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161-180hit(1376hit)

  • Electro-Optical Characteristics and Curvature Resistance of Dye-Doped Liquid Crystal Gel Films for Stretchable Displays

    Ryosuke SAITO  Yosei SHIBATA  Takahiro ISHINABE  Hideo FUJIKAKE  

     
    BRIEF PAPER

      Vol:
    E101-C No:11
      Page(s):
    901-905

    In this study, we evaluated the electro-optical characteristics and structural stability in curved state of dye-doped liquid crystal (LC) gel film for stretchable displays. As the results, maximum contrast ratio of 6.7:1 and suppression of LC flow were achieved by optimum of blend condition such as gelator and dye concentration.

  • Improvement of Isolation Characteristics of Multi-Way Power Divider Using TE10-TEp0 Mode Transducer

    Mitsuyoshi KISHIHARA  Isao OHTA  

     
    BRIEF PAPER-Microwaves, Millimeter-Waves

      Vol:
    E101-C No:10
      Page(s):
    831-835

    Recently, a multi-way TE10 mode power divider based on the TE10-TEp0 mode transducers consisting of a linearly arranged single-mode waveguide (SMWG) and an over-moded waveguide (OMWG) has been reported. However, the multi-way power divider based on the present mode transducer results in poor isolation and output matching characteristics. In this paper, an improvement of the isolation and the output matching characteristics is attempted by inserting the resistive sheets in the OMWG. It is shown that the isolation characteristics of about 20 dB are achieved by adjusting the dimensions of the resistive sheets. The validity of the design results is confirmed by an experiment.

  • Enumerating Floorplans with Columns

    Katsuhisa YAMANAKA  Md. Saidur RAHMAN  Shin-ichi NAKANO  

     
    PAPER

      Vol:
    E101-A No:9
      Page(s):
    1392-1397

    Given an axis-aligned rectangle R and a set P of n points in the proper inside of R we wish to partition R into a set S of n+1 rectangles so that each point in P is on the common boundary between two rectangles in S. We call such a partition of R a feasible floorplan of R with respect to P. Intuitively, P is the locations of columns and a feasible floorplan is a floorplan in which no column is in the proper inside of a room, i.e., columns are allowed to be placed only on the partition walls between rooms. In this paper we give an efficient algorithm to enumerate all feasible floorplans of R with respect to P. The algorithm is based on the reverse search method, and enumerates all feasible floorplans in O(|SP|) time using O(n) space, where SP is the set of the feasible floorplans of R with respect to P, while the known algorithms need either O(n|SP|) time and O(n) space or O(log n|SP|) time and O(n3) space.

  • Meeting Tight Security for Multisignatures in the Plain Public Key Model

    Naoto YANAI  

     
    PAPER

      Vol:
    E101-A No:9
      Page(s):
    1484-1493

    Multisignatures are digital signatures for a group consisting of multiple signers where each signer signs common documents via interaction with its co-signers and the data size of the resultant signatures for the group is independent of the number of signers. In this work, we propose a multisignature scheme, whose security can be tightly reduced to the CDH problem in bilinear groups, in the strongest security model where nothing more is required than that each signer has a public key, i.e., the plain public key model. Loosely speaking, our main idea for a tight reduction is to utilize a three-round interaction in a full-domain hash construction. Namely, we surmise that a full-domain hash construction with three-round interaction will become tightly secure under the CDH problem. In addition, we show that the existing scheme by Zhou et al. (ISC 2011) can be improved to a construction with a tight security reduction as an application of our proof framework.

  • An Efficient Misalignment Method for Visual Tracking Based on Sparse Representation

    Shan JIANG  Cheng HAN  Xiaoqiang DI  

     
    PAPER-Image Recognition, Computer Vision

      Pubricized:
    2018/05/14
      Vol:
    E101-D No:8
      Page(s):
    2123-2131

    Sparse representation has been widely applied to visual tracking for several years. In the sparse representation framework, tracking problem is transferred into solving an L1 minimization issue. However, during the tracking procedure, the appearance of target was affected by external environment. Therefore, we proposed a robust tracking algorithm based on the traditional sparse representation jointly particle filter framework. First, we obtained the observation image set from particle filter. Furthermore, we introduced a 2D transformation on the observation image set, which enables the tracking target candidates set more robust to handle misalignment problem in complex scene. Moreover, we adopt the occlusion detection mechanism before template updating, reducing the drift problem effectively. Experimental evaluations on five public challenging sequences, which exhibit occlusions, illuminating variations, scale changes, motion blur, and our tracker demonstrate accuracy and robustness in comparisons with the state-of-the-arts.

