• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.513-516
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• 2008

본 연구는 부식생성물의 공극충전에 의한, 부식 반응량 및 이산화탄소의 확산속도 변화를 고려한 철분혼입 콘크리트의 염화물이온침투 예측모델에 관한 연구이다. 본 모델은 염화물이온 침투영역에서 염화물이온과 철이온의 반응 및 염화물이온의 확산에 기초한다. 또한 본 모델은 콘크리트 조직이 부식 생성물로 인해 치밀해져, 콘크리트의 염화물이온 침투저항성이 억제되는 것에 대해서도 해석이 가능하다. 모델에 의한 예측치와 철분을 혼입한 콘크리트에 있어서의 실측값은 잘 일치하였고, 재령이 경과함에 따라 철분무혼입 콘크리트에 비해 염화물이온 침투속도가 상당히 늦어지는 것으로 나타났다. 결론적으로 본 모델은 대기중에 노출된 콘크리트의 물시멘트비 및 철분 혼입 유무와 혼입율에 따른 염화물이온 침투 예측이 가능하였다.

• 콘크리트학회논문집
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• 제14권6호
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• pp.813-822
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• 2002

본 연구에서 초기재령 콘크리트의 단면 내 수화도와 온도 및 습도분포를 구하는 3차원 유한요소 해석 프로그램을 개발하기 위한 수화도에 따른 재료 모델을 제시하고, 수치해석 절차에 관하여 정립하였다. 재료물성이 급격히 변화하는 초기재령 콘크리트의 거동을 모사하는 과정에서 온도 및 습도에 관련된 재료 물성이 수화도에 따라 결정하였다. 또한 수분거동 연구는 경화한(mature) 콘크리트에 대해서는 여러 연구자에 의해 수행되었지만, 초기재령 콘크리트의 전달계수, 수분용량에 관한 연구는 제대로 정립되지 않은 실정이다. 또한 일반적으로 보통콘크리트에서 무시되는 수분감소항은 고강도 및 고성능 콘크리트의 자기건조(self-desiccation)와 관련된 자기수축(autogenous shrinkage)을 유발하고, 이는 구조물의 장기 내구성 및 사용성 측면에서 중요한 관심사이다. 따라서 본 연구는 초기재령 콘크리트의 온도 및 수축에 의한 응력을 평가하기 위하여, 고강도 및 고성능 콘크리트를 포함한 초기재령 콘크리트의 온도 및 수분거동을 적절히 표현하는 수학적 재료 모델을 제시하고, 콘크리트의 단면 내 수화도와 온도 및 습도분포를 결정하는 3차원 유한요소 해석 프로그램을 개발하였다. 개발된 해석프로그램을 이용한 수치해석 결과는 실험결과와의 비교를 통하여 그 타당성을 검증하였다.

• 한국광물학회지
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• 제27권2호
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• pp.85-95
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• 2014

백악기 말기 불국사 관입암류에 해당하는 대구 대덕산 규장질 관입암체 내에서는 구형, 방사형의 두 가지 형태의 전기석 결정이 발견된다. 이 연구에서는 두 가지 형태를 보이는 전기석의 광물화학적인 특징과 더불어 결정화 환경이 형태적인 차이점에 끼친 영향에 대해 알아보았다. 두 전기석은 화학적으로 모두 철전기석에 해당하며, 구형 전기석은 방사형 전기석에 비해 Al이 풍부하고 Ca, Na, K, Fe, Mn, Mg 등이 결핍되어 X 및 Y 사이트가 채워져 있지 않음을 알 수 있었다. 한편 확산규제결합(DLA) 모델에 의하면 결정의 성장형태가 불규칙적일수록 마그마의 유동이 활발하다고 알려져 있다. 따라서 방사형 전기석이 비교적 유동적인 환경에서 결정화되었음을 알 수 있으며, 마그마의 분화에 따라 고철질 성분에 비해 규장질 성분이 농집되면서 마그마 환경이 안정되고 구형의 전기석을 만들어 내기에 적합한 환경이 조성되었을 것이라 판단된다.

