IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
Volume 6 , Issue 14
Showing 1-14 articles out of 14 articles from the selected issue
LETTER
  • Shih-Hsu Huang, Jheng-Fu Yeh, Chun-Hua Cheng
    2009 Volume 6 Issue 14 Pages 979-985
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    Power gating is recognized as a useful technique to reduce the leakage power of an idle functional unit. However, when the function unit is turned on, a sudden discharge, called surge current, is induced. If too many functional units are turned on simultaneously, the instantaneous accumulated surge current may lead to the malfunction of the circuit. In this paper, we point out the high-level synthesis (including operation scheduling and functional unit binding) has a great impact on the maximum surge current. Then, based on that observation, we propose an integer linear program (ILP) to formally draw up the surge current minimization problem in the high-level synthesis stage. Compared with the existing design flow, benchmark data show that our approach can significantly reduce the maximum surge current without any design overhead.
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  • Kwan-Hee Jo, Ji-Hye Bong, Kyeong-Sik Min
    2009 Volume 6 Issue 14 Pages 986-992
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    In this letter, a new read circuit with self-adjusted column pulse width is proposed for low-power applications of resistive memories. In the conventional read circuit, its column pulse width is determined by the worst-case value of the cell resistance variations thereby the pulse width being longer than required when the resistance variations are not in the worst case. In this paper, to alleviate power loss due to this long column pulse width, the column pulse width is self-adjusted according to the resistance variations thus unnecessary power loss being able to be reduced significantly. The power consumption during the read is expected to be less by 28.6% than the conventional circuit when the SET resistance is its mean value as large as 2kΩ . The Monte Carlo simulation also shows that the power consumption of the proposed circuit is reduced by 25% in average than the conventional.
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  • Daesung Moon, Sungju Lee, Yongwha Chung
    2009 Volume 6 Issue 14 Pages 993-999
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    The fuzzy fingerprint vault has been proposed for protecting the fingerprint template by adding a number of redundant features. Recently, a correlation attack that finds the real features using multiple fingerprint vaults has been introduced by several researches and should be solved for practical implementations. To avoid this correlation attack, we propose the Match-on-Card system based on the fuzzy fingerprint vault where the fingerprint matching is performed by an in-card processor, not an external card reader. Since the vault information is not released from the smart card, it is difficult for an attacker to take multiple fingerprint vaults. However, because of the limited resources (i.e., processing power and memory space) of the smart card, integrating fuzzy fingerprint vault into it is still an open challenge. To overcome this limitation, we propose the configurable fuzzy fingerprint vault based on a geometric hashing. Experimental results show that our approach can obtain much less memory requirements (i.e., 50KB) and faster execution time (i.e., 1.5sec) than the previous ones (i.e., 277KB, 6.6sec) without a significant degradation of the verification accuracy.
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  • Amit Kumar Mishra
    2009 Volume 6 Issue 14 Pages 1000-1005
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    Validation of automatic target recognition (ATR) algorithm needs huge amount of real data, which is mostly infeasible. Hence we need statistical separability indices (SI) to evaluate the performance of ATR algorithms using limited amount of data. In this paper we explain five such different SIs. For parametric classifiers, we use the classic Bhattacharya distance as the SI and propose a simpler modified Bhattacharya distance. For non-parametric schemes we use the classic geometrical SI and propose two new geometrical SIs, viz. modified geometrical SI and nearest neighbor based separability index. The utilities and implications of these SIs are demonstrated by using them in real ATR exercises.
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  • Amir Sabbagh Molahosseini, Chitra Dadkhah, Keivan Navi
    2009 Volume 6 Issue 14 Pages 1006-1012
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    In this paper, we propose an efficient hardware implementation of the reverse converter for the new five-moduli set {2n, 2n/2-1, 2n/2+1, 2n+1, 22n-1-1} for even n. The converter has a two-level architecture, and is based on combination of new Chinese remainder theorem 1 (New CRT-I) and mixed-radix conversion (MRC). The presented reverse converter has lower hardware requirements, and results in a significant reduction in the conversion delay, compared to the reverse converter of the latest introduced five-moduli set {2n-1, 2n, 2n+1, 2n-1-1, 2n+1-1} that has the same dynamic range as the proposed five-moduli set.
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  • Siti Azlida Ibrahim, Mohamad Yusoff Alias, Nurul Nadia Ahmad
    2009 Volume 6 Issue 14 Pages 1013-1018
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    Due to limited spectrum and increasing demand for wireless application, efficient use of wireless channel is becoming more important. In this paper, we propose a new approach of adaptive modulation to be employed in adaptive beamforming system to increase spectral efficiency while maintaining transmission quality. With a guarantee of bit error rate (BER) =10-2 and 10-4, our proposed method can achieve average throughput of 4bits/symbol at signal-to-noise ratio (SNR) = 16dB and 22dB, respectively.
