• 전자공학회논문지
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• 제49권9호
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• pp.353-361
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• 2012

본 논문에서는 트림 T형 용접너트의 생산 시스템 중 불량품을 자동으로 선별할 수 있는 자동 비전 선별기의 성능 개선에 관한 방법을 제안한다. 자동 비전 선별기는 용접너트의 영상 신호에 대해 히스토그램을 활용한 경계 판별 및 나사산 검출, 이진 모폴로지 연산(Binary morphology operation)을 활용한 얼룩 검출 등의 기법을 활용한 것이다. 이 비전 선별기 운영에 있어 주된 문제는 컨베이어 벨트 상의 오일 등에 의한 오염에 따른 획득 영상의 화질 저하에 따른 오동작이다. 이를 해결하기 위해 배경 영상과 너트 영상의 구분을 위한 마스킹 기법을 사용하여, 너트 영상 부분에만 히스토그램 평준화를 이용하여 너트 영상부분의 대비를 높이는 전처리 과정을 도입하였다. 이를 통해 배경 부분에서 장비의 오염에 의해 추출되는 특징들의 영향을 없애고 획득 영상의 화질 저하에도 불구하고 오동작의 비율을 10 % 에서 0.2 % 로 낮출 수 있었다.

• Archives of Plastic Surgery
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• 제34권6호
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• pp.741-747
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• 2007

Purpose: In order to determine the differences in speech outcome based on timing of operation in submucous cleft palate, we have reviewed our experiences in the Furlow palatoplasty over the last 11 years. Methods: From March 1996 to March 2006, 38 submucous cleft palate patients received Furlow palatoplasty. 10 developmentally delayed patients were excluded and 5 patients were lost to follow up. The rest 23 patients were reviewed. Speech was evaluated preoperatively and postoperatively, and speech therapy was performed accordingly. Perceptual speech assessment included hypernasality, nasal emission and articulation disorder. Cinefluorography was performed to aid perceptual assessment. Based on timing of operation, the patients were divided into 3 groups as following: Group A under 24 months(8 patients), Group B from 25 to 48 months(6 patients), and Group C over 49 months (9 patients). Except 1 patient under speech therapy yet, resultant speech was compared. 200707Results: The rate of abnormal speech was higher in Group C(3/9, 33.3%) than in Group A(0%) or B(0%). All 3 patients who had been discontinued of speech therapy from the parent's judgment had abnormal speech. The reason for the discontinuation was that the regular speech therapy was a burden at school age. Any patients who had continued speech therapy had normal speech. Conclusion: The results of our study shows that operative timing is associated with speech development. Maintenance of speech therapy was an important factor for normal speech development. It will be helpful to perform a palatoplasty before 48 months of age to complete speech therapy before the school age.

• 한국항해항만학회지
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• 제42권5호
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• pp.311-316
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• 2018

IMO introduced the concept of e-Navigation and proposed MSPs(Maritime Service Portfolios) concept to reduce marine accidents, to improve efficiency of ship operation, port operation, and ship operation technology. Korean e-Navigation defines S1 ~ S5 services, as the service concept focused on domestic e-Navigation service corresponding to IMO MSPs, and is constructing a system as an ongoing project. S2 service (onboard system remote monitoring service) among the concepts of Korean e-Navigation services, is a service concept that judges the emergency level according to risk if an abnormal condition occurs during navigation, and provides corresponding guidance to accident ships based on emergency level. The purpose of this paper is to provide a basic architecture proposal of Korean e-Navigation S2 service navigation safety module, based on the S2 service operation concept. To do this, we conducted a questionnaire survey to ask experts with experience with sailors, to respond to the subjective risk experienced by sailors considering effects of anomalies, including equipment failure relative to sailing and navigational safety. Risk level for each abnormal condition was classified. The basic algorithm design of the navigation safety module is composed of safety index (SI) calculation module based on results of questionnaire and expert opinions, safety level (SL) determination module according to safety index, and corresponding guidance generation module according to safety level. To conduct basic validation of basic architecture of the navigation safety module, simulation of the ship anomaly monitoring was performed, and results have been revealed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.673-675
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• 1992

The operation of condenser-bank is now increasing around Kyoungin area. The operation of condenser-bank is used for the improvement of under voltage and expand of power demand. But the operation has the problem in itself as the switching over voltage. This report deals with the static-condenser fault caused by abnormal operation of circuit breaker which has occurred last summer. We have analyzed this fault using EMTP(electromagnetic transient program).

