The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] ions(1385hit)

281-300hit(1385hit)

  • Reconstructing Sequential Patterns without Knowing Image Correspondences

    Saba Batool MIYAN  Jun SATO  

     
    PAPER-Image Recognition, Computer Vision

      Pubricized:
    2015/04/13
      Vol:
    E98-D No:7
      Page(s):
    1343-1352

    In this paper, we propose a method for reconstructing 3D sequential patterns from multiple images without knowing exact image correspondences and without calibrating linear camera sensitivity parameters on intensity. The sequential pattern is defined as a series of colored 3D points. We assume that the series of the points are obtained in multiple images, but the correspondence of individual points is not known among multiple images. For reconstructing sequential patterns, we consider a camera projection model which combines geometric and photometric information of objects. Furthermore, we consider camera projections in the frequency space. By considering the multi-view relationship on the new projection model, we show that the 3D sequential patterns can be reconstructed without knowing exact correspondence of individual image points in the sequential patterns; moreover, the recovered 3D patterns do not suffer from changes in linear camera sensitivity parameters. The efficiency of the proposed method is tested using real images.

  • Effect Analysis of Coding Convention Violations on Readability of Post-Delivered Code

    Taek LEE  Jung-Been LEE  Hoh Peter IN  

     
    PAPER-Software Engineering

      Pubricized:
    2015/04/10
      Vol:
    E98-D No:7
      Page(s):
    1286-1296

    Adherence to coding conventions during the code production stage of software development is essential. Benefits include enabling programmers to quickly understand the context of shared code, communicate with one another in a consistent manner, and easily maintain the source code at low costs. In reality, however, programmers tend to doubt or ignore the degree to which the quality of their code is affected by adherence to these guidelines. This paper addresses research questions such as “Do violations of coding conventions affect the readability of the produced code?”, “What kinds of coding violations reduce code readability?”, and “How much do variable factors such as developer experience, project size, team size, and project maturity influence coding violations?” To respond to these research questions, we explored 210 open-source Java projects with 117 coding conventions from the Sun standard checklist. We believe our findings and the analysis approach used in the paper will encourage programmers and QA managers to develop their own customized and effective coding style guidelines.

  • Development of Wireless Systems for Disaster Recovery Operations Open Access

    Takashi HIROSE  Fusao NUNO  Masashi NAKATSUGAWA  

     
    INVITED PAPER

      Vol:
    E98-C No:7
      Page(s):
    630-635

    This paper presents wireless systems for use in disaster recovery operations. The Great East Japan Earthquake of March 11, 2011 reinforced the importance of communications in, to, and between disaster areas as lifelines. It also revealed that conventional wireless systems used for disaster recovery need to be renovated to cope with technological changes and to provide their services with easier operations. To address this need we have developed new systems, which include a relay wireless system, subscriber wireless systems, business radio systems, and satellite communication systems. They will be chosen and used depending on the situations in disaster areas as well as on the required services.

  • Securely Computing Three-Input Functions with Eight Cards

    Takuya NISHIDA  Yu-ichi HAYASHI  Takaaki MIZUKI  Hideaki SONE  

     
    PAPER

      Vol:
    E98-A No:6
      Page(s):
    1145-1152

    Assume that Alice, Bob, and Carol, each of whom privately holds a one-bit input, want to learn the output of some Boolean function, say the majority function, of their inputs without revealing more of their own secret inputs than necessary. In this paper, we show that such a secure three-input function evaluation can be performed with a deck of real cards; specifically, the three players can learn only the output of the function using eight physical cards — four black and four red cards — with identical backs.

  • Balanced Boolean Functions of σƒ>22n+2n+3(n≥4)

    Yu ZHOU  Lin WANG  Weiqiong WANG  Xiaoni DU  

     
    LETTER-Cryptography and Information Security

      Vol:
    E98-A No:6
      Page(s):
    1313-1319

    The global avalanche characteristics measure the overall avalanche properties of Boolean functions, an n-variable balanced Boolean function of the sum-of-square indicator reaching σƒ=22n+2n+3 is an open problem. In this paper, we prove that there does not exist a balanced Boolean function with σƒ=22n+2n+3 for n≥4, if the hamming weight of one decomposition function belongs to the interval Q*. Some upper bounds on the order of propagation criterion of balanced Boolean functions with n (3≤n≤100) variables are given, if the number of vectors of propagation criterion is equal and less than 7·2n-3-1. Two lower bounds on the sum-of-square indicator for balanced Boolean functions with optimal autocorrelation distribution are obtained. Furthermore, the relationship between the sum-of-squares indicator and nonlinearity of balanced Boolean functions is deduced, the new nonlinearity improves the previously known nonlinearity.

