• 대한전자공학회논문지SP
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• 제45권4호
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• pp.71-77
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• 2008

이 논문은 산업용 방사선영상을 비선형왜곡의 영향으로부터 복구하는 방법을 제시한다. 비선형 형태의 모델을 구현하기 위해 역자승법칙과 비어의 법칙에 근거한 해석적 방법을 고안한다. 방사선 선원과의 위치설정에 따른 다양성에 기인한 기하학적 영향이 디지털화된 영상에 반영된다. 각도, 위치, 흡수상수, 길이, 너비 및 화소수 산출 등과 같은 파라미터 값으로 표현하는 모델관련 특성을 샘플영상과 일치하도록 모델 내에 수식적으로 규정하였다. 모델과 최근접한 영상으로의 복구를 위한 탄젠트 기울기 기반 보정기법을 고안하였다. 이 방식을 강판튜브 방사선영상에 적용하여 영상을 복구한 결과가 제시되고 논의된다.

• 한국대기환경학회지
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• 제25권4호
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• pp.339-346
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• 2009

The objectives of this study were to introduce spatial interpolation methods which have been applied in recent papers, to apply three methods (nearest monitor, inverse distance weighting, kriging) to domestic data (Ulsan cohort) as an example of estimating the personal exposure levels. We predicted the personal exposure estimates of 2,102 participants in Ulsan cohort using spatial interpolation methods based on information of their residential address. We found that there was a similar tendency among the estimates of each method. The correlation coefficients between predictions from pairs of interpolation methods (except for the correlation coefficient between nearest montitor and kriging of CO and $SO_2$) were generally high (r=0.84 to 0.96). Even if there are some limitations such as location and density of monitoring station, spatial interpolation methods can reflect spatial aspects of air pollutant and spatial heterogeneity in individual level so that they provide more accurate estimates than monitor data alone. But they may still result in misclassification of exposure. To minimize misclassification for better estimates, we need to consider individual characteristics such as daily activity pattern.

• 대한기계학회논문집A
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• 제41권11호
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• pp.1099-1108
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• 2017

동일한 시험조건에서 반복시험으로부터 얻어진 실험 데이터는 이론적으로 동일한 값을 가져야 한다. 그러나 실제 데이터 결과는 다양한 환경 요소들에 의해 발생하는 오차와 불확실성을 가지게 되어 시험 값이 변동량을 가진다. 이는 정확한 실험 데이터를 얻는데 제한사항이 된다. 본 연구에서는 확률통계 방법을 이용하여 불확실성을 가진 입력변수의 유효범위를 결정하는 알고리즘을 제안하였다. 또한 실제 현장에서 사용되는 볼트 체결 마찰계수 데이터를 이용하여 제안된 알고리즘을 적용하여 불확실성을 내재한 입력변수의 유효범위를 산출하고 이에 대한 신뢰성 평가를 하였다.

• 한국소음진동공학회논문집
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• 제15권5호
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• pp.527-535
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• 2005

This paper explains a general coupling system in terms of the system parameters. impedance of a cavity or mobility of a structure. To easily access the mechanism of the structural-acoustic coupled system, a simple expression is derived. A general coupled equation is also derived of a general coupled problem constituted a flexible structure and an opening boundary in terms of vector and matrix notation, and is analyzed the coupling phenomena using the understanding acquired simple coupled system. The paper shows that the general coupled equation is expanded version of the simple coupled equation by some limiting checks. The paper also shows that the degree of coupling is proportioned to a stiffness of the acoustic system and a modal coupling coefficient, but is in inverse proportion to a mass of the structural system and the difference of the excitation frequency and resonant frequency of the acoustic or structural system.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권3호
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• pp.51-64
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• 2015

In the present study, we develop two history matching techniques based on Markov chain Monte Carlo method where radial basis function and Gaussian distribution generated by unconditional geostatistical simulation are employed as the random walk transition kernels. The Bayesian inverse methods for aquifer characterization as the developed models can be effectively applied to the condition even when the targeted information such as hydraulic conductivity is absent and there are transient hydraulic head records due to imposed stress at observation wells. The model which uses unconditional simulation as random walk transition kernel has advantage in that spatial statistics can be directly associated with the predictions. The model using radial basis function network shares the same advantages as the model with unconditional simulation, yet the radial basis function network based the model does not require external geostatistical techniques. Also, by employing radial basis function as transition kernel, multi-scale nested structures can be rigorously addressed. In the validations of the developed models, the overall predictabilities of both models are sound by showing high correlation coefficient between the reference and the predicted. In terms of the model performance, the model with radial basis function network has higher error reduction rate and computational efficiency than with unconditional geostatistical simulation.

