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

Keyword Search Result

[Keyword] CTI(8214hit)

401-420hit(8214hit)

  • Exploring Hypotactic Structure for Chinese-English Machine Translation with a Structure-Aware Encoder-Decoder Neural Model

    Guoyi MIAO  Yufeng CHEN  Mingtong LIU  Jinan XU  Yujie ZHANG  Wenhe FENG  

     
    PAPER-Natural Language Processing

      Pubricized:
    2022/01/11
      Vol:
    E105-D No:4
      Page(s):
    797-806

    Translation of long and complex sentence has always been a challenge for machine translation. In recent years, neural machine translation (NMT) has achieved substantial progress in modeling the semantic connection between words in a sentence, but it is still insufficient in capturing discourse structure information between clauses within complex sentences, which often leads to poor discourse coherence when translating long and complex sentences. On the other hand, the hypotactic structure, a main component of the discourse structure, plays an important role in the coherence of discourse translation, but it is not specifically studied. To tackle this problem, we propose a novel Chinese-English NMT approach that incorporates the hypotactic structure knowledge of complex sentences. Specifically, we first annotate and build a hypotactic structure aligned parallel corpus to provide explicit hypotactic structure knowledge of complex sentences for NMT. Then we propose three hypotactic structure-aware NMT models with three different fusion strategies, including source-side fusion, target-side fusion, and both-side fusion, to integrate the annotated structure knowledge into NMT. Experimental results on WMT17, WMT18 and WMT19 Chinese-English translation tasks demonstrate that the proposed method can significantly improve the translation performance and enhance the discourse coherence of machine translation.

  • Master-Teacher-Student: A Weakly Labelled Semi-Supervised Framework for Audio Tagging and Sound Event Detection

    Yuzhuo LIU  Hangting CHEN  Qingwei ZHAO  Pengyuan ZHANG  

     
    LETTER-Speech and Hearing

      Pubricized:
    2022/01/13
      Vol:
    E105-D No:4
      Page(s):
    828-831

    Weakly labelled semi-supervised audio tagging (AT) and sound event detection (SED) have become significant in real-world applications. A popular method is teacher-student learning, making student models learn from pseudo-labels generated by teacher models from unlabelled data. To generate high-quality pseudo-labels, we propose a master-teacher-student framework trained with a dual-lead policy. Our experiments illustrate that our model outperforms the state-of-the-art model on both tasks.

  • Interleaved Sequences with Anti-Doppler Properties

    Xi CAO  Yang YANG  Rong LUO  

     
    LETTER-Coding Theory

      Pubricized:
    2021/10/05
      Vol:
    E105-A No:4
      Page(s):
    734-738

    In this letter, we discuss the ambiguity function of interleaved sequences. Furthermore, using the Guassian sum and choosing binary m-sequences as column sequences, we investigate the property of a binary sequence set given by Zhou, Tang, Gong (IEEE Trans. Inf. Theory, 54(9), 2008), which has low ambiguity property in a large region. Those sequences could be used in radar systems.

  • Cylindrical Massive MIMO System with Low-Complexity Angle-Based User Selection for High-Altitude Platform Stations

