IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
Volume 7, Issue 13
Displaying 1-12 of 12 articles from this issue
LETTER
• Nasrudin Abd. Rahim, Hew Wooi Ping, Jafferi Jamaludin
2010 Volume 7 Issue 13 Pages 892-898
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
In this paper, an intelligent controller based on a novel self-tuning fuzzy logic framework for elevator control applications is presented. The proposed controller utilizes the measured performance data of the elevator control system i.e. average waiting time (AWT), to initiate self-tuning through the adjustment of the membership functions, and the modification of the rule set. The controller's adaptation to the system's environment that is based on the system's measured performance eliminates the heavy dependence on the predicted traffic patterns for adaptation. From computer simulation, the controller's effectiveness is satisfactorily verified.
• Sung Jim Lim, Seung-Hoon Chae, Sung Bum Pan
2010 Volume 7 Issue 13 Pages 899-905
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
Biometrics-based user authentication has several advantages over traditional password-based systems for standalone authentication applications. The fingerprint is evaluated as the most realistic alternative up to the present time in the perspectives of availability, accuracy and economy. However, serious problems may cause if fingerprint information stored for user authentication is used illegally by a different person since it cannot be changed freely as a password due to a limited number of fingers. Recently, research in fuzzy fingerprint vault system has been carried out actively to safely protect fingerprint information in a fingerprint authentication system. In this paper, we propose the FPGA-based fuzzy fingerprint vault system for real-time processing. Based on the experimental results, we confirmed that the proposed system takes 0.53 second with 36 real minutiae and 400 chaff minutiae.
• Farzan Jazayeri, Ahmad Sammak, Behjat Forouzandeh, Farshid Raissi
2010 Volume 7 Issue 13 Pages 906-912
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
A novel sub-threshold inverter based on nanoscale Field Effect Diode (FED) and a basic static CMOS inverter are investigated in this paper. Simulation results demonstrate that power consumption and Power Delay Product (PDP) of the sub-threshold inverter which is designed with nanoscale FED are 57.9% and 18.21% less than these factors in a comparable CMOS sub-threshold inverter. So the nanoscale FED scheme can provide better power efficiency than standard sub-threshold CMOS inverters.
• Chanil Park, Junbeom Hur, Kisuk Kweon, Hyunsoo Yoon
2010 Volume 7 Issue 13 Pages 913-919
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
Self-healing key distribution schemes for broadcast encryption are capable of recovering missed group keys and resisting a collusion attack of up to t revoked users. However, since previous schemes have been considered only m sessions, it does not suitable to support infinite sessions. In the paper, we propose an efficient δ-self healing key distribution scheme with revocation capability. The proposed scheme can support infinite sessions by updating the private key of users and supporting a partial revocation. The communication overhead of the proposed scheme is compared with several previous works.
• Seiichi Takamatsu, Sachio Murao, Nguyen Binh-Khiem, Eiji Iwase, Kiyosh ...
2010 Volume 7 Issue 13 Pages 920-924
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
We fabricated and demonstrated electrochromic voxel arrays for a three-dimensional (3D) display prototype. A voxel is a cubic display element of a 3D image. The voxels were constructed with ultraviolet-curable polymer on a substrate with a MEMS process and coated with poly-(3,4-ethylenedioxythiophene): poly-styrenesulfonate (PEDOT:PSS). The resultant substrates were stacked in three-dimensional space. The PEDOT:PSS color changes from transparent to blue when -1V is applied. The coloration of one voxel was observed from the top and side views, and the coloration of a 3 × 3 × 3 voxel array was also observed.
• M. Bashiri, Ch. Ghobadi, M. Kamyab Hesari, J. Nourinia
2010 Volume 7 Issue 13 Pages 925-930
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
A novel microstrip-fed parasitic-coupled monopole antenna is presented for WLAN/WiMAX applications. The proposed antenna is in compact size, provides good impedance-matching bandwidth and possesses nearly dipole-like radiation patterns, covering WLAN (2.4-2.5GHz and 4.9-5.85GHz) and WiMAX (2.3-2.7GHz and 3.5-3.8GHz) bands. Simulation and measurements results of the prototyped antenna are presented and discussed.
