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[Keyword] SI(16314hit)

6541-6560hit(16314hit)

  • Video Quality Assessment Using Spatio-Velocity Contrast Sensitivity Function

    Keita HIRAI  Jambal TUMURTOGOO  Ayano KIKUCHI  Norimichi TSUMURA  Toshiya NAKAGUCHI  Yoichi MIYAKE  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E93-D No:5
      Page(s):
    1253-1262

    Due to the development and popularization of high-definition televisions, digital video cameras, Blu-ray discs, digital broadcasting, IP television and so on, it plays an important role to identify and quantify video quality degradations. In this paper, we propose SV-CIELAB which is an objective video quality assessment (VQA) method using a spatio-velocity contrast sensitivity function (SV-CSF). In SV-CIELAB, motion information in videos is effectively utilized for filtering unnecessary information in the spatial frequency domain. As the filter to apply videos, we used the SV-CSF. It is a modulation transfer function of the human visual system, and consists of the relationship among contrast sensitivities, spatial frequencies and velocities of perceived stimuli. In the filtering process, the SV-CSF cannot be directly applied in the spatial frequency domain because spatial coordinate information is required when using velocity information. For filtering by the SV-CSF, we obtain video frames separated in spatial frequency domain. By using velocity information, the separated frames with limited spatial frequencies are weighted by contrast sensitivities in the SV-CSF model. In SV-CIELAB, the criteria are obtained by calculating image differences between filtered original and distorted videos. For the validation of SV-CIELAB, subjective evaluation experiments were conducted. The subjective experimental results were compared with SV-CIELAB and the conventional VQA methods such as CIELAB color difference, Spatial-CIELAB, signal to noise ratio and so on. From the experimental results, it was shown that SV-CIELAB is a more efficient VQA method than the conventional methods.

  • Complexity Scalability Design in the Internet Low Bit Rate Codec (iLBC) for Speech Coding

    Fu-Kun CHEN  Kuo-Bao KUO  

     
    PAPER-Speech and Hearing

      Vol:
    E93-D No:5
      Page(s):
    1238-1243

    Differing from the long-term prediction used in the modern speech codec, the standard of the internet low bit rate codec (iLBC) independently encodes the residual of the linear predictive coding (LPC) frame by frame. In this paper, a complexity scalability design is proposed for the coding of the dynamic codebook search in the iLBC speech codec. In addition, a trade-off between the computational complexity and the speech quality can be achieved by dynamically setting the parameter of the proposed approach. Simulation results show that the computational complexity can be effectively reduced with imperceptible degradation of the speech quality.

  • Acoustic Feature Transformation Based on Discriminant Analysis Preserving Local Structure for Speech Recognition

    Makoto SAKAI  Norihide KITAOKA  Kazuya TAKEDA  

     
    PAPER-Speech and Hearing

      Vol:
    E93-D No:5
      Page(s):
    1244-1252

    To improve speech recognition performance, feature transformation based on discriminant analysis has been widely used to reduce the redundant dimensions of acoustic features. Linear discriminant analysis (LDA) and heteroscedastic discriminant analysis (HDA) are often used for this purpose, and a generalization method for LDA and HDA, called power LDA (PLDA), has been proposed. However, these methods may result in an unexpected dimensionality reduction for multimodal data. It is important to preserve the local structure of the data when reducing the dimensionality of multimodal data. In this paper we introduce two methods, locality-preserving HDA and locality-preserving PLDA, to reduce dimensionality of multimodal data appropriately. We also propose an approximate calculation scheme to calculate sub-optimal projections rapidly. Experimental results show that the locality-preserving methods yield better performance than the traditional ones in speech recognition.

  • Improved Sequential Dependency Analysis Integrating Labeling-Based Sentence Boundary Detection

    Takanobu OBA  Takaaki HORI  Atsushi NAKAMURA  

     
    PAPER-Natural Language Processing

      Vol:
    E93-D No:5
      Page(s):
    1272-1281

    A dependency structure interprets modification relationships between words or phrases and is recognized as an important element in semantic information analysis. With the conventional approaches for extracting this dependency structure, it is assumed that the complete sentence is known before the analysis starts. For spontaneous speech data, however, this assumption is not necessarily correct since sentence boundaries are not marked in the data. Although sentence boundaries can be detected before dependency analysis, this cascaded implementation is not suitable for online processing since it delays the responses of the application. To solve these problems, we proposed a sequential dependency analysis (SDA) method for online spontaneous speech processing, which enabled us to analyze incomplete sentences sequentially and detect sentence boundaries simultaneously. In this paper, we propose an improved SDA integrating a labeling-based sentence boundary detection (SntBD) technique based on Conditional Random Fields (CRFs). In the new method, we use CRF for soft decision of sentence boundaries and combine it with SDA to retain its online framework. Since CRF-based SntBD yields better estimates of sentence boundaries, SDA can provide better results in which the dependency structure and sentence boundaries are consistent. Experimental results using spontaneous lecture speech from the Corpus of Spontaneous Japanese show that our improved SDA outperforms the original SDA with SntBD accuracy providing better dependency analysis results.

