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[Keyword] system(3183hit)

2501-2520hit(3183hit)

  • Adaptive Control Design for Linear Time-Varying System Based on Internal Model Principle

    Koichi HIDAKA  Hiromitsu OHMORI  Akira SANO  

     
    PAPER-Systems and Control

      Vol:
    E82-A No:6
      Page(s):
    1047-1054

    In this paper, we propose a new adaptive control system design using internal model principle (IMP) for a bounded polynomial parameters. In this method, we regard time varying parameters as variable disturbance and design an estimating law used the internal model of the disturbance so that the law is able to rejected the effectness of the disturbance. Our method has the features that the tracking error can converge to zero. Furthermore, we give a sufficient condition for the stability based on a small-gain theorem. The condition shows that our proposed method relax the stability condition more than the conventional methods based on a passivity theorem. Finally, we contain a numerical simulation to show an effect of our system.

  • A Deterministic Model for UHF Radio Wave Propagation through Building Windows in Cellular Environments

    Honggang ZHANG  Taro HAYASHIDA  Takashi YOSHINO  Shiro ITO  Yoji NAGASAWA  

     
    PAPER-Antennas and Propagation

      Vol:
    E82-B No:6
      Page(s):
    944-950

    This paper develops a deterministic model for evaluating the influence of building windows upon the outdoor-to-indoor propagation path in cellular systems. This prediction model is based on the Aperture-field method of Huygens-Fresnel wave theory. Penetration losses and indoor signal characteristics are analyzed. It is found that the window frames of the building play an important role in determining the indoor field intensities. In order to verify this model's accuracy, numerical results are compared with measurement values. The calculations agree well with the measurements.

  • Imperfect Singular Solutions of Nonlinear Equations and a Numerical Method of Proving Their Existence

    Yuchi KANZAWA  Shin'ichi OISHI  

     
    PAPER-Nonlinear Problems

      Vol:
    E82-A No:6
      Page(s):
    1062-1069

    A new concept of "an imperfect singular solution" is defined as an approximate solution which becomes a singular solution by adding a suitable small perturbation to the original equations. A numerical method is presented for proving the existence of imperfect singular solutions of nonlinear equations with guaranteed accuracy. A few numerical examples are also presented for illustration.

  • Coterie for Generalized Mutual Exclusion Problem

    Shao Chin SUNG  Yoshifumi MANABE  

     
    PAPER-Computer Systems

      Vol:
    E82-D No:5
      Page(s):
    968-972

    This paper discusses the generalized mutual exclusion problem defined by H. Kakugawa and M. Yamashita. A set of processes shares a set of resources of an identical type. Each resource must be accessed by at most one process at any time. Each process may have different accessible resources. If two processes have no common accessible resource, it is reasonable to ensure a condition in resource allocation, which is called allocation independence in this paper, i. e. , resource allocation to those processes must be performed without any interference. In this paper, we define a new structure, sharing structure coterie. By using a sharing structure coterie, the resource allocation algorithm proposed by H. Kakugawa and M. Yamashita ensures the above condition. We show a necessary and sufficient condition of the existence of a sharing structure coterie. The decision of the existence of a sharing structure coterie for an arbitrary distributed system is NP-complete. Furthermore, we show a resource allocation algorithm which guarantees the above requirement for distributed systems whose sharing structure coteries do not exist or are difficult to obtain.