• 융합신호처리학회논문지
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• 제13권4호
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• pp.233-237
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• 2012

본 논문에서는 RTDNN과 FLC를 이용해서 주신경망을 보상하는 제어시스템을 제안한다. 주신경망이 학습을 완료한 후 외란이나 부하변동이 생겨 오브 슛 내지는 언더 슛을 나타낼 때 적절히 조정하기 위해 퍼지 보상기를 사용하여 원하는 결과를 얻을 수 있도록 하였다. 그리고 제어대상의 역모델 신경망에서 학습시킨 결과를 이용하여 주신경망의 가중치를 변경시킴으로서 제어대상의 원하는 동적 특성을 얻게 된다. 모의 실험 결과 제안한 신경망 제어기의 양호한 응답 특성을 확인 할 수 있다.

• 한국농공학회논문집
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• 제51권2호
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• pp.7-14
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• 2009

The purpose of this study is to identify how much the MODIS NDVI (Normalized Difference Vegetation Index) can explain the forest soil moisture simulated from SWAT (Soil and Water Assessment Tool) model. For ChungjuDam watershed ($6,661.3\;km^2$) which covers 82.2% of forest, the SWAT model was calibrated for four years (2003-2006) at two locations of the watershed using daily streamflow data and was verified for three years (2000-2002) with average Nash and Sutcliffe model efficiencies of 0.69 and 0.75 respectively. For the period from March to June, the average spatial correlation between 16 days composite MODIS NDVI and the corresponding SWAT forest soil moisture was 0.90. The two variables averaged for each data set during that period showed an inverse relation with the average coefficient of determination of 0.55.

• 한국직업건강간호학회지
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• 제16권2호
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• pp.147-157
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• 2007

Purpose: The purpose of this study was to identify job stress, burnout experience and job satisfaction in nurses and to identify their relationships. Method: The data were collected from 280 nurses employed in one general hospital, using the structured questionnaire. The data analyzed using SPSS Win program for descriptive statistics, t-test, ANOVA, and Pearson correlation coefficient. Result: There were significant differences in job stress, burnout experience and job satisfaction by current working unit, working period, scheduled to work as a nurse, cause to satisfaction, periods in night shift, level of adaptation, and health status. There was a significant positive correlation between job stress and burnout experience, and a inverse correlation between job stress and job satisfaction. Conclusion: The study findings show that job stress, burnout experience, and job satisfaction of nurses are correlated each other. Therefore, it is need to maintain a proper level of nurses' job stress and burnout experience through various ways to improve the situation. As a result, job satisfaction will be promoted and human resources will be managed appropriately.

• 한국간호교육학회지
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• 제17권2호
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• pp.190-199
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• 2011

Purpose: This study was done to investigate suicidal ideation and spirituality of college students. Method: The participants were 295 college students located in Busan city and Kyung Nam Province. The study used a 'Suicidal Ideation Questionnaire' and a 'Korean Spirituality Scale'. The collected data was analyzed for t-test, ANOVA, Pearson's correlation coefficient, and stepwise multiple regression with the SPSS/WIN 19.0 program. Result: The level of suicidal ideation and spirituality of the participants averaged 1.73 and 3.44 respectively. In each sub-factor, meaning and purpose of life was the highest at 3.70 points. In differences of suicidal ideation and spirituality followed by general characteristics, there were significant differences according to gender, major, religion, and cohabitation. There were inverse correlations among suicidal ideation, spirituality level, connectedness, meaning and purpose of life, inner resources, and awareness. Suicidal ideation was significantly associated with major, spirituality level, connectedness, and meaning and purpose of life which explained 22% of variance in suicidal ideation. Conclusion: Future research should examine relations between college students' suicidal ideation and spirituality level through random sampling. Development of a program to lessen college students' suicidal ideation and to raise their spirituality level should be prudent.

• 지역사회간호학회지
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• 제17권3호
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• pp.364-375
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• 2006

Purpose: The purpose of the study was to investigate burden and the qualify of life in caregivers who are taking care of home-based rare and incurable disease patients. Methods: The subjects of this study were 300 caregivers of rare and incurable disease patients registered at five health centers in Seoul. A survey was conducted by mail and visit in person during the period from the 25th of March to the 12th of May 2005. Collected data were analyzed through t-test, ANOVA, Pearson's correlation coefficient. Result: The mean burden of caregivers was 3.42, and the mean qualify of life of caregivers was 2.71. Burden and QoL showed significant differences according to caregivers' characteristics such as sender, age, relation to the patient, academic qualification, religion, occupation, monthly household income and perceived health condition. Caregivers' burden was in an inverse correlation with their quality of life. Conclusions: According to the results of this study, rare and incurable disease caregivers' burden and their quality of life were in a significant correlation with each other. In order to improve caregivers' quality of life by reducing their burden, we need to reestablish comprehensive policies for rare and incurable disease management including nursing intervention strategies for caregivers.