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1541-1560hit(42807hit)

  • Gray Augmentation Exploration with All-Modality Center-Triplet Loss for Visible-Infrared Person Re-Identification

    Xiaozhou CHENG  Rui LI  Yanjing SUN  Yu ZHOU  Kaiwen DONG  

     
    LETTER-Image Recognition, Computer Vision

      Pubricized:
    2022/04/06
      Vol:
    E105-D No:7
      Page(s):
    1356-1360

    Visible-Infrared Person Re-identification (VI-ReID) is a challenging pedestrian retrieval task due to the huge modality discrepancy and appearance discrepancy. To address this tough task, this letter proposes a novel gray augmentation exploration (GAE) method to increase the diversity of training data and seek the best ratio of gray augmentation for learning a more focused model. Additionally, we also propose a strong all-modality center-triplet (AMCT) loss to push the features extracted from the same pedestrian more compact but those from different persons more separate. Experiments conducted on the public dataset SYSU-MM01 demonstrate the superiority of the proposed method in the VI-ReID task.

  • Measurement of Complex Waveforms in Wide Wavelength Range by Using Wavelength-Swept Light Source and Linear Optical Sampling

    Sougo SHIMIZU  Chao ZHANG  Fumihiko ITO  

     
    PAPER-Fiber-Optic Transmission for Communications

      Pubricized:
    2021/12/28
      Vol:
    E105-B No:7
      Page(s):
    797-804

    This paper describes a method to evaluate the modulated waveforms output by a high-speed external phase modulator over a wide wavelength range by using linear optical sampling (LOS) and a wavelength-swept light source. The phase-modulated waveform is sampled by LOS together with the reference signal before modulation, and the modulation waveform is observed by removing the phase noise of the light source extracted from the reference signal. In this process, the frequency offset caused by the optical-path length difference between the measurement and reference interferometers is removed by digital signal processing. A pseudo-random binary-sequence modulated signal is observed with a temporal resolution of 10ps. We obtained a dynamic range of ∼40dB for the measurement bandwidth of 10 nm. When the measurement bandwidth is expanded to entire C-Band (∼35nm), the dynamic ranges of 37∼46dB were observed, depending on the wavelengths. The measurement time was sub-seconds throughout the experiment.

  • Weighted Gradient Pretrain for Low-Resource Speech Emotion Recognition

    Yue XIE  Ruiyu LIANG  Xiaoyan ZHAO  Zhenlin LIANG  Jing DU  

     
    LETTER-Speech and Hearing

      Pubricized:
    2022/04/04
      Vol:
    E105-D No:7
      Page(s):
    1352-1355

    To alleviate the problem of the dependency on the quantity of the training sample data in speech emotion recognition, a weighted gradient pre-train algorithm for low-resource speech emotion recognition is proposed. Multiple public emotion corpora are used for pre-training to generate shared hidden layer (SHL) parameters with the generalization ability. The parameters are used to initialize the downsteam network of the recognition task for the low-resource dataset, thereby improving the recognition performance on low-resource emotion corpora. However, the emotion categories are different among the public corpora, and the number of samples varies greatly, which will increase the difficulty of joint training on multiple emotion datasets. To this end, a weighted gradient (WG) algorithm is proposed to enable the shared layer to learn the generalized representation of different datasets without affecting the priority of the emotion recognition on each corpus. Experiments show that the accuracy is improved by using CASIA, IEMOCAP, and eNTERFACE as the known datasets to pre-train the emotion models of GEMEP, and the performance could be improved further by combining WG with gradient reversal layer.

  • A Multi-Layer SIW Resonator Loaded with Asymmetric E-Shaped Slot-Lines for a Miniaturized Tri-Band BPF with Low Radiation Loss

    Weiyu ZHOU  Satoshi ONO  Koji WADA  

     
    PAPER-Microwaves, Millimeter-Waves

      Pubricized:
    2021/12/27
      Vol:
    E105-C No:7
      Page(s):
    349-357

    This paper proposes a novel multi-layer substrate integrated waveguide (SIW) resonator loaded with asymmetric E-shaped slot-lines and shows a tri-band band-pass filter (BPF) using the proposed structure. In the previous literature, various SIW resonators have been proposed to simultaneously solve the problems of large area and high insertion loss. Although these SIWs have a lower insertion loss than planar-type resonators using a printed circuit board, the size of these structures tends to be larger. A multi-layer SIW resonator loaded with asymmetric E-shaped slot-lines can solve the above problems and realize a tri-band BPF without increasing the size to realize further miniaturization. The theoretical design method and the structural design are shown. Moreover, the configured structure is fabricated and measured for showing the validity of the design method in this paper.

