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  • Four Classes of Bivariate Permutation Polynomials over Finite Fields of Even Characteristic Open Access

    Changhui CHEN  Haibin KAN  Jie PENG  Li WANG  

     
    LETTER-Cryptography and Information Security

      Pubricized:
    2023/10/17
      Vol:
    E107-A No:7
      Page(s):
    1045-1048

    Permutation polynomials have important applications in cryptography, coding theory and combinatorial designs. In this letter, we construct four classes of permutation polynomials over 𝔽2n × 𝔽2n, where 𝔽2n is the finite field with 2n elements.

  • Dance-Conditioned Artistic Music Generation by Creative-GAN Open Access

    Jiang HUANG  Xianglin HUANG  Lifang YANG  Zhulin TAO  

     
    PAPER-Multimedia Environment Technology

      Pubricized:
    2023/08/23
      Vol:
    E107-A No:5
      Page(s):
    836-844

    We present a novel adversarial, end-to-end framework based on Creative-GAN to generate artistic music conditioned on dance videos. Our proposed framework takes the visual and motion posture data as input, and then adopts a quantized vector as the audio representation to generate complex music corresponding to input. However, the GAN algorithm just imitate and reproduce works what humans have created, instead of generating something new and creative. Therefore, we newly introduce Creative-GAN, which extends the original GAN framework to two discriminators, one is to determine whether it is real music, and the other is to classify music style. The paper shows that our proposed Creative-GAN can generate novel and interesting music which is not found in the training dataset. To evaluate our model, a comprehensive evaluation scheme is introduced to make subjective and objective evaluation. Compared with the advanced methods, our experimental results performs better in measureing the music rhythm, generation diversity, dance-music correlation and overall quality of generated music.

  • Implementing Optical Analog Computing and Electrooptic Hopfield Network by Silicon Photonic Circuits Open Access

    Guangwei CONG  Noritsugu YAMAMOTO  Takashi INOUE  Yuriko MAEGAMI  Morifumi OHNO  Shota KITA  Rai KOU  Shu NAMIKI  Koji YAMADA  

     
    INVITED PAPER

      Pubricized:
    2024/01/05
      Vol:
    E107-A No:5
      Page(s):
    700-708

    Wide deployment of artificial intelligence (AI) is inducing exponentially growing energy consumption. Traditional digital platforms are becoming difficult to fulfill such ever-growing demands on energy efficiency as well as computing latency, which necessitates the development of high efficiency analog hardware platforms for AI. Recently, optical and electrooptic hybrid computing is reactivated as a promising analog hardware alternative because it can accelerate the information processing in an energy-efficient way. Integrated photonic circuits offer such an analog hardware solution for implementing photonic AI and machine learning. For this purpose, we proposed a photonic analog of support vector machine and experimentally demonstrated low-latency and low-energy classification computing, which evidences the latency and energy advantages of optical analog computing over traditional digital computing. We also proposed an electrooptic Hopfield network for classifying and recognizing time-series data. This paper will review our work on implementing classification computing and Hopfield network by leveraging silicon photonic circuits.

  • Transmission Performance Evaluation of Local 5G Downlink Data Channel in SU-MIMO System under Outdoor Environments

    Hiroki URASAWA  Hayato SOYA  Kazuhiro YAMAGUCHI  Hideaki MATSUE  

     
    PAPER

      Pubricized:
    2023/10/11
      Vol:
    E107-B No:1
      Page(s):
    63-73

    We evaluated the transmission performance, including received power and transmission throughput characteristics, in 4×4 single-user multiple-input multiple-output (SU-MIMO) transmission for synchronous time division duplex (TDD) and downlink data channels in comparison with single-input single-output (SISO) transmission in an environment where a local 5G wireless base station was installed on the roof of a research building at our university. Accordingly, for the received power characteristics, the difference between the simulation value, which was based on the ray tracing method, and the experimental value at 32 points in the area was within a maximum difference of approximately 10 dB, and sufficient compliance was obtained. Regarding the transmission throughput versus received power characteristics, after showing a simulation method for evaluating throughput characteristics in MIMO, we compared the results with experimental results. The cumulative distribution function (CDF) of the transmission throughput shows that, at a CDF of 50%, in SISO transmission, the simulated value is approximately 115Mbps, and the experimental value is 105Mbps, within a difference of approximately 10Mbps. By contrast, in MIMO transmission, the simulation value is 380Mbps, and the experimental value is approximately 420Mbps, which is a difference of approximately 40Mbps. It was shown that the received power and transmission throughput characteristics can be predicted with sufficient accuracy by obtaining the delay profile and the system model at each reception point using the both ray tracing and MIMO simulation methods in actual environments.

