Engineering, Turkey
Engineering, Turkey

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Zeng Y.,Nanyang Technological University | Yetis C.M.,Nanyang Technological University | Yetis C.M.,Mevlana University | Gunawan E.,Nanyang Technological University | And 2 more authors.
IEEE Transactions on Signal Processing | Year: 2013

This paper studies the achievable rates of Gaussian interference channels with additive white Gaussian noise (AWGN), when improper or circularly asymmetric complex Gaussian signaling is applied. For the Gaussian multiple-input multiple-output interference channel (MIMO-IC) with the interference treated as Gaussian noise, we show that the user's achievable rate can be expressed as a summation of the rate achievable by the conventional proper or circularly symmetric complex Gaussian signaling in terms of the users' transmit covariance matrices, and an additional term, which is a function of both the users' transmit covariance and pseudo-covariance matrices. The additional degrees of freedom in the pseudo-covariance matrix, which is conventionally set to be zero for the case of proper Gaussian signaling, provide an opportunity to further improve the achievable rates of Gaussian MIMO-ICs by employing improper Gaussian signaling. To this end, this paper proposes widely linear precoding, which efficiently maps proper information-bearing signals to improper transmitted signals at each transmitter for any given pair of transmit covariance and pseudo-covariance matrices. In particular, for the case of two-user Gaussian single-input single-output interference channel (SISO-IC), we propose a joint covariance and pseudo-covariance optimization algorithm with improper Gaussian signaling to achieve the Pareto-optimal rates. By utilizing the separable structure of the achievable rate expression, an alternative algorithm with separate covariance and pseudo-covariance optimization is also proposed, which guarantees the rate improvement over conventional proper Gaussian signaling. © 1991-2012 IEEE.

Ali A.O.D.,University of Texas at Dallas | Yetis C.M.,Mevlana University | Torlak M.,University of Texas at Dallas
2016 IEEE International Conference on Communications, ICC 2016 | Year: 2016

In this paper, a multi-user uplink channel with correlated Rayleigh fading coefficients is considered. Optimal data packet length is derived for throughput maximization of the system with stop and wait automatic repeat request (SW-ARQ). For the throughput formulation of the SW-ARQ system, the packet error rate (PER) is analytically derived using a two-state Markov chain modelling of the signal-to-interference ratio (SIR) of the time-varying channel. For the PER formulation, second-order channel statistics including average level crossing rate (LCR) and average outage duration (AOD) are derived. Numerical results indicate the accuracy of the obtained theoretical results. The effect of increasing the number of interferers on the throughput is investigated w.r.t given SIR threshold. © 2016 IEEE.

Ali A.O.D.,University of Texas at Dallas | Yetis C.M.,Mevlana University | Torlak M.,University of Texas at Dallas
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC | Year: 2015

In this paper, distributed antenna selection algorithms are proposed to improve uncoded bit-error-rate (BER) in multIPle-input multIPle-output (MIMO) interference channels. The well known distributed power control algorithm by Yates in 1995 is used in all proposed schemes together with distributed antenna search algorithms, explicitly distributed exhaustive search, relaxed exhaustive search, and cross-entropy optimization techniques. While maximization of minimum signal-to-interference plus noise ratio (SINR) is the antenna selection metric, power minimization subject to SINR constraint is the power control problem used in the proposed schemes. It is shown that the proposed algorithms improve the BER of the system with acceptable sum-rate and fairness achieved in the system. Prioritization of streams can improve the BER of the system such as by assigning higher priorities to more important streams. Although for simplicity, equal stream priority, i.e., fairness among streams, is considered in this work, the proposed schemes can be extended to prioritization scenarios. © 2014 IEEE.

Yetis C.M.,Mevlana University | Zeng Y.,Nanyang Technological University | Anand K.,Nanyang Technological University | Guan Y.L.,Nanyang Technological University | Gunawan E.,Nanyang Technological University
IEEE Symposium on Wireless Technology and Applications, ISWTA | Year: 2013

Signal-to-interference plus noise ratio (SINR) and rate fairness in a system are substantial quality-of-service (QoS) metrics. The acclaimed SINR maximization (max-SINR) algorithm does not achieve fairness between user's streams, i.e., sub-stream fairness is not achieved. To this end, we propose a distributed power control algorithm to render sub-stream fairness in the system. Sub-stream fairness is a less restrictive design metric than stream fairness (i.e., fairness between all streams) thus sum-rate degradation is milder. Algorithmic parameters can significantly differentiate the results of numerical algorithms. A complete picture for comparison of algorithms can only be depicted by varying these parameters. For example, a predetermined iteration number or a negligible increment in the sum-rate can be the stopping criterion of an algorithm. While the distributed interference alignment (DIA) can reasonably achieve sub-stream fairness for the later, the imbalance between sub-streams increases as the preset iteration number decreases. Thus comparison of max-SINR and DIA with a low preset iteration number can only depict a part of the picture. We analyze such important parameters and their effects on SINR and rate metrics to exhibit numerical correctness in executing the benchmarks. Finally, we propose group filtering schemes that jointly design the streams of a user in contrast to max-SINR scheme that designs each stream of a user separately. © 2013 IEEE.

