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121-140hit(20498hit)

  • A Sealed-Bid Auction with Fund Binding: Preventing Maximum Bidding Price Leakage Open Access

    Kota CHIN  Keita EMURA  Shingo SATO  Kazumasa OMOTE  

     
    PAPER

      Pubricized:
    2024/02/06
      Vol:
    E107-D No:5
      Page(s):
    615-624

    In an open-bid auction, a bidder can know the budgets of other bidders. Thus, a sealed-bid auction that hides bidding prices is desirable. However, in previous sealed-bid auction protocols, it has been difficult to provide a “fund binding” property, which would guarantee that a bidder has funds more than or equal to the bidding price and that the funds are forcibly withdrawn when the bidder wins. Thus, such protocols are vulnerable to a false bidding. As a solution, many protocols employ a simple deposit method in which each bidder sends a deposit to a smart contract, which is greater than or equal to the bidding price, before the bidding phase. However, this deposit reveals the maximum bidding price, and it is preferable to hide this information. In this paper, we propose a sealed-bid auction protocol that provides a fund binding property. Our protocol not only hides the bidding price and a maximum bidding price, but also provides a fund binding property, simultaneously. For hiding the maximum bidding price, we pay attention to the fact that usual Ethereum transactions and transactions for sending funds to a one-time address have the same transaction structure, and it seems that they are indistinguishable. We discuss how much bidding transactions are hidden. We also employ DECO (Zhang et al., CCS 2020) that proves the validity of the data to a verifier in which the data are taken from a source without showing the data itself. Finally, we give our implementation which shows transaction fees required and compare it to a sealed-bid auction protocol employing the simple deposit method.

  • Locating Concepts on Use Case Steps in Source Code Open Access

    Shinpei HAYASHI  Teppei KATO  Motoshi SAEKI  

     
    PAPER

      Pubricized:
    2023/12/20
      Vol:
    E107-D No:5
      Page(s):
    602-612

    Use case descriptions describe features consisting of multiple concepts with following a procedural flow. Because existing feature location techniques lack a relation between concepts in such features, it is difficult to identify the concepts in the source code with high accuracy. This paper presents a technique to locate concepts in a feature described in a use case description consisting of multiple use case steps using dependency between them. We regard each use case step as a description of a concept and apply an existing concept location technique to the descriptions of concepts and obtain lists of modules. Also, three types of dependencies: time, call, and data dependencies among use case steps are extracted based on their textual description. Modules in the obtained lists failing to match the dependency between concepts are filtered out. Thus, we can obtain more precise lists of modules. We have applied our technique to use case descriptions in a benchmark. Results show that our technique outperformed baseline setting without applying the filtering.

  • Changes in Reading Voice to Convey Design Intention for Users with Visual Impairment Open Access

    Junko SHIROGANE  Daisuke SAYAMA  Hajime IWATA  Yoshiaki FUKAZAWA  

     
    PAPER

      Pubricized:
    2023/12/27
      Vol:
    E107-D No:5
      Page(s):
    589-601

    Webpage texts are often emphasized by decorations such as bold, italic, underline, and text color using HTML (HyperText Markup Language) tags and CSS (Cascading Style Sheets). However, users with visual impairment often struggle to recognize decorations appropriately because most screen readers do not read decorations appropriately. To overcome this limitation, we propose a method to read emphasized texts by changing the reading voice parameters of a screen reader and adding sound effects. First, the strong emphasis types and reading voices are investigated. Second, the intensity of the emphasis type is used to calculate a score. Then the score is used to assign the reading method for the emphasized text. Finally, the proposed method is evaluated by users with and without visual impairment. The proposed method can convey emphasized texts, but future improvements are necessary.

  • A Simplified Method for Determining Mathematical Representation of Microwave Oscillator Load Characteristics Open Access

    Katsumi FUKUMOTO  

     
    BRIEF PAPER-Microwaves, Millimeter-Waves

      Pubricized:
    2023/10/26
      Vol:
    E107-C No:5
      Page(s):
    150-152

    Previously a method was reported to determine the mathematical representation of the microwave oscillator admittance by using numerical calculation. When analyzing the load characteristics and synchronization phenomena by using this formula, the analysis results meet with the experimental results. This paper describes a method to determine the mathematical representation manually.