    Koji TASHIRO  Kenji HOSHINO  Atsushi NAGATE  

     
    PAPER-Adaptive Array Antennas/MIMO

      Pubricized:
    2021/10/15
      Vol:
    E105-B No:4
      Page(s):
    449-460

    High-altitude platform stations (HAPSs) are recognized as a promising technology for coverage extension in the sixth generation (6G) mobile communications and beyond. The purpose of this study is to develop a HAPS system with a coverage radius of 100km and high capacity by focusing on the following two aspects: array antenna structure and user selection. HAPS systems must jointly use massive multiple-input multiple-output (mMIMO) and multiuser MIMO techniques to increase their capacity. However, the coverage achieved by a conventional planar array antenna is limited to a circular area with a radius of only tens of kilometers. A conventional semi-orthogonal user selection (SUS) scheme based on the orthogonality of channel vectors achieves high capacity, but it has high complexity. First, this paper proposes a cylindrical mMIMO system to achieve an ultra-wide coverage radius of 100km and high capacity. Second, this paper presents a novel angle-based user selection (AUS) scheme, where a user selection problem is formulated as a maximization of the minimum angular difference between users over all user groups. Finally, a low-complexity suboptimal algorithm (SA) for AUS is also proposed. Assuming an area with a 100km radius, simulation results demonstrate that the proposed cylindrical mMIMO system improves the signal-to-interference-plus-noise ratio by approx. 12dB at the boundary of the area, and it achieves approx. 1.5 times higher capacity than the conventional mMIMO which uses a planar array antenna. In addition, the results show that the proposed AUS scheme improves the lower percentiles in the system capacity distribution compared with SUS and basic random user selection. Furthermore, the computational complexity of the proposed SA is in the order of only 1/4000 that of SUS.

  • SIBYL: A Method for Detecting Similar Binary Functions Using Machine Learning

    Yuma MASUBUCHI  Masaki HASHIMOTO  Akira OTSUKA  

     
    PAPER-Dependable Computing

      Pubricized:
    2021/12/28
      Vol:
    E105-D No:4
      Page(s):
    755-765

    Binary code similarity comparison methods are mainly used to find bugs in software, to detect software plagiarism, and to reduce the workload during malware analysis. In this paper, we propose a method to compare the binary code similarity of each function by using a combination of Control Flow Graphs (CFGs) and disassembled instruction sequences contained in each function, and to detect a function with high similarity to a specified function. One of the challenges in performing similarity comparisons is that different compile-time optimizations and different architectures produce different binary code. The main units for comparing code are instructions, basic blocks and functions. The challenge of functions is that they have a graph structure in which basic blocks are combined, making it relatively difficult to derive similarity. However, analysis tools such as IDA, display the disassembled instruction sequence in function units. Detecting similarity on a function basis has the advantage of facilitating simplified understanding by analysts. To solve the aforementioned challenges, we use machine learning methods in the field of natural language processing. In this field, there is a Transformer model, as of 2017, that updates each record for various language processing tasks, and as of 2021, Transformer is the basis for BERT, which updates each record for language processing tasks. There is also a method called node2vec, which uses machine learning techniques to capture the features of each node from the graph structure. In this paper, we propose SIBYL, a combination of Transformer and node2vec. In SIBYL, a method called Triplet-Loss is used during learning so that similar items are brought closer and dissimilar items are moved away. To evaluate SIBYL, we created a new dataset using open-source software widely used in the real world, and conducted training and evaluation experiments using the dataset. In the evaluation experiments, we evaluated the similarity of binary codes across different architectures using evaluation indices such as Rank1 and MRR. The experimental results showed that SIBYL outperforms existing research. We believe that this is due to the fact that machine learning has been able to capture the features of the graph structure and the order of instructions on a function-by-function basis. The results of these experiments are presented in detail, followed by a discussion and conclusion.

  • Experiment of Integrated Technologies in Robotics, Network, and Computing for Smart Agriculture Open Access

    Ryota ISHIBASHI  Takuma TSUBAKI  Shingo OKADA  Hiroshi YAMAMOTO  Takeshi KUWAHARA  Kenichi KAWAMURA  Keisuke WAKAO  Takatsune MORIYAMA  Ricardo OSPINA  Hiroshi OKAMOTO  Noboru NOGUCHI  

     
    INVITED PAPER

      Pubricized:
    2021/11/05
      Vol:
    E105-B No:4
      Page(s):
    364-378

    To sustain and expand the agricultural economy even as its workforce shrinks, the efficiency of farm operations must be improved. One key to efficiency improvement is completely unmanned driving of farm machines, which requires stable monitoring and control of machines from remote sites, a safety system to ensure safe autonomous driving even without manual operations, and precise positioning in not only small farm fields but also wider areas. As possible solutions for those issues, we have developed technologies of wireless network quality prediction, an end-to-end overlay network, machine vision for safety and positioning, network cooperated vehicle control and autonomous tractor control and conducted experiments in actual field environments. Experimental results show that: 1) remote monitoring and control can be seamlessly continued even when connection between the tractor and the remote site needs to be switched across different wireless networks during autonomous driving; 2) the safety of the autonomous driving can automatically be ensured by detecting both the existence of people in front of the unmanned tractor and disturbance of network quality affecting remote monitoring operation; and 3) the unmanned tractor can continue precise autonomous driving even when precise positioning by satellite systems cannot be performed.

