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[Keyword] FA(3430hit)

2181-2200hit(3430hit)

  • FEXT Cancellation Techniques for Multiuser DMT-VDSL Systems

    Jung-Soo WOO  Gi-Hong IM  Kyu-Min KANG  

     
    PAPER-Transmission Systems and Transmission Equipment

      Vol:
    E87-B No:1
      Page(s):
    1-9

    This paper discusses far-end crosstalk (FEXT) cancellation methods for multicarrier transmission system. A system arrangement and its tap update method are proposed when FEXT cancelers and a frequency-domain equalizer (FEQ) are jointly adapted to combat channel intersymbol interference, FEXT, and other additive noise. We present mathematical formulation of minimum mean-square error (MSE) and the optimum tap coefficients for the FEXT cancelers and the FEQ when FEXT cancellation techniques are introduced for multiuser discrete multitone (DMT) based very high-speed digital subscriber line (VDSL) transmission. It is shown that FEXT cancellation enhances the achievable bit rate in FEXT-limited systems. Computer simulation and analytical results show that the performance of jointly adapted FEXT cancelers and an FEQ is better than that of separately adapted FEXT cancelers and an FEQ.

  • Facial Parts Recognition by Hierarchical Tracking from Motion Image and Its Application

    Takuma FUNAHASHI  Tsuyoshi YAMAGUCHI  Masafumi TOMINAGA  Hiroyasu KOSHIMIZU  

     
    PAPER-Face

      Vol:
    E87-D No:1
      Page(s):
    129-135

    Faces of a person performing freely in front of the camera can be captured in a sufficient resolution for facial parts recognition by the proposed camera system enhanced with a special PTZ camera. Head region, facial parts regions such as eyes and mouth and the borders of facial parts are extracted hierarchically by being guided by the irises and nostrils preliminarily extracted from the images of PTZ camera. In order to show the effectivity of this system, we proposed a possibility to generate the borders of facial parts of the face for the facial caricaturing and to introduce eye-contacting facial images which can eye-contact bilaterally with each other on the TV conference environment.

  • Bipolar Scan Waveform for Fast Address in AC Plasma Display Panel

    Ki-Duck CHO  Heung-Sik TAE  Sung-Il CHIEN  

     
    LETTER-Electronic Displays

      Vol:
    E87-C No:1
      Page(s):
    116-119

    A new bipolar scan waveform is proposed to increase the light emission duty factor by achieving the fast address in AC plasma display panel (AC-PDP). The new bipolar scan waveform consists of two-step scan pulse, which can separate the address discharge mode into two different discharge modes: a space charge generation mode and a wall charge accumulation mode. By adopting the new bipolar scan waveform, the light emission duty factor is increased considerably under the single scan ADS driving scheme due to the reduction of address time per single subfield.

  • A Note on the Lattice Factoring Method

    Tetsuya IZU  

     
    LETTER

      Vol:
    E87-A No:1
      Page(s):
    221-223

    In 1999, Boneh et al. proposed the Lattice Factoring Method (LFM) for the integer factoring problem for a composite of the form N = prq by employing the LLL-algorithm. Time complexity of LFM is measured by the number of calls of the LLL-algorithm. In the worst case, the number is 2log p for a certain constant c. In 2001, Uchiyama and Kanayama introduced a novel criterion and provided an improved algorithm which runs (2k-p)/|p-Nr+1| times faster (for certain constants k, Nr+1). In this letter, we note another practical improvement applicable to the original and the improved LFM, which enables to provide about 2 times speed-up.

  • A Fast RSA-Type Public-Key Primitive Modulo pkq Using Hensel Lifting

    Tsuyoshi TAKAGI  

     
    PAPER-Asymmetric Cipher

      Vol:
    E87-A No:1
      Page(s):
    94-101

    We propose a public-key primitive modulo pkq based on the RSA primitive. The decryption process of the proposed scheme is faster than those of two variants of PKCS #1 version 2.1, namely the RSA cryptosystem using Chinese remainder theorem (CRT) and the Multi-Prime RSA. The message M of the proposed scheme is decrypted from M mod pk and M mod q using the CRT, where we apply the Hensel lifting to calculate M mod pk from M mod p that requires only quadratic complexity ((log2p)2). Moreover, we propose a trick that avoids modular inversions used for the Hensel lifting, and thus the proposed algorithm can be computed without modular inversion. We implemented in software both the proposed scheme with 1024-bit modulus p2q and the 1024-bit Multi-Prime RSA for modulus p1p2p3, where p,q,p1,p2,p3 are 342 bits. The improvements of the proposed scheme over the Multi-Prime RSA are as follows: The key generation is about 49% faster, the decryption time is about 42% faster, and the total secret key size is 33% smaller.

