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  • Authenticated-Encrypted Analog-to-Digital Conversion Based on Non-Linearity and Redundancy Transformation

    Vinod V. GADDE  Makoto IKEDA  

     
    PAPER

      Vol:
    E102-A No:12
      Page(s):
    1731-1740

    We have proposed a generic architecture that can integrate the aspects of confidentiality and integrity into the A/D conversion framework. A conceptual account of the development of the proposed architecture is presented. Using the principle of this architecture we have presented a CMOS circuit design to facilitate a fully integrated Authenticated-Encrypted ADC (AE-ADC). We have implemented and demonstrated a partial 8-bit ADC Analog Front End of this proposed circuit in 0.18µm CMOS with an ENOB of 7.64 bits.

  • Achievable Rate Regions for Source Coding with Delayed Partial Side Information Open Access

    Tetsunao MATSUTA  Tomohiko UYEMATSU  

     
    PAPER-Shannon Theory

      Vol:
    E102-A No:12
      Page(s):
    1631-1641

    In this paper, we consider a source coding with side information partially used at the decoder through a codeword. We assume that there exists a relative delay (or gap) of the correlation between the source sequence and side information. We also assume that the delay is unknown but the maximum of possible delays is known to two encoders and the decoder, where we allow the maximum of delays to change by the block length. In this source coding, we give an inner bound and an outer bound on the achievable rate region, where the achievable rate region is the set of rate pairs of encoders such that the decoding error probability vanishes as the block length tends to infinity. Furthermore, we clarify that the inner bound coincides with the outer bound when the maximum of delays for the block length converges to a constant.

  • Variable-Length Intrinsic Randomness on Two Performance Criteria Based on Variational Distance

    Jun YOSHIZAWA  Shota SAITO  Toshiyasu MATSUSHIMA  

     
    PAPER-Shannon Theory

      Vol:
    E102-A No:12
      Page(s):
    1642-1650

    This paper investigates the problem of variable-length intrinsic randomness for a general source. For this problem, we can consider two performance criteria based on the variational distance: the maximum and average variational distances. For the problem of variable-length intrinsic randomness with the maximum variational distance, we derive a general formula of the average length of uniform random numbers. Further, we derive the upper and lower bounds of the general formula and the formula for a stationary memoryless source. For the problem of variable-length intrinsic randomness with the average variational distance, we also derive a general formula of the average length of uniform random numbers.

  • Distributed Transmission for Secure Wireless Links Based on a Secret-Sharing Method

    Masaaki YAMANAKA  ShenCong WEI  Jingbo ZOU  Shuichi OHNO  Shinichi MIYAMOTO  Seiichi SAMPEI  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2019/06/17
      Vol:
    E102-B No:12
      Page(s):
    2286-2296

    This paper proposes a secure distributed transmission method that establishes multiple transmission routes in space to a destination. In the method, the transmitted information is divided into pieces of information by a secret-sharing method, and the generated pieces are separately transmitted to the destination through different transmission routes using individually-controlled antenna directivities. As the secret-sharing method can divide the transmitted information into pieces in such a manner that nothing about the original information is revealed unless all the divided pieces are obtained, the secrecy of the transmitted information is greatly improved from an information-theoretic basis. However, one problem is that it does not perform well in the vicinity around the receiver. This is due to the characteristics of distributed transmission that all distributed pieces of information must eventually gather at the destination; an eavesdropper can obtain the necessary pieces to reconstruct the original information. Then, this paper expands the distributed transmission method into a two-way communication scheme. By adopting the distributed transmission in both communication directions, a secure link can be provided as a feedback channel to enhance the secrecy of the transmitted information. The generation of the shared pieces of information is given with signal forms, and the secrecy of the proposed method is evaluated based on the signal transmission error rates as determined by computer simulation.

  • Characteristics and Applicability of Frequency Sharing Criteria in the Broadcasting Satellite Link Open Access

    Kazuyoshi SHOGEN  Thong PHAM VIET  

     
    PAPER-Satellite Communications

      Pubricized:
    2019/06/17
      Vol:
    E102-B No:12
      Page(s):
    2297-2303

    Two frequency sharing criteria for BSS (Broadcasting-Satellite Service) are enacted in Sect.1 of Annex 1 to Appendix 30 to Radio Regulations. These two criteria are pfd (power flux-density) and EPM (Equivalent Protection Margin) values. In this paper, the two criteria are compared and studied from the view point of applicability to the sharing cases between BSS and BSS. In particular, it is shown that in some cases, the EPM criterion contributes to alleviate the problem of “sensitive satellite network”, i.e., one that has relatively low transmission power and is very weak against interference and blocks the new satellite to enter. Disclaimer The views and positions expressed by the authors are strictly personal and do not constitute, nor can be interpreted as, the position of the International Telecommunication Union on the topics addressed in this paper.

