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[Keyword] pair(303hit)

101-120hit(303hit)

  • FPGA Implementation of Various Elliptic Curve Pairings over Odd Characteristic Field with Non Supersingular Curves

    Yasuyuki NOGAMI  Hiroto KAGOTANI  Kengo IOKIBE  Hiroyuki MIYATAKE  Takashi NARITA  

     
    PAPER-Cryptography and cryptographic protocols

      Pubricized:
    2016/01/13
      Vol:
    E99-D No:4
      Page(s):
    805-815

    Pairing-based cryptography has realized a lot of innovative cryptographic applications such as attribute-based cryptography and semi homomorphic encryption. Pairing is a bilinear map constructed on a torsion group structure that is defined on a special class of elliptic curves, namely pairing-friendly curve. Pairing-friendly curves are roughly classified into supersingular and non supersingular curves. In these years, non supersingular pairing-friendly curves have been focused on from a security reason. Although non supersingular pairing-friendly curves have an ability to bridge various security levels with various parameter settings, most of software and hardware implementations tightly restrict them to achieve calculation efficiencies and avoid implementation difficulties. This paper shows an FPGA implementation that supports various parameter settings of pairings on non supersingular pairing-friendly curves for which Montgomery reduction, cyclic vector multiplication algorithm, projective coordinates, and Tate pairing have been combinatorially applied. Then, some experimental results with resource usages are shown.

  • New Families of Binary Sequence Pairs with Three-Level Correlation and Odd Composite Length

    Xiuping PENG  Jiadong REN  Chengqian XU  Kai LIU  

     
    LETTER-Spread Spectrum Technologies and Applications

      Vol:
    E99-A No:4
      Page(s):
    874-879

    In this letter, several new families of binary sequence pairs with period N=np, where p is a prime and gcd(n,p)=1, and optimal correlation values 1 and -3 are constructed. These classes of binary sequence pairs are based on Chinese remainder theorem. The constructed sequence pairs have optimum balance among 0's and 1's.

  • Two-Way Cognitive DF Relaying in WSNs with Practical RF Energy Harvesting Node

    Dang Khoa NGUYEN  Hiroshi OCHI  

     
    PAPER-Network

      Vol:
    E99-B No:3
      Page(s):
    675-684

    This work presents the exact outage performance and throughput of two-way cognitive decode-and-forward relaying wireless sensor networks with realistic transceiver relay. The relay is a self-powered wireless node that harvests radio frequency energy from the transmitted signals. We consider four configurations of a network with formed by combining two bidirectional relaying protocols (multiple access broadcast protocol and time division broadcast protocol), and two power transfer policies (dual-source energy transfer and single-fixed-source energy transfer). Based on our analysis, we provide practical insights into the impact of transceiver hardware impairments on the network performance, such as the fundamental capacity ceiling of the network with various configurations that cannot be exceeded by increasing transmit power given a fixed transmission rate and the transceiver selection strategy for the network nodes that can optimize the implementation cost and performance tradeoff.

  • Cooperative Local Repair with Multiple Erasure Tolerance

    Jiyong LU  Xuan GUANG  Linzhi SHEN  Fang-Wei FU  

     
    LETTER-Coding Theory

      Vol:
    E99-A No:3
      Page(s):
    765-769

    In distributed storage systems, codes with lower repair locality are much more desirable due to their superiority in reducing the disk I/O complexity of each repair process. Motivated partially by both codes with information (r,δ1)c locality and codes with cooperative (r,l) locality, we propose the concept of codes with information (r,l,δ) locality in this paper. For a linear code C with information (r,l,δ) locality, values at arbitrary l information coordinates of an information set I can be recovered by connecting any of δ existing pairwise disjoint local repair sets with size no more than r, where a local repair set of l coordinates is defined as the set of some other coordinates by which one can recover the values at these l coordinates. We derive a lower bound on the codeword length n for [n,k,d] linear codes with information (r,l,δ) locality. Furthermore, we indicate its tightness for some special cases. Particularly, some existing results can be deduced from our bound by restriction on parameters.

