Özgür Yılmaz

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The second order Sigma-Delta (Σ∆) scheme with linear quantization rule is analyzed for quantizing finite unit-norm tight frame expansions for R d. Approximation error estimates are derived, and it is shown that for certain choices of frames the quantization error is of order 1/N 2 , where N is the frame size. However, in contrast to the setting of(More)
In this paper, we address the problem of under-determined Blind Source Separation (BSS) of anechoic speech mixtures. We propose a demixing algorithm that exploits the sparsity of certain time-frequency expansions of speech signals. Our algorithm merges q-basis-pursuit with ideas based on the degenerate unmixing estimation technique (DUET) [1]. There are two(More)
Degenerate Unmixing Estimation Technique (DUET) is a technique for blind source separation (BSS). Unlike the ICA based BSS techniques, DUET is a time-frequency scheme that relies on the so-called W-disjoint orthogonality (WDO) property of the source signals, which states that the windowed Fourier transforms of different source signals have statistically(More)
Missing-trace interpolation aims to reconstruct regularly sampled wavefields from periodically sampled data with gaps caused by physical constraints. While transform-domain sparsity promotion has proven to be an effective tool to solve this recovery problem, recent developments in randomized acquisition in marine, via randomized coil sampling or randomized(More)
In this paper, we address the problem of under-determined blind source separation (BSS), mainly for speech signals, in an anechoic environment. Our approach is based on exploiting the sparsity of Gabor expansions of speech signals. For parameter estimation, we adopt the clustering approach of DUET [19]. However, unlike in the case of DUET where only two(More)
We introduce a family of coarse quantization algorithms for heavily oversampled Gabor expansions of certain classes of functions in L 2 (R). These algorithms, which we call the TF quantization algorithms, are inspired by sigma–delta modulation, a widely implemented coarse quantization scheme for oversampled bandlimited functions. We show that the TF(More)
Deceased-donor and live-donor kidneys are the two sources for transplantation, and these sources are utilized via two different programs. One of these programs, a paired kidney donation (PKD), involves two donor-patient pairs, for each of whom transplantation from donor to intended recipient is not possible due to medical incompatibilities, but such that(More)
  • Özgür Yılmaz, Say A C Cem, H Levent Akın, Assist Prof Ali, Karatay, V Özet
  • 2005
ACKNOWLEDGEMENTS I wish to express my appreciation to my thesis supervisor, Prof. A. C. Cem Say for his enlightening and insightful advice throughout this thesis. The most important ideas of this work came out in the joyful brainstorming sessions we held together. I am indebted to all the teachers passed through my life, who have equipped me with all the(More)
This study evaluated the effect of retroperitoneal adipose tissue on testicular venous drainage and tested the nutcracker phenomenon by clinical and imaging findings. A total of 95 patients were included. The patients were evaluated with a detailed medical history and physical examination for varicocele. Their weight, height and waist circumference were(More)