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Yayın A survey of algorithms and architectures for H.264 sub-pixel motion estimation(World Scientific, 2012-05) Fatemi, Mohammad Reza Hosseiny; Ateş, Hasan Fehmi; Salleh, Rosli BinThis paper reviews recent state-of-the-art H. 264 sub-pixel motion estimation (SME) algorithms and architectures. First, H.264 SME is analyzed and the impact of its functionalities on coding performance is investigated. Then, design space of SME algorithms is explored representing design problems, approaches, and recent advanced algorithms. Besides, design challenges and strategies of SME hardware architectures are discussed and promising architectures are surveyed. Further perspectives and future prospects are also presented to highlight emerging trends and outlook of SME designs.Yayın RFT Based multiband matching network design with foster resonance sections(IEEE, 2015) Yıldız, Serkan; Aksen, Ahmet; Yarman, Bekir Sıddık BinboğaA new method for a multi band matching network design is introduced in this paper. Foster resonance sections are used to create transmission zeros. This effect brings gain degradation at Transducer Power Gain (TPG) of the matching circuit at assigned frequencies of resonance sections. Single matching problem is concerned. It has been shown that proposed method gives good control on creating multiband characteristics.Yayın Compression of ECG signals using variable-length classified vector sets and wavelet transforms(Springer International Publishing AG, 2012) Gürkan, HakanIn this article, an improved and more efficient algorithm for the compression of the electrocardiogram (ECG) signals is presented, which combines the processes of modeling ECG signal by variable-length classified signature and envelope vector sets (VL-CSEVS), and residual error coding via wavelet transform. In particular, we form the VL-CSEVS derived from the ECG signals, which exploits the relationship between energy variation and clinical information. The VL-CSEVS are unique patterns generated from many of thousands of ECG segments of two different lengths obtained by the energy based segmentation method, then they are presented to both the transmitter and the receiver used in our proposed compression system. The proposed algorithm is tested on the MIT-BIH Arrhythmia Database and MIT-BIH Compression Test Database and its performance is evaluated by using some evaluation metrics such as the percentage root-mean-square difference (PRD), modified PRD (MPRD), maximum error, and clinical evaluation. Our experimental results imply that our proposed algorithm achieves high compression ratios with low level reconstruction error while preserving the diagnostic information in the reconstructed ECG signal, which has been supported by the clinical tests that we have carried out.Yayın Comment on "storage and dissipation limits in resonant switched-capacitor converters"(Hindawi Ltd, 2018-10-31) Göknar, İzzet CemThe purpose of this note is (i) to point to a reference missing in the paper (Mayo-Maldonado et al., 2018) and (ii) to show that some of its content is covered in a more general setting by the results in that reference (Goknar, 1972).Yayın An analog integrated circuit beamformer for high-frequency medical ultrasound imaging(IEEE-INST Electrical Electronics Engineers Inc, 2012-10) Gürün, Gökçe; Zahorian, Jaime S.; Şişman, Alper; Karaman, Mustafa; Hasler, Paul E.; Değertekin, Fahrettin LeventWe designed and fabricated a dynamic receive beamformer integrated circuit (IC) in 0.35-mu m CMOS technology. This beamformer IC is suitable for integration with an annular array transducer for high-frequency (30-50 MHz) intravascular ultrasound (IVUS) imaging. The beamformer IC consists of receive preamplifiers, an analog dynamic delay-and-sum beamformer, and buffers for 8 receive channels. To form an analog dynamic delay line we designed an analog delay cell based on the current-mode first-order all-pass filter topology, as the basic building block. To increase the bandwidth of the delay cell, we explored an enhancement technique on the current mirrors. This technique improved the overall bandwidth of the delay line by a factor of 6. Each delay cell consumes 2.1-mW of power and is capable of generating a tunable time delay between 1.75 ns to 2.5 ns. We successfully integrated the fabricated beamformer IC with an 8-element annular array. Experimental test results demonstrated the desired buffering, preamplification and delaying capabilities of the beamformer.
