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2261-2280hit(8214hit)

  • An Optimized Auto-tuning Digital DC--DC Converter Based on Linear-Non-Linear and Predictive PID

    Chuang WANG  Zunchao LI  Cheng LUO  Lijuan ZHAO  Yefei ZHANG  Feng LIANG  

     
    PAPER-Electronic Circuits

      Vol:
    E97-C No:8
      Page(s):
    813-819

    A novel auto-tuning digital DC--DC converter is presented. In order to reduce the recovery time and undershoot, the auto-tuning control combines LnL, conventional PID and a predictive PID with a configurable predictive coefficient. A switch module is used to select an algorithm from the three control algorithms, according to the difference between the error signal and the two initially predefined thresholds. The detection and control logic is designed for both window delay line ADC and $Sigma Delta$ DPWM to correct the delay deviation. When the output of the converter exceeds the quantization range, the digital output of ADC is set at 0 or 1, and the delay line stops working to reduce power consumption. Theoretical analysis and simulations in the CSMC CMOS 0.5,$mu$m process are carried out to verify the proposed DC--DC converter. It is found that the converter achieves a power efficiency of more than 90% at heavy load, and reduces the recovery time and undershoot.

  • Incorporating Olfactory into a Multi-Modal Surgical Simulation

    Osama HALABI  Fatma AL-MESAIFRI  Mariam AL-ANSARI  Roqaya AL-SHAABI  Kazunori MIYATA  

     
    LETTER-Multimodality

      Vol:
    E97-D No:8
      Page(s):
    2048-2052

    This paper proposes a novel multimodal interactive surgical simulator that incorporates haptic, olfactory, as well as traditional vision feedback. A scent diffuser was developed to produce odors when errors occur. Haptic device was used to provide the sense of touch to the user. The preliminary results show that adding smell as an aid to the simulation enhanced the memory retention that lead to better performance.

  • Katakana EdgeWrite: An EdgeWrite Version for Japanese Text Entry

    Kentaro GO  Yuichiro KINOSHITA  

     
    LETTER-Interaction

      Vol:
    E97-D No:8
      Page(s):
    2053-2054

    This paper presents our project of designing EdgeWrite text entry methods for Japanese language. We are developing a version of EdgeWrite text entry method for Japanese language: Katakana EdgeWrite. Katakana EdgeWrite specifies the line stroke directions and writing order of the Japanese Katakana character. The ideal corner sequence pattern of EdgeWrite for each Katakana character is designed based on its line stroke directions and writing order.

  • Trajectory Outlier Detection Based on Multi-Factors

    Lei ZHANG  Zimu HU  Guang YANG  

     
    LETTER-Data Engineering, Web Information Systems

      Vol:
    E97-D No:8
      Page(s):
    2170-2173

    Most existing outlier detection algorithms only utilized location of trajectory points and neglected some important factors such as speed, acceleration, and corner. To address this problem, we present a Trajectory Outlier Detection algorithm based on Multi-Factors (TODMF). TODMF is improved in terms of distance-based outlier detection algorithms. It combines multi-factors into outlier detection to find more meaningful trajectory outliers. We resort to Canonical Correlation Analysis (CCA) to optimize the number of factors when determining what factors will be considered. Finally, the experiments with real trajectory data sets show that TODMF performs efficiently and effectively when applied to the problem of trajectory outlier detection.

  • A Personality Model Based on NEO PI-R for Emotion Simulation

    Yi ZHANG  Ling LI  

     
    PAPER-Affective Computing

      Vol:
    E97-D No:8
      Page(s):
    2000-2007

    The last decade has witnessed an explosion of interest in research on human emotion modeling for generating intelligent virtual agents. This paper proposes a novel personality model based on the Revised NEO Personality Inventory (NEO PI-R). Compared to the popular Big-Five-Personality Factors (Big5) model, our proposed model is more capable than Big5 on describing a variety of personalities. Combining with emotion models it helps to produce more reasonable emotional reactions to external stimuli. A novel Resistant formulation is also proposed to effectively simulate the complicated negative emotions. Emotional reactions towards multiple stimuli are also effectively simulated with the proposed personality model.