  • Gaussian Kernel-Based Multi-Histogram Equalization

    Suk Tae SEO  In Keun LEE  Hye Cheun JEONG  Soon Hak KWON  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E93-D No:5
      Page(s):
    1313-1316

    Histogram equalization is the most popular method for image enhancement. However it has some drawbacks: i) it causes undesirable artifacts and ii) it can degrade the visual quality. To overcome the drawbacks, in this letter, multi-histogram equalization on smoothed histogram using a Gaussian kernel is proposed. To demonstrate the effectiveness, the method is tested on several images and compared with conventional methods.

  • Strain Effects in van der Pauw (VDP) Stress Sensor Fabricated on (111) Silicon

    Chun-Hyung CHO  Ginkyu CHOI  Ho-Young CHA  

     
    BRIEF PAPER-Sensors

      Vol:
    E93-C No:5
      Page(s):
    640-643

    We have fabricated VDP (van der Pauw) stress sensors on (111) silicon surfaces. This work focuses on a study of strain effects in VDP stress sensors, which were generally ignored in previous works, for the precise measurements of die stresses in electronic packages. The stress sensitivity was observed to be approximately 10% larger for p-type VDP sensors compared to n-type VDP sensors.

  • A Simple Procedure for Classical Signal-Processing in Cluster-State Quantum Computation

    Kazuto OSHIMA  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E93-D No:5
      Page(s):
    1291-1293

    We exhibit a simple procedure to find how classical signals should be processed in cluster-state quantum computation. Using stabilizers characterizing a cluster state, we can easily find a precise classical signal-flow that is required in performing cluster-state computation.

  • Scalable Packet Classification with Hash Tables

    Pi-Chung WANG  

     
    LETTER

      Vol:
    E93-B No:5
      Page(s):
    1155-1158

    In the last decade, the technique of packet classification has been widely deployed in various network devices, including routers, firewalls and network intrusion detection systems. In this work, we improve the performance of packet classification by using multiple hash tables. The existing hash-based algorithms have superior scalability with respect to the required space; however, their search performance may not be comparable to other algorithms. To improve the search performance, we propose a tuple reordering algorithm to minimize the number of accessed hash tables with the aid of bitmaps. We also use pre-computation to ensure the accuracy of our search procedure. Performance evaluation based on both real and synthetic filter databases shows that our scheme is effective and scalable and the pre-computation cost is moderate.

  • A Simple DOCSIS Simulator

    Logan VOLKERS  Neil BARAKAT  Thomas DARCIE  

     
    LETTER-Network

      Vol:
    E93-B No:5
      Page(s):
    1268-1271

    DOCSIS is the defacto industry standard for cable internet to the home. In this letter, we examine the delay characteristics of commercially deployed DOCSIS networks. We focus on four mechanisms of the DOCSIS MAC operation and develop a computationally simple simulator to reproduce the phenomena produced by these mechanisms. In reproducing these phenomena using our simulator, we demonstrate that the simulator properly encapsulates the core mechanisms of DOCSIS and effectively simulates the delay of packets.

  • Synchronization Performance for OFDM-Based FM Systems Using Cyclic Delay Diversity

    Won-Jae SHIN  Young-Hwan YOU  

     
    LETTER-Broadcast Systems

      Vol:
    E93-B No:5
      Page(s):
    1338-1341

    Cyclic delay diversity (CDD) is a simple technique to intentionally increase frequency selectivity of channels for orthogonal frequency division multiplexing (OFDM). This letter evaluates the performance of post-FFT fine frequency estimation scheme for OFDM-based FM system using CDD. A new and accurate mean square error expression of the fine frequency estimator is derived in the CDD-based OFDM system, and simulation results are provided to verify our analysis.

  • Enhancement of the Programming Speed in SANOS Nonvolatile Memory Device Designed Utilizing Al2O3 and SiO2 Stacked Tunneling Layers

    Hyun Woo KIM  Dong Hun KIM  Joo Hyung YOU  Tae Whan KIM  

     
    BRIEF PAPER-Memory Devices

      Vol:
    E93-C No:5
      Page(s):
    651-653

    The programming characteristics of polysilicon-aluminum oxide-nitride-oxide-silicon (SANOS) nonvolatile memory devices with Al2O3 and SiO2 stacked tunneling layers were investigated. The electron and hole drifts in the Si3N4 layer were calculated to determine the program speed of the proposed SANOS devices. Simulation results showed that enhancement of the programming speed in SANOS was achieved by utilizing SiO2 and Al2O3 stacked tunneling layers.