• Yongsam Moon
2010 Volume 7 Issue 13 Pages 931-935
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
A transmitter-side spread-spectrum clock generator (TX-SSCG) with a second-order ΔΣ modulator is proposed for a 6-Gbps Serial ATA. Mixed-mode simulations show that a second-order ΔΣ modulator in TX-SSCG reduces the random jitter component of the receiver-side tracking skew through quantization noise shaping. Deterministic jitter is reduced with the loop bandwidth of RXPLL. A 0.13-µm CMOS prototype chip shows that the transceiver operates at 6Gbps over an 8-m SATA cable in TX-SSCG on and off. With TX-SSCG on, the spectrum is down-spread with 11.7-dB peak reduction and 5000-ppm spread amount.
• Alireza Borhani, Soroush Akhlaghi
2010 Volume 7 Issue 13 Pages 936-942
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
A single transmit antenna broadcast channel (BC) with large (n) number of users in a Rayleigh fading environment is considered. It is assumed each user either receives the minimum rate constraint of Rmin or remains silent. Recently, it is shown that by applying a proper power allocation strategy, the maximum number of active users in such channel scales as $\\frac{\\log(\\log(n))}{R_{min}}$ in the asymptotic case of n → ∞. The main contribution of this paper is to derive the expected delay of the optimum power allocation strategy in terms of fairness maximization. Accordingly, it is shown the expected delay of this strategy behaves like $R_{min}\\frac{{n}\\log({n})}{\\log(\\log(n))}+\\omega\\big(\\frac{n}{\\log(\\log(n))}\\big)$, where the expected delay is defined as the minimum number of channel uses which guarantees each user receives at least one packet.
• Shingo Mandai, Toru Nakura, Makoto Ikeda, Kunihiro Asada
2010 Volume 7 Issue 13 Pages 943-948
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
We propose a 8bit two stage time-to-digital converter (TDC) using a time difference amplifier. The time resolution is 1.89ps, and DNL of 0.9 and INL of 1.0 are achieved in simulation assuming the standard 0.18um CMOS. To amplify the time residue of the first stage, the 16x cascaded time difference amplifier (TDA) using differential logic delay cells is employed. Time resolution of the proposed TDC becomes finer by employing the 16x cascaded TDA and the linearity is improved by using only one TDA in the two stage TDC instead of using a lot of TDAs.
• Seunghun Jang, Chan-ho Ahn, Dong Ku Kim
2010 Volume 7 Issue 13 Pages 949-955
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
We propose a joint matching and relay power allocation scheme based on an interference-free architecture for the multiuser multiple-input multiple-output (MIMO) broadcast relay channel. Instead of using brute-force search, we propose a matching scheme that assigns the better subchannels at the first hop to the destinations with lower power costs. It is shown that the proposed matching scheme is optimal for certain power allocation schemes. Simulation results show that proposed matching scheme combined with water-filling power allocation is nearly optimal for the joint optimization problem of matching and power allocation.
2010 Volume 7 Issue 13 Pages 956-963
Published: 2010
Released on J-STAGE: July 10, 2010
JOURNAL FREE ACCESS
A study of some reported LC quadrature voltagecontrolled oscillators (LC-QVCO) is performed in which it is shown that robustness of the quadrature oscillation varies depending on the coupling configuration. Next, a new superharmonic LC-QVCO is proposed in which the common source node in either of two identical crossconnected LC-VCOs is coupled via a capacitor to the node common between the two varactors in the LC tank of the other LC-VCO. In the proposed coupling configuration there exists a closed loop through which the second harmonic signals circulate. A qualitative argument is presented to justify the robustness of the quadrature nature of the proposed QVCO by applying the Barkhausen phase criterion to the second harmonic signals in the loop. Since the coupling devices are only two capacitors, no extra noise sources and power consumption are added to the core VCOs. A Monte Carlo simulation showed that the phase error of the proposed QVCO is no more than 1o. Also, generalizing this method to several numbers of VCOs in a loop, multiphase signals can be generated. The proposed circuits were designed using a 0.18-µm RF CMOS technology and simulation results are presented.