  • Activity Recognition Based on an Accelerometer in a Smartphone Using an FFT-Based New Feature and Fusion Methods

    Yang XUE  Yaoquan HU  Lianwen JIN  

     
    LETTER-Human-computer Interaction

      Vol:
    E97-D No:8
      Page(s):
    2182-2186

    With the development of personal electronic equipment, the use of a smartphone with a tri-axial accelerometer to detect human physical activity is becoming popular. In this paper, we propose a new feature based on FFT for activity recognition from tri-axial acceleration signals. To improve the classification performance, two fusion methods, minimal distance optimization (MDO) and variance contribution ranking (VCR), are proposed. The new proposed feature achieves a recognition rate of 92.41%, which outperforms six traditional time- or frequency-domain features. Furthermore, the proposed fusion methods effectively improve the recognition rates. In particular, the average accuracy based on class fusion VCR (CFVCR) is 97.01%, which results in an improvement in accuracy of 4.14% compared with the results without any fusion. Experiments confirm the effectiveness of the new proposed feature and fusion methods.

  • Effective PPS Signal Generation with Predictive Synchronous Loop for GPS

    YanBin ZHANG  WeiJun LU  DengYun LEI  YongCan HUANG  DunShan YU  

     
    PAPER-Navigation, Guidance and Control Systems

      Vol:
    E97-B No:8
      Page(s):
    1742-1749

    The Global Position System (GPS), which is well known as a global tool for positioning, is also the primary system for time transfer. GPS can deliver very precise time to every corner of the world. Usually, a GPS receiver indicates the precise time by means of the 1PPS (one pulse per second) signal. This paper studies the precise time transfer system structure of GPS receivers and then proposes an effective PPS signal generation method with predictive synchronous loop, combining phase error prediction and dynamic threshold adjustment. A GPS time transfer system is implemented and measured in detail to demonstrate the validity of the proposed algorithm. Assuming the receiver clock rate of 16.368MHz, the proposed method can achieve the accuracy of ±20ns in the scope 1δ which can meet the requirements of the vast majority of occasions. Through a long period of testing, we prove the feasibility of this algorithm experimentally.

  • Anatomy of a Digital Coherent Receiver Open Access

    Robert BORKOWSKI  Darko ZIBAR  Idelfonso TAFUR MONROY  

     
    INVITED PAPER

      Vol:
    E97-B No:8
      Page(s):
    1528-1536

    Digital coherent receivers have gained significant attention in the last decade. The reason for this is that coherent detection, along with digital signal processing (DSP) allows for substantial increase of the channel capacity by employing advanced detection techniques. In this paper, we first review coherent detection technique employed in the receiver as well as the required receiver structure. Subsequently, we describe the core part of the receiver — DSP algorithms — that are used for data processing. We cover all basic elements of a conventional coherent receiver DSP chain: deskew, orthonormaliation, chromatic dispersion compensation/nonlinear compensation, resampling and timing recovery, polarization demultiplexing and equalization, frequency and phase recovery, digital demodulation. We also describe novel subsystems of a digital coherent receiver: modulation format recognition and impairment mitigation via expectation maximization, which may gain popularity with increasing importance of autonomous networks.

  • Revocable Identity-Based Encryption with Rejoin Functionality

    Jae Hong SEO  Keita EMURA  

     
    LETTER-Cryptography and Information Security

      Vol:
    E97-A No:8
      Page(s):
    1806-1809

    In the Identity-Based Encryption (IBE) setting, the rejoin functionality seems to be impossible since each user has the unique identity as its public key. Moreover, sometimes these identities are unchangeable, e.g., biological information (finger print iris, and so on) is regarded as the identity. Even if changeable value is indicated as an identity, e.g., e-mail address, it is preferable that the same identity can be used after a secret key is leaked. In this paper, we give a formal security definition of RIBE with the rejoin functionality, and also show that the Seo-Emura RIBE scheme [PKC 2013] (with a slight modification) has the rejoin functionality.

