• 한국안전학회지
• /
• 제26권1호
• /
• pp.36-42
• /
• 2011

This paper presents a nonlinear soil-structure interaction analysis approach, which can consider precisely characteristics of structures, complicated soil profiles and nonlinear characteristics of soil. Although many methods have been developed to deal with the soil-structure interaction effects in past years, most of them are nearly unpractical since it is difficult to model complicated characteristics of structure and soil precisely. The presented approach overcomes the difficulties by adopting an maligned mesh generation approach and multi-linear model. The applicability of the proposed approach is validated and the effects of complicated characteristics of structure and soil on soil-structure interaction are investigated through the numerical example by the proposed nonlinear soil-structure interaction analysis approach.

• 시스템엔지니어링학술지
• /
• 제19권2호
• /
• pp.46-58
• /
• 2023

Deterministic safety analysis is a crucial part of safety assessment, particularly when it comes to demonstrating the safety of nuclear power plant designs. The traditional approach to deterministic safety analysis models is to model the nuclear core using point kinetics. However, this simplified approach does not fully reflect the real core behavior with proper moderator and fuel reactivity feedbacks during the transient. The use of Multi-Physics approach allows more precise simulation reflecting the inherent three-dimensionality (3D) of the problem by representing the detailed 3D core, with instantaneous updates of feedback mechanisms due to changes of important reactivity parameters like fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC). This paper addresses a CEA ejection accident at hot full power (HFP), in which the underlying strong and un-symmetric feedback between thermal-hydraulics and reactor kinetics exist. For this purpose, a multi-physics analysis tool has been selected with the nodal kinetics code, 3DKIN, implicitly coupled to the thermal-hydraulic code, RELAP5, for real-time communication and data exchange. This coupled approach enables high fidelity three-dimensional simulation and is therefore especially relevant to reactivity initiated accident (RIA) scenarios and power distribution anomalies with strong feedback mechanisms and/or un-symmetrical characteristics as in the CEA ejection accident. The Systems Engineering approach is employed to provide guidance in developing the work in a systematic and efficient fashion.

• 한국정보통신학회논문지
• /
• 제10권1호
• /
• pp.206-211
• /
• 2006

수량화 문제는 n개의 성질을 갖는 m개의 개체들을 각 개체들의 유사도(similarity)를 가장 잘 반영하도록 p차원의 공간 상에 대응시키는 문제이다. 본 논문에서는 물리학에서의 열평형 상태(thermal equilibrium state)에서 분자시스템의 해석적 근사 움직임에 대한 이론인 평균장 이론(mean field theory)에 의한 분자의 평균 변화량 계산과 어닐링(annealing) 방법에 의한 평균장 신경회로망(mean field neural network)을 수량화 문제(quantification analysis problem)의 해결에 적용하였다. 그 결과, 제안한 최적화 응용기법 이 기존의 고유치 분석방법(eigen value analysis)에 비해 비용측면에서 좀 더 최적에 가까운 해답을 찾아낼 수 있음을 확인하였다.

• 한국항행학회논문지
• /
• 제25권1호
• /
• pp.52-59
• /
• 2021

IATA (International Air Transport Assosiation)의 운송용 항공기 사고 집계에 의하면, 사고 건의 61%가 비행의 접근 및 착륙단계에서 발생 되었으며, 이중 항공기의 불안정한 접근으로 인한 사고가 16%인 것으로 파악되었다. 이는 조종사의 불안정한 접근 및 수정 조작 미흡에 따른 복행을 시행하지 않고, 무리하게 접근을 지속하여 사고로 이어진 것으로 식별되었다. 불안정 접근의 원인으로는 공항의 접근 절차, 조종사의 실수, 잘못된 계획, 업무 부하 (workload), ATC (Air Traffic Control) 혼잡 등 다양하게 있을 수 있다. 본 연구에서는 비행 데이터 분석 시스템을 활용하여, 불안정 접근 이벤트가 반복해서 발생하는 국내의 사례 공항과 기종을 선정하여, 주요 발생 이벤트, 공항 접근 절차, 조종사의 조작 뿐만이 아니라 공항의 기상, 지리적 여건 등 다양한 환경적 요인을 포함한 비행 데이터 분석을 통해 불안정 접근 이벤트의 경향성과 발생 원인 및 위험 요소를 식별하고 제거하여 불안정 접근 이벤트의 경감조치 및 항행 안전 증진 방안 마련의 시사점을 도출하고자 한다.

• Structural Engineering and Mechanics
• /
• 제21권4호
• /
• pp.423-435
• /
• 2005

A modal approach is proposed for dynamic analysis of concrete arch dam-reservoir systems in frequency domain. The technique relies on mode shapes extracted by considering the symmetric parts of total mass and stiffness matrices. Based on this method, a previously developed program is modified, and the response of Morrow Point arch dam is studied for various conditions. The method is proved to be very effective and it is an extremely convenient modal technique for dynamic analysis of concrete arch dams.