• Journal of Chest Surgery
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• 제15권1호
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• pp.129-135
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• 1982

Congenital pericardial defect is a rare anomaly, which was first described by M. Columbus in 1559. Four hundred years later the first clinical diagnosis was reported by Ellis et al. The congenital pericardial defect Is usually asymptomatic and Is found Incidentally at thoracotomy and autopsy, but it appears that partial absence of pericardium Is not Innocuous because of sudden death due to herniation of a portion of heart. We experienced congenital left pericardial defect in 20 year old female who was diagnosed as left ventricular aneurysm before operation. This patient complained of dyspnea on exertion and anterior chest discomfortness. Physical examination revealed Grade II pansystolic murmur on the 3rd and 4th intercostal space left sternal border. There were specific abnormal findings on the chest plain film, EKG, ultrasonography, and left ventriculography. On 9th July 1981, an operation was performed and found the left partial pericardial defect through which a large portion of left ventricle was herniated Into left pleural space. The method of operation was removal of adhesion and widening of the pericardial defect to avoid Incarceration. After operation, we observed marked Improvement of symptoms and disappearance of cardiac murmur.

• Smart Structures and Systems
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• 제6권9호
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• pp.1079-1105
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• 2010

Railway transport of goods and passengers is effective in terms of energy conservation and travel time savings. Safety and ride quality have become important issues as train speeds have increased. Due to increased speeds, minor damage to railway structures and abnormal interactions between trains and structures have given rise to increasingly serious accidents. Therefore, structural health and operational conditions must be monitored continuously in all service environments. Currently, various health and operation management systems are being developed and these are reducing both maintenance frequency and costs associated with disassembly. In this review, major damage and malfunctions and their locations are first analyzed based on numerous references. Then advanced train health and operation management technologies are classified into wayside detection methods and advanced integrated sensor methods and their operating principle and functions are reviewed and analyzed.

• 한국추진공학회지
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• 제21권5호
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• pp.61-70
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• 2017

고체 추진제를 연료로 사용하는 DACS의 강인한 추력 분배기법에 대한 연구를 수행하였다. 추진기관이 제어해야 하는 추력의 자유도보다 많은 구동 노즐을 보유한 시스템에 대하여, 비정상적인 상황을 허용할 수 있는 강인한 추력제어 기법을 제안하였다. 추력 분배기법에 의해 각 노즐로 인가된 명령 대비 응답 노즐 목 면적 크기의 차이를 이용하여 추력 분배기법에 적용된 가중행렬을 실시간으로 변환시키는 기법을 적용하였다. 이를 통하여 오차가 발생한 노즐의 추력 분배 비율을 감소시키고, 결론적으로 시스템에서 발생되는 추력 오차를 감소시키도록 하였다. 제안된 기법에 대하여 DCS와 ACS 각각의 구동장치가 제어명령을 추종하지 못하는 임의의 고장조건을 모의하였고, 시뮬레이션을 통해 기법의 성능을 검증하였다.

• 한국정밀공학회지
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• 제30권7호
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• pp.667-672
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• 2013

This paper presents the development of a condition monitoring system that monitors the operating conditions of a reduction unit, such as the bearing temperature, gearbox vibration, and gear oil deterioration, and notifies the operator of potential problems or abnormal conditions. A series of field tests on high-speed rail and conventional lines was performed to identify the characteristics of temperature rise and vibration levels on the reduction unit during operation. The monitoring system was designed based on the proper sensor selection, measurement method, and signal analysis to optimize the interface with the operating system of high-speed trains. Application of this monitoring system to high-speed trains will play an important role in their proper maintenance and safe operation.

• 한국정밀공학회지
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• 제18권10호
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• pp.101-108
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• 2001

In this study, the static and dynamic characteristics of endmilling process were modelled and the analytic realization of chatter mechanism was discussed. In this reward, We have discussed on the comparative assessment of recursive time series modeling algorithms that cal represent time machining process and detect the abnormal machining behaviors in precision endmilling operation. In this study, simulation and experimental works were performed to show the malfunctional behaviors. For this purpose, new recursive algorithm(RLSM) was adopted for the oil-line system identification and monitoring of a machining process, we can apply these new algorithms in real process for detection of abnormal chatter. Also, The stability lobe of chatter was analysed by varying parameter of cutting dynamics in regenerative chatter mechanics.

• 방사성폐기물학회지
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• 제20권4호
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• pp.511-521
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• 2022

Decommissioning of nuclear power plants generates a large amount of radioactive waste in a short period. Moreover, Radioactive waste has various forms including a large volumes of metal, concrete, and solid waste. The disposal of decommissioning waste using 200 L drums is inefficient in terms of economics, work efficiency, and radiation safety. Therefore, The Korea Radioactive Waste Agency is developing large containers for the packaging, transportation, and disposal of decommissioning waste. Assessing disposability considering the characteristics of the radioactive waste and facility, convenience of operation, and safety of workers is necessary. In this study, the exposure dose rate of workers during the disposal of new containers was evaluated using Monte Carlo N-Particle Transport code. Six normal and four abnormal scenarios were derived for the assessment of the dose rate in a near surface disposal facility operation. The results showed that the calculated dose rates in all normal scenarios were lower than the direct exposure dose limitation of workers in the safety analysis report. In abnormal scenarios, the work hours with dose rates below 20 mSv·y^-1 were calculated. The results of this study will be useful in establishing the optimal radiation work conditions.