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  • Jian Zhang, Shuguo Li
    2009 Volume 6 Issue 14 Pages 1019-1024
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    The existing cyclic convolution based on Fermat number transform(FNT) can't produce the same results as the conventional one based on fast Fourier transform (FFT) due to the impact of modular operation in many cases. To overcome the problem, this paper proposes a novel data-recovery algorithm (DRA) for the cyclic convolution based on FNT with transform kernel 2 or its integer power in the ordinary binary number system. Then an efficient data-recovery circuit (DRC) is designed to implement the algorithm in the diminished-1 number systems, involving parallel-prefix carry computation units. The DRA and the DRC can eliminate the impact of modular operation and make the cyclic convolution based on FNT produce the correct resulting sequences. Synthesis results show that delay and area of the n-bit DRC are both less than the ones of an n-bit parallel-prefix adder (PPA).
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  • Fumiaki Yamashita, Toshimasa Matsuoka, Takao Kihara, Isao Takobe, Hae- ...
    2009 Volume 6 Issue 14 Pages 1025-1031
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    A low-voltage complementary cross-coupled differential LC-VCO was investigated using simple modeling. The bias-controllability of the VCO provides a simple design for low-voltage operation. An analytical design approach realized a 5GHz VCO under a 0.5V supply voltage using a 90-nm digital CMOS process.
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  • Ifong Wu, Shinobu Ishigami, Kaoru Gotoh, Yasushi Matsumoto
    2009 Volume 6 Issue 14 Pages 1032-1038
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    Electric field probes with three orthogonal elements were calibrated from 1-6GHz by the standard field method in an anechoic chamber. A special jig was constructed for setting and calibrating a Δ-beam-type probe. Calibration factors of the probes were obtained for each element using this jig. To reflect the future revision of IEC 61000-4 series, uncertainty in the calibration factors was investigated to improve calibration quality and determine the factors affecting calibration. We found that fluctuation in the power transmitted from a high power amplifier and the imperfection of the anechoic chamber were the most important factors affecting uncertainty.
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  • Ko-Chi Kuo, Hsing-Hui Wu
    2009 Volume 6 Issue 14 Pages 1039-1044
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    A low voltage, highly linear, and tunable triode transconductor is presented. The proposed transconductor uses a two-stage amplifier to regulate drain-source voltage of input devices. Thereby, high linearity can be achieved. The proposed design is able to operate at low supply voltage. The linear input range can be obtained up to 1.5V at 1.8V supply voltage. The simulated total harmonic distortion is -61dB with 0.7Vpp input signal. The design uses TSMC 0.18µm CMOS technology and supply voltage is 1.8V. Simulation result shows that the tuning range of the proposed transconductor can be ranged from 220µA/V to 869µA/V.
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  • Naoteru Shigekawa, Suehiro Sugitani
    2009 Volume 6 Issue 14 Pages 1045-1050
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    The impact of forces due to the difference in mechanical stresses between the Schottky contacts and passivation films on the electrical properties of (0001) AlGaN/GaN Schottky diodes is numerically analyzed in the framework of the edge force model. The compressive (tensile) passivation films induce negative (positive) piezoelectric charges below the Schottky contacts in the GaN channels and bring forth onsets of the concentration of two-dimensional electron gas at shallower (deeper) bias voltages. The change in the bias voltages at the onset due to edge forces of ± 0.5GPa · µm is 1 or 2V for diodes with 0.5-µm Schottky contacts. This indicates that passivation films with the designed stress play a crucial role in controlling the threshold voltages of AlGaN/GaN HEMTs.
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  • Young-Ho Jung, Hongsun Park
    2009 Volume 6 Issue 14 Pages 1051-1056
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    This paper proposes an orthogonal pilot-aided channel estimation scheme for uplink (UL) orthogonal frequency division multiple access (OFDMA) systems. In the proposed method, the users utilizing adjacent UL subchannels in the frequency domain share some common pilot subcarriers by using orthogonal pilot patterns. In this way, each user can effectively use more pilot subcarriers and can improve the quality of channel estimation, especially for the data subcarriers located near the edges of a multiple access (MA) user subchannel in the frequency domain, and can offer a better bit error rate than user dedicated pilot allocations.
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  • Mehdi Fallahpour, David Megias
    2009 Volume 6 Issue 14 Pages 1057-1063
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    An audio watermarking technique in the frequency domain which takes advantage of interpolation is proposed. Interpolated FFT samples are used to generate imperceptible marks. The experimental results show that the suggested method has very high capacity (about 3kbps), without significant perceptual distortion (ODG about -0.5) and provides robustness against common audio signal processing such as echo, add noise, filtering, resampling and MPEG compression (MP3). Depending on the specific application, the tuning parameters could be selected adaptively to achieve even more capacity and better transparency.
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  • Jose Juan Garcia-Hernandez, Carolina Reta, Rene Cumplido, Claudia Fere ...
    2009 Volume 6 Issue 14 Pages 1064-1070
    Published: 2009
    Released: July 25, 2009
    JOURNALS FREE ACCESS
    The RDM-QIM algorithm has been proposed as a solution to the gain attack in QIM-based data hiding schemes. Several data hiding applications, such as broadcasting monitoring and live performance watermarking, requires a real-time multi-channel behavior. While Digital Signal Processors (DSP) have been used for implementing these schemes achieving real-time performance for audio signal processing, FPGAs offer the posibility of fully exploiting the inherent parallelism of this type of algorithms for more demanding applications. This letter presents an efficient FPGA implementation of RDM-QIM algorithm that overcomes a DSP-based implementation for more than two orders of magnitude and allows real-time multi-channel behavior.
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