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Electrical and Computer Engineering

TÜBİTAK

Journal

Reconstruction

Publication Year

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Iterative Sensitivity Matrix-Based Magnetic Resonance Conductivity Tensor Imaging, Evren Deği̇rmenci̇ Jan 2019

Iterative Sensitivity Matrix-Based Magnetic Resonance Conductivity Tensor Imaging, Evren Deği̇rmenci̇

Turkish Journal of Electrical Engineering and Computer Sciences

Magnetic resonance conductivity tensor imaging (MRCTI) reconstructs high-resolution anisotropic conductivity images, which are proved to have critical importance in radio-oncological imaging as well as source localization fields. In the MRCTI technique, linearly independent current injections are applied to the region to be imaged and resulting magnetic flux densities are measured using magnetic resonance imaging techniques. In this study, a novel iterative reconstruction algorithm based on a sensitivity matrix approach is proposed and tested using both simulated and experimental measurements. Obtained results show that the proposed technique can reconstruct anisotropic conductivity images with high and position-independent spatial resolution in addition to …


Statistical Features-Based Comparison Of Analysis And Synthesis Of Normal And Epileptic Electroencephalograms For Various Wavelets, Revati Shriram, Mahalingam Sundhararajan, Supriya Shete, Nivedita Daimiwal Jan 2017

Statistical Features-Based Comparison Of Analysis And Synthesis Of Normal And Epileptic Electroencephalograms For Various Wavelets, Revati Shriram, Mahalingam Sundhararajan, Supriya Shete, Nivedita Daimiwal

Turkish Journal of Electrical Engineering and Computer Sciences

An electroencephalogram (EEG) is an electrical signal in microvolts captured noninvasively from the brain, which provides important and unique information about the brain. The frequency of an EEG signal lies between 0 and 100 Hz. Decomposition of an EEG signal into various bands such as alpha, beta, delta, theta, and gamma is essential in seizure-related studies. EEGs play a key role in the diagnosis of epileptic seizures and neurological disorders. In this paper, multiple wavelet families for decomposition and reconstruction are explored and are compared based on risk functions and reconstruction measures. While dealing with the wavelets it is a …


Analysis Of Reconstruction Performance Of Magnetic Resonance Conductivity Tensor Imaging (Mrcti) Using Simulated Measurements, Evren Deği̇rmenci̇, Behçet Murat Eyüboğlu Jan 2017

Analysis Of Reconstruction Performance Of Magnetic Resonance Conductivity Tensor Imaging (Mrcti) Using Simulated Measurements, Evren Deği̇rmenci̇, Behçet Murat Eyüboğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Magnetic resonance conductivity tensor imaging (MRCTI) was proposed recently to produce electrical conductivity images of anisotropic tissues. Similar to magnetic resonance electrical impedance tomography (MREIT), MRCTI uses magnetic field and boundary potential measurements obtained utilizing magnetic resonance imaging techniques. MRCTI reconstructs tensor images of anisotropic conductivity whereas MREIT reconstructs isotropic conductivity images. In this study, spatial resolution and linearity of five recently proposed MRCTI algorithms are evaluated using simulated measurements gathered from three different computer models. The results show that all five algorithms have quite similar reconstruction performances. Since the AB$_{z}$S algorithm is easier to apply compared to the other …


Reconstruction Of A Single Square Pulse Originally Having 40 Ps Width Coming From A Lossy And Noisy Channel In A Point To Point Interconnect, Alak Majumder, Bidyut Bhattacharyya Jan 2017

Reconstruction Of A Single Square Pulse Originally Having 40 Ps Width Coming From A Lossy And Noisy Channel In A Point To Point Interconnect, Alak Majumder, Bidyut Bhattacharyya

Turkish Journal of Electrical Engineering and Computer Sciences

The fundamental problem in high speed communication is that it suffers a lot of signal integrity issues due to dispersion (caused by dielectric variation with angular frequency), reflection (S$_{11})$, and insertion losses (S$_{12})$ of the channel made of copper. When a pulse width $\tau $ with magnitude V$_{0}$ is driven through a lossy channel, we observe a reduction in magnitude (due to S$_{12}$ and S$_{11})$ and an increase in pulse width (due to dispersion). It causes different values of skin effect and dielectric loss leading to different effective resistance at each segment as the pulse moves through the channel. This …