  • A Large-Scale SCMA Codebook Optimization and Codeword Allocation Method

    Shiqing QIAN  Wenping GE  Yongxing ZHANG  Pengju ZHANG  

     
    PAPER-Fundamental Theories for Communications

      Pubricized:
    2021/12/24
      Vol:
    E105-B No:7
      Page(s):
    788-796

    Sparse code division multiple access (SCMA) is a non-orthogonal multiple access (NOMA) technology that can improve frequency band utilization and allow many users to share quite a few resource elements (REs). This paper uses the modulation of lattice theory to develop a systematic construction procedure for the design of SCMA codebooks under Gaussian channel environments that can achieve near-optimal designs, especially for cases that consider large-scale SCMA parameters. However, under the condition of large-scale SCMA parameters, the mother constellation (MC) points will overlap, which can be solved by the method of the partial dimensions transformation (PDT). More importantly, we consider the upper bounded error probability of the signal transmission in the AWGN channels, and design a codeword allocation method to reduce the inter symbol interference (ISI) on the same RE. Simulation results show that under different codebook sizes and different overload rates, using two different message passing algorithms (MPA) to verify, the codebook proposed in this paper has a bit error rate (BER) significantly better than the reference codebooks, moreover the convergence time does not exceed that of the reference codebooks.

  • A Large-Scale Bitcoin Abuse Measurement and Clustering Analysis Utilizing Public Reports

    Jinho CHOI  Jaehan KIM  Minkyoo SONG  Hanna KIM  Nahyeon PARK  Minjae SEO  Youngjin JIN  Seungwon SHIN  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2022/04/07
      Vol:
    E105-D No:7
      Page(s):
    1296-1307

    Cryptocurrency abuse has become a critical problem. Due to the anonymous nature of cryptocurrency, criminals commonly adopt cryptocurrency for trading drugs and deceiving people without revealing their identities. Despite its significance and severity, only few works have studied how cryptocurrency has been abused in the real world, and they only provide some limited measurement results. Thus, to provide a more in-depth understanding on the cryptocurrency abuse cases, we present a large-scale analysis on various Bitcoin abuse types using 200,507 real-world reports collected by victims from 214 countries. We scrutinize observable abuse trends, which are closely related to real-world incidents, to understand the causality of the abuses. Furthermore, we investigate the semantics of various cryptocurrency abuse types to show that several abuse types overlap in meaning and to provide valuable insight into the public dataset. In addition, we delve into abuse channels to identify which widely-known platforms can be maliciously deployed by abusers following the COVID-19 pandemic outbreak. Consequently, we demonstrate the polarization property of Bitcoin addresses practically utilized on transactions, and confirm the possible usage of public report data for providing clues to track cyber threats. We expect that this research on Bitcoin abuse can empirically reach victims more effectively than cybercrime, which is subject to professional investigation.

  • A Survey on Explainable Fake News Detection

    Ken MISHIMA  Hayato YAMANA  

     
    SURVEY PAPER-Data Engineering, Web Information Systems

      Pubricized:
    2022/04/22
      Vol:
    E105-D No:7
      Page(s):
    1249-1257

    The increasing amount of fake news is a growing problem that will progressively worsen in our interconnected world. Machine learning, particularly deep learning, is being used to detect misinformation; however, the models employed are essentially black boxes, and thus are uninterpretable. This paper presents an overview of explainable fake news detection models. Specifically, we first review the existing models, datasets, evaluation techniques, and visualization processes. Subsequently, possible improvements in this field are identified and discussed.

