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161-180hit(30808hit)

  • Video Reflection Removal by Modified EDVR and 3D Convolution Open Access

    Sota MORIYAMA  Koichi ICHIGE  Yuichi HORI  Masayuki TACHI  

     
    LETTER-Image

      Pubricized:
    2023/12/11
      Vol:
    E107-A No:8
      Page(s):
    1430-1434

    In this paper, we propose a method for video reflection removal using a video restoration framework with enhanced deformable networks (EDVR). We examine the effect of each module in EDVR on video reflection removal and modify the models using 3D convolutions. The performance of each modified model is evaluated in terms of the RMSE between the structural similarity (SSIM) and the smoothed SSIM representing temporal consistency.

  • A Dual-Branch Algorithm for Semantic-Focused Face Super-Resolution Reconstruction Open Access

    Qi QI  Liuyi MENG  Ming XU  Bing BAI  

     
    LETTER-Image

      Pubricized:
    2024/03/18
      Vol:
    E107-A No:8
      Page(s):
    1435-1439

    In face super-resolution reconstruction, the interference caused by the texture and color of the hair region on the details and contours of the face region can negatively affect the reconstruction results. This paper proposes a semantic-based, dual-branch face super-resolution algorithm to address the issue of varying reconstruction complexities and mutual interference among different pixel semantics in face images. The algorithm clusters pixel semantic data to create a hierarchical representation, distinguishing between facial pixel regions and hair pixel regions. Subsequently, independent image enhancement is applied to these distinct pixel regions to mitigate their interference, resulting in a vivid, super-resolution face image.

  • Polling Schedule Algorithms for Data Aggregation with Sensor Phase Control in In-Vehicle UWB Networks Open Access

    Hajime MIGITA  Yuki NAKAGOSHI  Patrick FINNERTY  Chikara OHTA  Makoto OKUHARA  

     
    PAPER-Network

      Vol:
    E107-B No:8
      Page(s):
    529-540

    To enhance fuel efficiency and lower manufacturing and maintenance costs, in-vehicle wireless networks can facilitate the weight reduction of vehicle wire harnesses. In this paper, we utilize the Impulse Radio-Ultra Wideband (IR-UWB) of IEEE 802.15.4a/z for in-vehicle wireless networks because of its excellent signal penetration and robustness in multipath environments. Since clear channel assessment is optional in this standard, we employ polling control as a multiple access control to prevent interference within the system. Therein, the preamble overhead is large in IR-UWB of IEEE 802.15.4a/z. Hence, aggregating as much sensor data as possible within each frame is more efficient. In this paper, we assume that reading out data from sensors and sending data to actuators is periodical and that their respective phases can be adjusted. Therefore, this paper proposes an integer linear programming-based scheduling algorithm that minimizes the number of transmitted frames by adjusting the read and write phases. Furthermore, we provide a heuristic algorithm that computes a sub-optimal but acceptable solution in a shorter time. Experimental validation shows that the data aggregation of the proposed algorithms is robust against interference.

  • Differential Active Self-Interference Cancellation for Asynchronous In-Band Full-Duplex GFSK Open Access

    Shinsuke IBI  Takumi TAKAHASHI  Hisato IWAI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E107-B No:8
      Page(s):
    552-563

    This paper proposes a novel differential active self-interference canceller (DASIC) algorithm for asynchronous in-band full-duplex (IBFD) Gaussian filtered frequency shift keying (GFSK), which is designed for wireless Internet of Things (IoT). In IBFD communications, where two terminals simultaneously transmit and receive signals in the same frequency band, there is an extremely strong self-interference (SI). The SI can be mitigated by an active SI canceller (ASIC), which subtracts an interference replica based on channel state information (CSI) from the received signal. The challenging problem is the realization of asynchronous IBFD for wireless IoT in indoor environments. In the asynchronous mode, pilot contamination is induced by the non-orthogonality between asynchronous pilot sequences. In addition, the transceiver suffers from analog front-end (AFE) impairments, such as phase noise. Due to these impairments, the SI cannot be canceled entirely at the receiver, resulting in residual interference. To address the above issue, the DASIC incorporates the principle of the differential codec, which enables to suppress SI without the CSI estimation of SI owing to the differential structure. Also, on the premise of using an error correction technique, iterative detection and decoding (IDD) is applied to improve the detection capability while exchanging the extrinsic log-likelihood ratio (LLR) between the maximum a-posteriori probability (MAP) detector and the channel decoder. Finally, the validity of using the DASIC algorithm is evaluated by computer simulations in terms of the packet error rate (PER). The results clearly demonstrate the possibility of realizing asynchronous IBFD.

