Consistency and population monotonicity in social and economic networks

Ankara : The Department of Economics and the Institute of Economics and Social Sciences of Bilkent University, 1999.Thesis (Master's) -- Bilkent University, 1999.Includes bibliographical references leaves 19.In this study, we analyze consistency and population monotonicity principles focusing on the pairwise stability solution in social and economic networks. First, it is examined which allocation rules and value functions lead to the consistent pairwise stable graphs. Second, population monotonic allocation rules with respect to the pairwise stability solution are analyzed.Yılmaz, ÖzgürM.S

Quasi-Newton FDE in One-Bit Pseudo-Randomly Quantized Massive MIMO-OFDM Systems

This letter offers a new frequency domain equalization (FDE) scheme that can work with a pseudo-random quantization (PRQ) scheme utilizing non-zero threshold quantization in one-bit uplink multi-user massive multiple-input multiple-output (MIMO) systems to mitigate quantization distortion and support high-order modulation schemes. The equalizer is based on Newton's method (NM) and applicable for orthogonal frequency division multiplexing (OFDM) transmission under frequency-selective fading by exploiting the properties of massive MIMO. We develop a low-complexity FDE scheme to obtain a quasi-Newton method. The proposed detector outperforms the benchmark detector with comparable complexity

Error Rate Analysis of GF(q) Network Coded Detect-and-Forward Wireless Relay Networks Using Equivalent Relay Channel Models

This paper investigates simple means of analyzing the error rate performance of a general q-ary Galois Field network coded detect-and-forward cooperative relay network with known relay error statistics at the destination. Equivalent relay channels are used in obtaining an approximate error rate of the relay network, from which the diversity order is found. Error rate analyses using equivalent relay channel models are shown to be closely matched with simulation results. Using the equivalent relay channels, low complexity receivers are developed whose performances are close to that of the optimal maximum likelihood receiver.Comment: 28 pages, 10 figures. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Embracing Off-the-Grid Samples

Many empirical studies suggest that samples of continuous-time signals taken at locations randomly deviated from an equispaced grid (i.e., off-the-grid) can benefit signal acquisition, e.g., undersampling and anti-aliasing. However, explicit statements of such advantages and their respective conditions are scarce in the literature. This paper provides some insight on this topic when the sampling positions are known, with grid deviations generated i.i.d. from a variety of distributions. By solving the basis pursuit problem with an interpolation kernel we demonstrate the capabilities of nonuniform samples for compressive sampling, an effective paradigm for undersampling and anti-aliasing. For functions in the Wiener algebra that admit a discrete $s$-sparse representation in some transform domain, we show that $\mathcal{O}(s\log N)$ random off-the-grid samples are sufficient to recover an accurate $\frac{N}{2}$-bandlimited approximation of the signal. For sparse signals (i.e., $s \ll N$), this sampling complexity is a great reduction in comparison to equispaced sampling where $\mathcal{O}(N)$ measurements are needed for the same quality of reconstruction (Nyquist-Shannon sampling theorem). We further consider noise attenuation via oversampling (relative to a desired bandwidth), a standard technique with limited theoretical understanding when the sampling positions are non-equispaced. By solving a least squares problem, we show that $\mathcal{O}(N\log N)$ i.i.d. randomly deviated samples provide an accurate $\frac{N}{2}$-bandlimited approximation of the signal with suppression of the noise energy by a factor $\sim\frac{1}{\sqrt{\log N}}$

Stoma Prolapse

The incidence of prolapse which is a late complication of stoma ranges between 0–25%. In this study the records of the patients who had been treated and followed up with the diagnosis of stoma prolapse between 1995 -2005 in the General Surgery Department of Dicle University Hospital were examined, retrospectively. There were 12 patients (5 men, 7 women) with a mean age of 51,6±15.01 years. The causes of stoma construction were malign diseases in 9 patients and benign diseases in 3 of them. The average time between construction of stoma and formation of prolapse was 10,9±6.84 month. The type of stoma was loop in 7 patient, end stoma in 4 patient and double bowel enterostomy in 1 patient. Of nine patients with stoma prolapse had been subjected chemotherapy. The overall rate of stomal prolapsus was 3,1% in this series. It was 10,8% in patients who had received chemoradiotherapy. Since stomal prolasus is a serious complication and its reconstruction needs general anesthesia great care should be shown when creatig a stoma