• Title/Summary/Keyword: High level laser

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An obstacle avoidance system of an unmanned aerial vehicle using a laser range finder

  • Kim, Hyun;Miwa, Masafumi;Shim, Joonhwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.7
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    • pp.737-742
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    • 2013
  • Recently, unmanned aircrafts for safe measurement in hazardous locations have been developed. In a method of operation of unmanned aircraft vehicles (UAV), there are two methods of manual control and automatic control. Small UAVs are used for low altitude surveillance flights where unknown obstacles can be encountered. Obstacle avoidance is one of the most challenging tasks which the UAV has to perform with high level of accuracy. In this study, we used a laser range finder as an obstacle detector in automatic navigation of unmanned aircraft to patrol the destination automatically. We proposed a system to avoid obstacles automatically by measuring the angle and distance of the obstacle using the laser range finder.

Fabrication of Polymer Laser Device by Two-Photon Induced Photopolymerization Technique

  • Yokoyama, Shiyoshi;Nakahama, Tatsuo;Miki, Hideki
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.231-231
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    • 2006
  • We fabricated a polymer sub-microstructure for optical device application by two-photon-induced laser lithography technique. Polymer pattern could be minimized as small as ${\sim}100\;nm$. The photopolymerization resin contains laser-dye, thus promising a high level of the optical gain. We utilized the lithography technique to the photonic crystal application, where the template of the two-dimensional photonic crystal was modified by polymer gain medium as defect-shape and line-shape orientations. Photonic band gap effect from polymer-doped photonic crystals is expected to exploit the application such as organic solid-state laser device.

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The Strain Measurement of Pure Aluminum Welded Zone by the Laser System (레이저 계측에 의한 순알루미늄 용접부의 스트레인 측정)

  • 성백섭;차용훈;이연신
    • Journal of Welding and Joining
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    • v.20 no.2
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    • pp.71-76
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    • 2002
  • Currently knowledge of strain in welds has mainly been obtained from strain gage method; that is directly attaching the gage to the most of the material. The very flew non-contact methods are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The paper is on the measurement of the strain caused by the characteristics and the temperature changes of the GTA welded zone employed with 3D ESPI system that is functionally modified through the laser ESPI system. This system may be applied the steel plate such as for the electronics, chemistry, flood instrument and electronic appliances.

The Strain Measurement of Butt Welded Zone by the Laser System (레이저 응용계측에 의한 용접부 스트레인 측정)

  • 성백섭;차용훈;박창언;김일수;김덕중;이연신;김인주
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.119-124
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    • 2001
  • Currently knowledge of strain in welds has mainly been obtained form strain gaging method:; that is directly attaching most of the material to the gate. The very few non-contact method are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The dissertation is on the measurement of the strain caused by the characteristics and the temperature changes of the TIG welded zone which is used with 3D ESPI system that is functionally modified through the laser ESPI system. This system employed the aluminum sheet-metal which are mainly used for the steel plate such as for the electronics, chemisry, food instrument and electronic appliances.

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The Strain Measurement of Butt Welded Zone by the Laser System (레이저 계측에 의한 맞대기 용접부의 스트레인 측정)

  • 성백섭;차용훈;박창언;김일수;김덕중;이연신;손준식
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.04a
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    • pp.155-161
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    • 2001
  • Currently knowledge of strain in welds has mainly been obtained from strain gaging method; that is directly attaching most of the material to the gage. The very few non-contact method are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The dissertation is on the measurement of the strain caused by the characteristics and the temperature changes of the TIG welded zone which is used with 3D ESPI system that is functionally modified through the laser ESPI system. This system employed the aluminum sheet-metal which are mainly used for the steel plate such as for the electronics, chemistry, food instrument and electronic appliances.

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Dynamic Characteristic Improvement of Laser Scanning Unit for Laser Beam Printer (레이저 프린터용 광스캔유닛(LSU) 의 동특성 개선)

  • 조문선;차덕순
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.189-193
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    • 2001
  • The performance of printer can be determined by the printing speed, noise level, printing quality which includes the resolution, regularity of printed matter and etc. Among them, printing quality mostly depends on the irregularity of the line spacing and dot size. The irregular line spacing and dot size in laser beam printer are mainly from the jitter which comes from the vibration of Organic Photo Conductive(OPC) drum and the Laser Scanning Unit(LSU). Jitter due to the vibration of LSU appears as high-frequency component which occurs 100-300$\mu\textrm{m}$ interval in printed matter and the causes of it can be estimated as the vibration of polygon motor, case, reflecting mirror and etc. In this paper, vibration characteristics of the LSU under development are investigated and the strategy for improvement of the dynamic characteristics is established and its validity is demonstrated.