  • Construction of Two Classes of Minimal Binary Linear Codes Based on Boolean Function

    Jiawei DU  Xiaoni DU  Wengang JIN  Yingzhong ZHANG  

     
    PAPER-Cryptography and Information Security

      Pubricized:
    2021/09/30
      Vol:
    E105-A No:4
      Page(s):
    689-693

    Linear codes with a few-weight have important applications in combinatorial design, strongly regular graphs and cryptography. In this paper, we first construct a class of Boolean functions with at most five-valued Walsh spectra, and determine their spectrum distribution. Then, we derive two classes of linear codes with at most six-weight from the new functions. Meanwhile, the length, dimension and weight distributions of the codes are obtained. Results show that both of the new codes are minimal and among them, one is wide minimal code and the other is a narrow minimal code and thus can be used to design secret sharing scheme with good access structures. Finally, some Magma programs are used to verify the correctness of our results.

  • Dynamic Service Chain Construction Based on Model Predictive Control in NFV Environments

    Masaya KUMAZAKI  Masaki OGURA  Takuji TACHIBANA  

     
    PAPER-Network Virtualization

      Pubricized:
    2021/10/15
      Vol:
    E105-B No:4
      Page(s):
    399-410

    For beyond 5G era, in network function virtualization (NFV) environments, service chaining can be utilized to provide the flexible network infrastructures needed to support the creation of various application services. In this paper, we propose a dynamic service chain construction based on model predictive control (MPC) to utilize network resources. In the proposed method, the number of data packets in the buffer at each node is modeled as a dynamical system for MPC. Then, we formulate an optimization problem with the predicted amount of traffic injecting into each service chain from users for the dynamical system. In the optimization problem, the transmission route of each service chain, the node where each VNF is placed, and the amount of resources for each VNF are determined simultaneously by using MPC so that the amount of resources allocated to VNFs and the number of VNF migrations are minimized. In addition, the performance of data transmission is also controlled by considering the maximum amount of data packets stored in buffers. The performance of the proposed method is evaluated by simulation, and the effectiveness of the proposed method with different parameter values is investigated.

  • On the Asymptotic Evaluation of the Physical Optics Approximation for Plane Wave Scattering by Circular Conducting Cylinders

    Ngoc Quang TA  Hiroshi SHIRAI  

     
    PAPER

      Pubricized:
    2021/10/18
      Vol:
    E105-C No:4
      Page(s):
    128-136

    In this paper, the scattering far-field from a circular electric conducting cylinder has been analyzed by physical optics (PO) approximation for both H and E polarizations. The evaluation of radiation integrations due to the PO current is conducted numerically and analytically. While non-uniform and uniform asymptotic solutions have been derived by the saddle point method, a separate approximation has been made for forward scattering direction. Comparisons among our approximation, direct numerical integration and exact solution results yield a good agreement for electrically large cylinders.

  • Image Super-Resolution via Generative Adversarial Networks Using Metric Projections onto Consistent Sets for Low-Resolution Inputs

    Hiroya YAMAMOTO  Daichi KITAHARA  Hiroki KURODA  Akira HIRABAYASHI  

     
    PAPER-Image

      Pubricized:
    2021/09/29
      Vol:
    E105-A No:4
      Page(s):
    704-718

    This paper addresses single image super-resolution (SR) based on convolutional neural networks (CNNs). It is known that recovery of high-frequency components in output SR images of CNNs learned by the least square errors or least absolute errors is insufficient. To generate realistic high-frequency components, SR methods using generative adversarial networks (GANs), composed of one generator and one discriminator, are developed. However, when the generator tries to induce the discriminator's misjudgment, not only realistic high-frequency components but also some artifacts are generated, and objective indices such as PSNR decrease. To reduce the artifacts in the GAN-based SR methods, we consider the set of all SR images whose square errors between downscaling results and the input image are within a certain range, and propose to apply the metric projection onto this consistent set in the output layers of the generators. The proposed technique guarantees the consistency between output SR images and input images, and the generators with the proposed projection can generate high-frequency components with few artifacts while keeping low-frequency ones as appropriate for the known noise level. Numerical experiments show that the proposed technique reduces artifacts included in the original SR images of a GAN-based SR method while generating realistic high-frequency components with better PSNR values in both noise-free and noisy situations. Since the proposed technique can be integrated into various generators if the downscaling process is known, we can give the consistency to existing methods with the input images without degrading other SR performance.

