• Earthquakes and Structures
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• 제19권3호
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• pp.197-214
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• 2020

Diagrid structures have been introduced as a fairly modern lateral load-resisting system in the design of high-rise buildings. In this paper, a novel diagrid system called tube-in-tube diagrid building is introduced and assessed through pushover and incremental dynamic analyses. The main objectives of this paper are to find the optimum angle of interior and exterior diagrid tube and evaluate the efficiency of diagrid core on the probability of collapse comparing to the conventional diagrid system. Finally, the seismic performance factors of the proposed system are validated according to the FEMA P695 methodology. To achieve these, 36-story diagrid buildings with various external and internal diagonal angles are designed and then 3-D nonlinear models of these structures developed in PERFORM-3D. The results show that weight of steel material highly depends on diagonal angle of exterior tube. Adding diagrid core generally increases the over-strength factor and collapse margin ratio of tall diagrid buildings confirming high seismic safety margin for tube-in-tube diagrid buildings under severe excitations. Collapse probabilities of both structural systems under MCE records are less than 10%. Finally, response modification factor of 3.0 and over-strength factor of 2.0 and 2.5 are proposed for design of typical diagrid and tube-in-tube diagrid buildings, respectively.

• Journal of Biosystems Engineering
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• 제17권4호
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• pp.344-353
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• 1992

This study was carried out to develop a fully-controlled plant growth system for studying the effects of environmental factors on plant growth. The plant growth system consists of the growth chamber, the measurement system for sensing and signal conditioning the environmental factors and the control system which includes control algorithm required for optimum operation and on-line monitoring. The results of the study on the performance of the controlled plant growth system are summarized as follows : 1. Under the light intensity of 18,000~20,000 lux, the temperature was controlled in the range of $22{\pm}0.4^{\circ}C$, the relative humidity of $70{\pm}5%$ respectively. 2. The $CO_2$ concentration was controlled in the range of $1,000{\pm}40ppm$(from 1st to 4th day) and $1,500{\pm}40ppm$(from 4th to 9th day). 3. The electric conductivity(EC) and pH of the nutrient solution were controlled in the range of $1.9{\pm}0.2mS/cm$ and $6.8{\pm}0.5pH$ respectively. 4. Under the above environmental conditions, the average fresh weight of leaf lettuce increased from 10g to 74g in 9 days with 24 hour lighting.

• Asian Journal for Public Opinion Research
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• 제11권2호
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• pp.145-162
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• 2023

This research investigates how users of Bilibili, a video sharing website based in China have responded to carbon neutrality. By conducting quantitative textual analyses on 3,311 comments on Bilibili using LDA topic extraction and content statistics, this research discovers that: (1) Bilibili users have assigned more weight to geopolitical topics (56.3%) than energy (22.0%) and environmental topics (21.7%). (2) When assessing carbon neutrality, Bilibili users considered geopolitical (53.8%) and energy factors (15.8%) more heavily than factors related to the class (9.2%), economy (8.9%), environment (8.7%), and definition (3.6%). (3) More Bilibili users had negative (64.6%) attitudes towards carbon neutrality, with only a small portion of them expressing positive (26.8%) and neutral (8.6%) attitudes. (4) Negative attitudes towards carbon neutrality were mainly driven by geopolitical concerns about the West's approach to China, other countries' free-riding on China's efforts and the West's manipulation of rules, doubts about the feasibility of energy transition and suspicion of capitalists exploiting consumers through this concept. This research highlights the geopolitical concerns behind the environmental attitudes of Chinese people, deepening our understanding to psychological constructs and crisis sensitivity of Chinese people towards environmental issues.

