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441-460hit(1013hit)

  • Development of an Interference Canceller in Satellite Communications Using a Multi-Level Modulation with Superposed Transmission

    Shoko KURODA  Sho TANAKA  Shigeo NAOI  Yozo TAKEDA  Ryusuke MIYAMOTO  Takao HARA  Minoru OKADA  

     
    PAPER

      Vol:
    E92-B No:11
      Page(s):
    3354-3364

    This paper proposes an architecture of an interference canceller for satellite communications with super-posed transmission, which is applicable not only to QPSK but also to 16QAM transmission to get higher satellite capacity. We implement it as an FPGA-based prototype and verify its performance. We propose here to use a new method to measure the satellite round-trip delay using an extended matched filter (EMF), which can work in low C/N conditions such as 0 dB and under. Given this performance, our canceller can work in a network in which forward and reverse links have the same power level. The results of the laboratory tests for QPSK show that interference can be suppressed by about 30 dB and that the BER degradation due to the canceller was small enough for operation.

  • On the Condition of ε-Transmissible Joint Source-Channel Coding for General Sources and General Channels

    Ryo NOMURA  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    LETTER-Information Theory

      Vol:
    E92-A No:11
      Page(s):
    2936-2940

    The joint source-channel coding problem is considered. The joint source-channel coding theorem reveals the existence of a code for the pair of the source and the channel under the condition that the error probability is smaller than or equal to ε asymptotically. The separation theorem guarantees that we can achieve the optimal coding performance by using the two-stage coding. In the case that ε = 0, Han showed the joint source-channel coding theorem and the separation theorem for general sources and channels. Furthermore the ε-coding theorem (0 ≤ ε <1) in the similar setting was studied. However, the separation theorem was not revealed since it is difficult in general. So we consider the separation theorem in this setting.

  • A Fixed Point Theorem in Weak Topology for Successively Recurrent System of Set-Valued Mapping Equations and Its Applications

    Kazuo HORIUCHI  

     
    PAPER-Nonlinear Problems

      Vol:
    E92-A No:10
      Page(s):
    2554-2559

    Let us introduce n ( ≥ 2) mappings fi (i=1,,n ≡ 0) defined on reflexive real Banach spaces Xi-1 and let fi:Xi-1 → Yi be completely continuous on bounded convex closed subsets Xi-1(0) ⊂ Xi-1. Moreover, let us introduce n set-valued mappings Fi : Xi-1 Yi → Fc(Xi) (the family of all non-empty compact subsets of Xi), (i=1,,n ≡ 0). Here, we have a fixed point theorem in weak topology on the successively recurrent system of set-valued mapping equations:xi ∈ Fi(xi-1, fi(xi-1)), (i=1,,n ≡ 0). This theorem can be applied immediately to analysis of the availability of system of circular networks of channels undergone by uncertain fluctuations and to evaluation of the tolerability of behaviors of those systems.

  • Ultra-Wideband Indoor Double-Directional Channel Estimation Using Transformation between Frequency and Time Domain Signals

    Naohiko IWAKIRI  Takehiko KOBAYASHI  

     
    PAPER-Ultra Wideband System

      Vol:
    E92-A No:9
      Page(s):
    2159-2166

    This paper proposes an ultra-wideband double-directional spatio-temporal channel sounding technique using transformation between frequency- and time-domain (FD and TD) signals. Virtual antenna arrays, composed of omnidirectional antennas and scanners, are used for transmission and reception in the FD. After Fourier transforming the received FD signals to TD ones, time of arrival (TOA) is estimated using a peak search over the TD signals, and then angle of arrivals (AOA) and angle of departure (AOD) are estimated using a weighted angle histogram with a multiple signal classification (MUSIC) algorithm applied to the FD signals, inverse-Fourier transformed from the TD signals divided into subregions. Indoor channel sounding results validated that an appropriate weighting reduced a spurious level in the angle histogram by a factor of 0.1 to 0.2 in comparison with that of non-weighting. The proposed technique successfully resolved dominant multipath components, including a direct path, a single reflection, and a single diffraction, in line-of-sight (LOS) and non-LOS environments. Joint TOA and AOA/AOD spectra were also derived from the sounding signals. The spectra illustrated the dominant multipath components (agreed with the prediction by ray tracing) as clusters.

