprofile is applied in object insonification. Image is focused numerically in a microcomputer. Since reconstruction is performed in the spatial frequency domain the FFT-algorithms can be employed efficiently both in the wavefront backpropagation and in the near-field curvature compensation. Therefore the proposed Method is fast enough to be applied in a real-time Imaging system. In simulation a well-known tissue model with a continuous distribution of point scatterers combined with a simulated phantom is used in order to study the dynamical range and resolution of the Imaging Method. In medical diagnosis the poor dynamical range and resolution have been a serious limitation of the synthetic aperture Imaging Methods resulting, for example, in poor detection of cysts. This study indicates that with the present Imaging system good spatial and contrast resolution can be achieved througout the image. The errors in phase angle detection, however, have a strong effect on the image quality. Therefore, a compromise has to be made between the spatial resolution (beam width) and the sensitivity to phase angle errors.
Peter K Sorger - One of the best experts on this subject based on the ideXlab platform.
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abstract b21 probing tumor heterogeneity and immune infiltration with cyclic immunofluorescence cycif a robust multiplexed Imaging Method
Cancer immunology research, 2017Co-Authors: Benjamin Izar, Sabrina Hawthorne, Josh Nordberg, Eric Kaldjian, Peter K SorgerAbstract:Tumor microenvironment, defined by surrounding stromal/immune cells as well as blood vessels, plays an important role in disease progression and therapy resistance. Increasing understanding of the heterogeneity in both tumor and its microenvironment will be crucial to development more effective therapies. Recently, several studies employing state-of-the-art single-cell sequencing Methods reveal enormous complexity in tumor microenvironment. However, the spatial information and cell-to-cell interaction could not be preserved in these dissociated cells. Immunofluorescence has been widely used in different fields of biological and medical research for decades. The ability to obtain in situ and single-cell information makes this technique particularly important in tumor biology. However, biochemical and optical constraints limit the number of signals that could be captured simultaneously within the same sample. We have developed the CycIF (Cyclic Immunofluorescence), an easy and low-cost Method to increase the multiplexity of conventional immunofluorescence. The CycIF Method has been first applied in pre-clinical drug discovery, cancer and stem cell biology with adherent cell cultures. In here, we modified the original CycIF Method for IHC/IF on FFPE samples, and used that to probe tumor heterogeneity, microenvironment and immune infiltration in various types of tumors. Up to 30 different antigens/markers could be simultaneously detected in different tumor samples, and these makers represent a wide range of biological processes, including the key molecules for lymphocyte surface makers (CD45, CD4, CD8, CD20, CD11c), immune checkpoints (PD-1, PD-L1), stromal/EMT proteins (E-Cadherin, Vimentin), cell cycle regulators (CycD1, PCNA, Ki67, pRB, p21/CIP), signaling proteins (EGFR, pERK, pS6) and apoptosis mediators (p53, Bax, Bcl-2, Survivin). Our study not only provides the first detailed map of tumor and its immune microenvironment, but also illustrates a robust multiplexed Imaging platform for probing tumor heterogeneity. Citation Format: Jia-Ren Lin, Benjamin Izar, Sabrina Hawthorne, Josh Nordberg, Eric Kaldjian, Peter Sorger. Probing tumor heterogeneity and immune infiltration with Cyclic Immunofluorescence (CycIF), a robust, multiplexed Imaging Method. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B21.