  • Event-Triggered Global Regulation of an Uncertain Chain of Integrators under Unknown Time-Varying Input Delay

    Sang-Young OH  Ho-Lim CHOI  

     
    LETTER-Systems and Control

      Pubricized:
    2021/12/24
      Vol:
    E105-A No:7
      Page(s):
    1091-1095

    We consider a regulation problem for an uncertain chain of integrators with an unknown time-varying delay in the input. To deal with uncertain parameters and unknown delay, we propose an adaptive event-triggered controller with a dynamic gain. We show that the system is globally regulated and interexecution times are lower bounded. Moreover, we show that these lower bounds can be enlarged by adjusting a control parameter. An example is given for clear illustration.

  • A Satellite Handover Strategy Based on Heuristic Algorithm for LEO Satellite Networks

    Senbai ZHANG  Aijun LIU  Chen HAN  Xiaohu LIANG  Xiang DING  Aihong LU  

     
    PAPER-Satellite Communications

      Pubricized:
    2022/01/13
      Vol:
    E105-B No:7
      Page(s):
    876-884

    Due to the significant difference in speed between the user terminals (UTs) and the low earth orbit (LEO) satellites, it is necessary to solve the frequent handover of UTs at the edge of the moving satellite beams. Besides, as the development of LEO satellite communications, the scale of constellations and the number of UTs undergoing massive increase. Thus, in this paper, a satellite handover strategy is proposed to improve the handover performances of UTs and satellites. We define the utility function of handover jointly by considering the quality of experience of UTs, the throughput of satellites and the load balancing of network. Then, a coding method is proposed to represent the combinations of UTs and satellites. To reduce the calculational cost, an access and handover strategy based on a heuristic algorithm is proposed to search the optimal handover result. Finally, simulations show the effectiveness and superiority of the proposed strategy.

  • A Solar-Cell-Assisted, 99% Biofuel Cell Area Reduced, Biofuel-Cell-Powered Wireless Biosensing System in 65nm CMOS for Continuous Glucose Monitoring Contact Lenses Open Access

    Guowei CHEN  Kiichi NIITSU  

     
    BRIEF PAPER

      Pubricized:
    2022/01/05
      Vol:
    E105-C No:7
      Page(s):
    343-348

    This brief proposes a solar-cell-assisted wireless biosensing system that operates using a biofuel cell (BFC). To facilitate BFC area reduction for the use of this system in area-constrained continuous glucose monitoring contact lenses, an energy harvester combined with an on-chip solar cell is introduced as a dedicated power source for the transmitter. A dual-oscillator-based supply voltage monitor is employed to convert the BFC output into digital codes. From measurements of the test chip fabricated in 65-nm CMOS technology, the proposed system can achieve 99% BFC area reduction.

  • MFG-Based Decentralized Charging Control Design of Large-Scale PEVs with Consideration of Collective Consensus

    Qiaobin FU  Zhenhui XU  Kenichi TAKAI  Tielong SHEN  

     
    PAPER-Systems and Control

      Pubricized:
    2022/01/18
      Vol:
    E105-A No:7
      Page(s):
    1038-1048

    This paper investigates the charging control strategy design problem of a large-scale plug-in electric vehicle (PEV) group, where each PEV aims to find an optimal charging strategy to minimize its own cost function. It should be noted that the collective behavior of the group is coupled in the individual cost function, which complicates the design of decentralized charging strategies. To obtain the decentralized charging strategy, a mean-field game (MFG) formulation is proposed where a penalty on collective consensus is embedded and a class of mean-field coupled time-varying stochastic systems is targeted for solving the MFG which involves the charging model of PEVs as a special case. Then, an augmented system with dimension extension and the policy iteration algorithm are proposed to solve the mean-field game problem for the class of mean-field coupled time-varying stochastic systems. Moreover, analysis of the convergence of proposed approach has been studied. Last, simulation is conducted to illustrate the effectiveness of the proposed MFG-based charging control strategy and shows that the charging control strategy can achieve desired mean-field state and impact to the power grid can be buffered.

  • FOREWORD Open Access

    Masafumi TAKAHASHI  

     
    FOREWORD

      Vol:
    E105-C No:7
      Page(s):
    300-300
  • Loan Default Prediction with Deep Learning and Muddling Label Regularization

    Weiwei JIANG  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2022/04/04
      Vol:
    E105-D No:7
      Page(s):
    1340-1342

    Loan default prediction has been a significant problem in the financial domain because overdue loans may incur significant losses. Machine learning methods have been introduced to solve this problem, but there are still many challenges including feature multicollinearity, imbalanced labels, and small data sample problems. To replicate the success of deep learning in many areas, an effective regularization technique named muddling label regularization is introduced in this letter, and an ensemble of feed-forward neural networks is proposed, which outperforms machine learning and deep learning baselines in a real-world dataset.

