In this paper, echo cancellation is done using genetic algorithm (GA). The genetic algorithm is implemented by two kinds of crossovers; heuristic and microbial. A new procedure is proposed to estimate the coefficients of adaptive filters used in echo cancellation with combination of the GA with Least-Mean-Square (LMS) method. The results are compared for various values of LMS step size and diff...

hepatomegaly, decrease in the liver paranchymal echo and increase in the gallbladder wall thickness has been shown in acute viral hepatitis. the present study was done to determine sonographic changes in acute viral hepatitis. we performed liver and bile ducts sonography and specific tests on 42 patients (mean age: 31.5 and 61% male) with acute viral hepatitis. gallbladder wall thickness was se...

background: evaluation of herbicide pollution in aquatic environments needs the great concern and the most important echo-pollutant effects of herbicides are related to their effects on non target aquatic organisms. native fish can serve as a proper bio-indicator for evaluation  of pollution on aquatic ecosystems. objectives: to find environmentally friendly herbicides, in this study the acute ...

introduction contrast-enhanced fluid-attenuated inversion recovery (flair) is one of the mri sequences that can be used for detection and evaluation of pathological changes in the brain. in this work, we have studied the effect of different echo times (te) on the maximum relationship between signal intensity and concentration of the contrast agent using the flair sequence. materials and methods...

introduction echo-planar imaging (epi) is a group of fast data acquisition methods commonly used in fmri studies. it acquires multiple image lines in k-space after a single excitation, which leads to a very short scan time. a well-known problem with epi is that it is more sensitive to distortions due to the used encoding scheme. source of distortion is inhomogeneity in the static b0 field that ...

in this paper a new method for nondestructive testing or nondestructive evaluation is proposed for glass-epoxy composite. for this purpose, impact-echo is used to evaluate the properties of composite materials, detecting internal defects and thickness measurement. in the impact-echo method a steel ball impacts on a composite plate and generates stress waves or p-waves which will be transferred ...

one of the most common signals used for achieving high range resolution in radar is stepped-frequency signals. when a target is stationary in these radars, dft (discrete fourier transform) based processing is used to attain high range resolution profile (hrrp). however, in the case of moving target, due to spreading of the echo signal spectrum, dft based processing is not optimal and decreases ...