• 제어로봇시스템학회논문지
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• 제17권2호
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• pp.176-182
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• 2011

Industrial network, often referred to as fieldbus, becomes an indispensable component for intelligent manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers, numerous fieldbus protocols have been developed. But, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. As an alternative to fieldbus, the Ethernet (IEEE 802.3) technology is being adapted to the industrial environment. However, the crucial technical obstacle of Ethernet is its non-deterministic behavior that cannot satisfy the real-time requirements. Recently, the EtherCAT protocol becomes a very promising alternative for real-time industrial application due to the elimination of uncertainties in Ethernet. This paper focuses on the implementation of the IEC 61800 based real-time EtherCAT network for multi-axis smart driver. To demonstrate the feasibility of the implemented EtherCAT slave module, its synchronization performance is evaluated on the experimental EtherCAT testbed with a single axis smart driver.

• KIEAE Journal
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• 제11권1호
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• pp.9-14
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• 2011

Currently, the multi-residential apartments used in Korea are mostly bearing wall apartments which don't satisfy consumers for the lack of architectural plan flexibility. And due to remodelling-incompatible, bearing wall apartments have to be reconstructed. It is, thus, necessary to develop multi-residential apartments utilizing composite beam that can replace the conventional bearing wall-type apartment buildings. Composite beams proposed in this paper ensure modification of space and quality control, while the floor heights are maintained at the same floor height as in bearing wall structures. This study analyzes the experimental behavior of composite beams with proper combination of structural steel, reinforced concrete, and precast concrete. By comparing with the theoretical analysis and experimental results, the accuracy of flexural moment capacity and neutral axis was evaluated. The experiments were performed by two simply-supported specimens using loading and unloading. When the analysis results were compared with the experimental results, the flexural moment capacity of the composite beam was shown with an error of approximately -0.5 to 0.1% at the maximum load limit state.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.487-493
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• 1998

Camera calibration is the process of determining the coordinate relationship between a camera image and its real world space. Accurate calibration of a camera is necessary for the applications that involve quantitative measurement of camera images. However, if the camera plane is parallel or near parallel to the calibration board on which 2 dimensional objects are defined(this is called "ill-conditioned"), existing solution procedures are not well applied. In this paper, we propose a neural network-based approach to camera calibration for 2D images formed by a mono-camera or a pair of cameras. Multi-layer perceptrons are developed to transform the coordinates of each image point to the world coordinates. The validity of the approach is tested with data points which cover the whole 2D space concerned. Experimental results for both mono-camera and stereo-camera cases indicate that the proposed approach is comparable to Tsai's method［8］. Especially for the stereo camera case, the approach works better than the Tsai's method as the angle between the camera optical axis and the Z-axis increases. Therefore, we believe the approach could be an alternative solution procedure for the ill -conditioned camera calibration.libration.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.271-272
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• 2006

This paper presented a new experimental gain tuning technique for a Multi-Axis Servo System. First, the investigation for proportional gain of velocity control loop by using a Dynamic Signal Analyzer (DSA) was performed. Using the FUNCTION characteristic of DSA based on the Bode plot, the Bode plot of open loop transfer function was obtained. In turn, the integral gain of a servo controller can be found out by using the Integration time constant extracted from the Bode plot of open loop transfer function. In the meanwhile, the positional gain of the servo controller has been obtained by using the Bode plot of the closed loop transfer function. We have also proposed the technique to find out an optimal parameter of a notch filter, which has a great influence on vibration reduction, by using the damping factor extracted from the Bode plot of closed loop transfer function.

• 한국전자파학회논문지
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• 제13권1호
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• pp.53-59
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• 2002

본 논문에서는 다중대역 피드를 위한 직교모느 변환기를 설계하였다. 직교모드 변환기의 전체적인 모양은 사각 테이퍼진 형태이고, 18~20 GHz에서 우원편파와 좌원편파를 발생시키기 위해 테이퍼 부분에 2개의 측면 포트를 두고, 직선포트는 30~45 GHz의 광대역에서 -20 dB 이하의 반사계수와 15 dB 이하의 분리도를 가지도록 설계하였다. 직선포트에서의 반사계수 특성을 향상시키기 위해서 측면포트에 얇은 격막을 삽입하였다. 전체적인 설계에 상용소프트웨어인 HFSS$^{R}$를 사용하였다.

