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

Keyword Search Result

[Keyword] ATI(18690hit)

7481-7500hit(18690hit)

  • The Design of a Total Ship Service Framework Based on a Ship Area Network

    Daekeun MOON  Kwangil LEE  Hagbae KIM  

     
    LETTER-Dependable Computing

      Vol:
    E93-D No:10
      Page(s):
    2858-2861

    The rapid growth of IT technology has enabled ship navigation and automation systems to gain better functionality and safety. However, they generally have their own proprietary structures and networks, which makes interfacing with and remote access to them difficult. In this paper, we propose a total ship service framework that includes a ship area network to integrate separate system networks with heterogeneity and dynamicity, and a ship-shore communication infrastructure to support a remote monitoring and maintenance service using satellite communications. Finally, we present some ship service systems to demonstrate the applicability of the proposed framework.

  • A Priority Routing Protocol Based on Location and Moving Direction in Delay Tolerant Networks

    Jian SHEN  Sangman MOH  Ilyong CHUNG  

     
    PAPER-Information Network

      Vol:
    E93-D No:10
      Page(s):
    2763-2775

    Delay Tolerant Networks (DTNs) are a class of emerging networks that experience frequent and long-duration partitions. Delay is inevitable in DTNs, so ensuring the validity and reliability of the message transmission and making better use of buffer space are more important than concentrating on how to decrease the delay. In this paper, we present a novel routing protocol named Location and Direction Aware Priority Routing (LDPR) for DTNs, which utilizes the location and moving direction of nodes to deliver a message from source to destination. A node can get its location and moving direction information by receiving beacon packets periodically from anchor nodes and referring to received signal strength indicator (RSSI) for the beacon. LDPR contains two schemes named transmission scheme and drop scheme, which take advantage of the nodes' information of the location and moving direction to transmit the message and store the message into buffer space, respectively. Each message, in addition, is branded a certain priority according to the message's attributes (e.g. importance, validity, security and so on). The message priority decides the transmission order when delivering the message and the dropping sequence when the buffer is full. Simulation results show that the proposed LDPR protocol outperforms epidemic routing (EPI) protocol, prioritized epidemic routing (PREP) protocol, and DTN hierarchical routing (DHR) protocol in terms of packet delivery ratio, normalized routing overhead and average end-to-end delay. It is worth noting that LDPR doesn't need infinite buffer size to ensure the packet delivery ratio as in EPI. In particular, even though the buffer size is only 50, the packet delivery ratio of LDPR can still reach 93.9%, which can satisfy general communication demand. We expect LDPR to be of greater value than other existing solutions in highly disconnected and mobile networks.

  • Improved Measurement Accuracy of a Laser Interferometer: Extended Kalman Filter Approach

    Wooram LEE  Dongkyun KIM  Kwanho YOU  

     
    LETTER-Systems and Control

      Vol:
    E93-A No:10
      Page(s):
    1820-1823

    In this paper a nonlinearity compensation algorithm based on the extended Kalman filter is proposed to improve the measurement accuracy of a heterodyne laser interferometer. The heterodyne laser interferometer is used for ultra-precision measurements such as those used in semiconductor manufacturing. However the periodical nonlinearity property caused by frequency-mixing restricts the accuracy of the nanometric measurements. In order to minimize the effect of the nonlinearity, the measurement process of the laser interferometer is modeled as a state equation and the extended Kalman filtering approach is applied to the process. The effectiveness of our proposed algorithm is demonstrated by comparing the results of the algorithm with experimental results for the laser system.

  • A Semi-Supervised Approach to Perceived Age Prediction from Face Images

    Kazuya UEKI  Masashi SUGIYAMA  Yasuyuki IHARA  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E93-D No:10
      Page(s):
    2875-2878

    We address the problem of perceived age estimation from face images, and propose a new semi-supervised approach involving two novel aspects. The first novelty is an efficient active learning strategy for reducing the cost of labeling face samples. Given a large number of unlabeled face samples, we reveal the cluster structure of the data and propose to label cluster-representative samples for covering as many clusters as possible. This simple sampling strategy allows us to boost the performance of a manifold-based semi-supervised learning method only with a relatively small number of labeled samples. The second contribution is to take the heterogeneous characteristics of human age perception into account. It is rare to misjudge the age of a 5-year-old child as 15 years old, but the age of a 35-year-old person is often misjudged as 45 years old. Thus, magnitude of the error is different depending on subjects' age. We carried out a large-scale questionnaire survey for quantifying human age perception characteristics, and propose to utilize the quantified characteristics in the framework of weighted regression. Consequently, our proposed method is expressed in the form of weighted least-squares with a manifold regularizer, which is scalable to massive datasets. Through real-world age estimation experiments, we demonstrate the usefulness of the proposed method.