  • A Structured Routing Architecture for Practical Application of Character Projection Method in Electron-Beam Direct Writing

    Rimon IKENO  Takashi MARUYAMA  Satoshi KOMATSU  Tetsuya IIZUKA  Makoto IKEDA  Kunihiro ASADA  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E97-A No:8
      Page(s):
    1688-1698

    To improve throughput of Electron Beam Direct Writing (EBDW) with Character Projection (CP) method, a structured routing architecture (SRA) has been proposed to restrict VIA placement and wire-track transition. It reduces possible layout patterns in the interconnect layers, and increases VIA and metal figure numbers in the EB shots while suppressing the CP character number explosion. In this paper, we discuss details of the SRA design methodology, and demonstrate the CP performance by SRA in comparison with other EBDW techniques. Our experimental results show viable CP performance for practical use, and prove SRA's feasibility in 14nm mass fabrication.

  • Comparison of Output Devices for Augmented Audio Reality

    Kazuhiro KONDO  Naoya ANAZAWA  Yosuke KOBAYASHI  

     
    PAPER-Speech and Hearing

      Vol:
    E97-D No:8
      Page(s):
    2114-2123

    We compared two audio output devices for augmented audio reality applications. In these applications, we plan to use speech annotations on top of the actual ambient environment. Thus, it becomes essential that these audio output devices are able to deliver intelligible speech annotation along with transparent delivery of the environmental auditory scene. Two candidate devices were compared. The first output was the bone-conduction headphone, which can deliver speech signals by vibrating the skull, while normal hearing is left intact for surrounding noise since these headphones leave the ear canals open. The other is the binaural microphone/earphone combo, which is in a form factor similar to a regular earphone, but integrates a small microphone at the ear canal entry. The input from these microphones can be fed back to the earphones along with the annotation speech. We also compared these devices to normal hearing (i.e., without headphones or earphones) for reference. We compared the speech intelligibility when competing babble noise is simultaneously given from the surrounding environment. It was found that the binaural combo can generally deliver speech signals at comparable or higher intelligibility than the bone-conduction headphones. However, with the binaural combo, we found that the ear canal transfer characteristics were altered significantly by shutting the ear canals closed with the earphones. Accordingly, if we employed a compensation filter to account for this transfer function deviation, the resultant speech intelligibility was found to be significantly higher. However, both of these devices were found to be acceptable as audio output devices for augmented audio reality applications since both are able to deliver speech signals at high intelligibility even when a significant amount of competing noise is present. In fact, both of these speech output methods were able to deliver speech signals at higher intelligibility than natural speech, especially when the SNR was low.

  • Cryptanalysis of Double-Block-Length Hash Modes MDC-4 and MJH

    Deukjo HONG  Daesung KWON  

     
    PAPER-Cryptography and Information Security

      Vol:
    E97-A No:8
      Page(s):
    1747-1753

    We give some attacks on the DBL hash modes MDC-4 and MJH. Our preimage attack on the MDC-4 hash function requires the time complexity O(23n/2) for the block length n of the underlying block cipher, which significantly improves the previous results. Our collision attack on the MJH hash function has a time complexity less than 2124 for n=128. Our preimage attack on the the MJH compression function finds a preimage with the time complexity of 2n. It is converted to a preimage attack on the hash function with the time complexity of O(23n/2). As far as we know, any cryptanalytic result for MJH has not been published before. Our results are helpful for understanding the security of the hash modes together with their security proofs.

