• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.259-266
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• 2022

In this study, we developed a deep learning and vision sensor-based assembly performance evaluation method isfor prefabricated steel structures. The assembly parts were segmented using a modified version of the receptive field block convolution module inspired by the eccentric function of the human visual system. The quality of the assembly was evaluated by detecting the bolt holes in the segmented assembly part and calculating the bolt hole positions. To validate the performance of the evaluation, models of standard and defective assembly parts were produced using a 3D printer. The assembly part segmentation network was trained based on the 3D model images captured from a vision sensor. The sbolt hole positions in the segmented assembly image were calculated using image processing techniques, and the assembly performance evaluation using the k-nearest neighbor algorithm was verified. The experimental results show that the assembly parts were segmented with high precision, and the assembly performance based on the positions of the bolt holes in the detected assembly part was evaluated with a classification error of less than 5%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.274-274
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• 2004

조향성능은 완성된 자동차를 평가하는 아주 중요한 요소이며, 운전자에게 직접적인 영향을 가지는 까닭으로 우선적으로 해결되어야 할 문제이다. 자동차의 조향성능과 관련된 자동차 요소로는 프런트 샤시 모듈이 있으며, 프런트 샤시 모듈의 자세는 구성 요소인 서브프레임의 조립자세에 의하여 결정된다. 서브프레임은 4개의 원통형 지지부로 이루어져 있으며, 차체와의 조립시 지지부에 물리적 접촉이 발생한다. 즉 공간상에서 서브프레임의 자세는 지지부의 조립위치에 의하여 결정이 되며, 서브프레임의 자세를 결정하기 위해서는 지지부에 대한 적절한 해석이 필요하다.(중략)

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.173-178
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• 2024

This study presents a technique for assessing the dimensional quality of assembly parts in Prefabricated Steel Structures (PSS) using a stereo vision sensor. The stereo vision system captures images and point cloud data of the assembly area, followed by applying image processing algorithms such as fuzzy-based edge detection and Hough transform-based circular bolt hole detection to identify bolt hole locations. The 3D center positions of each bolt hole are determined by correlating 3D real-world position information from depth images with the extracted bolt hole positions. Principal Component Analysis (PCA) is then employed to calculate coordinate axes for precise measurement of distances between bolt holes, even when the sensor and structure orientations differ. Bolt holes are sorted based on their 2D positions, and the distances between sorted bolt holes are calculated to assess the assembly part's dimensional quality. Comparison with actual drawing data confirms measurement accuracy with an absolute error of 1mm and a relative error within 4% based on median criteria.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.431-439
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• 2014

Concrete filled tubular columns are widely used because the mutual reaction between the concrete and the tube improves strength and ductility of the columns. In an attempt to secure efficient use of members, built-up square columns featuring large width-thickness ratio and the use of thin steel plates are suggested in this study. In order to evaluate the structural characteristics and seismic performance of the column-to-beam connections of the new shape columns, cyclic load test of T-shaped column-to-beam connections was conducted with variables of diaphragms and concrete-filling. Moment-rotational angle relationship, dissipated energy and failure behavior were compared to evaluate stress transfer mechanism of the new shape built-up square column-to-beam connections associated with the variables.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.517-520
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• 2017

In this paper, we represented the structural design parameter effect on the sealing gap behavior of solid rocket motor case and nozzle connection under penetrated pressure through the sealing path between insulation rubber and the ablative FRP bonded on the inside convergent wall of nozzle. It is important to keep the good sealing capacity during all the combustion time of SRM. To achieve the crucial role of sealing system of SRM, designers must consider design factors for stable sealing clearance gap as the nearly unchanged initial design state as possible for sufficient compression rate of O-ring under sealing gap pressure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.956-959
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• 2007

