• Title/Summary/Keyword: 어안

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A Study on Stress Analysis and Fatigue Behaviors of Carbonitrided Cr-Mo(SCM415) Steel - About the Prediction of Fatigue Strength - (침탄질화 처리된 크롬-몰리브덴(SCM415)강의 피로거동 및 응력해석 (2) -피로강도의 예측을 중심으로-)

  • 송삼홍;이상훈
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.5
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    • pp.160-167
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    • 2000
  • In this research, the fatigue behaviors of carbonitrided Cr-Mo(SCM415) steel are examined. From fatigue test results, we propose a modified fatigue strength evaluation model and modified formulae. That is, we develop improved models fur evaluating and predicting the fatigue strength of carbonitrided SCM415 by modifying specific terms in the Murakami and Endo's model which is the representative fatigue strength evaluation formulae fur high strength steel.

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A Bump Mapping Method Using Camera Lens (카메라 렌즈를 이용한 범프 맵핑)

  • Koh, Wook
    • Journal of the Korea Computer Graphics Society
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    • v.3 no.1
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    • pp.9-15
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    • 1997
  • Most rendering research has concentrated on two sub-problems: modeling the reflection of light sources, and calculating the direct and indirect illumination from light sources and other surfaces. As Kolb wrote in [1], the camera and lens model is an important key component of a rendering system. In this paper we describe a bump-mapping method using camera lens. It allows another level of control in rendering. We developed an efficient framework to develop customized bump mapping lens and combine with other sequence of lens elements to create various effects as shown in Figure 2,3,4,5.

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A Study on the Distribution of Internal Inclusions and the Fatigue Strength of Induction Surface Hardened Steel (고주파 표면경화재의 내부개재물의 분포와 피로강도에 관한 연구)

  • Song, Sam-Hong;Choi, Byoung-Ho
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.333-338
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    • 2000
  • Induction surface hardening is widely used to enhance local strength and hardness. However, most research is only to have a focus on fatigue life and fatigue behavior is not so much studied. So, in this study, Cr-Mo steel alloy(SCM440) was used to show the effect of residual stress and micro hole on the fatigue strength for base metal and induction surface hardened specimen. In addition, the fatigue characteristic between surface hardened and fully hardened steel is somewhat different. It is caused by hardness distribution, residual stress and inclusions etc.. Crack origins are generally micro inclusions for the high strength steel. So, the distribution of inclusions is analyzed statistically.

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A Study on Stress Analysis and Fatigue Behaviors of Carbonitried Cr-Mo(SCM415) Steel -About Various Factors Having an Effect on Fatigue Strength- (침탄질화 처리된 크롬-몰리브덴(SCM415)강의 피로거동 및 응력해석 -피로강도에 영향을 주는 제 인자를 중심으로 -)

  • 송삼홍;이상훈
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.8
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    • pp.135-144
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    • 1998
  • In this research, the fatigue behaviors of Cr-Mo(SCM415) steel and carbonitrided CrMo(SCM415) steel are examined. The description of experiments in detail as follows. For SCM415 and carbonitried Cr-Mo(SCM415) steel, smooth specimens and hole defected specimens are fabricated and tested under a rotary bending tester, respectively. By performing the rotary bending fatigue test for smooth and hole defected specimens, the characteristics of the fatigue strength are examined for parameters such as tensile strength, hardness at surface, and residual stresses.

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Improvement of Fatigue Strength and Characteristics of Nitrided ICr-lMo-0.25V turbine Rotor Steels at evaluated temperature (질화처리된 1Cr-1Mo-0.25V강의 고온화 피로특성평가)

  • 서창민;황병원;서창희
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.357-362
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    • 2001
  • The purpose of this study is to investigate the effect of nitriding on the fatigue strength and fatigue life of turbine rotor steel (ICr-lMo-0.25V), and acquire data on the fatigue strength of nitrided turbine rotor steel at high temperature (538$^{\circ}C$). Specimens were nitrided with various layer thicknesses (160$\mu$m, 270$\mu$m and 290$\mu$m) using the nitemper method. A microstructure analysis, microhardness test, surface roughness test, and fracture surface analysis were also carried out at room temperature in order to investigate the mechanical properties of the nitrided specimens.

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Deep Learning based Object Detector for Vehicle Recognition on Images Acquired with Fisheye Lens Cameras (어안렌즈 카메라로 획득한 영상에서 차량 인식을 위한 딥러닝 기반 객체 검출기)

  • Hieu, Tang Quang;Yeon, Sungho;Kim, Jaemin
    • Journal of Korea Multimedia Society
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    • v.22 no.2
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    • pp.128-135
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    • 2019
  • This paper presents a deep learning-based object detection method for recognizing vehicles in images acquired through cameras installed on ceiling of underground parking lot. First, we present an image enhancement method, which improves vehicle detection performance under dark lighting environment. Second, we present a new CNN-based multiscale classifiers for detecting vehicles in images acquired through cameras with fisheye lens. Experiments show that the presented vehicle detector has better performance than the conventional ones.