  • Upper Bound for the Coefficients of the Shortest Vector of Random Lattice

    Masahiro KAMINAGA  

     
    LETTER-Cryptography and Information Security

      Pubricized:
    2023/05/30
      Vol:
    E106-A No:12
      Page(s):
    1585-1588

    This paper shows that upper bounds on the coefficients of the shortest vector of a lattice can be represented using the smallest eigenvalue of the Gram matrix for the lattice, obtains its distribution for high-dimensional random Goldstein-Mayer lattice, and applies it to determine the percentage of zeros of coefficient vector.

  • Comments on Quasi-Linear Support Vector Machine for Nonlinear Classification

    Sei-ichiro KAMATA  Tsunenori MINE  

     
    WRITTEN DISCUSSION-General Fundamentals and Boundaries

      Pubricized:
    2023/05/08
      Vol:
    E106-A No:11
      Page(s):
    1444-1445

    In 2014, the above paper entitled ‘Quasi-Linear Support Vector Machine for Nonlinear Classification’ was published by Zhou, et al. [1]. They proposed a quasi-linear kernel function for support vector machine (SVM). However, in this letter, we point out that this proposed kernel function is a part of multiple kernel functions generated by well-known multiple kernel learning which is proposed by Bach, et al. [2] in 2004. Since then, there have been a lot of related papers on multiple kernel learning with several applications [3]. This letter verifies that the main kernel function proposed by Zhou, et al. [1] can be derived using multiple kernel learning algorithms [3]. In the kernel construction, Zhou, et al. [1] used Gaussian kernels, but the multiple kernel learning had already discussed the locality of additive Gaussian kernels or other kernels in the framework [4], [5]. Especially additive Gaussian or other kernels were discussed in tutorial at major international conference ECCV2012 [6]. The authors did not discuss these matters.

  • Authors' Reply to the Comments by Kamata et al.

    Bo ZHOU  Benhui CHEN  Jinglu HU  

     
    WRITTEN DISCUSSION

      Pubricized:
    2023/05/08
      Vol:
    E106-A No:11
      Page(s):
    1446-1449

    We thank Kamata et al. (2023) [1] for their interest in our work [2], and for providing an explanation of the quasi-linear kernel from a viewpoint of multiple kernel learning. In this letter, we first give a summary of the quasi-linear SVM. Then we provide a discussion on the novelty of quasi-linear kernels against multiple kernel learning. Finally, we explain the contributions of our work [2].

  • Variable-Gain Phase Shifter with Phase Compensation Using Varactors

    Akihito HIRAI  Yuki TSUKUI  Koji TSUTSUMI  Kazutomi MORI  

     
    PAPER

      Pubricized:
    2023/05/12
      Vol:
    E106-C No:11
      Page(s):
    677-688

    This paper demonstrates a phase compensation technique using varactors for variable-gain phase shifters (VGPSs). The VGPS consists of an I/Q generator and I/Q variable gain amplifiers (I/Q VGAs). I/Q VGAs based on common-emitter stages are enabled to control the gain by adjusting the collector current of the transistor. However, the phase control performance degenerates because the input capacitance varies with the collector current. The proposed phase compensation technique reduces the variation in the insertion phase of the I/Q VGA by adjusting the voltage of the varactor provided at its input and maintaining the input capacitance constant in any gain state. As a result, the VGPS can provide a low phase and amplitude error under phase control. A Ka-band VGPS with the proposed phase compensation technique, fabricated in a 130-nm SiGe BiCMOS process, demonstrates a 0.73° and 0.06 dB improvement in the RMS phase and amplitude error compared with the case without the compensation technique. The VGPS achieves measured RMS amplitude and phase errors of less than 0.19 dB and 0.75°, respectively, in an amplitude control range of more than 20 dB with a frequency range of 28 to 32 GHz.