  • Scaling Law of Energy Efficiency in Intelligent Reflecting Surface Enabled Internet of Things Networks

    Juan ZHAO  Wei-Ping ZHU  

     
    LETTER-Communication Theory and Signals

      Pubricized:
    2021/09/29
      Vol:
    E105-A No:4
      Page(s):
    739-742

    The energy efficiency of intelligent reflecting surface (IRS) enabled internet of things (IoT) networks is studied in this letter. The energy efficiency is mathematically expressed, respectively, as the number of reflecting elements and the spectral efficiency of the network and is shown to scale in the logarithm of the reflecting elements number in the high regime of transmit power from source node. Furthermore, it is revealed that the energy efficiency scales linearly over the spectral efficiency in the high regime of transmit power, in contrast to conventional studies on energy and spectral efficiency trade-offs in the non-IRS wireless IoT networks. Numerical simulations are carried out to verify the derived results for the IRS enabled IoT networks.

  • An Efficient Resource Allocation Using Resource Abstraction for Optical Access Networks for 5G-RAN

    Seiji KOZAKI  Akiko NAGASAWA  Takeshi SUEHIRO  Kenichi NAKURA  Hiroshi MINENO  

     
    PAPER-Network Virtualization

      Pubricized:
    2021/11/22
      Vol:
    E105-B No:4
      Page(s):
    411-420

    In this paper, a novel method of resource abstraction and an abstracted-resource model for dynamic resource control in optical access networks are proposed. Based on this proposal, an implementation assuming application to 5G mobile fronthaul and backhaul is presented. Finally, an evaluation of the processing time for resource allocation using this method is performed using a software prototype of the control function. From the results of the evaluation, it is confirmed that the proposed method offers better characteristics than former approaches, and is suitable for dynamic resource control in 5G applications.

  • Three-Stage Padding Configuration for Sparse Arrays with Larger Continuous Virtual Aperture and Increased Degrees of Freedom

    Abdul Hayee SHAIKH  Xiaoyu DANG  Imran A. KHOSO  Daqing HUANG  

     
    PAPER-Analog Signal Processing

      Pubricized:
    2021/09/08
      Vol:
    E105-A No:3
      Page(s):
    549-561

    A three-stage padding configuration providing a larger continuous virtual aperture and achieving more degrees-of-freedom (DOFs) for the direction-of-arrival (DOA) estimation is presented. The improvement is realized by appropriately cascading three-stages of an identical inter-element spacing. Each stage advantageously exhibits a continuous virtual array, which subsequently produces a hole-free resulting uniform linear array. The geometrical approach remains applicable for any existing sparse array structures with a hole-free coarray, as well as designed in the future. In addition to enlarging the continuous virtual aperture and DOFs, the proposed design offers flexibility so that it can be realized for any given number of antennas. Moreover, a special padding configuration is demonstrated, which further increases the number of continuous virtual sensors. The precise antenna locations and the number of continuous virtual positions are benefited from the closed-form expressions. Experimental works are carried out to demonstrate the effectiveness of the proposed configuration.