  • Importance of the Electronic State on the Electrode in Electron Tunneling Processes between the Electrode and the Quantum Dot

    Masakazu MURAGUCHI  Yukihiro TAKADA  Shintaro NOMURA  Tetsuo ENDOH  Kenji SHIRAISHI  

     
    PAPER-Emerging Devices

      Vol:
    E93-C No:5
      Page(s):
    563-568

    We have revealed that the electronic states in the electrodes give a significant influence to the electron transport in nano-electronic devices. We have theoretically investigated the time-evolution of electron transport from a two-dimensional electron gas (2DEG) to a quantum dot (QD), where 2DEG represents the electrode in the nano-electronic devices. We clearly showed that the coherent electron transport is remarkably modified depending on the initial electronic state in the 2DEG. The electron transport from the 2DEG to the QD is strongly enhanced, when the initial state of the electron in the 2DEG is localized below the QD. We have proposed that controlling the electronic state in the electrodes could realize a new concept device function without modifying the electrode structures; that achieves a new controllable state in future nano-electronic devices.

  • On Best-Effort Packet Reordering for Mitigating the Effects of Out-of-Order Delivery on Unmodified TCP

    John Russell LANE  Akihiro NAKAO  

     
    PAPER

      Vol:
    E93-B No:5
      Page(s):
    1095-1103

    Multipath routing and the ability to simultaneously use multiple network paths has long been proposed as a means for meeting the reliability and performance improvement goals of a next generation Internet. However, its use causes out-of-order packet delivery, which is well known to hinder TCP performance. While next-generation transport protocols will no doubt better cope with this phenomenon, a complete switch to these new protocols cannot be made on all devices "overnight"; the reality is that we will be forced to continue using TCP on such multipath networks well after deployment of a future Internet is complete. In this paper, we investigate the use of best-effort packet reordering -- an optional network layer service for improving the performance of any TCP session in the presence of out-of-order packet delivery. Such a service holds the promise of allowing unmodified TCP to take advantage of the reliability and performance gains offered by a future multipath-enabled Internet without suffering the adverse performance effects commonly associated with out-of-order packet delivery. Our experiments test the performance of two common TCP variants under packet dispersion with differing numbers of paths and amounts of inter-path latency variance. They were conducted using multipath network and packet reorderer implementations implemented within the Emulab testbed. Our results demonstrate that a simple best-effort reordering service can insulate TCP from the type of reordering that might be expected from use of packet dispersion over disjoint paths in a wide-area network, and is capable of providing significant performance benefits with few ill side-effects.

  • A Class of Near Shift-Invariant and Orientation-Selective Transform Based on Delay-Less Oversampled Even-Stacked Cosine-Modulated Filter Banks

    Seisuke KYOCHI  Masaaki IKEHARA  

     
    PAPER-Digital Signal Processing

      Vol:
    E93-A No:4
      Page(s):
    724-733

    The purpose of this study is to show a class of near shift-invariant and orientation-selective transform based on even-stacked cosine-modulated filter banks (ECFBs) which originally have been proposed by Lin and Vaidyanathan. It is well-known that ECFBs can be designed by the modulation of just one prototype filter and guarantee the linear phase property. We extend this class to delay-less oversampled ECFB and show two additional attractive features; high directional selectivity and near shift-invariant property. In this paper, these properties are verified by theoretical analysis and demonstrations.

  • Novel Joint Source-Channel Coding of Periodic ECG Signals for Reliable Wireless Patient Monitoring

    Katsuhiro WATANABE  Kenichi TAKIZAWA  Tetsushi IKEGAMI  

     
    PAPER

      Vol:
    E93-B No:4
      Page(s):
    819-825

    This paper proposes a joint source-channel coding technology to transmit periodic vital information such as an electrocardiogram. There is an urgent need for a ubiquitous medical treatment space in which personalized medical treatment is automatically provided based on measured vital information. To realize such treatment and reduce the constraints on the patient, wireless transmission of vital information from a sensor device to a data aggregator is essential. However, the vital information has to be correctly conveyed through wireless channels. In addition, sensor devices are constrained by their battery power. Thus, a coding technique that provides robustness to noise, channel efficiency and low power consumption at encoding is essential. This paper presents a coding method that uses correlation of periodic vital information in the time domain, and provides a decoding scheme that uses the correlation as side information in a maximum a posteriori probability algorithm. Our results show that the proposed method provides better performance in terms of mean squared error after decoding in comparison to differential pulse-code modulation, and the uncoded case.

