• Sleep Medicine and Psychophysiology
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• v.3 no.1
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• pp.15-24
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• 1996

After rapid eye movement(REM) sleep was idenified in 1953, a lively interest developed concerning a possible role of this kind of sleep in memory processes. The author reviewed studies relating REM to memory/learning. Many studies in animals and humans gave substantial evidence for relating REM sleep to memory function. The evidence supporting the position taken in this paper comes from experiments showing that : (1) learning session is followed by the significant augmentation of REM sleep : (2) REM sleep deprivation, prior to learning or immediately thereafter, impairs the formation of a permanent memory/learning : (3) there is a vulnerable period of time(eg, REM sleep "window") following succussful learning, during which REM sleep deprivation results in memory impairment : (4) theta rhythm which develops during REM sleep induces long-term potentiation in hippocampus : (5) there are some evidences providing the relationship of neurotransmitter systems to the maintenance of REM sleep and memory storage processes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.113-119
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• 2019

This study aims at the analysis using the Resistivity Estimation Model (REM) to examine the effect of specimen size on the measurement of electrical resistivity. In the experiment, specimens of concrete were fabricated and the apparent resistivity was measured for each electrode interval. The apparent resistivity measured was found to be distorted in the apparent resistivity as the specimen size became smaller and closer to the outside (edge). As a result of comparing the experimental and analysis values, it is expected that REM can be used to examine the effect of the size of the specimen.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.196-202
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• 2006

The self diffusion distributions of viscoelastic molten polyurethanes were determined from the relationship between the relaxation spectra and the distribution of self diffusion. The relaxation spectra of ester, PCL and PCL dyed type molten polyurethanes were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Ree-Eyring and Maxwell non-Newtonian model(REM model) from computer calculation. The experiments were carried out at various temperatures using the physica rheometer with the temperature controller. The self diffusion and hole distance of amorphous region of polyurethane samples were investigated by experiments of stress relaxation. The diffusion coefficients and hole volumes were calculated from rheological parameters and crystallite size in order to study the diffusion of flow segments in amorphous region. It was observed that the relaxation spectra and self diffusions of these polymer samples are directly related to the distribution of molecular weights, viscosities, hole volumes and activation energies of flow segments.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.68-71
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• 2005

We report a case of obstructive sleep apnea syndrome, which occurred primarily during the REM sleep stage. A 55-year-old female patient who complained of chronic insomnia on the initial visit turned out to have obstructive sleep apnea syndrome of a mild degree (respiratory disturbance index (RDI) of 13.8/hour, %time spent below 90% of SaO2=5.0%) on nocturnal polysomnography. Interestingly, apnea episodes and desaturations mainly occurred during REM sleep stage. And RDI and destaturations during REM sleep stage were found to be severe enough to classify as a severe degree of obstructive sleep apnea syndrome. These findings suggest that severe obstructive sleep apnea syndrome might be masked under the symptom of chronic insomnia and that apneas can be predominantly localized within REM sleep epochs. In terms of treatment, "REM sleep-dependent" apneas may call for different methods of treatment, especially REM sleep-specific pharmacological intervention.

• Polymer(Korea)
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• v.37 no.2
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• pp.135-140
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• 2013

The stress relaxation of poly(methyl acrylate)-poly(acrylonitrile) copolymer samples was carried out in air, distilled water, pH 3, 7 and 11 solutions at various temperatures using a tensile tester equipped with a solvent chamber. The relaxation spectra of poly(methyl acrylate)-poly(acrylonitrile) copolymers were obtained by applying the experimental stress relaxation curves to the equation of relaxation spectrum derived from the Ree-Eyring and Maxwell model. The determination of relaxation spectra was performed from computer calculation using a Laplace transform method. It was observed that the relaxation spectra of these samples are directly related to the distribution of molecular weights and self-diffusions of flow segments.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.82-82
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• 2009

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.470-482
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• 1995

The Ulchin 3&4, which are 2825 MWt PWRs, adopted Safety Depressurization System (SDS) to mitigate the beyond design basis event of Total Less of Feedwater(TLOFW). In this study the results and methodology of the analyses for the determination of SDS bleed capacity are discussed. The SDS design bleed capacity has been determined from the CEFLASH-4AS/REM simulation according to the following design criteria : 1) Each SDS flow path, in conjunction with one of two High Pressure Safety Injection (HPSI) pumps, is designed to have a sufficient capacity to prevent core uncovery if one SDS path is opened simultaneously with the opening of the Pressurizer Safety Valves (PSVs). 2) Both SDS bleed paths are designed to have sufficient total capacity with both HPSI pumps operating to prevent core uncovery if the Feed and Bleed (F&B) initiation is delayed up to thirty minutes from the time of the PSVs lift. To verify the results of CEFLASH-4AS/REM simulation a comparative analysis kas also been per-formed by more sophisticated computer code, RELAP5/MOD3. The TLOFW event without operator recovery and TLOFW event with F&B are analyzed. The predictions by the CEFLASH-4AS/REM of the transient too phase system behavior are in good qualitative and quantitative agreement with those by the RELAP5/MOD3 simulation. Both of the results of analyses by CEFLASH-4AS/REM and RELAP5/MOD3 have demonstrated that decay heat removal and core inventory make-up can be successfully accomplished by F&B operation during now event for the Ulchin 3&4.

