• International conference on construction engineering and project management
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• 2022.06a
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• pp.344-352
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• 2022

Accurate indoor localization of construction workers and mobile assets is essential in safety management. Existing positioning methods based on GPS, wireless, vision, or sensor based RTLS are erroneous or expensive in large-scale indoor environments. Tightly coupled sensor fusion mitigates these limitations. This research paper proposes a state-of-the-art positioning methodology, addressing the existing limitations, by integrating Stereo Visual Inertial Odometry (SVIO) with fiducial landmarks called AprilTags. SVIO determines the relative position of the moving assets or workers from the initial starting point. This relative position is transformed to an absolute position when AprilTag placed at various entry points is decoded. The proposed solution is tested on the NVIDIA ISAAC SIM virtual environment, where the trajectory of the indoor moving forklift is estimated. The results show accurate localization of the moving asset within any indoor or underground environment. The system can be utilized in various use cases to increase productivity and improve safety at construction sites, contributing towards 1) indoor monitoring of man machinery coactivity for collision avoidance and 2) precise real-time knowledge of who is doing what and where.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.965-968
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• 2017

드론이라고도 불리는 소형 무인기는 비전 시스템을 대부분 갖추고 있어 비전을 응용한 기술이 적합한 플랫폼이며 특히 랜드 마크 기반 위치 추적 방법은 드론과 지상 로봇과 같은 다른 플랫폼 간의 협업을 위한 효율적인 방법 중 하나이다. 본 논문에서는 드론과 지상 로봇의 협업 시스템을 위하여 기준 마커를 검출하는 연구에 대하여 서술한다. 기준 마커 중 하나인 ArUco는 바코드보다 간단한 내부 코드를 가지고 있다. 기준 마커의 카메라 캘리브레이션을 통하여 카메라와 마커의 자세 추정이 가능하다. 성능 평가 실험을 통하여 형태가 간단한 마커, AprilTags, ArUco 간 성능 비교를 하였고 92%의 정확도를 얻어내었으며 ArUco의 적합한 이진화 알고리즘을 제시하였다.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.115-132
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• 2012

The purpose of this study is to examine the current status of user-contributed reviews for the Next Generation Library Catalogs, and the potential impact of user reviews available from the external sources, including Amazon.com and GoodReads.com. During the period of February 16th through April 4th, 2012, the number of holding libraries and user-contributed reviews, tags and reading lists of ten selected books were examined from the WorldCat. Also the user-contributed reviews for the same books available from Amazon.com and GoodReads.com were examined, and a case of reviews for one book was analyzed. The result shows that only a few users participated in the WorldCat, and user-contributed reviews were rarely used, when compared with tags or reading lists. Several hundred to thousand user-contributed reviews for the same books were available from Amazon.com and GoodReads.com directly linked with bibliographic records. A case of one book from Amazon.com reveals the possibility of distorting the function of user-contribution. With the introduction of the function of user-contribution, it is expected that its growth rate should be carefully observed and its potential impact on users should be thoroughly and systematically analyzed in the near future.