  • Fast Modular Inversion Algorithm to Match Any Operation Unit

    Tetsutaro KOBAYASHI  Hikaru MORITA  

     
    PAPER

      Vol:
    E82-A No:5
      Page(s):
    733-740

    Speeding up modular inversion is one of the most important subjects in the field of information security. Over the elliptic curve -- on the prime finite field in particular goals -- public-key cryptosystems and digital signature schemes frequently use modular inversion if affine coordinates are selected. In the regular computer environment, most data transmission via networks and data storage on memories as well as the operation set of processors are performed in multiples of eight bits or bytes. A fast modular multiplication algorithm that matches these operation units for DSP was proposed to accelerate the Montgomery method by Dusse and Kaliski. However, modular inversion algorithms were developed using bit by bit operation and so do not match the operation unit. This paper proposes two techniques for modular inversion that suits any arbitrary processing unit. The first technique proposes a new extended GCD procedure without any division. It can be constructed by the shifting, adding and multiplying operations, all of which a Montgomery modular arithmetic algorithm employs. The second technique can reduce the delay time of post processing in the modular inversion algorithm. In particular, it is of great use for the modular inversion defined in the Montgomery representation. These proposed techniques make modular inversion about 5. 5 times faster.

  • A Buffer Management Scheme with Scalable Priorities (SPAS) for Multi-QoS Services in ATM Switching Systems

    Jisoo PARK  Changhwan OH  JeeHwan AHN  Jeong-A LEE  Kiseon KIM  

     
    LETTER-Switching and Communication Processing

      Vol:
    E82-B No:4
      Page(s):
    655-659

    An ATM buffer management scheme with logically separated buffers is proposed to guarantee various Quality of Services such as CBR, rt-VBR, nrt-VBR, ABR, and UBR and to make efficient use of system resources in ATM switching systems. By assigning proper priorities based on the count indicator (CI) and the time indicator (TI), respectively, the scheme can afford ABR services without cell loss and real-time services with controllable delay.

  • A Complete Methodology for Electro-Mechanical Characterization of a CMOS Compatible MEMS Technology

    Laurent LATORRE  Pascal NOUET  

     
    PAPER

      Vol:
    E82-C No:4
      Page(s):
    582-588

    In this paper we present a complete methodology for efficient electro-mechanical characterization of a CMOS compatible MEMS technology. Using an original test structure, the so-called "U-shape cantilever beam," we are able to determine all mechanical characteristics of force sensors constituted with elementary beams in a given technology. A complete set of electro-mechanical relations for the design of Microsystems have also been developed.

  • Enhanced Resonance by Coupling and Summing in Sinusoidally Driven Chaotic Neural Networks

    Shin MIZUTANI  Takuya SANO  Katsunori SHIMOHARA  

     
    PAPER-Nonlinear Problems

      Vol:
    E82-A No:4
      Page(s):
    648-657

    Enhancement of resonance is shown by coupling and summing in sinusoidally driven chaotic neural networks. This resonance phenomenon has a peak at a drive frequency similar to noise-induced stochastic resonance (SR), however, the mechanism is different from noise-induced SR. We numerically study the properties of resonance in chaotic neural networks in the turbulent phase with summing and homogeneous coupling, with particular consideration of enhancement of the signal-to-noise ratio (SNR) by coupling and summing. Summing networks can enhance the SNR of a mean field based on the law of large numbers. Global coupling can enhance the SNR of a mean field and a neuron in the network. However, enhancement is not guaranteed and depends on the parameters. A combination of coupling and summing enhances the SNR, but summing to provide a mean field is more effective than coupling on a neuron level to promote the SNR. The global coupling network has a negative correlation between the SNR of the mean field and the Kolmogorov-Sinai (KS) entropy, and between the SNR of a neuron in the network and the KS entropy. This negative correlation is similar to the results of the driven single neuron model. The SNR is saturated as an increase in the drive amplitude, and further increases change the state into a nonchaotic one. The SNR is enhanced around a few frequencies and the dependence on frequency is clearer and smoother than the results of the driven single neuron model. Such dependence on the drive amplitude and frequency exhibits similarities to the results of the driven single neuron model. The nearest neighbor coupling network with a periodic or free boundary can also enhance the SNR of a neuron depending on the parameters. The network also has a negative correlation between the SNR of a neuron and the KS entropy whenever the boundary is periodic or free. The network with a free boundary does not have a significant effect on the SNR from both edges of the free boundaries.