  • Optical Mode Multiplexer Using LiNbO3 Asymmetric Directional Coupler Enabling Voltage Control for Phase-Matching Condition Open Access

    Shotaro YASUMORI  Seiya MORIKAWA  Takanori SATO  Tadashi KAWAI  Akira ENOKIHARA  Shinya NAKAJIMA  Kouichi AKAHANE  

     
    BRIEF PAPER-Optoelectronics

      Pubricized:
    2023/11/29
      Vol:
    E107-C No:5
      Page(s):
    146-149

    An optical mode multiplexer was newly designed and fabricated using LiNbO3 waveguides. The multiplexer consists of an asymmetric directional coupler capable of achieving the phase-matching condition by the voltage adjustment. The mode conversion efficiency between TM0 and TM1 modes was quantitatively measured to be 0.86 at maximum.

  • Analysis of Optical Power Splitter with Resonator Structure Constructed by Two-Dimensional MDM Plasmonic Waveguide Open Access

    Yoshihiro NAKA  Masahiko NISHIMOTO  Mitsuhiro YOKOTA  

     
    BRIEF PAPER-Electromagnetic Theory

      Pubricized:
    2023/12/07
      Vol:
    E107-C No:5
      Page(s):
    141-145

    An efficient optical power splitter constructed by a metal-dielectric-metal plasmonic waveguide with a resonator structure has been analyzed. The method of solution is the finite difference time domain (FD-TD) method with the piecewise linear recursive convolution (PLRC) method. The resonator structure consists of input/output waveguides and a narrow waveguide with a T-junction. The power splitter with the resonator structure is expressed by an equivalent transmission-line circuit. We can find that the transmittance and reflectance calculated by the FD-TD method and the equivalent circuit are matched when the difference in width between the input/output waveguides and the narrow waveguide is small. It is also shown that the transmission wavelength can be adjusted by changing the narrow waveguide lengths that satisfy the impedance matching condition in the equivalent circuit.

  • An Extension of Physical Optics Approximation for Dielectric Wedge Diffraction for a TM-Polarized Plane Wave Open Access

    Duc Minh NGUYEN  Hiroshi SHIRAI  Se-Yun KIM  

     
    PAPER-Electromagnetic Theory

      Pubricized:
    2023/11/08
      Vol:
    E107-C No:5
      Page(s):
    115-123

    In this study, the edge diffraction of a TM-polarized electromagnetic plane wave by two-dimensional dielectric wedges has been analyzed. An asymptotic solution for the radiation field has been derived from equivalent electric and magnetic currents which can be determined by the geometrical optics (GO) rays. This method may be regarded as an extended version of physical optics (PO). The diffracted field has been represented in terms of cotangent functions whose singularity behaviors are closely related to GO shadow boundaries. Numerical calculations are performed to compare the results with those by other reference solutions, such as the hidden rays of diffraction (HRD) and a numerical finite-difference time-domain (FDTD) simulation. Comparisons of the diffraction effect among these results have been made to propose additional lateral waves in the denser media.

  • The Channel Modeling of Ultra-Massive MIMO Terahertz-Band Communications in the Presence of Mutual Coupling Open Access

    Shouqi LI  Aihuang GUO  

     
    LETTER-Communication Theory and Signals

      Pubricized:
    2023/08/23
      Vol:
    E107-A No:5
      Page(s):
    850-854

    The very high path loss caused by molecular absorption becomes the biggest problem in Terahertz (THz) wireless communications. Recently, the multi-band ultra-massive multi-input multi-output (UM-MIMO) system has been proposed to overcome the distance problem. In UM-MIMO systems, the impact of mutual coupling among antennas on the system performance is unable to be ignored because of the dense array. In this letter, a channel model of UM-MIMO communication system is developed which considers coupling effect. The effect of mutual coupling in the subarray on the functionality of the system has been investigated through simulation studies, and reliable results have been derived.