  • Sparse Time-Varying Complex AR (TV-CAR) Speech Analysis Based on Adaptive LASSO

    Keiichi FUNAKI  

     
    LETTER-Speech and Hearing

      Vol:
    E102-A No:12
      Page(s):
    1910-1914

    Linear Prediction (LP) analysis is commonly used in speech processing. LP is based on Auto-Regressive (AR) model and it estimates the AR model parameter from signals with l2-norm optimization. Recently, sparse estimation is paid attention since it can extract significant features from big data. The sparse estimation is realized by l1 or l0-norm optimization or regularization. Sparse LP analysis methods based on l1-norm optimization have been proposed. Since excitation of speech is not white Gaussian, a sparse LP estimation can estimate more accurate parameter than the conventional l2-norm based LP. These are time-invariant and real-valued analysis. We have been studied Time-Varying Complex AR (TV-CAR) analysis for an analytic signal and have evaluated the performance on speech processing. The TV-CAR methods are l2-norm methods. In this paper, we propose the sparse TV-CAR analysis based on adaptive LASSO (Least absolute shrinkage and selection operator) that is l1-norm regularization and evaluate the performance on F0 estimation of speech using IRAPT (Instantaneous RAPT). The experimental results show that the sparse TV-CAR methods perform better for a high level of additive Pink noise.

  • A Low Area Overhead Design Method for High-Performance General-Synchronous Circuits with Speculative Execution

    Shimpei SATO  Eijiro SASSA  Yuta UKON  Atsushi TAKAHASHI  

     
    PAPER

      Vol:
    E102-A No:12
      Page(s):
    1760-1769

    In order to obtain high-performance circuits in advanced technology nodes, design methodology has to take the existence of large delay variations into account. Clock scheduling and speculative execution have overheads to realize them, but have potential to improve the performance by averaging the imbalance of maximum delay among paths and by utilizing valid data available earlier than worst-case scenarios, respectively. In this paper, we propose a high-performance digital circuit design method with speculative executions with less overhead by utilizing clock scheduling with delay insertions effectively. The necessity of speculations that cause overheads is effectively reduced by clock scheduling with delay insertion. Experiments show that a generated circuit achieves 26% performance improvement with 1.3% area overhead compared to a circuit without clock scheduling and without speculative execution.

  • Representative Spatial Selection and Temporal Combination for 60fps Real-Time 3D Tracking of Twelve Volleyball Players on GPU

    Xina CHENG  Yiming ZHAO  Takeshi IKENAGA  

     
    PAPER-Image

      Vol:
    E102-A No:12
      Page(s):
    1882-1890

    Real-time 3D players tracking plays an important role in sports analysis, especially for the live services of sports broadcasting, which have a strict limitation on processing time. For these kinds of applications, 3D trajectories of players contribute to high-level game analysis such as tactic analysis and commercial applications such as TV contents. Thus real-time implementation for 3D players tracking is expected. In order to achieve real-time for 60fps videos with high accuracy, (that means the processing time should be less than 16.67ms per frame), the factors that limit the processing time of target algorithm include: 1) Large image area of each player. 2) Repeated processing of multiple players in multiple views. 3) Complex calculation of observation algorithm. To deal with the above challenges, this paper proposes a representative spatial selection and temporal combination based real-time implementation for multi-view volleyball players tracking on the GPU device. First, the representative spatial pixel selection, which detects the pixels that mostly represent one image region to scale down the image spatially, reduces the number of processing pixels. Second, the representative temporal likelihood combination shares observation calculation by using the temporal correlation between images so that the times of complex calculation is reduced. The experiments are based on videos of the Final and Semi-Final Game of 2014 Japan Inter High School Games of Men's Volleyball in Tokyo Metropolitan Gymnasium. On the GPU device GeForce GTX 1080Ti, the tracking system achieves real-time on 60fps videos and keeps the tracking accuracy higher than 97%.