  • The Mechanism for Scalable Registry System with Aggregatable Address Allocation on WIDE 6bone

    Yuji SEKIYA  Hiromi WAKAI  Shu NAKAMAE  Kenji HIROSE  Jun MURAI  

     
    PAPER

      Vol:
    E82-D No:4
      Page(s):
    888-895

    The change over from IPv4 to IPv6 entails a potential increase in the number of records that the Registry System must maintain. Currently, only a few Network Information Centers (NICs), controlled by Internet Assigned Number Authority (IANA), operate their Registry Systems. As they concentrates data into several Registry System, it is not scalable. This paper focuses on the scalability issue in a Registry System and Mie Advanced Registry System (MARS) is proposed. Through the collaboration of independent Registry Systems, MARS ensures data consistency as well as making it possible to access data managed by other Registry Systems. A prototype system of MARS is implemented, maintained and managed on the WIDE 6bone. Some lessen from the operation of MARS give also described.

  • Data Transfer Evaluation of Nomadic Data Consistency Model for Large-Scale Mobile Systems

    Masahiro KURODA  Ryoji ONO  Yoshiki SHIMOTSUMA  Takashi WATANABE  Tadanori MIZUNO  

     
    PAPER

      Vol:
    E82-D No:4
      Page(s):
    822-830

    The optimistic consistency scheme has been established with respect to data consistency and availability in distributed systems. The nomadic data consistency model using version vectors to support data versioning for data synchronization and concurrent conflict detection is suitable for an optimistic replication system that supports large-scale wireless networks. This paper describes the architecture and its data consistency model using data versioning and its access domain control targeted for nomadic data sharing systems, such as collaborative works using database and messaging, and the data transfer optimizations of the model. We evaluate our data versioning scheme comparing with a traditional data versioning and the data transfer optimization by estimation and measurement assuming a mobile worker's job. We generate arithmetic formulas for data transfer estimation using the optimizing techniques and apply them to large-scale data sharing configurations in which collaboration groups are dynamically formed and data is exchanged in each group. The data versioning with an access domain increases flexibility in data sharing configurations, such as mobile collaboration systems and client/server type mobile systems. We confirmed that the combination of the general optimizations and the access domain configurations based on our data consistency model is applicable for large-scale mobile data sharing systems.

  • Resonance in a Chaotic Neuron Model Driven by a Weak Sinusoid

    Shin MIZUTANI  Takuya SANO  Tadasu UCHIYAMA  Noboru SONEHARA  

     
    PAPER-Neural Networks

      Vol:
    E82-A No:4
      Page(s):
    671-679

    We show by numerical calculations that a chaotic neuron model driven by a weak sinusoid has resonance. This resonance phenomenon has a peak at a drive frequency similar to that of noise-induced stochastic resonance (SR). This neuron model was proposed from biological studies and shows a chaotic response when a parameter is varied. SR is a noise induced effect in driven nonlinear dynamical systems. The basic SR mechanism can be understood through synchronization and resonance in a bistable system driven by a subthreshold sinusoid plus noise. Therefore, background noise can boost a weak signal using SR. This effect is found in biological sensory neurons and obviously has some useful sensory function. The signal-to-noise ratio (SNR) of the driven chaotic neuron model is improved depending on the drive frequency; especially at low frequencies, the SNR is remarkably promoted. The resonance mechanism in the model is different from the noise-induced SR mechanism. This paper considers the mechanism and proposes possible explanations. Also, the meaning of chaos in biological systems based on the resonance phenomenon is considered.

  • Steady State Analysis of 2-D LMS Adaptive Filters Using the Independence Assumption

    Maha SHADAYDEH  Masayuki KAWAMATA  

     
    PAPER

      Vol:
    E82-A No:3
      Page(s):
    457-465

    In this paper, we consider the steady state mean square error (MSE) analysis for 2-D LMS adaptive filtering algorithm in which the filter's weights are updated along both vertical and horizontal directions as a doubly-indexed dynamical system. The MSE analysis is conducted using the well-known independence assumption. First we show that computation of the weight-error covariance matrix for doubly-indexed 2-D LMS algorithm requires an approximation for the weight-error correlation coefficients at large spatial lags. Then we propose a method to solve this problem. Further discussion is carried out for the special case when the input signal is white Gaussian. It is shown that the convergence in the MSE sense occurs for step size range that is significantly smaller than the one necessary for the convergence of the mean. Simulation experiments are presented to support the obtained analytical results.

