• 대한기계학회논문집A
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• 제25권12호
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• pp.2070-2077
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• 2001

An experimental investigation of the effect of composite patching repair was conducted to characterize the fatigue crack growth behavior in thick A16061-T6 (6mm) panels with single bonded patch by fiber reinforced composite patch. Four patch lengths and no patch plate were examined. An analytical procedure, involving three-dimensional finite element method having three layers to model cracked aluminum plate, epoxy by adhesive and composite Patch, is calculated the stress intensity factors. From the calculated stress intensity factors, the fatigue crack growth rates are obtained. At the single patching type, different fatigue crack growth ratios through the palate thickness were investigated by using the experimental and analytical results. The results demonstrated that there was a definite variation in fatigue life depending on the size of composite patch. While crack reached the patch end, retardation of crack growth was also revealed in the bonded repair.

• 한국건설관리학회논문집
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• 제3권4호
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• pp.123-131
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• 2002

공공 시설물별 특성을 반영하기 힘든 Incremental Budgeting 모델에 근거한 유지관리예산의 산정 및 배정은 유지관리 요구와 투자예산간의 관련성을 더욱 격리시켜, 시설물의 조기 노후화를 발생시키고 있다. Incremental Budgeting 모델의 문제점을 개선하기 위한 노력이 일부에서 진행되고 있으나, 기존 모델의 테두리에서 이루어져 근본적인 처방이라 보기 힘들다. 공공 시설물 유지관리예산모델의 해결방안은 새로운 시각에서 바라보아야 한다 이러한 관점에서 $50\%$ 이상이 80년대 이전에 축조되었으며, 최근 대형화$\cdot$현대화되는 추세인 국방시설을 대상으로 문헌연구와 전문가 면담조사를 통해 적합한 유지관리예산모델을 선정하고, 이에 따른 현행 업무프로세스를 개선하였다.

• Journal of Chest Surgery
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• 제32권11호
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• pp.1004-1008
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• 1999

Background: Total anomalous pulmonary venous return is a relatively rare disease which has a very high mortality(80% within a year) if not properly corrected surgically. Material and Method: Twenty-six infants with total anomalous pulmonary venous return underwent repair between May, 1991 and February, 1996. Result: There were 19 boys and 7 girls. The mean age at operation was 2.6 months(range: 5 day to 11 month) and the mean body weight was 4.3kg(range:2.8 to 6.7 kg). Preoperative stabilization included ventilator for 5 patients and inotropic support for 6 patients. There were 6 hospital mortalities. Significant risk factors of operative mortality were preoperative ventilator care(p<0.03) and preoperative inotropic support(p<0.05). Age, body weight at operation, pulmonary venous obstruction, high pulmonary arterial pressure, spurasystemic right ventricular pressure or emergency operation did not affected the operative outcome. Postperative pulmonary venous obstruction occurred in three patients 2 or 3 months later, among them one patient was reoperated. The actuarial survival was 76% at 40 months. Conclusion: Although early mortality was high, repair of total anomalous pulmonary venous return should be attempted in early life, but the patients receiving ventilator care or inotropic support need special attention.

• Journal of Chest Surgery
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• 제24권2호
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• pp.115-122
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• 1991

From April 1986 to December 1989, 25 infants under the age of 12 months with tetralogy of Fallot were operated on. Age ranged from 3 to 12 months[mean 8.9$\pm$4.9 months] and mean body weight was 7.8$\pm$ 2.6kg. All the patients were deeply cyanotic, 12 of them experienced anoxic spell. Transannular patch was laid down in 19 patients, in 7 of them monocuspid patch was utilized. Postrepair P RV/LV was measured at operation room in 17 patients[mean 0.48$\pm$0. 14]. Hospital mortality was 20Yo. Causes of deaths include right ventricular failure and low cardiac output. The mortality was closely related with patient`s age and body surface area at operation. Also higher mortality was noticed in patients having major associated anomaly or previous palliative operation, preoperative management with propranolol and transannular repair. 18 patients were followed up for 12 to 50 months with a mean follow-up time of 24 months after operation. There were no late deaths and late ventricular arrhythmia or congestive heart failure was not detected as yet. Redo operation was performed in one case because of residual pulmonic stenosis. Considering several advantages of early primary repair, primary repair of symptomatic infants with tetralogy of Fallot should be encouraged despite somewhat high mortality rate as yet and better results could be anticipated along with improvement of myocardial protection method and postoperative care.

• Composites Research
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• 제12권4호
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• pp.17-24
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• 1999

프리프레그 덧대기 방법을 이용하여 복합재료 쉘 구조물을 수리할 때 발생하는 잔류 변형을 고찰하기 위해서 유한요소해석과 실험을 수행하였다. 삼차원 응축 쉘 요소와 일차 전단변형 이론에 기초하여 유한요소 프로그램을 개발하였다. 자유 경계조건을 갖는 적층 쉘에 대한 해석결과를 프리프레그 덧대기 수리과정을 통해 측정된 변형률과 비교 검토하였다. 네 변이 고정된 적층 쉘을 프리프레그 덧대기로 수리할 경우 최종 잔류응력이 덧대기 부근에서 크게 발생하였다. 적층 쉘과 덧대기의 적층순서는 잔류응력에 크게 영향을 미치고, 또한 적층 쉘과 덧대기의 적층 순서가 동일해도 잔류응력이 발생하였다.