• Earthquakes and Structures
• /
• 제12권6호
• /
• pp.653-663
• /
• 2017

A seismic margin assessment evaluates how much margin exists for the system under beyond design basis earthquake events. Specifically, the seismic margin for the entire system is evaluated by utilizing a systems analysis based on the sub-system and component seismic fragility data. Each seismic fragility curve is obtained by using empirical, experimental, and/or numerical simulation data. The systems analysis is generally performed by employing a fault tree analysis. However, the current practice has clear limitations in that it cannot deal with the uncertainties of basic components and accommodate the newly observed data. Therefore, in this paper, we present a Bayesian-based seismic margin assessment that is conducted using seismic fragility data and fault tree analysis including Bayesian inference. This proposed approach is first applied to the pooltype nuclear research reactor system for the quantitative evaluation of the seismic margin. The results show that the applied approach can allow updating by considering the newly available data/information at any level of the fault tree, and can identify critical scenarios modified due to new information. Also, given the seismic hazard information, this approach is further extended to the real-time risk evaluation. Thus, the proposed approach can finally be expected to solve the fundamental restrictions of the current method.

• Journal of the Korean Data Analysis Society
• /
• 제20권6호
• /
• pp.3049-3067
• /
• 2018

최근 조직몰입(organizational commitment) 3요인(정서적 몰입, 규범적 몰입, 지속적 몰입) 모델(Allen, Meyer, 1990, 1991) 관련 연구에서 사람중심 접근법(person-centered approach)이 많은 관심을 받고 있지만 아직 국내 연구자들에게는 크게 확산되지 못하고 있다. 이에 본 논문은 사람중심 접근법의 개념과 관련 자료분석 방법을 군집분석(cluster analysis)과 잠재프로파일분석(latent profile analysis)을 중심으로 소개하고자 한다. 또한 이러한 방법들의 실제 적용 사례를 제시하기 위해 국내 직장인들 349명으로부터 수집한 자료를 바탕으로 군집분석과 잠재프로파일분석을 각각 실행하여 각 분석으로부터 6개의 조직몰입 프로파일 유형들을 도출하였으며 그 결과를 비교하였다. 뿐만 아니라, 조직몰입 프로파일 유형 간 이직의도(turnover intention)의 차이를 살펴봄으로써 도출된 프로파일의 타당성을 확인하였다. 본 논문은 조직몰입에 대한 기존의 변수중심 접근법(variable-centered approach)에 대한 보완적 방법으로 사람중심 접근법이 갖는 의미를 이해하고, 나아가 국내 직장인들의 조직몰입 프로파일 유형을 살펴볼 수 있다는 점에서 국내 연구자들 뿐만 아니라 실무담당자들에게 시사하는 바가 크다고 할 수 있다.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1994년도 추계학술발표회 및 정기총회
• /
• pp.12-12
• /
• 1994

Simulation output knowledge analysis is one of problem-solving and/or knowledge adquistion process by investgating the system behavior under study through simulation . This paper describes an approach to simulation outputknowldege analysis using fuzzy neural network model. A fuzzy neral network model is designed with fuzzy setsand membership functions for variables of simulation model. The relationship between input parameters and output performances of simulation model is captured as system behavior knowlege in a fuzzy neural networkmodel by training examples form simulation exepreiments. Backpropagation learning algorithms is used to encode the knowledge. The knowledge is utilized to solve problem through simulation such as system performance prodiction and goal-directed analysis. For explicit knowledge acquisition, production rules are extracted from the implicit neural network knowledge. These rules may assit in explaining the simulation results and providing knowledge base for an expert system. This approach thus enablesboth symbolic and numeric reasoning to solve problem througth simulation . We applied this approach to the design problem of broadband communication network.

• 한국문헌정보학회지
• /
• 제56권4호
• /
• pp.269-284
• /
• 2022

Exploring research similarity of researchers offers insight on research communities and potential interactions among scholars. While co-authorship is a popular measure for studying research similarity of researchers, it cannot provide insight on authors who have not collaborated yet. In this work, we present novel approach to capture research similarity of authors using citation information. Extensive study is conducted on DATA & KNOWLEDGE ENGINEERING (DKE) publications to demonstrate and compare suggested approach with co-authorship based approach. Analysis result shows that proposed approach distinguishes author relationships that is not shown in co-authorship network.

• Journal of Veterinary Science
• /
• 제24권1호
• /
• pp.12.1-12.10
• /
• 2023

Background: Arthroscopic exploration of ventromedial part of canine coxofemoral joint is limited in conventional dorsal approach. Objectives: We evaluated the efficacy of a medial arthroscopic approach to the coxofemoral joint of dogs by analyzing the joint visible area and performing a safety analysis. Methods: Arthroscopic approaches to the coxofemoral joint were made in five cadavers using a traditional (dorsal) and novel (medial) approach. Three observers scored the visible area of images and videos of the acetabulum and femur. A safety analysis was performed via dissection of the medial hind limb. The distance between neurovascular structures and arthroscopic portals was measured. Results: The acetabulum was more visible in the dorsal than in the medial approach, with mean visualization scores of 16 ± 0.00 and 11.83 ± 1.26, respectively. The medioventral side of the femur was significantly more visible in the medial than in the dorsal approach, with mean visualization scores of 3.9 ± 0.99 and 6.93 ± 0.58, respectively. Safety analysis confirmed the medial portal site was safe, provided that the surgeon has comprehensive knowledge of the joint. The minimum distance from the arthroscopic medial portals to the nearest neurovascular structures was 2.5 mm. Conclusions: A medial arthroscopic approach to the canine coxofemoral joint has potential clinical application. Dorsal and medial approaches differ significantly and have distinct purposes. The medial approach is useful to access the ventromedial joint, making it an eligible diagnostic method for an arthroscopic evaluation of this area.