• Journal of the Korean Institute of Educational Facilities
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• v.24 no.2
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• pp.18-24
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• 2017

본 연구는 청소년 스트레스 호르몬 변화를 보기위한 연구로 컬러 컨설팅 환경개선에 따른 스트레스 호르몬 변화를 연구하였다. 청소년 스트레스 연구들에 따르면, 아동이나 청소년도 성인만큼 스트레스를 경험하고 있고 청소년들의 스트레스는 정서적 부적응과 신체적 건강에도 영향을 미친다. 스트레스가 지속되면 부신피질에서 스테로이드 호르몬인 코티솔도 분비하는 근거를 통해 환경변화로 생긴 코티솔 분비를 측정하였다. 코티솔 분비를 통한 스트레스 반응 정도 측정은 침해성을 최소화하기 위한 간편한 방법인 타액검사로 실시하였으며 비 침습적인 방법으로 특별한 장비나 도움이 없이 수집할 수 있었고 부작용이 적은 효율적 검사였다. 연구 결과 전체 학생(46명)의 코티솔은 환경개선 사전($0.121{\pm}0.087{\mu}g/dL$)에 비해 사후($0.096{\pm}0.058{\mu}g/dL$)에 감소하였고(t=1.718, p=.093) 중고등학생(36명)의 코디솔은 사전($0.137{\pm}0.092{\mu}g/dL$)에 비해 사후($0.104{\pm}0.062{\mu}g/dL$)에 감소하였으며, 유의수준 10%에서 통계적으로도 유의미한 차이를 보였다(t=1.750, p=.089). 따라서 환경 개선 전에 비해 환경 개선 후 청소년들의 스트레스가 감소되었음을 알 수 있다. 하지만 초등학생(10명)의 코티솔은 사전($0.064{\pm}0.023{\mu}g/dL$)에 비해 사후($0.065{\pm}0.016{\mu}g/dL$)에 변화를 보이지 않아, 유의수준 5%에서 통계적으로 유의미한 변화는 나타나지 않았다(t=-0.121, p=0.906). 따라서 후두엽이 발달하는 중학생 시기는 환경 변화에 민감하며 색채 자극에 크게 영향을 미치는 시기인 만큼 본 연구에서 환경전후로 검사한 코티솔 분비의 측정값도 감소함을 볼 수 있었다. 하지만 본 연구는 환경 변화에 코티솔 분비량에 유의미한 변화를 나타내지 않은 초등학생들은 스트레스 호르몬 변화에는 차이가 없었지만 환경변화의 자극이 없었다고 볼 수는 없다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.373-381
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• 2017

This study was conducted to establish and verify a theoretical model that explains the factors and pathways influencing the psychological well-being of nurses. The subjects of this study were nurses working in four general hospitals with over 200 beds in B city and G province. The results of verifying the path coefficient of the nurses' job rotation stress showed that job rotation stress had a significant effect on challenge stress, hindrance stress, and nurses' psychological well-being, while hindrance stress had a negative effect on nurses' psychological well-being. Nurses' job rotation stress had direct effects on challenge stress, hindrance stress, and psychological well-being. Hindrance stress had a direct effect on psychological well-being. In addition, nurses' job rotation stress had an indirect effect on psychological well-being through hindrance stress. Nurses who experienced job rotation showed challenge and hindrance stress. Since hindrance stress interferes with the psychological well-being of nurses, it is necessary to manage stress and make efforts in the nursing organization. Therefore, nursing organizations should establish a positive organizational environment and develop systematic strategies so that job rotation can be a challenging stress factor for nurses.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.295-295
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• 2022

강우 변동성과 기온의 증가 추세로 전 세계 여러 지역에서 가뭄의 빈도, 지속기간, 심각도, 영향면적이 증가하고 있다. 기후변화로 인한 극심한 가뭄은 담수 생태계에 심각한 결과를 가져올 수 있으며, 이는 중대한 사회적 경제적 영향을 미칠 수 있다. 본 연구에서는 낙동강 수질오염총량관리 단위유역에서 기상학적 가뭄 발생 시 하천 수생태계가 받는 수질 스트레스 위험도가 식별된다. 기상학적 가뭄은 표준강수지수(SPI)로 한정되며 하천 수질은 BOD로 한정되어 분석이 수행된다. 또한, 본 연구에서는 하천의 수질 스트레스를 식별하기 위하여 가뭄 시 환경영향 지수인 Environmental Drought Condition Index-water quality(EDCI-wq)를 제안한다. EDCI-wq는 기상학적 가뭄이 발생하였을 때 수생태계가 평상시 대비 스트레스를 받을 가능성을 표현한 지수이다. 최종적으로 산정된 EDCI-wq를 기반으로 하천 구간별로 관심, 주의, 경계, 심각 단계 구분 기준을 마련하여 기상학적 가뭄 발생 시 하천 수생태계가 받는 수질 스트레스를 단계적으로 식별할 수 있는 수질 스트레스 위험도 지도가 작성된다.

• Korean Journal of Environmental Biology
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• v.41 no.1
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• pp.41-53
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• 2023

E171, a mixture of titanium dioxide, has been widely used as a food additive due to its whitening effect and low toxicity. However, it has been proven that E171 is no longer safe for public health. So far, there are insufficient studies on the toxic effects of E171 on organisms especially using standardized test methods. In this study, toxicity assessments of E171 to two aquatic species, water flea (Daphnia magna) and zebrafish (Danio rerio), were performed using modified standardized test methods based on the physicochemical properties of E171. The hydrodynamic diameter, polydispersity index, and turbiscan stability index (TSI) were measured to ensure the dispersion stability of E171 in exposure media during the test period. The EC₅₀ for immobilization of water flea was 141.7 mg L^-1 while zebrafish was not affected until 100 mg L^-1 of E171. Measurements of reactive oxygen species (ROS) and antioxidant enzyme activities confirmed that E171 induced oxidative stress, leading to the activation of superoxide dismutase and catalase in both water flea and zebrafish, although the expression of antioxidant enzyme genes differed between species. These results suggested the potential risk of E171 to aquatic organisms and provided toxicological insights into the impacts of E171 on the environment.

