• 한국신뢰성학회지:신뢰성응용연구
• /
• 제17권1호
• /
• pp.28-37
• /
• 2017

Purpose: This paper proposes a procedure that may infer and identify interaction failures in a module. Methods: In design FMEA, we defined an interaction model between components and proposed a method for selecting a single component by using the standard specification classification table and four methods for choosing the related components. We also introduced the function tree for function and requirement characteristic analysis and proposed utilization of standard stress lists and 1st and 2nd stress analysis tables to determine the effect the stress analysis has on interactions. Finally, the interaction mechanism diagram was proposed and used to infer the failure mechanism. Process FMEA also established procedures in a similar way. Results: We established a procedure for predicting the failure mode due to interaction between components based on Company A's multi-step FMEA procedure. Conclusion: By applying the proposed interaction FMEA procedure to the development model, we were able to confirm the effect of the new derivation on the failure mode of interaction, which was not predicted by the existing FMEA.

• Wind and Structures
• /
• 제20권2호
• /
• pp.143-168
• /
• 2015

A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.

• 한국철도학회논문집
• /
• 제18권4호
• /
• pp.363-373
• /
• 2015

본 논문은 휠-레일 사이의 접촉메카니즘을 이용하여 휠과 레일 사이의 분리를 허용하고, 횡 방향으로의 플랜지 접촉을 허용하는 비선형 동적 상호작용 해석법을 제시하는데 그 목적이 있다. 먼저 휠-레일 사이의 상호작용력을 압축스프링으로 이상화한 스프링 모델과 휠-레일 사이가 항상 접촉하고 있다는 가정하에 적용되는 non-jump모델에 대해 간략히 소개한 후 접촉메카니즘을 이용한 비선형 접촉모델에 대해 기술한다. 위 3가지 모델에 대한 수치해석 결과를 비교하기 위하여, 단순보 위를 지나가는 KTX열차에 대해 휠-레일 사이의 상호작용력을 각각 적용하여 동적 응답을 비교 분석하였다. 또한 특정 조건하에 플랜지 접촉을 강제 발생시켜 횡방향 응답의 변화를 살펴보았다.

• Geomechanics and Engineering
• /
• 제32권1호
• /
• pp.69-84
• /
• 2023

This paper proposes a novel frame element on Winkler-Pasternak foundation for analysis of a non-ductile reinforced concrete (RC) member resting on foundation. These structural members represent flexural-shear critical members, which are commonly found in existing buildings designed and constructed with the old seismic design standards (inadequately detailed transverse reinforcement). As a result, these structures always experience shear failure or flexure-shear failure under seismic loading. To predict the characteristics of these non-ductile structures, efficient numerical models are required. Therefore, the novel frame element on Winkler-Pasternak foundation with inclusion of the shear-flexure interaction effect is developed in this study. The proposed model is derived within the framework of a displacement-based formulation and fiber section model under Timoshenko beam theory. Uniaxial nonlinear material constitutive models are employed to represent the characteristics of non-ductile RC frame and the underlying foundation. The shear-flexure interaction effect is expressed within the shear constitutive model based on the UCSD shear-strength model as demonstrated in this paper. From several features of the presented model, the proposed model is simple but able to capture several salient characteristics of the non-ductile RC frame resting on foundation, such as failure behavior, soil-structure interaction, and shear-flexure interaction. This confirms through two numerical simulations.

• 유통과학연구
• /
• 제7권3호
• /
• pp.25-48
• /
• 2009

본 연구의 목적은 기술수용모델이 원격교육환경에서 인지된 상호(相互)작용에 미치는 영향을 탐색하고, 확장된 기술수용모델이 원격교육환경에서의 고객만족에 미치는 영향을 총체적으로 탐색하고자 하였다. 자료는 2009년 봄 학기에 원격교육대학에 등록된 842명의 학생들로부터 수집하였다. 또한 수집된 자료는 요인분석과 구조방정식 모형을 이용하여 분석하였다. 자료 분석 결과, 인지된 유용(有用)성이 원격교육환경에서의 인지된 상호(相互)작용과 유의한 관계를 가지고 있으며, 인지된 용이(容易)성, 유용(有用)성, 그리고 인지된 상호(相互)작용이 모두 고객만족에 유의한 영향을 미치는 것으로 나타났다.

