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11501-11520hit(20498hit)

  • The Characteristic Generators for a Group Code

    Haibin KAN  Xuefei LI  Hong SHEN  

     
    LETTER-Coding Theory

      Vol:
    E89-A No:5
      Page(s):
    1513-1517

    In this letter, we discussed some properties of characteristic generators for a finite Abelian group code, proved that any two characteristic generators can not start (end) at the same position and have the same order of the starting (ending) components simultaneously, and that the number of all characteristic generators can be directly computed from the group code itself. These properties are exactly the generalization of the corresponding trellis properties of a linear code over a field.

  • A Steepest Descent Algorithm for M-Convex Functions on Jump Systems

    Kazuo MUROTA  Ken'ichiro TANAKA  

     
    PAPER

      Vol:
    E89-A No:5
      Page(s):
    1160-1165

    The concept of M-convex functions has recently been generalized for functions defined on constant-parity jump systems. The b-matching problem and its generalization provide canonical examples of M-convex functions on jump systems. In this paper, we propose a steepest descent algorithm for minimizing an M-convex function on a constant-parity jump system.

  • Control Performance of Discrete-Time Fuzzy Systems Improved by Neural Networks

    Chien-Hsing SU  Cheng-Sea HUANG  Kuang-Yow LIAN  

     
    PAPER-Systems and Control

      Vol:
    E89-A No:5
      Page(s):
    1446-1453

    A new control scheme is proposed to improve the system performance for discrete-time fuzzy systems by tuning control grade functions using neural networks. According to a systematic method of constructing the exact Takagi-Sugeno (T-S) fuzzy model, the system uncertainty is considered to affect the membership functions. Then, the grade functions, resulting from the membership functions of the control rules, are tuned by a back-propagation network. On the other hand, the feedback gains of the control rules are determined by solving a set of LMIs which satisfy sufficient conditions of the closed-loop stability. As a result, both stability guarantee and better performance are concluded. The scheme applied to a truck-trailer system is verified by satisfactory simulation results.

  • Inapproximability of the Edge-Contraction Problem

    Hideaki OTSUKI  Tomio HIRATA  

     
    LETTER

      Vol:
    E89-A No:5
      Page(s):
    1425-1427

    For a property π on graphs, the edge-contraction problem with respect to π is defined as a problem of finding a set of edges of minimum cardinality whose contraction results in a graph satisfying the property π. This paper gives a lower bound for the approximation ratio for the problem for any property π that is hereditary on contractions and determined by biconnected components.

  • Robust Blind Equalization Algorithms Based on the Constrained Maximization of a Fourth-Order Cumulant Function

    Kiyotaka KOHNO  Mitsuru KAWAMOTO  Asoke K. NANDI  Yujiro INOUYE  

     
    LETTER-Digital Signal Processing

      Vol:
    E89-A No:5
      Page(s):
    1495-1499

    The present letter deals with the blind equalization problem of a single-input single-output infinite impulse response (SISO-IIR) channel with additive Gaussian noise. To solve the problem, we propose a new criterion for maximizing constrainedly a fourth-order cumulant. The algorithms derived from the criterion have such a novel property that even if Gaussian noise is added to the output of the channel, an effective zero-forcing (ZF) equalizer can be obtained with as little influence of Gaussian noise as possible. To show the validity of the proposed criterion, some simulation results are presented.

  • Ultrathin HfOxNy Gate Insulator Formation by Electron Cyclotron Resonance Ar/N2 Plasma Nitridation of HfO2 Thin Films

    Shun-ichiro OHMI  Tomoki KUROSE  Masaki SATOH  

     
    PAPER-Si Devices and Processes

      Vol:
    E89-C No:5
      Page(s):
    596-601

    HfOxNy thin films formed by the electron cyclotron resonance (ECR) Ar/N2 plasma nitridation of HfO2 films were investigated for high-k gate insulator applications. HfOxNy thin films formed by the ECR Ar/N2 plasma nitridation (60 s) of 1.5-nm-thick HfO2 films, which were deposited on chemically oxidized Si(100) substrates, were found to be effective for suppressing interfacial layer growth or crystallization during postdeposition annealing (PDA) in N2 ambient. After 900 PDA of for 5 min in N2 ambient, it was found that HfSiON film with a relatively high dielectric constant was formed on the HfOxNy/Si interface by Si diffusion. An equivalent oxide thickness (EOT) of 2.0 nm and a leakage current density of 1.010-3 A/cm2 (at VFB-1 V) were obtained. The effective mobility of the fabricated p-channel metal-insulator-semiconductor field-effect transistor (MISFET) with the HfOxNy gate insulator was 50 cm2/Vs, and the gate leakage current of the MISFET with the HfOxNy gate insulator was found to be well suppressed compared with the MISFET with the HfO2 gate insulator after 900 PDA because of the nitridation of HfO2.