• 한국정보통신학회논문지
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• 제16권11호
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• pp.2557-2562
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• 2012

세포에서 질서를 유지하기 위해서는 유전정보에 대한 지속적인 감시와 회복체계를 필요로 한다. DNA는 염기쌍의 결합으로 이루어지는데, 틀린 염기쌍이 정상적인 염기쌍보다 훨씬 낮은 빈도로 형성되지만, 이것이 수정되지 않고 DNA내에 축적될 경우 세포가 죽기도 한다. 본 연구에서는 DNA 복제 시 발생하는 실수, 손상된 부분을 회복하는 DNA 복구 기능을 모사하여 공학적인 개념을 도입한다. 기존에 발표 되었던 부분을 보완하여 여러 군데에서 발생한 오류 위치를 찾아내고 복구시키는 효율적인 알고리즘을 제시한다.

• 산업기술연구
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• 제24권A호
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• pp.179-184
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• 2004

Each year, new technological advancements for repair-purpose are being introduced to overlay the old deterioration of RC bridge deck at highway by latex-modified concrete. The days may come when this old problem will be successfully resolved. While the experimental works and researches are very active at both laboratory and field, only a few theoretical studies were performed on interfacial problems, especially on stress distribution and concentration of RC beam overlayed by latex-modified concrete. The repaired and strengthened structures would induce a premature failure due to the stress concentration at the adhesive layer of different material before the design expected failure. This paper investigated and proposed an analytical model for predicting interfacial shear and normal stresses of RC beam repair-purpose overlayed by latex-modified concrete. This would be used for predicting interfacial stresses and preventing premature failure at interfaces. This study modified Smith-Teng method for applying to cementitious repairing material, which was based on a direct governing equation and linear-elastic approach for interfacial normal and shear stresses. The proposed theoretical model was verified using commercial FEA program, LUSAS, in terms of interfacial stresses predicted by the proposed model and calculated by LUSAS.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.286-289
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• 2004

본 연구는 영구임대주택을 대상으로 장기수선계획의 수선실태 조사와 전문가 인터뷰 결과를 바탕으로 장기수선계획의 문제점을 분석하는 것을 그 목적으로 한다. 이를 위하여 건축물 각 부위 부품의 수선주기 및 수선율을 조사하고 전문가를 대상으로 장기수선계획 및 시행에 대한 인터뷰를 실시하였다. 이와 같은 절차 및 방법에 따라 수행된 본 연구의 결과를 요약하면 다음과 같다. (1) 수선주기 도래 항목의 보수현황은 수선시기가 지났음에도 불구하고 보수율 평균이 $25\%$로 보수 및 교체가 미흡한 것으로 나타났다. (2) 장기수선계획은 영구임대주택 단지의 단지별 특성을 감안하지 못하고 일률적으로 적용되어있어 수선주기와 수선율이 부적절한 것으로 나타났다.

• 한국지진공학회논문집
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• 제22권5호
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• pp.291-298
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• 2018

Existing reinforced concrete building structures have seismic vulnerabilities under successive earthquakes (or mainshock-aftershock sequences) due to their inadequate column detailing, which leads to shear failure in the columns. To improve the shear capacity and ductility of the shear-critical columns, a fiber-reinforced polymer jacketing system has been widely used for seismic retrofit and repair. This study proposed a numerical modeling technique for damaged reinforced concrete columns repaired using the fiber-reinforced polymer jacketing system and validated the numerical responses with past experimental results. The column model well captured the experimental results in terms of lateral forces, stiffness, energy dissipation and failure modes. The proposed column modeling method enables to predict post-repair effects on structures initially damaged by mainshock.

• 수산경영론집
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• 제43권2호
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• pp.51-66
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• 2012

The purpose of this study is to present a new business performance model suitable for marin repair business. For this propose we have used survey datas gathered on several input and output factors from Marine engin repair companies Yeong-Do Gu. Gathering these the survey results we estimated the efficiency of each company through DEA method. The results of the analysis can be summarized as follows ; First, the result of the analysis showed 7 out of 24 DMU are not efficient companies. On the other hand 17 of them are efficient as the efficient output analyzes showed. Second, by analysing the results we could see significant differences between group companies, Ltd with a private companies with share on average efficiency in utilization. Third, two of the private companies are more effective and 6others were selected revisit and interview on the analysis. As a result inefficient DMU compared to efficient DMU and showed that they invest more on manpower in the field of sales and professional managers and techicians. Also, lots of effort devoted in order to standardize production by building capacity and environment management to improve welfare of the workers.