The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] CAN(742hit)

61-80hit(742hit)

  • In Situ Measurement of Radiated Emissions Based on Array Signal Processing and Adaptive Noise Cancellation

    Peng LI  Zhongyuan ZHOU  Mingjie SHENG  Qi ZHOU  Peng HU  

     
    PAPER-Electromagnetic Theory

      Vol:
    E102-C No:4
      Page(s):
    371-379

    This paper presents a method combining array signal processing and adaptive noise cancellation to suppress unwanted ambient interferences in in situ measurement of radiated emissions of equipment. First, the signals received by the antenna array are processed to form a main data channel and an auxiliary data channel. The main channel contains the radiated emissions of the equipment under test and the attenuated ambient interferences. The auxiliary channel only contains the attenuated ambient interferences. Then, the adaptive noise cancellation technique is used to suppress the ambient interferences based on the correlation of the interferences in the main and auxiliary channels. The proposed method overcomes the problem that the ambient interferences in the two channels of the virtual chamber method are not correlated, and realizes the suppression of multi-source ambient noises in the use of fewer array elements. The results of simulation and experiment show that the proposed method can effectively extract radiated emissions of the equipment under test in complex electromagnetic environment. Finally, discussions on the effect of the beam width of the main channel and the generalization of the proposed method to three dimensionally distributed signals are addressed.

  • Designing and Implementing an Enhanced Bluetooth Low Energy Scanner with User-Level Channel Awareness and Simultaneous Channel Scanning

    Sangwook BAK  Young-Joo SUH  

     
    LETTER-Information Network

      Pubricized:
    2018/12/17
      Vol:
    E102-D No:3
      Page(s):
    640-644

    This paper proposes an enhanced BLE scanner with user-level channel awareness and simultaneous channel scanning to increase theoretical scanning capability by up to three times. With better scanning capability, channel analysis quality also has been improved by considering channel-specific signal characteristics, without the need of beacon-side changes.

  • Design of Criterion for Adaptively Scaled Belief in Iterative Large MIMO Detection Open Access

    Takumi TAKAHASHI  Shinsuke IBI  Seiichi SAMPEI  

     
    PAPER-Fundamental Theories for Communications

      Pubricized:
    2018/07/30
      Vol:
    E102-B No:2
      Page(s):
    285-297

    This paper proposes a new design criterion of adaptively scaled belief (ASB) in Gaussian belief propagation (GaBP) for large multi-user multi-input multi-output (MU-MIMO) detection. In practical MU detection (MUD) scenarios, the most vital issue for improving the convergence property of GaBP iterative detection is how to deal with belief outliers in each iteration. Such outliers are caused by modeling errors due to the fact that the law of large number does not work well when it is difficult to satisfy the large system limit. One of the simplest ways to mitigate the harmful impact of outliers is belief scaling. A typical approach for determining the scaling parameter for the belief is to create a look-up table (LUT) based on the received signal-to-noise ratio (SNR) through computer simulations. However, the instantaneous SNR differs among beliefs because the MIMO channels in the MUD problem are random; hence, the creation of LUT is infeasible. To stabilize the dynamics of the random MIMO channels, we propose a new transmission block based criterion that adapts belief scaling to the instantaneous channel state. Finally, we verify the validity of ASB in terms of the suppression of the bit error rate (BER) floor.

  • A 2-5GHz Wideband Inductorless Low Noise Amplifier for LTE and Intermediate-Frequency-Band 5G Applications

    Youming ZHANG  Fengyi HUANG  Lijuan YANG  Xusheng TANG  Zhen CHEN  

     
    LETTER

      Vol:
    E102-A No:1
      Page(s):
    209-210

    This paper presents a wideband inductorless noise-cancelling balun LNA with two gain modes, low NF, and high-linearity for LTE and intermediate-frequency-band (eg. 3.3-3.6GHz, 4.8-5GHz) 5G applications fabricated in 65nm CMOS. The proposed LNA is bonding tested and exhibits a minimum NF of 2.2dB and maximum IIP3 of -3.5dBm. Taking advantage of an off-chip bias inductor in CG stage and a cross-coupled buffer, the LNA occupies high operation frequency up to 5GHz with remarkable linearity and NF as well as compact area.