• 생물환경조절학회지
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• 제14권3호
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• pp.160-165
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• 2005

표고버섯의 생육과 품질은 환경요인에 직접적인 영향을 받기 때문에, 시설재배에서는 생육과 품질을 향상시키기 위해서 적절한 환경조절이 필요하다. 본 연구에서는 시설재배 하에서 야간 기온(무처리, $5{\~}11^{\circ}C,\;12{\~}18^{\circ}C$), 주간 상대습도(무처리, 6시간 및 12시간 가습), 풍속(무처리, 풍속 6시간 및 12시간 유지)에 대하여 버섯의 생체중, 건물중, 함수율, 갓의 직경, 두께, 착색도, 균병의 직경, 길이를 측정하였다. 야간 온도가 낮을수록 품질이 향상되었고, 생체중을 고려할 경우에 최저온도는 최저 생육온도 $3^{\circ}C$이상 $8^{\circ}C$ 이하가 적절하였다. 주간에 상대습도 ($70{\~}80\%$)를 계속 유지시키면 생체중은 증가하지만, 고품질을 얻기 위해서는 $50{\%}$정도가 적절하였다. 6시간 이상의 평균 풍속($1{\~}2\;m{\cdot}s^{-1}$) 처리구에서 생육과 품질이 양호하였고, 12시간 지속될 경우, 증발에 의하여 생체중은 감소하였으나, L값이 높은 것으로 나타났다. 표고버섯의 수량과 품질을 동시에 향상시키는 것은 쉽지 않지만, 수량과 품질에 관여하는 환경요인과의 관계를 분석함으로서 최적의 방법을 모색할 수 있을 것으로 판단된다.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.53.1-53.15
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• 2023

Background: Plastics are high-molecular-weight materials composed of long carbon chains. They are prevalent in daily life, present in various items such as food containers and microwavable packaging. Phthalates, an additive used to enhance their flexibility, are endocrine-disrupting chemicals. We utilized the data from the Korean National Environmental Health Survey (KoNEHS) cycle 3, representing the general South Korean population, to investigate the relationship between the use of plastics in refrigerator food storage and phthalate exposure. Methods: We assessed 3,333 adult participants (aged ≥ 19 years) including 1,526 men and 1,807 women, using data from KoNEHS cycle 3. Using the 75th percentile concentration, urine phthalate metabolites were categorized into high and low-concentration groups. χ² test was conducted to analyze variations in the distribution of each variable, considering sociodemographic factors, health-related factors, food intake, the use of plastics, and the concentration of urine phthalate metabolites as the variables. To calculate odds ratios (ORs) for the high-concentration group of urine phthalate metabolites based on the use of plastics in refrigerator food storage, logistic regression analysis was conducted. Results: In men, the use of plastics in refrigerator food storage had significantly higher adjusted ORs compared to those using the others. The adjusted ORs were calculated as follows: mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) had an OR of 1.35 (95% confidence interval [CI]: 1.05-1.72), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) had an OR of 1.48 (95% CI: 1.16-1.88), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) had an OR of 1.32 (95% CI: 1.04-1.66), ∑di(2-ethylhexyl) phthalate (∑DEHP) had an OR of 1.37 (95% CI: 1.08-1.74) and mono-n-butyl phthalate (MnBP) had an OR of 1.44 (95% CI: 1.13-1.84). Conclusion: The concentrations of urine phthalate metabolites (MEHHP, MEOHP, MECPP, ∑DEHP, and MnBP) were significantly higher in men who used plastics in refrigerator food storage compared to those using the others.

• Journal of Preventive Medicine and Public Health
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• 제29권1호
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• pp.91-102
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• 1996

Low back pain patients and controls of shipyard workers were surveyed between June 1995 and September 1995 to identify risk factors of industrial low back pain. The patients were 17 male workers who had got medical treatment for over 3 days because of industrial back pain. Controls were 51 male workers who had not have musculoskeletal disorder for one year before the survey. By univariate analysis, the workers who did overtime work 4 times or more for the last 2 weeks showed odds ratio of 3.67 on low back pain with the workers who did less overtime work. Carrying heavy materials was also associated with the low back pain and the odds ratio increased with the increase of carrying weight. Work space and work posture were not associated with the low back pain significantly. The welder had higher odds ratio than the other workers on low back pain. The duration of employment and job satisfaction did not affect the risk of low back pain. Multiple logistic regression analysis showed that frequency of overtime work for the last 2 weeks and carrying heavy materials among the risk factors were associated significantly with the low back pain. We found that important risk factors of low back pain of shipyard workers are work intensity factors such as overtime work and carrying heavy weight.