  • An Equalization Technique for High-Speed-Mobile OFDM Systems in Rayleigh Multipath Channels

    Dongguo LI  Katsumi YAMASHITA  

     
    LETTER-Fundamental Theories

      Vol:
    E87-B No:1
      Page(s):
    158-160

    In mobile OFDM systems, sub-carriers orthogonality will be broken due to Doppler shift, and this results in inter-carrier interference (ICI). Many methods have been proposed to compensate for this, however, these methods won't be suitable for fast fading caused by high mobile speed. In this letter, we propose a novel sampling theorem based pilot symbol-aided technique which can not only estimate the channel fading envelope (CFE) accurately under high relative Doppler frequency (RDF) but also achieve lower BER than conventional methods. The validity of the proposed method is demonstrated by computer simulations.

  • Chip Interleaved Multicode DS-CDMA with MMSEC in A Fading Channel

    Takeshi ITAGAKI  Tomoki SAO  Deepshikha GARG  Fumiyuki ADACHI  

     
    PAPER-Wireless Communication Technology

      Vol:
    E87-B No:1
      Page(s):
    79-87

    Direct sequence code division multiple access (DS-CDMA) provides flexible data transmission in wide range of data rates by the use of orthogonal multicode multiplexing. In a multipath fading environment, the transmission performance of multicode DS-CDMA degrades as that of single code DS-CDMA does. Chip interleaving is known to improve the bit error rate (BER) performance of the single code transmission by altering the fading channel into severely time selective fading channel. However, this partially destroys orthogonality property among spreading codes and thus, significantly degrades the BER performance of multicode DS-CDMA. In this paper, we propose the joint use of chip interleaving and time-domain minimum mean square error combining (MMSEC) equalization to improve the multicode DS-CDMA transmission performance. It is confirmed by computer simulations that the joint use of chip interleaving and MMSEC equalization significantly improves the BER performance of multicode DS-CDMA and achieves better BER performance compared to the single code DS-CDMA using chip interleaving and maximal ratio combining (MRC).

  • Sequential Fusion of Output Coding Methods and Its Application to Face Recognition

    Jaepil KO  Hyeran BYUN  

     
    PAPER-Face

      Vol:
    E87-D No:1
      Page(s):
    121-128

    In face recognition, simple classifiers are frequently used. For a robust system, it is common to construct a multi-class classifier by combining the outputs of several binary classifiers; this is called output coding method. The two basic output coding methods for this purpose are known as OnePerClass (OPC) and PairWise Coupling (PWC). The performance of output coding methods depends on accuracy of base dichotomizers. Support Vector Machine (SVM) is suitable for this purpose. In this paper, we review output coding methods and introduce a new sequential fusion method using SVM as a base classifier based on OPC and PWC according to their properties. In the experiments, we compare our proposed method with others. The experimental results show that our proposed method can improve the performance significantly on the real dataset.

  • Robust Projection onto Normalized Eigenspace Using Relative Residual Analysis and Optimal Partial Projection

    Fumihiko SAKAUE  Takeshi SHAKUNAGA  

     
    PAPER-Reconstruction

      Vol:
    E87-D No:1
      Page(s):
    34-41

    The present paper reports a robust projection onto eigenspace that is based on iterative projection. The fundamental method proposed in Shakunaga and Sakaue and involves iterative analysis of relative residual and projection. The present paper refines the projection method by solving linear equations while taking noise ratio into account. The refinement improves both the efficiency and robustness of the projection. Experimental results indicate that the proposed method works well for various kinds of noise, including shadows, reflections and occlusions. The proposed method can be applied to a wide variety of computer vision problems, which include object/face recognition and image-based rendering.

  • Determining Consistent Global Checkpoints of a Distributed Computation

    Dakshnamoorthy MANIVANNAN  

     
    PAPER-Computer Systems

      Vol:
    E87-D No:1
      Page(s):
    164-174

    Determining consistent global checkpoints of a distributed computation has applications in the areas such as rollback recovery, distributed debugging, output commit and others. Netzer and Xu introduced the notion of zigzag paths and presented necessary and sufficient conditions for a set of checkpoints to be part of a consistent global checkpoint. This result also reveals that determining the existence of zigzag paths between checkpoints is crucial for determining consistent global checkpoints. Recent research also reveals that determining zigzag paths on-line is not possible. In this paper, we present an off-line method for determining the existence of zigzag paths between checkpoints.

