• Title/Summary/Keyword: 직각도

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Wind Tunnel Tests for Evaluation of Sliding and Overturning Velocities on Shipping Containers (선박 운송용 컨테이너의 활동 및 전도발생 풍속 평가를 위한 풍동실험)

  • Kim, Wonsul;Yi, Jin-Hak;Yoshida, Akihito
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.5
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    • pp.260-268
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    • 2017
  • In this study, wind characteristics of a shipping container were investigated through the wind tunnel test (high-frequency force balance test), and damage occurrence velocities of various containers with weights were evaluated based on results of the wind tunnel tests. As a result, mean wind force coefficients acting on containers in x-direction increased in the order of 12ft, 20ft, 40ft and 40ft high cube. On the other hand, mean wind force coefficients at y-direction increased in the order of 40ft high cube, 40ft, 20ft and 12ft. It was suggested that the shear layer separated from the corner of windward surface of the container is reattached on the sides of it, and then the mean wind force coefficient is weaker. As a result of the damage occurrence velocity on containers with weights, it was found that the probability of occurrence of sliding is higher rather than that of overturning. Further, the most unfavorable container was 40ft high cube, and the sliding and overturning occurrence velocities were 20.4 m/s and 26.8 m/s, respectively. Furthermore, the regression formula for sliding and overturing occurrence velocitys were proposed based on the results of relationship between weights of containers and damage occurrence velocities. These results are expected to be useful in establishing a guideline for external force estimation acting on container securing equipment and stacking way.

Sonolysis of Trichloroethylene in the Multi Ultrasound Irradiation Reactor (다중 초음파 조사 반응조에서의 TCE의 초음파 분해)

  • Lee, Min-Ju;Oh, Je-Ill
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.10
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    • pp.873-882
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    • 2009
  • Sonolysis of TCE (Trichloroethylene) was performed in 584 kHz rectangular reactor. At first, the effect of acoustic power and aqueous temperature which are both important factors to operate ultrasound system on sonolysis of TCE were examined under one side irradiation condition. First degradation rate constants of TCE and chloride yields were increased with increasing acoustic power from 100 to 300 W. And increasing the aqeuous temperature resulted in the increase of first degradation rate constants of TCE and the decrease of chloride yield. Sonolysis of TCE was performed under multi ultrasound irradiation conditions that total acoustic power of 300 W was distributed according to the number of irradiation sides. First degradation rate constants of TCE followed the order 4 sides > 3 sides > 1 side > 2 sides (parallel) > 2 sides (orthogonal). When comparing the experimental results under parallel and orthogonal irradiation conditions of 2 sides with 300 and 450 W, first degradation rate constants of TCE were similar, while production rate constants of hydrogen peroxide were more higher at parallel conditions compared to orthogonal conditions.

An Experiment of Structural Performance of Expansion Joint with Rotation Finger (가변형 핑거 조인트를 가지는 신축이음장치의 구조 성능 실험)

  • Yoo, Sung won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.170-175
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    • 2018
  • For the seismic performance, it is necessary to prevent the destruction of the expansion joint device due to the appropriate deformation of the expansion joint device due to the seismic force. Recently, the hinge is installed on the fingering of the expansion joint device in Korea, New products are being developed. In this paper, we have experimentally evaluated the real scale resistance of the expansion joints with rotational finger joints against load at right angle to the bridge axis. Experimental results show that the maximum horizontal displacement is about 21.1mm for conventional stretch joints and 51.00mm for seismic stretch joints. It is presumed that the existing expansion joint test specimen is resistant to the load in a direction perpendicular to the throat axis, and then the bending and shear deformation of the finger are excessively generated and the fracture phenomenon is likely to occur. On the other hand, in the case of the seismic expansion joint, the deformation of the load due to the load is absorbed by the hinge of the finger with respect to the load in the direction perpendicular to the throat, so that only horizontal deformation in the direction of load action.

Comparative Analysis of Focal Length Bias for Three Different Line Scanners (초점거리 편의가 지상 정확도에 미치는 영향 비교 연구 - 세가지 라인 스캐너를 대상으로 -)

  • Kim, Changjae
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.4_1
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    • pp.363-371
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    • 2014
  • Most space-borne optical scanning systems adopt linear arrayconfigurations. The well-knownthree different types of space-borne sensors arealong-track line scanner, across-track linescanner, and three line scanner. To acquire accurate location information of an object on the ground withthose sensors, the exterior and interior orientation parameters are critical factors for both of space-borne and airborne missions. Since the imaging geometry of sensors mightchange time to time due to thermal influence, vibration, and wind, it is very important to analyze the Interior Orientation Parameters (IOP) effects on the ground. The experiments based on synthetic datasets arecarried out while the focal length biases are changing. Also, both high and low altitudes of the imagingsensor were applied. In case with the along-track line scanner, the focal length bias caused errors along the scanline direction. In the other case with the across-track one, the focal length bias caused errors alongthe scan line and vertical directions. Lastly, vertical errors were observed in the case ofthree-line scanner. Those results from this study will be able to provide the guideline for developing new linearsensors, so as for improving the accuracy of laboratory or in-flight sensor calibrations.

