• 한국전문물리치료학회지
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• 제16권1호
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• pp.42-51
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• 2009

The purpose of this study was to develop a checklist of risk factors for quantitative assessment of musculoskeletal complaints in shipbuilding workers. A key point was to develop comprehensive a checklist including the worker's physical ability, as ergonomic and workload factors. ln the first, through correlation analysis between musculoskeletal complaints and physical abilities in shipbuilding workers, risk factors related to physical abilities were selected. In the second, after the development of a checklist was composed of physical, ergonomic and workload factors, factor analysis was used to test the validity of the developed checklist. Each factors selected finally showed that physical factors were hand grip strength, spinal curvature, and flexibility (sit to reach), ergonomic factors were posture, total exposed time, duration, and force of working, and workload factors were physical and psychological workload perceived by worker. The results showed that musculoskeletal complaints was associated with physical abilities (p<.05). The developed checklist had a reliability of .761 (Cronbach=.761) and a validity and explanation of 54.9%. The criterion of management was classified in 4 stages by relative weights of each factor. It is suggested that active intervention is needed to reduce musculoskeletal complaints in workers with more than a 14.31 score.

• 공업화학
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• 제7권3호
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• pp.565-572
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• 1996

천연고무(NR), 부타디엔 고무(BR), 오일 투입량을 변량한 스티렌-부타디엔 고무(SBR)를 기본으로 하는 고무배합을 통하여 카본블랙의 최적 투입량에 대하여 연구하였다. 카본블랙의 최적 투입량은 Lee 이론을 기초하여 L 인자 값과 카본블랙의 부피비와의 상관 관계를 통하여 결정하였다. 그리고 얻어진 최적 투입량 값을 고무 물성 시험 결과를 통하여 재검증 하였다. 고무 종류별 카본블랙의 최적 투입량값은 각각 NR 60 phr, BR 57 phr, SBR-A 65 phr, SBR-B 70 phr, SBR-C 76 phr로 얻어졌다. 또한 오일의 함량을 20 phr씩 증가시킬때 마다 약 5phr 정도의 최적 투입량이 증가함을 관찰할 수 있었다. L 인자값을 통하여 얻어진 카본블랙의 최적 투입량은 인장강도와 가장 밀접한 관계가 있었으며 최대 인장강도 값을 갖는 카본블랙의 투입량 근처에서 형성되었다.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.289-298
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• 2007

The development of construction industry has led to the increase in the number of criteria imposed by project clients for selecting contractors. For example, clients often request tenderers to satisfy various conditions such as tight programme, financial strength, managerial ability, relevant work experiences, technical strength, high workmanship standard, safety requirement, quality specification, and yet others. This trend has attracted research interests of devising various methods for helping project clients to assess contractors' bids. For example, in recent development, the Works Bureau of the Hong Kong Government has introduced two mechanisms in tender evaluation for various public work contracts, namely, the Marking Scheme effective from June 2002 and the Formula Approach effective from November 2002 [1], [2]. These approaches evaluate a contractor's tender by considering collectively its tender price and performance attributes, the latter including contractor experience, past performance, technical resources and technical content of his proposal. The tender with the highest combined price and performance score (CPPS) will be normally recommended for acceptance. It appears, however, that there is little existing research in helping contractors to identify a competition strategy that enables the contractor to offer his most competitive bid collectively taking into account his resource capacities and project client's multiple performance criteria. This paper examines the factors affecting contractor's competition strategy to compete for works in Hong Kong. The understanding about the factors will contribute to identifying effective competition strategy. The data used for the analysis were collected from Hong Kong construction industry. The research findings may provide valuable references for investigating effective competition strategies in other construction industries outside the region.

• 한국건설순환자원학회논문집
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• 제9권4호
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• pp.578-584
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• 2021

본 연구에서는 매립회의 유효 활용을 위해 플라이애시(FA)와 매립회(PA) 4종의 수화반응 및 강도발현 특성을 비교 분석하였다. 해수 이동방식에 의해 염소함량 높은 PA는 시멘트 수화반응 촉진으로 FA와 비교하여 응결시간이 촉진되고, 누적 발열량이 증가하였으며, 초기 강도발현이 향상되었다. 그러나 재령 7일 이후 초기 수화물의 급격한 생성으로 활성도 지수 증가율은 감소하였다. 다량의 미연탄소 등 불순물을 함유한 PA는 낮은 수화 반응성으로 응결시간이 지연되고, 전 재령에서 강도가 저하되었다. 담수 이동방식에 의해 염소함량 낮고, 비정질량이 높은 PA는 FA와 유사한 수화반응 및 강도발현 특성을 나타냈다. 열중량 분석결과로 FA와 비슷한 수준의 Ca(OH)₂ 소비량과 포졸란 반응성을 가진 것을 확인하였다. 결과적으로 매립회의 활용성 높이기 위해서는 담수 이동방식의 적용 확대와 강열감량의 관리가 필요할 것으로 분석되었다.

