• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.557-560
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• 2020

최근, 광소자에서 공간 변조되는 wavefront profile 특성을 광소자의 표면 단차 변화 없이 단일 두께 박막 상에서 자유로이 구현할 수 있는 기하위상 홀로그램 (geometric phase hologram) 기반의 optical component에 대한 관심이 증대되고 있다. 특히 이를 이용해 제작된 기하위상 렌즈 (geometric phase lens)는 dynamic phase의 공간적 차이에 의해 구현되던 기존 bulk optics 기반의 lens 대비 초박형으로 제작이 가능한 파장 선택적 flat optics 기술로써, 다초점 및 경량화를 요구하는 차세대 디스플레이 기술 (augmented reality 또는 AR, mixed reality 또는 MR) 및 광파변조 및 제어를 요구하는 홀로그래픽 카메라 분야에 대한 응용처로 많은 주목을 받고 있다. 이에 본 논문에서는 해당 기하 위상렌즈에 대한 원리 및 이에 따른 개발이슈 및 해결법에 대해 연구 하였으며, 이에 대한 응용처로 기하위상 렌즈의 편광에 따른 이중초점특성을 이용해, 기존 단일 초점 형성이 가능한 AR기기 대비, 다초점 형성이 가능한 switchable dual-depth 3D AR device를 compact한 모듈과 함께 구현하였다. 또한, 기하위상렌즈의 광파 변조 및 분리특성을 이용한 기하위상 렌즈기반의 자가간섭 홀로그래픽 시스템(GP-self-interference incoherent digital holographic, GP-SIDH)에 편광 이미지센서 적용과 함께 맞춤형 설계/제작된 기하 위상렌즈를 적용함으로써, 기존 GP-SIDH 시스템대비 안정적으로 실시간 복소 홀로그램 획득이 가능한 실시간 공간영상정보 획득용 GP-SIDH을 동영상 프레임으로 구현하였다.

• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.49-55
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• 2022

In this paper, we propose an obstacle detection method that can operate robustly even in external environmental factors such as weather. In particular, we propose an obstacle detection system that can accurately inform dangerous situations in AR through DB-based feature matching and RANSAC-based multiplane method. Since the approach to detecting obstacles based on images obtained by RGB cameras relies on images, the feature detection according to lighting is inaccurate, and it becomes difficult to detect obstacles because they are affected by lighting, natural light, or weather. In addition, it causes a large error in detecting obstacles on a number of planes generated due to complex terrain. To alleviate this problem, this paper efficiently and accurately detects obstacles regardless of lighting through DB-based feature matching. In addition, a criterion for classifying feature points is newly calculated by normalizing multiple planes to a single plane through RANSAC. As a result, the proposed method can efficiently detect obstacles regardless of lighting, natural light, and weather, and it is expected that it can be used to secure user safety because it can reliably detect surfaces in high and low or other terrains. In the proposed method, most of the experimental results on mobile devices reliably recognized indoor/outdoor obstacles.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.30-31
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• 2009