• Journal of IKEEE
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• v.27 no.4
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• pp.650-656
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• 2023

This paper implements a channel model for mmWave bands using an NS-3-based 5G system-level simulator and analyzes the reliability and validity of the implemented model through RF performance verification. The channel model for RF performance verification in the mmWave bands consider parameters such as characteristics defined in 3GPP TR 38.901, beam-forming, antenna configuration, scenarios, among others. Furthermore, the simulation results verify compliance within the ranges permitted by the 3GPP standards and verify reliability in indoor environmental scenarios by exploiting the Radio Environment Map (REM). Therefore, the channel model implemented in this study is applicable to the actual design and establishment of 5G networks, presenting a method to evaluate and validate RF performance by adjusting various parameters.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.406-413
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• 1997

근전도(EMG:Electromyogram)를 사용하여 국부 근육 피로(Localized Muscle Fatigue)를 정량화으로 분석 하기 위해 널리 이용되고 있는 AR(Autoregressive)모델의 1차 계수, RMS(Root Mean Square), ZCR(Zero Crossing Rate), MPF(Mean Power Frequency), MF(Median Frequency)를 선택하여, 근육이 발휘하는 힘과 시간의 흐름에 따라 근육 피로의 정도를 민감하게 나타내는 매개변수를 규명하였다. 피실험자 10명의 좌우 척추세움근(Erector Spinae Muscle)을 대상으로 등장수축(Sustained Isometric Contraction)조건에서 허리의 신전(Extension)운동을 실시하였다. 이때 발휘해야 하는 힘의 수준은 15%, 30%, 45%, 60%, 75% MVC 로 정하였고 각 수준마다 20초 동안 근전도를 측정하 였다. 데이터 분석은 총20초 구간의 근전도를 0.5초 간격으로 나누어 매개변수들을 각각 구하고 분석을 실시하였다. 시간의 흐름에 대한 피로도 분석 결과, AR 모델의 1차 계수와 MPF가 유의한 차이를 보였으며, 낮은 수준의 %MVC에서는 AR 계수가, 높은 수준에서는 MPF가 민감한 반응 결과를 나타냈다. 그리고 근육이 발휘하는 힘의 정도를 분석하기 위해 주로 사용되고 있는 RMS 보다는 더 AR 계수가 모든 수준에서 뚜렷하게 차이를 보인 것이 확인되었다. 따라서 AR 모델의 1차 계수가 근육의 피로 정도와 힘의 수준을 다른 매개변수에 비해 더욱 민감하게 구별함이 입증되었다. 이러한 결과는 다른 분야에서도 근육 피로를 정량적으로 측정하는데 사용될 수 있을 것으로 생각되며, 개인적 변이도를 고려한 확률 기법을 사용한다면 보다 정확한 근전도 분석이 이루어질 것으로 기대된다.있음을 알 수 있었다. 사료된다.의 결과는 자전거 에르고노미터의 결과가 트레드밀의 결과에 87.60%정도 나타났다.음을 관찰하였다. 특히 vitamin C와 E의 병용투여는 상승적으로 적용하여 간세포손상을 더욱 억제시킴을 알 수 있었다.mance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business portfolio properties, we obtained three findings. First, only VI (Vertical integration) has a significant positive correlation with ROS. Second, when using TFP growth as an dependent variable, both TR(Technological Relatedness) and f[ are signif

• Korea Trade Review
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• v.48 no.2
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• pp.71-94
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• 2023

The purpose of this study is to prove the effect of psychic distance between home country and host country on overseas foreign direct investment(OFDI) of Spanish companies through panel analysis. The panel data was based on cultural, institutional, economic, and geographical distance data over the past decade between Spain and Spain's OFDI countries. According to the Random Effect Model(REM) analysis, cultural distance(CULD) had a negative effect on OFDI, while institutional distance(INSD) had a positive effect. Among economic distances, income size distance(GDP) had a positive effect on OFDI, but export size distance(EXPO) had a negative effect. Geographic distance(PKM) had a negative impact. Meanwhile, according to the results of quantile regression analysis to prove the psychic distance effect by OFDI size, the effects of CULD and INSD in the quartile (75%) to which Korea belongs were the same as the REM analysis results. In addition, GDP and EXPO had a positive effect, and PKM had a negative effect but EXPO had a positive effect. Therefore, FDI host countries need to establish differentiated strategies through quantile analysis while making continuous efforts to improve the system.