• 한국지반신소재학회논문집
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• 제17권3호
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• pp.1-8
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• 2018

모래다짐말뚝은 연약 지반에 조립질 재료로 채워진 말뚝 형태의 치환재료 시공을 통해 지반의 안정성을 확보하기 위한 목적으로 활용되는 지반개량 공법이다. 육상 및 해상의 연약지반 개량을 목적으로 꾸준히 사용되고 있는 모래다짐말뚝의 거동 특성은 지반 조건, 설치 방법 및 시공 형태에 따른 치환율 등에 의해 결정된다. 그러므로 모래다짐말뚝의 지지력 및 거동특성에 따른 안정성을 확보하기 위해서는 기존의 설계 식뿐만 아니라 시공 현장의 특성 및 영향 인자 등을 고려해 종합적으로 검토되어야 할 필요가 있다. 본 논문에서는 모래다짐말뚝 시공 중 예상치 못한 말뚝의 과다 변위가 발생한 국내 현장의 호안 축조 현장조건을 바탕으로 수치해석을 수행하고, 모래다짐말뚝의 치환율에 따른 지반의 변위 특성을 기존 제안식과 비교하였다. 해석결과 모래다짐말뚝의 치환율이 증가하여도 호안 구조물의 수평변위가 교대 말뚝 변위의 기준값을 초과할 수 있는 것으로 나타났으며, 이러한 지반 치환율에 따른 구조물의 거동 특성은 기존의 모래다짐말뚝 지지력 산정식에는 반영되지 못함을 확인하였다. 그러므로 모래다짐말뚝 시공 후에는 현장 시공성 확인을 병행하여 SCP 복합지반의 안정성을 검토해야 할 것으로 나타났다.

• 한국지반환경공학회 논문집
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• 제13권3호
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• pp.53-58
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• 2012

일반적으로 연약지반인 점성토 지반이나 느슨한 사질토 지반을 개량하기 위하여 모래다짐말뚝(SCP)공법 또는 쇄석다짐말뚝(GCP)공법이 쓰여지고 있다. 하지만 모래다짐공법은 모래의 수급부족과 모래채취로 인한 환경파괴와 같은 문제점이 있으며, 쇄석다짐공법은 쇄석다짐재료의 클로깅으로 인하여 배수재의 투수계수가 저하되는 문제점이 있다. 최근, 모래와 공학적 성질이 유사한 화력발전소 부산물인 저회를 모래의 대체 재료로 활용하기 위한 연구가 이루어지고 있다. 본 연구에서는 저회혼합다짐말뚝에 대한 기초적 연구로써 조립재료 및 치환율에 따른 조립재료 혼합다짐말뚝의 거동특성을 수치해석적으로 규명하였다. 특히, 말뚝중심부로부터 거리에 따른 침하저감비(SRR)를 산정하였다. 연구 결과는 다음과 같았다. 조립재료에 따른 혼합다짐말뚝의 침하저감비 변화값은 유사한 형태를 보였으며 치환율에 따라 복합지반의 강성이 증대하여 침하저감비는 감소하는 형태를 보였다. 특히, 치환율 20~40%의 범위에서는 일반적으로 침하저감비의 증가가 큰 것으로 나타났고, 치환율 40% 이상에서는 증가치가 서서히 감소하는것으로 나타났다. 본 연구에서 적용한 연약지반과 유사한 지반에 혼합다짐말뚝 적용 시 경제성을 고려하였을 때, 30~40%의 치환율이 적절할 것으로 사료된다.

• 대한방사선기술학회지:방사선기술과학
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• 제22권1호
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• pp.21-26
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• 1999

To make a comparative analysis for clinical application of total hip replacement arthroplasty(THRA) using fluoroscopy, we have performed total hip replacement arthroplasty making 30 patients an object with general radiography and fluoroscopy respectively. The results are as follows : 1) Reexamination rate was 80% of patients and mean 3.9 sheets in the general radiography, where as it was 46.7% and 0.37 sheets in the fluoroscopy(p<0.01) 2) Add examination was 2 cases in the general radiography, but fluoroscopy was no add examination. 3) The total film sheet used was mean 10.16 in the general radiography and 6.73 in the fluoroscopy. 4) In the cause of reexmination and add examination, inaccurate position of patient accounted for 72.6% in the general radiography and poor exposure condition accounted for 45.5% in the fluoroscopy. Total hip replacement arthroplasty using the fluoroscopy decreased reexamination and add examination rate, for these reasons, this method was effective abatement of pain, exposured radiation dose, and examination time and so on.

• 대한산업공학회지
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• 제41권2호
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• pp.150-161
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• 2015

This paper proposes a new approach to technology valuation, the market-replacement cost approach which integrates the cost-based approach and market-based approach. The proposed approach estimates the market-replacement cost of a target technology using R&D costs of similar R&D projects previously conducted. Similar R&D projects are extracted from project database based on document similarity between project proposals and technology description of the target technology. R&D costs of similar R&D projects are adjusted by mirroring the rate of technological obsolescence and inflation. Market-replacement cost of the technology is then derived by calculating the weighted average of adjusted costs and similarity values of similar R&D projects. A case of "Prevention method and system for the diffusion of mobile malicious code" is presented to illustrate the proposed approach.

