• Title/Summary/Keyword: Coherence Analysis

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Study of US/EU National Innovation Policies Based on Nanotechnology Development, and Implications for Korea

  • Lim, Jung Sun;Shin, Kwang Min;Yoon, Jin Seon;Bae, Seoung Hun
    • Journal of Information Science Theory and Practice
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    • v.3 no.1
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    • pp.50-65
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    • 2015
  • Recently US/EU governments are utilizing nanotechnology as a key catalyst to support national innovation policies with economic recovery goals. US/EU nano policies have been serving as a global model to various countries, including Korea. So the authors initially seek to understand US/EU national innovation policy interconnections, and then find the role of nanotechnology development within. To strengthen national policy coherence, nanotechnology development strategies are under evolution as an innovation catalyst for promoting commercialization. To strategically support nano commercialization, EHS (Environmental, Health, Safety) and informatics are invested as priority fields to strengthen social acceptance and sustainability of nano enabled products. The current study explores US/EU national innovation policies including nano commercialization, EHS, and Informatics. Then obtained results are utilized to analyze weaknesses of Korean innovation systems of connecting creative economy and nanotechnology development policies. Then ongoing improvements are summarized focusing on EHS and informatics, which are currently prominent issues in international nanotechnology development.

A Study on eTextbook Development for Mobile Learning in a University (대학에서의 모바일 러닝을 위한 전자교재 개발 사례 연구)

  • Jung, Hyojung;Chon, Eunhwa;Suh, Eung-Kyo
    • Journal of Information Technology Services
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    • v.14 no.4
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    • pp.237-256
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    • 2015
  • The purpose of this study is to develop the eTextbook and to explore the usability of the eTextbook for accelerating mobile learning in university. This study was primarily based on needs analysis of students, and eTextbook was created based on digital publishing through Adobe DPS. The major design principles of the eTextbook based on previous studies were as follow. First, eTextbook should deliver learning contents in a simple and systematic way. Second, eTextbook should induce student's flows by providing segmented learning contents and various learning resources. Third, eTextbook should expand information accessibility by providing a wide variety of multimedia functions. The development principles of eTextbook have been developed based on cognitive psychology. Location and function of the link or icon used for eTextbook have been developed on the basis of the principles of cognitive psychology. The main development principles were Coherence, Signaling, Redundancy, Segmentation, Multimedia principle, and so on. In order to examine usability of the developed eTextbook, experts' and learners' reactions were evaluated. The primary responses of learners are that the eTextbook increased the learning accessibility and provided various multimedia factors, and thus increased the learning flows in the class.

Running Monitoring by the Noise and Vibration Measurement near the Wheelset of the High-Speed Trains : A Preliminary Research (고속철도차량 윤축부근의 소음과 진동 측정을 통한 주행중 감시의 기초연구)

  • Lee, Jun-Seok;Choi, Sung-Hoon;Park, Choon-Soo
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.1454-1462
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    • 2008
  • This paper is focused on the analysis of the noise and vibration measured near the wheelset of the high-speed trains using a time-varying frequency transform as a preliminary research of running monitoring. Due to the non-stationary characteristics, it is necessary to examine noise and vibration of the train with time-varying frequency transforms. In this paper, the short-time Fourier transform method is utilized - the stored data is localized by modulating with a window function, and Fourier transform is taken to each localized data. For the examination, the non-stationary noise and vibration of the high-speed train's wheelset are measured by using some microphones and accelerometers, and those signals are stored in a on-board data acquisition system. The non-stationary random signal analyses with the short-time Fourier transform are performed, and the result are classified as follows; auto-spectral density, cross-spectral density, frequency response, and coherence functions. From those functions, it is possible to observe the frequency characteristics of sleepers, switchers, tunnels, and steel bridges. Also, some distinct peaks, which are not dependent upon the train's speed, are identified from the results.