• 한국학교보건학회지
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• 제5권1호
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• pp.111-119
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• 1992

The study examined the difference of the physique, the physical strength, and the physical constitution between meal and non-meal service schools at the countryside, and concluded as follows: 1) The effects on the physical development Meal service school student's height was 0.41~2.38cm taller, weight 0.21~1.58kg heavier, and the chests 0.15~2.55cm bigger than the non-meal service school students. Therefore, the effects of the school meal service on the student's physique development proved positive. 2) The effects on the physical strength Today, the student's physical growth is reinforced by consuming high calorie food, while their physical exercise is decreased. As a result, obesity becomes another problem. In this respect, physical strength is a significant factor in judging the physical condition of the students. This study compared the meal service schools with the non-meal service schools by suing six items of the physical strength test those schools. In comparison, the meal service school students were better than the others in most items except in the eleven year old girl's 100 meter running and the ball throwing, and the ten year old boy's 600meter running. It means that school meal service affects the physical growth in a positive manner. 3) The effects on the physical constitution The students in their growing period should have their meals not only balanced, but regularly since this helps to maintain their health. Insufficient nutrition may disturb the balanced physical growth of cause a weak or powerless physical constitution. As shown at the table 6, meal service school students who had a balanced meal have 0.01% lower incidence of disease. and 3.11~7.32% less myophia than the other. The average 0.39 to 0.63 cavity of the meal service school students also show that their constitutions are better than the non-meal service ones. In conclusion, the school meal service program gives every student a regular nutritious meal which results in a balanced physical growth. Erentually, the healthier students could be the healthier social menbers which promise a brighter society in the future.

• 대한환경공학회지
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• 제29권7호
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• pp.801-809
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• 2007

플라이 애쉬와 고로슬래그는 알칼리 활성화시 점착성의 시멘트성 물질로 전환될 수 있는 산업부산물로서, 이 같은 시멘트성 물질의 생산은 포틀랜드 시멘트 제조시보다 에너지 소비가 적고 이산화탄소 방출도 적다. 플라이 애쉬/슬래그 시멘트의 압축강도에 대한 알칼리 활성화 조건의 영향과 이 시멘트의 산 저항 특성을 평가하기 위해 실험을 수행하였다. 두 개의 알칼리 활성화 용액, 즉 수산화나트륨과 수산화나트륨 + 물유리가 사용되었다. 물유리 농도는 모든 실험에서 압축강도에 가장 큰 영향을 미치는 인자로 나타났다. 그 다음으로 중요한 인자는 수산화나트륨 농도와 양생 온도 순이었다. 황산과 염산에 대한 FC(플라이 애쉬 시멘트)와 FSC(플라이 애쉬/슬래그 시멘트)의 산 저항성은 포틀랜드 시멘트(PC)보다 월등히 좋았다.

• Archives of Pharmacal Research
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• 제28권11호
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• pp.1311-1316
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• 2005

To better define the relationship between dermal regeneration and wound contraction and scar formation, the effects of epidermal growth factor (EGF) loaded in collagen sponge matrix on the fibroblast cell proliferation rate and the dermal mechanical strength were investigated. Collagen sponges with acid-soluble fraction of pig skin were prepared and incorporated with EGF at 0, 4, and 8 $\mu$g/1.7 $cm^{2}$. Dermal fibroblasts were cultured to 80$\%$ confluence using DMEM, treated with the samples submerged, and the cell viability was estimated using MTT assay. A deep, $2^{nd}$ degree- burn of diameter 1 cm was prepared on the rabbit ear and the tested dressings were applied twice during the 15-day, post burn period. The processes of re-epithelialization and dermal regeneration were investigated until the complete wound closure day and histological analysis was performed with H-E staining. EGF increased the fibroblast cell proliferation rate. The histology showed well developed, weave-like collagen bundles and fibroblasts in EGF-treated wounds while open wounds showed irregular collagen bundles and impaired fibroblast growth. The breaking strength (944.1 $\pm$ 35.6 vs. 411.5 $\pm$ 57.0 Fmax, $gmm^{-2}$) and skin resilience (11.3 $\pm$ 1.4 vs. 6.5 $\pm$ 0.6 mJ/$mm^{2}$) were significantly increased with EGF­treated wounds as compared with open wounds, suggesting that EGF enhanced the dermal matrix formation and improved the wound mechanical strength. In conclusion, EGF-improved dermal matrix formation is related with a lower wound contraction rate. The impaired dermal regeneration observed in the open wounds could contribute to the formation of wound contraction and scar tissue development. An extraneous supply of EGF in the collagen dressing on deep, $2^{nd}$ degree-burns enhanced the dermal matrix formation.

