• Earthquakes and Structures
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• 제10권1호
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• pp.239-260
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• 2016

Tuned mass dampers (TMDs) have been frequently proposed to mitigate the detrimental effects of dynamic loadings in structural systems. The effectiveness of this protection strategy has been demonstrated for wind-induced vibrations and, to some extent, for seismic loadings. Within this framework, recent numerical studies have shown that beneficial effects can be achieved by placing a linear TMD on the roof of linear elastic structural systems subjected to pulse-like ground motions. Motivated by these positive outcomes, closed-form design formulations have been also proposed to optimize the device's parameters. For structural systems that undergo a near-fault pulse-like ground motion, however, it is unlikely that their dynamic response be linear elastic. Hence, it is very important to understand whether such strategy is effective for inelastic structural systems. In order to provide new useful insights about this issue, the paper presents statistical results obtained from a numerical study conducted for three shear-type hysteretic (softening-type) systems having 4, 8 and 16 stories equipped with a linear elastic TMD. The effectiveness of two design procedures is discussed by examining the performances of the protected systems subjected to 124 natural pulse-like earthquakes.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4715-4721
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• 2022

A comprehensive approach for modeling the pulse height spectra of gamma-ray detectors from passing radioactive cloud in a case of accident at NPP has been developed. It involves modeling the transport of radionuclides in the atmosphere using Lagrangian stochastic model, WRF meteorological processor with an ARW core and GFS data to obtain spatial distribution of radionuclides in the air at a given moment of time. Applying representation of the cloud as superposition of elementary sources of gamma radiation the pulse height spectra are calculated based on data on flux density from point isotropic sources and detector response function. The proposed approach allows us to obtain time-dependent spectra for any complex radionuclide composition of the release. The results of modeling the pulse height spectra of the scintillator detector NaI(Tl) Ø63×63 mm for a hypothetical severe accident at a NPP are presented.

• 대한한방부인과학회지
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• 제26권1호
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• pp.82-91
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• 2013

Objectives: The purpose of this study is to find out the patterns of teenage girls who is easy to suffer from Menstrual Disorders. Methods: The data from the 1681 participants were collected using a structured menstrual history questionnaire. Based on the survey responses, we had 97 adolescents with menstrual disorder as the test group and 97 adolescents without menstrual disorder as the control group. The clinical trials subjects were asked to respond to another questionnaire for identifying Blood Pressure Pulse Analyzer tests. We identified significant variables for dysmenorrhea from comparison between the test and control group; a binary response variable from the test group's responses for ever experiencing dysmenorrhea and explanatory variables from Blood Pressure Pulse Analyzer. Results: The reselts of Blood Pressure Pulse Analyzer test showed that the score of Energ_R, EIX_R were lower in dysmenorrhea group than the control group. The reselts of Blood Pressure Pulse Analyzer test showed that the score of Energ_R, EIX_R were lower, and T4_R were higher in hypomenorrhea group than the control group. The reselts of Blood Pressure Pulse Analyzer test showed that the score of Energ_R, EIX_R were lower in Irregular Menstruation group than the control group. Conclusions: Blood Pressure Pulse Analyzer test showed that the score of Energ_R, EIX_R were lower in the test group than the control group.

• 대한임상전기생리학회지
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• 제7권1호
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• pp.7-10
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• 2009

Purpose : The purpose of this study was to investigate the effect of electrical stimulation applied in dominant forearm on autonomic nervous system response of both hands. Methods : Fourteen healthy subjects (women) received low frequency-high intensity electrical stimulation to one forearm. The subjects assigned to two groups; a ipsilateral stimulation group (n=7) and a contralateral stimulation group (n=7). The electrode attachment was arranged on the forearm of the dominant arm and the electricity stimulus time was set as 15 minutes. Measuring items were the skin conduction velocity, the blood flow, and the pulse rate, which were measured total 3 times (pre, post, and post 10 min.). Results : The skin conduction velocity showed a significant difference according to the change of the time in both hands, but there was no significant difference according to time in the blood flow, and the change of the pulse frequency regardless of stimulus side. Conclusion : These results demonstrate that the low frequency-high intensity electrical stimulation applied dominant forearm can increase selectively only with the skin conduction velocity, which may be helpful for the activation of the sudomotor function of both hands by the activation of sympathetic nerve.

