• Title/Summary/Keyword: Li-Hak

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Development of autonomous patrol robot using SLAM and LiDAR (SLAM알고리즘과 LiDAR를 이용한 자율주행 로봇 개발)

  • Yun, Tae-Jin;Kim, Min-Gu;Kim, Min;Mun, Dong-Ho;Lee, Sang-Hak
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2020.01a
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    • pp.289-290
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    • 2020

  • 본 논문에서는 Turtlebot burger3와 라즈베리파이의 OpenCV, OpenCR보드를 이용하여 ROS상에서 SLAM알고리즘을 구현하여 자율 주행 순찰이 가능한 로봇을 개발한다. 특히, 라즈베리파이 카메라에 OpenCV를 이용하여 사람 얼굴 인식이 가능하게 하여 순찰 시 카메라로 순찰 정보를 제공 할 수 있게 한다. 또한, 로봇에 탑재된 LiDAR는 SLAM 알고리즘을 이용하여 주변의 환경을 매핑하여 장애물을 회피할 수 있는 경로를 탐색할 수 있도록 한다. 개발 기술들을 통하여 사람 대신에 로봇이 경비 구역의 침입자 촬영을 하고, 원격제어가 가능한 시스템으로 다양한 분야에 로봇 제어 기술에 활용하고자 한다.

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Effects of the Czochralski growth parameters on the growth of $LiNbO_3$ crystals ($LiNbO_3$단결정에 미치는 CZ 성장조건의 영향)

  • Lee, Sang-Hak;Yun, Ui-Park
    • Korean Journal of Materials Research
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    • v.2 no.1
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    • pp.52-57
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    • 1992

  • The macro defects of $LiNbO_3$ crystals grown by the Czochralski method were strongly influenced by the single crystal growth parameters such as growth rate, thermal gradient and crystal rotation rate. The optimum growth conditions of a $LiNbO_3$ single crystal with 1" in diameter were $70~100^{circ}C/cm$ temperature gradient, 5~10 mm/hr growth rate and 40 rpm crystal rotation rate. In these conditions, we could grow crystals which had no cellular structure with easy diameter control, and any crack was not formed after the crystal was cooled.oled.

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Monitoring analysis of Model Slope by using Terrestrial LiDAR data (지상LiDAR자료를 이용한 모형사면의 모니터링)

  • Kim, Sung-Hak;Choi, Seung-Pil;Yang, In-Tae
    • Journal of Korean Society for Geospatial Information Science
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    • v.16 no.4
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    • pp.17-23
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    • 2008

  • A model slope was made to work out a way of detecting the sign of the occurrence of landslides and monitoring analysis was conducted to grasp the slope displacement of Terrestrial LiDAR equipment. As a result, the image of slope displacement could be monitored quickly and the accuracy of monitoring analysis was a deviation of 0.007m, 0.006m and 0.006m on average based on the figures prior to displacement after the first, second and third displacements, respectively. As the figures represent a very small deviation, they will be able to be used helpfully in measuring the displacement of actual slope in the future.

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7Li MAS NMR studies of Li4P2O7 and LiFePO4 materials (LiFePO4와 Li4P2O7의 7Li MAS NMR 특성 연구)

  • Han, Doug-Young;Park, Nam-Sin;Lee, Sang-Hyuk;Lee, Hak-Man;Kim, Chang-Sam
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.1
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    • pp.15-20
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    • 2011

  • [ $^7Li$ ]Magic Angle Spinning (MAS) NMR spectroscopy has been used to study the lithium local environments in $Li_4P_2O_7$ and$LiFePO_4$ materials. The purpose of this study was to know the structure of the solid electrolyte interphase (SEI) in lithium ion cells composed of $LiFePO_4$ as cathode material. $Li_4P_2O_7$ and $LiFePO_4$ were prepared by a solid-state reaction. The $^7Li$ MAS NMR experiments were carried out at variable temperatures in order to observe the local structure changes at the temperatures in $Li_4P_2O_7$ system. The $^7Li$ MAS NMR spectra of in $Li_4P_2O_7$ indicate that the lithium local environments in $Li_4P_2O_7$ were not changed in the temperature range between $27^{\circ}C$ and $97^{\circ}C$ Through this work, we confirmed that the small amount of $Li_4P_2O_7$ less than 5.0 wt% in $LiFePO_4$ could be clearly measured by the $^7Li$ MAS NMR spectroscopy at high spinning rate over than 11 kHz.

  • https://doi.org/10.6111/JKCGCT.2011.21.1.015 인용 PDF KSCI