• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.94-103
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• 2018

The purpose of designing composite lattice structure which applied to launching vehicle and tactical missile body is to minimize the thickness and weight for applied load. It is usually made of carbon fiber; fabricating with filament winding process over silicon mold, and provided with a window opening for inspection purpose if necessary. In this paper compression test is conducted without window opening in lattice structure and preliminary FEA is carried out to confirm its accuracy. And then FEA is performed for the case of window opening to evaluate the soundness and the safety factor of the structure. We have calculated for two kinds of window shape; rectangular one and hexagonal one. And we have calculated safety factors of the lattice structure with window opening in every case based on failure strength of rib and knot with varying the thickness and location of the window for hexagonal shape. Through our investigation, we have found out the followings; (1) the hexagonal shaped window is shown higher safety factor than rectangular one, (2) a window in a certain location is shown higher safety factor than others, (3) although the soundness of window structure is improved as increasing its thickness, a window of a certain thickness is shown higher safety factor than others because of stress concentration.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.228-240
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• 2022

A comprehensive safety management system will be required in accordance with the implementation of the Major Disaster Punishment Act for close-up safety management of construction sites. Safety management level evaluation management requires a comprehensive relationship between safety management under the Construction Technology Promotion Act and health and health management system under the Industrial Safety and Health Act. Purpose: Safety under the Serious Accidents Punishment Act. The ultimate goal is to study the comprehensive analysis and relationship of health management and to improve the safety evaluation level of health and health management. Methods: The feasibility of the questionnaire was confirmed through the second Delphi analysis of construction site experts and safety managers, and the regression coefficient and path analysis of potential variants in safety management, safety management, health management and safety inspection were confirmed. Result and Conclusion: In the structural model, the regression coefficient (89%) from safety management, health system, and safety management to safety inspection execution and lambda values of appropriate observation variables were confirmed. In the path analysis, the total effect (.809) was confirmed by mediating health hygiene in the relationship between health plan establishment adequacy and post-inspection management, and the path coefficient (.82) of temporary structure safety was confirmed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.2
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• pp.12-17
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• 2017

Manned aircraft structural design is based on structural safety factor of 1.5, and this safety factor is equivalent to a probability of failure of between 10-2 and 10-3. The target failure probability of FARs is between 10-6 and 10-9 per flight according to aircraft type. NATO released STANAG 4703 to established the airworthiness requirements for small UAV which is less than 150kg. STANAG 4703 requires the Target Level of Safety according to MTOW. The requirements of failure probability for small UAV is between 10-4 and 10-5. In this paper, requirements of airworthiness certification for small UAV were investigated and the relationship of safety factors to the probability of structural failure is analyzed to reduce measure of safety factor and structural weight of unmanned aircraft.

• Journal of Ocean Engineering and Technology
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• v.16 no.1
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• pp.52-57
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• 2002

본 논문은 고온 고압의 유체를 수송하는 해저 파이프의 좌굴 현상에 대해서 논하였다. 고온 고압의 유체를 해저 파이프로 수송 할 때, 수송되는 고온 고압의 유체와 수위 해저의 온도와 압력들의 차에 의해서 유체 수송 파이프는 축 방향으로 압축력을 받게 되고 이 압축력을 견디지 못하면 수송 파이프는 수직 방향의 좌굴 현상이 발생하게 된다. 논문에서는 "semi-empirical design method"를 사용하여 수송 유체의 온도와 압력의 여러 가지 변화에 따라 파이프의 축 방향 압축력을 계산하고 수직 좌굴 현상에 따른 안전계수를 구하여 파이프의 초기 설계 결정에 도움을 주고자 했다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.3
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• pp.344-352
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• 1983

격납 용기 내에 비응축성 가스(공기)가 존재하는 경우에 증기의 응축 열전달 계수를 평가하는 방 법을 연구하였다. 유일한 대규모 격납 용기 실험인 CVTR자료를 이용하여 응축 열전달 계수를 계산하여, 현재 원자력 발전소의 냉각재 상실 사고(LOCA) 및 주 증기 배관 파열사고(MSLB)시에 격납 용기의 안전 해석에서 공식적으로 사용되고 있는 Tagami와 Uchida열전달 계수 관계식과 비교해 본 결과 좋은 일치를 보여 주었다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.17-20
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• 2021

본 연구는 인원 계수에 딥러닝 알고리즘을 적용한다. 인원 계수는 안전 관리 분야, 상업 분야에 적용될 수 있다. 예를 들어, 건물 내 화재 발생 시, 계수된 인원을 활용하여 인명 피해를 최소화할 수 있다. 다른 예로, 유동인구 데이터를 기반으로 상권을 분석하여 경제적 효율성을 극대화할 수 있다. 이처럼 인원 데이터의 중요성이 증가함에 따라 인원 계수 연구도 활발하다. 그 예로, 객체 탐지(Object Detection) 같은 딥러닝 기반 인원 계수, 센서 기반 인원 계수 등이 있다. 본 연구에선 딥러닝 알고리즘인 VGGNet을 사용하여 인원을 계수했다. 결과로 Mean Absolute Percentage Error(이하 MAPE)는 약 5.9%의 오차율을 보였다. 결과 확인 방법으로는 설명 가능한 인공지능(XAI) 알고리즘 중 하나인 Grad-CAM을 적용했다.

• Journal of Korean Society of Disaster and Security
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• v.8 no.1
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• pp.5-13
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• 2015

In this study, the lateral overflow discharge coefficients for the curvatures of side weir on meandering channel were analyzed. The side weir installed in accordance with the variation of the radius of curvature of the central angle bends with $180^{\circ}$. FLOW-3D model is applied to calculate the discharge coefficients of the side-weir on meandering and straight channels and the characteristics of the discharge coefficients are analysed. In order to verify the numerical model, the results from the hydraulic experiment conducted by the former research are compared with the results simulated by FLOW-3D in the same conditions. The discharge coefficients are calculated for the ratio between curvature ($R_c$) and channel width (b), and the ratio between over flow discharge of the straight channel ($Q_{wc}$) and the meandering channel ($Q_{wc}$) are compared. As the result, the discharge coefficients depend on the weir depth on upstream, and the radius of curvature, so that the discharge coefficients of side weir on the meandering channel can be estimated by them on the straight channel.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.397-398
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.471-472
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• 2016

• Computational Structural Engineering
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• v.10 no.3
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• pp.30-38
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• 1997

본 논문에서는 선형파괴역학의 관점에서의 파괴강도해석 기법들에 대해서 포괄적으로 논의하였다. 파괴강도해석을 위하여 규정되어야 할 파라메타들의 결정방법들에 대하여 설명하고 이들 파라메타들을 파괴강도설계에 적용시키는 과정들을 압력용기를 예를 들어 체계적으로 설명하였다. 선형파괴강도해석을 근간으로 한 파괴강도설계 방법으로 구조물을 설계하면 파괴응력에 대한 안전계수를 정확하게 산정할 수 있어서 안전성이 제고된 구조물을 설계.제작할 수 있게 될 것이다.