  • Position Estimation for the Capsule Endoscope Using High-Definition Numerical Human Body Model and Measurement Open Access

    Akihiro YOSHITAKE  Masaharu TAKAHASHI  

     
    PAPER-Antennas and Propagation

      Pubricized:
    2022/01/11
      Vol:
    E105-B No:7
      Page(s):
    848-855

    Currently, wireless power transmission technology is being developed for capsule endoscopes. By removing the battery, the capsule endoscope is miniaturized, the number of images that can be taken increases, and the risk of harmful substances leaking from the battery when it is damaged inside the body is avoided. Furthermore, diagnostic accuracy is improved by adjusting the directivity of radio waves according to the position of the capsule endoscope to improve efficiency and adjusting the number of images to be taken according to position by real-time position estimation. In this study, we report the result of position estimation in a high-definition numerical human body model and in an experiment on an electromagnetic phantom.

  • Time-Based Current Source: A Highly Digital Robust Current Generator for Switched Capacitor Circuits

    Kentaro YOSHIOKA  

     
    PAPER

      Pubricized:
    2022/01/05
      Vol:
    E105-C No:7
      Page(s):
    324-333

    The resistor variation can severely affect current reference sources, which may vary up to ±40% in scaled CMOS processes. In addition, such variations make the opamp design challenging and increase the design margin, impacting power consumption. This paper proposes a Time-Based Current Source (TBCS): a robust and process-scalable reference current source suitable for switched-capacitor (SC) circuits. We construct a delay-locked-loop (DLL) to lock the current-starved inverter with the reference clock, enabling the use of the settled current directly as a reference current. Since the load capacitors determine the delay, the generated current is decoupled from resistor values and enables a robust reference current source. The prototype TBCS fabricated in 28nm CMOS achieved a minimal area of 1200um2. The current variation is suppressed to half compared to BGR based current sources, confirmed in extensive PVT variation simulations. Moreover, when used as the opamp's bias, TBCS achieves comparable opamp GBW to an ideal current source.

  • IEEE754 Binary32 Floating-Point Logarithmic Algorithms Based on Taylor-Series Expansion with Mantissa Region Conversion and Division

    Jianglin WEI  Anna KUWANA  Haruo KOBAYASHI  Kazuyoshi KUBO  

     
    PAPER-Digital Signal Processing

      Pubricized:
    2022/01/17
      Vol:
    E105-A No:7
      Page(s):
    1020-1027

    In this paper, an algorithm based on Taylor series expansion is proposed to calculate the logarithm (log2x) of IEEE754 binary32 accuracy floating-point number by a multi-domain partitioning method. The general mantissa (1≤x<2) is multiplied by 2, 4, 8, … (or equivalently left-shifted by 1, 2, 3, … bits), the regions of (2≤x<4), (4≤x<8), (8≤x<16),… are considered, and Taylor-series expansion is applied. In those regions, the slope of f(x)=log2 x with respect to x is gentle compared to the region of (1≤x<2), which reduces the required number of terms. We also consider the trade-offs among the numbers of additions, subtractions, and multiplications and Look-Up Table (LUT) size in hardware to select the best algorithm for the engineer's design and build the best hardware device.

  • Design Verification Methodology of Pipelined RISC-V Processor Using C2RTL Framework

    Eiji YOSHIYA  Tomoya NAKANISHI  Tsuyoshi ISSHIKI  

     
    PAPER-VLSI Design Technology and CAD

      Pubricized:
    2021/12/23
      Vol:
    E105-A No:7
      Page(s):
    1061-1069