  • DNN Aided Joint Source-Channel Decoding Scheme for Polar Codes Open Access

    Qingping YU  You ZHANG  Zhiping SHI  Xingwang LI  Longye WANG  Ming ZENG  

     
    LETTER-Coding Theory

      Pubricized:
    2023/08/23
      Vol:
    E107-A No:5
      Page(s):
    845-849

    In this letter, a deep neural network (DNN) aided joint source-channel (JSCC) decoding scheme is proposed for polar codes. In the proposed scheme, an integrated factor graph with an unfolded structure is first designed. Then a DNN aided flooding belief propagation decoding (FBP) algorithm is proposed based on the integrated factor, in which both source and channel scaling parameters in the BP decoding are optimized for better performance. Experimental results show that, with the proposed DNN aided FBP decoder, the polar coded JSCC scheme can have about 2-2.5 dB gain over different source statistics p with source message length NSC = 128 and 0.2-1 dB gain over different source statistics p with source message length NSC = 512 over the polar coded JSCC system with existing BP decoder.

  • A Multiobjective Approach for Side-Channel Based Hardware Trojan Detection Using Power Traces Open Access

    Priyadharshini MOHANRAJ  Saravanan PARAMASIVAM  

     
    PAPER-Cryptography and Information Security

      Pubricized:
    2023/08/23
      Vol:
    E107-A No:5
      Page(s):
    825-835

    The detection of hardware trojans has been extensively studied in the past. In this article, we propose a side-channel analysis technique that uses a wrapper-based feature selection technique for hardware trojan detection. The whale optimization algorithm is modified to carefully extract the best feature subset. The aim of the proposed technique is multiobjective: improve the accuracy and minimize the number of features. The power consumption traces measured from AES-128 trojan circuits are used as features in this experiment. The stabilizing property of the feature selection method helps to bring a mutual trade-off between the precision and recall parameters thereby minimizing the number of false negatives. The proposed hardware trojan detection scheme produces a maximum of 10.3% improvement in accuracy and reduction up to a single feature by employing the modified whale optimization technique. Thus the evaluation results conducted on various trust-hub cryptographic benchmark circuits prove to be efficient from the existing state-of-art methods.

  • Prohibited Item Detection Within X-Ray Security Inspection Images Based on an Improved Cascade Network Open Access

    Qingqi ZHANG  Xiaoan BAO  Ren WU  Mitsuru NAKATA  Qi-Wei GE  

     
    PAPER

      Pubricized:
    2024/01/16
      Vol:
    E107-A No:5
      Page(s):
    813-824

    Automatic detection of prohibited items is vital in helping security staff be more efficient while improving the public safety index. However, prohibited item detection within X-ray security inspection images is limited by various factors, including the imbalance distribution of categories, diversity of prohibited item scales, and overlap between items. In this paper, we propose to leverage the Poisson blending algorithm with the Canny edge operator to alleviate the imbalance distribution of categories maximally in the X-ray images dataset. Based on this, we improve the cascade network to deal with the other two difficulties. To address the prohibited scale diversity problem, we propose the Re-BiFPN feature fusion method, which includes a coordinate attention atrous spatial pyramid pooling (CA-ASPP) module and a recursive connection. The CA-ASPP module can implicitly extract direction-aware and position-aware information from the feature map. The recursive connection feeds the CA-ASPP module processed multi-scale feature map to the bottom-up backbone layer for further multi-scale feature extraction. In addition, a Rep-CIoU loss function is designed to address the overlapping problem in X-ray images. Extensive experimental results demonstrate that our method can successfully identify ten types of prohibited items, such as Knives, Scissors, Pressure, etc. and achieves 83.4% of mAP, which is 3.8% superior to the original cascade network. Moreover, our method outperforms other mainstream methods by a significant margin.

  • Two-Phase Approach to Finding the Most Critical Entities in Interdependent Systems Open Access

    Daichi MINAMIDE  Tatsuhiro TSUCHIYA  

     
    PAPER

      Pubricized:
    2023/09/20
      Vol:
    E107-A No:5
      Page(s):
    786-792

    In interdependent systems, such as electric power systems, entities or components mutually depend on each other. Due to these interdependencies, a small number of initial failures can propagate throughout the system, resulting in catastrophic system failures. This paper addresses the problem of finding the set of entities whose failures will have the worst effects on the system. To this end, a two-phase algorithm is developed. In the first phase, the tight bound on failure propagation steps is computed using a Boolean Satisfiablility (SAT) solver. In the second phase, the problem is formulated as an Integer Linear Programming (ILP) problem using the obtained step bound and solved with an ILP solver. Experimental results show that the algorithm scales to large problem instances and outperforms a single-phase algorithm that uses a loose step bound.