Altun H.,Mevlana University | Sinekli R.,Nigde University | Tekbas U.,Nigde University | Karakaya F.,Nigde University | Peker M.,Nigde University
INISTA 2011 - 2011 International Symposium on INnovations in Intelligent SysTems and Applications | Year: 2011

Color detection is generally a primary stage in most of the image processing application, if the application is based on the color information, such as road sign detection, face detection, skin color detection, object detection and object tracking etc. As the performance of subsequent modules in an image processing application is adversely affected by the previous modules, the accuracy of color detection with a high performance inevitably becomes crucial in some applications. This paper introduces a method for an efficient color detection in RGB space using an ensemble of experts in hierarchical structure. In this structure, a set of experts is assigned to evaluate R, G, B components of a pixel and then constructs a degree of membership to the set of predefined class of colors for the given pixel. Then a master neural network constructs its final decision based on the membership probabilities provided by the set of experts. Qualitative and quantitative evaluations of the results show that the proposed hierarchical structure of neural networks is superior over the conventional neural network classifier in color detection. © 2011 IEEE.

Ozkurt C.,Antalya International University | Camci F.,Antalya International University | Atamuradov V.,Mevlana University | Odorry C.,Antalya International University
Applied Energy | Year: 2016

Battery cost is one of the crucial parameters affecting high deployment of Electric Vehicles (EVs) negatively. Accurate State of Health (SoH) estimation plays an important role in reducing the total ownership cost, availability, and safety of the battery avoiding early disposal of the batteries and decreasing unexpected failures. A circuit design for SoH estimation in a battery system that bases on selected battery cells and its integration to EVs are presented in this paper. A prototype microcontroller has been developed and used for accelerated aging tests for a battery system. The data collected in the lab tests have been utilized to simulate a real EV battery system. Results of accelerated aging tests and simulation have been presented in the paper. The paper also discusses identification of the best number of battery cells to be selected for SoH estimation test. In addition, different application options of the presented approach for EV batteries have been discussed in the paper. © 2016 Elsevier Ltd.

Kaynar M.,Konya Education and Research Hospital | Sumer A.,Konya Education and Research Hospital | Salvarci A.,Mevlana University | Tekinarslan E.,Konya Education and Research Hospital | And 2 more authors.
Urologia Internationalis | Year: 2013

This paper presents the use of the single-step micropercutaneous nephrolithotomy (microperc) procedure for the treatment of a 13-mm renal stone using a 4.85-Fr 'all-seeing needle' in a 2-year-old toddler. In the current literature to date, this is the youngest case. Moreover, the advantages and reliability of this technique in toddler renal stone treatment are also evaluated. © 2013 S. Karger AG, Basel.

Isik E.,Mevlana University | Bulduk S.,Mevlana University
Journal of Marital and Family Therapy | Year: 2015

The purpose of the current study was to examine the validity and reliability of (Journal of Marital and Family Therapy 2003, 29, 209) Differentiation of Self Inventory-Revised (DSI-R; Skowron & Schmit, 2003) in Turkish adults. The DSI-R was translated, independently back-translated, and revised. Two independent samples of adults over the age of 25 were used. The original 46-item DSI-R was not supported by the data derived from Sample 1 (n = 221). However, a revised 20-item, four-factor model fit the data well. This 20-item model was subsequently cross-validated with a second sample of Turkish adults (n = 187). Scale scores showed adequate internal consistency, 5-week test-retest reliability, and satisfactory convergent and criterion-related validity. It was concluded that Turkish DSI-R (DSI-T) is a valid and reliable measure to assess an individual's differentiation level. In light of the findings, implications for the use of the DSI-T and ideas for future research are discussed. © 2015 American Association for Marriage and Family.

Abdulrahman M.,Mevlana University | Gwadabe T.R.,Mevlana University | Abdu F.J.,Mevlana University | Eleyan A.,Mevlana University
2014 22nd Signal Processing and Communications Applications Conference, SIU 2014 - Proceedings | Year: 2014

This paper proposed a facial expression recognition approach based on Gabor wavelet transform. Gabor wavelet filter is first used as pre-processing stage for extraction of the feature vector representation. Dimensionality of the feature vector is reduced using Principal Component Analysis (PCA) and Local binary pattern (LBP) algorithms. Experiments were carried out of using Japanese female facial expression (JAFFE) database. In all experiments conducted using JAFFE database, results obtained reveal that GW+LBP has outperformed other approaches in this paper with an average recognition rate of 90% under the same experimental setting. © 2014 IEEE.

A sound content analysis is proposed to detect incident at intersections, which is suitable to implement on hardware such as FPGA. Due to confusion between the sound classes, an hierarchical classifier architecture is proposed to improve the classification performance. The proposed architecture and the feature extraction algorithm are suitable for parallel implementation. © 2012 IEEE.

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