  • Computational Sensors -- Vision VLSI

    Kiyoharu AIZAWA  

     
    INVITED SURVEY PAPER

      Vol:
    E82-D No:3
      Page(s):
    580-588

    Computational sensor (smart sensor, vision chip in other words) is a very small integrated system, in which processing and sensing are unified on a single VLSI chip. It is designed for a specific targeted application. Research activities of computational sensor are described in this paper. There have been quite a few proposals and implementations in computational sensors. Firstly, their approaches are summarized from several points of view, such as advantage vs. disadvantage, neural vs. functional, architecture, analog vs. digital, local vs. global processing, imaging vs. processing, new processing paradigms. Then, several examples are introduced which are spatial processings, temporal processings, A/D conversions, programmable computational sensors. Finally, the paper is concluded.

  • Recent Progress in Medical Image Processing-Virtualized Human Body and Computer-Aided Surgery

    Jun-ichiro TORIWAKI  Kensaku MORI  

     
    INVITED SURVEY PAPER

      Vol:
    E82-D No:3
      Page(s):
    611-628

    In this article we present a survey of medical image processing with the stress on applications of image generation and pattern recognition / understanding to computer aided diagnosis (CAD) and surgery (CAS). First, topics and fields of research in medical image processing are summarized. Second the importance of the 3D image processing and the use of virtualized human body (VHB) is pointed out. Thirdly the visualization and the observation methods of the VHB are introduced. In the forth section the virtualized endoscope system is presented from the viewpoint of the observation of the VHB with the moving viewpoints. The fifth topic is the use of VHB with deformation such as the simulation of surgical operation, intra-operative aids and image overlay. In the seventh section several topics on image processing methodologies are introduced including model generation, registration, segmentation, rendering and the use of knowledge processing.

  • Image Processing for Intelligent Transport Systems

    Shinji OZAWA  

     
    INVITED SURVEY PAPER

      Vol:
    E82-D No:3
      Page(s):
    629-636

    Image processing about the vehicle is considered in this paper. When a vehicle is in a factory, image processing is applied for design and inspection, and when vehicle is on the road image processing is useful for Intelligent Transport Systems, which recently have been developed widely. There have been many researches and implementations using image sensors to get information for traffic control and vehicle control. The image seen from camera located beside or upon the road can be used for vehicle detection, velocity of car or car group measurement, parking car detection, etc. Moreover the image seen from camera located in vehicle can be used for preceding car detection, measurement of the distance to preceding car, obstacle detection, lane detection, etc. In this paper, studies about Image Processing for vehicle on the road are described.

  • Iterative Methods for Dense Linear Systems on Distributed Memory Parallel Computers

    Muneharu YOKOYAMA  Takaomi SHIGEHARA  Hiroshi MIZOGUCHI  Taketoshi MISHIMA  

     
    PAPER

      Vol:
    E82-A No:3
      Page(s):
    483-486

    The Conjugate Residual method, one of the iterative methods for solving linear systems, is applied to the problems with a dense coefficient matrix on distributed memory parallel computers. Based on an assumption on the computation and communication times of the proposed algorithm for parallel computers, it is shown that the optimal number of processing elements is proportional to the problem size N. The validity of the prediction is confirmed through numerical experiments on Hitachi SR2201.

