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821-840hit(26286hit)

  • Critical Location of Communications Network with Power Grid Power Supply Open Access

    Hiroshi SAITO  

     
    PAPER-Network Management/Operation

      Pubricized:
    2022/08/10
      Vol:
    E106-B No:2
      Page(s):
    166-173

    When a disaster hits a network, network service disruptions can occur even if the network facilities have survived and battery and power generators are provided. This is because in the event of a disaster, the power supply will not be restarted within the lifetime of the battery or oil transportation will not be restarted before running out of oil and power will be running out. Therefore, taking a power grid into account is important. This paper proposes a polynomial-time algorithm to identify the critical location C*D of a communications network Nc when a disaster hits. Electrical power grid Np supplies power to the nodes of Nc, and a link in Nc is disconnected when a node or a link in Nc or Np fails. Here, the disaster area is modeled as co-centric disks and the failure probability is higher in the inner disk than the outer one. The location of the center of the disaster with the greatest expected number of disconnected links in Nc is taken as the critical location C*D.

  • Radial Line Planar Phased Array Using Electromechanically Rotated Helical Antennas

    Narihiro NAKAMOTO  Yusuke SUZUKI  Satoshi YAMAGUCHI  Toru FUKASAWA  Naofumi YONEDA  Hiroaki MIYASHITA  Naoki SHINOHARA  

     
    PAPER-Antennas and Propagation

      Pubricized:
    2022/08/10
      Vol:
    E106-B No:2
      Page(s):
    174-183

    In this paper, we propose a novel radial line planar phased array in which helical antenna elements are individually rotated by their respective connected micromotors to realize dynamic beam-scanning. To our knowledge, this is the first radial line planar array (RLPA) that has antenna elements electromechanically rotated by their individual micromotors. To facilitate its fabrication, helix and its probe are directly metallized on a plastic shaft using molded interconnect device technology, and a motor shaft is press-fitted into the plastic shaft. We also present a new design methodology for RLPA, which combines the equivalent circuit theory and electromagnetic simulations of the unit cell element. The proposed procedure is practical to design an RLPA of antenna elements with arbitrary probe shape without large-scale full-wave analysis of the whole structure of the RLPA. We design, fabricate, and evaluate a 7-circle array with 168 helical antenna elements fabricated using molded interconnect device technology. The prototype antenna exhibits dynamic and accurate beam-scanning performance. Furthermore, the prototype antenna exhibits a low reflection coefficient (less than -17dB) and high antenna efficiency (above 77%), which validates the proposed design methodology.

  • Suppression Effect of Randomly-Disturbed LC Alignment Fluctuation on Speckle Noise for Electronic Holography Imaging Open Access

    Masatoshi YAITA  Yosei SHIBATA  Takahiro ISHINABE  Hideo FUJIKAKE  

     
    INVITED PAPER

      Pubricized:
    2022/09/08
      Vol:
    E106-C No:2
      Page(s):
    26-33

    In this paper, we proposed the phase disturbing device using randomly-fluctuated liquid crystal (LC) alignment to reduce the speckle noise generated in holographic displays. Some parameters corresponding to the alignment fluctuation of thick LC layer were quantitatively evaluated, and we clarified the effect of the LC alignment fluctuation with the parameters on speckle noise reduction.

  • Novel Structure of Single-Shunt Rectifier Circuit with Impedance Matching at Output Filter

    Katsumi KAWAI  Naoki SHINOHARA  Tomohiko MITANI  

     
    PAPER-Microwaves, Millimeter-Waves

      Pubricized:
    2022/08/16
      Vol:
    E106-C No:2
      Page(s):
    50-58

    This study proposes a new structure of a single-shunt rectifier circuit that can reduce circuit loss and improve efficiency over the conventional structure. The proposed structure can provide impedance matching to the measurement system (or receiving antenna) without the use of conventional matching circuits, such as stubs and tapers. The proposed structure can simultaneously perform full-wave rectification and impedance matching by placing a feeding point on the output filter's λ/4 transmission line. We use circuit simulation to compare the RF-DC conversion efficiency and circuit loss of the conventional and proposed structures. The simulation results show that the proposed structure has lower circuit loss and higher RF-DC conversion efficiency than the conventional structure. We fabricate the proposed rectifier circuit using a GaAs Schottky barrier diode. The simulation and measurement results show that the single-shunt rectifier circuit's proposed structure is capable of rectification and impedance matching. The fabricated rectifier circuit's RF-DC conversion efficiency reaches a maximum of 91.0%. This RF-DC conversion efficiency is a world record for 920-MHz band rectifier circuits.

