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  • Conversational AI as a Facilitator Improves Participant Engagement and Problem-Solving in Online Discussion: Sharing Evidence from Five Cities in Afghanistan Open Access

    Sofia SAHAB  Jawad HAQBEEN  Takayuki ITO  

     
    PAPER

      Pubricized:
    2024/01/15
      Vol:
    E107-D No:4
      Page(s):
    434-442

    Despite the increasing use of conversational artificial intelligence (AI) in online discussion environments, few studies explore the application of AI as a facilitator in forming problem-solving debates and influencing opinions in cross-venue scenarios, particularly in diverse and war-ravaged countries. This study aims to investigate the impact of AI on enhancing participant engagement and collaborative problem-solving in online-mediated discussion environments, especially in diverse and heterogeneous discussion settings, such as the five cities in Afghanistan. We seek to assess the extent to which AI participation in online conversations succeeds by examining the depth of discussions and participants' contributions, comparing discussions facilitated by AI with those not facilitated by AI across different venues. The results are discussed with respect to forming and changing opinions with and without AI-mediated communication. The findings indicate that the number of opinions generated in AI-facilitated discussions significantly differs from discussions without AI support. Additionally, statistical analyses reveal quantitative disparities in online discourse sentiments when conversational AI is present compared to when it is absent. These findings contribute to a better understanding of the role of AI-mediated discussions and offer several practical and social implications, paving the way for future developments and improvements.

  • An Automated Multi-Phase Facilitation Agent Based on LLM Open Access

    Yihan DONG  Shiyao DING  Takayuki ITO  

     
    PAPER

      Pubricized:
    2023/12/05
      Vol:
    E107-D No:4
      Page(s):
    426-433

    This paper presents the design and implementation of an automated multi-phase facilitation agent based on LLM to realize inclusive facilitation and efficient use of a large language model (LLM) to facilitate realistic discussions. Large-scale discussion support systems have been studied and implemented very widely since they enable a lot of people to discuss remotely and within 24 hours and 7 days. Furthermore, automated facilitation artificial intelligence (AI) agents have been realized since they can efficiently facilitate large-scale discussions. For example, D-Agree is a large-scale discussion support system where an automated facilitation AI agent facilitates discussion among people. Since the current automated facilitation agent was designed following the structure of the issue-based information system (IBIS) and the IBIS-based agent has been proven that it has superior performance. However, there are several problems that need to be addressed with the IBIS-based agent. In this paper, we focus on the following three problems: 1) The IBIS-based agent was designed to only promote other participants' posts by replying to existing posts accordingly, lacking the consideration of different behaviours taken by participants with diverse characteristics, leading to a result that sometimes the discussion is not sufficient. 2) The facilitation messages generated by the IBIS-based agent were not natural enough, leading to consequences that the participants were not sufficiently promoted and the participants did not follow the flow to discuss a topic. 3) Since the IBIS-based agent is not combined with LLM, designing the control of LLM is necessary. Thus, to solve the problems mentioned above, the design of a phase-based facilitation framework is proposed in this paper. Specifically, we propose two significant designs: One is the design for a multi-phase facilitation agent created based on the framework to address problem 1); The other one is the design for the combination with LLM to address problem 2) and 3). Particularly, the language model called “GPT-3.5” is used for the combination by using corresponding APIs from OPENAI. Furthermore, we demonstrate the improvement of our facilitation agent framework by presenting the evaluations and a case study. Besides, we present the difference between our framework and LangChain which has generic features to utilize LLMs.

