• 한국실내디자인학회논문집
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• 제37호
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• pp.119-128
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• 2003

The goal of this study was to understand human behavior in reference to wayfinding during emergency situations. In an emergency situation, it is recommended that evacuees follow instructions about an available exit rather than finding their way on their own. Wayfinding studies suggest that landmarks affect entire route communication. Landmark analysis for this study Identified describability, e.g., name and simplicity of landmark features. A virtual reality (VR) simulation test was conducted to examine the effect of landmarks on wayfinding. The independent variables were landmarks, smoke. Results suggest that the describability of landmarks is a positive Influence to route communication. Findings from this study, however, Indicates that smoke condition did not significantly affect participants' wayfinding.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.698-699
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• 2016

본 논문에서는 열차 정비 사고를 예방하기 위한 정비교육 시뮬레이션 시스템을 설계하고자 한다. 현재 운용되고 있는 철도관련 시뮬레이터 현황에 대해 분석하고 학습효과를 높이기 위해 열차 장치에 대한 기본 개념과 장치 정비 절차를 직접 학습할 수 있는 두 가지의 파트로 구성되며 두 번째 파트에는 교육공학 이론을 적용하여 VIEW모드와 TEST모드로 나누어 공부와 평가를 통해 학습할 수 있도록 설계하였다. 정비 교육 시뮬레이션이 운용된다면 안전한 상황에서 실무경험 능력 향상에 도움이 되는 학습을 할 수 있으며 정비교육에 대한 운영비용도 절감되는 효과를 기대할 수 있다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.67-68
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• 2009

Increasing use of embedded systems has made many improvements on hardware development for specific purpose. Hardware changes are more expensive and harder to implement rather than software changes. Developers need tools to do design and testing of new hardware. Many simulation tools have been made to mimic the hardware and allow developer to test programs on top of new hardware. Virtual Development Environment for Embedded Software (VDEES) is one of the alternatives available. It provides an open source based platform and an Integrated Development Environment (IDE) that can be used to build and testing newly made component, faster and at low-cost.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.425-428
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• 2001

In this paper, FMCW radar signal processing technique for the vehicle detection system are studied. And FMCW radar sensor is used as a equipment for vehicle detection. To test the performance of developed algorithm, the evaluation of the algorithm is done by simulation for signal processing technique of vehicle detection system. RADAR signal of a driving vehicle is generated by using the Matlab. Distance and velocity of vehicles are calculated with developed a1gorithm. Also the signal processing procedure is done for the virtual data with FM-AM converted noise.

• 한국압력기기공학회 논문집
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• 제19권2호
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• pp.117-129
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• 2023

Hydrogen embrittlement of a pipe is an important factor in hydrogen transport. To characterize hydrogen embrittlement, tensile and fracture toughness tests should be conducted. However, in the case of hydrogen-embrittled materials, it is difficult to perform tests in hydrogen environment, particularly at low temperatures. It would be useful to develop a methodology to predict the fracture toughness of hydrogen-embrittled materials at low temperatures using more efficient tests. In this study, the fracture toughness of API X52 steels in hydrogen at low temperatures is predicted from numerical simulation using coupled finite element (FE) damage analyses with FE diffusion analysis, calibrated by analyzing small punch test data.

• 한국시뮬레이션학회논문지
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• 제18권3호
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• pp.1-11
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• 2009

본 논문에서는 자동차 패널 자동창고 시스템의 PLC 시뮬레이션 적용 연구 사항에 관해 소개한다. 자동차 차종의 증가에 따라 차종 별 패널 공급의 복잡도가 향상되었다. 이를 해결하기 위해 AS/RS 시스템을 사용하지만, 내부 시스템 로직의 복잡성으로 인해 사전에 검증하는 것이 매우 어렵다. 특히 AS/RS시스템 제어의 중추적 역할을 하는 PLC는 하위 레벨의 언어로 기술되기 때문에, 사용자가 정확히 이해하고 검증을 수행하기 힘든 것이 현실이다. 본 논문에서는 이 같은 논리적 복잡성과 언어적 한계를 극복하고자 PLC 와 3D 모델을 연동하는 시뮬레이션 환경을 제안하였다. 특히 차체 조립라인의 설비 및 패널 데이터를 실측치를 기반으로 하였고, 실제 PLC 신호를 이용하여 환경을 구축함으로써 시스템 구축 이전에 시운전 환경을 완벽히 구현하였다. 사용자는 제안된 시뮬레이션 환경에서 AS/RS 로직을 시운전 할 수 있게 되었고, 이를 통해 경제적, 시간적 이득을 얻게 되는 장점을 갖는다.