  • A Feedback Vertex Set-Based Approach to Simplifying Probabilistic Boolean Networks Open Access

    Koichi KOBAYASHI  

     
    PAPER

      Pubricized:
    2023/09/26
      Vol:
    E107-A No:5
      Page(s):
    779-785

    A PBN is well known as a mathematical model of complex network systems such as gene regulatory networks. In Boolean networks, interactions between nodes (e.g., genes) are modeled by Boolean functions. In PBNs, Boolean functions are switched probabilistically. In this paper, for a PBN, a simplified representation that is effective in analysis and control is proposed. First, after a polynomial representation of a PBN is briefly explained, a simplified representation is derived. Here, the steady-state value of the expected value of the state is focused, and is characterized by a minimum feedback vertex set of an interaction graph expressing interactions between nodes. Next, using this representation, input selection and stabilization are discussed. Finally, the proposed method is demonstrated by a biological example.

  • Output Feedback Ultimate Boundedness Control with Decentralized Event-Triggering Open Access

    Koichi KITAMURA  Koichi KOBAYASHI  Yuh YAMASHITA  

     
    PAPER

      Pubricized:
    2023/11/10
      Vol:
    E107-A No:5
      Page(s):
    770-778

    In cyber-physical systems (CPSs) that interact between physical and information components, there are many sensors that are connected through a communication network. In such cases, the reduction of communication costs is important. Event-triggered control that the control input is updated only when the measured value is widely changed is well known as one of the control methods of CPSs. In this paper, we propose a design method of output feedback controllers with decentralized event-triggering mechanisms, where the notion of uniformly ultimate boundedness is utilized as a control specification. Using this notion, we can guarantee that the state stays within a certain set containing the origin after a certain time, which depends on the initial state. As a result, the number of times that the event occurs can be decreased. First, the design problem is formulated. Next, this problem is reduced to a BMI (bilinear matrix inequality) optimization problem, which can be solved by solving multiple LMI (linear matrix inequality) optimization problems. Finally, the effectiveness of the proposed method is presented by a numerical example.

  • Distributed Event-Triggered Stochastic Gradient-Tracking for Nonconvex Optimization Open Access

    Daichi ISHIKAWA  Naoki HAYASHI  Shigemasa TAKAI  

     
    PAPER

      Pubricized:
    2024/01/18
      Vol:
    E107-A No:5
      Page(s):
    762-769

    In this paper, we consider a distributed stochastic nonconvex optimization problem for multiagent systems. We propose a distributed stochastic gradient-tracking method with event-triggered communication. A group of agents cooperatively finds a critical point of the sum of local cost functions, which are smooth but not necessarily convex. We show that the proposed algorithm achieves a sublinear convergence rate by appropriately tuning the step size and the trigger threshold. Moreover, we show that agents can effectively solve a nonconvex optimization problem by the proposed event-triggered algorithm with less communication than by the existing time-triggered gradient-tracking algorithm. We confirm the validity of the proposed method by numerical experiments.

  • Extension of Counting LTL and Its Application to a Path Planning Problem for Heterogeneous Multi-Robot Systems Open Access

    Kotaro NAGAE  Toshimitsu USHIO  

     
    INVITED PAPER

      Pubricized:
    2023/10/02
      Vol:
    E107-A No:5
      Page(s):
    752-761

    We address a path planning problem for heterogeneous multi-robot systems under specifications consisting of temporal constraints and routing tasks such as package delivery services. The robots are partitioned into several groups based on their dynamics and specifications. We introduce a concise description of such tasks, called a work, and extend counting LTL to represent such specifications. We convert the problem into an ILP problem. We show that the number of variables in the ILP problem is fewer than that of the existing method using cLTL+. By simulation, we show that the computation time of the proposed method is faster than that of the existing method.