  • Design and Fabrication of a Metasurface for Bandwidth Enhancement of RCS Reduction Based on Scattering Cancellation Open Access

    Hiroshi SUENOBU  Shin-ichi YAMAMOTO  Michio TAKIKAWA  Naofumi YONEDA  

     
    PAPER

      Pubricized:
    2023/09/19
      Vol:
    E107-C No:4
      Page(s):
    91-97

    A method for bandwidth enhancement of radar cross section (RCS) reduction by metasurfaces was studied. Scattering cancellation is one of common methods for reducing RCS of target scatterers. It occurs when the wave scattered by the target scatterer and the wave scattered by the canceling scatterer are the same amplitude and opposite phase. Since bandwidth of scattering cancellation is usually narrow, we proposed the bandwidth enhancement method using metasurfaces, which can control the frequency dependence of the scattering phase. We designed and fabricated a metasurface composed of a patch array on a grounded dielectric substrate. Numerical and experimental evaluations confirmed that the metasurface enhances the bandwidth of 10dB RCS reduction by 52% bandwidth ratio of the metasurface from 34% bandwidth ratio of metallic cancelling scatterers.

  • A Lightweight Graph Neural Networks Based Enhanced Separated Detection Scheme for Downlink MIMO-SCMA Systems Open Access

    Zikang CHEN  Wenping GE  Henghai FEI  Haipeng ZHAO  Bowen LI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E107-B No:4
      Page(s):
    368-376

    The combination of multiple-input multiple-output (MIMO) technology and sparse code multiple access (SCMA) can significantly enhance the spectral efficiency of future wireless communication networks. However, the receiver design for downlink MIMO-SCMA systems faces challenges in developing multi-user detection (MUD) schemes that achieve both low latency and low bit error rate (BER). The separated detection scheme in the MIMO-SCMA system involves performing MIMO detection first to obtain estimated signals, followed by SCMA decoding. We propose an enhanced separated detection scheme based on lightweight graph neural networks (GNNs). In this scheme, we raise the concept of coordinate point relay and full-category training, which allow for the substitution of the conventional message passing algorithm (MPA) in SCMA decoding with image classification techniques based on deep learning (DL). The features of the images used for training encompass crucial information such as the amplitude and phase of estimated signals, as well as channel characteristics they have encountered. Furthermore, various types of images demonstrate distinct directional trends, contributing additional features that enhance the precision of classification by GNNs. Simulation results demonstrate that the enhanced separated detection scheme outperforms existing separated and joint detection schemes in terms of computational complexity, while having a better BER performance than the joint detection schemes at high Eb/N0 (energy per bit to noise power spectral density ratio) values.

  • Noise-Robust Scream Detection Using Wave-U-Net Open Access

    Noboru HAYASAKA  Riku KASAI  Takuya FUTAGAMI  

     
    LETTER

      Pubricized:
    2023/10/05
      Vol:
    E107-A No:4
      Page(s):
    634-637

    In this paper, we propose a noise-robust scream detection method with the aim of expanding the scream detection system, a sound-based security system. The proposed method uses enhanced screams using Wave-U-Net, which was effective as a noise reduction method for noisy screams. However, the enhanced screams showed different frequency components from clean screams and erroneously emphasized frequency components similar to scream in noise. Therefore, Wave-U-Net was applied even in the process of training Gaussian mixture models, which are discriminators. We conducted detection experiments using the proposed method in various noise environments and determined that the false acceptance rate was reduced by an average of 2.1% or more compared with the conventional method.

  • Variable-Length Orthogonal Codes over Finite Fields Realizing Data Multiplexing and Error Correction Coding Simultaneously

    Shoichiro YAMASAKI  Tomoko K. MATSUSHIMA  Kyohei ONO  Hirokazu TANAKA  

     
    PAPER-Coding Theory and Techniques

      Pubricized:
    2023/09/26
      Vol:
    E107-A No:3
      Page(s):
    373-383

    The present study proposes a scheme in which variable-length orthogonal codes generated by combining inverse discrete Fourier transform matrices over a finite field multiplex user data into a multiplexed sequence and its sequence forms one or a plural number of codewords for Reed-Solomon coding. The proposed scheme realizes data multiplexing, error correction coding, and multi-rate transmitting at the same time. This study also shows a design example and its performance analysis of the proposed scheme.