기존 투명방음판용 알루미늄 프레임의 구조적 단점을 보완할 수 있는 강재-FRP(Fiber Reinforced Plastic) 합성단면 구조재를 개발하였으며, 아울러 조립이 간편하고 외부 충격에 의해 쉽게 분리가 되지 않는 삽입형 수평재-수직재 코너연결부 상세를 개발하였다. 개발된 강재-FRP 합성단면 구조재와 코너연결재를 결합하여 프레임을 형성하고 그 사이에 투명패널을 삽입함으로써 길이 4m, 높이 1m 투명방음판 시작품을 완성하였으며, 이렇게 완성된 투명방음판 시작품을 대상으로 KS 4770-1 구조성능 평가시험을 수행하였다. 한국도로공사 교량부 시험하중에 대해 설계된 강재-FRP 합성단면 프레임 투명방음판의 구조성능 평가결과, FRP 의 추가적인 구조강성 증가 효과로 인해 한국도로공사 교량부 시험하중을 약간 상회하는 KS 2 호 등급시험하중까지도 만족시키고 있음을 확인할 수 있었다.

• Electronics and Telecommunications Trends
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• v.8 no.3
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• pp.1-10
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• 1993

제어 신호용 SAR 부계층 기능부는 메시지 단위로 통신을 수행하는 프로세서와 셀 단위로 전송이 이루어지는 ATM 스위치망간의 정합을 수행한다. 이 기능부는 메시지를 셀로 분할하는 분할부와 셀을 메시지로 조립하는 재결합부로 구성되어 있다. 각종 제어와 관련된 신호의 SAR 기능을 실행하는 이 부분에서 발생하는 병목현상은 전체 교환시스팀의 성능에 미치는 영향이 크다. 본 연구에서는 제어 신호용 SAR 부계층 기능부에 대한 성능 평가 모델을 제시하고 재결합부에 대한 성능 분석을 수치계산 예를 들어 설명한다.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.43-48
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• 2008

The object of this paper is to evaluate on constructability of modular steel frame with the hollow structural steel section to LEB C-shape. A modular building is built with factory-manufacture and site-construction. The advantage of a Modular building presents that enhanced building quality, shortened construction period and easy at an expansion and enlargement for buildings but also has demerits such as size restriction of the modular units according to the Road Traffic Law and Inflexibility of the unit composition. So in this study we use light-weighted structure members with bolted joint for easy Knock-down and traffic, also we evaluated the constructability of this bolted joints type modular buildings.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.807-815
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• 2008

The brittle failure where is occurred the welding position of column-beam flange of WUF-B connection that consider about a seismic detail possess a superior ductility capacity before Northridge earthquake 1994, require newly study about WUF-B connection. SAC Steel Project suggests a seismic detail to FEMA-350 by supporting of FEMA. It revise shape of weld access holes of WUF-B connection, welding processand welding material etc, In spite of these revision, AISC Seismic Provisions (2005) prescribe WUF-B connection using an only OMF. Recently in Korea, as the earthquake of about seismic intensity 5 occur, the necessity of revision for connection seismic detail comes to the front in Korea and FEMA-350 connection seismic details are going to include in KBC-2008 as it is. In this study, two column-beam connection specimens were marked by using SM490, SN490 built-up H-section, and based on WUF-B detail prescription of FEMA350. The parameters of the specimens are types of steel (SM, SN), and evaluate the capacities of structure and seismic by experiment. Finally we confirm a superior ductility capacity aboutspecimens JB-1 and JB-2, using SM490 and SN490,and these specimens had sufficient OMF and SMF seismic capacity, as indicated in AISC Seismic Provisions (2005).

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.711-722
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• 2008

Existing tube for concrete filled tubular structure is made through welding of four plates irrespective of tube thickness, so production performance is poor and special welding technique is needed to weld the internal diaphragm and through the diaphragm. Therefore, through manufacturing by cold forming development of beam to column connections that is no welding in position of stress concentration is needed. In this study the proposal of beam to column connections details and to making tube specimens by method of bending steel plates, we want to know the compositeeffect between internal anchor and concrete by processing on stress distribution and internal force evaluation of concrete filled tube beam to column connections with a variable of flange welding existence between column and beam, welding quantity between column and diaphragm, existence of concrete in tube, column with diaphragm and general column.