  • Side Scan Sonar Image Super Resolution via Region-Selective Sparse Coding

    Jaihyun PARK  Bonhwa KU  Youngsaeng JIN  Hanseok KO  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2018/10/22
      Vol:
    E102-D No:1
      Page(s):
    210-213

    Side scan sonar using low frequency can quickly search a wide range, but the images acquired are of low quality. The image super resolution (SR) method can mitigate this problem. The SR method typically uses sparse coding, but accurately estimating sparse coefficients incurs substantial computational costs. To reduce processing time, we propose a region-selective sparse coding based SR system that emphasizes object regions. In particular, the region that contains interesting objects is detected for side scan sonar based underwater images so that the subsequent sparse coding based SR process can be selectively applied. Effectiveness of the proposed method is verified by the reduced processing time required for image reconstruction yet preserving the same level of visual quality as conventional methods.

  • Low-Power Fifth-Order Butterworth OTA-C Low-Pass Filter with an Impedance Scaler for Portable ECG Applications

    Shuenn-Yuh LEE  Cheng-Pin WANG  Chuan-Yu SUN  Po-Hao CHENG  Yuan-Sun CHU  

     
    PAPER-Electronic Circuits

      Vol:
    E101-C No:12
      Page(s):
    942-952

    This study proposes a multiple-output differential-input operational transconductance amplifier-C (MODI OTA-C) filter with an impedance scaler to detect cardiac activity. A ladder-type fifth-orderButterworth low-pass filter with a large time constant and low noise is implemented to reduce coefficient sensitivity and address signal distortion. Moreover, linearized MODI OTA structures with reduced transconductance and impedance scaler circuits for noise reduction are used to achieve a wide dynamic range (DR). The OTA-based circuit is operated in the subthreshold region at a supply voltage of 1 V to reduce the power consumption of the wearable device in long-term use. Experimental results of the filter with a bandwidth of 250 Hz reveal that DR is 57.6 dB, and the harmonic distortion components are below -59 dB. The power consumption of the filter, which is fabricated through a TSMC 0.18 µm CMOS process, is lower than 390 nW, and the active area is 0.135 mm2.

  • A Novel Supervised Bimodal Emotion Recognition Approach Based on Facial Expression and Body Gesture

    Jingjie YAN  Guanming LU  Xiaodong BAI  Haibo LI  Ning SUN  Ruiyu LIANG  

     
    LETTER-Image

      Vol:
    E101-A No:11
      Page(s):
    2003-2006

    In this letter, we propose a supervised bimodal emotion recognition approach based on two important human emotion modalities including facial expression and body gesture. A effectively supervised feature fusion algorithms named supervised multiset canonical correlation analysis (SMCCA) is presented to established the linear connection between three sets of matrices, which contain the feature matrix of two modalities and their concurrent category matrix. The test results in the bimodal emotion recognition of the FABO database show that the SMCCA algorithm can get better or considerable efficiency than unsupervised feature fusion algorithm covering canonical correlation analysis (CCA), sparse canonical correlation analysis (SCCA), multiset canonical correlation analysis (MCCA) and so on.

  • Deep Convolutional Neural Networks for Manga Show-Through Cancellation

    Taku NAKAHARA  Kazunori URUMA  Tomohiro TAKAHASHI  Toshihiro FURUKAWA  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2018/08/02
      Vol:
    E101-D No:11
      Page(s):
    2844-2848

    Recently, the demand for the digitization of manga is increased. Then, in the case of an old manga where the original pictures have been lost, we have to digitize it from comics. However, the show-through phenomenon would be caused by scanning of the comics since it is represented as the double sided images. This letter proposes the manga show-through cancellation method based on the deep convolutional neural network (CNN). Numerical results show that the effectiveness of the proposed method.

  • Modified Generalized Sidelobe Canceller for Nonuniform Linear Array Radar Space-Time Adaptive Processing

    Xiang ZHAO  Zishu HE  Yikai WANG  Yuan JIANG  

     
    LETTER-Digital Signal Processing

      Vol:
    E101-A No:9
      Page(s):
    1585-1587

    This letter addresses the problem of space-time adaptive processing (STAP) for airborne nonuniform linear array (NLA) radar using a generalized sidelobe canceller (GSC). Due to the difficulty of determining the spatial nulls for the NLAs, it is a problem to obtain a valid blocking matrix (BM) of the GSC directly. In order to solve this problem and improve the STAP performance, a BM modification method based on the modified Gram-Schmidt orthogonalization algorithm is proposed. The modified GSC processor can achieve the optimal STAP performance and as well a faster convergence rate than the orthogonal subspace projection method. Numerical simulations validate the effectiveness of the proposed methods.