  • Commit-Based Class-Level Defect Prediction for Python Projects

    Khine Yin MON  Masanari KONDO  Eunjong CHOI  Osamu MIZUNO  

     
    PAPER

      Pubricized:
    2022/11/14
      Vol:
    E106-D No:2
      Page(s):
    157-165

    Defect prediction approaches have been greatly contributing to software quality assurance activities such as code review or unit testing. Just-in-time defect prediction approaches are developed to predict whether a commit is a defect-inducing commit or not. Prior research has shown that commit-level prediction is not enough in terms of effort, and a defective commit may contain both defective and non-defective files. As the defect prediction community is promoting fine-grained granularity prediction approaches, we propose our novel class-level prediction, which is finer-grained than the file-level prediction, based on the files of the commits in this research. We designed our model for Python projects and tested it with ten open-source Python projects. We performed our experiment with two settings: setting with product metrics only and setting with product metrics plus commit information. Our investigation was conducted with three different classifiers and two validation strategies. We found that our model developed by random forest classifier performs the best, and commit information contributes significantly to the product metrics in 10-fold cross-validation. We also created a commit-based file-level prediction for the Python files which do not have the classes. The file-level model also showed a similar condition as the class-level model. However, the results showed a massive deviation in time-series validation for both levels and the challenge of predicting Python classes and files in a realistic scenario.

  • A Comparative Study of Data Collection Periods for Just-In-Time Defect Prediction Using the Automatic Machine Learning Method

    Kosuke OHARA  Hirohisa AMAN  Sousuke AMASAKI  Tomoyuki YOKOGAWA  Minoru KAWAHARA  

     
    LETTER

      Pubricized:
    2022/11/11
      Vol:
    E106-D No:2
      Page(s):
    166-169

    This paper focuses on the “data collection period” for training a better Just-In-Time (JIT) defect prediction model — the early commit data vs. the recent one —, and conducts a large-scale comparative study to explore an appropriate data collection period. Since there are many possible machine learning algorithms for training defect prediction models, the selection of machine learning algorithms can become a threat to validity. Hence, this study adopts the automatic machine learning method to mitigate the selection bias in the comparative study. The empirical results using 122 open-source software projects prove the trend that the dataset composed of the recent commits would become a better training set for JIT defect prediction models.

  • Superposition Signal Input Decoding for Lattice Reduction-Aided MIMO Receivers Open Access

    Satoshi DENNO  Koki KASHIHARA  Yafei HOU  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2022/08/01
      Vol:
    E106-B No:2
      Page(s):
    184-192

    This paper proposes a novel approach to low complexity soft input decoding for lattice reduction-aided MIMO receivers. The proposed approach feeds a soft input decoder with soft signals made from hard decision signals generated by using a lattice reduction-aided linear detector. The soft signal is a weighted-sum of some candidate vectors that are near by the hard decision signal coming out from the lattice reduction-aided linear detector. This paper proposes a technique to adjust the weight adapt to the channel for the higher transmission performance. Furthermore, we propose to introduce a coefficient that is used for the weights in order to enhance the transmission performance. The transmission performance is evaluated in a 4×4 MIMO channel. When a linear MMSE filter or a serial interference canceller is used as the linear detector, the proposed technique achieves about 1.0dB better transmission performance at the BER of 10-5 than the decoder fed with the hard decision signals. In addition, the low computational complexity of the proposed technique is quantitatively evaluated.