  • A Comparative Investigation of Several Frequency Modulation Profiles for Programmed Switching Controllers Targeted Conducted-Noise Reduction in DC-DC Converters

    Gamal M. DOUSOKY  Masahito SHOYAMA  Tamotsu NINOMIYA  

     
    PAPER

      Vol:
    E93-B No:9
      Page(s):
    2265-2272

    This paper investigates the effect of several frequency modulation profiles on conducted-noise reduction in dc-dc converters with programmed switching controller. The converter is operated in variable frequency modulation regime. Twelve switching frequency modulation profiles have been studied. Some of the modulation data are prepared using MATLAB software, and others are generated online. Moreover, all the frequency profiles have been designed and implemented using FPGA and experimentally investigated. The experimental results show that the conducted-noise spreading depends on both the modulation sequence profile and the statistical characteristics of the sequence. A substantial part of the manufacturing cost of power converters for telecommunication applications involves designing filters to comply with the EMI limits. Considering this investigation significantly reduces the filter size.

  • Unsupervised Speaker Adaptation Using Speaker-Class Models for Lecture Speech Recognition

    Tetsuo KOSAKA  Yuui TAKEDA  Takashi ITO  Masaharu KATO  Masaki KOHDA  

     
    PAPER-Adaptation

      Vol:
    E93-D No:9
      Page(s):
    2363-2369

    In this paper, we propose a new speaker-class modeling and its adaptation method for the LVCSR system and evaluate the method on the Corpus of Spontaneous Japanese (CSJ). In this method, closer speakers are selected from training speakers and the acoustic models are trained by using their utterances for each evaluation speaker. One of the major issues of the speaker-class model is determining the selection range of speakers. In order to solve the problem, several models which have a variety of speaker range are prepared for each evaluation speaker in advance, and the most proper model is selected on a likelihood basis in the recognition step. In addition, we improved the recognition performance using unsupervised speaker adaptation with the speaker-class models. In the recognition experiments, a significant improvement could be obtained by using the proposed speaker adaptation based on speaker-class models compared with the conventional adaptation method.

  • Least Absolute Policy Iteration--A Robust Approach to Value Function Approximation

    Masashi SUGIYAMA  Hirotaka HACHIYA  Hisashi KASHIMA  Tetsuro MORIMURA  

     
    PAPER-Artificial Intelligence, Data Mining

      Vol:
    E93-D No:9
      Page(s):
    2555-2565

    Least-squares policy iteration is a useful reinforcement learning method in robotics due to its computational efficiency. However, it tends to be sensitive to outliers in observed rewards. In this paper, we propose an alternative method that employs the absolute loss for enhancing robustness and reliability. The proposed method is formulated as a linear programming problem which can be solved efficiently by standard optimization software, so the computational advantage is not sacrificed for gaining robustness and reliability. We demonstrate the usefulness of the proposed approach through a simulated robot-control task.

  • Efficient Speech Reinforcement Based on Low-Bit-Rate Speech Coding Parameters

    Jae-Hun CHOI  Joon-Hyuk CHANG  Seong-Ro LEE  

     
    LETTER-Speech and Hearing

      Vol:
    E93-A No:9
      Page(s):
    1684-1687

    In this paper, a novel approach to speech reinforcement in a low-bit-rate speech coder under ambient noise environments is proposed. The excitation vector of ambient noise is efficiently obtained at the near-end and then combined with the excitation signal of the far-end for a suitable reinforcement gain within the G.729 CS-ACELP Annex. B framework. For this reason, this can be clearly different from previous approaches in that the present approach does not require an additional arithmetic step such as the discrete Fourier transform (DFT). Experimental results indicate that the proposed method shows better performance than or at least comparable to conventional approaches with a lower computational burden.

  • A Single Event Effect Analysis on Static CVSL Exclusive-OR Circuits

    Hiroshi HATANO  

     
    BRIEF PAPER-Semiconductor Materials and Devices

      Vol:
    E93-C No:9
      Page(s):
    1471-1473

    Single event transient (SET) effects on original static cascade voltage switch logic (CVSL) exclusive-OR (EX-OR) circuits have been investigated using SPICE. SET simulation results have confirmed that the static CVSL EX-OR circuits have increased tolerance to SET. The static CVSL EX-OR circuit is more than 200 times harder than the conventional CMOS circuit.