  • Sum Rate Maximization for Multiuser Full-Duplex Wireless Powered Communication Networks Open Access

    Keigo HIRASHIMA  Teruyuki MIYAJIMA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E107-B No:8
      Page(s):
    564-572

    In this paper, we consider an orthogonal frequency division multiple access (OFDMA)-based multiuser full-duplex wireless powered communication network (FD WPCN) system with beamforming (BF) at an energy transmitter (ET). The ET performs BF to efficiently transmit energy to multiple users while suppressing interference to an information receiver (IR). Multiple users operating in full-duplex mode harvest energy from the signals sent by the ET while simultaneously transmitting information to the IR using the harvested energy. We analytically demonstrate that the FD WPCN is superior to its half-duplex (HD) WPCN counterpart in the high-SNR regime. We propose a transmitter design method that maximizes the sum rate by determining the BF at the ET, power allocation at both the ET and users, and sub-band allocation. Simulation results show the effectiveness of the proposed method.

  • Method for Estimating Scatterer Information from the Response Waveform of a Backward Transient Scattering Field Using TD-SPT Open Access

    Keiji GOTO  Toru KAWANO  Munetoshi IWAKIRI  Tsubasa KAWAKAMI  Kazuki NAKAZAWA  

     
    PAPER-Electromagnetic Theory

      Pubricized:
    2024/01/23
      Vol:
    E107-C No:8
      Page(s):
    210-222

    This paper proposes a scatterer information estimation method using numerical data for the response waveform of a backward transient scattering field for both E- and H-polarizations when a two-dimensional (2-D) coated metal cylinder is selected as a scatterer. It is assumed that a line source and an observation point are placed at different locations. The four types of scatterer information covered in this paper are the relative permittivity of a surrounding medium, the relative permittivity of a coating medium layer and its thickness, and the radius of a coated metal cylinder. Specifically, a time-domain saddle-point technique (TD-SPT) is used to derive scatterer information estimation formulae from the amplitude intensity ratios (AIRs) of adjacent backward transient scattering field components. The estimates are obtained by substituting the numerical data of the response waveforms of the backward transient scattering field components into the estimation formulae and performing iterative calculations. Furthermore, a minimum thickness of a coating medium layer for which the estimation method is valid is derived, and two kinds of applicable conditions for the estimation method are proposed. The effectiveness of the scatterer information estimation method is verified by comparing the estimates with the set values. The noise tolerance and convergence characteristics of the estimation method and the method of controlling the estimation accuracy are also discussed.

  • 10-Gbit/s Data Transmission Using 120-GHz-Band Contactless Communication with SRR Integrated Glass Substrate Open Access

    Tomohiro KUMAKI  Akihiko HIRATA  Tubasa SAIJO  Yuma KAWAMOTO  Tadao NAGATSUMA  Osamu KAGAYA  

     
    PAPER-Microwaves, Millimeter-Waves

      Pubricized:
    2024/02/08
      Vol:
    E107-C No:8
      Page(s):
    223-230

    We achieved 10-Gbit/s data transmission using a cutting-edge 120-GHz-band high-speed contactless communication technology, which allows seamless connection to a local area network (LAN) by simply placing devices on a desk. We propose a glass substrate-integrated rectangular waveguide that can control the permeability of the top surface to 120-GHz signals by contacting a dielectric substrate with the substrate. The top surface of the rectangular waveguide was replaced with a glass substrate on which split-ring resonators (SRRs) were integrated. The transmission loss of the waveguide with a glass substrate was 2.5 dB at 125 GHz. When a dielectric sheet with a line pattern formed on the contact surface was in contact with a glass substrate, the transmission loss from the waveguide to the dielectric sheet was 19.2 dB at 125 GHz. We achieved 10-Gbit/s data transmission by contacting a dielectric sheet to the SRR-integrated glass substrate.