  • Cross-Domain Service Composition in OSGi Environments

    Choonhwa LEE  Seungjae LEE  Eunsam KIM  Wonjun LEE  

     
    LETTER-System Programs

      Vol:
    E92-D No:6
      Page(s):
    1316-1319

    This letter presents a new approach to provide inter-domain service compositions for OSGi environments. Our proposal of remote wire objects extends OSGi's wiring capability across the framework boundaries, so that even remote services can join in the composition. Hence, a better composition is made possible with a richer set of candidate services from foreign domains.

  • Packet Utility Based Packet Scheduling for OFDMA Networks with Heterogeneous Delay Requirements

    Gangming LV  Shihua ZHU  Zhimeng ZHONG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E92-B No:6
      Page(s):
    2336-2340

    A delay-oriented packet scheduling scheme is proposed for downlink OFDMA networks with heterogeneous delay requirements. Using a novel packet utility concept, the proposed algorithm can exploit diversity from traffic characteristics and requirements to improve delay performance for delay sensitive traffics. Besides, the proposal also shows good ability in balancing fairness and efficiency. Simulation results show that our proposal outperforms existing delay-oriented scheduling schemes in terms of both delay performance and spectrum efficiency.

  • Formation of Pd Nanodots Induced by Remote Hydrogen Plasma and Its Application to Floating Gate MOS Memories

    Kazuhiro SHIMANOE  Katsunori MAKIHARA  Mitsuhisa IKEDA  Seiichi MIYAZAKI  

     
    PAPER

      Vol:
    E92-C No:5
      Page(s):
    616-619

    We have studied the formation of Pd-nanodots on SiO2 from ultrathin Pd films being exposed to remote hydrogen plasma at room temperature, in which parameters such as the gas pressure and input power to generate H2 plasma and the Pd film thickness were selected to get some insights into surface migration of Pd atoms induced with atomic hydrogen irradiation and resultant agglomeration with cohesive action. The areal dot density was controlled in the range from 3.4 to 6.51011 cm - 2 while the dot size distribution was changed from 7 to 1.5 in average dot height with 40% variation in full-width at half maximum. We also fabricated MOS capacitors with a Pd-nanodots floating gate and confirmed the flat-band voltage shift in capacitance-voltage characteristic due to electron injection to and emission from the dots floating gate.

  • Incremental Unsupervised-Learning of Appearance Manifold with View-Dependent Covariance Matrix for Face Recognition from Video Sequences

    Lina  Tomokazu TAKAHASHI  Ichiro IDE  Hiroshi MURASE  

     
    PAPER-Pattern Recognition

      Vol:
    E92-D No:4
      Page(s):
    642-652

    We propose an appearance manifold with view-dependent covariance matrix for face recognition from video sequences in two learning frameworks: the supervised-learning and the incremental unsupervised-learning. The advantages of this method are, first, the appearance manifold with view-dependent covariance matrix model is robust to pose changes and is also noise invariant, since the embedded covariance matrices are calculated based on their poses in order to learn the samples' distributions along the manifold. Moreover, the proposed incremental unsupervised-learning framework is more realistic for real-world face recognition applications. It is obvious that it is difficult to collect large amounts of face sequences under complete poses (from left sideview to right sideview) for training. Here, an incremental unsupervised-learning framework allows us to train the system with the available initial sequences, and later update the system's knowledge incrementally every time an unlabelled sequence is input. In addition, we also integrate the appearance manifold with view-dependent covariance matrix model with a pose estimation system for improving the classification accuracy and easily detecting sequences with overlapped poses for merging process in the incremental unsupervised-learning framework. The experimental results showed that, in both frameworks, the proposed appearance manifold with view-dependent covariance matrix method could recognize faces from video sequences accurately.