  • Quadratic Surface Reconstruction from Multiple Views Using SQP

    Rubin GONG  Gang XU  

     
    PAPER-Image Processing, Image Pattern Recognition

      Vol:
    E87-D No:1
      Page(s):
    215-223

    We propose using SQP (Sequential Quadratic Programming) to directly recover 3D quadratic surface parameters from multiple views. A surface equation is used as a constraint. In addition to the sum of squared reprojection errors defined in the traditional bundle adjustment, a Lagrangian term is added to force recovered points to satisfy the constraint. The minimization is realized by SQP. Our algorithm has three advantages. First, given corresponding features in multiple views, the SQP implementation can directly recover the quadratic surface parameters optimally instead of a collection of isolated 3D points coordinates. Second, the specified constraints are strictly satisfied and the camera parameters and 3D coordinates of points can be determined more accurately than that by unconstrained methods. Third, the recovered quadratic surface model can be represented by a much smaller number of parameters instead of point clouds and triangular patches. Experiments with both synthetic and real images show the power of this approach.

  • 3D Human Whole Body Construction by Contour Triangulation

    Bon-Ki KOO  Young-Kyu CHOI  Sung-Il CHIEN  

     
    PAPER-Computer Graphics

      Vol:
    E87-D No:1
      Page(s):
    233-243

    In the past decade, significant effort has been made toward increasing the accuracy and robustness of three-dimensional scanning methods. In this paper, we present a new prototype vision system named 3D Model Studio, which has been built to reconstruct a complete 3D model in as less as a few minutes. New schemes for a probe calibration and a 3D data merging (axis consolidation) are employed. We also propose a new semi-automatic contour registration method to generate accurate contour model from 3D data points, along with a contour triangulation based surface reconstruction. Experimental result shows that our system works well for reconstructing a complete 3D surface model of a human body.

  • Mean Capacity of MIMO Systems over Rayleigh Fading Channel

    Chunyan GAO  Ming ZHAO  Shidong ZHOU  Yan YAO  

     
    LETTER-Terrestrial Radio Communications

      Vol:
    E86-B No:12
      Page(s):
    3642-3645

    Two important lemmas on the determinant of random matrixes are deduced in this paper. Then based on these results, expression for the mean capacity of MIMO system over Rayleigh fading channels is obtained. This expression requires little calculation and is simple and efficient compared with conventional methods, and furthermore, it gives an explicit relation on the mean capacity of MIMO systems with antenna numbers and the relation of mean capacity with signal to noise ratio (SNR). Accuracy of this theoretic formula has been verified by computer simulation.

  • A New Fast Image Retrieval Using the Condensed Two-Stage Search Method

    JungWon CHO  SeungDo JEONG  GeunSeop LEE  SungHo CHO  ByungUk CHOI  

     
    LETTER-Multimedia Systems

      Vol:
    E86-B No:12
      Page(s):
    3658-3661

    In a content-based image retrieval (CBIR) system, both the retrieval relevance and the response time are very important. This letter presents the condensed two-stage search method as a new fast image retrieval approach by making use of the property of Cauchy-Schwarz inequality. The method successfully reduces the overall processing time for similarity computation, while maintaining the same retrieval relevance as the conventional exhaustive search method. By the extensive computer simulations, we observe that the condensed two-stage search method is more effective as the number of images and dimensions of the feature space increase.

  • Design and Fabrication of Superconducting Double Spiral Filter

    Manabu KAI  Teru NAKANISHI  Akihiko AKASEGAWA  Kazunori YAMANAKA  

     
    PAPER-Passive(Filter)

      Vol:
    E86-C No:12
      Page(s):
    2417-2421

    This paper reports the design and fabrication of a miniaturized superconducting microstrip line filter using YBCO film on MgO. The filter's resonators are shaped in a double spiral, and the size of the resonators is optimized from the standpoint of the unloaded Q-factor. The 15-pole bandpass filter that has the center frequency of 1.95 GHz and the bandwidth of 20 MHz is designed in the size of 9.7 44 mm. The simulated S-parameter characteristics of the filter is corresponding to the initial design parameters. We fabricated the filter on an MgO substrate with a diameter of 2 inches. The filter had very sharp cutoff and a very low insertion loss of 0.14 dB.

