12350

11310

كارشناسي ارشد

مخابرات سيستم

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1395

ده، 83ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

رسول اميرفتاحي

محمد مهدي نقش

محمدرضا احمدزاده، بهزاد نظري

1396/01/23

كتابنامه

برق و كامپيوتر

مهندسي برق و كامپيوتر

ID11310

Improvement and Development of Single Trial ERP Extraction Methods for Analysis of Time Perception Mechanism in Kids Sepehr Mortaheb s mortaheb@ec iut ac ir Date of Submission 2017 03 08 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Dr Rasoul Amirfattahi Advisor Dr Mohammad Mahdi NaghshAbstractTime perception is an intrinsic ability of human beings and animals which is used to percept andestimate time duration between events How time perception system functions and its characteris tics in human beings of different ages and sexes are still among biggest mysteries of neuroscience In order to analyze this mechanism various imaging and brain signal recording techniques such asfMRI PET and EEG have been utilized so far One of the inexpensive and easy methods with ahigh temporal resolution is to use Event Related Potentials ERP These signals are generated dur ing EEG recording when subjects are stimulated with visual auditory or somatosensory stimuli The main drawback of utilizing these signals is their very low signal to noise ratio SNR whichmakes difficult their observation and extraction from ongoing brain activity signals The most con ventional method to extract these signals is synchronized averaging In this method the subjectis stimulated with frequent stimuli and their responses are recorded Recorded signals are alignedaccording to the stimulus time and their average is calculated to remove random noise and extractERPs The high number of trials required to reach desired SNR nonstationarity of ERPs in consec utive trials and loss of useful physiologic information exist in variability of ERPs in various trialsare the most important disadvantages of this method As a result various algorithms are proposed toextract ERPs in a single trial manner In this thesis different single trial ERP extraction methods arestudied and their advantages and disadvantages are examined To improve the efficiency of thesealgorithms in very low SNR conditions a two stage algorithm is proposed At the first stage aver age of some trials are calculated and wavelet coefficients related to the averaged ERP are extractedusing a new approach in wavelet transform and extended taut string algorithm These coefficientsare utilized as priori information in second stage to extract single trial ERPs by means of adaptivenoise cancelers and wavelet reconstruction Simulation results with additive white Gaussian noiseand real EEG noise show the superiority of proposed algorithm over conventional and recently pro posed algorithms for single trial ERP extraction and trial to trial amplitude variability tracking Inaddition single trial analysis of time perception signals shows that CNV component of trials in

رسول اميرفتاحي

محمد مهدي نقش

محمدرضا احمدزاده، بهزاد نظري