• Transactions of Materials Processing
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• v.32 no.6
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• pp.360-366
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• 2023

This study is concerned with the surface quality of products according to the material and coating condition of the forming tool in incremental sheet forming. Three forming tools, SKD11 with and without diamond-like-coating (DLC) and polymer tool tip, were used to form conical and pyramidal geometries to take into account the influence of friction between the forming tool and the sheet on the surface quality including geometric accuracy of deformed samples. Each test was performed using SUS304 with a thickness of 0.4 mm according to different incremental depths per lap of 0.5 mm, 1.0 mm, and 1.5 mm for the contour tool path, considering the increase in normal force which is associated with the frictional behavior during local deformation. The surface quality was then investigated through surface roughness measured with KEYENCE VR-6000 and relative strain distribution including deformed shape analyzed with ARGUS which is a non-contact optical strain measurement system. Differences between 3D CAD surfaces and captured geometry from experiments were evaluated to compare the effect of friction on geometric accuracy. From comparisons of experimental results, it was revealed that the polymer-based tool tip can improve surface quality and geometric accuracy by reducing the undesired material flow due to local friction in the increment sheet forming process.

• Journal of Broadcast Engineering
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• v.25 no.2
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• pp.185-191
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• 2020

MPEG-I is actively working on standardization on the immersive video coding which provides up to 6 degree of freedom (6DoF) in terms of viewpoint. In a virtual space of 3DoF+, which is defined as an extension of 360 with motion parallax, looking at the scene from another viewpoint (another position in space) requires rendering an additional viewpoint using multiple videos included in the 3DoF+ video. In the MPEG-I Visual workgroup, efficient coding methods for 3DoF+ video are being studied, and they released Test Model for Immersive Video (TMIV) recently. This paper presents a patch packing method which packs the patches into atlases efficiently for improving coding efficiency of 3DoF+ video in TMIV. The proposed method improves the reconstructed view quality with reduced coding artifacts by introducing guardbands between patches in the atlas.

• Broadcasting and Media Magazine
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• v.23 no.1
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• pp.33-45
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• 2018

최근 차세대 미디어 중 하나로 가상의 환경 내에서 극대화된 현실감 및 몰입감을 사용자에게 제공해 줄 수 있는 몰입형 미디어(Immersive Media)가 각광받고 있다. 이를 반영하듯 360도 전방위 영상을 이용한 VR미디어에 사용자의 움직임에 따라 자연스러운 사실감 및 입체감을 제공하는 Light Field 미디어 기술을 접목하려는 시도가 가속화되고 있으며, MPEG에서도 6DoF(Degrees of Freedom)기반의 LF 미디어를 서비스하기 위한 MPEG-I(Immersive) 표준화가 진행 중에 있다. 본 고에서는 LF 미디어 특성 및 이를 획득하고 재생하기 위한 요소기술 개발 현황을 살펴보고, LF 기술이 적용된 MPEG 표준화 동향을 소개한다.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.47-55
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• 2019

In past patriarchal societies, childbearing was considered the sole possession of women. At a time when women were struggling to move into society, the concept of parenting as the mainstay of the capitalist economic society and the head of the family has naturally been taken for granted by a woman named "housewife." Since the role of male babies is as important as that of females, Fathers are trying to promote the importance of the effects of fathers due to active participation in childcare and help change old perceptions of the past. Men also know the importance of participating in childcare in early childhood, but often do not know what their children want or why they cry due to lack of basic child care knowledge and lack of education. We tried to give fathers the meaning of indirect experience and change their perception of parenting by producing interactive VR content, which is completed with dad's participation, so that they can experience the child in person. In addition, through familiar childcare professional product advertisement and 360 degree stereo sound. It is made to immerse in the game to gain persuasive effect, inducing fathers to have interest and interest in childrearing.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.298-301
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• 2019

이미지 스티칭은 다수의 이미지를 합성하여 카메라의 좁은 시야각(Field of View) 문제를 해결하는 기술이다. 최근 동영상 기반 Panorama, Super Resolution, 360 VR (Virtual Reality) 등의 컨텐츠 사용이 증가함에 따라, 보다 빠르고 정확한 이미지 스티칭 기술의 필요성이 커지고 있다. 지금까지 필요 성능을 만족시키기 위해 많은 알고리즘이 제안되고 있지만, 정확성을 측정하는 객관적 평가 방법은 표준화되지 않고 있다. 최근에서야 PSNR (Peak Signal-to-Noise Ratio) 과 SSIM (Structural Similarity index method) 측정값을 제시하는 방법이 주를 이루고 있지만, 본 논문에서는 PSNR 과 SSIM 측정 방식의 문제점을 밝히고 지역 차분 픽셀 평가 방법을 제안한다. 기하적 유사성과 광도 측정 정보를 포괄하는 LDPM(Local Differential Pixel Mean) 평가 방식을 테스트 이미지를 통해 증명하고 SSIM 과 비교를 통해 해당 평가 방법의 이점을 밝힌다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.59-61
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• 2021