  • Hybrid Concatenated Space-Time Coding Systems

    Bon-Jin KU  Jong-Moon CHUNG  Changeon KANG  

     
    LETTER-Fundamental Theories

      Vol:
    E86-B No:12
      Page(s):
    3614-3616

    The effects of hybrid concatenated space-time (HC-ST) codes applying iterative a posteriori probability (APP) decoding are investigated. The bit error rate (BER) and frame error rate (FER) performance of the iterative decoded hybrid Tarokh, Seshadri, Calderbank space-time (TSC ST) coded system under flat Rayleigh fading is analyzed. At the FER 10-2 level the results show that the serially concatenated space-time (SC-ST) codes provide a coding gain of 3 dB compared to the TSC ST codes, where an additional coding gain of 1 dB beyond the SC-ST code performance can be obtained applying the HC-ST coding topology.

  • A Novel Learning Algorithm Which Makes Multilayer Neural Networks Multiple-Weight-Fault Tolerant

    Itsuo TAKANAMI  Yasuhiro OYAMA  

     
    PAPER-Dependable Systems

      Vol:
    E86-D No:12
      Page(s):
    2536-2543

    We propose an efficient algorithm for making multi-layered neural networks (MLN) fault-tolerant to all multiple weight faults in a multi-dimensional interval by injecting intentionally two extreme multi-dimensional values in the interval into the weights of the selected multiple links in a learning phase. The degree of fault-tolerance to a multiple weight fault is measured by the number of essential multiple links. First, we analytically discuss how to choose effectively the multiple links to be injected, and present a learning algorithm for making MLNs fault tolerant to all multiple (i.e., simultaneous) faults in the interval defined by two multi-dimensional extreme points. Then it is proved that after the learning algorithm successfully finishes, MLNs become fault tolerant to all multiple faults in the interval. It is also shown that the time in a weight modification cycle depends little on multiplicity of faults k for small k. These are confirmed by simulation.

  • An Efficiently Self-Reconstructing Array System Using E-1-Track Switches

    Tadayoshi HORITA  Itsuo TAKANAMI  

     
    PAPER-Fault Tolerance

      Vol:
    E86-D No:12
      Page(s):
    2743-2752

    The E-1-track switch torus array model and the "EAR" reconfiguration method are proposed for fault tolerance of mesh or torus-connected processor arrays, where the original idea of EAR is in EAM. The comparison among these and others is described in terms of the (run-time) array reliability, hardware overhead, and/or reconfiguration time. When a designer chooses one among fault tolerant methods, he should consider their features synthetically case by case, and we consider that the results given by this paper are useful for the choice.

  • A Three-tier Active Replication Protocol for Large Scale Distributed Systems

    Carlo MARCHETTI  Sara Tucci PIERGIOVANNI  Roberto BALDONI  

     
    PAPER-Dependable Software

      Vol:
    E86-D No:12
      Page(s):
    2544-2552

    The deployment of server replicas of a service across an asynchronous distributed system (e.g., Internet) is a real practical challenge. This target cannot be indeed achieved by classical software replication techniques (e.g., passive and active replication) as these techniques usually rely on group communication toolkits that require server replicas to run over a partially synchronous distributed system to solve the underlying agreement problem. This paper proposes a three-tier architecture for software replication that encapsulates the need of partial synchrony in a specific software component of a mid-tier to free replicas and clients from the need of underlying partial synchrony assumptions. Then we propose how to specialize the mid-tier in order to manage active replication of server replicas.

  • An Alternative Test Generation for Path Delay Faults by Using Ni-Detection Test Sets

    Hiroshi TAKAHASHI  Kewal K. SALUJA  Yuzo TAKAMATSU  

     
    PAPER-Test

      Vol:
    E86-D No:12
      Page(s):
    2650-2658

    In this paper, we propose an alternative method that does not generate a test for each path delay fault directly to generate tests for path delay faults. The proposed method generates an N-propagation test-pair set by using an Ni-detection test set for single stuck-at faults. The N-propagation test-pair set is a set of vector pairs which contains N distinct vector pairs for every transition faults at a check point. Check points consist of primary inputs and fanout branches in a circuit. We do not target the path delay faults for test generation, instead, the N-propagation test-pair set is generated for the transition (both rising and falling) faults of check points in the circuit. After generating tests, tests are simulated to determine their effectiveness for singly testable path delay faults and robust path delay faults. Results of experiments on the ISCAS'85 benchmark circuits show that the N-propagation test-pair sets obtained by our method are effective in testing path delay faults.

2181-2200hit(3430hit)