Development of Camera Module for Vehicle Safety Support (차량 안전 지원용 카메라 모듈 개발)

  • Shin, Seong-Yoon;Cho, Seung-Pyo;Shin, Kwang-Seong;Lee, Hyun-Chang
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.05a
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    • pp.672-673
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    • 2022
  • In this paper, we discuss a camera that is fixed in the same view as the TOF sensor and can be installed horizontally in the vehicle's moving direction. This camera applies 1280×720 resolution to improve object recognition accuracy, outputs images at 30fps, and can apply a wide-angle fisheye lens of 180° or more.

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3D Map Construction from Spherical Video using Fisheye ORB-SLAM Algorithm (어안 ORB-SLAM 알고리즘을 사용한 구면 비디오로부터의 3D 맵 생성)

  • Kim, Ki-Sik;Park, Jong-Seung
    • Proceedings of the Korea Information Processing Society Conference
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    • 2020.11a
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    • pp.1080-1083
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    • 2020
  • 본 논문에서는 구면 파노라마를 기반으로 하는 SLAM 시스템을 제안한다. Vision SLAM은 촬영하는 시야각이 넓을수록 적은 프레임으로도 주변을 빠르게 파악할 수 있고, 많은 양의 주변 데이터를 이용해 더욱 안정적인 추정이 가능하다. 구면 파노라마 비디오는 가장 화각이 넓은 영상으로, 모든 방향을 활용할 수 있기 때문에 Fisheye 영상보다 더욱 빠르게 3D 맵을 확장해나갈 수 있다. 기존의 시스템 중 Fisheye 영상을 기반으로 하는 시스템은 전면 광각만을 수용할 수 있기 때문에 구면 파노라마를 입력으로 하는 경우보다 적용 범위가 줄어들게 된다. 본 논문에서는 기존에 Fisheye 비디오를 기반으로 하는 SLAM 시스템을 구면 파노라마의 영역으로 확장하는 방법을 제안한다. 제안 방법은 카메라의 투영 모델이 요구하는 파라미터를 정확히 계산하고, Dual Fisheye Model을 통해 모든 시야각을 손실 없이 활용한다.

Mobile Robot Localization and Mapping using Scale-Invariant Features (스케일 불변 특징을 이용한 이동 로봇의 위치 추정 및 매핑)

  • Lee, Jong-Shill;Shen, Dong-Fan;Kwon, Oh-Sang;Lee, Eung-Hyuk;Hong, Seung-Hong
    • Journal of IKEEE
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    • v.9 no.1 s.16
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    • pp.7-18
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    • 2005
  • A key component of an autonomous mobile robot is to localize itself accurately and build a map of the environment simultaneously. In this paper, we propose a vision-based mobile robot localization and mapping algorithm using scale-invariant features. A camera with fisheye lens facing toward to ceiling is attached to the robot to acquire high-level features with scale invariance. These features are used in map building and localization process. As pre-processing, input images from fisheye lens are calibrated to remove radial distortion then labeling and convex hull techniques are used to segment ceiling region from wall region. At initial map building process, features are calculated for segmented regions and stored in map database. Features are continuously calculated from sequential input images and matched against existing map until map building process is finished. If features are not matched, they are added to the existing map. Localization is done simultaneously with feature matching at map building process. Localization. is performed when features are matched with existing map and map building database is updated at same time. The proposed method can perform a map building in 2 minutes on $50m^2$ area. The positioning accuracy is ${\pm}13cm$, the average error on robot angle with the positioning is ${\pm}3$ degree.

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Fatigue Characteristic of Bearing Steel(STB2) in Gigacycle (베어링강의 기가사이클 피로 특성에 관한 연구)

  • KIM SANG-CHUN;SUH CHANG-MIN;HWANG BYUNG-WON;LEE TAE-SUNG
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.370-375
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    • 2004
  • Fatigue tests were carried out to find the fatigue characteristics in the super-long life range by using a cantilever type rotational bending fatigue test machine. Three kinds of specimen in bearing steels with the quenched and tempered in air (A and B, B: shot peened after heal treatment) and under vacuum conditions(C:non-shot peened)were tested in this study. S-N curves obtained from fatigue tests of C specimen tend to come dawn again in the super-long life range due to fish-eye type cracking, while most of A and B specimens fractured by surface defects such as scratches and slip lines. This duplex S-N behavior for the high strength steels have to be reviewed by the change of fracture modes.

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