  • An Embedded 8b 240 MS/s 1.36 mm2 104 mW 0.18 µm CMOS ADC for DVDs with Dual-Mode Inputs

    Young-Jae CHO  Se-Won KIM  Kyung-Hoon LEE  Hee-Cheol CHOI  Young-Lok KIM  Seung-Hoon LEE  

     
    PAPER-Electronic Circuits

      Vol:
    E89-C No:5
      Page(s):
    636-641

    This work describes an 8b 240 MS/s CMOS ADC as one of embedded core circuits for high-performance displays based on low-noise on-chip references and dual-mode inputs with the requirements of limited pins, low power, and small size at high speed. The proposed ADC uses externally connected pins only for analog inputs, digital outputs, and supplies. The ADC employs (1) a two-step pipeline architecture to optimize power and chip size at the target sampling frequency of 240 MHz, (2) advanced bootstrapping techniques to achieve high signal bandwidth in the input SHA, and (3) RC filter-based on-chip current and voltage references to improve noise performance with a power-off function for portable applications. The prototype ADC is implemented in a 0.18 µm CMOS and simultaneously integrated in a DVD system with dual-mode inputs. The prototype ADC shows the measured DNL and INL within 0.49LSB and 0.69LSB, and the SNDR and SFDR exceeding 38 dB and 50 dB for inputs up to the Nyquist frequency at 240 MS/s. The ADC consumes 104 mW at 240 MS/s and an active die area is 1.36 mm2 .

  • How Much Does Color Information Help Optical Flow Computation?

    Naoya OHTA  Satoe NISHIZAWA  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E89-D No:5
      Page(s):
    1759-1762

    Optical flow is usually computed only on the basis of intensity information of images. Therefore, if we use color information in addition to the intensity, it is expected that more accurate optical flow can be computed. However, this intuition will be correct only when the following conditions are satisfied. First, the images should contain rich color variations. Moreover, it is also required that the image gradient of each color band differs in its direction. In this report, we empirically examined the difference of gradient directions on each band using 500 images, and evaluated quantitatively the advantage of using color information for optical flow computation.

  • A Fast Edge-Splitting Algorithm in Edge-Weighted Graphs

    Hiroshi NAGAMOCHI  

     
    PAPER

      Vol:
    E89-A No:5
      Page(s):
    1263-1268

    Let H be a graph with a designated vertex s, where edges are weighted by nonnegative reals. Splitting edges e={u,s} and e'={s,v} at s is an operation that reduces the weight of each of e and e' by a real δ>0 while increasing the weight of edge {u,v} by δ. It is known that all edges incident to s can be split off while preserving the edge-connectivity of H and that such a complete splitting is used to solve many connectivity problems. In this paper, we give an O(mn+n2log n) time algorithm for finding a complete splitting in a graph with n vertices and m edges.

  • Coding Floorplans with Fewer Bits

    Katsuhisa YAMANAKA  Shin-ichi NAKANO  

     
    PAPER

      Vol:
    E89-A No:5
      Page(s):
    1181-1185

    A naive coding of floorplans needs 2m bits for each floorplan. In this paper we give a new simple coding of floorplans, which needs only 5m/3 bits for each floorplan.

  • Transformation of a Parity-Check Matrix for a Message-Passing Algorithm over the BEC

    Naoto KOBAYASHI  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    PAPER

      Vol:
    E89-A No:5
      Page(s):
    1299-1306

    We propose transformation of a parity-check matrix of any low-density parity-check code. A code with transformed parity-check matrix is an equivalent of a code with the original parity-check matrix. For the binary erasure channel, performance of a message-passing algorithm with a transformed parity-check matrix is better than that with the original matrix.