  • An Improved Spread Clutter Estimated Canceller for Main-Lobe Clutter Suppression in Small-Aperture HFSWR

    Di YAO  Xin ZHANG  Qiang YANG  Weibo DENG  

     
    LETTER-Digital Signal Processing

      Vol:
    E101-A No:9
      Page(s):
    1575-1579

    In small-aperture high frequency surface wave radar, the main-lobe clutter all can be seen as a more severe space spread clutter under the influence of the smaller array aperture. It compromises the detection performance of moving vessels, especially when the target is submerged in the clutter. To tackle this issue, an improved spread clutter estimated canceller, combining spread clutter estimated canceller, adaptive selection strategy of the optimal training samples and rotating spatial beam method, is presented to suppress main-lobe clutter in both angle domain and range domain. According to the experimental results, the proposed algorithm is shown to have far superior clutter suppression performance based on the real data.

  • Wide Angle Scanning Circular Polarized Meta-Structured Antenna Array

    Chang-Hyun LEE  Jeong-Hae LEE  

     
    PAPER-Antennas and Propagation

      Pubricized:
    2018/03/14
      Vol:
    E101-B No:9
      Page(s):
    2017-2023

    This paper presents a meta-structured circular polarized array antenna with wide scan angle. In order to widen the scanning angle of array antennas, this paper investigates unit antenna beamwidth and the coupling effects between array elements, both of which directly affect the steering performance. As a result, the optimal array distance, the mode configuration, and the antenna structure are elucidated. By using the features of the miniaturized mu-zero resonance (MZR) antenna, it is possible to design the antenna at optimum array distance for wide beamwidth. In addition, by modifying via position and gap configuration of the antenna, it is possible to optimize the mode configuration for optimal isolation. Finally, the 3dB steerable angle of 66° is successfully demonstrated using a 1x8 MZR CP antenna array without any additional decoupling structure. The measured beam patterns at a scan angle of 0°, 22°, 44°, and 66°agree well with the simulated beam patterns.

  • Fuzzy Levy-GJR-GARCH American Option Pricing Model Based on an Infinite Pure Jump Process

    Huiming ZHANG  Junzo WATADA  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2018/04/16
      Vol:
    E101-D No:7
      Page(s):
    1843-1859

    This paper focuses mainly on issues related to the pricing of American options under a fuzzy environment by taking into account the clustering of the underlying asset price volatility, leverage effect and stochastic jumps. By treating the volatility as a parabolic fuzzy number, we constructed a Levy-GJR-GARCH model based on an infinite pure jump process and combined the model with fuzzy simulation technology to perform numerical simulations based on the least squares Monte Carlo approach and the fuzzy binomial tree method. An empirical study was performed using American put option data from the Standard & Poor's 100 index. The findings are as follows: under a fuzzy environment, the result of the option valuation is more precise than the result under a clear environment, pricing simulations of short-term options have higher precision than those of medium- and long-term options, the least squares Monte Carlo approach yields more accurate valuation than the fuzzy binomial tree method, and the simulation effects of different Levy processes indicate that the NIG and CGMY models are superior to the VG model. Moreover, the option price increases as the time to expiration of options is extended and the exercise price increases, the membership function curve is asymmetric with an inclined left tendency, and the fuzzy interval narrows as the level set α and the exponent of membership function n increase. In addition, the results demonstrate that the quasi-random number and Brownian Bridge approaches can improve the convergence speed of the least squares Monte Carlo approach.

  • Digital Self-Interference Cancellation for LTE-Compatible In-Band Full-Duplex Systems

    Changyong SHIN  Jiho HAN  

     
    PAPER-Mobile Information Network and Personal Communications

      Vol:
    E101-A No:5
      Page(s):
    822-830

    In this paper, we present self-interference (SI) cancellation techniques in the digital domain for in-band full-duplex systems employing orthogonal frequency division multiple access (OFDMA) in the downlink (DL) and single-carrier frequency division multiple access (SC-FDMA) in the uplink (UL), as in the long-term evolution (LTE) system. The proposed techniques use UL subcarrier nulling to accurately estimate SI channels without any UL interference. In addition, by exploiting the structures of the transmitter imperfection and the known or estimated parameters associated with the imperfection, the techniques can further improve the accuracy of SI channel estimation. We also analytically derive the lower bound of the mean square error (MSE) performance and the upper bound of the signal-to-interference-plus-noise ratio (SINR) performance for the techniques, and show that the performance of the techniques are close to the bounds. Furthermore, by utilizing the SI channel estimates and the nonlinear signal components of the SI caused by the imperfection to effectively eliminate the SI, the proposed techniques can achieve SINR performance very close to the one in perfect SI cancellation. Finally, because the SI channel estimation of the proposed techniques is performed in the time domain, the techniques do not require symbol time alignment between SI and UL symbols.

