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Development of a Hearing Impairment Simulator considering Frequency Selectivity of the Hearing Impaired (난청인의 주파수 선택도를 고려한 난청 시뮬레이터 개발)

  • Joo, S.I.;Kil, S.K.;Goh, M.S.;Lee, S.M.
    • Journal of Biomedical Engineering Research
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    • v.30 no.1
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    • pp.94-102
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    • 2009
  • In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity of the hearing impaired, and verify it's performance through experiments. The reduced frequency selectivity was embodied by spectral smearing using linear prediction coding(LPC). The experiments are composed of 4 kinds of tests; pure tone test, speech reception threshold(SRT) test, and word recognition score(WRS) test without spectral smearing and with spectral smearing. The experiments of the hearing impairment simulator were performed with 9 subjects who have normal hearing. The amount of spectral smearing was controlled by LPC order. The percentile score of WRS test without smearing is $89.78{\pm}2.420%$. The scores of WRS with 24th LPC order and with 8th LPC order are $88.00{\pm}3.556%$ and $83.78{\pm}2.123%$ respectively. It is verified that WRS score is lowered by decreasing LPC order. This is a reasonable result considering that spectral smearing is getting heavier according to decreasing LPC order. It is confirmed that spectral smearing using LPC simulates the reduced frequency selectivity of the hearing impaired and affects the clearness of speech reception.

A Photometric Investigation of KIC6118779 with Phase Smearing Effect

  • Jeong, Min-ji;Kim, Chun-Hwey
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.63.3-64
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    • 2017
  • KIC6118779 is an over-contact binary system having a short orbital period of about 0.36 days. The photometric data for this system are acquired by the observations of Kepler mission in the long cadence mode having a time resolution of about 30 minutes. It means that the Kepler light curves of the system may be strongly affected by phase smearing effect and the analysis of them without consideration of the phase smearing effect may result in wrong stellar properties. Additionally, this system also shows dynamical variation of light curve resulting from spot activity. For all those reasons, it is difficult to investigate KIC6118779, and the investigation should be carried out carefully. In this presentation, we introduce the phase smearing effect and carry out the light curve modeling with the 2015 version of the Wilson-Devinney binary code considering the phase smearing effect. Our results show that the system is a deep over contact binary system and has extremely low mass ratio of about 0.12. Moreover our spot modeling implies the cyclic migration of a big cool spot on the massive component.

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Influence of the Galactic Magnetic Field on the Distribution of Ultra-high-Energy Cosmic Rays

  • Kim, Jihyun;Kim, Hang Bae;Ryu, Dongsu
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.38.3-38.3
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    • 2015
  • Recently, the Pierre Auger Observatory (PAO), the largest ground-based project for detecting ultra-high-energy cosmic rays (UHECRs), published their 10-year data. We can access an unprecedented number of UHECR data observed by the project, which give us a possibility to get an accurate statistical test result. In this work, we investigate the influence of the galactic magnetic field (GMF) on the distribution of UHECRs by searching the correlation with the large-scale structure (LSS) of the universe. We simulate the mock UHECR events whose trajectories from the sources would be deflected by the Gaussian smearing angle which reflects the influence by the GMF. By the statistical test, we compare the correlation between the expected/observed distribution of UHECRs and the LSS of the universe in the regions of sky divided by the galactic latitude, varying the smearing angle. Here, we assume the deflections by the GMF are mainly dependent on the galactic latitude. Using the maximum likelihood estimation, we find the best-fit smearing angle in each region. If we get a trend that best-fit smearing angles differ from each region, the influence of GMF may be stronger than that of intergalactic magnetic fields (IGMF) because it is known that the distribution of IGMF follows the LSS of the universe. Also, we can estimate the strength of the GMF using the best-fit parameter by the maximum likelihood.

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Estimation of Prediction Values in ARMA Models via the Transformation and Back-Transformation Method (변환-역변환을 통한 자기회귀이동평균모형에서의 예측값 추정)

  • Yeo, In-Kwon;Cho, Hye-Min
    • The Korean Journal of Applied Statistics
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    • v.21 no.3
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    • pp.537-546
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    • 2008
  • One of main goals of time series analysis is to estimate prediction of future values. In this paper, we investigate the bias problem when the transformation and back- transformation approach is applied in ARMA models and introduce a modified smearing estimation to reduce the bias. An empirical study on the returns of KOSDAQ index via Yeo-Johnson transformation was executed to compare the performance of existing methods and proposed methods and showed that proposed approaches provide a bias-reduced estimation of the prediction value.

