• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1571-1584
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• 2023

In this study, a numerical analysis was performed as part of an international joint research project to reproduce a real cable tray fire that occurred in the heater bay area of the turbine building of a nuclear power plant. A sensitivity analysis was performed on various input parameters to derive results consistent with the sprinkler activation time obtained from the fire event analysis. For all sensitive parameters, the normalized sprinkler activation time correlated well with the power function of the normalized sprinkler height. A correlation equation was developed to identify the sprinkler activation time at any location when determining the slope or fire growth rate under the conditions assuming a linear or t-squared heat release rate (HRR) time curve. Various cable fire growth assumptions were used to determine which assumption was better to provide the prediction coincident with the information given from the fire event analysis in terms of the sprinkler activation time and total energy generated from cables damaged by fire. In the comprehensive analysis of all the sensitive parameters, the standard deviation of the input parameters increased as the sprinkler height decreased. Within the range of the sensitivity parameter values given in this study, when considering all sprinkler heights, the standard deviation of the cable model change was the largest and that of the overhang position change was the smallest.

• 한국군사과학기술학회지
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• 제21권5호
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• pp.563-571
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• 2018

In order to effectively protect a penetrator, the conically shaped protector was proposed and the protection capability was investigated. The collision and penetration of the penetrator with the protector were analyzed using dynamic finite element analysis. The post impact behaviors of the penetrator, i.e., flying velocity and the change of attitude angle, were monitored to investigate the protection capability. The flying velocity and the attitude angle are used to investigate the deviation and the penetration power respectively. The effect of rotation speed of the protector and the collision position on the protection capability is investigated in the viewpoint of deviation and attitude angle when penetrator colliding with our tank.

• 대한두개안면성형외과학회지
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• 제9권2호
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• pp.51-54
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• 2008

Purpose: The choice of open versus closed reduction for mandibular subcondylar fracture is a debatable issue. To evaluate the advantage of open approach to closed method with IMF(intermaxillary fixation), we conducted a retrospective study to compare the outcomes of each method. Methods: From 2002 to 2006, 29 patients with mandibular subcondylar fractures were treated by open or closed reduction. 17 patients were treated by open reduction and 12 patients by closed reduction and IMF. Each group was assessed for duration of mandibular immobilization, incidences of buccal palsy, malocclusion, TMJ(temporomandibular joint) pain, and deviation of the mandible on mouth opening. Results: All cases showed accurate reduction in anatomical position, no significant displacement and no deviation on mouth opening during the follow-up period. IMF period is statistically shorter in open reduction (p<0.05). Differences in incidence of other complications were not significant statistically. Conclusion: As there are significant independent morbidities associated with IMF which requires postoperative rehabilitation, prolonged temporomandibular immobilization should not be overlooked. Some patients with poor compliances will not tolerate IMF in nonsurgical treatment. In the aspect of patient's convenience and early recovery by short IMF period, open reduction would be recommended as a better treatment method.

• 한국ITS학회 논문지
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• 제20권5호
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• pp.186-201
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• 2021

자율 주행 기술이 발전함에 따라 주행 주변 환경을 인식하는 데 차량 위치의 정확성은 매우 중요하다. 측위의 정확도를 높이기 위해 정밀지도를 사용한 지도 정합 측위기술(map-matching localization)이 연구되고 있다. 기존의 지도 정합 기법은 지도에서 차선의 중심으로 표현된 데이터를 기반으로 차량 위치를 추정하기에 차선 내 측면 거리의 편차를 반영하지 않는다. 따라서 본 논문에서는 정밀한 측위를 제공하기 위해 영상처리를 통한 차선 검출 기법과 정밀지도의 차선 위치 정보를 이용한 기법을 제안한다. 영상 처리 기법으로 IPM(inverse perspective mapping)과 다중 차선 검출 기법, 중앙선 검출 기법을 통하여 차선 번호를 검출하고 차선 이탈 감지 방법으로 차선 중심으로부터 차량의 측면 거리를 추정한다. 최종적으로 영상처리로 검출한 차선 번호와 GNSS / INS의 위치를 기반으로 정밀지도에서 위치 링크정보를 추출하고 추출된 링크에 측면 거리를 반영하여 차선 내 차량의 위치를 추정한다. 제안된 방법의 성능을 평가하기 위하여 실제 도로에서 실험하였다. 제안하는 방법은 GNSS / INS와 비교 시 약 1.0m 정도 정확도가 개선되며, 기존의 차선레벨 맵매칭 방법과 비교 시 구간별로 약 0.04m ~ 0.21m(7~30%) 정확도가 개선됨을 확인하였다.

• 한방안이비인후피부과학회지
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• 제17권3호
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• pp.126-130
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• 2004

Oculomotor nerve palsy presents itself with sudden onset unilateral ptosis and inability to turn the eye upward, downward, or inward, which causes visual disturbances. Strabismus caused oculomotor nerve palsy refers to muscle imbalance that results in improper alignment of the visual axes of the two eyes It may be divided into paralytic and non paralytic strabismus. paralytic strabismus is primarily a neurologic problem. Characteristic clinical disturbances result from lesions of the third, fourth, and sixth cranial nerves. Lesions of the third nerve result in a paralysis of lateral or outward movement and a crossing of the visual axes. Objective: This study was designed to evaluate the effects of oriental medicine therapy on a peripheral oculomotor nerve palsy. Methods & Result: The clinical data was analyzed on a patient with oculomotor nerve palsy whose main symptoms were right side ptosis and inability to turn the eye inward. The patient was treated by the electroacupucture(4Hz frequency, intensity was adjusted so that localized muscle contractions could be seen). As the result, symptoms are improved remarkably. Conclusion: The patient showed right eye ptosis and unilateral deviation of the right eye ball in neutral position. After acupuncture treatment and electroacupuncture treatment, the ptosis and deviation of the patient's right eye was recovered six weeks after the onset. The study suggests that oriental medicine therapy is significantly effective on the treatment of peripheral oculomotor nerve palsy.