• 한국가스학회지
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• 제13권6호
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• pp.1-8
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• 2009

본 연구는 웻지 시스템을 이용하여 3축 방향의 진동 및 충격을 완화시킬 수 있는 감쇠기에 관한 것이다. 기존의 수직방향 진동/충격에 대해서만 흡진하는 디스크 스프링 완충기를 개선하여 웻지를 추가함으로써 종 방향은 물론 횡 방향을 모두 포함한 3축에 대해 흡진이 가능한 댐퍼를 제안하였다. 수학적 모델을 수립하여, 댐퍼내의 중요한 요소로 작동하는 디스크 스프링과 웻지의 특성을 고찰하였으며, 실험을 통해 댐퍼의 거동을 고찰하였다. 수치 해석 결과와 실험 결과가 잘 일치함을 알 수 있었고, 소산된 에너지양을 구한 후, 수직 수평방향에 대한 등가 점성 감쇠를 구하였다.

• 대한공간정보학회지
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• 제12권3호
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• pp.51-59
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• 2004

포장노면관리시스템은 노면의 상태를 정밀히 조사 분석하고 유지보수에 대한 계획을 수립할 수 있는 시스템으로 구성하여야 한다. 현재 구축되어 있는 대부분의 포장노면관리시스템은 전문가가 현장에서 노면의 상태를 조사한 후 그 결과를 입력하도록 되어있다. 현재의 실정과 향후의 포장도로의 증가를 고려할 때 포장도로 전체를 전문가가 직접 조사하는 것은 비효율적 일 뿐만 아니라 지속적인 포장노면관리시스템의 유지가 어려운 실정이다. 따라서, 다중영상표정과 광속조정법에 의해 결정된 도로노면의 3차원 좌표의 정확도를 분석한 결과 표준오차의 평균은 X방향으로 0.0427m, Y방향으로 0.0527m, Z방향으로 0.1539m로 나타났다. 이 결과는 우리나라에서 현재 제작하여 사용하고 있는 축척 1:1000 이하의 지도제작 및 GIS 자료로서 충분히 활용성이 있다.

• 전자공학회논문지SC
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• 제47권5호
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• pp.52-61
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• 2010

최근 피부의 마찰계수를 이용하여 한의학에서의 체질을 구별하는 연구가 활발히 이루어지고 있다. 피부의 마찰계수는 여러 고문헌에서도 알려져 있듯이 태음인과 소양인의 체질을 구별하는 인자로 활용되고 있다. 본 연구에서는 다축 로드셀과 일정하중식 접촉 프로브를 이용하여 피부의 마찰계수를 정량적으로 측정하는 장비를 개발하였고 이의 측정 불확도를 측정하였다. 개발된 장비의 상대 반복도는 2 %였다. 태음인과 소양인의 체질진단 구분을 위해 왼속 손등을 측정부위로 선택하여 실험한 결과 약지를 따라 측정하는 것이 가장 효과적임을 알 수 있었다. 20명의 피험자를 대상으로 임상측정을 한 결과, 개발된 장비의 경우 3 % 이내의 측정 불확도를 가지고 태음인과 소양인의 체질 구분을 할 수 있었다.

• 한국정밀공학회지
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• 제17권10호
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• pp.83-88
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• 2000

multi-beam optical drive is a method to improve the data transfer rate for the optical disc systems by parallel recording and reading on neighboring multi-tracks. In this paper, the beam rotating actuator, which is necessary for the multi-bean optical disc drive to from beam spots on multi-tracks simultaneously, has been developed. The Voice Coil Motor is used as a drive mechanism for high resolution and small size of the actuator. And rotating guide based on link structure is designed for frictionless and axisless rotation of rotating part including dove prism and for rotating in axis of geometric center of dove prism. The characteristics of the actuator are experimented by laser vibrometer, Polytec OFV1102 and a dynamic analyzer, HP35670A. It shows that the actuator has good linearity, rotating range $\pm0.34^\circ$, minimum rotating angle $0.0066^\circ$and natural frequency 113.9Hz. Therefore the actuator can be applied in a multi-beam optical disc system.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.725-730
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• 2007

A framework of multi layered database is proposed for the integrated operation of civil infrastructure information in this study. The multi-layered database is a logically integrated database composed of standardized information layers. The framework of multi-layered database is defined by three axes, national assets, lifetime, and data levels. The axis of national assets indicates civil infrastructures such as bridges, dams, tunnels and power plants that can be considered as national key structures. The axes of lifetime and data levels indicate the standardized information layers generated from the life-phase of civil infrastructure and the priority of data in the information layers, respectively. The standardized information layers are basically composed of reusable data sets defined by information models. A prototype of standard database for steel bridges is constructed based on the framework as a proof of concept. Demonstration examples such as data consistency check and automatic generation of a FEA model show that the proposed concept can assure the sustainable interoperability of civil infrastructure information as well as design information of steel bridges.