  • Acoustic Design Support System of Compact Enclosure for Smartphone Using Deep Neural Network

    Kai NAKAMURA  Kenta IWAI  Yoshinobu KAJIKAWA  

     
    PAPER-Engineering Acoustics

      Vol:
    E102-A No:12
      Page(s):
    1932-1939

    In this paper, we propose an automatic design support system for compact acoustic devices such as microspeakers inside smartphones. The proposed design support system outputs the dimensions of compact acoustic devices with the desired acoustic characteristic. This system uses a deep neural network (DNN) to obtain the relationship between the frequency characteristic of the compact acoustic device and its dimensions. The training data are generated by the acoustic finite-difference time-domain (FDTD) method so that many training data can be easily obtained. We demonstrate the effectiveness of the proposed system through some comparisons between desired and designed frequency characteristics.

  • A Novel Three-Point Windowed Interpolation DFT Method for Frequency Measurement of Real Sinusoid Signal

    Kai WANG  Yiting GAO  Lin ZHOU  

     
    PAPER-Digital Signal Processing

      Vol:
    E102-A No:12
      Page(s):
    1940-1945

    The windowed interpolation DFT methods have been utilized to estimate the parameters of a single frequency and multi-frequency signal. Nevertheless, they do not work well for the real-valued sinusoids with closely spaced positive- and negative- frequency. In this paper, we describe a novel three-point windowed interpolation DFT method for frequency measurement of real-valued sinusoid signal. The exact representation of the windowed DFT with maximum sidelobe decay window (MSDW) is constructed. The spectral superposition of positive- and negative-frequency is considered and calculated to improve the estimation performance. The simulation results match with the theoretical values well. In addition, computer simulations demonstrate that the proposed algorithm provides high estimation accuracy and good noise suppression capability.

  • An Image Fusion Scheme for Single-Shot High Dynamic Range Imaging with Spatially Varying Exposures

    Chihiro GO  Yuma KINOSHITA  Sayaka SHIOTA  Hitoshi KIYA  

     
    PAPER-Image

      Vol:
    E102-A No:12
      Page(s):
    1856-1864

    This paper proposes a novel multi-exposure image fusion (MEF) scheme for single-shot high dynamic range imaging with spatially varying exposures (SVE). Single-shot imaging with SVE enables us not only to produce images without color saturation regions from a single-shot image, but also to avoid ghost artifacts in the producing ones. However, the number of exposures is generally limited to two, and moreover it is difficult to decide the optimum exposure values before the photographing. In the proposed scheme, a scene segmentation method is applied to input multi-exposure images, and then the luminance of the input images is adjusted according to both of the number of scenes and the relationship between exposure values and pixel values. The proposed method with the luminance adjustment allows us to improve the above two issues. In this paper, we focus on dual-ISO imaging as one of single-shot imaging. In an experiment, the proposed scheme is demonstrated to be effective for single-shot high dynamic range imaging with SVE, compared with conventional MEF schemes with exposure compensation.

  • Optimal Balanced Almost 8-QAM Sequences with Three-Level Autocorrelation

    Fanxin ZENG  Xiping HE  Guixin XUAN  Zhenyu ZHANG  Yanni PENG  Linjie QIAN  Li YAN  

     
    LETTER-Sequences

      Vol:
    E102-A No:12
      Page(s):
    1691-1696

    Based on the number of cyclotomy of order eight, a class of balanced almost 8-QAM sequences with odd prime periods is presented. The resultant sequences have low two-level nontrivial autocorrelation values, and their distribution is determined. Furthermore, the smallest possible absolute sidelobes (SPASs) of autocorrelation functions of balanced almost 8-QAM sequences are derived. Compared with the obtained SPASs, some of the proposed sequences is optimal or suboptimal.

  • Hardware-Aware Sum-Product Decoding in the Decision Domain Open Access

    Mizuki YAMADA  Keigo TAKEUCHI  Kiyoyuki KOIKE  

     
    PAPER-Coding Theory

      Vol:
    E102-A No:12
      Page(s):
    1980-1987

    We propose hardware-aware sum-product (SP) decoding for low-density parity-check codes. To simplify an implementation using a fixed-point number representation, we transform SP decoding in the logarithm domain to that in the decision domain. A polynomial approximation is proposed to implement an update rule of the proposed SP decoding efficiently. Numerical simulations show that the approximate SP decoding achieves almost the same performance as the exact SP decoding when an appropriate degree in the polynomial approximation is used, that it improves the convergence properties of SP and normalized min-sum decoding in the high signal-to-noise ratio regime, and that it is robust against quantization errors.