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Development of docking system using laste slit beam (LSB를 이용한 Docking System 개발)

  • 김선호;박경택;최성락;변성태;이영석
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1999.10a
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    • pp.309-314
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    • 1999
  • The major movement block of the containers is range between apron and designation points on yard in container terminal. The yard tractor operated by human takes charge of it's movement in conventional container terminal. In unmanned container terminal, UCT(unmanned container transporter) has charge of the yard tractor's role and the navigation path is ordered from upper level control system. The unmanned container terminal facilities must have docking system that guided landing line to have high speed travelling and precision positioning in unmanned container terminal. The general method for docking uses the vision system with CCD camera, infra red, and laser. This paper describes the investigation for the developed docking method in view point of merit and demerit and introduces 속 result of developing the docking system with LSB(laser slit beam).

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Automatic Building Extraction Using LIDAR Data

  • Cho, Woo-Sug;Jwa, Yoon-Seok
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1137-1139
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    • 2003
  • This paper proposed a practical method for building detection and extraction using airborne laser scanning data. The proposed method consists mainly of two processes: low and high level processes. The major distinction from the previous approaches is that we introduce a concept of pseudogrid (or binning) into raw laser scanning data to avoid the loss of information and accuracy due to interpolation as well as to define the adjacency of neighboring laser point data and to speed up the processing time. The approach begins with pseudo-grid generation, noise removal, segmentation, grouping for building detection, linearization and simplification of building boundary , and building extraction in 3D vector format. To achieve the efficient processing, each step changes the domain of input data such as point and pseudo-grid accordingly. The experimental results shows that the proposed method is promising.

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Temperature thread multiscale finite element simulation of selective laser melting for the evaluation of process

  • Lee, Kang-Hyun;Yun, Gun Jin
    • Advances in aircraft and spacecraft science
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    • v.8 no.1
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    • pp.31-51
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    • 2021
  • Selective laser melting (SLM), one of the most widely used powder bed fusion (PBF) additive manufacturing (AM) technology, enables the fabrication of customized metallic parts with complex geometry by layer-by-layer fashion. However, SLM inherently poses several problems such as the discontinuities in the molten track and the steep temperature gradient resulting in a high degree of residual stress. To avoid such defects, thisstudy proposes a temperature thread multiscale model of SLM for the evaluation of the process at different scales. In microscale melt pool analysis, the laser beam parameters were evaluated based on the predicted melt pool morphology to check for lack-of-fusion or keyhole defects. The analysis results at microscale were then used to build an equivalent body heat flux model to obtain the residual stress distribution and the part distortions at the macroscale (part level). To identify the source of uneven heat dissipation, a liquid lifetime contour at macroscale was investigated. The predicted distortion was also experimentally validated showing a good agreement with the experimental measurement.

Laser Thermal Processing System for Creation of Low Temperature Polycrystalline Silicon using High Power DPSS Laser and Excimer Laser

  • Kim, Doh-Hoon;Kim, Dae-Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.647-650
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    • 2006
  • Low temperature polycrystalline silicon (LTPS) technology using a high power laser have been widely applied to thin film transistors (TFTs) for liquid crystal, organic light emitting diode (OLED) display, driver circuit for system on glass (SOG) and static random access memory (SRAM). Recently, the semiconductor industry is continuing its quest to create even more powerful CPU and memory chips. This requires increasing of individual device speed through the continual reduction of the minimum size of device features and increasing of device density on the chip. Moreover, the flat panel display industry also need to be brighter, with richer more vivid color, wider viewing angle, have faster video capability and be more durable at lower cost. Kornic Systems Co., Ltd. developed the $KORONA^{TM}$ LTP/GLTP series - an innovative production tool for fabricating flat panel displays and semiconductor devices - to meet these growing market demands and advance the volume production capabilities of flat panel displays and semiconductor industry. The $KORONA^{TM}\;LTP/GLTP$ series using DPSS laser and XeCl excimer laser is designed for the new generation of the wafer & FPD glass annealing processing equipment combining advanced low temperature poly-silicon (LTPS) crystallization technology and object-oriented software architecture with a semistandard graphical user interface (GUI). These leading edge systems show the superior annealing ability to the conventional other method. The $KORONA^{TM}\;LTP/GLTP$ series provides technical and economical benefits of advanced annealing solution to semiconductor and FPD production performance with an exceptional level of productivity. High throughput, low cost of ownership and optimized system efficiency brings the highest yield and lowest cost per wafer/glass on the annealing market.

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