  • One-Shot Voltage-Measurement Circuit Utilizing Process Variation

    Takumi UEZONO  Takashi SATO  Kazuya MASU  

     
    PAPER

      Vol:
    E92-A No:4
      Page(s):
    1024-1030

    A novel voltage measurement circuit which utilizes process variation is proposed. Using the proposed circuit, the voltage of a nonperiodic waveform at a particular time point can be accurately captured by a single clock pulse (one-shot measurement). The proposed circuit can be designed without compensation circuits against process variation, and thus occupies only a small area. An analytical expression of offset voltage for the comparator utilizing process variation (UPV-comparator), which plays a key role in the proposed circuit, is derived and design considerations for the proposed circuit are discussed. The circuit operation is confirmed through SPICE simulation using 90 nm CMOS device models. The -0.04 and -3 dB bandwidths (99% and 50% amplitudes) of the proposed circuit are about 10 MHz and far over 1 GHz, respectively. The circuit area is also estimated using an experimental layout.

  • Improvements in a Ferrite Core Permeability Dispersion Measurement Based on a Microstrip Line Method

    Atsushi KURAMOTO  Tomohiko KANIE  Masato ADACHI  Masashi KATO  Yuichi NORO  Takashi TAKEO  

     
    PAPER-Microwaves, Millimeter-Waves

      Vol:
    E92-C No:4
      Page(s):
    532-538

    In this work, errors in a ferrite core permeability dispersion measurement using a microstrip line (MSL) method, where three kinds of MSL circuits are used, are evaluated by both an electromagnetic simulation technique and experiments. The computer simulated results have shown that although the measurement errors decrease according to the diameter of the winding wire which passes through a sample ferrite core becomes larger, that is the spacing between the wire and the core gets narrower, a certain amount of error still remains. In order to overcome this problem and improve the measurement accuracy, a metal pipe electrically connected to a ground plane for shielding is placed around the wire of the non-magnetic core circuit which is one of the three MSL circuits noted above.

  • Enhancing Salt-and-Pepper Noise Removal in Binary Images of Engineering Drawing

    Hasan S. M. AL-KHAFFAF  Abdullah Z. TALIB  Rosalina Abdul SALAM  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E92-D No:4
      Page(s):
    689-704

    Noise removal in engineering drawing is an important operation performed before other image analysis tasks. Many algorithms have been developed to remove salt-and-pepper noise from document images. Cleaning algorithms should remove noise while keeping the real part of the image unchanged. Some algorithms have disadvantages in cleaning operation that leads to removing of weak features such as short thin lines. Others leave the image with hairy noise attached to image objects. In this article a noise removal procedure called TrackAndMayDel (TAMD) is developed to enhance the noise removal of salt-and-pepper noise in binary images of engineering drawings. The procedure could be integrated with third party algorithms' logic to enhance their ability to remove noise by investigating the structure of pixels that are part of weak features. It can be integrated with other algorithms as a post-processing step to remove noise remaining in the image such as hairy noise attached with graphical elements. An algorithm is proposed by incorporating TAMD in a third party algorithm. Real scanned images from GREC'03 contest are used in the experiment. The images are corrupted by salt-and-pepper noise at 10%, 15%, and 20% levels. An objective performance measure that correlates with human vision as well as MSE and PSNR are used in this experiment. Performance evaluation of the introduced algorithm shows better-quality images compared to other algorithms.

  • What Can We See behind Sampling Theorems?

    Hidemitsu OGAWA  

     
    INVITED PAPER

      Vol:
    E92-A No:3
      Page(s):
    688-695

    This paper shows that there is a fruitful world behind sampling theorems. For this purpose, the sampling problem is reformulated from a functional analytic standpoint, and is consequently revealed that the sampling problem is a kind of inverse problem. The sampling problem covers, for example, signal and image restoration including super resolution, image reconstruction from projections such as CT scanners in hospitals, and supervised learning such as learning in artificial neural networks. An optimal reconstruction operator is also given, providing the best approximation to an individual original signal without our knowing the original signal.