  • On Easily Reconstructable Logic Functions Open Access

    Tsutomu SASAO  

     
    PAPER

      Pubricized:
    2024/04/16
      Vol:
    E107-D No:8
      Page(s):
    913-921

    This paper shows that sum-of-product expression (SOP) minimization produces the generalization ability. We show this in three steps. First, various classes of SOPs are generated. Second, minterms of SOP are randomly selected to generate partially defined functions. And, third, from the partially defined functions, original functions are reconstructed by SOP minimization. We consider Achilles heel functions, majority functions, monotone increasing cascade functions, functions generated from random SOPs, monotone increasing random SOPs, circle functions, and globe functions. As for the generalization ability, the presented method is compared with Naive Bayes, multi-level perceptron, support vector machine, JRIP, J48, and random forest. For these functions, in many cases, only 10% of the input combinations are sufficient to reconstruct more than 90% of the truth tables of the original functions.

  • Functional Decomposition of Symmetric Multiple-Valued Functions and Their Compact Representation in Decision Diagrams Open Access

    Shinobu NAGAYAMA  Tsutomu SASAO  Jon T. BUTLER  

     
    PAPER

      Pubricized:
    2024/05/14
      Vol:
    E107-D No:8
      Page(s):
    922-929

    This paper proposes a decomposition method for symmetric multiple-valued functions. It decomposes a given symmetric multiple-valued function into three parts. By using suitable decision diagrams for the three parts, we can represent symmetric multiple-valued functions compactly. By deriving theorems on sizes of the decision diagrams, this paper shows that space complexity of the proposed representation is low. This paper also presents algorithms to construct the decision diagrams for symmetric multiple-valued functions with low time complexity. Experimental results show that the proposed method represents randomly generated symmetric multiple-valued functions more compactly than the conventional representation method using standard multiple-valued decision diagrams. Symmetric multiple-valued functions are a basic class of functions, and thus, their compact representation benefits many applications where they appear.

  • New Bounds for Quick Computation of the Lower Bound on the Gate Count of Toffoli-Based Reversible Logic Circuits Open Access

    Takashi HIRAYAMA  Rin SUZUKI  Katsuhisa YAMANAKA  Yasuaki NISHITANI  

     
    PAPER

      Pubricized:
    2024/05/10
      Vol:
    E107-D No:8
      Page(s):
    940-948

    We present a time-efficient lower bound κ on the number of gates in Toffoli-based reversible circuits that represent a given reversible logic function. For the characteristic vector s of a reversible logic function, κ(s) closely approximates σ-lb(s), which is known as a relatively efficient lower bound in respect of evaluation time and tightness. The primary contribution of this paper is that κ enables fast computation while maintaining a tightness of the lower bound, approximately equal to σ-lb. We prove that the discrepancy between κ(s) and σ-lb(s) is at most one only, by providing upper and lower bounds on σ-lb in terms of κ. Subsequently, we show that κ can be calculated more efficiently than σ-lb. An algorithm for κ(s) with a complexity of 𝓞(n) is presented, where n is the dimension of s. Experimental results comparing κ and σ-lb are also given. The results demonstrate that the two lower bounds are equal for most reversible functions, and that the calculation of κ is significantly faster than σ-lb by several orders of magnitude.