  • Anomaly Prediction for Wind Turbines Using an Autoencoder with Vibration Data Supported by Power-Curve Filtering

    Masaki TAKANASHI  Shu-ichi SATO  Kentaro INDO  Nozomu NISHIHARA  Hiroki HAYASHI  Toru SUZUKI  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2021/12/07
      Vol:
    E105-D No:3
      Page(s):
    732-735

    The prediction of the malfunction timing of wind turbines is essential for maintaining the high profitability of the wind power generation industry. Studies have been conducted on machine learning methods that use condition monitoring system data, such as vibration data, and supervisory control and data acquisition (SCADA) data to detect and predict anomalies in wind turbines automatically. Autoencoder-based techniques that use unsupervised learning where the anomaly pattern is unknown have attracted significant interest in the area of anomaly detection and prediction. In particular, vibration data are considered useful because they include the changes that occur in the early stages of a malfunction. However, when autoencoder-based techniques are applied for prediction purposes, in the training process it is difficult to distinguish the difference between operating and non-operating condition data, which leads to the degradation of the prediction performance. In this letter, we propose a method in which both vibration data and SCADA data are utilized to improve the prediction performance, namely, a method that uses a power curve composed of active power and wind speed. We evaluated the method's performance using vibration and SCADA data obtained from an actual wind farm.

  • Activation-Aware Slack Assignment Based Mode-Wise Voltage Scaling for Energy Minimization

    TaiYu CHENG  Yutaka MASUDA  Jun NAGAYAMA  Yoichi MOMIYAMA  Jun CHEN  Masanori HASHIMOTO  

     
    PAPER

      Pubricized:
    2021/08/31
      Vol:
    E105-A No:3
      Page(s):
    497-508

    Reducing power consumption is a crucial factor making industrial designs, such as mobile SoCs, competitive. Voltage scaling (VS) is the classical yet most effective technique that contributes to quadratic power reduction. A recent design technique called activation-aware slack assignment (ASA) enhances the voltage-scaling by allocating the timing margin of critical paths with a stochastic mean-time-to-failure (MTTF) analysis. Meanwhile, such stochastic treatment of timing errors is accepted in limited application domains, such as image processing. This paper proposes a design optimization methodology that achieves a mode-wise voltage-scalable (MWVS) design guaranteeing no timing errors in each mode operation. This work formulates the MWVS design as an optimization problem that minimizes the overall power consumption considering each mode duration, achievable voltage lowering and accompanied circuit overhead explicitly, and explores the solution space with the downhill simplex algorithm that does not require numerical derivation and frequent objective function evaluations. For obtaining a solution, i.e., a design, in the optimization process, we exploit the multi-corner multi-mode design flow in a commercial tool for performing mode-wise ASA with sets of false paths dedicated to individual modes. We applied the proposed design methodology to RISC-V design. Experimental results show that the proposed methodology saves 13% to 20% more power compared to the conventional VS approach and attains 8% to 15% gain from the conventional single-mode ASA. We also found that cycle-by-cycle fine-grained false path identification reduced leakage power by 31% to 42%.

  • FPGA Implementation of a Stream-Based Real-Time Hardware Line Segment Detector

    Taito MANABE  Taichi KATAYAMA  Yuichiro SHIBATA  

     
    PAPER

      Pubricized:
    2021/09/02
      Vol:
    E105-A No:3
      Page(s):
    468-477

    Line detection is the fundamental image processing technique which has various applications in the field of computer vision. For example, lane keeping required to realize autonomous vehicles can be implemented based on line detection technique. For such purposes, however, low detection latency and power consumption are essential. Using hardware-based stream processing is considered as an effective way to achieve such properties since it eliminates the need of storing the whole frame into energy-consuming external memory. In addition, adopting FPGAs enables us to keep flexibility of software processing. The line segment detector (LSD) is the algorithm based on intensity gradient, and performs better than the well-known Hough transform in terms of processing speed and accuracy. However, implementing the original LSD on FPGAs as a pipeline structure is difficult mainly because of its iterative region growing approach. Therefore, we propose a simple and stream-friendly line segment detection algorithm based on the concept of LSD. The whole system is implemented on a Xilinx Zynq-7000 XC7Z020-1CLG400C FPGA without any external memory. Evaluation results reveal that the implemented system is able to detect line segments successfully and is compact with 7.5% of Block RAM and less than 7.0% of the other resources used, while maintaining 60 fps throughput for VGA videos. It is also shown that the system is power-efficient compared to software processing on CPUs.