  • Investigation and Improvement on Self-Dithered MASH ΔΣ Modulator for Fractional-N Frequency Synthesis Open Access

    Yuyang ZHU  Zunsong YANG  Masaru OSADA  Haoming ZHANG  Tetsuya IIZUKA  

     
    LETTER

      Pubricized:
    2023/12/05
      Vol:
    E107-A No:5
      Page(s):
    746-750

    Self-dithered digital delta-sigma modulators (DDSMs) are commonly used in fractional-N frequency synthesizers due to their ability to eliminate unwanted spurs from the synthesizer’s spectra without requiring additional hardware. However, when operating with a low-bit input, self-dithered DDSMs can still suffer from spurious tones at certain inputs. In this paper, we propose a self-dithered MASH 1-1-1-1 structure to mitigate the spur issue in the self-dithered MASH DDSMs. The proposed self-dithered MASH 1-1-1-1 suppresses the spurs with shaped dithering and achieves 4th order noise shaping.

  • 150 GHz Fundamental Oscillator Utilizing Transmission-Line-Based Inter-Stage Matching in 130 nm SiGe BiCMOS Technology Open Access

    Sota KANO  Tetsuya IIZUKA  

     
    LETTER

      Pubricized:
    2023/12/05
      Vol:
    E107-A No:5
      Page(s):
    741-745

    A 150 GHz fundamental oscillator employing an inter-stage matching network based on a transmission line is presented in this letter. The proposed oscillator consists of a two-stage common-emitter amplifier loop, whose inter-stage connections are optimized to meet the oscillation condition. The oscillator is designed in a 130-nm SiGe BiCMOS process that offers fT and fMAX of 350 GHz and 450 GHz. According to simulation results, an output power of 3.17 dBm is achieved at 147.6 GHz with phase noise of -115 dBc/Hz at 10 MHz offset and figure-of-merit (FoM) of -180 dBc/Hz.

  • Effects of Parasitic Elements on L-Type LC/CL Matching Circuits Open Access

    Satoshi TANAKA  Takeshi YOSHIDA  Minoru FUJISHIMA  

     
    PAPER

      Pubricized:
    2023/11/07
      Vol:
    E107-A No:5
      Page(s):
    719-726

    L-type LC/CL matching circuits are well known for their simple analytical solutions and have been applied to many radio-frequency (RF) circuits. When actually constructing a circuit, parasitic elements are added to inductors and capacitors. Therefore, each L and C element has a self-resonant frequency, which affects the characteristics of the matching circuit. In this paper, the parallel parasitic capacitance to the inductor and the series parasitic inductor to the capacitance are taken up as parasitic elements, and the details of the effects of the self-resonant frequency of each element on the S11, voltage standing wave ratio (VSWR) and S21 characteristics are reported. When a parasitic element is added, each characteristic basically tends to deteriorate as the self-resonant frequency decreases. However, as an interesting feature, we found that the combination of resonant frequencies determines the VSWR and passband characteristics, regardless of whether it is the inductor or the capacitor.

  • A Mueller-Müller CDR with False-Lock-Aware Locking Scheme for a 56-Gb/s ADC-Based PAM4 Transceiver Open Access

    Fumihiko TACHIBANA  Huy CU NGO  Go URAKAWA  Takashi TOI  Mitsuyuki ASHIDA  Yuta TSUBOUCHI  Mai NOZAWA  Junji WADATSUMI  Hiroyuki KOBAYASHI  Jun DEGUCHI  

     
    PAPER

      Pubricized:
    2023/11/02
      Vol:
    E107-A No:5
      Page(s):
    709-718

    Although baud-rate clock and data recovery (CDR) such as Mueller-Müller (MM) CDR is adopted to ADC-based receivers (RXs), it suffers from false-lock points when the RXs handle PAM4 data pattern because of the absence of edge data. In this paper, a false-lock-aware locking scheme is proposed to address this issue. After the false-lock-aware locking scheme, a clock phase is adjusted to achieve maximum eye height by using a post-1-tap parameter for an FFE in the CDR loop. The proposed techniques are implemented in a 56-Gb/s PAM4 transceiver. A PLL uses an area-efficient “glasses-shaped” inductor. The RX comprises an AFE, a 28-GS/s 7-bit time-interleaved SAR ADC, and a DSP with a 31-tap FFE and a 1-tap DFE. A TX is based on a 7-bit DAC with a 4-tap FFE. The transceiver is fabricated in 16-nm CMOS FinFET technology, and achieves a BER of less than 1e-7 with a 30-dB loss channel. The measurement results show that the MM CDR escapes from false-lock points, and converges to near the optimum point for large eye height.

121-140hit(20498hit)