• Earthquakes and Structures
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• 제15권3호
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• pp.243-251
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• 2018

The dynamic responses of a rocking wall-moment frame (RWMF) with a post-tensioned cable are investigated. The nonlinear equations of motions are developed, which can be categorized as a single-degree-of-freedom (SDOF) model. The model is validated through comparison of the rocking response of the rigid rocking wall (RRW) and displacement of the moment frame (MF) against that obtained from Finite Element analysis when subjected ground motion excitation. A comprehensive parametric analysis is carried out to determine the seismic performance factors of the RWMF systems under near-fault trigonometric pulse excitation. The horizontal displacement of the RWMF system is compared with that of MF structures without RRW, revealing the damping effect of the RRW. Frame displacement spectra excited by trigonometric pulses and recorded earthquake ground motions are constructed. The effects of pulse type, mass ratio, frame stiffness, and wall slenderness variations on the displacement spectra are presented. The paper shows that the coupling with a RRW has mixed results on suppressing the maximum displacement response of the frame.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.23-28
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• 2007

In most existing research, it is difficult to evaluate thermal comfort exactly because of reflecting individual ideal or psychological response by subjective questions. Physiological variable was selected in this study to evaluate objectively thermal comfort. MST was appeared very sensitively in indoor temperature and can express correctly thermal comfort of human body. The results of CSV are different each individual feeling sensation, so is difficult to evaluate detailedly thermal comfort unlike TSV. But the results of PP, AIx, ED, SEVR are greatly related to temperature change. So thermal comfort is evaluated more objectively by using PP, AIx, ED, SEVR on behalf of TSV, CSV. Human body was presented physiological feedback by temperature impetus and specially, tendency of heart rate agree with temperature change. Physiological reaction was showed sufficient possibility availing evaluation index of thermal comfort. In the future another one needs to review beside the selected physiological variable.

• 한국통신학회논문지
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• 제28권12A호
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• pp.983-990
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• 2003

본 논문에서는 3GPP 모뎀용 비동기식 동기추적회로(noncoherent code tracking loop)를 설계하고 설계된 회로의 정상상태 지터 분산(steady-state jitter variance)과 과도응답 특성(transient response characterisitc)을 해석한다. 먼저, AWGN 환경에서의 지터 분산을 펄스성형 필터(pulse-shaping filter), 타이밍 오프셋(timing offset), 신호 대잡음비(signal-to-interference ratio), 루우프 대역폭(loop bandwidth)에 대한 일반식으로 유도하고, 과도응답 특성을 이론적으로 해석한다. 이를 바탕으로, 디지털 하드웨어 구현이 용이한 가변 대역폭 동기추적회로를 설계하며 설계된 회로와 고정 대역폭 시스템의 성능을 이론적으로 비교, 분석하고 컴퓨터 시뮬레이션을 통해 검증한다.

• Steel and Composite Structures
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• 제29권5호
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• pp.569-578
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• 2018

This paper aims to investigate the transient vibration behavior of functionally graded carbon nanotube (FG-CNT) reinforced nanocomposite plate resting on Pasternak foundation under pulse excitation. The plate is considered to be composed of matrix material and multi-walled carbon nanotubes (MWCNTs) with distribution as per the functional grading concept. The functionally graded distribution patterns in nanocomposite plate are explained more appropriately with the layer-wise variation of carbon nanotubes weight fraction in the thickness coordinate. The layers are stacked up in such a way that it yields uniform and three other types of distribution patterns. The effective material properties of each layer in nanocomposite plate are obtained by modified Halpin-Tsai model and rule of mixtures. The governing equations of an illustrative case of simply-supported nanocomposite plate resting on the Pasternak foundation are derived from third order shear deformation theory and Navier's solution technique. A converge transient response of nanocompiste plate under uniformly distributed load with triangular pulse is obtained by varying number of layer in thickness direction. The validity and accuracy of the present model is also checked by comparing the results with those available in literature for isotropic case. Then, numerical examples are presented to highlight the effects of distribution patterns, foundation stiffness, carbon nanotube parameters and plate aspect ratio on the central deflection response. The results are extended with the consideration of proportional damping in the system and found that nanocomposite plate with distribution III have minimum settling time as compared to the other distributions.