  • Design of Narrow Wall Windows in a Waveguide to Feed Partially-Dielectric-Filled Oversized-Rectangular Waveguide Based on 2-Dimensional Analyses of Two Orthogonal Directions

    Miroslav SAMARDIJA  Jiro HIROKAWA  Makoto ANDO  

     
    PAPER-Devices/Circuits for Communications

      Vol:
    E93-B No:4
      Page(s):
    871-878

    A series of windows in the narrow wall of a fully-dielectric-filled rectangular waveguide to feed partially-dielectric-filled oversized-rectangular waveguide is presented. The overall structure is single-layer and 3-dimensional however; the waveguide which is uniform along the height is analyzed by the 2-dimensional method of moments and the oversized waveguide which is uniform in the longitudinal direction of the waveguide is analyzed by the 2-dimensional mode matching. It is found that utilizing simple mode conversions between the two orthogonally uniform structures is sufficient for obtaining the results similar to those of a 3-dimensional solver HFSS. The parameters for the windows designed for a uniform input division are presented. A simulation shows that a 12 window array provides a 3.5% bandwidth in terms of reflection below -20 dB. The uniform excitation of the quasi-TEM wave is confirmed in the 60 GHz band by measuring a uniform aperture field in amplitude and phase over the slotted oversized-waveguide.

  • Compact CAD Models for the Signal Integrity Verification of Multi-Coupled Transmission Lines

    Hyunsik KIM  Yungseon EO  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E93-A No:4
      Page(s):
    752-760

    A novel modal signal decoupling algorithm for multi-coupled transmission lines is developed. Since the proposed method exploits a set of basis vectors associated with the characteristic impedances of the transmission line system, these multi-coupled signals can be efficiently decoupled regardless of dielectric media and conductors. Thus, compact forms of the signal integrity verification CAD models for multi-coupled transmission lines can be readily determined. It is shown that the analytical models are in excellent agreement with those obtained with SPICE simulation and its computation time is much faster than the conventional macro model (W-model) in the order of two.

  • Theoretical Analysis of Density Ratio Estimation

    Takafumi KANAMORI  Taiji SUZUKI  Masashi SUGIYAMA  

     
    PAPER-Algorithms and Data Structures

      Vol:
    E93-A No:4
      Page(s):
    787-798

    Density ratio estimation has gathered a great deal of attention recently since it can be used for various data processing tasks. In this paper, we consider three methods of density ratio estimation: (A) the numerator and denominator densities are separately estimated and then the ratio of the estimated densities is computed, (B) a logistic regression classifier discriminating denominator samples from numerator samples is learned and then the ratio of the posterior probabilities is computed, and (C) the density ratio function is directly modeled and learned by minimizing the empirical Kullback-Leibler divergence. We first prove that when the numerator and denominator densities are known to be members of the exponential family, (A) is better than (B) and (B) is better than (C). Then we show that once the model assumption is violated, (C) is better than (A) and (B). Thus in practical situations where no exact model is available, (C) would be the most promising approach to density ratio estimation.

  • Distributed Cooperative Routing Algorithm for Multi-Hop Multi-Relay Wireless Networks

    ASADUZZAMAN  Hyung-Yun KONG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:4
      Page(s):
    1049-1052

    Motivated by the recent research in crosslayer design of cooperative wireless network, we propose a distributed cooperative routing algorithm for a multihop multi-relay wireless network to achieve selection diversity. We propose two algorithms, rate optimal path selection and outage optimal path selection, to satisfy the different requirements of the systems. Both algorithms work on distributed processing without requiring any centralized controller. Simulations are conducted to evaluate the performance of the proposal. The results of the simulations show that the proposed routing algorithms significantly improve the end-to-end data rate and outage performance compared with noncooperative routing protocols.

  • An Improved Anchor Shot Detection Method Using Fitness of Face Location and Dissimilarity of Icon Region

    Ji-Soo KEUM  Hyon-Soo LEE  Masafumi HAGIWARA  

     
    LETTER-Image

      Vol:
    E93-A No:4
      Page(s):
    863-866

    In this letter, we propose an improved anchor shot detection (ASD) method in order to effectively retrieve anchor shots from news video. The face location and dissimilarity of icon region are used to reduce false alarms in the proposed method. According to the results of the experiment on several types of news video, the proposed method obtained high anchor detection results compared with previous methods.

6541-6560hit(16314hit)