IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
Volume 6 , Issue 13
Showing 1-14 articles out of 14 articles from the selected issue
LETTER
  • Mohsen Radfar, Saadat Pourmozaffari
    2009 Volume 6 Issue 13 Pages 889-896
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    Delay optimization with considering effective parameters in the design, such as energy consumption, need an extra effort to achieve quick solutions. In this paper, by taking the requirements of current design processes into account for sake of simultaneously considering all of the effective parameters, in one hand, and also trying to use the privilege of Logical Effort method's extra speed, in the other hand, a new method for solving the equations optimization problems is represented. With providing an initial point based on Logical Effort method by Geometric Programming, the convergence rate of optimization algorithms can be greatly increased.
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  • Joung-Yeal Kim, Yoon-Suk Park, Young-Hyun Jun, Bai-Sun Kong
    2009 Volume 6 Issue 13 Pages 897-903
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    A new mixed-voltage I/O buffer having the characteristics of low-voltage operation and small-area realization is proposed. The proposed I/O buffer provides significantly reduced latency at low supply voltages by eliminating the voltage swing degradation at timing-critical nets. The buffer also provides smaller layout area by avoiding the use of dedicated extra circuits like dynamic gate-bias circuit (DGBC) and hot-carrier prevention circuits (HCPC) to cope with hot-carrier-induced gate-oxide reliability issue. Comparison results in an 80-nm CMOS process indicate that the proposed mixed-voltage I/O buffer achieves 73% reduction on buffer latency, 23% reduction on operating voltage, and 31% reduction on layout area as compared to conventional I/O buffers.
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  • K. J. Kim, S. Zhang, S. W. Nam
    2009 Volume 6 Issue 13 Pages 904-909
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    In this paper, an improved FastICA algorithm is proposed for blind source separation by using a sixth-order Newton's method for finding the solutions of the nonlinear equations much faster than other Newton-type iterative methods. In particular, the proposed method has comparable separation performance, fewer iterations, and faster convergence speed.
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  • Hee Jin Sohn
    2009 Volume 6 Issue 13 Pages 910-915
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    Multi-hypothesis tracking (MHT) is one efficient way of global localization. One of the advantages of MHT is that pose hypotheses are compact and reliable since they are obtained not by random sampling, but by matching sensor data and map. Matching process usually takes adequate computation time for simple environments; however, when the environment is crowed by many objects and the sensor data is highly cluttered, we need tremendous time only for generating pose hypotheses. In this paper, Vector Pattern Matching method is presented for hypothesis generation, which shows great efficiency over traditional methods.
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  • ShanGuo Quan, Hojin Ha, YoungYong Kim
    2009 Volume 6 Issue 13 Pages 916-922
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    This paper describes a distortion-aware cooperative relaying (DACR)scheme for distortion minimized video transmission over wireless video sensor networks. We first introduce a simple performance metric considering the different spatial and temporal error propagation effects existing in a video packet. Then, we propose the DACR algorithm which achieves gradual video quality degradation due to packet loss under conditions of limited channel resources. Experimental results show that the proposed scheme outperforms other existing scheme, and can also support optimal video quality for variable channel status.
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  • Reza Sadeghpour, Abdolreza Nabavi
    2009 Volume 6 Issue 13 Pages 923-929
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    This paper describes generation of ultra wideband (UWB) waveforms with adaptive notch frequencies and hence reduced interferences on narrow band systems; by composition of derivative pair of Gaussian pulse. It is shown, through analytical formulation and/or simulation, that the notch frequencies in the composite waveforms and the number of notches can be adjusted by changing the delay time between derivative pair. In particular, MATLAB simulation results are given for combination of 4th-4th, 4th-5th, and 5th-5th order derivatives, which illustrate the accuracy of the technique. The composite UWB waveforms are also generated by a low-power programmable DAC-based circuit, using a 0.13µm CMOS technology.
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  • Alireza Saberkari, Shahriar B. Shokouhi, Adib Abrishamifar
    2009 Volume 6 Issue 13 Pages 930-935
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    This paper presents a low voltage highly linear CMOS up conversion mixer based on current conveyor (CCII), which converts an input of 100MHz IF signal to an output of 2.4GHz RF signal. The linearity of the designed mixer is greatly enhanced by utilizing a fully differential current conveyor. The flipped voltage follower (FVF) technique is applied for decreasing the current conveyor nonideality and the nonlinear output resistance of its buffer. Folded cascode structure has been used in the proposed mixer to achieve low supply voltage operation and separate biasing current of local oscillator (LO) switching and transconductance stages of mixer for decreasing the noise level of switching pairs. Full transistor level simulation results performed by Cadence in AMS 0.35µm CMOS technology reveal high linearity of the proposed mixer after a FOM-based comparison which has achieved up to 13.32dBm IIP3, -1.34dBm P-1dB and 96.7dBm IIP2 with a conversion gain of 4.2dB while consumes only 1.2mW at supply voltage of 1V.