A Method to Suppress False Alarms of Sentinel-1 to Improve Ship Detection

  • Bae, Jeongju;Yang, Chan-Su
    • Korean Journal of Remote Sensing
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    • v.36 no.4
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    • pp.535-544
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    • 2020
  • In synthetic aperture radar (SAR) based ship detection application, false alarms frequently occur due to various noises caused by the radar imaging process. Among them, radio frequency interference (RFI) and azimuth smearing produce substantial false alarms; the latter also yields longer length estimation of ships than the true length. These two noises are prominent at cross-polarization and relatively weak at co-polarization. However, in general, the cross-polarization data are suitable for ship detection, because the radar backscatter from background sea surface is much less in comparison with the co-polarization backscatter, i.e., higher ship-sea image contrast. In order to improve the ship detection accuracy further, the RFI and azimuth smearing need to be mitigated. In the present letter, Sentinel-1 VV- and VH-polarization intensity data are used to show a novel technique of removing these noises. In this method, median image intensities of noises and background sea surface are calculated to yield arithmetic tendency. A band-math formula is then designed to replace the intensities of noise pixels in VH-polarization with adjusted VV-polarization intensity pixels that are less affected by the noises. To verify the proposed method, the adaptive threshold method (ATM) with a sliding window was used for ship detection, and the results showed that the 74.39% of RFI false alarms are removed and 92.27% false alarms of azimuth smearing are removed.

Recognition of Passports using CDM Masking and ART2-based Hybrid Network

  • Kim, Kwang-Baek;Cho, Jae-Hyun;Woo, Young-Woon
    • Journal of information and communication convergence engineering
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    • v.6 no.2
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    • pp.213-217
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    • 2008
  • This paper proposes a novel method for the recognition of passports based on the CDM(Conditional Dilation Morphology) masking and the ART2-based RBF neural networks. For the extraction of individual codes for recognizing, this paper targets code sequence blocks including individual codes by applying Sobel masking, horizontal smearing and a contour tracking algorithm on the passport image. Individual codes are recovered and extracted from the binarized areas by applying CDM masking and vertical smearing. This paper also proposes an ART2-based hybrid network that adapts the ART2 network for the middle layer. This network is applied to the recognition of individual codes. The experiment results showed that the proposed method has superior in performance in the recognition of passport.

A planning of Sweeping Path for a Smearing Robot (자동 미장 로봇을 스위핑 경로 계획)

  • Hyun, Woong-Keun;Park, Sang-Kyoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.1
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    • pp.1187-1195
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    • 2001
  • This paper presents a sweeping path planning algorithm for an autonomous smearing robot. An automatic planner generates a sweeping path pattern by proposed five basic procedures. This algorithm rocog-nizes obstacle on the architectural CAD draft and generates subgoals as tracking points which executes the area filling task based on heuristic approach. A sweeping path is planned by sequentially connecting the track-ing points in such a way that(1) the connected line segments should not be crossed, (2) the total tracking points should be as short as possible, and (3) the tracking line should not pass through the obstacle, Feasibility of the developed techniques has been demonstrated on a real architectural CAD draft.

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A Study on Development of a Hearing Impairment Simulator considering Frequency Selectivity and Asymmetrical Auditory Filter of the Hearing Impaired (난청인의 주파수 선택도와 비대칭적 청각 필터를 고려한 난청 시뮬레이터 개발에 관한 연구)

  • Joo, Sang-Ick;Kang, Hyun-Deok;Song, Young-Rok;Lee, Sang-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.4
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    • pp.831-840
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    • 2010
  • In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity and asymmetrical auditory filter of the hearing impaired, and we verified the reduced frequency selectivity and asymmetrical auditory filter affected in speech perception through experiments. The reduced frequency selectivity has made embodied by spectral smearing using LPC(linear prediction coding). The shapes of auditory filter are asymmetrical different with each center frequency. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. The experiments confirmed subjective test and objective test. The subjective experiments are composed of 4 kinds of tests: pure tone test, SRT(speech reception threshold) test, and WRS(word recognition score) test without spectral smearing, and WRS test with spectral smearing. The experiment of the hearing impairment simulator was performed from 9 subjects who have normal ears. The amount of spectral smearing was controlled by LPC order. The asymmetrical auditory filter of proposed hearing impairment simulator was simulated and then some tests to estimate the filter's performance objectively were performed. The objective experiment as simulated auditory filter's performance evaluation method used PESQ(perceptual evaluation of speech quality) and LLR(log likelihood ratio) for speech through auditory filter. The processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference according to asymmetrical auditory filter in hearing impairment simulator.