  • Structural Models that Manage IT Portfolio Affecting Business Value of Enterprise Architecture

    Takaaki KAMOGAWA  

     
    PAPER-Office Information Systems, e-Business Modeling

      Vol:
    E93-D No:9
      Page(s):
    2566-2576

    This paper examines the structural relationships between Information Technology (IT) governance and Enterprise Architecture (EA), with the objective of enhancing business value in the enterprise society. Structural models consisting of four related hypotheses reveal the relationship between IT governance and EA in the improvement of business values. We statistically examined the hypotheses by analyzing validated questionnaire items from respondents within firms listed on the Japanese stock exchange who were qualified to answer them. We concluded that firms which have organizational ability controlled by IT governance are more likely to deliver business value based on IT portfolio management.

  • Lightweight Precision-Adaptive Time Synchronization in Wireless Sensor Networks

    Li LI  Yongpan LIU  Huazhong YANG  Hui WANG  

     
    PAPER-Network

      Vol:
    E93-B No:9
      Page(s):
    2299-2308

    Time synchronization is an essential service for wireless sensor networks (WSNs). However, fixed-period time synchronization can not serve multiple users efficiently in terms of energy consumption. This paper proposes a lightweight precision-adaptive protocol for cluster-based multi-user networks. It consists of a basic average time synchronization algorithm and an adaptive control loop. The basic average time synchronization algorithm achieves 1 µs instantaneous synchronization error performance. It also prolongs re-synchronization period by taking the average of two specified nodes' local time to be cluster global time. The adaptive control loop realizes diverse levels of synchronization precision based on the proportional relationship between sync error and re-synchronization period. Experimental results show that the proposed precision-adaptive protocol can respond to the sync error bound change within 2 steps. It is faster than the exponential convergence of the adaptive protocols based on multiplicative iterations.

  • Population Estimation of RFID Tags Using Hadamard Footprints

    Joontae KIM  Seung-Ri JIN  Dong-Jo PARK  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:9
      Page(s):
    2473-2476

    A novel method is proposed that can estimate the tag population in Radio Frequency Identification (RFID) systems by using a Hadamard code for the tag response. We formulate the maximum likelihood estimator for the tag population using the number of observed footprints. The lookup table of the estimation algorithm has low complexity. Simulation results show that the proposed estimator performs considerably better than the conventional schemes.

  • Practical Power Allocation for Cooperative Distributed Antenna Systems

    Wei FENG  Yanmin WANG  Yunzhou LI  Shidong ZHOU  Jing WANG  

     
    LETTER-Fundamental Theories for Communications

      Vol:
    E93-B No:9
      Page(s):
    2424-2427

    In this letter, we address the problem of downlink power allocation for the generalized distributed antenna system (DAS) with cooperative clusters. Considering practical applications, we assume that only the large-scale channel state information is available at the transmitter. The power allocation scheme is investigated with the target of ergodic achievable sum rate maximization. Based on some approximations and the Rayleigh Quotient Theory, the simple selective power allocation scheme is derived for the low SNR scenario and the high SNR scenario, respectively. The methods are applicable in practice due to their low complexity.

  • Commercial Shot Classification Based on Multiple Features Combination

    Nan LIU  Yao ZHAO  Zhenfeng ZHU  Rongrong NI  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E93-D No:9
      Page(s):
    2651-2655

    This paper presents a commercial shot classification scheme combining well-designed visual and textual features to automatically detect TV commercials. To identify the inherent difference between commercials and general programs, a special mid-level textual descriptor is proposed, aiming to capture the spatio-temporal properties of the video texts typical of commercials. In addition, we introduce an ensemble-learning based combination method, named Co-AdaBoost, to interactively exploit the intrinsic relations between the visual and textual features employed.

  • A Parallel Transmission Scheme for All-to-All Broadcast in Underwater Sensor Networks

    Soonchul PARK  Jaesung LIM  

     
    PAPER-Network

      Vol:
    E93-B No:9
      Page(s):
    2309-2315

    This paper is concerned with the packet transmission scheduling problem for repeating all-to-all broadcasts in Underwater Sensor Networks (USN) in which there are n nodes in a transmission range. All-to-all communication is one of the most dense communication patterns. It is assumed that each node has the same size packet. Unlike the terrestrial scenarios, the propagation time in underwater communications is not negligible. We define all-to-all broadcast as the one where every node transmits packets to all the other nodes in the network except itself. So, there are in total n(n - 1) packets to be transmitted for an all-to-all broadcast. The optimal transmission scheduling is to schedule in a way that all packets can be transmitted within the minimum time. In this paper, we propose an efficient packet transmission scheduling algorithm for underwater acoustic communications using the property of long propagation delay.