  • On the Infimum and Supremum of Fuzzy Inference by Single Input Type Fuzzy Inference

    Hirosato SEKI  Hiroaki ISHII  

     
    PAPER-General Fundamentals and Boundaries

      Vol:
    E92-A No:2
      Page(s):
    611-617

    Fuzzy inference has played a significant role in many applications. Although the simplified fuzzy inference method is currently mostly used, the problem is that the number of fuzzy rules becomes very huge and so the setup and adjustment of fuzzy rules become difficult. On the other hand, Yubazaki et al. have proposed a "single input rule modules connected fuzzy inference method" (SIRMs method) whose final output is obtained by summarizing the product of the importance degrees and the inference results from single input fuzzy rule module. Seki et al. have shown that the simplified fuzzy inference method and the SIRMs method are equivalent when the sum of diagonal elements in rules of the simplified fuzzy inference method is equal to that of cross diagonal elements. This paper clarifies the conditions for the infimum and supremum of the fuzzy inference method using the single input type fuzzy inference method, from the view point of fuzzy inference.

  • Exploitation of Wireless Technology in Remote Care Processes Open Access

    Matti HAMALAINEN  Attaphongse TAPARUGSSANAGORN  Jari IINATTI  Ryuji KOHNO  

     
    INVITED PAPER

      Vol:
    E92-B No:2
      Page(s):
    373-378

    The average age of population is predicted to be raised universally but the number of nursing staff is not increasing at the same rate. This leads us to the situation where, e.g., we have too many patients for one nurse. On the other hand, sparse population in some regions, such as Northern or Eastern Finland, causes a severe problem that doctors are far away from patient. In this paper, we summarize the possibilities and applications that utilize wireless technologies in healthcare sector and which can be useful in nursing activities. The use of new innovations is one way to solve the problems that are based on the expected lack of professional staff in the future. Despite of the very natural hospital link, the developed technical solutions have applications outside hospital. Remote care of aging people and other special groups need to be done daily and almost real-time. Keeping people home instead of hospital is one way to decrease the entire care costs. In addition to the obvious human context, we derive some other applications where we can benefit wireless nursing and remote sensing techniques.

  • Vernier Caliper and Equivalent-Signal Sampling for Built-In Jitter Measurement System

    Shu-Yu JIANG  Chan-Wei HUANG  Yu-Lung LO  Kuo-Hsing CHENG  

     
    PAPER

      Vol:
    E92-A No:2
      Page(s):
    389-400

    Several problems in built-in-jitter-measurement (BIJM) system designs have been identified in recent years. The problems are associated with the external low-jitter sampling clock, chip area, timing resolution, or the measurement range via the process voltage temperature (PVT) variation effect. In this work, there are three proposed approaches and one conventioanl method that improve BIJM systems. For the system level, a proposed real equivalent-signal sampling technique is utilized to clear the requirement of the external low-jitter sampling clock. The proposed Vernier caliper structure is applied to reduce chip area cost for the designated timing resolution. At the circuit level, the proposed auto focus technique eliminates the PVT variation effect for the measurement range. The stepping scan technique is the conventional method that employed to minimize the area cost of counter circuits. All of these techniques were implemented in the 0.35 µm CMOS process. Furthermore, these techniques are successfully verified in 14 ps circuit resolution and a 500*750 µm chip area for the 100-400 MHz measurement range.

  • A Neural Network Based Algorithm for Particle Pairing Problem of PIV Measurements

    Achyut SAPKOTA  Kazuo OHMI  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E92-D No:2
      Page(s):
    319-326

    Particle Image Velocimetry (PIV) is a widely used tool for the measurement of the different kinematic properties of the fluid flow. In this measurement technique, a pulsed laser light sheet is used to illuminate a flow field seeded with tracer particles and at each instance of illumination, the positions of the particles are recorded on digital CCD cameras. The resulting two camera frames can then be processed by various techniques to obtain the velocity vectors. One such techniques involve the tracking of the individual particles so as to identify the displacement of the every particles present in the flow field. The displacement of individual particles thus determined gives the velocity information if divided by known time interval. The accuracy as well as efficiency of such measurement systems depend upon the reliability of the algorithms to track those particles. In the present work, a cellular neural network based algorithm has been proposed. Performance test has been carried out using the standard flow images. It performs well in comparison to the existing algorithms in terms of reliability, accuracy and processing time.

