7,628 research outputs found
Steve Freear Passes the Torch as the Editor-in-Chief of IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
No full textAs the New Year starts and after 6 years of serving as the Editor-in-Chief of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (UFFC), Steven Freear passes the torch to Peter A. Lewin
Compressive Sensing for Damage Detection in Composite Aircraft Wings
No full textThis work deals with an ultrasonic guided wave structural health monitoring (SHM) system for composite aircraft wing damage inspection. The main idea is to use piezoelectric discs bonded to various parts of the aircraft wing, in a form of relatively sparse arrays, to generate and receive ultrasonic guided waves aimed at detecting defects. The development of a structural monitoring system able to inspect large composite structures and to communicate remotely to the central unit is challenging due to both the huge number of piezoelectric sensors needed and the high sampling frequency of the recorded signals. To address this problem, here a low rate sampling system has been developed by using a modified version of Compressive Sensing (CS) technique that exploits the sparse representation of dispersive and anisotropic ultrasonic guided waves in the frequency warped basis. The CS framework is applied to lower the sampling frequency and to enhance defect localization performances in composite material through the analysis of anisotropic guided waves propagation. The approach is based on the inverse Warped Frequency Transform (WFT) as the sparsifying basis for the CS acquisition and to compensate the dispersive behavior of guided waves for several different directions of propagation. As a result, an automatic detection procedure to locate defect-induced reflections has been successfully tested on Comsol software simulated guided waves propagating in an composite wing specimen
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Compressive sensing with frequency warped compensation for damage detection in composite plate
No full textThis work focuses on an ultrasonic guided wave structural health monitoring (SHM) system development for composite plate inspection. The development of an in situ health monitoring system that can inspect large areas and communicate remotely to the inspector is highly computational demanding due to both the huge number of piezoelectric sensors needed and the high sampling frequency. To address this problem, a general approach for low rate sampling is developed. Compressive Sensing (CS) has emerged as a potentially viable technique for the efficient acquisition that exploits the sparse representation of dispersive ultrasonic guided waves in the frequency warped basis. The framework is applied to lower the sampling frequency and to enhance defect localization performances of Lamb wave inspection systems. As a result, an automatic detection procedure to locate defect-induced reflections was demonstrated and successfully tested on simulated Lamb waves propagating in a carbon fiber plate using PZFlex software. The proposed method is suitable for defect detection and can be easily implemented for real application to structural health monitoring
Frequency warping compressive sensing for structural monitoring of aircraft wing
No full textThis work focuses on an ultrasonic guided wave structural health monitoring (SHM) system development for aircraft wing inspection. The performed work simulate small, low-cost and light-weight piezoelectric discs bonded to various parts of the aircraft wing, in a form of relatively sparse arrays, for cracks and corrosion monitoring. The piezoelectric discs take turns generating and receiving ultrasonic guided waves. The development of an in situ health monitoring system that can inspect large areas and communicate remotely to the inspector is highly computational demanding due to both the huge number of Piezoelectric sensors needed and the high sampling frequency. To address this problem, a general approach for low rate sampling is developed. Compressive Sensing (CS) has emerged as a potentially viable technique for the efficient acquisition that exploits the sparse representation of dispersive ultrasonic guided waves in the frequency warped basis. The framework is applied to lower the sampling frequency and to enhance defect localization performances of Lamb wave inspection systems. The approach is based on the inverse Warped Frequency Transform (WFT) as the sparsifying basis for the Compressive Sensing acquisition and to compensate the dispersive behaviour of Lamb waves. As a result, an automatic detection procedure to locate defect-induced reflections was demonstrated and successfully tested on simulated Lamb waves propagating in an aluminum wing specimen using PZFlex software. The proposed method is suitable for defect detection and can be easily implemented for real application to structural health monitoring
Steven Bialer and Patti Smith, July 1978
No full textMusician, poet, and author Patti Smith sits on a bed in a hotel room in July 1978. The photograph was taken by Don Hamerman as part of a session for "Unicorn Times," an alternative performing arts periodical in Washington, D.C. Steven Bialer, the Design Director for "Unicorn Times," is seated on the bed next to Smith
Steven Garber
No full textSteven Garber speaks on the importance and value of truth.
Steven Garber is the principal of The Washington Institute for Faith, Vocation & Culture, which is focused on reframing the way people understand life, especially the meaning of vocation and the common good. A consultant to foundations, corporations and educational institutions, he is a teacher of many people in many places. The author of The Fabric of Faithfulness: Weaving Together Belief and Behavior, and Visions of Vocation: Common Grace for the Common Good, he is also a contributor to the books, Faith Goes to Work: Reflections from the Marketplace, and Get Up Off Your Knees: Preaching the U2 Catalogue. He lives with his wife Meg in Virginia
Steven Yedinak Interview
No full textLTC (RET) Steven M. Yedinak commissioned in the U. S. Army Infantry in 1963 and subsequently spent 26 years in Special Forces and Airborne Infantry. He served two combat tours in Vietnam (1966-67 & 1971-1972), and started the Mobile Guerrilla Force. He is the author of Hard to Forget: An American with the Mobile Guerrilla Force in Vietnam (Random House, 1998). He retired from the Army in 1989
Gamification is broken. An interview with Steven Poole
No full textSteven Poole is the author of Trigger Happy (2000. New York, NY: Arcade Publish), Unspeak (2006. New York, NY: Grove Press), and You Aren’t What You Eat (2012. In press). He has written extensively on books, culture, and videogames for The Guardian and other publications
Steven Pinker on language and thought
No full textEducação Superior::Linguística, Letras e Artes::LinguísticaThis video presents an exclusive preview of Steven Pinker's book: the stuff of thought. The author looks at language and how it expresses what goes on in our minds and how the words we choose communicate much more than we realize. For Steven Pinker, the brilliance of the mind lies in the way it uses just two processes to turn the finite building blocks of our language into infinite meanings. The first is metaphor: we take a concrete idea and use it as a stand-in for abstract thoughts. The second is combination: we combine ideas according to rules, like the syntactic rules of language, to create new thoughts out of old one
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