• Korean Journal of Radiology
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• 제22권7호
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• pp.1021-1033
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• 2021

Objective: To assess the expression of vascular normalization genes in different molecular subtypes of breast cancer and to determine whether molecular subtypes with a higher vascular normalization gene expression can be identified using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI). Materials and Methods: This prospective study evaluated 306 female (mean age ± standard deviation, 50 ± 10 years), recruited between January 2014 and August 2017, who had de novo breast cancer larger than 1 cm in diameter (308 tumors). DCE MRI followed by IVIM DWI studies using 11 different b-values (0 to 1200 s/mm²) were performed on a 1.5T MRI system. The Tofts model and segmented biexponential IVIM analysis were used. For each tumor, the molecular subtype (according to six [I-VI] subtypes and PAM50 subtypes), expression profile of genes for vascular normalization, pericytes, and normal vascular signatures were determined using freshly frozen tissue. Statistical associations between imaging parameters and molecular subtypes were examined using logistic regression or linear regression with a significance level of p = 0.05. Results: Breast cancer subtypes III and VI and PAM50 subtypes luminal A and normal-like exhibited a higher expression of genes for vascular normalization, pericyte markers, and normal vessel function signature (p < 0.001 for all) compared to other subtypes. Subtypes III and VI and PAM50 subtypes luminal A and normal-like, versus the remaining subtypes, showed significant associations with K^trans, k_ep, v_p, and IAUGC_BN90 on DEC MRI, with relatively smaller values in the former. The subtype grouping was significantly associated with D, with relatively less restricted diffusion in subtypes III and VI and PAM50 subtypes luminal A and normal-like. Conclusion: DCE MRI and IVIM parameters may identify molecular subtypes of breast cancers with a different vascular normalization gene expression.

• 천문학회지
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• 제44권2호
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• pp.49-58
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• 2011

We calculate the energy spectra of cosmic ray (CR) protons and electrons at a plane shock with quasi-parallel magnetic fields, using time-dependent, diffusive shock acceleration (DSA) simulations, including energy losses via synchrotron emission and Inverse Compton (IC) scattering. A thermal leakage injection model and a Bohm type diffusion coefficient are adopted. The electron spectrum at the shock becomes steady after the DSA energy gains balance the synchrotron/IC losses, and it cuts off at the equilibrium momentum $p_{eq}$. In the postshock region the cutoff momentum of the electron spectrum decreases with the distance from the shock due to the energy losses and the thickness of the spatial distribution of electrons scales as $p^{-1}$. Thus the slope of the downstream integrated spectrum steepens by one power of p for $p_{br}$ < p < $p_{eq}$, where the break momentum decreases with the shock age as $p_{br}\;{\infty}\;t^{-1}$. In a CR modified shock, both the proton and electron spectrum exhibit a concave curvature and deviate from the canonical test-particle power-law, and the upstream integrated electron spectrum could dominate over the downstream integrated spectrum near the cutoff momentum. Thus the spectral shape near the cutoff of X-ray synchrotron emission could reveal a signature of nonlinear DSA.

• 한국보건간호학회지
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• 제8권1호
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• pp.30-52
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• 1994

This study was conducted to diffusion of the health promotion program about no smoking in industry. No smoking program model composed of assessment, plan, implementation and evaluation was developed through the method of literature review and applied to 27 smokers of the management team and dept. of the 1st production in one industry, from October 27 to November 3D, 1993. For the analysis, descriptive statistics and paired t-test were used. The result of this study are summarized as follows: 1. The object was composed of no smoking and reduced smoking. The achievement rate of object was $48\%$. 2. As a result of the implementation of no smoking program, $11\%$ of no smoking rate was obtained. 3. After application of no smoking program, the health age was a little lower but statistical significations was not found. 4. Health education and support of family were effective in health promotion program. Complementary measures about indivisual activity for no smoking were required in no smoking program. In conclusion, subject's response about no smoking program was high and health education and support of family were effective in health promotion· program. And nurses were expected to do their roles as a planner, intervener, manager and supporter in health promotion services.

• 품질경영학회지
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• 제38권2호
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• pp.161-170
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• 2010

Diffusion of e-learning has been accelerated according as the convenience and effectiveness have been increased rapidly due to the advancement of information technology. However, there has been few studies on systematic evaluation of its performance. SERVQUAL model was applied to evaluate the service quality of a 100% on-line lecture opened in a major Korean university. Two classes, one for 71 undergraduate students, the other for 79 graduate students, were opened for the lecture. The gaps between the expected service and the perceived service scores were compared with respect to sex, age, and e-learning experience. Although the gap score of male and female students were not different significantly, the gap scores among the other comparative groups were different. The perceived score of the older group with more than thirty ages was lower than that of the younger group. It seems that the older group evaluated the score based on the practical use of the subject since they are part-time students with jobs. Also, the perceived score of the group with previous e-learning experience was higher than that of the group with no e-learning experience. It seems that the experienced group evaluated it compared with the previous e-learning satisfaction. As it might be expected, the groups with higher perceived scores had stronger intention to recommend the e-learning lecture to other students.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.608-615
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• 2013