  • Spatial-Temporal Aggregated Shuffle Attention for Video Instance Segmentation of Traffic Scene

    Chongren ZHAO  Yinhui ZHANG  Zifen HE  Yunnan DENG  Ying HUANG  Guangchen CHEN  

     
    PAPER-Image Processing and Video Processing

      Pubricized:
    2022/11/24
      Vol:
    E106-D No:2
      Page(s):
    240-251

    Aiming at the problem of spatial focus regions distribution dispersion and dislocation in feature pyramid networks and insufficient feature dependency acquisition in both spatial and channel dimensions, this paper proposes a spatial-temporal aggregated shuffle attention for video instance segmentation (STASA-VIS). First, an mixed subsampling (MS) module to embed activating features from the low-level target area of feature pyramid into the high-level is designed, so as to aggregate spatial information on target area. Taking advantage of the coherent information in video frames, STASA-VIS uses the first ones of every 5 video frames as the key-frames and then propagates the keyframe feature maps of the pyramid layers forward in the time domain, and fuses with the non-keyframe mixed subsampled features to achieve time-domain consistent feature aggregation. Finally, STASA-VIS embeds shuffle attention in the backbone to capture the pixel-level pairwise relationship and dimensional dependencies among the channels and reduce the computation. Experimental results show that the segmentation accuracy of STASA-VIS reaches 41.2%, and the test speed reaches 34FPS, which is better than the state-of-the-art one stage video instance segmentation (VIS) methods in accuracy and achieves real-time segmentation.

  • Influence of Additive and Contaminant Noise on Control-Feedback Induced Chaotic Resonance in Excitatory-Inhibitory Neural Systems

    Sou NOBUKAWA  Nobuhiko WAGATSUMA  Haruhiko NISHIMURA  Keiichiro INAGAKI  Teruya YAMANISHI  

     
    PAPER-Nonlinear Problems

      Pubricized:
    2022/07/07
      Vol:
    E106-A No:1
      Page(s):
    11-22

    Recent developments in engineering applications of stochastic resonance have expanded to various fields, especially biomedicine. Deterministic chaos generates a phenomenon known as chaotic resonance, which is similar to stochastic resonance. However, engineering applications of chaotic resonance are limited owing to the problems in controlling chaos, despite its uniquely high sensitivity to weak signal responses. To tackle these problems, a previous study proposed “reduced region of orbit” (RRO) feedback methods, which cause chaotic resonance using external feedback signals. However, this evaluation was conducted under noise-free conditions. In actual environments, background noise and measurement errors are inevitable in the estimation of RRO feedback strength; therefore, their impact must be elucidated for the application of RRO feedback methods. In this study, we evaluated the chaotic resonance induced by the RRO feedback method in chaotic neural systems in the presence of stochastic noise. Specifically, we focused on the chaotic resonance induced by RRO feedback signals in a neural system composed of excitatory and inhibitory neurons, a typical neural system wherein chaotic resonance is observed in the presence of additive noise and feedback signals including the measurement error (called contaminant noise). It was found that for a relatively small noise strength, both types of noise commonly degenerated the degree of synchronization in chaotic resonance induced by RRO feedback signals, although these characteristics were significantly different. In contrast, chaos-chaos intermittency synchronization was observed for a relatively high noise strength owing to the noise-induced attractor merging bifurcation for both types of noise. In practical neural systems, the influence of noise is unavoidable; therefore, this study highlighted the importance of the countermeasures for noise in the application of chaotic resonance and utilization of noise-induced attractor merging bifurcation.