  • Semi-Blind Interference Cancellation with Multiple Receive Antennas for MIMO Heterogeneous Networks

    Huiyu YE  Kazuhiko FUKAWA  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2017/11/10
      Vol:
    E101-B No:5
      Page(s):
    1299-1310

    Our previous work proposed a semi-blind single antenna interference cancellation scheme to cope with severe inter-cell interference in heterogeneous networks. This paper extends the scheme to allow multiple-receive-antenna implementation. It does not require knowledge of the training sequences of interfering signals and can cancel multiple interfering signals irrespective of the number of receive antennas. The proposed scheme applies an enhanced version of the quantized channel approach to suboptimal joint channel estimation and signal detection (JCESD) during the training period in order to blindly estimate channels of the interfering signals, while reducing the computational complexity of optimum JCESD drastically. Different from the previous work, the proposed scheme applies the quantized channel generation and local search at each individual receive antenna so as to estimate transmitted symbol matrices during the training period. Then, joint estimation is newly introduced in order to estimate a channel matrix from the estimated symbol matrices, which operates in the same manner as the expectation maximization (EM) algorithm and considers signals received at all receive antennas. Using the estimated channels, the proposed scheme performs multiuser detection (MUD) during the data period under the maximum likelihood (ML) criterion in order to cancel the interference. Computer simulations with two receive antennas under two-interfering-stream conditions show that the proposed scheme outperforms interference rejection combining (IRC) with perfect channel state information (CSI) and MUD with channels estimated by a conventional scheme based on the generalized Viterbi algorithm, and can achieve almost the same average bit error rate (BER) performance as MUD with channels estimated from sufficiently long training sequences of both the desired stream(s) and the interfering streams, while reducing the computational complexity significantly compared with full search involving all interfering signal candidates during the training period.

  • Accurate Estimation of Personalized Video Preference Using Multiple Users' Viewing Behavior

    Yoshiki ITO  Takahiro OGAWA  Miki HASEYAMA  

     
    PAPER-Image Processing and Video Processing

      Pubricized:
    2017/11/22
      Vol:
    E101-D No:2
      Page(s):
    481-490

    A method for accurate estimation of personalized video preference using multiple users' viewing behavior is presented in this paper. The proposed method uses three kinds of features: a video, user's viewing behavior and evaluation scores for the video given by a target user. First, the proposed method applies Supervised Multiview Spectral Embedding (SMSE) to obtain lower-dimensional video features suitable for the following correlation analysis. Next, supervised Multi-View Canonical Correlation Analysis (sMVCCA) is applied to integrate the three kinds of features. Then we can get optimal projections to obtain new visual features, “canonical video features” reflecting the target user's individual preference for a video based on sMVCCA. Furthermore, in our method, we use not only the target user's viewing behavior but also other users' viewing behavior for obtaining the optimal canonical video features of the target user. This unique approach is the biggest contribution of this paper. Finally, by integrating these canonical video features, Support Vector Ordinal Regression with Implicit Constraints (SVORIM) is trained in our method. Consequently, the target user's preference for a video can be estimated by using the trained SVORIM. Experimental results show the effectiveness of our method.

  • Nuclei Detection Based on Secant Normal Voting with Skipping Ranges in Stained Histopathological Images

    XueTing LIM  Kenjiro SUGIMOTO  Sei-ichiro KAMATA  

     
    PAPER-Biological Engineering

      Pubricized:
    2017/11/14
      Vol:
    E101-D No:2
      Page(s):
    523-530

    Seed detection or sometimes known as nuclei detection is a prerequisite step of nuclei segmentation which plays a critical role in quantitative cell analysis. The detection result is considered as accurate if each detected seed lies only in one nucleus and is close to the nucleus center. In previous works, voting methods are employed to detect nucleus center by extracting the nucleus saliency features. However, these methods still encounter the risk of false seeding, especially for the heterogeneous intensity images. To overcome the drawbacks of previous works, a novel detection method is proposed, which is called secant normal voting. Secant normal voting achieves good performance with the proposed skipping range. Skipping range avoids over-segmentation by preventing false seeding on the occlusion regions. Nucleus centers are obtained by mean-shift clustering from clouds of voting points. In the experiments, we show that our proposed method outperforms the comparison methods by achieving high detection accuracy without sacrificing the computational efficiency.

