• 한국지리정보학회지
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• 제21권1호
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• pp.71-82
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• 2018

본 연구는 울산광역시를 대상으로 화학사고에 대비한 대피시설 위치의 적정성을 분석하여 피해 최소화를 위한 방안을 연구하였다. 연구방법은 화학물질 배출 및 이용량 자료와 인구센서스 집계구 자료, 대피시설 위치정보 등을 활용하여 화학사고 위험성 평가와 대피시설의 접근성을 분석하였다. 이를 통해 대피시설 위치의 적정성을 도출하였다. 화학사고 위험성은 석유화학공장과 인구가 밀집된 석유화학공단지역 인근 5km 이내에서 높았다. 대피시설은 대부분 화학사고 위험지역에 분포하고 있으나, 석유화학공장 인근지역에서 대피시설의 접근성이 취약한 것으로 나타났다. 따라서 우선적으로 화학사고 예방을 위해 노후화된 공장시설의 안전점검도 필요하지만, 대피시설의 수용인원, 규모 등을 고려하여 보다 효과적인 대피방안을 마련해야 될 것이다.

• Journal of Preventive Medicine and Public Health
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• 제41권6호
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• pp.413-418
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• 2008

Objectives: This study was performed to investigate the associations between the metabolic syndrome (MetS) and inflammatory markers. Methods: This cross-sectional analysis was performed using data from 1578 Koreans aged 40-69 years residing in a rural area. We investigated associations between MetS and circulating high sensitivity C-reactive protein (hs-CRP), white blood cells (WBC) and adiponectin. MetS was defined using the criteria proposed by the National Cholesterol Education Program Adult Treatment Panel III (ATP-III). Results: Increased WBC counts and hs-CRP levels and decreased adiponectin levels were observed in subjects with MetS. WBC, hs-CRP and adiponectin levels linearly deteriorated with an increase in the number of MetS components (all ptrend <0.005). Finally, adjusted odds ratios (ORs) for the risk of MetS by increase/decrease in 3 inflammatory markers were calculated by multivariate logistic regression analyses. In terms of changes in inflammation markers, in men, the adjusted ORs (95% confidence interval) were 1.15 (1.01-1.31) for WBC, 1.64 (1.02-2.64) for hs-CRP, and 0.19(0.08-0.45) for adiponectin, whereas corresponding adjusted ORs (95% Cls) in women were 1.27 (1.15-1.40), 0.98 (0.67-1.42), 0.09 (0.04-0.18), respectively. Conclusions: Serum adiponectin levels and WBC counts were found to be strongly associated with MetS in both sexes. However, hs-CRP lost its significance after adjusting for BMI and other inflammatory markers in women. This study shows that inflammatory response is associated with MetS in the Korean population. Further prospective studies are necessary to confirm the contribution made by inflammatory markers to the development of MetS.

• 열처리공학회지
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• 제23권4호
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• pp.191-197
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• 2010

Zr addition is known as effective method to improve the anisotropy of steel due to the elongated MnS inclusions which are observed in hot forged steels. The aim of this research is to investigate the effect of Zr addition on the mechanical properties and manganese sulphide morphology of 0.27%C-Cr-Mo plastic mold steel. The ingots were prepared by vacuum induction melting and forged to ${\Phi}35mm$ round bar. Forged bars were quenched and tempered at $560{\sim}640^{\circ}C$ for 1 hour. Jominy test, microstructual observation, tensile test and Charpy impact test were conducted. The morphology of MnS inclusions was changed by Zr addition. The shape of MnS inclusions was not so much lengthened and controlled not to be elongated by Zr inclusions which surround the MnS inclusions. Tensile strength and yield strength of the tempered steels were not nearly affected by the addition of Zr, but elongation and reduction of area were decreased. Especially, the toughness of Zr added steels was deteriorated with increasing of Zr content. From the results of this study, it is assumed that anisotropy of steels was improved by the addition of Zr. However, impact toughness of the steel was significantly decreased by the excessive Zr addition (over 0.066%).