  • Face Image Generation of Anime Characters Using an Advanced First Order Motion Model with Facial Landmarks

    Junki OSHIBA  Motoi IWATA  Koichi KISE  

     
    PAPER

      Pubricized:
    2022/10/12
      Vol:
    E106-D No:1
      Page(s):
    22-30

    Recently, deep learning for image generation with a guide for the generation has been progressing. Many methods have been proposed to generate the animation of facial expression change from a single face image by transferring some facial expression information to the face image. In particular, the method of using facial landmarks as facial expression information can generate a variety of facial expressions. However, most methods do not focus on anime characters but humans. Moreover, we attempted to apply several existing methods to anime characters by training the methods on an anime character face dataset; however, they generated images with noise, even in regions where there was no change. The first order motion model (FOMM) is an image generation method that takes two images as input and transfers one facial expression or pose to the other. By explicitly calculating the difference between the two images based on optical flow, FOMM can generate images with low noise in the unchanged regions. In the following, we focus on the aspect of the face image generation in FOMM. When we think about the employment of facial landmarks as targets, the performance of FOMM is not enough because FOMM cannot use a facial landmark as a facial expression target because the appearances of a face image and a facial landmark are quite different. Therefore, we propose an advanced FOMM method to use facial landmarks as a facial expression target. In the proposed method, we change the input data and data flow to use facial landmarks. Additionally, to generate face images with expressions that follow the target landmarks more closely, we introduce the landmark estimation loss, which is computed by comparing the landmark detected from the generated image with the target landmark. Our experiments on an anime character face image dataset demonstrated that our method is effective for landmark-guided face image generation for anime characters. Furthermore, our method outperformed other methods quantitatively and generated face images with less noise.

  • Aperture-Shared Multi-Port Waveguide Antenna with Rectangular Dielectric Resonator for 5G Applications

    Purevtseren BAYARSAIKHAN  Ryuji KUSE  Takeshi FUKUSAKO  Kazuma TOMIMOTO  Masayuki MIYASHITA  Ryo YAMAGUCHI  

     
    PAPER-Antennas and Propagation

      Pubricized:
    2022/06/29
      Vol:
    E106-B No:1
      Page(s):
    57-64

    An aperture-shared multi-port waveguide antenna with multiple feeds is presented in this paper. The antenna consists of sequentially rotated four traditional WR-28 waveguides at 28GHz so as to create a multi-polarized function with decoupling between the ports. In addition, a rectangular DR (Dielectric resonator) is mounted at the center of the four apertures to obtain lower mutual coupling over a wide band and to suppress the cross-polarization in the antenna boresight direction. The proposed antenna achieves high gain of 14.4dBi, low mutual coupling of ≤-20dB on average, sufficient cross-polarization discrimination level at ≃20dB in the 27-29GHz frequency band.

  • Projection-Based Physical Adversarial Attack for Monocular Depth Estimation

    Renya DAIMO  Satoshi ONO  

     
    LETTER

      Pubricized:
    2022/10/17
      Vol:
    E106-D No:1
      Page(s):
    31-35

    Monocular depth estimation has improved drastically due to the development of deep neural networks (DNNs). However, recent studies have revealed that DNNs for monocular depth estimation contain vulnerabilities that can lead to misestimation when perturbations are added to input. This study investigates whether DNNs for monocular depth estimation is vulnerable to misestimation when patterned light is projected on an object using a video projector. To this end, this study proposes an evolutionary adversarial attack method with multi-fidelity evaluation scheme that allows creating adversarial examples under black-box condition while suppressing the computational cost. Experiments in both simulated and real scenes showed that the designed light pattern caused a DNN to misestimate objects as if they have moved to the back.

  • EV Aggregation Framework for Spatiotemporal Energy Shifting to Reduce Solar Energy Waste

    Kenshiro KATO  Daichi WATARI  Ittetsu TANIGUCHI  Takao ONOYE  

     
    PAPER-Mathematical Systems Science

      Pubricized:
    2022/09/16
      Vol:
    E106-A No:1
      Page(s):
    54-63

    Solar energy is an important energy resource for a sustainable society and is massively introduced these days. Household generally sells their excess solar energy by the reverse power flow, but the massive reverse power flow usually sacrifices the grid stability. In order to utilize renewable energy effectively and reduce solar energy waste, electric vehicles (EVs) takes an important role to fill in the spatiotemporal gap of solar energy. This paper proposes a novel EV aggregation framework for spatiotemporal shifting of solar energy without any reverse power flow. The proposed framework causes charging and discharging via an EV aggregator by intentionally changing the price, and the solar energy waste is expected to reduce by the energy trade. Simulation results show the proposed framework reduced the solar energy waste by 68%.