뷰포트 예측은 360° VR(Virtual Reality) 영상 전송에서 사용자의 안정적인 콘텐츠 몰입을 위해 고안된 기법이다. 하지만 뷰포트 예측 모델의 정확도는 예측에 활용되는 데이터 또는 네트워크 상황에 따라 변동될 수 있다. 특히 사용자의 움직임은 뷰포트 예측 성능에 직접적인 영향을 주기 때문에 사용자의 움직임에 대한 정밀한 분석이 중요하다. 본 논문에서는 뷰포트 적응적 전송의 효율적인 개선을 위하여 HMD(Head-Mounted Display)의 속도가 뷰포트 예측에 미치는 영향을 분석한다.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.40.2-40.2
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• 2021

최근 COVID-19의 확산에 따라 비대면 학습의 중요성이 화두로 오르고 있다. 과학관과 같은 다중이용시설을 이용하는 방법에서 각 학교, 또는 가정에서 지도할 수 있는 교육 방법의 변화 또한 논의해야 할 때이다. 특히 천문학 교육의 장으로 활용되고 있는 천체투영관(Planetarium)은 다중이용시설로, 상황에 따라 여러 가지 제약을 가지므로 시·공간 제약을 받지 않는 교육프로그램의 개발이 필요하고 볼 수 있다. 본 연구에서는 천체시뮬레이션 소프트웨어를 활용한 스크립트 제작 및 360° VR 영상 제작기술을 개발하고 온라인 플랫폼을 활용하여 천체투영관을 방문하지 않은 비대면 환경에서 도 참가자개인의 휴대기기등을 통한 몰입도 높은 천문학 교육을 구현할 수 있는 프로그램을 개발하여 새로운 환경에 대한 적용 기회를 제공하고자 한다. 나아가 개발한 프로그램을 천체투영관에 적용하여 천체투영관 활용 천문학 교육프로그램과 교육과정과 연계한 교육콘텐츠 개발에 활용되기를 기대한다.

• Journal of Sensor Science and Technology
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• v.12 no.2
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• pp.72-78
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• 2003

To observe the effect of excitation coil pitch on the micro fluxgate magnetic sensor, two sensors are fabricated using multi layer board process and the pitch distance of excitation coil are $260\;{\mu}m$ and $520\;{\mu}m$, respectively. The fluxgate sensor consists of five PCB stack layers including one layer of magnetic core and four layers of excitation and pick-up coils. The center layer as magnetic core is made of a Co-based amorphous magnetic ribbon with extremely high DC permeability of ${\sim}100,000$ and has a rectangular-ring shape to minimize the magnetic flux leakage. Four outer layers as excitation and pick-up coils have a planar solenoid structure and are made of copper foil. In case of the fluxgate sensor having the excitation coil pitch of $260\;{\mu}m$, excellent linear response over the range of $-100\;{\mu}T$ to $+100\;{\mu}T$ is obtained with sensitivity of 780 V/T at excitation sine wave of $3V_{p_p}$ and 360 kHz. The chip size of the fabricated sensing element is $7.3\;{\times}\;5.7\;mm^2$. The very low power consumption of ${\sim}8\;mW$ is measured. This magnetic sensor is very useful for various applications such as: portable navigation systems, telematics, VR game and so on.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.19-23
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• 2002

This paper presents a micro fluxgate magnetic sensor in printed circuit board (PCB). In order to observe the effect of the closed magnetic path, the magnetic cores of rectangular-ring and two bars were each fabricated. Each fluxgate sensor consists of five PCB stack layers including one layer magnetic core and four layers of excitation and pick-up coils. The center layer as a magnetic core is made of a Co-based amorphous magnetic ribbon with extremely high DC permeability of ~100,000. Four outer layers as an excitation and pick-up coils have a planar solenoid and are made of copper foil. In case of the fluxgate sensor having the rectangular-ring shaped core, excellent linear response over the range of -100 $\mu$T to ＋ 100 $\mu$T is obtained with 540 V/Tsensitivity at excitation square wave of 3 $V_{p-p}$ and 360 KHz. The chip size of the fabricated sensing element is $7.3 \times 5.7\textrm{mm}^2$. The very low power consumption of ~8 mW was measured. This magnetic sensor is very useful for various applications such as: portable navigation systems, telematics, VR game and so on.n.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.375-380
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• 2022

Virtual and augmented reality technologies provide access to learning materials and improve the organization of a modern library's media space. This article aims to identify the significance and role of virtual and augmented reality technologies in the modern library's media space organization. Methodology. The research uses a university library case study methodology to empirically investigate virtual and augmented reality technologies. Results. Virtual and augmented reality technologies provide research and improve learning outcomes by engaging students and learners with significant interest in such technologies. Libraries offer users the opportunity to create their VR content through available software. Students can test their VR content in the libraries' labs. Libraries support access to a variety of virtual and augmented reality content. The content is accessed using "virtual reality headsets" for viewing and workstations with "authoring software and loanable 360 cameras" for creating. The library lab is a space to support students' digital creativity and research through virtual and augmented reality. There are 3D Design Labs within the libraries as a medium to large group design learning spaces with virtual reality technology. Libraries form a media space where users can create videos, podcasts, portfolios, edit media, and book tours, and students and researchers can explore different scientific knowledge. In this way, technology ensures that risks in learning are minimized as opposed to hands-on seminars and classes.