• Journal of Chest Surgery
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• v.16 no.4
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• pp.444-451
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• 1983

Valve replacement in children and adolescents, aging below 20 years [Mean 15 years 4 months], has been done at Seoul National University Hospital from March 1977 to September 1982 . Seventy-Seven patients have received 91 artificial valves 4 prosthetic valves and 87 bioprosthetic valves. 63 patients had acquired valve lesions and 14 patients had congenital valve lesions. Among the patients with acquired valve lesion, 32 patients had the history of rheumatic fever. Seventy-five patients survived operation: 12 patients [ 15.6%] died within one month postoperatively and 3 patients [3.9%] during the follow-up period with the overall mortality rate of 19.5% Thromboembolic complication occurred in 3 patients with 2 deaths: 3.9% embolic rate or 3.74% emboli per patient-year. One patient who had been on coumadin anticoagulation died from cerebral hemorrhage. Actuarial survival rate was 77.6% at 1 years after surgery, after then there were no death.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1993.10a
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• pp.97-102
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• 1993

The application of epxy composite materials for the outdoor insulating systems has some significant advan-tages compared with conventional inorganic materials, that is low weight in combination with high mechanical strength, small dimensions and design versatility. The paper describes the results of high voltage investigations carried out different aging types of epoxy resin insulator and silicone grease coating. The insulators have been exposed 3000 hours to weather-o-meter and 12 months to outdoor. In this connection, the main study of paper is form the basis of develop-ment of principal technologies of epoxy composites which ard: (1)manufacturing of insulator, (2)high vol-tage testing under dry and wet condition, (3)mechani-cal properties, (4)accelerated weather-ometer test and outdoor exposed, artificial polution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.306-310
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• 1996

In this paper a series of developing process for an insulator which can be employed in overhead distribution lines, using polymeric composite materials, is introduced. In order to design an insulator for heavily polluted area, weathershed of alternating type was adopted, which could have longer leakage distance. Modified EVA was used as surface material which has good electrical and mechanical characteristics as well as superior chemical stability. FRP core was covered with above surface material through heat shrinking process. By standardization of each process, higher productivity and lower production cost could be ensured. The developed insulator has been put under various tests including long-term field test and artificial aging test and satisfactory results were obtained.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1740-1742
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• 1997

The trend of partial discharges(PD) magnitude which occured in a artificial void at cable joint is investigated as the function of a time. The results have shown that more than 500pC could be sustained for the considerable duration so the efficiency of monitoring a PD magnitude for diagnosing cable joints is confirmed. The other defects at cable joints are now under the same test, we can get the experimental data sooner or later.

• Smart Structures and Systems
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• v.5 no.4
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• pp.369-379
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• 2009

The sudden collapse of Interstate 35 Bridge in Minneapolis gave a wake-up call to US municipalities to re-evaluate aging bridges. In this situation, structural health monitoring (SHM) technology can provide the essential help needed for monitoring and maintaining the nation's infrastructure. Monitoring long span bridges such as cable-stayed bridges effectively requires the use of a large number of sensors. In this article, we introduce a probabilistic approach to identify optimal locations of sensors to enhance damage detection. Probability distribution functions are established using an artificial neural network trained using a priori knowledge of damage locations. The optimal number of sensors is identified using multi-objective optimization that simultaneously considers information entropy and sensor cost-objective functions. Luling Bridge, a cable-stayed bridge over the Mississippi River, is selected as a case study to demonstrate the efficiency of the proposed approach.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.141-144
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• 2017

4차 산업혁명 시대에 살고 있는 현대인들은 혼자 사는 1인 가구의 증가와 고령화 사회의 진입으로 인한 실버세대가 증가하는 추세이다. 외로움, 소외감, 우울증을 겪는 1인 가구 및 실버세대의 문제점을 해소시켜 주고 더 나아가 실버세대의 스마트폰 활성화를 위해 본 논문에서는 인공지능 기반 음성인식 기능을 탑재한 'Voice' 어플리케이션을 제안하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.551-554
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• 2017

The largest industry in the world is the medical industry, and due to aging and growing demand for well-being, it is necessary to review the competition strategy of the healthcare industry. We will secure competitiveness among medical institutions through the rapid dissemination of ICT convergence, study the intelligence level of digital health care by increasing the capacity of intelligent medical care by combining big data of medical data and artificial intelligence, And to find a countermeasure for constructing a medical optimization model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.81-82
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• 2018

The structure of the RC structure is actively reinforcing the structure of the building which has suffered from aging, artificial and natural damage of the building. Among various reinforcement methods, epoxy adhesive is used to attach FRP in FRP reinforcement method which is reinforcing by attaching FRP to the structural part. At this time, the epoxy adhesive having a low critical temperature has a sudden adhesive failure upon exposure to heat, and thus, the development of an inorganic fireproof adhesive having a high critical temperature has progressed. Therefore, in this study, the compositional change of inorganic fire - resistant adhesive exposed to high temperature heat was analyzed by XRD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.517-518
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• 2006

In this paper, to understand the effect of forest fires on polymer insulators for transmission lines, it was observed the aging of the housing surface of the polymer insulators. And, this paper shows the way how to create the artificial field testing in order to simulate forest fire. As the results of, maximum leakage current peaks by influence of flame increased from 1[mA] to 1.4[mA], and SEM results show the inorganic component on the housing surface because the organic component matters disappeared. Therefore, the case of exposed by forest fire, polymer insulator can be used in the early stage, but an exchange needs active countermeasure to be stabilize power delivery.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.331-332
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• 2023

With the aging of buildings, the number and importance of regular inspections of buildings are increasing. The current safety inspection goes through a procedure in which a skilled technician visits an old building, visually checks it, takes a photo, and finally organizes and judges it at the office. For this, field personnel and analysis and review personnel are required. Since the inspection procedure includes taking pictures, a huge amount of data has been accumulated from the time digital photos were used to the present. When a model that can check cracks outside a building is developed using these data, manpower and time required can be greatly reduced. Therefore, this study aims to create a model for classifying cracks that occur outside the building through the artificial intelligence method. The created model can be used as a basic model for determining cracks only by external photography in the future, and furthermore, it can be used as basic data for calculating the size and width of cracks.