  • An Enhanced Time-Domain Circuit Simulation Technique Based on LIM

    Hidemasa KUBOTA  Yuichi TANJI  Takayuki WATANABE  Hideki ASAI  

     
    LETTER-Numerical Analysis and Optimization

      Vol:
    E89-A No:5
      Page(s):
    1505-1506

    In this paper, we show the generalized method of the time-domain circuit simulation based on LIM. Our method is applicable to any structure of circuits by combination with the SPICE-like method. In order to show the validity and efficiency of our method, an example circuit is simulated and the proposed method is compared with the conventional ones.

  • Dimensioning Models of Shared Resources for Optical Packet Switching in Unbalanced Input/Output Traffic Scenarios

    Vincenzo ERAMO  Marco LISTANTI  Luca Silvio BOVO  

     
    PAPER-Switching for Communications

      Vol:
    E89-B No:5
      Page(s):
    1505-1516

    This paper compares selected Optical Packet Switching architectures that use the wavelength conversion technique to solve the packet contention problem. The architectures in question share wavelength converters, which are needed to wavelength translate arriving packets. This paper focuses on two architectures: the Shared Per Output Line (SPOL) and the Shared Per Input Line (SPIL) architectures, in which the wavelength converters are shared per output and input fiber respectively. The performance of the proposed architectures is evaluated for all the balance/unbalance combinations of input/output traffic. Packet loss probability is expressed as a function of the number of wavelength converters used, by means of analytical models validated by simulations. The results obtained show that the SPIL architecture, when compared to the SPOL architecture, allows for greater economies in terms of number of wavelength converters needed. While the performance of the two architectures tends to have similar values in a scenario with unbalanced input traffic and balanced output traffic, in unbalanced output traffic scenarios the SPIL architecture requires about 50% less wavelength converters than the SPOL architecture does, for a given packet loss probability.

  • Solving the Graph Planarization Problem Using an Improved Genetic Algorithm

    Rong-Long WANG  Kozo OKAZAKI  

     
    LETTER-Numerical Analysis and Optimization

      Vol:
    E89-A No:5
      Page(s):
    1507-1512

    An improved genetic algorithm for solving the graph planarization problem is presented. The improved genetic algorithm which is designed to embed a graph on a plane, performs crossover and mutation conditionally instead of probability. The improved genetic algorithm is verified by a large number of simulation runs and compared with other algorithms. The experimental results show that the improved genetic algorithm performs remarkably well and outperforms its competitors.

  • Construction of Classifiers by Iterative Compositions of Features with Partial Knowledge

    Kazuya HARAGUCHI  Toshihide IBARAKI  

     
    PAPER

      Vol:
    E89-A No:5
      Page(s):
    1284-1291

    We consider the classification problem to construct a classifier c:{0,1}n{0,1} from a given set of examples (training set), which (approximately) realizes the hidden oracle y:{0,1}n{0,1} describing the phenomenon under consideration. For this problem, a number of approaches are already known in computational learning theory; e.g., decision trees, support vector machines (SVM), and iteratively composed features (ICF). The last one, ICF, was proposed in our previous work (Haraguchi et al., (2004)). A feature, composed of a nonempty subset S of other features (including the original data attributes), is a Boolean function fS:{0,1}S{0,1} and is constructed according to the proposed rule. The ICF algorithm iterates generation and selection processes of features, and finally adopts one of the generated features as the classifier, where the generation process may be considered as embodying the idea of boosting, since new features are generated from the available features. In this paper, we generalize a feature to an extended Boolean function fS:{0,1,*}S{0,1,*} to allow partial knowledge, where * denotes the state of uncertainty. We then propose the algorithm ICF* to generate such generalized features. The selection process of ICF* is also different from that of ICF, in that features are selected so as to cover the entire training set. Our computational experiments indicate that ICF* is better than ICF in terms of both classification performance and computation time. Also, it is competitive with other representative learning algorithms such as decision trees and SVM.

  • A True 10-bit Data Driver LSI for HDTV TFT-LCDs

    Jin-Ho KIM  Oh-Kyong KWON  Byong-Deok CHOI  

     
    PAPER-Si Devices and Processes

      Vol:
    E89-C No:5
      Page(s):
    585-590

    We present our recent results of the 10-bit data driver LSI for 42-inch diagonal TFT-LCD TV with full HD format. To develop data driver LSIs for a true 10-bit TFT-LCD TV with full HD (19201080) format, small chip area, low power consumption, and output uniformity between channels are key problems that must be solved. By applying a two-stage DAC which combines 8-bit resistor-string DAC and 2-bit binary weighted capacitor DAC, the area increase is limited to only 30% compared to the area of 8-bit resistor-string DAC. The output deviation between channels is successfully limited within 5 mV and the driver LSI with 414 outputs consumes the maximum total current of 16 mA when driving 42-inch HDTV panel. We confirmed that the picture with 10-bit shades of gray is much more natural than that with 8-bit shades of gray.

