• 한국항만경제학회지
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• 제33권4호
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• pp.117-134
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• 2017

본 연구는 12개 중국 수리조선 업체를 대상으로 DEA모형을 활용해 중국 수리조선산업의 효율성을 분석하고자 하였다. 기존 연구들과 달리 본 연구에서는 연구대상 뿐만 아니라 선정된 투입과 산출변수도 차별성을 지닌다. 연구대상은 수리조선시장에서 경쟁우위를 보이고 있는 중국의 업체를 대상으로 진행하였다. 효율성 분석을 위한 투입변수는 시설 외에 기술자 수를 고려하였으며, 산출변수는 매출액 외에도 수리선 척수 및 서비스 범위를 사용하여 관련 변수들을 다양화하였다. 분석에는 DEA모형에 의하여 시설만 투입변수로 한 경우 및 시설과 기술자 수를 투입변수로 하여 차이점을 분석하였다. 비효율적인 DMU의 경우, 효율적인 DMU가 될 수 있도록 참조집합을 통해 비효율성의 원인을 찾아 장단점을 분석하였다. 또한 국영기업과 민영기업을 구분해서 개선방안을 도출하였다.

• 대한안전경영과학회지
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• 제23권3호
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• pp.27-33
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• 2021

The purpose of this study is to present a novel indicator for analyzing machine failure based on its idle time and productivity. Existing machine repair plan was limited to machine experts from its manufacturing industries. This study evaluates the repair status of machines and extracts machines that need improvement. In this study, F-RPN was calculated using the etching process data provided by the 2018 PHM Data Challenge. Each S(S: Severity), O(O: Occurence), D(D: Detection) is divided into the idle time of the machine, the number of fault data, and the failure rate, respectively. The repair status of machine is quantified through the F-RPN calculated by multiplying S, O, and D. This study conducts a case study of machine in a semiconductor etching process. The process capability index has the disadvantage of not being able to divide the values outside the range. The performance of this index declines when the manufacturing process is under control, hereby introducing F-RPN to evaluate machine status that are difficult to distinguish by process capability index.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2862-2867
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• 2008

High-temperature components of gas turbine operated for certain period of time can be reused by being repaired or rejuvenated. In case of the gas turbine combustion liners, the biggest and the most important one in the high-temperature components, come in a repair shop after operated for 8,000 or 12,000 hours according to the model and go through the repair and rejuvenation in order to be reused. A stated combustion liner is the first channel which has the combustion gas reached a nozzle from a fuel nozzle. Materials and coating properties of old and new model combustion liners were investigated. To repair these components after the visual inspection, the coatings of combustion liners were removed and then FPI(Fluorescent Penetrant Inspection), a kind of the NDI(Non-Destructive Inspection), was conducted. Damage patterns and the number of the damaged components were classified and analyzed based on data provided from the visual inspection over a long period of time. Focusing on the difference between old model and new model combustion liners, we analyzed the damage distribution and changes and consequently concluded that new model combustion liner would increase repair rate.

• 자동차안전학회지
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• 제13권3호
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• pp.69-77
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• 2021

Although accident data from the National Police Agency and insurance companies do not know the vehicle safety, the damage level information can be obtained from the data managed by the bus credit association or the bus company itself. So the accident severity was analyzed based on the side impact accidents using accident repair cost. K-means clustering analysis separated the cost of accident repair into 'minor', 'moderate', 'severe', and 'very severe'. In addition, the side impact accident severity was analyzed by using an ordered logit model. As a result, it is appeared that the longer the repair period, the greater the impact on the severity of the side impact accident. Also, it is appeared that the higher the number of collision points, the greater the impact on the severity of the side impact accident. In addition, oblique collisions of the angle of impact were derived to affect the severity of the accident less than right angle collisions. Finally, the absence of opponent vehicle and large commercial vehicles involved accidents were shown to have less impact on the side impact accident severity than passenger cars.

• 산업경영시스템학회지
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• 제43권1호
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• pp.61-69
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• 2020

Systems such as database and socal network systems have been broadly used, and their unexpected failure, with great losses and sometimes a social confusion, has received attention in recent years. Therefore, it is an important issue to find optimal maintenance plans for such kind of systems from the points of system reliability and maintaining cost. However, it is difficult to maintain a system during its working cycle, since stopping works might incur users some troubles. From the above viewpoint, this paper discusses minimal repair maintenance policy with periodic replacement, while considering the random working cycles. The random working cycle and periodic replacement policies with minimal repair has been discussed in traditional literatures by usually analyzing cases for the nonstopping works. However, maintenance can be more conveniently done at discrete time and even during the working cycle in real applications. So, we propose that periodic replacement is planned at discrete times while considering the random working cycle, and moreover provide a model in which system, with a minimal repair at failures between replacements, is replaced at the minimum of discrete times KT and random cycles Y. The average cost rate model is used to determine the optimal number of periodic replacement.