  • Extending Binary Neural Networks to Bayesian Neural Networks with Probabilistic Interpretation of Binary Weights Open Access

    Taisei SAITO  Kota ANDO  Tetsuya ASAI  

     
    PAPER

      Pubricized:
    2024/04/17
      Vol:
    E107-D No:8
      Page(s):
    949-957

    Neural networks (NNs) fail to perform well or make excessive predictions when predicting out-of-distribution or unseen datasets. In contrast, Bayesian neural networks (BNNs) can quantify the uncertainty of their inference to solve this problem. Nevertheless, BNNs have not been widely adopted owing to their increased memory and computational cost. In this study, we propose a novel approach to extend binary neural networks by introducing a probabilistic interpretation of binary weights, effectively converting them into BNNs. The proposed approach can reduce the number of weights by half compared to the conventional method. A comprehensive comparative analysis with established methods like Monte Carlo dropout and Bayes by backprop was performed to assess the performance and capabilities of our proposed technique in terms of accuracy and capturing uncertainty. Through this analysis, we aim to provide insights into the advantages of this Bayesian extension.

  • Error-Tolerance-Aware Write-Energy Reduction of MTJ-Based Quantized Neural Network Hardware Open Access

    Ken ASANO  Masanori NATSUI  Takahiro HANYU  

     
    PAPER

      Pubricized:
    2024/04/22
      Vol:
    E107-D No:8
      Page(s):
    958-965

    The development of energy-efficient neural network hardware using magnetic tunnel junction (MTJ) devices has been widely investigated. One of the issues in the use of MTJ devices is large write energy. Since MTJ devices show stochastic behaviors, a large write current with enough time length is required to guarantee the certainty of the information held in MTJ devices. This paper demonstrates that quantized neural networks (QNNs) exhibit high tolerance to bit errors in weights and an output feature map. Since probabilistic switching errors in MTJ devices do not have always a serious effect on the performance of QNNs, large write energy is not required for reliable switching operations of MTJ devices. Based on the evaluation results, we achieve about 80% write-energy reduction on buffer memory compared to the conventional method. In addition, it is demonstrated that binary representation exhibits higher bit-error tolerance than the other data representations in the range of large error rates.

  • Delta-Sigma Domain Signal Processing Revisited with Related Topics in Stochastic Computing Open Access

    Takao WAHO  Akihisa KOYAMA  Hitoshi HAYASHI  

     
    PAPER

      Pubricized:
    2024/04/17
      Vol:
    E107-D No:8
      Page(s):
    966-975

    Signal processing using delta-sigma modulated bit streams is reviewed, along with related topics in stochastic computing (SC). The basic signal processing circuits, adders and multipliers, are covered. In particular, the possibility of preserving the noise-shaping properties inherent in delta-sigma modulation during these operations is discussed. Finally, the root mean square error for addition and multiplication is evaluated, and the performance improvement of signal processing in the delta-sigma domain compared with SC is verified.

  • Evaluation of Multi-Valued Data Transmission in Two-Dimensional Symbol Mapping using Linear Mixture Model Open Access

    Yosuke IIJIMA  Atsunori OKADA  Yasushi YUMINAKA  

     
    PAPER

      Pubricized:
    2024/05/09
      Vol:
    E107-D No:8
      Page(s):
    976-984

    In high-speed data communication systems, it is important to evaluate the quality of the transmitted signal at the receiver. At a high-speed data rate, the transmission line characteristics act as a high-frequency attenuator and contribute to the intersymbol interference (ISI) at the receiver. To evaluate ISI conditions, eye diagrams are widely used to analyze signal quality and visualize the ISI effect as an eye-opening rate. Various types of on-chip eye-opening monitors (EOM) have been proposed to adjust waveform-shaping circuits. However, the eye diagram evaluation of multi-valued signaling becomes more difficult than that of binary transmission because of the complicated signal transition patterns. Moreover, in severe ISI situations where the eye is completely closed, eye diagram evaluation does not work well. This paper presents a novel evaluation method using Two-dimensional(2D) symbol mapping and a linear mixture model (LMM) for multi-valued data transmission. In our proposed method, ISI evaluation can be realized by 2D symbol mapping, and an efficient quantitative analysis can be realized using the LMM. An experimental demonstration of four leveled pulse amplitude modulation(PAM-4) data transmission using a Cat5e cable 100 m is presented. The experimental results show that the proposed method can extract features of the ISI effect even though the eye is completely closed in the server condition.