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Cross-Correlation of Oscillations in A Fragmented Sunspot

  • Lee, Kyeore;Chae, Jongchul
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.45.3-46
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    • 2018
  • Oscillations in a sunspot are easily detected through the Doppler velocity observation. Although the sunspot oscillations look erratic, the wavelet analysis show that they consist of successive wave packets which have strong power near three or five minutes. Previous studies found that 3-min oscillation at the chromosphere is a visual pattern of upward propagating acoustic waves along the magnetic field lines. Resent multi-height observations help this like vertical study, however, we also focus on horizontal facet to extend three dimensional understand of sunspot waves. So, we investigate a fragmented sunspot expected to have complex wave profiles according to the positions in the sunspot observed by the Fast Imaging Solar Spectrograph. We choose 4 points at different umbral cores as sampling positions to determine coherence of oscillations. The sets of cross-correlation with three and five minutes bandpass filters during a single wave packet reveal interesting results. Na I line show weak correlations with some lags, but Fe I and Ni I have strong correlations with no phase difference over the sunspots. It is more remarkable at Ni I line with 3-min bandpass that all sets of cross-correlation look like the autocorrelation. We can interpret this as sunspot oscillations occur spontaneously over a sunspot at photosphere but not at chromosphere. It implies a larger or deeper origin of 3-min sunspot oscillation.

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Autism Spectrum Disorder and Savant Syndrome: A Systematic Literature Review

  • Hyun Ok Park
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.34 no.2
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    • pp.76-92
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    • 2023
  • Objectives: This study aimed to analyze research trends in autism spectrum disorder (ASD) and savant syndrome and their cognitive characteristics through a systematic literature review. The objectives of this study were to establish an overview of research trends in ASD and savant syndrome, analyze the overall characteristics of individuals with ASD and savant syndrome, and examine their cognitive characteristics. Methods: For the systematic literature review, three criteria were used to select review articles: 1) literature from peer-reviewed journals, published in the past 15 years, from 2008 to 2022; 2) subjects with ASD and savant syndrome; 3) study objectives focused on the basic phenomenon and cognitive characteristics of ASD and savant syndrome. Finally, based on the selection criteria, a total of 40 articles were included. Results: Five themes and nine subthemes were derived from the analysis of 40 studies. The five main themes were as follows: 1) What is savant syndrome? 2) Demographic characteristics of savant syndrome; 3) Spectra of savant syndrome; 4) Savant syndrome and ASD; and 5) Cognitive characteristics of ASD with savant syndrome. The subthemes of the cognitive characteristics were weak central coherence, detail-focused cognitive processing, enhanced perceptual functioning, and hyper-systemizing. Conclusion: Several studies have been conducted to understand ASD and savant syndrome; however, no single theory can specify the cognitive characteristics of people with ASD and savant syndrome. Therefore, further systematic and multi-layered research on ASD and savant syndrome are required for more comprehensive results.

Wideband OFDM Communication Performance Analysis in the East Sea of Korea (대한민국 동해 해역에서 광대역 OFDM 통신 성능 분석)

  • Kwang-Young Chae;Zhao Tzan Chi;Meng Fan Jin;Min-Hyuk Cha;Ho-Jun Lee;Hak-Lim Ko;Tae-Ho Im
    • Proceedings of the Korea Information Processing Society Conference
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    • 2023.11a
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    • pp.1234-1236
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    • 2023
  • 광대역(Wideband) 통신은 신호 대역폭이 채널의 상관 대역폭(Coherence Bandwidth)를 크게 초과하는 시스템을 나타낸다. 이때, 큰 대역폭을 갖을수록 반송 주파수대역과 사용대역의 최대 및 최소 주파수 간 차이가 커지며, 통신 시스템이 겪는 채널의 주파수 선택적 페이딩 또한 커지게 된다. 수중에서 광대역 통신을 성능을 확인하기 위한 실험을 수행하였다. 실험환경으로는 송·수신기 간 수평 이격거리는 약 10m, 수직 이격거리는 약 190m로 설정하였다. 광대역 신호의 성능을 확인하기 위하여 14kHz와 30kHz의 주파수 대역과 협대역신호와의 비교를 위해 16kHz와 4kHz 대역폭 등 파라메타를 달리하여 설정하였다. x축을 Repetition Freq.와 Repetition Time의 조합으로 설정하였으며, y축을 BER(Bit Error Rate)로 성능결과를 나타내었다.