  • Analysis of Elderly Drivers' Performance Using Large-Scale Test Data

    Yasuhiko NAKANO  Haruki KAWANAKA  Koji OGURI  

     
    PAPER

      Vol:
    E99-A No:1
      Page(s):
    243-251

    This study explored the question of how to minimize older drivers' accidents and to identify at-risk drivers by analyzing their driving performance. Previous traffic research reported that there were two factors involved in risky driving, namely driving risk perception and risky driving attitude. We investigated these two factors as indicators of an at-risk driver by using large-scale test data from license renewal tests that are obligatory for Japanese drivers who are 70 years of age or older. The tests include a driving simulator test, an on-road test, and a cognitive screening test. By using these assessments and predictions made with renewal driving tests, we were able to indicate the possibility of identifying at-risk drivers.

  • A Decoding Algorithm for Cyclic Codes over Symbol-Pair Read Channels

    Makoto TAKITA  Masanori HIROTOMO  Masakatu MORII  

     
    PAPER-Coding Theory

      Vol:
    E98-A No:12
      Page(s):
    2415-2422

    Cassuto and Blaum presented a new coding framework for channels whose outputs are overlapping pairs of symbols in storage applications. Such channels are called symbol-pair read channels. Pair distance and pair error are used in symbol-pair read channels. Yaakobi et al. proved a lower bound on the minimum pair distance of cyclic codes. Furthermore, they provided a decoding algorithm for correcting pair errors using a decoder for cyclic codes, and showed the number of pair errors that can be corrected by their algorithm. However, their algorithm cannot correct all pair error vectors within half of the minimum pair distance. In this paper, we propose an efficient decoding algorithm for cyclic codes over symbol-pair read channels. It is based on the relationship between pair errors and syndromes. In addition, we show that the proposed algorithm can correct more pair errors than Yaakobi's algorithm.

  • An AM-PM Noise Mitigation Technique in Class-C VCO

    Kento KIMURA  Aravind THARAYIL NARAYANAN  Kenichi OKADA  Akira MATSUZAWA  

     
    PAPER-Electronic Circuits

      Vol:
    E98-C No:12
      Page(s):
    1161-1170

    This paper presents a 20GHz Class-C VCO using a noise sensitivity mitigation technique. A radio frequency Class-C VCO suffers from the AM-PM conversion, caused by the non-linear capacitance of cross coupled pair. In this paper, the phase noise degradation mechanism is discussed, and a desensitization technique of AM-PM noise is proposed. In the proposed technique, AM-PM sensitivity is canceled by tuning the tail impedance, which consists of 4-bit resistor switches. A 65-nm CMOS prototype of the proposed VCO demonstrates the oscillation frequency from 19.27 to 22.4GHz, and the phase noise of -105.7dBc/Hz at 1-MHz offset with the power dissipation of 6.84mW, which is equivalent to a Figure-of-Merit of -183.73dBc/Hz.

  • Syndrome Decoding of Symbol-Pair Codes

    Makoto TAKITA  Masanori HIROTOMO  Masakatu MORII  

     
    PAPER-Coding Theory

      Vol:
    E98-A No:12
      Page(s):
    2423-2428

    Cassuto and Blaum proposed new error correcting codes which are called symbol-pair codes. They presented a coding framework for channels whose outputs are overlapping pairs of symbols in storage applications. Such channels are called symbol-pair read channels. The pair distance and pair error are used in symbol-pair read channels. Cassuto et al. and Yaakobi et al. presented decoding algorithms for symbol-pair codes. However, their decoding algorithms cannot always correct errors whose number is not more than half the minimum pair distance. In this paper, we propose a new decoding algorithm using syndromes of symbol-pair codes. In addition, we show that the proposed algorithm can correct all pair errors within the pair error correcting capability.

  • A Length Matching Routing Algorithm for Set-Pair Routing Problem

    Yuta NAKATANI  Atsushi TAKAHASHI  

     
    PAPER-Physical Level Design

      Vol:
    E98-A No:12
      Page(s):
    2565-2571

    In the routing design of interposer and etc., the combination of a pin pair to be connected by wire is often flexible, and the reductions of the total wire length and the length difference are pursued to keep the circuit performance. Even though the total wire length can be minimized by finding a minimum cost maximum flow in set pair routing problems, the length difference is often large, and the reduction of it is not easy. In this paper, an algorithm that reduces the length difference while keeping the total wire length small is proposed. In the proposed algorithm, an initial routing first obtained by a minimum cost maximum flow. Then it is modified to reduce the maximum length while keeping the minimum total wire length, and a connection of the minimum length is detoured to reduce the length difference. The effectiveness of the proposed algorithm is confirmed by experiments.