• 대한토목학회논문집
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• 제29권6D호
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• pp.761-770
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• 2009

철도는 다른 육상교통수단보다 에너지 효율성이 높은 환경 친화적인 교통수단이다. 예비타당성조사와 철도노선 선정 과정에서 에너지 효율성과 환경에 관한 문제들이 일반적으로 고려되고 있다. 철도노선 선정에서는 지형적인 특성 그리고 시설물의 관리와 운영을 중심으로 선정되고 있다. 철도노선선정에 영향을 미치는 환경관련 문제에 대해서 본 연구는 집중적으로 검토 분석하였다. 본 연구는 철도 및 환경전문가 그리고 철도 노선선정에 관련된 전문가 의견을 검토 분석하여 환경에 영향을 미치는 주요 항목의 가중치를 선정하였다. 환경 친화적인 철도노선을 선정하기 위하여 여러 대안이 비교되어야 하고 각 대안의 평가는 환경성을 검토하여야 한다. 이 문제를 해결하기 위해 본 연구에서는 계층구조를 이용하여 복잡한 문제를 간단하고 객관적으로 결론 내리는데 용이한 AHP 기법을 이용하였다. 이에 따라 전문가에 의한 환경평가항목의 가중치를 기본값으로 정하고 GUI를 활용한 정량화 시스템을 개발하였다.

• The Korean Journal of Ecology
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• 제18권2호
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• pp.255-263
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• 1995

Two poplar clones, I-214 (Populus euramericana) and Peace (P. Koreana × P. trichocarpa), were grown for 21 days in growth chambers at different CO₂concentrations (350, 700 and 2,000 μL·L-1). I-214 has stomata responding to environmental conditions in normal ways and Peace has unresponsive stomata to environmental factors including light, ABA, water stress and CO₂. In both plants, elevated CO₂ stmulated the growth of plant parts, especially leaf dry weight. And a CO₂ enrichment of 700 μL·L-1 CO₂ caused increment of net assimilation rate (NAR). The growth responses of these plants to CO₂ enrichment were different especially at high CO₂ condition (2,000 μL·L-1 CO₂). The total dry weight in Peace increased up to 2,000 μL·L-1 CO₂ but not in I-214. A CO₂ enrichment of 2,000 2,000 μL·L-1 CO₂ had little effect on NAR of I-214 but enhanced NAR of Peace. Although it is uncertain whether the different responses to CO₂ enrichment between I-214 and Peace resulted from the different properties of stomatal responses to long-term CO₂ treatment, the decrease in NAR is probably due in part to CO₂-induced stomatal closure in I-214 but not in Peace.

• 한국지형공간정보학회:학술대회논문집
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• 한국지형공간정보학회 2005년도 아시아 태평양 국제 GSIS 학술발표회
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• pp.61-72
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• 2005

The landslide risk assessment process consists of hazard risk assessment and vulnerability analysis. landslide hazard risk is location dependent. Therefore, maps and spatial technologies such as GIS are very important components of the risk assessment process. This paper discusses the advantages of using GIS technology in the risk assessment process and illustrates the benefits through case studies of live projects undertaken. The goal of this study is to generate a map of landslide vulnerability map by analysis of static natural factors with GIS. A simple and efficient algorithm is proposed to generate a landslide potentialities map from DEM and existing maps. The categories of controlling factors for landslides, aspect of slope, soil, vegetation are defined. The weight values for landslide potentialities are calculated from AHP method. Slope and slope-direction are extracted from DEM, and soil informations are extracted from digital soil map. Also, vegetation informations are extracted from digital vegetation map. Finally, as overlaying, landslide potentialities map is made out, and it is verified with landslide place.

• 한국콘텐츠학회논문지
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• 제2권3호
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• pp.41-58
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• 2002

본 연구는 정보기술 혁신 과정에 작용하는 환경, 기업, 기술 특성을 바탕으로 기업간 전자상거래 도입을 결정하는 요인을 고찰하였다. 분석 결과 기업간 전자상거래 도입기업과 미도입 기업을 유의하게 구분하는 요인은 거래당사자 영향력, 인지된 이익, 경영층 지원, 조직전략, 조직특성으로 나타났다. 따라서 기업에서 B2B EC가 성공적으로 도입되어 확신되기 위하여 B2B EC 도입기업과 미도입 기업의 차이를 구분하는 B2B EC 도입 결정요인을 충분히 반영하여 기업 전략을 수립해야 할 것이다.