  • Further Results on Autocorrelation of Vectorial Boolean Functions

    Zeyao LI  Niu JIANG  Zepeng ZHUO  

     
    PAPER-Cryptography and Information Security

      Pubricized:
    2023/03/27
      Vol:
    E106-A No:10
      Page(s):
    1305-1310

    In this paper, we study the properties of the sum-of-squares indicator of vectorial Boolean functions. Firstly, we give the upper bound of $sum_{uin mathbb{F}_2^n,vin mathbb{F}_2^m}mathcal{W}_F^3(u,v)$. Secondly, based on the Walsh-Hadamard transform, we give a secondary construction of vectorial bent functions. Further, three kinds of sum-of-squares indicators of vectorial Boolean functions are defined by autocorrelation function and the lower and upper bounds of the sum-of-squares indicators are derived. Finally, we study the sum-of-squares indicators with respect to several equivalence relations, and get the sum-of-squares indicator which have the best cryptographic properties.

  • An Accuracy Reconfigurable Vector Accelerator based on Approximate Logarithmic Multipliers for Energy-Efficient Computing

    Lingxiao HOU  Yutaka MASUDA  Tohru ISHIHARA  

     
    PAPER

      Pubricized:
    2022/09/02
      Vol:
    E106-A No:3
      Page(s):
    532-541

    The approximate logarithmic multiplier proposed by Mitchell provides an efficient alternative for processing dense multiplication or multiply-accumulate operations in applications such as image processing and real-time robotics. It offers the advantages of small area, high energy efficiency and is suitable for applications that do not necessarily achieve high accuracy. However, its maximum error of 11.1% makes it challenging to deploy in applications requiring relatively high accuracy. This paper proposes a novel operand decomposition method (OD) that decomposes one multiplication into the sum of multiple approximate logarithmic multiplications to widely reduce Mitchell multiplier errors while taking full advantage of its area savings. Based on the proposed OD method, this paper also proposes an accuracy reconfigurable multiply-accumulate (MAC) unit that provides multiple reconfigurable accuracies with high parallelism. Compared to a MAC unit consisting of accurate multipliers, the area is significantly reduced to less than half, improving the hardware parallelism while satisfying the required accuracy for various scenarios. The experimental results show the excellent applicability of our proposed MAC unit in image smoothing and robot localization and mapping application. We have also designed a prototype processor that integrates the minimum functionality of this MAC unit as a vector accelerator and have implemented a software-level accuracy reconfiguration in the form of an instruction set extension. We experimentally confirmed the correct operation of the proposed vector accelerator, which provides the different degrees of accuracy and parallelism at the software level.

  • On the Number of Affine Equivalence Classes of Vectorial Boolean Functions and q-Ary Functions

    Shihao LU  Haibin KAN  Jie PENG  Chenmiao SHI  

     
    PAPER-Cryptography and Information Security

      Pubricized:
    2022/08/24
      Vol:
    E106-A No:3
      Page(s):
    600-605

    Vectorial Boolean functions play an important role in cryptography, sequences and coding theory. Both affine equivalence and EA-equivalence are well known equivalence relations between vectorial Boolean functions. In this paper, we give an exact formula for the number of affine equivalence classes, and an asymptotic formula for the number of EA-equivalence classes of vectorial Boolean functions.

  • Study on Wear Debris Distribution and Performance Degradation in Low Frequency Fretting Wear of Electrical Connector

    Yanyan LUO  Jingzhao AN  Jingyuan SU  Zhaopan ZHANG  Yaxin DUAN  

     
    PAPER-Electromechanical Devices and Components

      Pubricized:
    2022/10/13
      Vol:
    E106-C No:3
      Page(s):
    93-102

    Aiming at the problem of the deterioration of the contact performance caused by the wear debris generated during the fretting wear of the electrical connector, low-frequency fretting wear experiments were carried out on the contacts of electrical connectors, the accumulation and distribution of the wear debris were detected by the electrical capacitance tomography technology; the influence of fretting cycles, vibration direction, vibration frequency and vibration amplitude on the accumulation and distribution of wear debris were analyzed; the correlation between characteristic value of wear debris and contact resistance value was studied, and a performance degradation model based on the accumulation and distribution of wear debris was built. The results show that fretting wear and performance degradation are the most serious in axial vibration; the characteristic value of wear debris and contact resistance are positively correlated with the fretting cycles, vibration frequency and vibration amplitude; there is a strong correlation between the sum of characteristic value of wear debris and the contact resistance value; the prediction error of ABC-SVR model of fretting wear performance degradation of electrical connectors constructed by the characteristic value of wear debris is less than 6%. Therefore, the characteristic value of wear debris in contact subareas can quantitatively describe the degree of fretting wear and the process of performance degradation.

