• Title/Summary/Keyword: STL

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Application of Delaunay Triangulation on RP (Delaunay삼각형 분할법의 RP에의 응용)

  • 명태식;채희창;김옥현
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.3
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    • pp.35-41
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    • 1999
  • STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

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A Study on RP Part Production Using Intersecting Circle Approximation Method (교차다각형법에 의한 원 근사 방법을 적용한 RP Part 제작에 관한 연구)

  • 신근하
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.1
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    • pp.68-74
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    • 2000
  • The STL file format is an approximation of 3-D model with triangular facets. STL is a standard input file format of Rapid Prototyping(RP) equipment In computer graphics a circle has been approximated with an inscribed polygon which causes an error between the real and approximated circles. In this study an intersecting polygon has been used to approximate the circle and applied to produce more accurate RP part. The newly proposed method shows it's excellence in part accuracy.

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Effect of the measurement error of reverberation time on the STL (잔향시간 측정 오차의 차음손실에 대한 영향)

  • 신성환;이정권;강현주
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1099-1103
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    • 2001
  • In room acoustics, reverberation time (RT) is the most important and general factor that represents character of room or inner space. However, RT, especially in low frequency range, can have the different value according to the measuring points and methods. This study comprehends the cause of error occurring dominantly in low frequency range when RT is measured and examines that the each error of RT measured in the cabin and reverberation chamber having different properties, influences what extent on sound transmission loss (STL)

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Development of a Dedicated CAM System for Human Bust Machining (흉상환조가공 전용 CAM 시스템 개발)

  • 정회민;박준철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.7-10
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    • 2001
  • We have developed a prototype dedicated CAM system for machining a human bust that is not a relief. The input is STL file format, and the output is NC-codes for machining on a 3-axis general purpose CNC milling machine with an index table attached. Main modules are STL import, STL transformation, modeling jig/fixture, master model generation, and calculation of machining area. System architecture is proposed and main modules are briefly described. We adopted the angle between tool-axis and the surface normal vector to calculate machining area, and tested at several degrees.

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The Application of Delaunay Triangulation on RP (Delaunay 삼각형 분합법의 RP에의 응용)

  • 김대원
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.129-134
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    • 1998
  • STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

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A Study on RP Part Production Using New Circle Approximation Method (새로운 원 근사방법을 적용한 RP Part 제작에 관한 연구)

  • 홍민성;신근하;박시준;최상련;오철호
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.81-86
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    • 1999
  • The STL file format is an approximation of 3-D model with triangular facets. STL is a standard input file format of Rapid Prototyping(RP) equipment. In computer graphics, a circle has been approximated with an inscribed polygon, which causes an error between the real and approximated circles. In this study, an intersecting polygon has been used to approximate the circle and applied to produce more accurate RP part. The newly proposed method shows it's excellence in part accuracy.

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Improvement of Sound Transmission Loss of Ship's Bulkhead at Low Frequency Range (선박 격벽의 저주파수 대역 차음성능 향상에 관한 연구)

  • Kim, Sung-Hoon;Joo, Won-Ho;Bae, Jong-Gug
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.167-168
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    • 2009
  • The noise sources in ship and offshore structure have an influence on adjacent receiving area through a partition between noise sources and receiving area. The partition in ship is usually made of stiffened plate. Sound transmission loss (STL) of the partition at high frequency could be improved by additional installation of insulation or wall panel. At low frequency, however, it is very difficult and needs an increase of plate thickness which causes a considerable weight increase of ship. In this paper, we have investigated the effect of the bulkhead boundary condition. From measurement result, we found that the bulkhead boundary condition can affect a lot in STL, especially at low frequency range. Finally, we get the 5dB increase in STL through the modification of boundary condition.

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Evaluation on machining accuracy according to convergence angle and radius of curvature value used for fabricating custom abutments (맞춤형 지대주 제작에 사용되는 수렴 각과 곡률 반경의 값에 따른 가공 정확도 평가)

  • Hong, Min-Ho;Choi, Sung-Min;Kwon, Tae-Yub
    • Korean Journal of Dental Materials
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    • v.44 no.4
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    • pp.329-336
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    • 2017
  • This study evaluates the machining accuracy of the custom abutment design according to the selected convergence angle and radius of curvature value in the CAD program. Ten custom abutments were designed based on dental CAD. And then, the fabricated custom abutment was scanned ten times using a contact scanner. The data of the scanned custom abutment was saved as "Test STL" file. The Geomagic studio software was used to superposition each exported as an "Test STL" file with the CAD-reference-model STL file (CRM) specified by the same name. In the experimental results, the A8 group (convergence angle $8^{\circ}$) showed lower error than the A4 group (convergence angle $4^{\circ}$) . In addition, the higher the radius of curvature, the less error in the top and chamfer regions of the custom abutment (p< 0.05). Overall, the convergence angle and radius of curvature value in the custom abutment design were found to affect the machining accuracy.

Position and Measurement Performance Analysis of GPS Receiver applied LQG based Vector Tracking Loop (LQG 기반 벡터 추적 루프를 적용한 GPS 수신기의 위치 및 측정치 성능 분석)

  • Park, Min-Huck;Jeon, Sang-Hoon;Kim, Chong-Won;Kee, Chang-Don;Seo, Seung-Woo;Jang, Jae-Gyu;So, Hyoung-Min;Park, Jun-Pyo
    • Journal of Advanced Navigation Technology
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    • v.21 no.1
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    • pp.43-49
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    • 2017
  • Generally, loop filter based scalar tracking loops (LF-STL) have been used for global positioning system (GPS) signal tracking algorithm. This paper introduces the accuracy and robustness of linear-quadratic-Gaussian based vector tracking loop (LQG-VTL) algorithm instead of LF-STL. To verify the accuracy of LQG-VTL, we confirm that the measurements estimation errors of the LQG based scalar tracking loops (LQG-STL) are improved by more than 60 % compared to LF-STL. Also, when LQG-VTL is used, measurements estimation errors decrease compared to LQG-STL, and position/velocity estimation errors also decrease as the number of satellites increases. To verify the robustness of LQG-VTL, we confirm that LQG-VTL can estimate position/velocity and measurements successively compared to LF-STL in temporal signal attenuation of 30 dB-Hz during 4 seconds.

System Design for Detecting Abnormal Data in the Monitoring Sensor Network (환경 모니터링 센서 네트워크에서의 이상 데이터 검출을 위한 시스템 설계)

  • Park, Soo-Yong;Jeon, Min Jae;Shin, Yong-Tae
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.253-255
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    • 2019
  • 센서 네트워크는 IoT, 스마트 팜 등의 다양한 분야에 활용되고 있다. 그러나 센서 자체의 결함과 환경적인 요인으로 인해 데이터의 변화가 발생하는 단점을 가지고 있다. 제안하는 시스템은 기존의 센서 네트워크에 중앙 서버를 배치하고 중앙 서버에 STL Module를 추가한다. STL Module은 센서로부터 측정된 데이터를 분석하고 이상 데이터를 검출하여 제거한다. 중앙 서버에 추가적으로 Web Server를 구축하여 관리자가 실시간으로 모니터링할 수 있다.