Convergence Comparison of Linear Oscillating Electric Machines (리니어 오실레이팅 전기기기의 비교 연구)

  • Jeong, Sung-In;Eom, Sang In
    • Journal of the Korea Convergence Society
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    • v.12 no.12
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    • pp.273-280
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    • 2021
  • This paper presents the results of study of linear oscillating electric machine; Cartesian, cylindrical type with permanent magnet, flux reversal, cylindrical reluctance, and transverse flux type. The focus of the work is the suggestion of the characteristics and design process of propose topology, respectively. First of all, there are five types of the proposed to this study on the basis of the existing literatures; Cartesian type, cylindrical type, flux reversal type, cylindrical reluctance type, and transverse flux type. All topology is achieved using equivalent magnetic circuit considering leakage elements as initial modeling. Cartesian type is investigated by number of phases and number of pole pairs using optimal process. A cylindrical type is described by number of phases and displacement of stroke. The flux reversal type is proposed based on the symmetrical and non symmetrical stator cores of the surface mounted PMs mover, and non slanted PMs and slanted PMs of the flux concentrating PMs mover. A cylindrical reluctance type is studied by the shape of mover teeth in geometric aspect to reduce force ripple and increase magnetic flux. A transverse flux type is considered by dividing the transverse flux electric excited and the transverse flux permanent magnet excited. It is significant that the study gives a design rules and features of linear oscillating electric machine.

SoC IP design for Perpendicular Coordinate Robot & Image Capture (직각좌표로봇 및 영상캡쳐를 위한 SoC IP 설계구현)

  • Park Jong-Seong;Moon Cheol-Hong
    • Proceedings of the IEEK Conference
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    • 2004.06b
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    • pp.403-406
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    • 2004
  • This paper describes an IP design and implementation of a complicated hardware to System on a Chip(SoC) to simplify the complicated system. As using SoC, hardware and software can be designed and verified both. This paper describes an image capturing IP and a perpendcular coordinate robot IP that can move on x, y coordinates. 240$\ast$320 TFT-LCD is used to display images.

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리브조직의 편성방법에 따른 구조적 특성과 역학적 특성에 관한 연구 -양모 섬유를 중심으로-

  • 기희숙;서미아
    • Proceedings of the Costume Culture Conference
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    • 2004.04a
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    • pp.113-115
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    • 2004
  • 리브조직은 위편성물의 기본 조직으로 앞코와 뒤코의 직각 혹은 그것에 가까운 각도의 조합에 의해 겉뜨기와 안뜨기가 교대로 편성되어 코스방향으로 골을 형성하는 조직으로 주로 단이나 몸판에 사용된다. 주로 단에는 1×1, 2×1 rib을 사용하고 몸판에는 3바늘 이상 골을 형성하는 리브조직을 주로 사용하지만 2×2 , 3×3 rib등 여러 가지가 사용된다 앞코와 앞코끼리, 뒤코와 뒤코끼리 서로 붙어 있어 단면을 보면 뱀 껍질과 같은 모양처럼 보이는 데 이러한 형상은 다른 조직에 비해 편폭이 좁게 되고 신축성을 좋게 하는 중요한 성질이 된다. (중략)

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Transmission and Rendering of Massive Terrain Data in Network Environment (네트웍 환경에서의 대규모 지형 데이터 전송 및 렌더링)

  • 김대성;한정현
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.04c
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    • pp.184-186
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    • 2003
  • 본 논문에서는 대규모 지형 데이터를 이용한 네트웍 환경에서의 지형 탐색을 위한 다중 해상도 기법과 prefetching 기법을 제안한다. 지형 렌더링에 널리 사용되는 직각이등변 삼각형 메쉬 형태의 DEM 데이터를 정삼각형 메친 데이터로 재구성한 뒤, 이를 다중 해상도로 구조화하여. 네트웍 환경에서의 주요 문제점인 대역폭과 지연 문제를 보완하였다. 본 기법은 3차원 지형 데이터를 이용한 온라인 게임 등에 응용될 수 있다.

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Development of Computer Modules for Precision Measurement of Geometric Tolerances (기하학적 공차의 정밀측정을 위한 컴퓨터 모듈개발)

  • 박희재;황상욱
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.3
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    • pp.205-219
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    • 1993
  • 제품의 기하학적 칫수 공차는 생산제품의 품질관리에 매우 종요하며, 측정기기의 발달과 함께, 컴퓨터를 이용한 기하하적 공차 해석의 수요와 경향은 늘고 있는 추세이다. 본 논문에서는, ISO의 공차 정의에 기초한 공차들(진직도공차, 편평도공차, 진원도공차, 평행도공차, 직각도공차, 윤곽공차)을 해석할 수 있는 컴퓨터 모듈이 개발되었다. 특히 윤곽공차의 경우 측정프로브의 반경의 효과가 배제되는 알고리즘을 개발하였다. 개발된 컴퓨터 모듈을 실제적인 측정작업에 적용하였으며, 고종도와 고효율성을 보임을 입증하였다.

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Scaling analysis of Core Flow Pattern in a Low-Aspect Ratio Rectangular Enclosure -( II ) End-Driven flow Regime- (종횡비가 낮은 직각형 밀폐용기 내의 코어흐름 형태에 관한 해석 -( II ) 운동력이 양단에 존재하는 경우-)

  • 이진호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.8 no.4
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    • pp.375-384
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    • 1984
  • 본 연구에서는 종횡비가 낮은 직사각형 밀폐용기 내에 Rayleigh수가 충분히 커서 흐름의 운동력이 용기 양단에 존재하는 경우에 PartⅠ에서 개발된 해석적인 모델 을 근거한 scaling analysis를 통해 그 내부 흐름 형태를 정성적으로 예측, 기존의 결 과와 비교, 검토하였다. 해석결과, Prandtl수에 따라 여러가지 내부 흐름 형태가 존 재할 수 있음이 밝혀졌으며 용기 내 뚜렷한 경계층 흐름이 존재하기 위한 필요조건도 아울러 얻어졌다.