• 한국항만경제학회지
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• 제35권3호
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• pp.125-150
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• 2019

훈춘지역은 지린성의 대외 개방 문호 및 창-지-투 지역의 유일한 개발개방선도구로 지역 물류의 발전에 중요한 거점 지역으로써 훈춘지역의 물류경쟁력을 촉진시키는 것은 동북지역 경제발전을 촉진시키는데는 중요한 요인이라고 할 수 있다. 이에 본 연구는 SWOT분석을 적용하여 훈춘지역의 물류경쟁력 활성화 요인을 도출하고, 중국과 한국물류전문가를 대상으로 AHP 설문조사를 통해 훈춘지역 물류경쟁력 활성화 요인의 우선순위를 도출함으로써 정책결정자에게 제시하는데 그 목적이 있다. 분석결과, 기회요인, 강점요인 순으로 가중치가 높게 나타났으며, 일대일로 정책 촉진 및 확대, 국가정책을 통한 적극적 지원, 국제물류센터도시의 건설, 물류중심지 건설, 대량화물 공급지 등의 요인 순으로 우선순위가 높게 제시되었다. 마지막으로, 종합적 관점에서 본 연구는 훈춘지역의 물류경쟁력 강화전략을 위해 훈춘지역이 가진 강점을 중심으로 한 SO전략(강점-기회전략)과 ST전략(강점-위협전략) 등 정책적 시사점을 제시하였다.

• 콘크리트학회논문집
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• 제15권1호
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• pp.87-94
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• 2003

현재 건설생산현장에서 이루어지고 있는 거푸집 제거 시기 결정, 설계기준강도 확보 등의 강도관리는 그 시점을 예측할 수 없다는 단점이 있기 때문에 건설생산현장에서의 공정계획 및 강도관리에서 한계가 있을 수밖에 없다. 이에 따라 콘크리트의 강도를 예측할 수 있으면 보다 합리적인 강도관리 및 공정계획이 가능하게 된다. 본 연구는 적산온도 방법에 의해 새로 제안된 강도예측모델의 적용가능성을 검증하기 위해 기존 강도예측모델 중 Logistic 모델과 비교 평가하였으며, 모의부재에서 채취한 코어공시체와 현장양생공시체의 압축강도를 비교 평가한 후 새로운 강도예측모델에 의해 강도를 예측하여 거푸집 제거시기를 결정하는 것에 대한 합리성을 검증하고자 하였다. 실험결과 Freiesleben의 활성화에너지를 이용한 등가재령함수에 있어서 콘크리트의 강도는 양생온도에 관계없이 유사한 강도수준을 나타내고 있으나 강도-적산온도의 상관성을 높이기 위해서는 등가재령 계산시 이용되는 활성화에너지에 대한 검토가 필요할 것으로 사료된다. 새로 제안된 모델의 경우 Logistic 모델에 비해 초기재령에 있어서 강도예측이 보다 정확한 것으로 나타났으며, SSE는 작고 결정계수는 높게 나타나고 있어 이를 이용한 강도예측이 보다 합리적일 것으로 판단된다. 본 연구의 범위 내에서 양생온도 10~15$^{\circ}C$의 경우 강도관리 측면에서 새로운 강도예측모델 사용시 압축강도 50kgf/${cm}^2$ 발현시점이 기존에 제안된 기간과 비교하여 빠르게 나타나고 있어 이를 건설생산현장에서 적용할 경우 거푸집제거시기의 단축에 의한 공기단축이 가능할 것으로 사료된다.

• 한국도로학회논문집
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• 제18권6호
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• pp.105-113
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• 2016

OBJECTIVES : This study is to develop the optimum mixing proportions for cement concrete pavement with using recycled aggregates. METHODS : The mixture varied recycled coarse aggregates content from 50 % to 100 % to replace the natural coarse aggregates by weight. Tests for fundamental properties as a cement concrete pavement were conducted before and after hardening of the concrete. RESULTS : It was found that the variation in the amount of the recycled aggregate affected the compressive and flexural strength development, as well as the chloride ion penetration resistance. As the amount of the recycled aggregate content increased the compressive and flexural strength and the resistance to chloride ion penetration decreased. However, the resistance to freeze-thaw reaction was affected significantly. In addition, the gradation of the aggregate became worse and hence so did the coarseness factor as the recycled aggregate amount increased. CONCLUSIONS : The fundamental properties of the concrete with recycled aggregate does not seem to be appropriate when the recycled aggregate quality is not guaranteed up to a some level and its replacement ratio is over 50%. The optimized gradation of the aggregates should also be sought when the recycled aggregate is used for the cement concrete pavement materials.