An Analysis of the Vibration Characteristics through the Human Body (인체 내부에서의 진동 전달특성 분석)

  • 전종원;진용옥
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.7
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    • pp.59-65
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    • 2000
  • This paper describes the analysis of vibration characteristics through the human body as the research for voice therapy and diagnosis. The oscillation signal is not external forces but the self-voice to be pronounced the vowels ('a', 'e', 'i', 'o', 'u'). The experiment system consists of microphones, accelerometers and amplifiers. The input data are stored by the computer. At the same time, the voice is stored by the microphone and the vibration signal of the human body is stored by accelerometer. The 63 points are appointed in head, neck, trunk of human body. The positions and number of times are changeable by the purpose. The analysis parameters are amplitude, phase, fundamental. frequency, formant and the correlation of vibration signal and voice is measured by coherence function. The results show that the vibration signals have characteristic vibration in the positions of human body.

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Experimental contribution analysis of external aeroacoustic noise sources to interior noise of automobile (자동차 외부 공기음향 소음원들의 실험적 실내 기여도 분석 기술 개발)

  • Lee, Myung Han;Ih, Kang Duck;Hwang, Seongil;Kim, Yong-Joe
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.5
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    • pp.300-308
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    • 2018
  • The contribution analysis of various external aeroacoustic noise sources to interior noise is important, enabling to design an automobile with a low interior noise level. With a new technique, the CD (Cholesky Decomposition), it is proposed to decompose an overall interior noise spectrum into multiple spectra, each representing the contribution of a specific noise source to the interior noise. In order to validate this method, three kinds of experiments were conducted. Furthermore, it is proposed to improve the CD-based contribution analysis method to be integrated with existing exterior microphone arrays in the wind tunnel. This method was validated with an experiment with two speakers.

Comparison of the Spiritual Needs of Terminal Cancer Patients and Their Primary Family Caregivers

  • Kang, Kyung-Ah;Choi, Youngsim
    • Journal of Hospice and Palliative Care
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    • v.23 no.2
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    • pp.55-70
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    • 2020
  • Purpose: This study was conducted to examine differences in Spiritual Interests Related to Illness Tool (SpIRIT) scores and the degree of spiritual needs (SNs) between patients with terminal cancer and their primary family caregivers and to compare spiritual needs between them. Methods: The study participants were inpatients with terminal cancer and their primary family caregivers at 40 national hospice centers. The final analysis included 120 SpIRIT surveys from patients and 115 from family members, and 99 SNs questionnaires from patients and 111 from family members. Data analysis was conducted using descriptive statistics, the t-test, one-way analysis of variance, and Pearson correlation coefficients. Results: There were no significant between-group differences in SpIRIT scores or SNs. The SpIRIT sub-dimensions that ranked high for both patients and primary family caregivers were "maintaining positive perspective", "loving others", and "finding meaning". The SNs sub-dimensions were ranked identically in both groups, in the order of "love and connection", "hope and peace", "meaning and purpose", respectively. In both groups, the recognition of the importance of spiritual matters and religion were major factors influencing SpIRIT scores and SNs. Conclusion: The SpIRIT scores and degree of SNs of patients with terminal cancer and their primary family caregivers were found to be very closely related, and the needs for coherence and meaning were greater than religious needs. When providing spiritual care for patients with terminal illness, family members should also be considered, and their prioritization of spiritual needs and the importance of spiritual matters and religion shall be taken into account.

Neutron Noise Analysis for PWR Core Motion Monitoring (중성자 잡음해석에 의한 PWR 노심 운동상태 감시)

  • Yun, Won-Young;Koh, Byung-Jun;Park, In-Yong;No, Hee-Cheon
    • Nuclear Engineering and Technology
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    • v.20 no.4
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    • pp.253-264
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    • 1988
  • Our experience of neutron noise analysis in French-type 900 MWe pressurized water reactor (PWR) is presented. Neutron noise analysis is based on the technique of interpreting the signal fluctuations of ex-core detectors caused by core reactivity changes and neutron attenuation due to lateral core motion. It also provides advantages over deterministic dynamic-testing techniques because existing plant instrumentation can be utilized and normal operation of the plant is not disturbed. The data of this paper were obtained in the ULJIN unit 1 reactor during the start-up test period and the statistical descriptors, useful for our purpose, are power spectral density (PSD), coherence function (CF), and phase difference between detectors. It is found that core support barrel (CSB) motions induced by coolant flow forces and pressure pulsations in a reactor vessel were indentified around 8 Hz of frequency.

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