  • On the Probability of Certificate Revocation in Combinatorial Certificate Management Schemes

    Dae Hyun YUM  

     
    LETTER-Information Network

      Pubricized:
    2015/02/18
      Vol:
    E98-D No:5
      Page(s):
    1104-1107

    To enhance the privacy of vehicle owners, combinatorial certificate management schemes assign each certificate to a large enough group of vehicles so that it will be difficult to link a certificate to any particular vehicle. When an innocent vehicle shares a certificate with a misbehaving vehicle and the certificate on the misbehaving vehicle has been revoked, the certificate on the innocent vehicle also becomes invalid and is said to be covered. When a group of misbehaving vehicles collectively share all the certificates assigned to an innocent vehicle and these certificates are revoked, the innocent vehicle is said to be covered. We point out that the previous analysis of the vehicle cover probability is not correct and then provide a new and exact analysis of the vehicle cover probability.

  • Tomlinson-Harashima Precoding with Substream Permutations Based on the Bit Rate Maximization for Single-User MIMO Systems

    Shigenori KINJO  Shuichi OHNO  

     
    PAPER-Communication Theory and Signals

      Vol:
    E98-A No:5
      Page(s):
    1095-1104

    In this paper, we propose a zero-forcing (ZF) Tomlinson-Harashima precoding (THP) with substream permutations based on the bit rate maximization for single-user MIMO (SU-MIMO) systems. We study the effect of substream permutations on the ZF-THP SU-MIMO systems, when the mean squared error (MSE) and the bit rate are adopted for the selection of the permutation matrix as criteria. Based on our analysis, we propose a method to increase the bit rate by substream permutations, and derive QR and Cholesky decomposition-based algorithms which realize the proposed method. Furthermore, to improve the error rate performance, we apply zero transmission to subchannels with low signal-to-noise ratios. Numerical examples are provided to demonstrate the effectiveness of the proposed THP MIMO system.

  • A Camera and LED-Based Medium Access Control Scheme for Wireless LANs

    Ryo NISHIOKA  Takayuki NISHIO  Masahiro MORIKURA  Koji YAMAMOTO  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E98-B No:5
      Page(s):
    917-926

    The IEEE 802.11 wireless LAN (WLAN) is based on carrier sense multiple access with collision avoidance (CSMA/CA) protocol. CSMA/CA uses a backoff mechanism to avoid collisions among stations (STAs). One disadvantage of backoff mechanisms is that STAs must wait for some period of time before transmission, which degrades spectral efficiency. Moreover, a backoff algorithm cannot completely avoid collisions. We have proposed a novel medium access control (MAC) scheme called the visual recognition-based medium access control (VRMAC) scheme, which uses an LED-camera communication technique. STAs send media-access request messages by blinking their LEDs in VRMAC scheme. An access point (AP) receives the messages via its camera, and then allocates transmission opportunities to the STAs by transmitting control frames. Since the transmission rate of the LED-camera communication is lower than WLAN transmission, the delay of access requesting causes and it could decrease the system throughput of the VRMAC system based WLAN. We reveal the effect of the delay for TCP flows and propose enhanced access procedures to eliminate the effect of the delay. Our simulation results demonstrate that VRMAC scheme increases the system throughput in UDP and TCP traffic. Moreover, the scenario-based evaluations reveal that VRMAC scheme also decreases the session delay which is a metric of quality of experience (QoE) for TCP applications.

  • Predictive Control for Performance Improvement of a Feedback Control System Using Cyclostationary Channels

    Cesar CARRIZO  Kentaro KOBAYASHI  Hiraku OKADA  Masaaki KATAYAMA  

     
    PAPER-Communication Theory and Signals

      Vol:
    E98-A No:4
      Page(s):
    1000-1005

    This manuscript presents a simple scheme to improve the performance of a feedback control system that uses power line channels for its feedback loop. The noise and attenuation of power lines, and thus the signal to noise ratio, are known to be cyclostationary. Such cyclic features in the channel allow us to predict virtually error free transmission instants as well as instants of high probability of errors. This paper introduces and evaluates the effectiveness of a packet transmission scheduling that collaborates with a predictive control scheme adapted to this cyclostationary environment. In other words, we explore the cooperation between the physical and application layers of the system in order to achieve an overall optimization. To rate the control quality of the system we evaluate its stability as well as its ability to follow control commands accurately. We compare a scheme of increased packet rate against our proposed scheme which emulates a high packet rate with the use of predictive control. Through this comparison, we verify the effectiveness of the proposed scheme to improve the control quality of the system, even under low signal to noise ratio conditions in the cyclostationary channel.

