• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.883-886
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• 1998

In order to detect the user's gaze position on a monitor by computer vision, the accurate estimations of 3D positions and 3D motion of facial features are required. In this paper, we apply a EKF(Extended Kalman Filter) to estimate 3D motion estimates and assumes that its motion is "smooth" in the sense of being represented as constant velocity translational and rotational model. Rotational motion is defined about the orgin of an face-centered coordinate system, while translational motion is defined about that of a camera centered coordinate system. For the experiments, we use the 3D facial motion data generated by computer simulation. Experiment results show that the simulation data andthe estimation results of EKF are similar.e similar.

• 농업과학연구
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• 제48권4호
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• pp.1027-1037
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• 2021

This study aims to evaluate the performance of an electric multi-purpose cultivator through a simulation analysis. The simulation model was developed using commercial software, Simulation X, by applying the specifications of certain parts, such as an electric motor, a battery, and so on. The input parameter of the simulation was the engine load data according to the rotary tillage level using a conventional multi-purpose cultivator. The data were collected by configuring a load measurement system, and the load cycle was developed by repeating the data collection process under the most severe conditions. The average output engine torque values of conventional multi-purpose cultivator were 10.7, 13.0, 9.4, and 11.2 Nm in the D1P1, D1P2, D2P1, and D2P2 conditions, respectively. As a result of the simulation, the maximum values of the motor torque, rotational speed, and power of the electric multi-purpose cultivator were 16.8 Nm, 2,033.3 rpm, and 3.3 kW, respectively, and the motor was driven in sections within 70, 68, and 45% of the maximum output range. The rate of decrease of the battery state of charge (SOC) level per minute was approximately 0.6%, and it was possible to supply electric power to the motor for 9,550 sec. In the future study, research to verify and improve simulation models of electric multi-purpose cultivators should be conducted.

• Design & Manufacturing
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• 제11권1호
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• pp.30-33
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• 2017

In this study, the mold technology for manufacturing of porous implant was investigated. Firstly, we considered the concept of insert molding technology with 3D printing of porous inert part. The part on implant was designed in the end region of the implant. And then main implant bodies were manufactured using conventional machining method. The other porous parts were designed and optimized with molding simulation. As the feature size of porous implant was so small that perfect feature of it using 3D printing technology could not be obtained. So, we proposed another scheme for manufacturing of the porous implant in the replace of the former approach. Polymer mold cores with 3D printing technology were considered. The effects of addictive manufacturing process parameters on the properties of mechanical and dimensional accuracy were investigated. Direct 3D printed polymer mold cores were designed and manufactured under the simulation of thermal and molding analysis. It was shown that 3D printed mold core with polymer could be adapted to the injection molding for porous implant.

• 한국전산구조공학회논문집
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• 제30권3호
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• pp.223-230
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• 2017

토목시설물 건설사업에 BIM(building information modeling)이 적극적으로 도입되면서 시설물의 생애주기 동안의 활용도를 극대화할 수 있는 방안이 모색되고 있으며, 그 중, 시설물 공사 중 건설장비의 동적 거동을 반영한 검토 사례는 드물고 관련 기술 수준도 낮은 상황이다. 본 연구에서는 BIM 기반으로 구성된 가상현장 내에서 동적인 가상건설 장비 모델을 이용하여 공사단계에서 발생하는 장비운용의 안전성과 효율성을 검토할 수 있는 시뮬레이션 시스템을 개발하고 이를 실제 토목 현장에 적용하여 그 효용성을 분석하였다. 개발된 시뮬레이션 시스템이 건설장비에 대한 효과적인 3D 라이브러리 구축을 통해 공사관리자가 최적의 장비를 선정하고 경제적인 공사를 실현하기 위한 계획수립을 지원할 뿐 아니라 안전한 공사가 수행되도록 다각도의 분석을 가능케 해준다는 것을 확인할 수 있었다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.967-970
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• 2007

건설 프로젝트가 대형화 ${\cdot}$ 복잡화됨에 따라 그 관리 또한 방대한 정보량으로 인해 복잡성이 증대되어 가고 있따. 또한, IT기술이 발점함에 따라 건설기술의 선진화와 정보화를 목적으로 건설 프로젝트에 IT기술을 적극적으로 도입하고 있는 추세이다. 건설 프로젝트에서 IT기술을 도입함으로서 전문가의 개인적인 경험과 지식을 위주로 하는 공사 관리를 탈피하여 건설 프로젝트의 정보 공유 및 수집 ${\cdot}$ 축적을 효과적으로 관리 할 수 있게 되었고, 건설 프로젝트 참여 주체들간의 정보 공유 및 프로젝트 진행상황 파악이 원활하게 이루어지고 있다. 본 연구에서는 현재의 건설 산업의 정보화 구조와 정보 시스템인 PMIS 또는 유사기능 솔류선의 의의, 필요성 등을 소개하고, 현장에서 PMIS와 3D Simulation 시스템을 적용하여 정보시스템구축시의 기대효과를 분석하고자 한다.