  • Semi-Blind Interference Cancellation with Single Receive Antenna for Heterogeneous Networks

    Huiyu YE  Kazuhiko FUKAWA  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2017/06/28
      Vol:
    E101-B No:1
      Page(s):
    232-241

    In order to cope with severe interference in heterogeneous networks, this paper proposes a semi-blind interference cancellation scheme, which does not require multiple receive antennas or knowledge about training sequences of the interfering signals. The proposed scheme performs joint channel estimation and signal detection (JCESD) during the training period in order to blindly estimate channels of the interfering signals. On the other hand, maximum likelihood detection (MLD), which can be considered the optimum JCESD, must perform channel estimation for all transmitted signal candidates of the interfering signals and must search for the most likely signal candidate. Therefore, MLD incurs a prohibitive amount of computational complexity. To reduce such complexity drastically, the proposed scheme enhances the quantized channel approach, and applies the enhanced version to JCESD. In addition, a recalculation scheme is introduced to avoid inaccurate channel estimates due to local minima. Using the estimated channels, the proposed scheme performs multiuser detection (MUD) of the data sequences in order to cancel the interference. Computer simulations show that the proposed scheme outperforms a conventional scheme based on the Viterbi algorithm, and can achieve almost the same average bit error rate performance as the MUD with channels estimated from sufficiently long training sequences of both the desired signal and the interfering signals, while reducing the computational complexity significantly compared with full search involving all interfering signal candidates during the training period.

  • New Generalized Sidelobe Canceller with Denoising Auto-Encoder for Improved Speech Enhancement

    Minkyu SHIN  Seongkyu MUN  David K. HAN  Hanseok KO  

     
    LETTER-Speech and Hearing

      Vol:
    E100-A No:12
      Page(s):
    3038-3040

    In this paper, a multichannel speech enhancement system which adopts a denoising auto-encoder as part of the beamformer is proposed. The proposed structure of the generalized sidelobe canceller generates enhanced multi-channel signals, instead of merely one channel, to which the following denoising auto-encoder can be applied. Because the beamformer exploits spatial information and compensates for differences in the transfer functions of each channel, the proposed system is expected to resolve the difficulty of modelling relative transfer functions consisting of complex numbers which are hard to model with a denoising auto-encoder. As a result, the modelling capability of the denoising auto-encoder can concentrate on removing the artefacts caused by the beamformer. Unlike conventional beamformers, which combine these artefacts into one channel, they remain separated for each channel in the proposed method. As a result, the denoising auto-encoder can remove the artefacts by referring to other channels. Experimental results prove that the proposed structure is effective for the six-channel data in CHiME, as indicated by improvements in terms of speech enhancement and word error rate in automatic speech recognition.

  • Performance Analysis of the Generalized Sidelobe Canceller in Finite Sample Size and Correlative Interference Situations

    Xu WANG  Julan XIE  Zishu HE  Qi ZHANG  

     
    PAPER-Digital Signal Processing

      Vol:
    E100-A No:11
      Page(s):
    2358-2369

    In the scenario of finite sample size, the performance of the generalized sidelobe canceller (GSC) is still affected by the desired signal even if all signal sources are independent with each other. Firstly, the novel expression of weight vector of the auxiliary array is derived under the circumstances of finite sample size. Utilizing this new weight vector and considering the correlative interferences, the general expression for the interference cancellation ratio (CR) is developed. Then, the impacts of the CR performance are further analyzed for the parameters including the input signal-to-noise ratio (SNR), the auxiliary array size, the correlation coefficient between the desired signal and interference as well as the snapshots of the sample data, respectively. Some guidelines can thus be given for the practical application. Numerical simulations demonstrate the agreement between the simulation results and the analytical results.

  • An Iterative Cancellation Technique for Adjacent Channel Interference Induced by Amplifier Nonlinearity in 60GHz Band Wireless Communication Systems Open Access

    Noboru OSAWA  Shinsuke IBI  Seiichi SAMPEI  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2017/05/15
      Vol:
    E100-B No:11
      Page(s):
    2060-2069

    This paper proposes an iterative cancellation technique for adjacent channel interference (ACI), induced by amplifier nonlinearity in millimeter wave (mmW) communication systems. In mmW communications, a large spectrum leak is expected because of the amplifier nonlinearity, and such a spectrum leak disturbs multichannel utilization. In order to mitigate the ACI, iterative interference cancellation in the receiver side is designed in this paper. Typically, iterative interference cancellation is conducted by generating a soft replica of interference from the feedback of the decoder, and subtracting the replica from the received signals. In this case, the canceller must know the amplifier nonlinearity in order to regenerate a soft replica of ACI. In this paper, amplifier nonlinearity is estimated by subjecting the received pilot signals to polynomial regression. We reveal that using only pilot signals in estimating amplifier nonlinearity is insufficient for guaranteeing replica accuracy. To address this issue, the proposed scheme exploits the detected data sequence in the regression analysis. We demonstrate that the proposed ACI cancellation technique can effectively mitigate ACI in multichannel utilization.

61-80hit(742hit)