  • Strongly Secure Privacy Amplification Cannot Be Obtained by Encoder of Slepian-Wolf Code

    Shun WATANABE  Ryutaroh MATSUMOTO  Tomohiko UYEMATSU  

     
    PAPER-Information Theory

      Vol:
    E93-A No:9
      Page(s):
    1650-1659

    Privacy amplification is a technique to distill a secret key from a random variable by a function so that the distilled key and eavesdropper's random variable are statistically independent. There are three kinds of security criteria for the key distilled by privacy amplification: the normalized divergence criterion, which is also known as the weak security criterion, the variational distance criterion, and the divergence criterion, which is also known as the strong security criterion. As a technique to distill a secret key, it is known that the encoder of a Slepian-Wolf (the source coding with full side-information at the decoder) code can be used as a function for privacy amplification if we employ the weak security criterion. In this paper, we show that the encoder of a Slepian-Wolf code cannot be used as a function for privacy amplification if we employ the criteria other than the weak one.

  • Correcting Syntactic Annotation Errors Using a Synchronous Tree Substitution Grammar

    Yoshihide KATO  Shigeki MATSUBARA  

     
    LETTER-Natural Language Processing

      Vol:
    E93-D No:9
      Page(s):
    2660-2663

    This paper proposes a method of correcting annotation errors in a treebank. By using a synchronous grammar, the method transforms parse trees containing annotation errors into the ones whose errors are corrected. The synchronous grammar is automatically induced from the treebank. We report an experimental result of applying our method to the Penn Treebank. The result demonstrates that our method corrects syntactic annotation errors with high precision.

  • MV-OPES: Multivalued-Order Preserving Encryption Scheme: A Novel Scheme for Encrypting Integer Value to Many Different Values

    Hasan KADHEM  Toshiyuki AMAGASA  Hiroyuki KITAGAWA  

     
    PAPER-Data Engineering, Web Information Systems

      Vol:
    E93-D No:9
      Page(s):
    2520-2533

    Encryption can provide strong security for sensitive data against inside and outside attacks. This is especially true in the "Database as Service" model, where confidentiality and privacy are important issues for the client. In fact, existing encryption approaches are vulnerable to a statistical attack because each value is encrypted to another fixed value. This paper presents a novel database encryption scheme called MV-OPES (Multivalued--Order Preserving Encryption Scheme), which allows privacy-preserving queries over encrypted databases with an improved security level. Our idea is to encrypt a value to different multiple values to prevent statistical attacks. At the same time, MV-OPES preserves the order of the integer values to allow comparison operations to be directly applied on encrypted data. Using calculated distance (range), we propose a novel method that allows a join query between relations based on inequality over encrypted values. We also present techniques to offload query execution load to a database server as much as possible, thereby making a better use of server resources in a database outsourcing environment. Our scheme can easily be integrated with current database systems as it is designed to work with existing indexing structures. It is robust against statistical attack and the estimation of true values. MV-OPES experiments show that security for sensitive data can be achieved with reasonable overhead, establishing the practicability of the scheme.

  • Complexity Suppression of Neural Networks for PAPR Reduction of OFDM Signal

    Masaya OHTA  Keiichi MIZUTANI  Katsumi YAMASHITA  

     
    LETTER-Spread Spectrum Technologies and Applications

      Vol:
    E93-A No:9
      Page(s):
    1704-1708

    In this letter, a neural network (NN) for peak power reduction of an orthogonal frequency-division multiplexing (OFDM) signal is improved in order to suppress its computational complexity. Numerical experiments show that the amount of IFFTs in the proposed NN can be reduced to half, and its computational time can be reduced by 21.5% compared with a conventional NN. In comparison with the SLM, the proposed NN is effective to achieve high PAPR reduction and it has an advantage over the SLM under the equal computational condition.

  • Improvements of the One-to-Many Eigenvoice Conversion System

    Yamato OHTANI  Tomoki TODA  Hiroshi SARUWATARI  Kiyohiro SHIKANO  

     
    PAPER-Voice Conversion

      Vol:
    E93-D No:9
      Page(s):
    2491-2499

    We have developed a one-to-many eigenvoice conversion (EVC) system that allows us to convert a single source speaker's voice into an arbitrary target speaker's voice using an eigenvoice Gaussian mixture model (EV-GMM). This system is capable of effectively building a conversion model for an arbitrary target speaker by adapting the EV-GMM using only a small amount of speech data uttered by the target speaker in a text-independent manner. However, the conversion performance is still insufficient for the following reasons: 1) the excitation signal is not precisely modeled; 2) the oversmoothing of the converted spectrum causes muffled sounds in converted speech; and 3) the conversion model is affected by redundant acoustic variations among a lot of pre-stored target speakers used for building the EV-GMM. In order to address these problems, we apply the following promising techniques to one-to-many EVC: 1) mixed excitation; 2) a conversion algorithm considering global variance; and 3) adaptive training of the EV-GMM. The experimental results demonstrate that the conversion performance of one-to-many EVC is significantly improved by integrating all of these techniques into the one-to-many EVC system.

7481-7500hit(18690hit)