  • Determining the Optimum Font Size for Braille on Capsule Paper

    Tetsuya WATANABE  

     
    LETTER-Rehabilitation Engineering and Assistive Technology

      Vol:
    E97-D No:8
      Page(s):
    2191-2194

    Braille fonts allow us to easily make braille labels on capsule paper. For legibility, fonts should be printed at optimum sizes. To find the optimum sizes for Japanese braille fonts, we conducted an experiment in which a Japanese braille font was printed at various sizes on capsule paper and read and rated by young braille users. The results show that braille printed at 17 and 18 point sizes were read faster and evaluated higher than those printed at smaller or bigger sizes.

  • Tree Fusion Method for Semantic Concept Detection in Images

    Jafar MANSOURI  Morteza KHADEMI  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E97-D No:8
      Page(s):
    2209-2211

    A novel fusion method for semantic concept detection in images, called tree fusion, is proposed. Various kinds of features are given to different classifiers. Then, according to the importance of features and effectiveness of classifiers, the results of feature-classifier pairs are ranked and fused using C4.5 algorithm. Experimental results conducted on the MSRC and PASCAL VOC 2007 datasets have demonstrated the effectiveness of the proposed method over the traditional fusion methods.

  • Functional Safety Assessment of Safety-Related Systems with Non-perfect Proof-Tests

    Hitoshi MUTA  Yoshinobu SATO  

     
    PAPER-Reliability, Maintainability and Safety Analysis

      Vol:
    E97-A No:8
      Page(s):
    1739-1746

    The second edition of the international standard of IEC 61508, functional safety of electrical/electronic/programmable electronic safety-related system (SRS), was published in 2010. This international standard adopts a risk-based approach by which safety integrity requirements can be determined. It presents a formula to estimate the hazardous event rate taking account of non-perfect proof-tests. But it is not clear how to derive the formula. In the present paper, firstly, taking account of non-perfect proof-tests, the relationship between the dangerous undetected failure of SRS, the demand on the SRS and hazardous event is modeled by a fault tree and state-transition diagrams. Next, the hazardous event rate is formulated by use of the state-transition diagrams for the determination of the safety integrity requirements. Then, a comparison is made between the formulas obtained by this paper and given in the standard, and it is found that the latter does not always present rational formulation.

  • Tracking People with Active Cameras Using Variable Time-Step Decisions

    Alparslan YILDIZ  Noriko TAKEMURA  Maiya HORI  Yoshio IWAI  Kosuke SATO  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E97-D No:8
      Page(s):
    2124-2130

    In this study, we introduce a system for tracking multiple people using multiple active cameras. Our main objective is to surveille as many targets as possible, at any time, using a limited number of active cameras. In our context, an active camera is a statically located pan-tilt-zoom camera. In this research, we aim to optimize the camera configuration to achieve maximum coverage of the targets. We first devise a method for efficient tracking and estimation of target locations in the environment. Our tracking method is able to track an unknown number of targets and easily estimate multiple future time-steps, which is a requirement for active cameras. Next, we present an optimization of camera configuration with variable time-step that is optimal given the estimated object likelihoods for multiple future frames. We confirmed our results using simulation and real videos, and show that without introducing any significant computational complexities, it is possible to use active cameras to the point that we can track and observe multiple targets very effectively.

  • Effects of Conversational Agents on Activation of Communication in Thought-Evoking Multi-Party Dialogues

    Kohji DOHSAKA  Ryota ASAI  Ryuichiro HIGASHINAKA  Yasuhiro MINAMI  Eisaku MAEDA  

     
    PAPER-Natural Language Processing

      Vol:
    E97-D No:8
      Page(s):
    2147-2156

    This paper presents an experimental study that analyzes how conversational agents activate human communication in thought-evoking multi-party dialogues between multi-users and multi-agents. A thought-evoking dialogue is a kind of interaction in which agents act to provoke user thinking, and it has the potential to activate multi-party interactions. This paper focuses on quiz-style multi-party dialogues between two users and two agents as an example of thought-evoking multi-party dialogues. The experimental results revealed that the presence of a peer agent significantly improved user satisfaction and increased the number of user utterances in quiz-style multi-party dialogues. We also found that agents' empathic expressions significantly improved user satisfaction, improved user ratings of the peer agent, and increased the number of user utterances. Our findings should be useful for activating multi-party communications in various applications such as pedagogical agents and community facilitators.