  • Frequency-Dependent LOD-FDTD Method in Cylindrical Coordinates

    Jun SHIBAYAMA  Tatsuyuki HARA  Masato ITO  Junji YAMAUCHI  Hisamatsu NAKANO  

     
    BRIEF PAPER

      Vol:
    E101-C No:8
      Page(s):
    637-639

    The locally one-dimensional finite-difference time-domain (FDTD) method in cylindrical coordinates is extended to a frequency-dependent version. The fundamental scheme is utilized to perform matrix-operator-free formulations in the right-hand sides. For the analysis of surface plasmon polaritons propagating along a plasmonic grating, the computation time is significantly reduced to less than 10%, compared with the explicit cylindrical FDTD method.

  • An On-The-Fly Jitter Suppression Technique for Plain-CMOS-Logic-Based Timing Verniers: Dynamic Power Compensation with the Extensions of Digitally Variable Delay Lines

    Nobutaro SHIBATA  Mitsuo NAKAMURA  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E101-A No:8
      Page(s):
    1185-1196

    Timing vernier (i.e., digital-to-time converter) is a key component of the pin-electronics circuit board installed in automated digital-VLSI test equipment, and it is used to create fine delays of less than one-cycle time of a clock signal. This paper presents a new on-the-fly (timing-) jitter suppression technique which makes it possible to use low-power plain-CMOS-logic-based timing verniers. Using a power-compensation line installed at the poststage of the digitally variable delay line, we make every pulse (used as a timing signal) consume a fixed amount of electric energy independent of the required delay amount. Since the power load of intrapowerlines is kept constantly, the jitter increase in the situation of changing the required delay amount on the fly is suppressed. On the basis of the concept, a 10-ns span, 125-MHz timing-vernier macro was designed and fabricated with a CMOS process for logic VLSIs. Every macro installed in a real-time timing-signal generator VLSI achieved the required timing resolution of 31.25ps with a linearity error within 15ps. The on-the-fly jitter was successfully suppressed to a random jitter level (<26ps p-p).

  • Energy-Efficient Mobile Video Delivery Utilizing Moving Route Navigation and Video Playout Buffer Control

    Kenji KANAI  Sakiko TAKENAKA  Jiro KATTO  Tutomu MURASE  

     
    PAPER

      Pubricized:
    2018/01/22
      Vol:
    E101-B No:7
      Page(s):
    1635-1644

    Because mobile users demand a high quality and energy-friendly video delivery service that efficiently uses wireless resources, we introduce an energy-efficient video delivery system by applying moving route navigation and playout buffer control based on the mobile throughput history data. The proposed system first determines the optimal travel route to achieve high-speed and energy-efficient communications. Then when a user enters a high throughput area, our system temporarily extends the video playout buffer size, and the user aggressively downloads video segments via a high-speed and energy-efficient wireless connection until the extended buffer is filled. After leaving this area, the user consumes video segments from the extended buffer in order to keep smooth video playback without wireless communications. We carry out computer simulations, laboratory and field experiments and confirm that the proposed system can achieve energy-efficient mobile video delivery.

  • Analysis of a Plasmonic Pole-Absorber Using a Periodic Structure Open Access

    Junji YAMAUCHI  Shintaro OHKI  Yudai NAKAGOMI  Hisamatsu NAKANO  

     
    INVITED PAPER

      Vol:
    E101-C No:7
      Page(s):
    495-500

    A plasmonic black pole (PBP) consisting of a series of touching spherical metal surfaces is analyzed using the finite-difference time-domain (FDTD) method with the periodic boundary condition. First, the wavelength characteristics of the PBP are studied under the assumption that the PBP is omnidirectionally illuminated. It is found that partial truncation of each metal sphere reduces the reflectivity over a wide wavelength range. Next, we consider the case where the PBP is illuminated with a cylindrical wave from a specific direction. It is shown that an absorptivity of more than 80% is obtained over a wavelength range of λ=500 nm to 1000 nm. Calculation regarding the Poynting vector distribution also shows that the incident wave is bent and absorbed towards the center axis of the PBP.

