Arama Sonuçları

Listeleniyor 1 - 6 / 6
  • 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 Bin
    This 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
    NFC Loyal for enhancing loyalty services through Near Field Communication
    (Springer US, 2013-02) Özdenizci Köse, Büşra; Ok, Kerem; Coşkun, Vedat
    Near Field Communication (NFC) as an emerging technology is currently leveraged by large standardization efforts and tries to find a suitable ecosystem. NFC enabled mobile devices with integrated smart cards introduce compelling opportunities and new business models. Development of new standards such as secure element (SE), smart card, secure channel, as well as JavaCard enables creating new ecosystems using a concurrent multi application platform which takes advantage of GlobalPlatform standards. We proposed NFC Loyal, which maintains storage, retrieval, and sharing among payment and loyalty applications through our proposed structure, called as Secure Common Domain Management (SCDM) system. SCDM as a centralized database management system on the SE stores valuable information provided by payment applications and shares them with loyalty applications through a secure channel. The direct outcome of using NFC Loyal is the increase in repeat purchases of customers; as well as being a beneficial business plan realized among the payment firms, loyalty firms, and the card owner, resulting in a win-win business model. In this study, we describe NFC Loyal model with its technical infrastructure, and present the NFC Loyal model's life cycle management on SE.
  • Yayın
    A survey on Near Field Communication (NFC) technology
    (Springer, 2013-08) Coşkun, Vedat; Özdenizci Köse, Büşra; Ok, Kerem
    Near Field Communication (NFC) as a promising short range wireless communication technology facilitates mobile phone usage of billions of people throughout the world that offers diverse services ranging from payment and loyalty applications to access keys for offices and houses. Eventually NFC technology integrates all such services into one single mobile phone. NFC technology has emerged lately, and consequently not much academic source is available yet. On the contrary, due to its promising business case options, there will be an increasing amount of work to be studied in the very close future. This paper presents the concept of NFC technology in a holistic approach with different perspectives, including communication essentials with standards, ecosystem and business issues, applications, and security issues. Open research areas and further recommended studies in terms of academic and business point of view are also explored and discussed at the end of each major subject's subsection. This comprehensive survey will be a valuable guide for researchers and academicians as well as for business world interested in NFC technology.
  • Yayın
    Compression of ECG signals using variable-length classified vector sets and wavelet transforms
    (Springer International Publishing AG, 2012) Gürkan, Hakan
    In 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 Cem
    The 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 Levent
    We 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.