• 한국관개배수논문집
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• 제14권1호
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• pp.67-79
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• 2007

Concrete repair and reinforcement is a complex process, presenting unique challenges very different from those experience in the field of construction. The purpose of this study is to analyze the pattern and mechanism of deteriorations in irrigation and drainage structure. Damage and deteriorated structures are classified with several types. This provides a survey of crack repair methods, including a summary of the procedures that are being used. It is systematically evaluated with the disintegration on irrigation & drainage structure; drainage sluice gate, pumping station, drainage pumping station. Following the evaluation of the irrigation & drainage structure, a suitable repair and reinforcing procedure can be selected based on this report

• International Journal of Reliability and Applications
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• 제11권2호
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• pp.89-106
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• 2010

This paper deals with the reliability and availability characteristics of three different series system configurations with warm standby components and a repairable service station. The failure time of the primary and warm standby are assumed to be exponentially distributed with parameters ${\lambda}$ and ${\alpha}$ respectively. The repair time distribution of each server is also exponentially distributed with parameter ${\mu}$. The breakdown time and the repair time of the service station are also assumed exponentially distributed with parameters ${\gamma}$ and ${\beta}$ respectively. We derive the reliability dependent on time, availability dependent on time, the mean time to failure, $MTTF_i$, and the steady-state availability $A_i$(${\infty}$) for three configurations and perform comparisons. Comparisons are made for specific values of distribution parameters and of the cost of the components. The three configurations are ranked based on: $MTTF_i$, $A_i$(${\infty}$), and $C_i/B_i$ where $B_i$ is either $MTTF_i$ or $A_i$(${\infty}$).

• 한국수정란이식학회지
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• 제30권3호
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• pp.201-206
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• 2015

본 연구는 방사선 조사 후, 난소 적출을 한 흰쥐에 있어서 골회복과정 중에 셀레늄(Se)에 의한 보호 작용을 평가한 연구이다. 목적 수행을 위해 난소 적출술을 실시한 암컷 Sprague-Dawley계 흰쥐 80마리를 무작위로 ovariectomized(Ov), Ov/Se, Ov/irradiated(Irr) 그리고 Ov/Se/Irr와 같이 4개의 처리군으로 구분하였다. 골 결손은 난소적출(ovariectomy) 후, 40일에 모든 공시동물의 경골(tibia)에서 만들어졌다. 수술 후, 48시간에 Ov/Se군과 Ov/Se/Irr 처리구의 흰쥐에만 0.8 mg Se/kg을 투여하였다. 수술 후, 72시간에 Ov/Irr 군과 Ov/Se/Irr 처리구의 흰쥐에만 10Gy의 X-rays 조사를 사지부위(limb region)에 실시하였다. 수술 후, 모든 공시동물은 7, 15, 22 그리고 29일에 안락사를 시키고, 섬유주골형(trabecular bone)의 개수 분석(Masson Trichrome) 과 복 굴절 분석(Picrosirius)에 의해서 골 회복과정을 평가하였다. 난소적출한 군 및 방사선 조사한 군에서 골 재생 과정이 지연되는 현상을 확인이 가능하였다. 결론적으로, 셀렌산염 (sodium selenite)은 독성 없이 난소 적출을 한 흰쥐의 경골(tibia)의 골 재생과정에서 방사선 보호작용을 할 가능성을 제시하였다.

• 한국항공운항학회지
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• 제30권4호
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• pp.33-44
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• 2022

As the majority of Korean MRO demand is outsourced overseas, AMO by major foreign authorities is required to promote the Korean MRO industry to keep Korean MRO demand on shore. This study aims to promote consulting for AMO (obtaining repair station certification) by U.S. Federal Aviation Administration (FAA) for Korean maintenance companies. We analyzed AMO process, studied various industry cases, developed a model for AMO consulting, and identified core competencies for consultants. We suggested a five-step modified Milan model to apply AMO consulting process. We identified seven core competencies (ethics, communications, problem-solving, technical, relationship, resource management, organizational understanding) both social and technical for consultants. Additionally, we text analyzed more than 260 FAA AMO consultant resumes on Linkedin and interpreted frequent words (airline, audit, inspector, DER, regulation, ISO, system) to their competencies. This study contributes to promote consulting for the Korean MRO industry to be recognized by FAA and to develop the Korean MRO industry.