  • Compact CAR: Low-Overhead Cache Replacement Policy for an ICN Router

    Atsushi OOKA  Suyong EUM  Shingo ATA  Masayuki MURATA  

     
    PAPER-Network System

      Pubricized:
    2017/12/18
      Vol:
    E101-B No:6
      Page(s):
    1366-1378

    Information-centric networking (ICN) has gained attention from network research communities due to its capability of efficient content dissemination. In-network caching function in ICN plays an important role to achieve the design motivation. However, many researchers on in-network caching due to its ability to efficiently disseminate content. The in-network caching function in ICN plays an important role in realizing the design goals. However, many in-network caching researchers have focused on where to cache rather than how to cache: the former is known as content deployment in the network and the latter is known as cache replacement in an ICN router. Although the cache replacement has been intensively researched in the context of web-caching and content delivery network previously, networks, the conventional approaches cannot be directly applied to ICN due to the fine granularity of chunks in ICN, which eventually changes the access patterns. In this paper, we argue that ICN requires a novel cache replacement algorithm to fulfill the requirements in the design of a high performance ICN router. Then, we propose a novel cache replacement algorithm to satisfy the requirements named Compact CLOCK with Adaptive Replacement (Compact CAR), which can reduce the consumption of cache memory to one-tenth compared to conventional approaches. In this paper, we argue that ICN requires a novel cache replacement algorithm to fulfill the requirements set for high performance ICN routers. Our solution, Compact CLOCK with Adaptive Replacement (Compact CAR), is a novel cache replacement algorithm that satisfies the requirements. The evaluation result shows that the consumption of cache memory required to achieve a desired performance can be reduced by 90% compared to conventional approaches such as FIFO and CLOCK.

  • Horizontal Partition for Scalable Control in Software-Defined Data Center Networks

    Shaojun ZHANG  Julong LAN  Chao QI  Penghao SUN  

     
    LETTER-Information Network

      Pubricized:
    2018/03/07
      Vol:
    E101-D No:6
      Page(s):
    1691-1693

    Distributed control plane architecture has been employed in software-defined data center networks to improve the scalability of control plane. However, since the flow space is partitioned by assigning switches to different controllers, the network topology is also partitioned and the rule setup process has to invoke multiple controllers. Besides, the control load balancing based on switch migration is heavyweight. In this paper, we propose a lightweight load partition method which decouples the flow space from the network topology. The flow space is partitioned with hosts rather than switches as carriers, which supports fine-grained and lightweight load balancing. Moreover, the switches are no longer needed to be assigned to different controllers and we keep all of them controlled by each controller, thus each flow request can be processed by exactly one controller in a centralized style. Evaluations show that our scheme reduces rule setup costs and achieves lightweight load balancing.

  • Improvement of Endurance Characteristics for Al-Gate Hf-Based MONOS Structures on Atomically Flat Si(100) Surface Realized by Annealing in Ar/H2 Ambient

    Sohya KUDOH  Shun-ichiro OHMI  

     
    PAPER

      Vol:
    E101-C No:5
      Page(s):
    328-333

    In this study, the effect of atomically flat Si(100) surface on Hf-based Metal-Oxide-Nitride-Oxide-Silicon (MONOS) structure was investigated. After the atomically flat Si(100) surface formation by annealing at 1050/60min in Ar/4%H2 ambient, HfO2(O)/HfN1.0(N)/HfO2(O) structure with thickness of 10/3/2nm, respectively, was in-situ deposited by electron cyclotron resonance (ECR) plasma sputtering. The memory window (MW) of Al/HfO2/HfN1.0/HfO2/p-Si(100) diodes was increased from 1.0V to 2.5V by flattening of Si(100) surface. The program and erase (P/E) voltage/time were set as 10V/5s and -8V/5s, respectively. Furthermore, it was found that the gate current density after the 103P/E cycles was decreased one order of magnitude by flattening of Si(100) surface in Ar/4.0%H2 ambient.