• 한국기계가공학회지
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• 제17권6호
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• pp.68-74
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• 2018

Study on the Ti-6Al-4V have been carried out using cutting simulation, and researches for cutting force and chip shape prediction have been actively conducted under various conditions. However, a 3D printer application method using Ti-6Al-4V metal powder material as a high-power method has been studied for the purpose of prototyping, mold modification and product modification while lowering material removal rate. However, in the case of products / parts made of 3D printers using powder materials, problems may occur in the contact surface during tolerance management and assembly due to the degradation of the surface quality. As a result, even if a 3D printer is applied, post-processing through cutting is essential for surface quality improvement and tolerance management. In the cutting simulation, the cutting force and the chip shape were predicted based on the Johnson-Cook composition equation, but the shape of the shear type chip was not predictable. To solve this problem, we added a damaging term or strain softening term to the Johnson-Cook constitutive equation to predict chip shape. In this thesis, we applied the constant value of the S-K equations to the cutting simulation to predict the cutting force and compare with the experimental data to verify the validity of the cutting simulation and analyzed the machining characterization by considering conditions.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.376-386
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• 2020

The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value description, path element, and reverse motion. This method enables analysis without the need to integrate the stiffness matrix of the structure, because only motion equations of particles established according to Newton's second law are required. These characteristics of the VFIFE facilitate the modeling and computation efficiencies in analyzing the nonlinear dynamic problem of flexible pipe with large deflections. In this study, a three-dimensional (3-D) dynamical model based on 3-D beam element was established according to the VFIFE method. The deep-sea flexible pipe was described by a set of spatial mass particles linked by 3-D beam element. The motion and configuration of the pipe are determined by these spatial particles. Based on this model, a simulation procedure to predict the 3-D dynamical behavior of flexible pipe was developed and verified. It was found that the spatial configuration and static internal force of the mining pipe can be obtained by calculating the stationary state of pipe motion. Using this simulation procedure, an analysis was conducted on the static and dynamic behaviors of the flexible mining pipe based on a 1000-m sea trial system. The results of the analysis proved that the VFIFE method can be efficiently applied to the static and dynamic analyses of marine pipes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.421-424
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• 1998

In this paper are presented a newly proposed 3D monte carlo (MC) damage model for the dynamic simulation in order to more accurately and consistently predict the implant-induced point defect distributions of the various ions in crystalline silicon. This model was applied to phosphorus implants for the ULSI CMOS technology developement. In additon, a newly applied 3D-trajectory split method has been implemented into our model to reduce the statistical fluctuations of the implanted impurity and the defect profiles in the relatively large implanted area as compared to 1D or 2D simulations. Also, an empirical electronic energy loss model is proposed for phosphorus and silicon implants. The 3D formations of the amorphous region and the ultra-shallow junction around the implanted region could be predicted by using our model, TRICSI(Transport ions into crystal-silicon).

• 한국주거학회논문집
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• 제25권1호
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• pp.23-32
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• 2014

This research progressed space evaluation test with 3D simulation for exterior space of detached housing area among the Seoul spaces of child sex offense in 2010. Based on changing analysis on natural surveillance by spatial changes of each physical element, the purpose is to suggest effective construction planning measure for preventing child sex offense. The results of research are as follows. First, natural surveillance of space's height differences and width differences were compared and analyzed. As the result, footpath shows that stairs of slope didn't make lots of effects on visual block, not block of spatial moving, because of the difference of stair height. Also, in case of parking space, visual connection with footpath is expanded when designing pilotis rather than heightening floor height, so activities of exterior people could be seen more easily. Therefore, natural surveillance was higher. Second, natural surveillance of architectural elements by changes of footpath' width was compared and analyzed. As the result, openness of footpath should be secured rather than openness of architectural element. And, planning autonomy of architectural form could be more expanded when securing openness of footpath.

• 한국CDE학회논문집
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• 제21권2호
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• pp.159-169
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• 2016

In order to realize the virtual prototyping (VP) of digital products, it is important to provide the people involved in product development with the appropriate visualization and interaction of the products, and the vivid simulation of user interface (UI) behaviors in an interactive 3D virtual environment. In this paper, we propose an approach to web-based 3D virtual experience using Unity and Leap Motion. We adopt Unity as an implementation platform which easily and rapidly implements the visualization of the products and the design and simulation of their UI behaviors, and allows remote users to get an easy access to the virtual environment. Additionally, we combine Leap Motion with Unity to embody natural and immersive interaction using the user's hand gesture. Based on the proposed approach, we have developed a testbed system for web-based 3D virtual experience and applied it for the design evaluation of various digital products. Button selection test was done to investigate the quality of the interaction using Leap Motion, and a preliminary user study was also performed to show the usefulness of the proposed approach.