  • Understanding Developer Commenting in Code Reviews

    Toshiki HIRAO  Raula GAIKOVINA KULA  Akinori IHARA  Kenichi MATSUMOTO  

     
    PAPER

      Pubricized:
    2019/09/11
      Vol:
    E102-D No:12
      Page(s):
    2423-2432

    Modern code review is a well-known practice to assess the quality of software where developers discuss the quality in a web-based review tool. However, this lightweight approach may risk an inefficient review participation, especially when comments becomes either excessive (i.e., too many) or underwhelming (i.e., too few). In this study, we investigate the phenomena of reviewer commenting. Through a large-scale empirical analysis of over 1.1 million reviews from five OSS systems, we conduct an exploratory study to investigate the frequency, size, and evolution of reviewer commenting. Moreover, we also conduct a modeling study to understand the most important features that potentially drive reviewer comments. Our results find that (i) the number of comments and the number of words in the comments tend to vary among reviews and across studied systems; (ii) reviewers change their behaviours in commenting over time; and (iii) human experience and patch property aspects impact the number of comments and the number of words in the comments.

  • Reconfigurable 3D Sound Processor and Its Automatic Design Environment Using High-Level Synthesis

    Saya OHIRA  Naoki TSUCHIYA  Tetsuya MATSUMURA  

     
    PAPER

      Vol:
    E102-A No:12
      Page(s):
    1804-1812

    We propose a three-dimensional (3D) sound processor architecture that includes super-directional modulation intellectual property (IP) and 3D sound processing IP and for consumer applications. In addition, we also propose an automatic design environment for 3D sound processing IP. This processor can generate realistic small sound fields in arbitrary spaces using ultrasound. In particular, in the 3D sound processing IP, in order to reproduce 3D audio, it is necessary to reproduce the personal frequency characteristics of complex head related transfer functions. For this reason, we have constructed an automatic design environment with high reconfigurability. This automatic design environment is based on high-level synthesis, and it is possible to automatically generate a C-based algorithm simulator and automatically synthesize the IP hardware by inputting a parameter description file for filter design. This automatic design environment can reduce the design period to approximately 1/5 as compared with conventional manual design. Applying the automatic design environment, a 3D sound processing IP was designed experimentally. The designed IP can be sufficiently applied to consumer applications from the viewpoints of hardware amount and power consumption.

  • Detecting Surface Defects of Wind Tubine Blades Using an Alexnet Deep Learning Algorithm Open Access

    Xiao-Yi ZHAO  Chao-Yi DONG  Peng ZHOU  Mei-Jia ZHU  Jing-Wen REN  Xiao-Yan CHEN  

     
    PAPER-Machine Learning

      Vol:
    E102-A No:12
      Page(s):
    1817-1824

    The paper employed an Alexnet, which is a deep learning framework, to automatically diagnose the damages of wind power generator blade surfaces. The original images of wind power generator blade surfaces were captured by machine visions of a 4-rotor UAV (unmanned aerial vehicle). Firstly, an 8-layer Alexnet, totally including 21 functional sub-layers, is constructed and parameterized. Secondly, the Alexnet was trained with 10000 images and then was tested by 6-turn 350 images. Finally, the statistic of network tests shows that the average accuracy of damage diagnosis by Alexnet is about 99.001%. We also trained and tested a traditional BP (Back Propagation) neural network, which have 20-neuron input layer, 5-neuron hidden layer, and 1-neuron output layer, with the same image data. The average accuracy of damage diagnosis of BP neural network is 19.424% lower than that of Alexnet. The point shows that it is feasible to apply the UAV image acquisition and the deep learning classifier to diagnose the damages of wind turbine blades in service automatically.

  • Security Performance Analysis of Joint Multi-Relay and Jammer Selection for Physical-Layer Security under Nakagami-m Fading Channel