  • Upper Bound on Privacy-Utility Tradeoff Allowing Positive Excess Distortion Probability Open Access

    Shota SAITO  Toshiyasu MATSUSHIMA  

     
    LETTER-Information Theory

      Pubricized:
    2021/07/14
      Vol:
    E105-A No:3
      Page(s):
    425-427

    This letter investigates the information-theoretic privacy-utility tradeoff. We analyze the minimum information leakage (f-leakage) under the utility constraint that the excess distortion probability is allowed up to ε∈[0, 1). The derived upper bound is characterized by the ε-cutoff random transformation and a distortion ball.

  • Fault Injection Attacks Utilizing Waveform Pattern Matching against Neural Networks Processing on Microcontroller Open Access

    Yuta FUKUDA  Kota YOSHIDA  Takeshi FUJINO  

     
    PAPER

      Pubricized:
    2021/09/22
      Vol:
    E105-A No:3
      Page(s):
    300-310

    Deep learning applications have often been processed in the cloud or on servers. Still, for applications that require privacy protection and real-time processing, the execution environment is moved to edge devices. Edge devices that implement a neural network (NN) are physically accessible to an attacker. Therefore, physical attacks are a risk. Fault attacks on these devices are capable of misleading classification results and can lead to serious accidents. Therefore, we focus on the softmax function and evaluate a fault attack using a clock glitch against NN implemented in an 8-bit microcontroller. The clock glitch is used for fault injection, and the injection timing is controlled by monitoring the power waveform. The specific waveform is enrolled in advance, and the glitch timing pulse is generated by the sum of absolute difference (SAD) matching algorithm. Misclassification can be achieved by appropriately injecting glitches triggered by pattern detection. We propose a countermeasure against fault injection attacks that utilizes the randomization of power waveforms. The SAD matching is disabled by random number initialization on the summation register of the softmax function.

  • Multimodal Prediction of Social Responsiveness Score with BERT-Based Text Features

    Takeshi SAGA  Hiroki TANAKA  Hidemi IWASAKA  Satoshi NAKAMURA  

     
    PAPER

      Pubricized:
    2021/11/02
      Vol:
    E105-D No:3
      Page(s):
    578-586

    Social Skills Training (SST) has been used for years to improve individuals' social skills toward building a better daily life. In SST carried out by humans, the social skills level is usually evaluated through a verbal interview conducted by the trainer. Although this evaluation is based on psychiatric knowledge and professional experience, its quality depends on the trainer's capabilities. Therefore, to standardize such evaluations, quantifiable metrics are required. To meet this need, the second edition of the Social Responsiveness Scale (SRS-2) offers a viable solution because it has been extensively tested and standardized by empirical research works. This paper describes the development of an automated method to evaluate a person's social skills level based on SRS-2. We use multimodal features, including BERT-based features, and perform score estimation with a 0.76 Pearson correlation coefficient while using feature selection. In addition, we examine the linguistic aspects of BERT-based features through subjective evaluations. Consequently, the BERT-based features show a strong negative correlation with human subjective scores of fluency, appropriate word choice, and understandable speech structure.

  • Two-Stage Belief Propagation Detection with MMSE Pre-Cancellation for Overloaded MIMO

    Risa SHIOI  Takashi IMAMURA  Yukitoshi SANADA  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2021/10/15
      Vol:
    E105-B No:3
      Page(s):
    309-317

    In this paper, two-stage BP detection is proposed for overloaded MIMO. The proposal combines BP with the MMSE pre-cancellation algorithm followed by normal BP detection. In overloaded MIMO systems, the loops in a factor graph degrade the demodulation performance of BP detection. MMSE pre-cancellation reduces the number of connections or coefficient values in the factor graph which improves the convergence characteristics of posteriori probabilities. Numerical results obtained through computer simulation show that the BERs of the proposed two-stage BP detection outperforms the conventional BP with MMSE pre-cancellation in a low bit energy range when the MMSE block size is four and the number of MMSE blocks is one. When the pre-cancellation is applied for complexity reduction, the proposed scheme reduces multiplication operations and summation operations by the same factor of 0.7 though the amount of the performance improvement to the conventional scheme is limited.

401-420hit(8214hit)