  • Contextual Max Pooling for Human Action Recognition

    Zhong ZHANG  Shuang LIU  Xing MEI  

     
    LETTER-Image Recognition, Computer Vision

      Pubricized:
    2015/01/19
      Vol:
    E98-D No:4
      Page(s):
    989-993

    The bag-of-words model (BOW) has been extensively adopted by recent human action recognition methods. The pooling operation, which aggregates local descriptor encodings into a single representation, is a key determiner of the performance of the BOW-based methods. However, the spatio-temporal relationship among interest points has rarely been considered in the pooling step, which results in the imprecise representation of human actions. In this paper, we propose a novel pooling strategy named contextual max pooling (CMP) to overcome this limitation. We add a constraint term into the objective function under the framework of max pooling, which forces the weights of interest points to be consistent with their probabilities. In this way, CMP explicitly considers the spatio-temporal contextual relationships among interest points and inherits the positive properties of max pooling. Our method is verified on three challenging datasets (KTH, UCF Sports and UCF Films datasets), and the results demonstrate that our method achieves better results than the state-of-the-art methods in human action recognition.

  • A Scattering Field Expression by Dielectric Gratings Using Circularly Poarized Waves

    Hideaki WAKABAYASHI  Masamitsu ASAI  Jiro YAMAKITA  

     
    BRIEF PAPER-Electromagnetic Theory

      Vol:
    E98-C No:2
      Page(s):
    162-165

    In the scattering problem of dielectric gratings in conical mounting, we have considered and formulated scattering fields using transverse electric (TE) and transverse magnetic (TM) waves. This paper formulates scattering fields by superpositions of right-circularly (RC) and left-circularly (LC) polarized waves through the matrix eigenvalue method.

  • Dynamic Macro-Based Heuristic Planning through Action Relationship Analysis

    Zhuo JIANG  Junhao WEN  Jun ZENG  Yihao ZHANG  Xibin WANG  Sachio HIROKAWA  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2014/10/23
      Vol:
    E98-D No:2
      Page(s):
    363-371

    The success of heuristic search in AI planning largely depends on the design of the heuristic. On the other hand, previous experience contains potential domain information that can assist the planning process. In this context, we have studied dynamic macro-based heuristic planning through action relationship analysis. We present an approach for analyzing the action relationship and design an algorithm that learns macros in solved cases. We then propose a dynamic macro-based heuristic that appropriately reuses the macros rather than immediately assigning them to domains. The above ideas are incorporated into a working planning system called Dynamic Macro-based Fast Forward planner. Finally, we evaluate our method in a series of experiments. Our method effectively optimizes planning since it reduces the result length by an average of 10% relative to the FF, in a time-economic manner. The efficiency is especially improved when invoking an action consumes time.

  • Orientation-Controlled Films of Thiophene/Phenylene Co-Oligomers

    Masashi KOUDA  Ryuji HIRASE  Takeshi YAMAO  Shu HOTTA  Yuji YOSHIDA  

     
    PAPER

      Vol:
    E98-C No:2
      Page(s):
    73-79

    We deposited thin films of thiophene/phenylene co-oligomers (TPCOs) onto poly(tetrafluoroethylene) (PTFE) layers that were friction-transferred on substrates. These films were composed of aligned molecules in such a way that their polarizations of emissions and absorbances were larger along the drawing direction than those perpendicular to that direction. Organic field-effect transistors (OFETs) fabricated with these films indicated large mobilities, when the drawing direction of PTFE was parallel to the channel length direction. The friction-transfer technique forms the TPCO films that indicate the anisotropic optical and electronic properties.

  • Towards Interactive Object-Oriented Programming

    Keehang KWON  Kyunghwan PARK  Mi-Young PARK  

     
    LETTER-Software System

      Vol:
    E98-D No:2
      Page(s):
    437-438

    To represent interactive objects, we propose a choice-disjunctive declaration statement of the form $S add R$ where S, R are the (procedure or field) declaration statements within a class. This statement has the following semantics: request the user to choose one between S and R when an object of this class is created. This statement is useful for representing interactive objects that require interaction with the user.

  • Recommender System Using Implicit Social Information

    Yusheng LI  Meina SONG  Haihong E  

     
    PAPER-Data Engineering, Web Information Systems

      Pubricized:
    2014/10/29
      Vol:
    E98-D No:2
      Page(s):
    346-354

    Social recommendation systems that make use of the user's social information have recently attracted considerable attention. These recommendation approaches partly solve cold-start and data sparsity problems and significantly improve the performance of recommendation systems. The essence of social recommendation methods is to utilize the user's explicit social connections to improve recommendation results. However, this information is not always available in real-world recommender systems. In this paper, a solution to this problem of explicit social information unavailability is proposed. The existing user-item rating matrix is used to compute implicit social information, and then an ISRec (implicit social recommendation algorithm) which integrates this implicit social information and the user-item rating matrix for social recommendation is introduced. Experimental results show that our method performs much better than state-of-the-art approaches; moreover, complexity analysis indicates that our approach can be applied to very large datasets because it scales linearly with respect to the number of observations in the matrices.