  • Robust Fuzzy Integral Regulator Design for a Class of Affine Nonlinear Systems

    Tung-Sheng CHIANG  Chian-Song CHIU  Peter LIU  

     
    PAPER-Systems and Control

      Vol:
    E89-A No:4
      Page(s):
    1100-1107

    This paper proposes a robust fuzzy integral controller for output regulating a class of affine nonlinear systems subject to a bias reference to the origin. First, a common biased fuzzy model is introduced for a class of continuous/discrete-time affine nonlinear systems, such as dc-dc converters, robotic systems. Then, combining an integrator and parallel distributed compensators, the fuzzy integral regulator achieves an asymptotic regulation. Moreover, when considering disturbances or unstructured certainties, a virtual reference model is presented and provides a robust gain design via LMI techniques. In this case, H∞ performances is guaranteed. Note that the information regarding the operational point and bias terms are not required during the controller implementation. Thus, the controller can be applied to a multi-task regulation. Finally, three numerical simulations show the expected results.

  • Bandwidth Efficient MC-CDMA Transmission over Frequency Selective Fading Channel in 1xEV-DV System

    Chanho YOON  Jaekwon KIM  Heejung YU  Suk-Kyu LEE  Joonhyuk KANG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E89-B No:4
      Page(s):
    1451-1454

    In this letter, we propose a cdma2000 based MC-CDMA scheme which inherits the same architecture and bandwidth of forward link packet data channel of cdma2000 1x EV-DV. The system utilizes no cyclic prefix, and it uses the bandwidth efficient iterative technique [6] to recover cyclicity of OFDM symbol of the MC-CDMA system to achieve backward compatibility with 1x EV-DV system. We report that the link-level performance of our proposed system is significantly better than previous equalizer-based scheme [7] in frequency selective fading channels.

  • Entropy Based Associative Memory

    Masahiro NAKAGAWA  

     
    PAPER

      Vol:
    E89-A No:4
      Page(s):
    895-901

    In this paper, an entropy based associative memory model will be proposed and applied to memory retrievals with an orthogonal learning model to compare with the conventional model based on the quadratic Lyapunov functional to be minimized. In the present approach, the updating dynamics will be constructed on the basis of the entropy minimization strategy which may be reduced asymptotically to the above-mentioned autocorrelation dynamics as a special case. From numerical results, it will be found that the presently proposed novel approach realizes twice of the memory capacity in comparison with the autocorrelation based dynamics such as associatron.

  • A Control Scheme of a Digital Cable Television Network with Respect to Transmission of Viewer Responses to Interactive Broadcast Programs

    Yoshinori ROKUGO  Kazushi TAHARA  Joji MAEDA  Susumu ITOH  

     
    PAPER-Broadcast Systems

      Vol:
    E89-B No:4
      Page(s):
    1392-1404

    When digital broadcasting services are provided through cable television (CATV) networks, viewers watching interactive programs such as quizzes or auctions may respond to the program within a short period. If these responses are transmitted in the upstream channel of the CATV networks using TCP/IP, they will result in burst traffic. The numerous TCP connections will trigger congestion in the upstream transmission facilities and will cause a significant delay in conventional Internet services such as web-browsing. The present paper proposes a new method of controlling the CATV upstream channel to avoid such congestion. We introduce class-based queues at each cable TV station, in which each service class is related to a type of interactive service. The status of the queue is relayed to the cable modems of subscribers using a CATV-specific MAC protocol. This queue-status information is used to suspend further initiation of TCP connections at cable modems. As a result, the TCP connections will be arbitrated in the CATV network, while the delay of the response transmission is traded for smoothing of the burst traffic. We numerically evaluate the effect of the proposed method using the time distribution of responses to an actual quiz program. The results show that the proposed method successfully suppresses interference of the burst traffic with conventional best-effort services.

11501-11520hit(20498hit)