• 항공우주시스템공학회지
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• 제10권2호
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• pp.27-33
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• 2016

For the continued airworthiness of aviation products, aviation authority requires that every manufacturer should provide ICA(Instruction of Continued Airworthiness) to their users, and the users should follow it by themselves or using another approved maintenance agent. To reduce the cost and improve performance quality of maintenance activities, lots of users tries to outsource this job. To perform maintenance or repair of other owned air products, an air carrier and aviation maintenance companies should obtain AMO(approval of maintenance organization). It means AMO is a postulation to enter MRO(Maintenance Repair and Overhaul) market. For that, this paper discusses the comparison of requirements and procedures of AMO system between Korea and US to help understand the AMO system, and then, tries to point out what improvement should be made to Korean AMO system to be more effective, efficient and safe.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1999-2002
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• 2012

Background: DNA polymerase is a single-copy gene that is considered to be part of the DNA repair machinery in mammalian cells. The encoded enzyme is a key to the base excision repair (BER) pathway. It is evident that pol beta has mutations in various cancer samples, but little is known about ovarian cancer. Aim: Identification of any variant form of $pol{\beta}$ cDNA in ovarian carcinoma and determination of association between the polymorphism and ovarian cancer risk in Indian patients. We used 152 samples to isolate and perform RT-PCR and sequencing. Results: A variant of polymerase beta (deletion of exon 4-6 and 11-13, comprising of amino acid 63-123, and 208-304) is detected in heterozygous condition. The product size of this variant is 532 bp while wild type pol beta is 1 kb. Our study of association between the variant and the endometrioid type shows that it is a statistically significant factor for ovarian cancer [OR=31.9 (4.12-246.25) with p<0.001]. The association between variant and stage IV patients further indicated risk (${\chi}^2$ value of 29.7, and OR value 6.77 with 95% CI values 3.3-13.86). The correlation study also confirms the association data (Pearson correlation values for variant/stage IV and variant/endometrioid of 0.44 and 0.39). Conclusion: Individuals from this part of India with this type of variant may be at risk of stage IV, endometrioid type ovarian carcinoma.

• 교육시설 논문지
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• 제25권1호
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• pp.3-12
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• 2018

Educational facilities are more uncertain about maintenance costs due to their comprehensive and long life-cycle compared to commercial buildings. In addition, maintenance of the existing post management system can not maintain the original function of education facilities continuously and economically. In order to overcome this problem, it is necessary to analyze the repair and replacement cost for the uncertainty factor in maintenance. This study propose a model to determine repair and maintenance cost and cycle of educational facility based on probabilistic estimation concept. For the analysis, Monte Carlo simulation, a probabilistic analysis method, was applied based on the repair and maintenance history data of the educational facilities in Florida. The results of this study can be used as a guideline for quantitative facility management and facility management research.

• 한국경영과학회지
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• 제25권4호
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• pp.27-44
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• 2000

In this study we consider a spares provisioning problem for repairable items in which a parts inventory system is incorporated. If a machine fails, a replacement part must be obtained at the parts inventory system before the failed machine enters the repair center. The inventory policy adopted at the parts inventory system is the (S, Q) policy. Operating times of the machine before failure, ordering lead times and repair times are assumed to follow a two-stage Coxian distribution. For this system, we develop an approximation method to obtain the performance measures such as steady state probabilities of the number of machines at each station and the probability that a part will wait at the parts inventory system. For the analysis of the proposed system, we model the system as a closed queueing network and analyze it using a product-form approximation method. A recursive technique as well as an iterative procedure is used to analyze the sub-network. Numerical tests show that the approximation method provides fairly good estimation of the performance measures of interest.

• 한국관개배수논문집
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• 제18권2호
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• pp.142-160
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• 2011

This study was performed to apply the preventive management technique that is known for more economic and preventive for disaster than corrective technique to Repair & Improvement(R&I) Project policy of irrigational facilities. The appropriate periods of R&I Project had been driven to 40yrs, 24yrs, 27yrs, and 29yrs for reservoir, Pumping and drainage pumping station, Diversion weir and Irrigation & drainage canal respectively. The cost of R&I Project for 10 years had been estimated as 616.9 billion won per year including the 85 billion won for the project of 'Disaster prevention and Function continuity'. After the period of 'Improvement all at once', about 30yrs, 421.8 billion won was requested for 'Function continuity'.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.169-174
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• 2000

The analysis of irrigation water use characteristics from a pumping station is implemented. Sangjoo district was selected as a test area. Irrigation water are varied according to manners of water manager, weather change and irrigation system changes such as the repair and improvement of irrigation canal, installation of an auxiliary water sources and canal structure. From the results, average irrigation water is 1,136mm during irrigation period from 1987 to 1997 in sanjoo district. After improvement of irrigation district, irrigation water was increased 45% as average water use in this area.