• 대한한의진단학회지
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• 제19권2호
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• pp.75-90
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• 2015

Objectives The purposes of this study was to develope a Qi gong exercise that suits characteristics of post mastectomy women, and to evaluate the effect of Qi gong exercise on immune response, blood circulation index, pulse wave parameter and heart rate variability. Methods This study was applied to total 35 post mastectomy women, including 17 for experiment group and 18 for control group. The Qi gong exercise was composed of total 24 times of 90 minutes per each time, twice a week, and 12 weeks and it was conducted by the oriental medicine professor who was an expert of Qi gong exercise. Results 1. Two group comparison revealed that the experimental group had significantly improved immune response(p<.021), HR(beats/min)(p<.001), ESV(ml/beat)(p=.038), ESI($ml/beat/m^2$)(p=.040), ECO (L/min)(p=.019), ECI($L/min/m^2$)(p=.023), ECRI($dyne^*sec/cm$)(p=.015), Left Kwan($div^3$)(p=.021), Right Kwan($div^3$)(p=.038), Mean HRV(cycle/min)(p<.001), SDNN(ms)(p=.043), RMSSD(ms)(p=.040), and TP(log $ms^2$)(p=.039). 2. Two group comparison revealed that the experimental group had significantly decreased ECR ($dyne^*sec^*cm^{-5}$) (p=.034), Left RAI(p=.044), Right RAI(p=.042), and pNN50(%)(p=.038). Conclusions These results from Qi gong exercise program can be used as basic data for development of health promotion program for Post Mastectomy Women.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.269-273
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• 1999

Combination of mental stress task with noise background is a traditional tool employed in psychophysiology. However, intensity of background noise is a factor affecting both performance on test and psychophysiological responses associated with stress evoked by mental load in noisy environment. In the current study on 7 subjects we analyzed the influence of white noise (WN) intensity (55, 70, and 85 dB[A] ) on psychophysiological responses during word recognition test performed on noise background. There were recorded following physiological variables: electrodermal activity (EDA) , namely, skin conductance level (SCL), skin conductance response (SCR) amplitude (SCR-A), rise time and total number of SCRs (N-SCR); cardiovascular activity, e.g., heart rate (HR), respiratory sinus arrhythmia (RSA) index, pulse transit time (PTT), finger pulse volume (PV), skin temperature (SKT) and respiratory activity, such as respiration rate (RESP-R) and inspiration wane amplitude (RESP-A) during baseline resting state and 40 s long performance on 3 similar Korean word recognition tests with different WN intensity (55, 70, and 85 dB). Electrodermal responses (SCR-A, SCL, N-SCR) demonstrated gradual increment with increased intensity of noise, and this increase of response magnitude with higher intensity of noise was typical also for r skin temperature (phasic SKT decrease) and pulse volume (phasic and tonic PV decrease). However, some cardiovascular and respiratory responses did not exhibit same tendency of gradual increase of reactivity , namely HR, as well as RESP-R and RESP-A showed decrement of response magnitudes. Important finding in terms of cardiovascular reactivity was that 55 and 70dB evoked similar profiles, while 85dB WN resulted in significantly different profile of reactions, suggesting that there exists a threshold level after which intensive auditory stimulation elicits psychophyslological responses pattern of different quality. There are discussed potential autonomic mechanism involved in mediation of observed physiological responses.