• Journal of Chest Surgery
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• 제27권7호
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• pp.581-586
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• 1994

From February 1985 to February 1993, 18 operations were performed in 17 patients for treatment of aneurysmal disease [n=12] and/or dissection of the ascending aorta [n=6]. The ages ranged from 26 to 69 years [mean 44.3 $\pm$ 11.0 years].The proposed operations include composite graft replacement of aortic valve and ascending aorta with coronary reimplantation in 11, graft replacement of ascending aorta alone in 5, aortic valve replacement and supracoronary graft replacement in 1 and ascending aorta to abdominal aorta bypass with thromboexclusion of descending aorta in one patient. Both Bentall [n=6] and Cabrol [n=5] technique were utilized for reimplantation of coronary arteries.Concomitant replacement of aortic arch and arch vessel reconstruction was necessary in two patients. Hypothermic circulatory arrest was utilized in 6 patients. Recently, four patients were managed on warm blood continuous cardioplegia via retrograde route. There were no operative deaths. No significant postoperative complications were noted. Postoperative follow up was complete in 15 patients from 1 month to 72 months. Redo operation was necessary in one patient who had suffered from distal recurrence of dissection 5 years after successful Bentall operation. The other patients are all in excellent clinical condition. From our early experience with those 17 cases, we assume that satisfactory operative result could be achieved with a variety of surgical technique including hypothermic circulatory arrest. In addition, continuous perfusion of warm blood cardioplegia via retrograde route is supposed to be beneficial in selected cases.

• 성인간호학회지
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• 제18권2호
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• pp.183-193
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• 2006

Purpose: The purpose of the study was to test the effects of music therapy on postoperative pain in patients with total hip replacement. Method: The research design was a nonequivalent control group pretest-posttest design. The subjects were composed of thirty patients with total hip replacement. Fifteen of them were assigned to the experimental group and fifteen to the control group. Fifteen minutes tailored music therapy was given to the experimental group during five consecutive days. The instruments used for this study were pain NRS(numerical rating scale). The data were analyzed using percent, mean, standard deviation, ${\chi}^2-test$ and repeated measure ANOVA using SPSS WIN 11.0. Results: Hypothesis 1 "The score of pain NRS of experimental group will be lower than those of control group" was accepted(F=15.945, p<.001). Hypothesis 2 "The frequency of PCA analgesics of experimental group will be fewer than those of control group" was accepted (t=-2.312, p=.028). Hypothesis 3 "The vital signs(pulse, systolic BP and diastolic BP) of experimental group will be different from those of control group" was rejected. Conclusion: This music therapy can be recommended as an efficient nursing intervention to reduce postoperative pain in patients with total hip replacement.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.43-48
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• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3~4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.43-48
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• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzaolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3∼4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.143-144
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• 2020

For modern people who spend 80% of the day indoors, indoor air quality is an important factor in their lives. Radon and fine dust, which are indoor air quality pollutants, cause various diseases and lung diseases, so a method is needed to reduce them. Therefore, this study intends to utilize the air pollutant adsorption properties of the carbonized sludge by using the carbonized sludge generated through drying and carbonization of the sludge. As a result of the experiment, it was shown that the concentration of radon and fine dust gradually decreased as the replacement ratio of carbonized sludge increased. The reason is that the carbonized sludge has the ability to adsorb fine dust and radon, so it is considered that it gradually decreases as the replacement ratio increases. Also, the compressive strength and flexural strength tend to decrease gradually. The reason for this is that the carbonized sludge has a number of internal voids, and as the replacement ratio increases, the internal voids increase and the strength decreases. If the refinement and strength of the carbonized sludge replacement ratio are supplemented, it is believed that it will be able to replace the existing finishing materials.

• Advances in concrete construction
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• 제16권6호
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• pp.317-325
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• 2023

Strength prediction and correlation of concrete is done using experimental and analytical methods. Main objective is to correlate the experimental and simulated values of compressive strength of concrete mix using Fly Ash (FA) and Silica Fume (SF) by partial replacement of cement in concrete. Mix proportion was determined using IS method for M40grade concrete. Hundred and forty-seven cubes were cast and tested using Universal Testing Machine (UTM). Genetic Algorithm (GA) model was developed using C++ program to simulate the compressive strength of concrete for various proportions of FA and SF replacements individually at 3% increments. Experiments reveal that 12 percent silica fume replacement produced maximum compressive strength of 35.5 N/mm², 44.5 N/mm² and 54.8 N/mm² moreover 9 percent fly ash replacement produced a maximum strength of 31.9 N/mm², 37.6 N/mm² and 51.8 N/mm² during individual material replacement of concrete mix. Correlation coefficient for each curing period of fly ash and silica fume replaced mix were acquired using trend lines. The correlation coefficient is found to be approximately 0.9 in FA and SF replaced mix irrespective of the mix proportion and age of concrete. A higher and positive correlation was found between the experimental and simulated values irrespective of the curing period in all the replacements.