• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.55-58
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• 2008

Designers, who design industry products, use CAD(Computer Aided Design) tools for making new design and looking around virtual 3D models. Hand-drawings and sketches show only one viewpoint limiting 3D perception. However, CAD system that provides automation and multiple view points, can help to save time and cost. Accordingly, we developed Augmented Reality(AR) and Rapid Prototyping(RP) based product design system that is interactive and realistic This AR based design system utilize mockups that are made of urethane and styrofoam where as users change 3D model's color, texture and user interface. These interactive ways help to evaluate design more instinctively.

• Advances in aircraft and spacecraft science
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• v.4 no.3
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• pp.219-235
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• 2017

The large container ships and fast patrol boats are complex marine structures. Therefore, their global mechanical behaviour has long been modeled mostly by refined beam theories. Important issues of cross section warping and bending-torsion coupling have been addressed by introducing special functions in these theories with inherent assumptions and thus compromising their robustness. The 3D solid Finite Element (FE) models, on the other hand, are accurate enough but pose high computational cost. In this work, different marine vessel structures have been analysed using the well-known Carrera Unified Formulation (CUF). According to CUF, the governing equations (and consequently the finite element arrays) are written in terms of fundamental nuclei that do not depend on the problem characteristics and the approximation order. Thus, refined models can be developed in an automatic manner. In the present work, a particular class of 1D CUF models that was initially devised for the analysis of aircraft structures has been employed for the analysis of marine structures. This class, which was called Component-Wise (CW), allows one to model complex 3D features, such as inclined hull walls, floors and girders in the form of components. Realistic ship geometries were used to demonstrate the efficacy of the CUF approach. With the same level of accuracy achieved, 1D CUF beam elements require far less number of Degrees of Freedom (DoFs) compared to a 3D solid FE solution.

• Journal of Korean Neurosurgical Society
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• v.62 no.4
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• pp.398-404
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• 2019

Objective : Recently, three-dimensional (3D) printed models of the intracranial vascular have served as useful tools in simulation and training for cerebral aneurysm clipping surgery. Precise and realistic 3D printed aneurysm models may improve patients' understanding of the 3D cerebral aneurysm structure. Therefore, we created patient-specific 3D printed aneurysm models as an educational and clinical tool for patients undergoing aneurysm clipping surgery. Herein, we describe how these 3D models can be created and the effects of applying them for patient education purpose. Methods : Twenty patients with unruptured intracranial aneurysm were randomly divided into two groups. We explained and received informed consent from patients in whom 3D printed models-(group I) or computed tomography angiography-(group II) was used to explain aneurysm clipping surgery. The 3D printed intracranial aneurysm models were created based on time-of-flight magnetic resonance angiography using a 3D printer with acrylonitrile-butadiene-styrene resin as the model material. After describing the model to the patients, they completed a questionnaire about their understanding and satisfaction with aneurysm clipping surgery. Results : The 3D printed models were successfully made, and they precisely replicated the actual intracranial aneurysm structure of the corresponding patients. The use of the 3D model was associated with a higher understanding and satisfaction of preoperative patient education and consultation. On a 5-point Likert scale, the average level of understanding was scored as 4.7 (range, 3.0-5.0) in group I. In group II, the average response was 2.5 (range, 2.0-3.0). Conclusion : The 3D printed models were accurate and useful for understanding the intracranial aneurysm structure. In this study, 3D printed intracranial aneurysm models were proven to be helpful in preoperative patient consultation.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.19-28
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• 2017

There exist a variety of VR(Virtual Reality) contents that have been developed by the use of the latest VR technologies. Unlike the rapid advances in the recent VR devices however, the development of VR based game contents that fully utilize such cutting-edge devices has been lackluster. Using more accessible form of smartphone-based HMDs(Head-Mounted Displays), we compare two popular VR presentation methods(a realistic 3D VR karaoke room and a 360 degree video karaoke room) and analyze their users' immersion and realistic perception. We expect that our study can be utilized as a supporting guideline for future smartphone-based VR content developments.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.265-268
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• 2002

얼굴은 성별, 나이, 인종에 따라 다양한 특징을 가지고 있어서 개개인을 구별하기가 쉽고 내적인 상태를 쉽게 볼 수 있는 중요한 도구로 여겨지고 있다. 본 논문은 얼굴표정 애니메이션을 위한 효과적인 방법으로 실제얼굴의 피부조직 얼굴 근육 등 해부학적 구조에 기반한 근육기반모델링을 이용하는 방법을 소개하고자 한다. 제안하는 시스템의 구성은 얼굴 와이어프레임 구성과 폴리곤 메쉬분할 단계, 얼굴에 필요한 근육을 적용시키는 단계, 근육의 움직임에 따른 얼굴 표정생성단계로 이루어진다. 와이어프레임 구성과 폴리곤 메쉬 분할 단계에서는 얼굴모델을 Water[1]가 제안한 얼굴을 기반으로 하였고, 하나의 폴리곤 메쉬를 4등분으로 분할하여 부드러운 3D 얼굴모델을 보여준다. 다음 단계는 얼굴 표정생성에 필요한 근육을 30 개로 만들어 실제로 표정을 지을 때 많이 쓰는 부위에 적용시킨다. 그 다음으로 표정생성단계는 FACS 에서 제안한 Action Unit 을 조합하고 얼굴표정에 따라 필요한 근육의 강도를 조절하여 더 자연스럽고 실제감 있는 얼굴표정 애니메이션을 보여준다.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.385-391
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• 2021

3D modeling of the human body is an integral part of computer graphics. Among them, several studies have been conducted on hair modeling, but there are generally few studies that effectively implement hair and face modeling simultaneously. This study has the originality of providing users with customized face modeling and hair modeling that is different from previous studies. For realistic hair styling, We design and realize hair segmentation using FCN, and we select the most appropriate model through comparing PSPNet, DeepLab V3+, and MobileNet. In this study, we use the open dataset named Figaro1k. Through the analysis of iteration and epoch parameters, we reach the optimized values of them. In addition, we experiment external parameters about the location of the camera, the color of the lighting, and the presence or absence of accessories. And the environmental analysis factors of the avatar maker were set and solutions to problems derived during the analysis process were presented.