  • Unbiased Estimation of Symmetric Noncausal ARMA Parameters Using Lattice Filter

    Md. Mohsin MOLLAH  Takashi YAHAGI  

     
    LETTER-Digital Signal Processing

      Vol:
    E82-A No:3
      Page(s):
    543-547

    An unbiased estimation method for symmetric noncausal ARMA model parameters is presented. The proposed algorithm works in two steps: first, a spectrally equivalent causal system is identified by lattice whitening filter and then the equivalent noncausal system is reconstructed. For AR system with noise or ARMA system without noise, the proposed method does not need any iteration method nor any optimization procedure. An estimation method of noise variance when the observation is made in noisy situation is discussed. The potential capabilities of the algorithm are demonstrated by using some numerical examples.

  • A 1.9-GHz Direct Conversion Transmitter IC with Low Power On-Chip Frequency Doubler

    Shoji OTAKA  Ryuichi FUJIMOTO  Hiroshi TANIMOTO  

     
    PAPER

      Vol:
    E82-A No:2
      Page(s):
    313-319

    A direct conversion transmitter IC including a proposed frequency doubler, a quadrature modulator, and a 3-bit variable attenuator was fabricated using BiCMOS technology with fT of 12 GHz. This architecture employing frequency doubler is intended for realizing wireless terminals that are low in cost and small in size. The architecture is effective for reducing serious interference between PA and VCO by making the VCO frequency different from that of PA. The proposed frequency doubler comprises a current-driven 90 phase-shifter and an ECL-EXOR circuit for both low power operation and wide input power range of local oscillator (LO). The proposed frequency doubler keeps high output power even when rectangular wave from LO is applied owing to use of the current-driven 90 phase-shifter instead of a voltage-driven 90 phase-shifter. An LO leakage of less than -25 dBc, an image rejection ratio in excess of 45 dBc, and a maximum attenuation of 21 dB were measured. The transmitter IC successfully operates at LO power above -15 dBm and consumes 68 mA from 2.7 V power supply voltage. An active die size is 1.5 mm3 mm.

  • Design of Fully Balanced Analog Systems Based on Ordinary and/or Modified Single-Ended Opamps

    Zdzis taw CZARNUL  Tetsuro ITAKURA  Noriaki DOBASHI  Takashi UENO  Tetsuya IIDA  Hiroshi TANIMOTO  

     
    INVITED PAPER

      Vol:
    E82-A No:2
      Page(s):
    256-270

    The system architectures, which allow a high performance fully balanced (FB) system based on ordinary/modified single-ended opamps to be implemented, are investigated and the basic and general requirements are formulated. Two new methods of an FB analog system design, which contribute towards achieving both a high performance IC system implementation and a great reduction of the design time are presented. It is shown that a single-ended system based on any type of opamp (rail-to-rail, constant gm, etc. ), realized in any technology (CMOS, bipolar, BiCMOS, GaAs), can be easily and effectively converted to its FB counterpart in a very practical way. Using the proposed rules, any FB system implementation with opamps (data converter, modulator, filter, etc. ) requires only a single-ended system version design and the drawbacks related to a conventional FB system design are avoided. The principles of the design are pointed out and they are verified by experimental results.

  • Some Modifications of the Tournament Algorithm for the Mutual Exclusion Problem

    Yoshihide IGARASHI  Hironobu KURUMAZAKI  Yasuaki NISHITANI  

     
    PAPER-Algorithm and Computational Complexity

      Vol:
    E82-D No:2
      Page(s):
    368-375

    We propose two lockout-free (starvation-free) mutual exclusion algorithms for the asynchronous multi-writer/reader shared memory model. The first algorithm is a modification of the well-known tournament algorithm for the mutual exclusion problem. By the modification we can speed up the original algorithm. The running time of the modified algorithm from the entrance of the trying region to the entrance of the critical region is at most (n-1)c+O(nl), where n is the number of processes, l is an upper bound on the time between successive two steps of each process, and c is is an upper bound on the time that any user spends in the critical region. The second algorithm is a further modification of the first algorithm. It is designed so that some processes have an advantage of access to the resource over other processes.

2501-2520hit(3183hit)