The major countries including Korea extend the national investment on R&D and implement the business performance diffusion policy as the knowledge based competition age arrives recently. The necessity for risk management and systematic management system for R&D achievement have been appeared to prevent the failure as the R&D scale becomes larger as it was said. For this matter, the organization such as NASA and DoD in USA defines the Technology Readiness Level (TRL) as a quantitative accomplishment management index and utilize the Technology Readiness Assessment (TRA) system as a criterion. Such tool is evaluated as very effective in the R&D project purposed the practicalization. It is expected that the disadvantage of evaluation system which is oriented to the academic accomplishment in its contents of current research and to contribute greatly to the practicalization of outcomes when such technology readiness level concept is applied to Korean national construction and transportation R&D project. Accordingly, this study analyzed the concept of TRL·TRA, the characteristics and current evaluation management system of Korean national construction and transportation R&D project and suggested the construction and transportation R&D project TRL·TRA performance model to accomplish the practicalization purpose.

• 대한지리학회지
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• 제30권3호
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• pp.311-323
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• 1995

본 연구에서는 종로구 국민학교의 입지와 대안적 학구안을 제시하고자 하였다. 연 구 방법은 GIS Network의 입지-배분 모델을 이용하였다. 본 연구는 학교 입지에 각 변인의 가중치를 고려하지 못하고 분석 단위를 동단위로 했다는 점과 학구 조정에 있어서 학생들의 분포를 도로상에 균등하게 분포시킴으로써 현실과의 차이점이 다소 생길 수 있는 문제점을 가지고 있음을 밝혀 둔다. 기존의 학군에서 평균 통학거리 8,568m, 최대 통학거리 16,804m 인데 반하여 수정된 최소 통학거리 학군에서는 평균 통학거리가 8,328m, 최대 통학거리가 16,182m로 나타났다. 그리고 통학안정성 중심의 조정 학군에서는 평균 통학거리가 8,517m, 최대 통학거리가 16,768m이었다.

• 보건교육건강증진학회지
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• 제21권4호
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• pp.35-49
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• 2004

The purpose of this study was to analyze variables associated with smoking and selected health behaviors. This study targeted adult men and women over 20 of age. The sample population was drawn from the national sample, and the samples were chosen from the telephone book. A total of 1,500 cases were collected through a telephone based interview survey. As a tool for this study, a structured questionnaire was developed. the variables included self-perceived health status, and selected 7 health behaviors; smoking behavior, physical activities, eating habit, weight control, alcohol consumption, stress management, and cancer exam. The healthy life practice actions of Trans-theoretical model have been classified into five stages. Smokers were more likely than non-smokers to positive attitudes toward smoking and the impact of smoking in this study. This means that smokers's awareness toward the impact of smoking is very week. Smoking behavior was significantly related to other health related behaviors based on the correlation analysis. However, gender, engaging in regular physical activities, moderate consumption of alcoholic beverages, and receiving a cancer examination were the variables that can explain and predict a person's stages of adopting a non-smoking behavior. Self perceived health status was closely related to other health behaviors. Gender, age, and monthly household income were important demographic variables that have significant relationship with the self-perceived health status. Among the health behaviors, regular physical activities and weight control were significant predictable variables. Similar results have been found in the National health and Nutrition examination survey in Korea. As a result of this study, it was found that among the selected health behaviors, engaging in physical activity was an important variable to increase positive sense of health and non-smoking behaviors. Educational and policy level input is needed to increase awareness and provide chances to participate in fitness activities. To those who maintain exercise, the environmental support and diffusion of knowledge information and education data should be strengthened. To change attitudes toward smoking, more in-dept awareness campaign and education should be provided according to people's different behavioral status. In addition, not only diffusing health education data and delivering knowledge information through related programs, but also environmental support system that helps an individual maintain his/her action is required. Such a support system means settlement of the health enhancement base of school, workplace and community should be carried out, and the policy level support and regular programs should be provided and spread to the unit of community.