• 제어로봇시스템학회논문지
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• 제20권6호
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• pp.676-688
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• 2014

The IEEE 802.11e EDCA (Enhanced Distributed Channel Access) mechanism has been proposed to improve the QoS (Quality of Service) of various services in WLANs (Wireless Local Area Networks). By differentiating the channel access delay depending on ACs (Access Categories), this mechanism can provide the relative service differentiation among ACs. In this paper, we consider that WLAN is deployed in medical environments to transfer medical traffic and we reveal that the quality of the medical traffic (in particular, ECG signals) is significantly deteriorated even with the service differentiation by IEEE 802.11e EDCA. Also, we analyze the reason for performance degradation and show that IEEE 802.11e EDCA has difficulty in protecting the transmission opportunity of high-priority traffic against low-priority traffic. In order to assure medical-grade QoS, we firstly define the service priority of medical traffic based on their characteristics and requirements, and then we propose the enhanced channel access scheme, referred to as DIFF-CW. The proposed scheme differentiates CW (Contention Window) depending on the service priority and modifies the channel access procedure for low-priority traffic. The simulation results confirm that the DIFF-CW scheme not only assures the QoS of medical traffic but also improves the overall channel utilization.

• 콘크리트학회논문집
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• 제15권3호
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• pp.377-385
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• 2003

인장강도와 내방식성이 우수하고 콘크리트 구조물속에서 철근과의 정착성이 양호하여 콘크리트 구조물의 새로운 보강재로 사용되고 있는 탄소격자섬유의 보강효과를 검증하기 위하여 탄소격자섬유보강공법으로 보강한 철근콘크리트 보 시험체를 제작하여 정적 휨 파괴실험을 통해 보강효과 및 휨 파괴특성을 분석하였다. 강판이나 탄소섬유 압착공법에서 나타나는 계면박리(탈락)파괴 보다는 보수 몰탈의 고강도화로 휨균열의 진전에 의해 콘크리트 속에서 철근에 정착된 격자섬유 층에서의 균열이 지점부로 진행되어 파괴되는 내부 계면박리와 지간중앙에서 철근 항복후 격자와 연결된 앵커볼트의 항복으로 인한 탄소격자섬유 파괴, 그리고 격자섬유 항복후 취성적인 콘크리트 압축파괴 양상이 나타났다. 실험결과를 근거로 최소보강재량이 제시되었으며, 강도설계법을 근거로 격자섬유로 보강시 필요한 설계법이 제안되었다.

• 한국환경생태학회지
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• 제7권2호
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• pp.241-251
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• 1994

덕유산 국립공원 등산로 및 야영장과 주변환경의 훼손에 대한 이용영향을 파악하기 위하여 4개의 주요 등산로와 덕유대야영장을 대상으로 1993년에 조사를 실시하였다. 등산로폭, 나지노출폭, 최대 깊이 및 등산로물매는 이용강도에 따른 차이가 인정되었다. 총 28km, 106개 조사지점에서 관찰된 훼손형태는 암석노출, 종침식, 뿌리노출등의 비율이 높았고 훼손된 지점의 등산로상태는 건전한 지점과 뚜렷한 차이를 나타내었다. 백련등산로가 가장 훼손이 심화되고 있으며 환경피해도 4등급 이상의 면적이 910$m^2$/km에 이르며 야영장에서도 이용압력과 훼손이 증가하고 있었다. 주연부의 상층 및 하층수관의 우점수종은 백련등산로에서 졸참나무 및 당단풍, 나머지 등산로에서는 모두 신갈나무 및 미역줄나무였으며, 이용강도의 차이가 있는 등산로간의 하층수종을 비교할 때 당단풍, 졸참나무, 개옻나무, 쇠물푸레나무, 조록싸리, 국수나무, 노린재나무 등이 이용영향에 대한 내성이 큰 수종으로 나타났다.

• 한국전산구조공학회논문집
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• 제28권5호
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• pp.563-570
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• 2015

기존 구조물의 손상평가에 관한 연구는 지진 등과 같은 과도한 하중에 의한 손상을 고려하였다. 그러나 구조물은 과도한 하중없이도 장기간의 시간에 따라 염화물, 탄성화 등과 같은 이유로 노후화가 진행되어 구조성능이 저하될 수 있다. 그래서 구조물의 건전도를 효과적으로 관리하기 위해서는 노후화에 의한 구조성능 저하도 검토되어야 한다. 본 연구에서는 염화물에 의한 철근의 부식을 노후화 요인으로 고려한다. 철근부식에 의한 재료의 구조성능 저하를 고려하기 위해 부식정도에 따른 철근의 단면적, 항복강도, 파단변형률, 피복 콘크리트 강도 등을 예측한다. 이를 구조모델링에 적용하여 구조부재 및 구조물의 구조성능 저하를 분석한다. 구조부재의 구조성능을 분석하기 위해 모멘트-곡률 해석을 수행한다. 구조물 레벨의 구조성능을 고려하기 위해, 고유치해석을 통한 고유주기와 모드형상을 분석한다. 또한 비선형 정적해석을 통해 구조물의 강도와 변형성능을 분석한다.