  • Collecting Balls on a Line by Robots with Limited Energy

    Tesshu HANAKA  Nicolás HONORATO DROGUETT  Kazuhiro KURITA  Hirotaka ONO  Yota OTACHI  

     
    LETTER

      Pubricized:
    2023/10/10
      Vol:
    E107-D No:3
      Page(s):
    325-327

    In this paper, we study BALL COLLECTING WITH LIMITED ENERGY, which is a problem of scheduling robots with limited energy confined to a line to catch moving balls that eventually cross the line. For this problem, we show the NP-completeness of the general case and some algorithmic results for some cases with a small number of robots.

  • Online Job Scheduling with K Servers

    Xuanke JIANG  Sherief HASHIMA  Kohei HATANO  Eiji TAKIMOTO  

     
    PAPER

      Pubricized:
    2023/11/15
      Vol:
    E107-D No:3
      Page(s):
    286-293

    In this paper, we investigate an online job scheduling problem with n jobs and k servers, where the accessibilities between the jobs and the servers are given as a bipartite graph. The scheduler is tasked with minimizing the regret, defined as the difference between the total flow time of the scheduler over T rounds and that of the best-fixed scheduling in hindsight. We propose an algorithm whose regret bounds are $O(n^2 sqrt{Tln (nk)})$ for general bipartite graphs, $O((n^2/k^{1/2}) sqrt{Tln (nk)})$ for the complete bipartite graphs, and $O((n^2/k) sqrt{T ln (nk)}$ for the disjoint star graphs, respectively. We also give a lower regret bound of $Omega((n^2/k) sqrt{T})$ for the disjoint star graphs, implying that our regret bounds are almost optimal.

  • Precoder Optimization Using Data Correlation for Wireless Data Aggregation

    Ayano NAKAI-KASAI  Naoyuki HAYASHI  Tadashi WADAYAMA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E107-B No:3
      Page(s):
    330-338

    In this paper, we consider precoder design for wireless data aggregation in sensor networks. The precoder optimization problem can be formulated as minimization of mean squared error under transmit power and block diagonal constraints. We include statistical correlation of data into the optimization problem, which is appeared in typical applications but is ignored in conventional designing methods. We propose precoder optimization algorithms based on projected gradient descent with projection onto the constraint sets. The proposed method can achieve better performance than the conventional methods that do not incorporate data correlation, especially when data are highly correlated. We also extend the proposed approach to the context of over-the-air computation.

  • Rotation-Invariant Convolution Networks with Hexagon-Based Kernels

    Yiping TANG  Kohei HATANO  Eiji TAKIMOTO  

     
    PAPER-Biocybernetics, Neurocomputing

      Pubricized:
    2023/11/15
      Vol:
    E107-D No:2
      Page(s):
    220-228

    We introduce the Hexagonal Convolutional Neural Network (HCNN), a modified version of CNN that is robust against rotation. HCNN utilizes a hexagonal kernel and a multi-block structure that enjoys more degrees of rotation information sharing than standard convolution layers. Our structure is easy to use and does not affect the original tissue structure of the network. We achieve the complete rotational invariance on the recognition task of simple pattern images and demonstrate better performance on the recognition task of the rotated MNIST images, synthetic biomarker images and microscopic cell images than past methods, where the robustness to rotation matters.

  • Universal Angle Visibility Realized by a Volumetric 3D Display Using a Rotating Mirror-Image Helix Screen Open Access

    Karin WAKATSUKI  Chiemi FUJIKAWA  Makoto OMODANI  

     
    INVITED PAPER

      Pubricized:
    2023/08/03
      Vol:
    E107-C No:2
      Page(s):
    23-28

    Herein, we propose a volumetric 3D display in which cross-sectional images are projected onto a rotating helix screen. The method employed by this display can enable image observation from universal directions. A major challenge associated with this method is the presence of invisible regions that occur depending on the observation angle. This study aimed to fabricate a mirror-image helix screen with two helical surfaces coaxially arranged in a plane-symmetrical configuration. The visible region was actually measured to be larger than the visible region of the conventional helix screen. We confirmed that the improved visible region was almost independent of the observation angle and that the visible region was almost equally wide on both the left and right sides of the rotation axis.