Early detection of schedule delay in field construction activities is vital to project management. It provides the opportunity to initiate remedial actions and increases the chance of controlling such overruns or minimizing their impacts. This entails project managers to design, implement, and maintain a systematic approach for progress monitoring to promptly identify, process and communicate discrepancies between actual and as-planned performances as early as possible. Despite importance, systematic implementation of progress monitoring is challenging: (1) Current progress monitoring is time-consuming as it needs extensive as-planned and as-built data collection; (2) The excessive amount of work required to be performed may cause human-errors and reduce the quality of manually collected data and since only an approximate visual inspection is usually performed, makes the collected data subjective; (3) Existing methods of progress monitoring are also non-systematic and may also create a time-lag between the time progress is reported and the time progress is actually accomplished; (4) Progress reports are visually complex, and do not reflect spatial aspects of construction; and (5) Current reporting methods increase the time required to describe and explain progress in coordination meetings and in turn could delay the decision making process. In summary, with current methods, it may be not be easy to understand the progress situation clearly and quickly. To overcome such inefficiencies, this research focuses on exploring application of unsorted daily progress photograph logs - available on any construction site - as well as IFC-based 4D models for progress monitoring. Our approach is based on computing, from the images themselves, the photographer's locations and orientations, along with a sparse 3D geometric representation of the as-built scene using daily progress photographs and superimposition of the reconstructed scene over the as-planned 4D model. Within such an environment, progress photographs are registered in the virtual as-planned environment, allowing a large unstructured collection of daily construction images to be interactively explored. In addition, sparse reconstructed scenes superimposed over 4D models allow site images to be geo-registered with the as-planned components and consequently, a location-based image processing technique to be implemented and progress data to be extracted automatically. The result of progress comparison study between as-planned and as-built performances can subsequently be visualized in the D4AR - 4D Augmented Reality - environment using a traffic light metaphor. In such an environment, project participants would be able to: 1) use the 4D as-planned model as a baseline for progress monitoring, compare it to daily construction photographs and study workspace logistics; 2) interactively and remotely explore registered construction photographs in a 3D environment; 3) analyze registered images and quantify as-built progress; 4) measure discrepancies between as-planned and as-built performances; and 5) visually represent progress discrepancies through superimposition of 4D as-planned models over progress photographs, make control decisions and effectively communicate those with project participants. We present our preliminary results on two ongoing construction projects and discuss implementation, perceived benefits and future potential enhancement of this new technology in construction, in all fronts of automatic data collection, processing and communication.

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.181-190
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• 2023

In this study, we compared discourse by environments for using tools in terms of participation types, discourse types, and knowledge building processes. 24 first-year high school students were divided into six groups. They were assigned to the sharing tools environment, which used one marker and one smart device, or the individual tools environment, which used markers and smart devices individually. Students participated in small group learning using AR application based on the concept of chemical bonding. All classes were video- and audio-taped. Semi-structured interviews were conducted with six students who voluntarily agreed. The results of the study revealed that the sharing tools environment had a high proportion of one-student dominating type, while the individual tools environment had a high proportion of partly participating type and most students participating type. In the individual tools environment, the ratio of knowledge sharing and knowledge construction discourse was similar compared to the tool sharing environment, and the sub-discourse types were also diverse. In the sharing tools environment, only some students had a meaningful knowledge building process. On the other hand, in the individual tools environment, most of the group members constructed knowledge about the target concept, and had a meaningful knowledge building process. In addition, the misconceptions that appeared to some group members were corrected through small group discussions.

• Journal of Computational Design and Engineering
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• v.1 no.3
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• pp.153-160
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• 2014

As smartphones came into wide use recently, it has become increasingly popular not only among young people, but among middle-aged people as well. Most smartphones adopt capacitive full touch screen, so touch commands are made by fingers unlike the PDAs in the past that use touch pens. In this case, a significant portion of the smartphone's screen is blocked by the finger so it is impossible to see the screens around the finger touching the screen; this causes difficulties in making precise inputs. To solve this problem, this research proposes a method of using simple AR markers to improve the interface of smartphones. A marker is placed in front of the smartphone camera. Then, the camera image of the marker is analyzed to determine the position of the marker as the position of the mouse cursor. This method can enable click, double-click, drag-and-drop used in PCs as well as touch, slide, long-touch-input in smartphones. Through this research, smartphone inputs can be made more precise and simple, and show the possibility of the application of a new concept of smartphone interface.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.470-472
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• 2016

최근 현실의 이미지나 배경에 3차원 가상 이미지를 겹쳐서 하나의 영상으로 보여주는 증강현실 기술들이 개발되고 있으며, 특히 애플리케이션에 따른 증강현실기반의 소프트웨어 들이 많이 개발되어 지고 있다. 하지만 대부분의 증강현실 기반의 애플리케이션은 GPS를 사용하여 사용자에게 서비스를 제공하는데, GPS값이 정확하지 않아 위치에 대한 신뢰도가 떨어지는 단점을 가지고 있다. 따라서 본 연구에서는 기존 GPS 기능과 지자기, 자이로, 가속도 센서를 통한 방향감지 인식을 포함하여 증강현실 기반의 애플리케이션을 개발하여 위치에 대한 신뢰도를 증가하고자 한다. 특히, 캠퍼스 가이드 서비스 애플리케이션을 개발하여 기존의 다른 애플리케이션의 문제점을 개선하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.362-364
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• 2011

