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Anyang, South Korea

Bae S.,Daelim University College | Kim M.,Soongsil University | Bae M.,Soongsil University
International Conference on ICT Convergence | Year: 2013

In speech or audio processing, coding may be define as a digital representation of signal that provides efficient storage, transmission, recovery, and perceptually faithful reconstruction of the original signal. In the coding methods, the waveform coding method can maintain the high quality and intelligibility, but the major drawback of this method is large amount of data required. Therefore, we proposed a waveform coding method using the non-uniform sampling and variables low pass filter of speech or audio signals. Simulation results show that this algorithm is robust in noisy environments. © 2013 IEEE. Source

Kim H.S.,Kyonggi University | Cho Y.M.,Seoul National University | Moon J.H.,Daelim University College
Smart Materials and Structures | Year: 2010

In this paper, we present an active vibration control system which is constructed based on a novel three-degrees-of-freedom(DOF) precision micro-stage. Unlike the traditional tripod systems, the proposed micro-stage is established to guarantee the compactness (60mm(h) × 160mm(d)) and the simplicity of its structure as well as the appropriate vertical/horizontal stiffness and the repeatability, which are essential in achieving the accuracy of sub-micrometers. First, combined with a finite element method(FEM), a physical model for the proposed micro-stage is constructed and its physical parameters, such as stiffness and damping coefficients, are estimated to predict the experimental results with high fidelity. In order to overcome the dynamic variations naturally stemming from the payload as well as the parameter uncertainties, a robust control system is then proposed to efficiently mitigate the vibration with a scale of sub-micrometers. Compared to the conventional control strategy, the proposed robust control scheme successfully establishes the active vibration control system and its performance is examined and validated through extensive experiments. © 2010 IOP Publishing Ltd. Source

Kim H.,Daelim University College | Lee H.-M.,Kyonggi University
Proceedings of 6th European Conference on Antennas and Propagation, EuCAP 2012 | Year: 2012

An integration of a wireless power transfer system is presented to obtain both high power transfer efficiency and a compact wireless power transfer structure. To have all these characteristics, transmitter and receiver parts suggested in previous researches are all integrated to new resonant coils fabricated on Teflon substrates. To verify this characteristic, an equivalent circuit model is presented. Using this basic theory, the optimized performance through EM simulations is predicted, and the proposed wireless power transfer is realized with a practical load. © 2012 IEEE. Source

Kwon S.,Daelim University College
Information Sciences | Year: 2014

This paper proposes an identity-based (ID-based) signature (IBS) scheme which is strongly unforgeable in the standard model whose security is reduced to the hardness of the computational Diffie-Hellman (CDH) problem in bilinear groups. Currently, the ID-based encryption scheme (IBE) due to Waters is known to be the most practically efficient IBE whose security is guaranteed in the standard model depending on the decisional bilinear Diffie-Hellman (BDH) assumption. While as a solution for an ID-based signature of a total ID-based public key cryptosystem cooperating with Waters IBE, we share Waters's construction and system parameters to keep a key pair corresponding to each identity unchanged, our IBS needs only one group element for signing of messages and two elements for its randomness as supplementary parameters plus the original system parameters. Accordingly, thanks to requiring about half the system parameters against previous ID-based signatures proved secure without using random oracles under the standard complexity assumptions like CDH or BDH, our IBS is the more suitable for storage and communication requirements. In particular, this covers a stronger security property called strong unforgeability in the standard model in itself without applying any transformation technique. © 2013 Elsevier Inc. All rights reserved. Source

Byeon H.,Daelim University College | Byeon H.,Ajou University | Lee Y.,Ajou University
Laryngoscope | Year: 2013

Objectives/Hypothesis: This study's objectives were to assess the prevalence rate of laryngeal pathologies in the Korean elderly, and to examine the association of smoking and alcohol consumption with laryngeal diseases. Study Design: Cross-sectional study. Methods: Data were from the 2008 Korea National Health and Nutritional Examination Survey. Subjects were 663 elderly persons (261 men and 402 women) between the ages of 65 and 84 years who completed the laryngoscopic examination. Weighted prevalence of laryngeal pathologies was compared by demographic characteristics, smoking, alcohol drinking, body mass index, and self-reported voice problems. Multiple logistic regression analyses were conducted to examine the independent as well as combined influence of smoking and alcohol consumption on laryngeal lesions. Results: The prevalence of laryngeal pathologies in the Korean elderly between the ages of 65 and 84 years was 8.1%. The prevalence of laryngeal lesions increased with age and was higher among men, middle school and high school graduates, manual workers, current smokers, current alcohol drinkers, and those with self-reported voice problems. Adjusting for covariates, current smokers, compared with nonsmokers, were more likely to have laryngeal pathologies (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.01-4.67). Current alcohol drinking was not independently associated with laryngeal diseases. Concurrent smoking and alcohol drinking, however, were associated with a significantly higher risk of laryngeal pathologies (OR, 3.29; 95% CI, 1.22-8.88). Conclusions: Smoking and alcohol consumption may increase the risk of laryngeal diseases in later life. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc. Source

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