• Advances in aircraft and spacecraft science
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• 제3권4호
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• pp.471-502
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• 2016

This paper presents the dynamic instability analysis of un-damped elastically supported piezoelectric functionally graded (FG) beams subjected to in-plane static and dynamic periodic thermomechanical loadings with uncertain system properties. The elastic foundation model is assumed as one parameter Pasternak foundation with Winkler cubic nonlinearity. The piezoelectric FG beam is subjected to non-uniform temperature distribution with temperature dependent material properties. The Young's modulus and Poison's ratio of ceramic, metal and piezoelectric, density of respective ceramic and metal, volume fraction exponent and foundation parameters are taken as uncertain system properties. The basic nonlinear formulation of the beam is based on higher order shear deformation theory (HSDT) with von-Karman strain kinematics. The governing deterministic static and dynamic random instability equation and regions is solved by Bolotin's approach with Newmark's time integration method combined with first order perturbation technique (FOPT). Typical numerical results in terms of the mean and standard deviation of dynamic instability analysis are presented to examine the effect of slenderness ratios, volume fraction exponents, foundation parameters, amplitude ratios, temperature increments and position of piezoelectric layers by changing the random system properties. The correctness of the present stochastic model is examined by comparing the results with direct Monte Caro simulation (MCS).

• 대한의용생체공학회:의공학회지
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• 제17권3호
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• pp.365-372
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• 1996

The researches to acquire diagnostic parameters from ultrasonic images are advanced with the progress of the digital image processing technique. Especially, the detection of endocardial boundary is very important in ultrasonic images, because endocardial boundary is used as a clinical parameter to estimate both the cardiac area and the variation of cardiac volume. Various methods to detect cardiac boundary are proposed, but these are insufficient to detect boundary. In this paper, an algorithm that detects the endocardial boundary, expanding the cavity region from the center using statistical information, is proposed The value of mean and sty:nd, wd deviation in cavity region is lower than those in muscle re- gion. Therefore, if we define the multiplication of mean and standard deviation as homogeneous coefficient, it can lead to conclusion that the pixels with small variation of these coefficleno are cavity region, and extraction of endocardial boundary from cavity region is possible. The proposed method detected endocardial boundary more effectively than edge based or threshold based method and is robuster to noise than radial searching method that has high dependency for center position.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.518-523
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• 2007

Purpose: The purpose of this study is to prove that orthognatic surgery on asymmetric prognathism patients improve the temporomandibular dysfunction. Materials and methods: All 30 patients underwent mandibular setback with B-SSRO including 22 patients Le Fort I surgery in KyungHee medical center. Preoperative and postoperative PA cephalograms & transcranial radiographs were measured midline deviation in Mx and Mn, occlusal canting change, condyle position, the temporomandibular dysfunction were checked before surgery, within 1 month after surgery, $3{\sim}6$ months, 12-24 months after surgery respectively. Results: The temporomandibular dysfunction were relieved after surgery in 17 patients of 25 patients. Conclusion: Orthognatic surgery may benefit the temporomandibular joint dysfunction in facial asymmetry patients by obtaining a postoperative stable occlusion and better physiologic neuromuscular function. Specially impovement of occlusal canting may reduce condyle displacement of midline deviation side and the temporomandibular joint dysfunction.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.480-488
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• 2020

This study was conducted to improve the flow uniformity inside the chip tester through changing the flow path formation according to the inlet and outlet position of chamber. The internal flow and velocity distributions of the modified chamber models (Cases 1-3) were compared with the reference chamber model through three-dimensional Reynolds-averaged Navier-Stokes equations with k-ε turbulence model. The modified chamber models showed the superior flow uniformity characteristics compared to the reference chamber model. To investigate the flow uniformity in the chip tester, the standard deviation of the velocity was defined and compared. Through the internal flow analysis and assesment of the standard deviation, Case 2 among the test cases including the reference model showed the best flow uniformity generally.

• 전력전자학회논문지
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• 제16권1호
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• pp.71-78
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• 2011

본 논문에서는 영구자석 동기 전동기의 센서리스 운전에 있어, 제어에 사용되는 제정수의 오차가 각도 추정 성능에 미치는 영향을 분석하였다. 회전 자속의 위치를 추정하는데 사용되는 위치 오차 정보를 부호 요인과 이득 요인으로 나누어, 그 중에 각도 추정의 편차를 초래하는 부호 요인을 중심으로 제정수 오차가 각도 추정 성능에 미치는 영향을 분석하였다. 본 논문에서는 센서리스 제어에 사용되는 저항과 인덕턴스의 오차로 표현되는 각도 추정 편차의 함수를 수식적으로 도출하였고, 모의실험 및 실험을 통해 도출된 수식의 타당성을 검증하였다.