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  • Juwon Lee, Sungin Kang
    2009 Volume 6 Issue 13 Pages 936-942
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    The ubiquitous healthcare (u-healthcare) system refers to mobile healthcare that manages a user's health information; of critical importance in the healthcare system is the accuracy of the measured health data. However, in actual practice, the accuracy changes remarkably according to user motion artifacts in real life. Therefore, this study shows a simplified algorithm for real-time u-healthcare devices to detect the peak points in photoplethysmograph signals despite the existence of motion artifacts. The proposed algorithm consists of filter banks and fuzzy inference. In experiments to evaluate the performance of the proposed algorithm, we used several motion artifacts including finger and wrist movements, arm swinging, and walking; we then compared our results with the performances for the moving average (MA) and scaled Fourier linear combiner (SFLC) methods. The proposed method showed a better performance than the other methods in the experiment when detecting heartbeats.
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  • Masatsugu Higashinaka, Noriyuki Fukui, Hiroshi Kubo
    2009 Volume 6 Issue 13 Pages 943-948
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    We propose a generalized frequency division multiple access (GFDMA) scheme which realizes a low PAPR characteristic compared with OFDMA, maintaining the sufficient capability of the frequency scheduling. GFDMA transmits the data with one or more frequency resources which can be divided into several pieces in the frequency domain. We can adaptively configure GFDMA between PAPR-oriented configuration like as SC-FDMA and throughput-oriented configuration like as OFDMA, depending on requirements. We focus on the investigation on the PAPR characteristic of GFDMA. Computer simulation confirms that GFDMA has a low PAPR property compared with OFDMA, still keeping sufficient frequency resource allocation capability.
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  • Kazuoki Matsugatani, Kunio Sakakibara, Nobuyoshi Kikuma, Hiroshi Hiray ...
    2009 Volume 6 Issue 13 Pages 949-954
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    A novel planar microstrip array antenna is proposed and fabricated. This antenna is composed of one active or fed microstrip patch and two parasitic microstrip patches. Two parasitic patches are coupled with active patch via one-dimensional electromagnetic bandgap (1D-EBG) structures. 1D-EBG structures, maintaining the resonation of active patch, supply microwave power to parasitic patches then no feeding circuits are needed and compact antenna is realized. Because of enhancement of coupling between active and parasitic patches, this antenna performs high gain of 10.8 dBi at 5.8 GHz, comparable to ideal three active patch array.
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  • Hidenori Kuwakado, Shoichi Hirose
    2009 Volume 6 Issue 13 Pages 955-958
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    A Preneel-Govaerts-Vandewalle hash function with a prefix-free padding method (PF-PGV hash function) is a block-cipher-based iterative hash function. Chang et al. claimed that 16 PF-PGV hash functions were indifferentiable from a random oracle. This letter shows that 4 out of 16 PF-PGV hash functions are not indifferentiable from a random oracle.
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  • Saeed Saeedi, Mojtaba Atarodi
    2009 Volume 6 Issue 13 Pages 959-965
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    A technique for simultaneous cancellation of noise, second-order distortion and third-order distortion in CMOS LNAs is presented. The proposed LNA topology consists of a matching stage and two common-source amplifier stages, performing single-ended to differential signal conversion with balanced output. The second and third-order nonlinearity of the individual amplifiers as well as the distortion caused by the interaction between the stages are suppressed to achieve high IIP3. A method for intrinsic cancellation of the second-order interaction is employed to reduce the dependence of the IIP3 on the frequency spacing between the interfering signals in the two-tone test.
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  • Yoshitaka Kurosaka, Seita Iwahashi, Kyosuke Sakai, Eiji Miyai, Wataru ...
    2009 Volume 6 Issue 13 Pages 966-971
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    The band structure of three types of photonic crystals is studied. In these photonic crystals, the rotationally asymmetric V-shaped air holes are combined while changing their orientation. We find that the band structure is very sensitive to the method of combination. From this result, we can say that the periodical perturbation produced only by change of the air-hole orientation can change the band structure largely. This idea can be applied to many apprications such as lasers which have unique beam patterns.
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  • Somayeh Gholami, Hassan Hajghassem, A. R. Erfanian
    2009 Volume 6 Issue 13 Pages 972-978
    Published: 2009
    Released: July 10, 2009
    JOURNALS FREE ACCESS
    The current-voltage characteristics of PtSi/p-Si Schottky barrier diodes were investigated in the temperature range of 85-136K and their barrier height (Φb), ideality factor (n) and series resistance (Rs) were found to be strongly temperature-dependent. While n decreases, Φb increases with increasing temperature and the conventional activation energy plot deviates from linearity. These discrepancies from ideal thermionic emission theory is attributed to Schottky barrier inhomogeneities and the Schottky barrier inhomogeneities are shown to obey a single Gaussian distribution with a mean value of 0.4548eV and a standard deviation of 0.0607eV. The modified activation plot which takes into account the barrier height variations through the Gaussian distribution is acceptably linear and gives ($\overline{\phi_b}$) and A* as 0.4546eV and 31.47Acm-2K-2 respectively.
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