1990년 증강현실이라는 용어가 처음 사용된 후 2000년대 중반까지는 연구개발 및 시험적용단계에 머물러 있었으나, 최근 카메라와 그래픽 처리 능력을 높인 단말기, 충분한 속도의 무선통신, GPS 등의 기능을 갖춘 스마트 폰이 등장하면서 실용화 단계에 진입을 하였다. 국내 네일 산업은 2008년 시장규모 4830억 원으로 매년 고속 성장을 하고 있으며 일본의 경우 2010년도에 약2015억 엔으로 2009년도의 약1971억 엔에 비교하여 2.2% 증가하였다. 이처럼 시장의 규모는 매년 커지고 다양해지면서 여러 번의 시행착오를 거쳐야 마음에 드는 네일 케어를 받을 수 있기 때문에 상당히 힘들고 번거롭다. 그래서 본 논문에서는 유비쿼터스 시대를 맞이하여 증강현실을 이용한 네일 샵 적용 방안을 연구하였다. 증강현실 기술을 이용하면 색을 칠하기 전 색이 자신의 손에 맞는지를 알아볼 수 있고 예상되는 결과를 알아 볼 수 있어서 다양해진 소비자들의 니즈를 충족시켜 줄 뿐만 아니라 네일 케어를 받기 전 시행착오를 겪는 소비자들에게 도움을 줄 것이다. 따라서 본 논문에서 제시한 증강현실을 이용한 네일 샵 적용은 국내뿐만 아니라 세계적으로 네일 산업분야에 큰 발전을 도래 할 수 있을 것으로 기대한다.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.45-53
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• 2012

This research aims at developing an electronic culture atlas using smart phones as a way to share the research results of Mind Humanities. An electronic atlas offers the web service of a great deal of information without the limitation of paper, which is different from the existing paper maps. When the concept of culture is added to an electronic atlas, it becomes an electronic culture atlas. To create an application program using smartphones, their various features should be understood and the development method to maximize them is necessary. Accordingly, in this paper, what needs to be taken into consideration for the service based on smartphones and the characteristics of smartphones to be considered in the development process were examined.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.383-403
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• 2021

With the development of mobile edge computing (MEC), some late-model application technologies, such as self-driving, augmented reality (AR) and traffic perception, emerge as the times require. Nevertheless, the high-latency and low-reliability of the traditional cloud computing solutions are difficult to meet the requirement of growing smart cars (SCs) with computing-intensive applications. Hence, this paper studies an efficient offloading decision and resource allocation scheme in collaborative vehicular edge computing networks with multiple SCs and multiple MEC servers to reduce latency. To solve this problem with effect, we propose a context-aware offloading strategy based on differential evolution algorithm (DE) by considering vehicle mobility, roadside units (RSUs) coverage, vehicle priority. On this basis, an autoregressive integrated moving average (ARIMA) model is employed to predict idle computing resources according to the base station traffic in different periods. Simulation results demonstrate that the practical performance of the context-aware vehicular task offloading (CAVTO) optimization scheme could reduce the system delay significantly.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.97-102
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• 2021

In this study, we developed the service that can efficiently making friends among college students in metaverse world. Metaverse technology has recently emerged as an important topic across the industry.' The development of virtual and augmented reality technologies, which have emerged as a new paradigm to drive the next generation of the Internet, is bringing us closer to the metaverse world. Metaverse is spreading around the gaming, entertainment, music, and content industries[1]. In particular, as non-face-to-face transitions have accelerated since the COVID-19 outbreak, lifestyles and industrial sites are rapidly changing beyond untacting to metaverseization, a three-dimensional virtual space. After discovering the needs of users through surveys and interviews, the research method added functions to the service that matched those needs. Users were pleased that they could make friends who matched their preferences and tastes, play like a game in a virtual world called metaverse, and customize their avatars to their liking. It was also very fresh to customize the goods so that they could be gifted and kept by themselves.