  • A Ranking-Based Text Matching Approach for Plagiarism Detection

    Leilei KONG  Zhongyuan HAN  Haoliang QI  Zhimao LU  

     
    PAPER-Information Theory

      Vol:
    E101-A No:5
      Page(s):
    799-810

    This paper addresses the issue of text matching for plagiarism detection. This task aims at identifying the matching plagiarism segments in a pair of suspicious document and its plagiarism source document. All the time, heuristic-based methods are mainly utilized to resolve this problem. But the heuristics rely on the experts' experiences and fail to integrate more features to detect the high obfuscation plagiarism matches. In this paper, a statistical machine learning approach, named the Ranking-based Text Matching Approach for Plagiarism Detection, is proposed to deal with the issues of high obfuscation plagiarism detection. The plagiarism text matching is formalized as a ranking problem, and a pairwise learning to rank algorithm is exploited to identify the most probable plagiarism matches for a given suspicious segment. Especially, the Meteor evaluation metrics of machine translation are subsumed by the proposed method to capture the lexical and semantic text similarity. The proposed method is evaluated on PAN12 and PAN13 text alignment corpus of plagiarism detection and compared to the methods achieved the best performance in PAN12, PAN13 and PAN14. Experimental results demonstrate that the proposed method achieves statistically significantly better performance than the baseline methods in all twelve document collections belonging to five different plagiarism categories. Especially at the PAN12 Artificial-high Obfuscation sub-corpus and PAN13 Summary Obfuscation plagiarism sub-corpus, the main evaluation metrics PlagDet of the proposed method are even 22% and 43% relative improvements than the baselines. Moreover, the efficiency of the proposed method is also better than that of baseline methods.

  • Proposed Hyperbolic NILT Method — Acceleration Techniques and Two-Dimensional Expansion for Electrical Engineering Applications

    Nawfal AL-ZUBAIDI R-SMITH  Lubomír BRANČÍK  

     
    PAPER-Numerical Analysis and Optimization

      Vol:
    E101-A No:5
      Page(s):
    763-771

    Numerical inverse Laplace transform (NILT) methods are potential methods for time domain simulations, for instance the analysis of the transient phenomena in systems with lumped and/or distributed parameters. This paper proposes a numerical inverse Laplace transform method based originally on hyperbolic relations. The method is further enhanced by properly adapting several convergence acceleration techniques, namely, the epsilon algorithm of Wynn, the quotient-difference algorithm of Rutishauser and the Euler transform. The resulting accelerated models are compared as for their accuracy and computational efficiency. Moreover, an expansion to two dimensions is presented for the first time in the context of the accelerated hyperbolic NILT method, followed by the error analysis. The expansion is done by repeated application of one-dimensional partial numerical inverse Laplace transforms. A detailed static error analysis of the resulting 2D NILT is performed to prove the effectivness of the method. The work is followed by a practical application of the 2D NILT method to simulate voltage/current distributions along a transmission line. The method and application are programmed using the Matlab language.

  • Detecting Malware-Infected Devices Using the HTTP Header Patterns

    Sho MIZUNO  Mitsuhiro HATADA  Tatsuya MORI  Shigeki GOTO  

     
    PAPER-Information Network

      Pubricized:
    2018/02/08
      Vol:
    E101-D No:5
      Page(s):
    1370-1379

    Damage caused by malware has become a serious problem. The recent rise in the spread of evasive malware has made it difficult to detect it at the pre-infection timing. Malware detection at post-infection timing is a promising approach that fulfills this gap. Given this background, this work aims to identify likely malware-infected devices from the measurement of Internet traffic. The advantage of the traffic-measurement-based approach is that it enables us to monitor a large number of endhosts. If we find an endhost as a source of malicious traffic, the endhost is likely a malware-infected device. Since the majority of malware today makes use of the web as a means to communicate with the C&C servers that reside on the external network, we leverage information recorded in the HTTP headers to discriminate between malicious and benign traffic. To make our approach scalable and robust, we develop the automatic template generation scheme that drastically reduces the amount of information to be kept while achieving the high accuracy of classification; since it does not make use of any domain knowledge, the approach should be robust against changes of malware. We apply several classifiers, which include machine learning algorithms, to the extracted templates and classify traffic into two categories: malicious and benign. Our extensive experiments demonstrate that our approach discriminates between malicious and benign traffic with up to 97.1% precision while maintaining the false positive rate below 1.0%.