  • Fast Repairing from Large-Scale Failure Using Hierarchical SDN Controllers

    Shohei KAMAMURA  Hiroshi YAMAMOTO  Kouichi GENDA  Yuki KOIZUMI  Shin'ichi ARAKAWA  Masayuki MURATA  

     
    PAPER-Network

      Vol:
    E98-B No:11
      Page(s):
    2269-2279

    This paper proposes fast repairing methods that uses hierarchical software defined network controllers for recovering from massive failure in a large-scale IP over a wavelength-division multiplexing network. The network consists of multiple domains, and slave controllers are deployed in each domain. While each slave controller configures transport paths in its domain, the master controller manages end-to-end paths, which are established across multiple domains. For fast repair of intra-domain paths by the slave controllers, we define the optimization problem of path configuration order and propose a heuristic method, which minimizes the repair time to move from a disrupted state to a suboptimal state. For fast repair of end-to-end path through multiple domains, we also propose a network abstraction method, which efficiently manages the entire network. Evaluation results suggest that fast repair within a few minutes can be achieved by applying the proposed methods to the repairing scenario, where multiple links and nodes fail, in a 10,000-node network.

  • Optimal Maintenance Policy of a Multi-Unit One-Shot System with Minimal Repair

    Tomohiro KITAGAWA  Tetsushi YUGE  Shigeru YANAGI  

     
    PAPER

      Vol:
    E98-A No:10
      Page(s):
    2077-2083

    A one-shot system is a system that can be used only once during its life, and whose failures are detected only through inspections. In this paper, we discuss an inspection policy problem of one-shot system composed of multi-unit in series. Failed units are minimally repaired when failures are detected and all units in the system are replaced when the nth failure is detected after the last replacement. We derive the expected cost rate approximately. Our goal is to determine the optimal inspection policy that minimizes the expected cost rate.

  • 3D CG Image Quality Metrics by Regions with 8 Viewpoints Parallax Barrier Method

    Norifumi KAWABATA  Masaru MIYAO  

     
    PAPER

      Vol:
    E98-A No:8
      Page(s):
    1696-1708

    Many previous studies on image quality assessment of 3D still images or video clips have been conducted. In particular, it is important to know the region in which assessors are interested or on which they focus in images or video clips, as represented by the ROI (Region of Interest). For multi-view 3D images, it is obvious that there are a number of viewpoints; however, it is not clear whether assessors focus on objects or background regions. It is also not clear on what assessors focus depending on whether the background region is colored or gray scale. Furthermore, while case studies on coded degradation in 2D or binocular stereoscopic videos have been conducted, no such case studies on multi-view 3D videos exist, and therefore, no results are available for coded degradation according to the object or background region in multi-view 3D images. In addition, in the case where the background region is gray scale or not, it was not revealed that there were affection for gaze point environment of assessors and subjective image quality. In this study, we conducted experiments on the subjective evaluation of the assessor in the case of coded degradation by JPEG coding of the background or object or both in 3D CG images using an eight viewpoint parallax barrier method. Then, we analyzed the results statistically and classified the evaluation scores using an SVM.

  • Advantages and Drawbacks of Smartphones and Tablets for Visually Impaired People —— Analysis of ICT User Survey Results ——

    Tetsuya WATANABE  Toshimitsu YAMAGUCHI  Kazunori MINATANI  

     
    PAPER-Rehabilitation Engineering and Assistive Technology

      Pubricized:
    2014/12/26
      Vol:
    E98-D No:4
      Page(s):
    922-929

    A survey was conducted on the use of ICT by visually impaired people. Among 304 respondents, 81 used smartphones and 44, tablets. Blind people used feature phones at a higher rate and smartphones and tablets at lower rates than people with low vision. The most popular smartphone model was iPhone and the most popular tablet model was iPad. While almost all blind users used the speech output accessibility feature and only a few of them used visual features, low vision users used both visual features such as Zoom, Large text, and Invert colors and speech output at high rates both on smartphones and tablets. The most popular text entry methods were different between smartphones and tablets. For smartphones flick and numeric keypad input were popular among low vision users while voice input was the most popular among blind users. For tablets a software QWERTY keyboard was the most popular among both blind and low vision users. The advantages of smartphones were access to geographical information, quick Web browsing, voice input, and extensibility for both blind and low vision users, object recognition for blind users, and readability for low vision users. Tablets also work as a vision aid for people with low vision. The drawbacks of smartphones and tablets were text entry and touch operation difficulties and inaccessible apps for both blind and low vision users, problems in speech output for blind users, and problems in readability for low vision users. Researchers and makers of operating systems (OS) and apps should assume responsibility for solving these problems.

