Results 211 to 220 of about 21,797 (258)
Some of the next articles are maybe not open access.
Linear attenuation coefficients for compensator based imrt
Australasian Physics & Engineering Sciences in Medicine, 2007With rapid technological improvements in computer driven 3-D radiotherapy treatment planning systems (RTPS) the use of compensating filters for intensity modulated radiation therapy (IMRT) will dramatically increase the ease of treatment. The procedure for commissioning .decimal (Sanford, Florida) compensators involved the measurement of the effective ...
T, Bartrum +3 more
openaire +2 more sources
Equalization of Crackle Sounds to Compensate Thorax Attenuation
IEEE Transactions on Instrumentation and Measurement, 2014Lung sounds recorded on the chest are attenuated by the thorax and thorax-microphone interface. In order to recover waveforms similar to the ones generated within the lungs, this paper equalizes crackle sounds recorded on the chest. From an experiment in which eight subjects (seven men) took part, an estimation of the channel (thorax and thorax ...
Daniel Ferreira da Ponte +3 more
openaire +1 more source
Rational Gain Compensation for Attenuation in Cardiac Ultrasonography
Ultrasonic Imaging, 1983A new method of compensating for the attenuation of ultrasound by chest wall, myocardium and blood has been devised by using an optimum threshold to distinguish between blood and myocardium. This allows changing receiver gain at rates suitable for either blood or myocardium for each line-of-sight forming a real-time image.
H E, Melton, D J, Skorton
openaire +2 more sources
Journal of Nuclear Cardiology, 1996
Attenuation is believed to be one of the major causes of false-positive cardiac single-photon emission computed tomographic perfusion images. This article provides an introduction to the approaches used to correct for nonuniform attenuation once a patient-specific attenuation map is available.
M A, King +4 more
openaire +2 more sources
Attenuation is believed to be one of the major causes of false-positive cardiac single-photon emission computed tomographic perfusion images. This article provides an introduction to the approaches used to correct for nonuniform attenuation once a patient-specific attenuation map is available.
M A, King +4 more
openaire +2 more sources
IEEE Transactions on Image Processing, 2010
Ultrasound B-scan exhibits shadowing and enhancement artifacts due to acoustic wave propagation and spatially varying scatter attenuation across layers of tissues. These artifacts hide underlying echo signals that are truly clinically indicative of diseases.
Yongjian Yu, Jue Wang 0005
openaire +2 more sources
Ultrasound B-scan exhibits shadowing and enhancement artifacts due to acoustic wave propagation and spatially varying scatter attenuation across layers of tissues. These artifacts hide underlying echo signals that are truly clinically indicative of diseases.
Yongjian Yu, Jue Wang 0005
openaire +2 more sources
Attenuation compensation in distributed amplifier design
IEEE Transactions on Microwave Theory and Techniques, 1989A high-gain common-gate FET that presents at its drain a broadband impedance characterized by a (frequency-dependent) negative resistance and a capacitance is examined theoretically and experimentally. Loading the input and/or the output lines of a distributed amplifier with this circuit reduces the signal losses, leading to an increase in the allowed ...
S. Deibele, J.B. Beyer
openaire +1 more source
Wave Equation Migration with Attenuation Compensation
Proceedings, 2011We introduce a new viscoacoustic Wave Equation Migration (WEM) for media with attenuation. Our solution is based on a Fourier Finite-Difference (FFD) scheme for migration by wavefield continuation. Similarly to the acoustic solution, the viscoacoustic migration consists of three terms: a phase-shift extrapolation, a thin-lens correction, and a finite ...
A.A. Valenciano +3 more
openaire +1 more source
Sensitivity and attenuation compensated training of multilayered networks
Neural Parallel Sci. Comput., 1998Summary: Until recently, most studies of feedforward networks have focused on depth 2 networks (i.e., networks with one hidden layer only). Theoretical and empirical investigations of deep networks have been hindered by difficulties in mathematical analysis and practical training of these networks. In this paper, some of the reasons for this difficulty
T. Yin, Haroon A. Babri, Dinesh P. Mital
openaire +2 more sources
Phase compensated microstrip variable attenuator
APMC 2001. 2001 Asia-Pacific Microwave Conference (Cat. No.01TH8577), 2002This paper is devoted to an amplitude control device with compensated phase component based on the Q control of a microstrip resonator, so that the amplitude of S21 can be controlled without phase shifting at a certain frequency. The device consists of a PIN diode and two microstrip lines coupled by an aperture slot on a ground plane.
T. Fukusako, Y. Isoda, N. Mita
openaire +1 more source
Adaptive disturbance attenuation: Friction compensation
19981In this chapter we illustrate one further advantage of PBC: the possibility of attenuating the effect of bounded external disturbance via high-gain feedback. Roughly speaking, this feature stems from the fundamental property of infinite gain margin of passive maps, hence stability is preserved when placed in closed-loop with high-gain operators.
Romeo Ortega +3 more
openaire +1 more source