  • Development and Photoluminescence Properties of Dinuclear Eu(III)-β-Diketonates with a Branched Tetraphosphine Tetraoxide Ligand for Potential Use in LEDs as Red Phosphors Open Access

    Hiroki IWANAGA  Fumihiko AIGA  Shin-ichi SASAOKA  Takahiro WAZAKI  

     
    INVITED PAPER

      Pubricized:
    2023/08/03
      Vol:
    E107-C No:2
      Page(s):
    34-41

    In the field of micro-LED displays consisting of UV or Blue-LED arrays and phosphors, where the chips used are very small, particle size of phosphors must be small to suppress variation in hue for each pixel. Especially, there is a strong demand for a red phosphor with small particle sizes. However, quantum yields of inorganic phosphors decrease as particles size of phosphors get smaller. On the other hand, in the case of organic phosphors and complexes, quantum yields don't decrease when particle size gets smaller because each molecule has a function of absorbing and emitting light. We focus on Eu(III) complexes as candidates of red phosphors for micro-LED displays because their color purities of photoluminescence spectra are high, and have been tried to enhance photoluminescence intensity by coordinating non-ionic ligand, specifically, newly designed phosphine oxide ligands. Non-ionic ligands have generally less influential on properties of complexes compared with ionic ligands, but have a high degree of flexibility in molecular design. We found novel molecular design concept of phosphine oxide ligands to enhance photoluminescence properties of Eu(III) complexes. This time, novel dinuclear Eu(III)-β-diketonates with a branched tetraphosphine tetraoxide ligand, TDPBPO and TDPPPO, were developed. They are designed to have two different phosphine oxide portions; one has aromatic substituents and the other has no aromatic substituent. TDPBPO and TDPPPO ligands have functions of increasing absolute quantum yields of Eu(III)-β-diketonates. Eu(III)-β-diketonates with branched tetraphosphine tetraoxide ligands have sharp red emissions and excellent quantum yields, and are promising candidates for micro LED displays, security media, and sensing for their pure and strong photoluminescence intensity.

  • Re-Evaluating Syntax-Based Negation Scope Resolution

    Asahi YOSHIDA  Yoshihide KATO  Shigeki MATSUBARA  

     
    LETTER-Natural Language Processing

      Pubricized:
    2023/10/16
      Vol:
    E107-D No:1
      Page(s):
    165-168

    Negation scope resolution is the process of detecting the negated part of a sentence. Unlike the syntax-based approach employed in previous researches, state-of-the-art methods performed better without the explicit use of syntactic structure. This work revisits the syntax-based approach and re-evaluates the effectiveness of syntactic structure in negation scope resolution. We replace the parser utilized in the prior works with state-of-the-art parsers and modify the syntax-based heuristic rules. The experimental results demonstrate that the simple modifications enhance the performance of the prior syntax-based method to the same level as state-of-the-art end-to-end neural-based methods.

  • Inference Discrepancy Based Curriculum Learning for Neural Machine Translation

    Lei ZHOU  Ryohei SASANO  Koichi TAKEDA  

     
    PAPER-Natural Language Processing

      Pubricized:
    2023/10/18
      Vol:
    E107-D No:1
      Page(s):
    135-143

    In practice, even a well-trained neural machine translation (NMT) model can still make biased inferences on the training set due to distribution shifts. For the human learning process, if we can not reproduce something correctly after learning it multiple times, we consider it to be more difficult. Likewise, a training example causing a large discrepancy between inference and reference implies higher learning difficulty for the MT model. Therefore, we propose to adopt the inference discrepancy of each training example as the difficulty criterion, and according to which rank training examples from easy to hard. In this way, a trained model can guide the curriculum learning process of an initial model identical to itself. We put forward an analogy to this training scheme as guiding the learning process of a curriculum NMT model by a pretrained vanilla model. In this paper, we assess the effectiveness of the proposed training scheme and take an insight into the influence of translation direction, evaluation metrics and different curriculum schedules. Experimental results on translation benchmarks WMT14 English ⇒ German, WMT17 Chinese ⇒ English and Multitarget TED Talks Task (MTTT) English ⇔ German, English ⇔ Chinese, English ⇔ Russian demonstrate that our proposed method consistently improves the translation performance against the advanced Transformer baseline.