• Journal of Environmental Impact Assessment
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• v.28 no.1
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• pp.49-62
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• 2019

Environmental changes can affect life-history traits, such as growth rate and reproduction, and organisms adapt on a given environmental condition to maximize ecological fitness. This study shows the effects of water temperature and dissolved oxygen level on early growth and accumulated damage in fish using a dynamic-state-dependent model. I have hypothesized that the level of foraging activity is related to growth and stress and so the optimal level can maximize reproductive success - ultimately, fitness. The critical temperature and dissolved oxygen (DO) is also defined as inducing the maximum growth rate at the level. So, the model predicts the highest growth rate at oxygen saturation and lower growth rate at lower or higher level of DO in water. Lower DO (i.e., hypoxia) causes slower growth rate through higher amount of accumulated stress whereas higher DO (i.e., hyperoxia) induces faster growth rate, but smaller body size. In addition, I show that there is lower impact when considering simple or independent environmental factors on environmental assessment. My findings suggest that multiple environmental factors as physiological ecology approach should be considered to improve impact assessment in environmental changes and a further study is needed to develop advanced assessment tools considering multiple environmental factors.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.6
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• pp.509-523
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• 2023

The high-level nuclear waste (HLW) repository is exposed to complex environmental conditions consisting of high temperature, high humidity, and radiation, resulting in structural deterioration. Therefore, structural health monitoring is essential, and piezo sensors are used to detect cracks and estimate strength. However, since the monitoring sensors installed in the disposal tunnel and disposal container cannot be replaced or removed, the quantitative life of the monitoring sensor and its suitability must be assessed. In this study, the life of a piezo sensor for monitoring was assessed using an accelerated life test (ALT). The failure mode and mechanism of the piezo sensor under high temperature conditions were determined, and temperature stress's influence on the piezo sensor's life was analyzed. ALT was conducted on temperature stress and the relationship between temperature stress and piezo sensor life was suggested. The life of the piezo sensor was assessed using the Weibull probability distribution and the Arrhenius acceleration model. The suggested relationship can be used in multiple stress ALT designs for more precise life assessment.

• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.27-36
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• 2007

A model test was performed to evaluate the stability of a new earth retention system with a prestressed wale. For the model test, the dimensional analysis of a full-scaled earth retention system with prestressed wales was performed. Details of the dimensional analysis of the new earth retention system were presented in this paper. Based on the results of the dimensional analysis, the model-scaled earth retention system with a prestressed wale was simulated. The lateral earth pressures on the wall, the lateral deflection of the prestressed wale, the sectional force on members of the prestressed wale system, and the loads of struts were measured during construction simulation. The measured results were evaluated and compared with those of the design criterion. From the measurements, the behavior of this earth retention system was investigated.

• Journal of The Korean Association For Science Education
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• v.34 no.2
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• pp.165-173
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• 2014

The purpose of this study is to investigate the stress factors experienced by science teachers and stress related to science teaching. To do these, I have developed the Science Teacher Stress Inventory, which consisted of 50 stress factors with subcategories such as student characteristics, teacher characteristics, school environment, administrative procedures, and conditions of service. 104 science teachers have participated in this questionnaire survey. Additionally, I got 109 stress cases related to science teaching from surveys of 25 science teachers. Results are as follows: first, stress from students characteristic and administrative procedures are perceived as having more stress factors than teacher characteristics, school environment, and conditions of service. Second, stress in affective domains such as students' low motivation in science and insincere class attitude is perceived as having more stress factors than stress in cognitive domain. Third, female science teachers are significantly more stressed than male science teachers. Fourth, students' low motivation and low understanding in science learning are the most stressful factors in stress related to science teaching. Fifth, science teachers feel more stress in evaluation such as experiment test and joint-set exam questions.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.7 no.2
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• pp.233-246
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• 1996

There have been great deal of studies on adult stress but comprehensive studies on adolescent stress are not sufficient. Because adolescents have different developmental tasks from adult's, and because they spend most of their time in a structured environment such as school, the research on adolescent stress is necessary. So, this study empirically investigated the types of stress and coping which students experience and their coping mechanisms in a stressful situation. In this study, perceived social support was considered as stuructural variable, and cognitive appraisal as a process variable, while existing researches tried to explain the coping mechanism only from the viewpoint of structure, or hypothesized the structure variable in the process term. The relation ships between cognitive appraisal and perceived social support on coping behavior were evaluated. Survey on 519 high school students in Seoul showed that cogitive appraisal was a structural variable which varied across the types of stress, and that perceived social support was a structure variable which was independent of the type of stress. Cognitive appraisal was related more to the qualitative process of stress appraisal than coping behavior, and perceived social support was an important structure which influenced both the appraisal process and coping behavior.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.10a
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• pp.218-220
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• 2010

우리나라 연안 해역은 빈번한 선박조우로 인하여 해양사고 발생 잠재 위험이 높은 해역으로 분류되고 있으나 해상교통의 정량적인 평가의 미흡으로 맞춤형 안전대책이 제대로 수립되고 있지 않는 것이 현실이다. 본 연구에서는 해상교통 안전성 평가모델 중 하나인 IWRAP(IALA Waterway Risk Assessment Program)에 대한 기본적인 소개와 함께, 울산항을 대상으로 한 평가 사례 소개, 기존 유사한 연구와의 비교를 하고자 한다.