    Guangna ZHANG  Yuanyuan GAO  Huadong LUO  Nan SHA  Mingxi GUO  Kui XU  

     
    LETTER-Cryptography and Information Security

      Vol:
    E102-A No:12
      Page(s):
    2015-2020

    In this paper, we investigate a novel joint multi-relay and jammer selection (JMRJS) scheme in order to improve the physical layer security of wireless networks. In the JMRJS scheme, all the relays succeeding in source decoding are selected to assist in the source signal transmission and meanwhile, all the remaining relay nodes are employed to act as friendly jammers to disturb the eavesdroppers by broadcasting artificial noise. Based on the more general Nakagami-m fading channel, we analyze the security performance of the JMRJS scheme for protecting the source signal against eavesdropping. The exact closed-form expressions of outage probability (OP) and intercept probability (IP) for the JMRJS scheme over Nakagami-m fading channel are derived. Moreover, we analyze the security-reliability tradeoff (SRT) of this scheme. Simulation results show that as the number of decode-and-forward (DF)relay nodes increases, the SRT of the JMRJS scheme improves notably. And when the transmit power is below a certain value, the SRT of the JMRJS scheme consistently outperforms the joint single-relay and jammer selection (JSRJS) scheme and joint equal-relay and jammer selection (JERJS) scheme respectively. In addition, the SRT of this scheme is always better than that of the multi-relay selection (MRS) scheme.

  • New Sub-Band Adaptive Volterra Filter for Identification of Loudspeaker

    Satoshi KINOSHITA  Yoshinobu KAJIKAWA  

     
    PAPER-Digital Signal Processing

      Vol:
    E102-A No:12
      Page(s):
    1946-1955

    Adaptive Volterra filters (AVFs) are usually used to identify nonlinear systems, such as loudspeaker systems, and ordinary adaptive algorithms can be used to update the filter coefficients of AVFs. However, AVFs require huge computational complexity even if the order of the AVF is constrained to the second order. Improving calculation efficiency is therefore an important issue for the real-time implementation of AVFs. In this paper, we propose a novel sub-band AVF with high calculation efficiency for second-order AVFs. The proposed sub-band AVF consists of four parts: input signal transformation for a single sub-band AVF, tap length determination to improve calculation efficiency, switching the number of sub-bands while maintaining the estimation accuracy, and an automatic search for an appropriate number of sub-bands. The proposed sub-band AVF can improve calculation efficiency for which the dominant nonlinear components are concentrated in any frequency band, such as loudspeakers. A simulation result demonstrates that the proposed sub-band AVF can realize higher estimation accuracy than conventional efficient AVFs.

  • User Transition Pattern Analysis for Travel Route Recommendation

    Junjie SUN  Chenyi ZHUANG  Qiang MA  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2019/09/06
      Vol:
    E102-D No:12
      Page(s):
    2472-2484

    A travel route recommendation service that recommends a sequence of points of interest for tourists traveling in an unfamiliar city is a very useful tool in the field of location-based social networks. Although there are many web services and mobile applications that can help tourists to plan their trips by providing information about sightseeing attractions, travel route recommendation services are still not widely applied. One reason could be that most of the previous studies that addressed this task were based on the orienteering problem model, which mainly focuses on the estimation of a user-location relation (for example, a user preference). This assumes that a user receives a reward by visiting a point of interest and the travel route is recommended by maximizing the total rewards from visiting those locations. However, a location-location relation, which we introduce as a transition pattern in this paper, implies useful information such as visiting order and can help to improve the quality of travel route recommendations. To this end, we propose a travel route recommendation method by combining location and transition knowledge, which assigns rewards for both locations and transitions.

  • A Study on the Current Status of Functional Idioms in Java

    Hiroto TANAKA  Shinsuke MATSUMOTO  Shinji KUSUMOTO  

     
    PAPER

      Pubricized:
    2019/09/06
      Vol:
    E102-D No:12
      Page(s):
    2414-2422

    Over the past recent decades, numerous programming languages have expanded to embrace multi-paradigms such as the fusion of object-oriented and functional programming. For example, Java, one of the most famous object-oriented programming languages, introduced a number of functional idioms in 2014. This evolution enables developers to achieve various benefits from both paradigms. However, we do not know how Java developers use functional idioms actually. Additionally, the extent to which, while there are several criticisms against the idioms, the developers actually accept and/or use the idioms currently remains unclear. In this paper, we investigate the actual use status of three functional idioms (Lambda Expression, Stream, and Optional) in Java projects by mining 100 projects containing approximately 130,000 revisions. From the mining results, we determined that Lambda Expression is utilized in 16% of all the examined projects, whereas Stream and Optional are only utilized in 2% to 3% of those projects. It appears that most Java developers avoid using functional idioms just because of keeping compatibility Java versions, while a number of developers accept these idioms for reasons of readability and runtime performance improvements. Besides, when they adopt the idioms, Lambda Expression frequently consists of a single statement, and Stream is used to operate the elements of a collection. On the other hand, some developers implement Optional using deprecated methods. We can say that good usage of the idioms should be widely known among developers.

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