  • Investigative Report Writing Support System for Effective Knowledge Construction from the Web

    Hiroyuki MITSUHARA  Masami SHISHIBORI  Akihiro KASHIHARA  

     
    PAPER-Creativity Support Systems and Decision Support Systems

      Pubricized:
    2018/01/19
      Vol:
    E101-D No:4
      Page(s):
    874-883

    Investigative reports plagiarized from the web should be eliminated because such reports result in ineffective knowledge construction. In this study, we developed an investigative report writing support system for effective knowledge construction from the web. The proposed system attempts to prevent plagiarism by restricting copying and pasting information from web pages. With this system, students can verify information through web browsing, externalize their constructed knowledge as notes for report materials, write reports using these notes, and remove inadequacies in the report by reflection. A comparative experiment showed that the proposed system can potentially prevent web page plagiarism and make knowledge construction from the web more effective compared to a conventional report writing environment.

  • Numerical Analysis of a Tunable Magnetized Plasma Loop Antenna

    Mohammadreza GHADERI  Gholamreza MORADI  

     
    PAPER-Antennas and Propagation

      Pubricized:
    2017/10/06
      Vol:
    E101-B No:4
      Page(s):
    1055-1060

    In this study, a plasma loop tube is presented as a tunable VHF-UHF band plasma antenna. In plasma medium, wave radiation mechanism is due to ionized gas instead of metal. Meanwhile, the most important advantage of plasma elements is electronic tunability rather than the rigid and fixed features of metals. Here, we employ an external magnetic field as a background to affect the plasma without any shape, gas or source manipulation. Finite difference time domain (FDTD) is performed for plasma antenna analysis. The FDTD formulation should be adapted to fluid modeling of plasma in the anisotropic zone in the presence of an external magnetic field. The bandwidth coverage of 700MHz is obtained by designing correctly. Parametric study in return loss, gain and radiation pattern are studied here and other new points are presented as well.

  • Clutter Rank Estimation for Diving Platform Radar

    Fengde JIA  Zishu HE  

     
    LETTER-Analog Signal Processing

      Vol:
    E101-A No:3
      Page(s):
    600-603

    A convenient formula for the estimation of the clutter rank of the diving platform radar is derived. Brennan's rule provides a general formula to estimate the clutter rank for the side looking radar with a linear array, which is normally called one-dimensional (1D) estimation problem. With the help of the clutter wavenumber spectrum, the traditional estimation of the clutter rank is extended to the diving scenario and the estimation problem is two-dimensional (2D). The proposed rule is verified by the numerical simulations.

  • On the Second Separating Redundancy of LDPC Codes from Finite Planes

    Haiyang LIU  Yan LI  Lianrong MA  

     
    LETTER-Coding Theory

      Vol:
    E101-A No:3
      Page(s):
    617-622

    The separating redundancy is an important concept in the analysis of the error-and-erasure decoding of a linear block code using a parity-check matrix of the code. In this letter, we derive new constructive upper bounds on the second separating redundancies of low-density parity-check (LDPC) codes constructed from projective and Euclidean planes over the field Fq with q even.

  • An Efficient Content Search Method Based on Local Link Replacement in Unstructured Peer-to-Peer Networks

    Nagao OGINO  Takeshi KITAHARA  

     
    PAPER-Network

      Pubricized:
    2017/09/14
      Vol:
    E101-B No:3
      Page(s):
    740-749

    Peer-to-peer overlay networks can easily achieve a large-scale content sharing system on the Internet. Although unstructured peer-to-peer networks are suitable for finding entire partial-match content, flooding-based search is an inefficient way to obtain target content. When the shared content is semantically specified by a great number of attributes, it is difficult to derive the semantic similarity of peers beforehand. This means that content search methods relying on interest-based locality are more advantageous than those based on the semantic similarity of peers. Existing search methods that exploit interest-based locality organize multiple peer groups, in each of which peers with common interests are densely connected using short-cut links. However, content searches among multiple peer groups are still inefficient when the number of incident links at each peer is limited due to the capacity of the peer. This paper proposes a novel content search method that exploits interest-based locality. The proposed method can organize an efficient peer-to-peer network similar to the semantic small-world random graph, which can be organized by the existing methods based on the semantic similarity of peers. In the proposed method, topology transformation based on local link replacement maintains the numbers of incident links at all the peers. Simulation results confirm that the proposed method can achieve a significantly higher ratio of obtainable partial-match content than existing methods that organize peer groups.

161-180hit(1376hit)