• 한국건축시공학회지
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• 제4권1호
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• pp.119-126
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• 2004

Generally, reinforced concrete is one of the most commonly used structural materials and it prevents corrosion of steel bar by high pH of interior, But, as time elapsed, reinforced concrete structure become deteriorated by many of combined deterioration factors and environmental conditions. And, there are large number of deteriorate mechanism of the reinforced concrete structure and it acts complexly. It is recognized that steel bar corrosion is the main distress behind the present concern regarding concrete durability. In this study, to institute combined deterioration environments, established acceleration condition and cycle for combined deterioration environments has a resemblance to environments which are real structures placed. After that to confirm corrosion properties of reinforced concrete due to permeability with covering depth and types of surface cover under combined deterioration environments, measured carbonation velocity coefficients, chloride ion diffusion coefficients, water absorption coefficients, air permeability coefficients and electric potential, corrosion area ratio, weight reduction, corrosion velocity of steel bar. The results showed that an increase in age also decrease carbonation velocity coefficients, increase Chloride ion diffusion coefficients and increases water absorption coefficients. As well, an increase in age also increases corrosion of steel bar. Data on the development of corrosion velocity of steel bar with types of surface cover made with none, organic B, organic A, inorganic B, and inorganic A is shown. As well, permeability and corrosion velocity of steel bar with covering depth is superior to 10mm than 20mm. And it is confirmed permeability and corrosion properties of steel bar are closely related.

• 한국환경복원기술학회지
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• 제17권1호
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• pp.147-162
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• 2014

This study aims to provide the biological and geographical materials to identify the changes in population of Family Ardeidae included Egretta alba modesta, Egretta garzetta, Bubulcus ibis, and Nycticorax nycticorax and establish their conservation measurement in terms of the fragmented and deteriorated habitat by human development such as housing and park projects. Wonjucheon Stream was measured the highest species diversity since the survey site was relatively less interfered by the surrounding human beings showing lower disturbance elements. However, the closer the stream comes downstream, the more the artificial disturbance elements generate, confirming that the species better adapted to contamination grow in more density so that the species composition becomes simplified. It implies that feeding place as well as breeding-growing places is also more closely related to the changes in population structure and species composition of Family Ardeidae. The results of Family Ardeidae immigration in Taejang-dong, Wonju, among the other survey sites, revealed that a total of 231 came to the site in 2006; and 210 in 2011, showing more or less reduction in the population. In the mean while, Namyang-dong in Hwaseong City showed the continuous decrease in population number of Family Ardeidae with 135 before development and 60 during development, resulting in the number never growing but continuously narrowing over and over after development. As a result of surveying the number of Family Ardeidae that bred following the findings above, Taejang-dong in Wonju City had 4 species of Family Ardeidae being bred, however, showing the decrease in number of population from 998 in 2006 to 589 in 2011. Namyang-dong in Hwaseong was confirmed to have as many as 352 of the population in 2006 and 230 in 2008; after the deforestation on their habitat, they had not lived in the site any longer, suggesting that the development would significantly affect Family Ardeidae.

• 한국구조물진단유지관리공학회 논문집
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• 제7권4호
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• pp.181-189
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• 2003

1960~70년대에 시작된 대도시 인구 집중화로 인해 다수의 조적조 건축물이 시공되었으며, 현재 이들은 상당수 구조 성능 저하 현상이 발생하고 있다. 노후 조적조 건축물의 특성 분석을 통해 벽체에서 발생하는 균열들이 가장 큰 열화요인이며 그 다음으로 큰 영향을 주는 요인은 기초로 분석되었으며, 열화 정도와 진행 속도는 사용유형, 시공년도와 큰 상관관계가 있는 것으로 분석되었다. 또한, 건물의 존치기간이 길어짐에 따라 전체적인 안전수준을 떨어지게 되는데 조적조 건축물에 있어서 열화 정도의 한계에 이르는 시기는 존치기간 30년으로 분석되었다.