• The KIPS Transactions:PartB
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• v.14B no.4
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• pp.311-320
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• 2007

This paper presents vision-based 3D facial expression animation technique and system which provide the robust 3D head pose estimation and real-time facial expression control. Many researches of 3D face animation have been done for the facial expression control itself rather than focusing on 3D head motion tracking. However, the head motion tracking is one of critical issues to be solved for developing realistic facial animation. In this research, we developed an integrated animation system that includes 3D head motion tracking and facial expression control at the same time. The proposed system consists of three major phases: face detection, 3D head motion tracking, and facial expression control. For face detection, with the non-parametric HT skin color model and template matching, we can detect the facial region efficiently from video frame. For 3D head motion tracking, we exploit the cylindrical head model that is projected to the initial head motion template. Given an initial reference template of the face image and the corresponding head motion, the cylindrical head model is created and the foil head motion is traced based on the optical flow method. For the facial expression cloning we utilize the feature-based method, The major facial feature points are detected by the geometry of information of the face with template matching and traced by optical flow. Since the locations of varying feature points are composed of head motion and facial expression information, the animation parameters which describe the variation of the facial features are acquired from geometrically transformed frontal head pose image. Finally, the facial expression cloning is done by two fitting process. The control points of the 3D model are varied applying the animation parameters to the face model, and the non-feature points around the control points are changed by use of Radial Basis Function(RBF). From the experiment, we can prove that the developed vision-based animation system can create realistic facial animation with robust head pose estimation and facial variation from input video image.

• ETRI Journal
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• v.39 no.3
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• pp.417-427
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• 2017

This paper investigates the security of constant weight countermeasures, which aim to produce indistinguishable leakage from sensitive variables and intermediate variables, assuming a constant Hamming distance and/or Hamming weight leakages. To investigate the security of recent countermeasures, contrary to many related studies, we assume that the coefficients of the simulated leakage models follow a normal distribution so that we may construct a model with approximately realistic leakages. First, using our simulated leakage model, we demonstrate security holes in these previous countermeasures. Subsequently, in contrast to the hypotheses presented in previous studies, we confirm the resistance of these countermeasures to a standard correlation power analysis (CPA). However, these countermeasures can allow a bitwise CPA to leak a sensitive variable with only a few thousand traces.

• Atmosphere
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• v.32 no.3
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• pp.235-246
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• 2022

A large number of MJO skill metrics and process-oriented MJO simulation metrics have been developed by previous studies including the MJO Working Group and Task Force. To assess models' successes and shortcomings in the MJO simulation, a standardized set of diagnostics with the additional set of dynamics-oriented diagnostics are applied. The Global Coupled (GC) model developed for the operation of the climate prediction system is used with the comparison between the GC2 and GC3.1. Two GC models successfully capture three-dimensional dynamic and thermodynamic structure as well as coherent eastward propagation from the reference regions of the Indian Ocean and the western Pacific. The low-level moisture convergence (LLMC) ahead of the MJO deep convection, the low-level westerly and easterly associated with the coupled Rossby-Kelvin wave and the upper-level divergence are simulated successfully. The GC3.1 model simulates a better three-dimensional structure of MJO and thus reproduces more realistic eastward propagation. In GC2, the MJO convection following the LLMC near and east of the Maritime Continent is much weaker than observation and has an asymmetric distribution of both low and upper-level circulation anomalies. The common shortcomings of GC2 and GC3.1 are revealed in the shorter MJO periods and relatively weak LLMC as well as convective activity over the western Indian Ocean.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.72.1-72.1
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• 2014

In this study, we extrapolate a nonlinear force-free field (NLFFF) from an observed photospheric magnetic field to understand the three-dimensional (3D) coronal magnetic field producing a huge solar flare. The purpose of this study is to develop a NLFFF extrapolation code based on the so-called MHD relaxation method and check how accurately our model reconstructs a coronal field. Furthermore, we apply it to the photospheric magnetic field obtained by Helioseismic and Magnetic Imager (HMI) on board Solar Dynamics Observatory (SDO) to reconstruct a 3D magnetic structure. We first investigate factors in controlling the accuracy of our NLFFF code by using a semi-analytical solution obtained by Low & Lou (1990). To extend a work done by Inoue et al. (2014), we apply various boundary conditions at the side and top boundaries in order to make our solution close to a realistic solution. As a consequence, our solution has a good accuracy when three components of a reference field are all fixed at the boundaries. Furthermore, it is also found that our solution is well matched to the Low & Lou solution in the central area of a simulation domain when the three components of a potential field are fixed at side and top boundaries (this approach is close to a realistic solution). Finally, we present the 3D coronal magnetic field producing an X 1.5-class flare in the active region 11166 through the extrapolation from SDO/HMI.