  • Behavior Analysis of Video Application Users on Smart Phones Based on State Transition Diagram

    Norihiro FUKUMOTO  Shigehiro ANO  Shigeki GOTO  

     
    PAPER

      Vol:
    E98-B No:1
      Page(s):
    42-50

    Video traffic occupies a major part of current mobile traffic. The characteristics of video traffic are dominated by the behavior of the video application users. This paper uses a state transition diagram to analyze the behavior of video application users on smart phones. Video application users are divided into two categories; keyword search users and initial screen users. They take different first action in video viewing. The result of our analysis shows that the patience of video application users depends on whether they have a specific purpose when they launch a video application or not. Mobile network operators can improve the QoE of video application users by utilizing the results of this study.

  • Theoretical Limitation of the Radiation Efficiency for Homogenous Electrically Small Antennas

    Keisuke FUJITA  Hiroshi SHIRAI  

     
    PAPER

      Vol:
    E98-C No:1
      Page(s):
    2-7

    Maximum radiation efficiency has been derived for homogeneous electrically small antennas. The spherical wave expansion is utilized to express the radiated field and the current distribution on an antenna, and the radiation efficiency is represented by the current, which is expressed in the spherical wave expansion coefficients and the nonradiating current. By using a concept of the nonradiating current, it is shown that the maximum radiation efficiency is achieved if the antenna shape is spherical. The radiation efficiency of a spherical antenna is maximized by varying the expansion coefficients. This radiation efficiency is compared with that of the antenna which achieves the maximum gain and those of linear antennas. The comparison indicates the validity of our proposed upper limit of the radiation efficiency.

  • Upper Bounds for the Security of Several Feistel Networks

    Yosuke TODO  

     
    PAPER-Symmetric Key Based Cryptography

      Vol:
    E98-A No:1
      Page(s):
    39-48

    In this paper, we deal with upper bounds for the security of some Feistel networks. Such a topic has been discussed since the introduction of Luby-Rackoff construction. The Luby-Rackoff construction is unrealistic because its round functions must be chosen at random from the set of all functions. Knudsen dealt with a more practical construction whose round functions are chosen at random from a family of 2k randomly chosen functions, and showed an upper bound for the security by demonstrating generic key recovery attacks. However it is still difficult for designers to choose functions randomly. Then, this paper considers the security of some Feistel networks which have more efficient and practical round functions, and such Feistel networks are indeed used by some Feistel ciphers in practice. We show new properties using the relationship between plaintexts and ciphertexts. We propose new generic key recovery attacks by using our properties, and confirm the feasibility by implementing the attack on Feistel ciphers with small block sizes. As a result, we conclude that efficient and practical 6-round Feistel networks are not secure.

  • Software-Defined Data Plane Enhancing SDN and NFV Open Access

    Akihiro NAKAO  

     
    INVITED PAPER

      Vol:
    E98-B No:1
      Page(s):
    12-19

    In this paper, we posit that extension of SDN to support deeply and flexibly programmable, software-defined data plane significantly enhance SDN and NFV and their interaction in terms of (1) enhanced interaction between applications and networks, (2) optimization of network functions, and (3) rapid development of new network protocols. All of these benefits are expected to contribute to improving the quality of diversifying communication networks and services. We identify three major technical challenges for enabling software-defined data plane as (1) ease of programming, (2) reasonable and predictable performance and (3) isolation among multiple concurrent logics. We also promote application-driving thinking towards defining software defined data-plane. We briefly introduce our project FLARE and its related technologies and review four use cases of flexible and deeply programmable data plane.

  • Revocable Group Signatures with Compact Revocation List Using Accumulators

    Toru NAKANISHI  Nobuo FUNABIKI  

     
    PAPER-Public Key Based Cryptography

      Vol:
    E98-A No:1
      Page(s):
    117-131

    A group signature scheme allows a group member to anonymously sign a message on behalf of the group. One of the important issues is the member revocation, and lots of revocable schemes have been proposed so far. A scheme recently proposed by Libert et al. achieves that O(1) or O(log N) efficiency of communication and computation except for the revocation list size (also the revocation cost), for the total number of members N and the number of revoked members R. However, since a signature is required for each subset separated from the set of non-revoked members, the size is about 900R Bytes in the 128-bit security. In the case of R=100,000, it amounts to about 80MB. In this paper, we extend the scheme to reduce the revocation list (also the revocation cost), by accumulating T subsets, which is signed for the revocation list. The revocation list size is reduced by 1/T. Unfortunately, the public key size, membership certificate size and the cost of a witness computation needed for signing increase related to T.

281-300hit(1385hit)