  • Face Hallucination via Multi-Scale Structure Prior Learning

    Yuexi YAO  Tao LU  Kanghui ZHAO  Yanduo ZHANG  Yu WANG  

     
    LETTER-Image

      Pubricized:
    2022/07/19
      Vol:
    E106-A No:1
      Page(s):
    92-96

    Recently, the face hallucination method based on deep learning understands the mapping between low-resolution (LR) and high-resolution (HR) facial patterns by exploring the priors of facial structure. However, how to maintain the face structure consistency after the reconstruction of face images at different scales is still a challenging problem. In this letter, we propose a novel multi-scale structure prior learning (MSPL) for face hallucination. First, we propose a multi-scale structure prior block (MSPB). Considering the loss of high-frequency information in the LR space, we mainly process the input image in three different scale ascending dimensional spaces, and map the image to the high dimensional space to extract multi-scale structural prior information. Then the size of feature maps is recovered by downsampling, and finally the multi-scale information is fused to restore the feature channels. On this basis, we propose a local detail attention module (LDAM) to focus on the local texture information of faces. We conduct extensive face hallucination reconstruction experiments on a public face dataset (LFW) to verify the effectiveness of our method.

  • CAA-Net: End-to-End Two-Branch Feature Attention Network for Single Image Dehazing

    Gang JIN  Jingsheng ZHAI  Jianguo WEI  

     
    PAPER-Digital Signal Processing

      Pubricized:
    2022/07/21
      Vol:
    E106-A No:1
      Page(s):
    1-10

    In this paper, we propose an end-to-end two-branch feature attention network. The network is mainly used for single image dehazing. The network consists of two branches, we call it CAA-Net: 1) A U-NET network composed of different-level feature fusion based on attention (FEPA) structure and residual dense block (RDB). In order to make full use of all the hierarchical features of the image, we use RDB. RDB contains dense connected layers and local feature fusion with local residual learning. We also propose a structure which called FEPA.FEPA structure could retain the information of shallow layer and transfer it to the deep layer. FEPA is composed of serveral feature attention modules (FPA). FPA combines local residual learning with channel attention mechanism and pixel attention mechanism, and could extract features from different channels and image pixels. 2) A network composed of several different levels of FEPA structures. The network could make feature weights learn from FPA adaptively, and give more weight to important features. The final output result of CAA-Net is the combination of all branch prediction results. Experimental results show that the CAA-Net proposed by us surpasses the most advanced algorithms before for single image dehazing.

  • Metacognitive Adaptation to Enhance Lifelong Language Learning

    Han WANG  Ruiliu FU  Xuejun ZHANG  Jun ZHOU  Qingwei ZHAO  

     
    LETTER-Natural Language Processing

      Pubricized:
    2022/10/06
      Vol:
    E106-D No:1
      Page(s):
    86-90

    Lifelong language learning (LLL) aims at learning new tasks and retaining old tasks in the field of NLP. LAMOL is a recent LLL framework following data-free constraints. Previous works have been researched based on LAMOL with additional computing with more time costs or new parameters. However, they still have a gap between multi-task learning (MTL), which is regarded as the upper bound of LLL. In this paper, we propose Metacognitive Adaptation (Metac-Adapt) almost without adding additional time cost and computational resources to make the model generate better pseudo samples and then replay them. Experimental results demonstrate that Metac-Adapt is on par with MTL or better.