  • A Spectral-Based Model for Describing Social Polarization in Online Communities Open Access

    Tomoya KINOSHITA  Masaki AIDA  

     
    PAPER

      Pubricized:
    2022/07/13
      Vol:
    E105-B No:10
      Page(s):
    1181-1191

    The phenomenon known as social polarization, in which a social group splits into two or more groups, can cause division of the society by causing the radicalization of opinions and the spread of misinformation, is particularly significant in online communities. To develop technologies to mitigate the effects of polarization in online social networks, it is necessary to understand the mechanism driving its occurrence. There are some models of social polarization in which network structure and users' opinions change, based on the quantified opinions held by the users of online social networks. However, they are based on the interaction between users connected by online social networks. Current recommendation systems offer information from unknown users who are deemed to have similar interests. We can interpret this situation as being yielded non-local effects brought on by the network system, it is not based on local interactions between users. In this paper, based on the spectral graph theory, which can describe non-local effects in online social networks mathematically, we propose a model of polarization that user behavior and network structure change while influencing each other including non-local effects. We investigate the characteristics of the proposed model. Simultaneously, we propose an index to evaluate the degree of network polarization quantitatively, which is needed for our investigations.

  • Frank-Wolfe for Sign-Constrained Support Vector Machines

    Kenya TAJIMA  Takahiko HENMI  Tsuyoshi KATO  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2022/06/27
      Vol:
    E105-D No:10
      Page(s):
    1734-1742

    Domain knowledge is useful to improve the generalization performance of learning machines. Sign constraints are a handy representation to combine domain knowledge with learning machine. In this paper, we consider constraining the signs of the weight coefficients in learning the linear support vector machine, and develop an optimization algorithm for minimizing the empirical risk under the sign constraints. The algorithm is based on the Frank-Wolfe method that also converges sublinearly and possesses a clear termination criterion. We show that each iteration of the Frank-Wolfe also requires O(nd+d2) computational cost. Furthermore, we derive the explicit expression for the minimal iteration number to ensure an ε-accurate solution by analyzing the curvature of the objective function. Finally, we empirically demonstrate that the sign constraints are a promising technique when similarities to the training examples compose the feature vector.

  • Analysis on Norms of Word Embedding and Hidden Vectors in Neural Conversational Model Based on Encoder-Decoder RNN

    Manaya TOMIOKA  Tsuneo KATO  Akihiro TAMURA  

     
    PAPER-Natural Language Processing

      Pubricized:
    2022/06/30
      Vol:
    E105-D No:10
      Page(s):
    1780-1789

    A neural conversational model (NCM) based on an encoder-decoder recurrent neural network (RNN) with an attention mechanism learns different sequence-to-sequence mappings from what neural machine translation (NMT) learns even when based on the same technique. In the NCM, we confirmed that target-word-to-source-word mappings captured by the attention mechanism are not as clear and stationary as those for NMT. Considering that vector norms indicate a magnitude of information in the processing, we analyzed the inner workings of an encoder-decoder GRU-based NCM focusing on the norms of word embedding vectors and hidden vectors. First, we conducted correlation analyses on the norms of word embedding vectors with frequencies in the training set and with conditional entropies of a bi-gram language model to understand what is correlated with the norms in the encoder and decoder. Second, we conducted correlation analyses on norms of change in the hidden vector of the recurrent layer with their input vectors for the encoder and decoder, respectively. These analyses were done to understand how the magnitude of information propagates through the network. The analytical results suggested that the norms of the word embedding vectors are associated with their semantic information in the encoder, while those are associated with the predictability as a language model in the decoder. The analytical results further revealed how the norms propagate through the recurrent layer in the encoder and decoder.

  • In Search of the Performance- and Energy-Efficient CNN Accelerators Open Access

    Stanislav SEDUKHIN  Yoichi TOMIOKA  Kohei YAMAMOTO  

     
    PAPER

      Pubricized:
    2021/12/03
      Vol:
    E105-C No:6
      Page(s):
    209-221

    In this paper, starting from the algorithm, a performance- and energy-efficient 3D structure or shape of the Tensor Processing Engine (TPE) for CNN acceleration is systematically searched and evaluated. An optimal accelerator's shape maximizes the number of concurrent MAC operations per clock cycle while minimizes the number of redundant operations. The proposed 3D vector-parallel TPE architecture with an optimal shape can be very efficiently used for considerable CNN acceleration. Due to implemented support of inter-block image data independency, it is possible to use multiple of such TPEs for the additional CNN acceleration. Moreover, it is shown that the proposed TPE can also be uniformly used for acceleration of the different CNN models such as VGG, ResNet, YOLO, and SSD. We also demonstrate that our theoretical efficiency analysis is matched with the result of a real implementation for an SSD model to which a state-of-the-art channel pruning technique is applied.