  • Fault Localization Using Failure-Related Contexts for Automatic Program Repair

    Ang LI  Xiaoguang MAO  Yan LEI  Tao JI  

     
    LETTER-Software Engineering

      Pubricized:
    2015/01/08
      Vol:
    E98-D No:4
      Page(s):
    955-959

    Fault localization is essential for conducting effective program repair. However, preliminary studies have shown that existing fault localization approaches do not take the requirements of automatic repair into account, and therefore restrict the repair performance. To address this issue, this paper presents the first study on designing fault localization approaches for automatic program repair, that is, we propose a fault localization approach using failure-related contexts in order to improve automatic program repair. The proposed approach first utilizes program slicing technique to construct a failure-related context, then evaluates the suspiciousness of each element in this context, and finally transfers the result of evaluation to automatic program repair techniques for performing repair on faulty programs. The experimental results demonstrate that the proposed approach is effective to improve automatic repair performance.

  • Two-Step Pairing Algorithm for Target Range and Velocity Detection in FMCW Automotive Radar

    Eugin HYUN  Woojin OH  Jong-Hun LEE  

     
    PAPER-Digital Signal Processing

      Vol:
    E98-A No:3
      Page(s):
    801-810

    In automotive frequency modulated continuous wave (FMCW) radar based on multiple ramps with different slope, an effective pairing algorithm is required to simultaneously detect the target range and velocity. That is, as finding beat-frequencies intersecting at a single point of the range-Doppler map, we extract the range and velocity of a target. Unlike the ideal case, however, in a real radar system, even though multiple beat frequencies are originated from the same target, these beat frequencies have many different intersection values, resulting in mismatch pairing during the pairing step. Moreover, this problem also reduces the detection accuracy and the radar detection performance. In this study, we found that mismatch pairing is caused by the round-off errors of the range-beat frequency and Doppler frequency, as well as their various combinations in the discrete frequency domain. We also investigated the effect of mismatch pairing on detection performance, and proposed a new approach to minimize this problem. First, we propose integer and half-integer frequency position-based pairing method during extraction of the range and Doppler frequencies in each ramp to increase detection accuracy. Second, we propose a window-based pairing method to identify the same target from range-Doppler frequencies extracted in the first step. We also find the appropriate window size to overcome pairing mismatch. Finally, we propose the method to obtain a higher accuracy of range and velocity by weighting the values determined in one window. To verify the detection performance of the proposed method by comparison with the typical method, simulations were conducted. Then, in a real field test using the developed radar prototype, the detection probability of the proposed algorithm showed more than 60% improvement in comparison with the conventional method.

  • Dual Pairing Vector Spaces and Their Applications

    Tatsuaki OKAMOTO  Katsuyuki TAKASHIMA  

     
    INVITED PAPER

      Vol:
    E98-A No:1
      Page(s):
    3-15

    The concept of dual pairing vector spaces (DPVS) was introduced by Okamoto and Takashima in 2009, and it has been employed in various applications, functional encryption (FE) including attribute-based encryption (ABE) and inner-product encryption (IPE) as well as attribute-based signatures (ABS), generic conversion from composite-order group based schemes to prime-order group based ones and public-key watermarking. In this paper, we show the concept of DPVS, the major applications to FE and the key techniques employed in these applications. This paper presents them with placing more emphasis on plain and intuitive descriptions than formal preciseness.