• Clinics in Shoulder and Elbow
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• 제5권2호
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• pp.118-123
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• 2002

Purpose: The purpose was to identify the effectiveness of beach-chair position in the arthroscopic Bankart repair over conventional lateral decubitus position with distal traction. Materials & Methods: 36 arthroscopic Bankart repair through July 2000 to July 2001 was done under beach chair position. All cases were shoulder instability. Male patients were 6 and female were 4 with average age of 25 years. Arthroscopic suture anchor was used in 24 cases and average number was 3. Results: Interscalene block was tried in 29 patients and 1 case was changed to general anesthesia. Arthroscopic examination to identify Bankart lesion and associated pathology was done without difficulty Bankart lesions were easily reduced to anatomic position and placed suture anchor and hooking approprately. After the arthroscopic examination,3 cases were converted to open procedure without any positional change. Conclusion: Under interscalene block, the preparation was more simple and the patient could watch arthroscopic procedure with confidence. There was no hindrance in arthroscopic examination and arthroscopic repair could be dont: in more anatomic position. It can be easily changed to open repair if it needed

• Journal of Chest Surgery
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• 제50권4호
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• pp.263-269
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• 2017

Background: Endovascular aneurysm repair (EVAR) has dramatically changed the management of abdominal aortic aneurysms (AAAs) as the number of open aneurysm repairs have declined over time. This report compares AAA-related demographics, operative data, complications, and mortality after treatment by open aneurysm repair or EVAR. Methods: We retrospectively reviewed 136 patients with AAAs who were treated over an 8-year time period with open aneurysm repair or EVAR. Results: The mean age of the EVAR group was higher than that of the open repair group (p=0.001), and hospital mortality did not differ significantly between groups (p=0.360). However, overall survival was significantly lower in the EVAR group (p=0.033). Conclusion: Although EVAR is the primary treatment modality for elderly patients, it would be ideal to set slightly more stringent criteria within the anatomical guidelines contained in the instructions for use of the EVAR device when treating younger patients.

• Biomolecules & Therapeutics
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• 제19권3호
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• pp.282-287
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• 2011

Sirt1, a nicotinamide adenine dinucleotide ($NAD^+$)-dependent histone deacetylase, is known to deacetylate a number of proteins that are involved in various cellular pathways such as the stress response, apoptosis and cell growth. Modulation of the stress response by Sirtuin 1 (Sirt1) is achieved by the deacetylation of key proteins in a cellular pathway, and leads to a delay in the onset of cancer or aging. In particular, Sirt1 is known to play an important role in maintaining genomic stability, which may be strongly associated with a protective effect during tumorigenesis and during the onset of aging. In these studies, Sirt1 was generated in stably expressing cells and during the stimulation of DNA damage to examine whether it promotes survival. Sirt1 expressing cells facilitated the repair of DNA damage induced by either ionizing radiation (IR) or bleomycin (BLM) treatment. Fastened damaged DNA repair in Sirt1 expressing cells corresponded to prompt activation of Chk2 and ${\gamma}$-H2AX foci formation and promoted survival. Inhibition of Sirt1 enzymatic activity by a chemical inhibitor, nicotinamide (NIC), delayed DNA damage repair, indicating that promoted DNA damage repair by Sirt1 functions to induce survival when DNA damage occurs.

• 대한족부족관절학회지
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• 제5권1호
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• pp.5-12
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• 2001

Purpose: To find out the priority of which procedure has had a better outcome both clinically and radiographically between the two groups, one is treated by primary repair and the other by modified Brostr$\ddot{o}$m's procedure, by comparing the postoperative ankle joint stability and the patient's degree of satisfaction. Material and methods: 16 cases were taken into consideration whose number of severed ligaments were at least two or more of the lateral collateral ligaments of the ankle, and also were confirmed intraoperatively. Among them, 8 cases were treated with primary repair and the other 8 cases were treated with primary repair and the other 8 cases by modified Brostr$\ddot{o}$m's procedure. Results: There was no distinguishable difference for the patient's degree of satisfaction between the two procedures above mentioned. In 3 cases treated with primary repair, functional instability was observed. In case of postoperative ankle joint stability, 7 of 8 cases treated by modified Brostr$\ddot{o}$m's procedure has revealed increased joint stability. And 3 of 8 cases which were treated by primary repair have showed postoperative residual instability. Conclusion: Actually, the severed ligament can not maintain its normal strength though several months has elapsed, and possible residual instability could be remained. Therefore, it can be expected that modified Brostr$\ddot{o}$m's procedure also would be a .good method in obtaining suitable ankle joint stability as well as subtalar joint stability because of its reinforcement using extensor retinaculum.

• 한국건축시공학회지
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• 제10권6호
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• pp.97-107
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• 2010

누수균열은 상시 콘크리트 구조체의 거동, 물의 성분, 수압, 온도, 화학 물질 등 다양한 환경 요인의 영향이 작용함에 따라 이에 대응할 수 있는 성능을 확보한 보수재료 및 공법이 사용되어야 한다. 본 연구에서는 콘크리트 구조물은 국가적으로 유사한 공학적 특성(배합설계, 사용재료, 시공방법, 유지관리 등)을 가지고 있기 때문에, 누수균열에 대한 보수 접근도 크게 다르지 않을 것으로 보고, 향후 유지관리 전문가들의 공통적 기술 지침의 필요에 따라 자료를 개발하였다.