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The severity of coronary artery diseases is assessed based on morphological and functional stenosis.The study Oil detection of coronary artery diseases based on morphological lesions has unveiled its short comings for evaluation of the seriousness of the disease.Therefore,many research groups diagnose the coronary artery diseases by functional stenosis.From functional aspect,studies of x-ray angiography algorithms for blood flow and velocity measurement are potentially clinically important and are an actively researched subject,which Can accurately diagnose the coronary diseases from functional stenosis aspect.Based on the angiographic images,the article describes formulation and characteristics of existing coronary blood flow and velocity techniques such as tracking and computational methods.Tracking methods can be divided into four classes:bolus transport time algorithms,continuous velocity determination from two-dimensional(time-distance)parametric images,contrast traversal distance algorithms,and droplet tracking algorithms.Computational methods can be divided into six classes:indicator-dilution or Stewart-Hamilton method,first-pass distribution analysis,inverted continuity equation algorithms,inverse mass transport problem approach,optical flow type algorithms,and the fluid continuity method.
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Alzheimer’s disease (AD), one of the most common causes of dementia in the elderly, is a progressive neurodegenerative disorder. Accurate diagnosis in the early stage of AD is crucial for its treatment. Several methods based on signal processing and image analysis are presented. In particular, neuron image processing which plays an important role in AD diagnosis and its pathological analysis is discussed in detail.
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Objective To further analyze the chaos characteristics of heart rate variability(HRV) signals.Methods Analyzed HRV was obtained from 40 healthy subjects(20 olds,20 youngs) by means of Cao algorithm;Stability criteria was proposed to determine minimum embedding dimension;Meanwhile,we advanced a new quantative analysis method of studying HRV deterministic component,and applied the method to the old and young groups.Results Each subject's HRV was composed of both stochastic and deterministic components;Stability criteria could solve the subjective problem when determine minimum embedding dimension by Cao algorithm;Deterministic component in healthy old subjects was higher than the young.Conclusion In this paper,we have proved that HRV is deterministice chaos;Stability criteria works well for determining minimum embedding dimension;HRV decreases as age increases.
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Objective To meet the demand of ECG signal processing in high sampling rate,a simple and narrowband power-line interference notch filter is designed.Methods Based on the band elimination filter which was combined with counteraction of zeros and poles and the interpolation theory,we designed a simple,integral coefficient filter with adjustable filter bandwidth.To eliminate the Gibbs phenomena,we adopted the average filter in linear segments which was designed by the former.Results With our designed filter,50 Hz power-line interference in high sampling rate was efficiently removed,and the filter coefficients were simple,integral,and convenient.Conclusion The new design can produce a narrowband notch filter in high sampling rate,remove the 50 Hz power-line interference effectively,and retain the significant signal as much as possible to meet the needs of ECG analysis.
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The paper introduced the structure of digital hearing aid in brief firstly, then analyzed and compared signal processing algorithms applied in digital hearing aid, serving respectively in multi-channel frequency compensation, noise reduction and acoustic feedback cancellation. Finally, several special signal processing techniques used in digital hearing aid were introduced.