    In Internet of Things (IoT) applications, system-on-chip (SoCs) with embedded processors are widely used. As an embedded processor, RISC-V, which is license-free and has an extensible instruction set, is receiving attention. However, designing such embedded processors requires an enormous effort to achieve a highly efficient microarchitecture in terms of performance, power consumption, and circuit area, as well as the design verification of running complex software, including modern operating systems such as Linux. In this paper, we propose a method for directly describing the RTL structure of a pipelined RISC-V processor with cache memories, a memory management unit (MMU), and an AXI bus interface using the C++ language. This pipelined processor C++ model serves as a functional simulator of the complete RISC-V core, whereas our C2RTL framework translates the processor C++ model into a cycle-accurate RTL description in the Verilog-HDL and RTL-equivalent C model. Our processor design methodology using the C2RTL framework is unique compared to other existing methodologies because both the simulation and RTL models are derived from the same C++ source, which greatly simplifies the design verification and optimization processes. The effectiveness of our design methodology is demonstrated on a RISC-V processor that runs Linux OS on an FPGA board, achieving a significantly short simulation time of the original C++ processor model and RTL-equivalent C model in comparison to a commercial RTL simulator.

  • Hardware-Trojan Detection Based on the Structural Features of Trojan Circuits Using Random Forests

    Tatsuki KURIHARA  Nozomu TOGAWA  

     
    PAPER-VLSI Design Technology and CAD

      Pubricized:
    2022/01/07
      Vol:
    E105-A No:7
      Page(s):
    1049-1060

    Recently, with the spread of Internet of Things (IoT) devices, embedded hardware devices have been used in a variety of everyday electrical items. Due to the increased demand for embedded hardware devices, some of the IC design and manufacturing steps have been outsourced to third-party vendors. Since malicious third-party vendors may insert malicious circuits, called hardware Trojans, into their products, developing an effective hardware-Trojan detection method is strongly required. In this paper, we propose 25 hardware-Trojan features focusing on the structure of trigger circuits for machine-learning-based hardware-Trojan detection. Combining the proposed features into 11 existing hardware-Trojan features, we totally utilize 36 hardware-Trojan features for classification. Then we classify the nets in an unknown netlist into a set of normal nets and Trojan nets based on a random-forest classifier. The experimental results demonstrate that the average true positive rate (TPR) becomes 64.2% and the average true negative rate (TNR) becomes 100.0%. They improve the average TPR by 14.8 points while keeping the average TNR compared to existing state-of-the-art methods. In particular, the proposed method successfully finds out Trojan nets in several benchmark circuits, which are not found by the existing method.

  • A Lower Bound on the Maximum Correlation Magnitude Outside LHZ for LHZ-FHS Sets

    Xiaoxiao CUI  Cuiling FAN  Xiaoni DU  

     
    LETTER-Coding Theory

      Pubricized:
    2022/01/21
      Vol:
    E105-A No:7
      Page(s):
    1096-1100

    Low-hit-zone frequency-hopping sequences (LHZ-FHSs) are frequency-hopping sequences with low Hamming correlation in a low-hit-zone (LHZ), which have important applications in quasi-synchronous communication systems. However, the strict quasi-synchronization may be hard to maintain at all times in practical FHMA networks, it is also necessary to minimize the Hamming correlation for time-shifts outside of the LHZ. The main objective of this letter is to propose a lower bound on the maximum correlation magnitude outside the low-hit-zone for LHZ-FHS sets. It turns out that the proposed bound is tight or almost tight in the sense that it can be achieved by some LHZ-FHS sets.

  • A Two-Level Cache Aware Adaptive Data Replication Mechanism for Shared LLC

    Qianqian WU  Zhenzhou JI  

     
    LETTER-Computer System

      Pubricized:
    2022/03/25
      Vol:
    E105-D No:7
      Page(s):
    1320-1324

    The shared last level cache (SLLC) in tile chip multiprocessors (TCMP) provides a low off-chip miss rate, but it causes a long on-chip access latency. In the two-level cache hierarchy, data replication stores replicas of L1 victims in the local LLC (L2 cache) to obtain a short local LLC access latency on the next accesses. Many data replication mechanisms have been proposed, but they do not consider both L1 victim reuse behaviors and LLC replica reception capability. They either produce many useless replicas or increase LLC pressure, which limits the improvement of system performance. In this paper, we propose a two-level cache aware adaptive data replication mechanism (TCDR), which controls replication based on both L1 victim reuse behaviors prediction and LLC replica reception capability monitoring. TCDR not only increases the accuracy of L1 replica selection, but also avoids the pressure of replication on LLC. The results show that TCDR improves the system performance with reasonable hardware overhead.

1541-1560hit(42807hit)