  • Research on Lightweight Acoustic Scene Perception Method Based on Drunkard Methodology

    Wenkai LIU  Lin ZHANG  Menglong WU  Xichang CAI  Hongxia DONG  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2023/10/23
      Vol:
    E107-D No:1
      Page(s):
    83-92

    The goal of Acoustic Scene Classification (ASC) is to simulate human analysis of the surrounding environment and make accurate decisions promptly. Extracting useful information from audio signals in real-world scenarios is challenging and can lead to suboptimal performance in acoustic scene classification, especially in environments with relatively homogeneous backgrounds. To address this problem, we model the sobering-up process of “drunkards” in real-life and the guiding behavior of normal people, and construct a high-precision lightweight model implementation methodology called the “drunkard methodology”. The core idea includes three parts: (1) designing a special feature transformation module based on the different mechanisms of information perception between drunkards and ordinary people, to simulate the process of gradually sobering up and the changes in feature perception ability; (2) studying a lightweight “drunken” model that matches the normal model's perception processing process. The model uses a multi-scale class residual block structure and can obtain finer feature representations by fusing information extracted at different scales; (3) introducing a guiding and fusion module of the conventional model to the “drunken” model to speed up the sobering-up process and achieve iterative optimization and accuracy improvement. Evaluation results on the official dataset of DCASE2022 Task1 demonstrate that our baseline system achieves 40.4% accuracy and 2.284 loss under the condition of 442.67K parameters and 19.40M MAC (multiply-accumulate operations). After adopting the “drunkard” mechanism, the accuracy is improved to 45.2%, and the loss is reduced by 0.634 under the condition of 551.89K parameters and 23.6M MAC.

  • A Novel Trench MOS Barrier Schottky Contact Super Barrier Rectifier

    Peijian ZHANG  Kunfeng ZHU  Wensuo CHEN  

     
    PAPER-Semiconductor Materials and Devices

      Pubricized:
    2023/07/04
      Vol:
    E107-C No:1
      Page(s):
    12-17

    In this paper, a novel trench MOS barrier Schottky contact super barrier rectifier (TMB-SSBR) is proposed by combining the advantages of vertical SSBR and conventional TMBS. The operation mechanism and simulation verification are presented. TMB-SSBR consists of MOS trenches with a vertical SSBR grid which replaces the Schottky diode in the mesa of a TMBS. Due to the presence of top p-n junction in the proposed TMB-SSBR, the image force barrier lowering effect is eliminated, the pinching off electric field effect by MOS trenches is weakened, so that the mesa surface electric field is much larger than that in conventional TMBS. Therefore, the mesa width is enlarged and the n-drift concentration is slightly increased, which results in a low specific on-resistance and a good tradeoff between reverse leakage currents and forward voltages. Compared to a conventional TMBS, simulation results show that, with the same breakdown voltage of 124V and the same reverse leakage current at room temperature, TMB-SSBR increases the figure of merit (FOM, equates to VB2/Ron, sp) by 25.5%, and decreases the reverse leakage by 33.3% at the temperature of 423K. Just like the development from SBD to TMBS, from TMBS to TMB-SSBR also brings obvious improvement of performance.