• Journal of Power Electronics
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• 제18권4호
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• pp.1111-1126
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• 2018

In modern power systems, distributed generators (DGs) result in high stress on system frequency stability. Apart from the intermittent nature of DGs, most DGs do not contribute inertia or damping to systems. As a result, a new control method referred to as a virtual synchronous machine (VSM) has been proposed, which brought new characteristics to inverters such as synchronous machines (SM). DGs employing an energy storage system (ESS) provide inertia and damping through VSM control. Meanwhile, energy storage presents some physical constraints in the VSM implementation level. In this paper, a VSM mathematical model is built and analyzed. The dynamic responses of the output active power are presented when a step change in the frequency occurs. The influences of the inertia constant, damping factor and operating point on the ESS volume margins are investigated. In addition, physical constraints are proposed based on these analyses. The proposed physical constraints are simulated using PSCAD/EMTDC software and tested through RTDS experiment. Both simulation and RTDS test results verify the analysis.

• Wind and Structures
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• 제28권5호
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• pp.271-284
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• 2019

This paper describes the application of a novel virtual prototyping methodology to wind turbine blade design. Numeric modelling data and experimental data about turbine blade geometry and structural/dynamical behaviour are combined to obtain an affordable digital twin model useful in reducing the undesirable uncertainties during the entire turbine lifecycle. Moreover, this model can be used to track and predict blade structural changes, due for example to structural damage, and to assess its remaining life. A new interactive and recursive process is proposed. It includes CAD geometry generation and finite element analyses, combined with experimental data gathered from the structural testing of a new generation wind turbine blade. The goal of the research is to show how the unique features of a complex wind turbine blade are considered in the virtual model updating process, fully exploiting the computational capabilities available to the designer in modern engineering. A composite Sandia National Laboratories Blade System Design Study (BSDS) turbine blade is used to exemplify the proposed process. Static, modal and fatigue experimental testing are conducted at Clarkson University Blade Test Facility. A digital model was created and updated to conform to all the information available from experimental testing. When an updated virtual digital model is available the performance of the blade during operation can be assessed with higher confidence.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2159-2167
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• 2006

In order to find out a physical quantity which controls the fatigue life of a structure and to predict the fatigue life of tires, a finite element simulation methodology to use the cracking energy density (CED) and the virtual crack closure technique (VCCT) was proposed and applied to three different tires of a similar size. CED was calculated to predict the location of a crack initiation, and VCCT was used to obtain the strain energy release rate (SERR) at the tip of an initiated crack. Finite element simulations showed that SERR oscillated in the circumferential direction with its minimum occurring just before the contact zone and its maximum occurring just after the center of the contact zone, and SERR was affected significantly by the frictional force acting on the crack surface. In addition, a durability test was conducted to measure the fatigue life of the three tires. The comparison of SERR values with the test data revealed that the fatigue life increased as the amplitude of SERR decreased or as the R-ratio of SERR increased.

• Journal of Welding and Joining
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• 제33권3호
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• pp.40-46
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• 2015

Welding is one of the most fundamental and necessary work in the industry that demand sophistication of skilled workers. This study is to introduce welding simulator as a training tool, to verify its effectiveness and to measure satisfaction of the trainees. A group of freshman students at a Korea Polytechnics College in their twenties with less experience of welding participated in the study. They were divided into two groups and took a traditional training course (comparison group) and a training course with welding simulator applied reality/haptic technology (experimental group) for same hours respectively. To evaluate training effect, a national certificate test and a survey based on Phillips' ROI (Return on Investment) methodology were conducted by the students and the college respectively. And satisfaction survey among the students based on Kirkpatrick's Four-Level Evaluation Model was also carried out. The results showed that all students in the experimental group passed the national certificate test and the ROI of the experimental group for five years were 110% higher than the comparison group. Furthermore, 25% more students in the experimental group replied "very satisfied" about the overall training course and 75% more students in the same group found that the simulation was very similar to the real welding.