• Wind and Structures
• /
• 제22권3호
• /
• pp.349-368
• /
• 2016

A preconditioning technique is presented for a simultaneous solution to wind-membrane interaction. In the simultaneous equations, a linear elastic model was employed to deal with the fluid-structure data transfer at the interface. A Lagrange multiplier was introduced to impose the specified boundary conditions at the interface and strongly coupled simultaneous equations are derived after space and time discretization. An initial linear elastic model preconditioner and modified one were derived by treating the linearized elastic model equation as a saddle point problem, respectively. Accordingly, initial and modified fluid-structure interaction (FSI) preconditioner for the simultaneous equations were derived based on the initial and modified linear elastic model preconditioners, respectively. Wind-membrane interaction analysis by the proposed preconditioners, for two and three dimensional membranous structures respectively, was performed. Comparison was made between the performance of initial and modified preconditioners by comparing parameters such as iteration numbers, relative residuals and convergence in FSI computation. The results show that the proposed preconditioning technique greatly improves calculation accuracy and efficiency. The priority of the modified FSI preconditioner is verified. The proposed preconditioning technique provides an efficient solution procedure and paves the way for practical application of simultaneous solution for wind-structure interaction computation.

• 한국멀티미디어학회논문지
• /
• 제1권2호
• /
• pp.215-223
• /
• 1998

본 논문에서는 월드와이드웹에 기반하면서 사용자간 상호작용을 극대화할 수 있는 통합 가상교육시스템인 WebClass를 설계하고 구현한 방법을 소개한다. 기존 가상교육 시스댐은 사용자간 상호작용 모텔을 제시하지 않고 다양한 상호작용 기능을 포함함으로써 각 기능들이 유연하게 통합되지 못했다 WebClass에서는 다양한 교수 모델을 지원하기 위한 상호작용 모텔을 설정하고 그 모텔에 기반하여 사용자와 가상교육시스템간의 상호작용을 지원하는 사용자 인터페이스를 설계하고 구현하였다. 따라서 단순한 기능위주의 통합이 아닌 사용자간의 상호작용을 기본으로 하여 다양한 상호작용 기능을 갖는 통합 가상교육시스템을 개발하였기 때문에 가상교육이 갖는 상호작용의 부족을 최대한 보완하였다. WebClass에서는 사용자간의 상호작용을 위해 비동기 공유 기능과 동기 공유 기능올 모두 지원한다 이들 공유 기능들은 유기적으로 결합하고 유연한 사용자 인터페이스를 사용하여 서로 통합함으로써 사용자간의 상호작용을 극대화하여 효율적인 가상교육을 지원할 수 있게 하였다.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 학술대회
• /
• pp.215-220
• /
• 2008

A numerical method for gas-liquid two-phase flow is applied to solve shock-bubble interaction problems. The present method employs a finite-difference Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL-TVD scheme. A homogeneous equilibrium cavitation model is used. By this method, a Riemann problem for shock tube was computed for validation. Then, shock-bubble interaction problems between cylindrical bubbles located in the liquid and incident liquid shock wave are computed.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년 추계학술대회논문집
• /
• pp.215-220
• /
• 2008

A numerical method for gas-liquid two-phase flow is applied to solve shock-bubble interaction problems. The present method employs a finite-difference Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL-TVD scheme. A homogeneous equilibrium cavitation model is used. By this method, a Riemann problem for shock tube was computed for validation. Then, shock-bubble interaction problems between cylindrical bubbles located in the liquid and incident liquid shock wave are computed.

• Journal of Information Technology Applications and Management
• /
• 제13권4호
• /
• pp.197-214
• /
• 2006

This study explores factors to facilitate web-based collaborative learning and the effect of learning, based on the PBL(Problem Based Learning) from the constructivist approach in e-learning. A research model, using the key variables such as situations, interactions, and systems, was developed. In order to test this proposed model, experimental design and post-survey was conducted to the learners who took on-line and off-line course with team project. In the research model, situation category was divided into instructor's support, unstructured problem, and self-directed learning. Interaction category was divided into three factors; 'interaction between learners', 'interaction between learner and instructor', and 'interaction between learner and technology'. System category was divided into.monitoring and incentives. As a result, it was found that collaborative learning can be improved by situations, interactions, and systems, and the effectiveness of learning can be improved by situations and interactions in PBL.