  • Evaluating PAM-4 Data Transmission Quality Using Multi-Dimensional Mapping of Received Symbols Open Access

    Yasushi YUMINAKA  Kazuharu NAKAJIMA  Yosuke IIJIMA  

     
    PAPER

      Pubricized:
    2024/04/25
      Vol:
    E107-D No:8
      Page(s):
    985-991

    This study investigates a two/three-dimensional (2D/3D) symbol-mapping technique that evaluates data transmission quality based on a four-level pulse-amplitude modulation (PAM-4) symbol transition. Multi-dimensional symbol transition mapping facilitates the visualization of the degree of interference (ISI). The simulation and experimental results demonstrated that the 2D symbol mapping can evaluate the PAM-4 data transmission quality degraded by ISI and visualize the equalization effect. Furthermore, potential applications of 2D mapping and its extension to 3D mapping were explored.

  • Unveiling Python Version Compatibility Challenges in Code Snippets on Stack Overflow Open Access

    Shiyu YANG  Tetsuya KANDA  Daniel M. GERMAN  Yoshiki HIGO  

     
    PAPER-Software Engineering

      Pubricized:
    2024/04/16
      Vol:
    E107-D No:8
      Page(s):
    1007-1015

    Stack Overflow, a leading Q&A platform for developers, is a substantial reservoir of Python code snippets. Nevertheless, the incompatibility issues between Python versions, particularly Python 2 and Python 3, introduce substantial challenges that can potentially jeopardize the utility of these code snippets. This empirical study dives deep into the challenges of Python version inconsistencies on the interpretation and application of Python code snippets on Stack Overflow. Our empirical study exposes the prevalence of Python version compatibility issues on Stack Overflow. It further emphasizes an apparent deficiency in version-specific identification, a critical element that facilitates the identification and utilization of Python code snippets. These challenges, primarily arising from the lack of backward compatibility between Python’s major versions, pose significant hurdles for developers relying on Stack Overflow for code references and learning. This study, therefore, signifies the importance of proactively addressing these compatibility issues in Python code snippets. It advocates for enhanced tools and strategies to assist developers in efficiently navigating through the Python version complexities on platforms like Stack Overflow. By highlighting these concerns and providing a potential remedy, we aim to contribute to a more efficient and effective programming experience on Stack Overflow and similar platforms.

  • Investigating and Enhancing the Neural Distinguisher for Differential Cryptanalysis Open Access

    Gao WANG  Gaoli WANG  Siwei SUN  

     
    PAPER-Information Network

      Pubricized:
    2024/04/12
      Vol:
    E107-D No:8
      Page(s):
    1016-1028

    At Crypto 2019, Gohr first adopted the neural distinguisher for differential cryptanalysis, and since then, this work received increasing attention. However, most of the existing work focuses on improving and applying the neural distinguisher, the studies delving into the intrinsic principles of neural distinguishers are finite. At Eurocrypt 2021, Benamira et al. conducted a study on Gohr’s neural distinguisher. But for the neural distinguishers proposed later, such as the r-round neural distinguishers trained with k ciphertext pairs or ciphertext differences, denoted as NDcpk_r (Gohr’s neural distinguisher is the special NDcpk_r with K = 1) and NDcdk_r , such research is lacking. In this work, we devote ourselves to study the intrinsic principles and relationship between NDcdk_r and NDcpk_r. Firstly, we explore the working principle of NDcd1_r through a series of experiments and find that it strongly relies on the probability distribution of ciphertext differences. Its operational mechanism bears a strong resemblance to that of NDcp1_r given by Benamira et al.. Therefore, we further compare them from the perspective of differential cryptanalysis and sample features, demonstrating the superior performance of NDcp1_r can be attributed to the relationships between certain ciphertext bits, especially the significant bits. We then extend our investigation to NDcpk_r, and show that its ability to recognize samples heavily relies on the average differential probability of k ciphertext pairs and some relationships in the ciphertext itself, but the reliance between k ciphertext pairs is very weak. Finally, in light of the findings of our research, we introduce a strategy to enhance the accuracy of the neural distinguisher by using a fixed difference to generate the negative samples instead of the random one. Through the implementation of this approach, we manage to improve the accuracy of the neural distinguishers by approximately 2% to 8% for 7-round Speck32/64 and 9-round Simon32/64.