  • Constraint-Based Multi-Completion Procedures for Term Rewriting Systems

    Haruhiko SATO  Masahito KURIHARA  Sarah WINKLER  Aart MIDDELDORP  

     
    PAPER

      Vol:
    E92-D No:2
      Page(s):
    220-234

    In equational theorem proving, convergent term rewriting systems play a crucial role. In order to compute convergent term rewriting systems, the standard completion procedure (KB) was proposed by Knuth and Bendix and has been improved in various ways. The multi-completion system MKB developed by Kurihara and Kondo accepts as input a set of reduction orders in addition to equations and efficiently simulates parallel processes each of which executes the KB procedure with one of the given orderings. Wehrman and Stump also developed a new variant of completion procedure, constraint-based completion, in which reduction orders need not be given by using automated modern termination checkers. As a result, the constraint-based procedures simulate the execution of parallel KB processes in a sequential way, but naive search algorithms sometimes cause serious inefficiency when the number of the potential reduction orders is large. In this paper, we present a new procedure, called a constraint-based multi-completion procedure MKBcs, by augmenting the constraint-based completion with the framework of the multi-completion for suppressing the combinatorial explosion by sharing inferences among the processes. The existing constraint-based system SLOTHROP, which basically employs the best-first search, is more efficient when its built-in heuristics for process selection are appropriate, but when they are not, our system is more efficient. Therefore, both systems have their role to play.

  • A Robust Detection in the Case of Strong Narrowband Jammer with Unknown Nonstationary Power

    Victor GOLIKOV  Olga LEBEDEVA  

     
    LETTER-Communication Theory and Signals

      Vol:
    E92-A No:1
      Page(s):
    337-341

    We present likelihood-ratio test (LRT) for detecting a signal in the presence of a known colored clutter, a white noise and a strong jammer with unknown nonstationary power. We have suggested the test allowing to remove completely all components of the jammer. It has been obtained the asymptotic inverse covariance matrix of the clutter with the jammer when the jammer power tends to infinite. Using this formula we developed the asymptotic LRT detection test. The performance of the new test statistic is analyzed and compared with well known eigencanceler-based detector. The effect of the jammer removing on the performance is evaluated for an example scenario.

  • TE Plane Wave Reflection and Transmission from a Two-Dimensional Random Slab

    Yasuhiko TAMURA  

     
    PAPER

      Vol:
    E92-C No:1
      Page(s):
    77-84

    This paper reexamines reflection and transmission of a TE plane wave from a two-dimensional random slab discussed in the previous paper [IEICE Trans. Electron., Vol.E79-C, no.10, pp.1327-1333, October 1996] by means of the stochastic functional approach with the multiply renormalizing approximation. A random wavefield representation is explicitly shown in terms of a Wiener-Hermite expansion. The first-order incoherent scattering cross section and the optical theorem are numerically calculated. Enhanced scattering as gentle peaks or dips on the angular distribution of the incoherent scattering is reconfirmed in the directions of reflection and backscattering, and is newly found in the directions of forward scattering and 'symmetrical forward scattering.' The mechanism of enhanced scattering is deeply discussed.

  • Measurement Based MIMO Channel Capacity in an Urban Canyon Environment at the 3.7 GHz Band

    Jae-Woo LIM  Se-Woong KWON  Youn-Hyun PARK  Hyun-Goo YOON  Jong-Gwan YOOK  Yong-Joong YOON  

     
    LETTER-Antennas and Propagation

      Vol:
    E91-B No:12
      Page(s):
    4058-4061

    This paper describes the measurements made in an urban canyon environment of a relay network scenario to determine the capacity of the multiple-input-multiple-output (MIMO) channel. While varying antenna number and spacing, we measure the channel matrices in the 3.7 GHz band using a 44 switching MIMO channel sounder. The results show that antenna spacing is shown to have less impact than signal-to-noise (SNR) on MIMO channel capacity in a line-of-sight (LOS) environment when physical antenna spacing is selected at four wavelengths. As a result, in an urban MIMO LOS scenario, a base station can provide sufficient data throughput to relay station because most links from base station to relay station have LOS environment and are free from restriction of antenna spacing.

441-460hit(1013hit)