5 sonuçlar
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Yayın Power control in the cognitive cooperative multiple access channel(IEEE, 2012) Kaya, Onur; İşleyen, MuratWe extend several encoding and decoding techniques from cooperative communications framework, to a cognitive radio system consisting of a primary user (PU) and a secondary user (SU), sending their messages to a common receiver. Assuming that the transmitters and the receiver have full channel state information (CSI) collected and distributed by the common receiver, and that the SU knows the PU's codebook, the cooperation is obtained by block Markov superposition coding, and backwards decoding, which yield a causal overlay scenario. We formulate two rate optimization problems with the aim of, (i) maximizing the sum rate of the system, and (ii) maximizing the rate of the secondary user. We obtain the optimal power allocations for both cases, and the resulting rate regions. The power controlled cooperation turns out to be especially useful when maximizing the sum rate of the system, as it gives the PU significant rate rewards for allowing the cognitive transmitter to access its resources.Yayın Efficient quality of multimedia experience using perceptual quality metrics(Springer-Verlag Berlin, 2016) Gaurav, Rahul; Ateş, Hasan FehmiAlthough there are very few metrics which correlate well with the Human Visual System (HVS), most of them do not. We extensively studied about the Video Quality Assessment (VQA) of 2D svideos for enhancing the Quality of Experience (QoE) using better Quality of Service (QoS). We propose a solution which helps us to find a high correlation between HVS and the objective metrics using Perceptual Quality Metrics (PQM). The motive behind this work is to introduce an objective metric that is adequate to predict the Mean Opinion Score (MOS) of distorted video sequences based on the Full Reference (FR) method.Yayın A novel noise robust and low bit rate speech coding algorithm(IEEE, 2009) Güz, Ümit; Gürkan, Hakan; Yarman, Bekir Sıddık BinboğaIn this work, a new noise robust and variable length frame based speech modeling method is introduced. This method consists of three major steps which includes noise removal algorithm, coding and encoding algorithms, respectively. Coding and encoding parts are developed based on SYMPES (SYsteMatic Procedure for Predefined Envelope and Signature sequence sets). These sets have been developed in two types which represent voiced and unvoiced parts of the speech signals separately in order to obtain more efficient coding strategy and higher compression ratio while preserving the perceptual quality of the speech signals. As an extension of our previous works our new framework is not only consider the coding of the clean speech signals but also noisy speech signals. The new noise robust module suppresses the noise and delivers the clean speech signal to the newly designed modeling part. The modeling part promises higher compression ratios by switching to the more appropriate type of predefined sets take into account the voiced and unvoiced frames.Yayın A novel image compression method based on classified energy and pattern blocks: initial results(Springer, 2010) Güz, Ümit; Gürkan, Hakan; Yarman, Bekir Sıddık BinboğaIn this work, a new method for the compression of the images based on the generation of the so called classified energy and pattern blocks is introduced and the initial results are presented. The initials results proved that the new method provides considerable image compression ratios and image quality even at low bit rates.Yayın A novel hybrid electrocardiogram signal compression algorithm with low bit-rate(Springer, 2010) Gürkan, Hakan; Güz, Ümit; Yarman, Bekir Sıddık BinboğaIn this paper, a novel hybrid Electrocardiogram (ECG) signal compression algorithm based on the generation process of the Variable-Length Classified Signature and Envelope Vector Sets (VL-CSEVS) is proposed. Assessment results reveal that the proposed algorithm achieves high compression ratios with low level reconstruction error while preserving diagnostic information in the reconstructed ECG signal. The proposed algorithm also slightly outperforms others for the same test dataset.