  • Confidence-Driven Contrastive Learning for Document Classification without Annotated Data Open Access

    Zhewei XU  Mizuho IWAIHARA  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2024/04/19
      Vol:
    E107-D No:8
      Page(s):
    1029-1039

    Data sparsity has always been a problem in document classification, for which semi-supervised learning and few-shot learning are studied. An even more extreme scenario is to classify documents without any annotated data, but using only category names. In this paper, we introduce a nearest neighbor search-based method Con2Class to tackle this tough task. We intend to produce embeddings for predefined categories and predict category embeddings for all the unlabeled documents in a unified embedding space, such that categories can be easily assigned by searching the nearest predefined category in the embedding space. To achieve this, we propose confidence-driven contrastive learning, in which prompt-based templates are designed and MLM-maintained contrastive loss is newly proposed to finetune a pretrained language model for embedding production. To deal with the issue that no annotated data is available to validate the classification model, we introduce confidence factor to estimate the classification ability by evaluating the prediction confidence. The language model having the highest confidence factor is used to produce embeddings for similarity evaluation. Pseudo labels are then assigned by searching the semantically closest category name, which are further used to train a separate classifier following a progressive self-training strategy for final prediction. Our experiments on five representative datasets demonstrate the superiority of our proposed method over the existing approaches.

  • Agent Allocation-Action Learning with Dynamic Heterogeneous Graph in Multi-Task Games Open Access

    Xianglong LI  Yuan LI  Jieyuan ZHANG  Xinhai XU  Donghong LIU  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2024/04/03
      Vol:
    E107-D No:8
      Page(s):
    1040-1049

    In many real-world problems, a complex task is typically composed of a set of subtasks that follow a certain execution order. Traditional multi-agent reinforcement learning methods perform poorly in such multi-task cases, as they consider the whole problem as one task. For such multi-agent multi-task problems, heterogeneous relationships i.e., subtask-subtask, agent-agent, and subtask-agent, are important characters which should be explored to facilitate the learning performance. This paper proposes a dynamic heterogeneous graph based agent allocation-action learning framework. Specifically, a dynamic heterogeneous graph model is firstly designed to characterize the variation of heterogeneous relationships with the time going on. Then a multi-subgraph partition method is invented to extract features of heterogeneous graphs. Leveraging the extracted features, a hierarchical framework is designed to learn the dynamic allocation of agents among subtasks, as well as cooperative behaviors. Experimental results demonstrate that our framework outperforms recent representative methods on two challenging tasks, i.e., SAVETHECITY and Google Research Football full game.

  • Machine Learning-Based System for Heat-Resistant Analysis of Car Lamp Design Open Access

    Hyebong CHOI  Joel SHIN  Jeongho KIM  Samuel YOON  Hyeonmin PARK  Hyejin CHO  Jiyoung JUNG  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2024/04/03
      Vol:
    E107-D No:8
      Page(s):
    1050-1058

    The design of automobile lamps requires accurate estimation of heat distribution to prevent overheating and deformation of the product. Traditional heat resistant analysis using Computational Fluid Dynamics (CFD) is time-consuming and requires expertise in thermofluid mechanics, making real-time temperature analysis less accessible to lamp designers. We propose a machine learning-based temperature prediction system for automobile lamp design. We trained our machine learning models using CFD results of various lamp designs, providing lamp designers real-time Heat-Resistant Analysis. Comprehensive tests on real lamp products demonstrate that our prediction model accurately estimates heat distribution comparable to CFD analysis within a minute. Our system visualizes the estimated heat distribution of car lamp design supporting quick decision-making by lamp designer. It is expected to shorten the product design process, improving the market competitiveness.

161-180hit(30808hit)