  • A Non-Intrusive Speech Quality Evaluation Method Based on the Audiogram and Weighted Frequency Information for Hearing Aid

    Ruxue GUO  Pengxu JIANG  Ruiyu LIANG  Yue XIE  Cairong ZOU  

     
    LETTER-Speech and Hearing

      Pubricized:
    2022/07/25
      Vol:
    E106-A No:1
      Page(s):
    64-68

    For a long time, the compensation effect of hearing aid is mainly evaluated subjectively, and there are fewer studies of objective evaluation. Furthermore, a pure speech signal is generally required as a reference in the existing objective evaluation methods, which restricts the practicality in a real-world environment. Therefore, this paper presents a non-intrusive speech quality evaluation method for hearing aid, which combines the audiogram and weighted frequency information. The proposed model mainly includes an audiogram information extraction network, a frequency information extraction network, and a quality score mapping network. The audiogram is the input of the audiogram information extraction network, which helps the system capture the information related to hearing loss. In addition, the low-frequency bands of speech contain loudness information and the medium and high-frequency components contribute to semantic comprehension. The information of two frequency bands is input to the frequency information extraction network to obtain time-frequency information. When obtaining the high-level features of different frequency bands and audiograms, they are fused into two groups of tensors that distinguish the information of different frequency bands and used as the input of the attention layer to calculate the corresponding weight distribution. Finally, a dense layer is employed to predict the score of speech quality. The experimental results show that it is reasonable to combine the audiogram and the weight of the information from two frequency bands, which can effectively realize the evaluation of the speech quality of the hearing aid.

  • Image and Model Transformation with Secret Key for Vision Transformer

    Hitoshi KIYA  Ryota IIJIMA  Aprilpyone MAUNGMAUNG  Yuma KINOSHITA  

     
    INVITED PAPER

      Pubricized:
    2022/11/02
      Vol:
    E106-D No:1
      Page(s):
    2-11

    In this paper, we propose a combined use of transformed images and vision transformer (ViT) models transformed with a secret key. We show for the first time that models trained with plain images can be directly transformed to models trained with encrypted images on the basis of the ViT architecture, and the performance of the transformed models is the same as models trained with plain images when using test images encrypted with the key. In addition, the proposed scheme does not require any specially prepared data for training models or network modification, so it also allows us to easily update the secret key. In an experiment, the effectiveness of the proposed scheme is evaluated in terms of performance degradation and model protection performance in an image classification task on the CIFAR-10 dataset.

  • Learning Sparse Graph with Minimax Concave Penalty under Gaussian Markov Random Fields

    Tatsuya KOYAKUMARU  Masahiro YUKAWA  Eduardo PAVEZ  Antonio ORTEGA  

     
    PAPER-Graphs and Networks

      Pubricized:
    2022/07/01
      Vol:
    E106-A No:1
      Page(s):
    23-34

    This paper presents a convex-analytic framework to learn sparse graphs from data. While our problem formulation is inspired by an extension of the graphical lasso using the so-called combinatorial graph Laplacian framework, a key difference is the use of a nonconvex alternative to the l1 norm to attain graphs with better interpretability. Specifically, we use the weakly-convex minimax concave penalty (the difference between the l1 norm and the Huber function) which is known to yield sparse solutions with lower estimation bias than l1 for regression problems. In our framework, the graph Laplacian is replaced in the optimization by a linear transform of the vector corresponding to its upper triangular part. Via a reformulation relying on Moreau's decomposition, we show that overall convexity is guaranteed by introducing a quadratic function to our cost function. The problem can be solved efficiently by the primal-dual splitting method, of which the admissible conditions for provable convergence are presented. Numerical examples show that the proposed method significantly outperforms the existing graph learning methods with reasonable computation time.

  • Construction of Odd-Variable Strictly Almost Optimal Resilient Boolean Functions with Higher Resiliency Order via Modifying High-Meets-Low Technique

    Hui GE  Zepeng ZHUO  Xiaoni DU  

     
    LETTER-Cryptography and Information Security

      Pubricized:
    2022/07/12
      Vol:
    E106-A No:1
      Page(s):
    73-77

    Construction of resilient Boolean functions in odd variables having strictly almost optimal (SAO) nonlinearity appears to be a rather difficult task in stream cipher and coding theory. In this paper, based on the modified High-Meets-Low technique, a general construction to obtain odd-variable SAO resilient Boolean functions without directly using PW functions or KY functions is presented. It is shown that the new class of functions possess higher resiliency order than the known functions while keeping higher SAO nonlinearity, and in addition the resiliency order increases rapidly with the variable number n.

821-840hit(26286hit)