  • Optimal Design of Wideband mmWave LoS MIMO Systems Using Hybrid Arrays with Beam Squint

    Yongpeng HU  Hang LI  J. Andrew ZHANG  Xiaojing HUANG  Zhiqun CHENG  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2023/09/26
      Vol:
    E107-B No:1
      Page(s):
    244-252

    Analog beamforming with broadband large-scale antenna arrays in millimeter wave (mmWave) multiple input multiple output (MIMO) systems faces the beam squint problem. In this paper, we first investigate the sensitivity of analog beamforming to subarray spatial separations in wideband mmWave systems using hybrid arrays, and propose optimized subarray separations. We then design improved analog beamforming after phase compensation based on Zadoff-Chu (ZC) sequence to flatten the frequency response of radio frequency (RF) equivalent channel. Considering a single-carrier frequency-domain equalization (SC-FDE) scheme at the receiver, we derive low-complexity linear zero-forcing (ZF) and minimum mean squared error (MMSE) equalizers in terms of output signal-to-noise ratio (SNR) after equalization. Simulation results show that the improved analog beamforming can effectively remove frequency-selective deep fading caused by beam squint, and achieve better bit-error-rate performance compared with the conventional analog beamforming.

  • MSLT: A Scalable Solution for Blockchain Network Transport Layer Based on Multi-Scale Node Management Open Access

    Longle CHENG  Xiaofeng LI  Haibo TAN  He ZHAO  Bin YU  

     
    PAPER-Network

      Pubricized:
    2023/09/12
      Vol:
    E107-B No:1
      Page(s):
    185-196

    Blockchain systems rely on peer-to-peer (P2P) overlay networks to propagate transactions and blocks. The node management of P2P networks affects the overall performance and reliability of the system. The traditional structure is based on random connectivity, which is known to be an inefficient operation. Therefore, we propose MSLT, a multiscale blockchain P2P network node management method to improve transaction performance. This approach involves configuring the network to operate at multiple scales, where blockchain nodes are grouped into different ranges at each scale. To minimize redundancy and manage traffic efficiently, neighboring nodes are selected from each range based on a predetermined set of rules. Additionally, a node updating method is implemented to improve the reliability of the network. Compared with existing transmission models in efficiency, utilization, and maximum transaction throughput, the MSLT node management model improves the data transmission performance.

  • Virtualizing DVFS for Energy Minimization of Embedded Dual-OS Platform

    Takumi KOMORI  Yutaka MASUDA  Tohru ISHIHARA  

     
    PAPER

      Pubricized:
    2023/07/12
      Vol:
    E107-A No:1
      Page(s):
    3-15

    Recent embedded systems require both traditional machinery control and information processing, such as network and GUI handling. A dual-OS platform consolidates a real-time OS (RTOS) and general-purpose OS (GPOS) to realize efficient software development on one physical processor. Although the dual-OS platform attracts increasing attention, it often suffers from energy inefficiency in the GPOS for guaranteeing real-time responses of the RTOS. This paper proposes an energy minimization method called DVFS virtualization, which allows running multiple DVFS policies dedicated to the RTOS and GPOS, respectively. The experimental evaluation using a commercial microcontroller showed that the proposed hardware could change the supply voltage within 500 ns and reduce the energy consumption of typical applications by 60 % in the best case compared to conventional dual-OS platforms. Furthermore, evaluation using a commercial microprocessor achieved a 15 % energy reduction of practical open-source software at best.

  • A Fast Intra Mode Decision Algorithm in VVC Based on Feature Cross for Screen Content Videos

    Zhi LIU  Siyuan ZHANG  Xiaohan GUAN  Mengmeng ZHANG  

     
    LETTER-Coding Theory

      Pubricized:
    2023/07/24
      Vol:
    E107-A No:1
      Page(s):
    178-181

    In previous machine learning based fast intra mode decision algorithms for screen content videos, feature design is a key task and it is always difficult to obtain distinguishable features. In this paper, the idea of interaction of features is introduced to fast video coding algorithm, and a fast intra mode decision algorithm based on feature cross is proposed for screen content videos. The numeric features and category features are designed based on the characteristics of screen content videos, and the adaptive factorization network (AFN) is improved and adopted to carry out feature interaction to designed features, and output distinguishable features. The experimental results show that for AI (All Intra) configuration, compared with standard VVC/H.266, the coding time is reduced by 29.64% and the BD rate is increased only by 1.65%.

21-40hit(4570hit)