  • An Anonymous Reputation System with Reputation Secrecy for Manager

    Toru NAKANISHI  Nobuo FUNABIKI  

     
    PAPER-Cryptography and Information Security

      Vol:
    E97-A No:12
      Page(s):
    2325-2335

    In anonymous reputation systems, where after an interaction between anonymous users, one of the users evaluates the peer by giving a rating. Ratings for a user are accumulated, which becomes the reputation of the user. By using the reputation, we can know the reliability of an anonymous user. Previously, anonymous reputation systems have been proposed, using an anonymous e-cash scheme. However, in the e-cash-based systems, the bank grasps the accumulated reputations for all users, and the fluctuation of reputations. These are private information for users. Furthermore, the timing attack using the deposit times is possible, which makes the anonymity weak. In this paper, we propose an anonymous reputation system, where the reputations of users are secret for even the reputation manager such as the bank. Our approach is to adopt an anonymous credential certifying the accumulated reputation of a user. Initially a user registers with the reputation manager, and is issued an initial certificate. After each interaction with a rater, the user as the ratee obtains an updated certificate certifying the previous reputation summed up by the current rating. The update protocol is based on the zero-knowledge proofs, and thus the reputations are secret for the reputation manager. On the other hand, due to the certificate, the user cannot maliciously alter his reputation.

  • Optimally Joint Subcarrier Pairing and Power Allocation for OFDM System with Multihop Symbol Level DF Relaying

    Ning WANG  Tingting MIAO  Hongwen YANG  

     
    PAPER-Terrestrial Wireless Communication/Broadcasting Technologies

      Vol:
    E97-B No:12
      Page(s):
    2800-2808

    Subcarrier pairing (SP) and power allocation (PA) can improve the channel capacity of the OFDM multi-hop relay system. Due to limitations of processing complexity and energy consumption, symbol-level relaying, which only regenerates the constellation symbols at relay nodes, is more practical than code-level relaying that requires full decoding and encoding. By modeling multi-hop symbol-level relaying as a multi-staged parallel binary symmetric channel, this paper introduces a jointly optimal SP and PA scheme which maximizes the end to end data rate. Analytical arguments are given to reveal the structures and properties of the optimal solution, and simulation results are presented to illustrate and justify the optimality.

  • Reusing EPR Pairs for Change of Receiver in Quantum Repeater

    Kenichiro FURUTA  

     
    LETTER-General Fundamentals and Boundaries

      Vol:
    E97-A No:11
      Page(s):
    2283-2286

    We focus on a characteristic which is specific to the quantum repeater protocol. In the quantum repeater protocol, quantum states which are generated by the protocol do not depend on receivers. Therefore, we can reuse EPR pairs which are generated before a change of a receiver for the quantum repeater protocol after the change. The purpose of reusing is advancing the finishing time of sharing EPR pairs, which is not equal to increasing the fidelity. In this paper, we construct concrete methods of reusing EPR pairs and analyze the effectiveness of reusing EPR pairs. Besides, we derive conditions in which reusing EPR pairs is effective.

  • Efficient Algorithm for Tate Pairing of Composite Order

    Yutaro KIYOMURA  Tsuyoshi TAKAGI  

     
    PAPER-Cryptography and Information Security

      Vol:
    E97-A No:10
      Page(s):
    2055-2063

    Boneh et al. proposed the new idea of pairing-based cryptography by using the composite order group instead of prime order group. Recently, many cryptographic schemes using pairings of composite order group were proposed. Miller's algorithm is used to compute pairings, and the time of computing the pairings depends on the cost of calculating the Miller loop. As a method of speeding up calculations of the pairings of prime order, the number of iterations of the Miller loop can be reduced by choosing a prime order of low Hamming weight. However, it is difficult to choose a particular composite order that can speed up the pairings of composite order. Kobayashi et al. proposed an efficient algorithm for computing Miller's algorithm by using a window method, called Window Miller's algorithm. We can compute scalar multiplication of points on elliptic curves by using a window hybrid binary-ternary form (w-HBTF). In this paper, we propose a Miller's algorithm that uses w-HBTF to compute Tate pairing efficiently. This algorithm needs a precomputation both of the points on an elliptic curve and rational functions. The proposed algorithm was implemented in Java on a PC and compared with Window Miller's Algorithm in terms of the time and memory needed to make their precomputed tables. We used the supersingular elliptic curve y2=x3+x with embedding degree 2 and a composite order of size of 2048-bit. We denote w as window width. The proposed algorithm with w=6=2·3 was about 12.9% faster than Window Miller's Algorithm with w=2 although the memory size of these algorithms is the same. Moreover, the proposed algorithm with w=162=2·34 was about 12.2% faster than Window Miller's algorithm with w=7.

101-120hit(303hit)