  • Design of A Wideband Filter With Attenuation Poles Using A Novel Parallel-Coupled Three-line Unit Based on Cross-Coupling

    Chun-Ping CHEN  Junya ODA  Tetsuo ANADA  

     
    PAPER

      Vol:
    E97-C No:7
      Page(s):
    689-696

    To implement a wideband bandpass filter with improved skirt-selectivity and out-band characteristics, a new parallel-coupled three-line unit with two short-circuited stubs symmetrically-loaded at the center line is proposed. Unlike most traditional ones, the passband of the proposed parallel-coupled three-line structure is based on the cross-coupling between non-adjacent lines rather than the direct-coupling between adjacent ones, whereas a pair of attenuation poles is found in the stopbands. After revealing its work mechanism, an efficient filter-design-scheme is correspondingly proposed for the presented structure. Firstly, based on a chebyshev-filter synthesis theory, a wideband passband filter consisting of a parallel-coupled two-line and two short-circuited stubs loaded at the input- and output- ports is designed. Furthermore, by putting a properly-designed 3/4-wavelength stepped-impedance resonator (SIR) in between the parallel-coupled two lines, two attenuation poles are then realized at the frequencies very close to the cutoff ones. Accordingly, the roll-off characteristics of the filter are significantly-improved to greater than 100,dB/GHz. Furthermore, two-section open-ended stubs are used to replace the short-circuited ones to realize a pair of extra attenuation poles in stopbands. To validate the proposed techniques, a wideband filter with a bandwidth of 3--5,GHz (Fractional bandwidth (FBW) $= (5,GHz-3,GHz)/4,GHz =50%)$ was designed, simulated, fabricated and measured. The measured responses of the filter agree well with the simulation and theoretical ones, which validates the effectiveness of the newly-proposed three-line unit and the corresponding design scheme.

  • A Study on Optimization of Waveguide Dispersion Property Using Function Expansion Based Topology Optimization Method

    Hiroyuki GOTO  Yasuhide TSUJI  Takashi YASUI  Koichi HIRAYAMA  

     
    PAPER

      Vol:
    E97-C No:7
      Page(s):
    670-676

    In this paper, the function expansion based topology optimization is employed to the automatic optimization of the waveguide dispersion property, and the optimum design of low-dispersion slow-light photonic crystal waveguides is demonstrated. In order to realize low-dispersion and large group index, an objective function to be optimized is expressed by the weighted sum of the objective functions for the desired group index and the low-dispersion property, and weighting coefficients are updated through the optimization process.

  • An Interference-Robust Channel Estimation Method for Transparent MU-MIMO Transmission in LTE-Advanced System

    Won-Jun HWANG  Jun-Hee JANG  Seong-Woo AHN  Hyung-Jin CHOI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E97-B No:7
      Page(s):
    1412-1421

    In LTE (Long Term Evolution)-Advanced system, a transparent MU-MIMO (Multi-User Multiple-Input Multiple Output) scheduling is basically considered, so the performance degradation in channel estimation may occur due to the unpredictable interference from co-scheduled layers. In order to detect and mitigate the interference, traditional binary hypothesis testing based interference detection method and iterative channel estimation method can be applied. However, there are two major problems. First, the binary hypothesis testing based interference detection is not suitable solution for LTE-Advanced system which has four dynamically changing interference hypotheses. Second, the conventional iterative operation does not guarantee sufficient performance gain with limited iteration time due to the estimation error in initial estimation stage. To overcome these problems, we introduce an enhanced iterative channel estimation method which considers simple matrix operation-based partial interference estimation. Based on the outcomes of the partial interference estimation, we can not only detect interference layers individually, but also partially eliminate the interference in initial channel estimation stage. Consequently, the proposed method can effectively mitigate the interference adaptively to the dynamically changing interference condition.

2261-2280hit(8214hit)