  • SVM Based Intrusion Detection Method with Nonlinear Scaling and Feature Selection

    Fei ZHANG  Peining ZHEN  Dishan JING  Xiaotang TANG  Hai-Bao CHEN  Jie YAN  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2022/02/14
      Vol:
    E105-D No:5
      Page(s):
    1024-1038

    Intrusion is one of major security issues of internet with the rapid growth in smart and Internet of Thing (IoT) devices, and it becomes important to detect attacks and set out alarm in IoT systems. In this paper, the support vector machine (SVM) and principal component analysis (PCA) based method is used to detect attacks in smart IoT systems. SVM with nonlinear scheme is used for intrusion classification and PCA is adopted for feature selection on the training and testing datasets. Experiments on the NSL-KDD dataset show that the test accuracy of the proposed method can reach 82.2% with 16 features selected from PCA for binary-classification which is almost the same as the result obtained with all the 41 features; and the test accuracy can achieve 78.3% with 29 features selected from PCA for multi-classification while 79.6% without feature selection. The Denial of Service (DoS) attack detection accuracy of the proposed method can achieve 8.8% improvement compared with existing artificial neural network based method.

  • Vector Quantization of Speech Spectrum Based on the VQ-VAE Embedding Space Learning by GAN Technique

    Tanasan SRIKOTR  Kazunori MANO  

     
    PAPER-Speech and Hearing, Digital Signal Processing

      Pubricized:
    2021/09/30
      Vol:
    E105-A No:4
      Page(s):
    647-654

    The spectral envelope parameter is a significant speech parameter in the vocoder's quality. Recently, the Vector Quantized Variational AutoEncoder (VQ-VAE) is a state-of-the-art end-to-end quantization method based on the deep learning model. This paper proposed a new technique for improving the embedding space learning of VQ-VAE with the Generative Adversarial Network for quantizing the spectral envelope parameter, called VQ-VAE-EMGAN. In experiments, we designed the quantizer for the spectral envelope parameters of the WORLD vocoder extracted from the 16kHz speech waveform. As the results shown, the proposed technique reduced the Log Spectral Distortion (LSD) around 0.5dB and increased the PESQ by around 0.17 on average for four target bit operations compared to the conventional VQ-VAE.

  • Spatial Vectors Effective for Nakagami-m Fading MIMO Channels Open Access

    Tatsumi KONISHI  Hiroyuki NAKANO  Yoshikazu YANO  Michihiro AOKI  

     
    LETTER-Communication Theory and Signals

      Pubricized:
    2021/08/03
      Vol:
    E105-A No:3
      Page(s):
    428-432

    This letter proposes a transmission scheme called spatial vector (SV), which is effective for Nakagami-m fading multiple-input multiple-output channels. First, the analytical error rate of SV is derived for Nakagami-m fading MIMO channels. Next, an example of SV called integer SV (ISV) is introduced. The error performance was evaluated over Nakagami-m fading from m = 1 to m = 50 and compared with spatial modulation (SM), enhanced SM, and quadrature SM. The results show that for m > 1, ISV outperforms the SM schemes and is robust to m variations.

  • Feasibility Study for Computer-Aided Diagnosis System with Navigation Function of Clear Region for Real-Time Endoscopic Video Image on Customizable Embedded DSP Cores

    Masayuki ODAGAWA  Tetsushi KOIDE  Toru TAMAKI  Shigeto YOSHIDA  Hiroshi MIENO  Shinji TANAKA  

     
    LETTER-VLSI Design Technology and CAD

      Pubricized:
    2021/07/08
      Vol:
    E105-A No:1
      Page(s):
    58-62

    This paper presents examination result of possibility for automatic unclear region detection in the CAD system for colorectal tumor with real time endoscopic video image. We confirmed that it is possible to realize the CAD system with navigation function of clear region which consists of unclear region detection by YOLO2 and classification by AlexNet and SVMs on customizable embedded DSP cores. Moreover, we confirmed the real time CAD system can be constructed by a low power ASIC using customizable embedded DSP cores.

1-20hit(516hit)