• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.173-176
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• 2006

The purpose of this study is to investigate the cause of an error of prefounded column straightness and to measure the error during Top-Down construction. There are several causes of an error of prefounded column : (1) The columns are connected by welding or other methods. (2) concrete and aggregates are put in columns. (3) The columns are constructed during the construction. The error of column straightness is different for each column, and the tilting of columns is shown in one or two directions between floors. The additional loads caused by the error of straightness may give damage to buildings.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.1
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• pp.17-21
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• 2019

In this paper, a high precision straightness measurement system has been developed at low cost using a visible laser and CMOS image sensor. CMOS image sensor detected optical image and the variation of straightness was calculated by image processing. We have observed that the error of the developed straightness measurement system was 0.9% when a distance of 3m between laser and image sensor. And it can be applied to 3D printer and any other areas.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.607-614
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• 2013

In this study, effect of the sensor gain error is theoretically analyzed and simulated when mixed sequential two-prove method(MTPM) is applied for the precision measurement of straightness error of a linear motion table. According to the theoretical analysis, difference of the gain errors between two displacement sensors increases measurement error dramatically and alignment error of the straightedge is also amplified by the sensor gain difference. On the other hand, if the gain errors of the two sensors are identical, most of error terms are cancelled out and the alignment error doesn't give any influence on the measurement error. Also the measurement error of the straightness error is minimized compared with that of the straightedge's form error owing to close relationship between straightness error and angular motion error of the table in the error terms.

• Agricultural and Biosystems Engineering
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• v.1 no.2
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• pp.100-105
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• 2000

Quality sorting of cut flowers is very essential to increase the value of products. There are many factors that determine the quality of cut flowers such as length, thickness, and straightness of stem, and color and maturity of bud. Among these factors, the straightness of stem and the maturity of bud are generally considered to be more difficult to evaluate. A prototype grading and sorting machine for cut flowers was developed and tested for a rose variety. The machine consisted of a chain-drive feed mechanism, a pneumatic discharge system, and a grading system utilizing color image processing and neural network. Artificial neural network algorithm was utilized to grade cut roses based on the straightness of stem and maturity of bud. Test results showed 89% agreement with human expert for the straightness of stem and 90% agreement for the maturity of bud. Average processing time for evaluating straightness of the stem and maturity of the bud were 1.01 and 0.44 second, respectively. Application of neural network eliminated difficulties in determining criteria of each grade category while maintaining similar level of classification error.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.88.3-88
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• 2001

In this paper, an on-line multi-sensor visual inspection technique for seamless steel pipe´s straightness is developed. The basic principle of the visual measuring method is detailed. The modeling of visual sensor, measurement system and data processing are presented. In order to test the accuracy of the multi-sensor visual inspection, an experiment inspecting the straightness of a 1500mm long seamless steel pipe is made. The experiment results show that the visual inspection technique can achieve on-line measurement and offers high precision and stability.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.11-14
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• 2007

An additive servo-system is developed to improve straightness of linear motor stages. For linear motor stages used in the field of high-precision linear motion process, high straightness accuracy is necessary as well as positioning accuracy in the longitudinal axis. In such cases, machining and assembling cost increases to improve the straightness accuracy. An electro-magnetic actuator which is relatively cost effective than any other conventional servo-systems is suggested to compensate the fixed straightness error. To overcome the compensation error due to modeling error and friction disturbance, a sliding mode control is addressed. The effectiveness of the suggested mechanism and the control are illustrated along with some experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.203-206
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• 2001

This paper presents a straightness measurement system for flat and long workpieces. The measurement system consists of a laser optical unit, a CCD camera and processing system, and a carrier system with a stylus. The carrier system accompanies the stylus, which displaces a retroreflector along the surface profile. The optical unit is used to optically amplify the displacement of retroreflector. The CCD camera and processing system finally identifies the vertical displacement of the stylus unit. The developed system is applied to two surfaces: ground surface and LM guide surface. The experimental results show that the developed system can measure the straightness of flat surfaces within sub-micron error.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.10 s.181
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• pp.2451-2460
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• 2000

In order to minimize straightness error of deflected shaft, a geometric adaptive straightness controller system is studied. A multi-step straightening and a three-point bending process have been developed for the geometric adaptive straightness controller. Load-deflection relationship, on-line identification of variations of material properties, on-line springback prediction, and real-time hydraulic control methodology are studied for the three-point bending process. By deflection pattern analysis and fuzzy self-learning method in the multi-step straightening process, a straightening point and direction, desired permanent deflection and supporting condition are determined. An automatic straightening machine has been fabricated for rack bars by using the developed ideas. Validity of the proposed system is verified through experiments.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.107-113
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• 2002

This paper presents a straightness measurement system for flat and long workpieces. The measurement system consists of a laser, a CCD camera and processing system, a carrier system with a stylus, and some optical units. The carrier system accompanies the stylus, which displaces and retroreflector along the surface profile. The optical unit is used to optically amplify displacement of the stylus unit. The developed system is applied to a ground surface and a LM guide unit. The experimental results show that the developed system can measure the straightness of flat surface and moving systems.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.170-177
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• 2000

Sorting cut roses according to quality is very essential to increase the value of the product. Many factors are involved in determining the grade of cut roses: length, thickness, and straightness of stem, color and maturity of bud, and extra. Among these factors, the stem straightness and bud maturity are considered to be difficult to set proper classification criteria. In this study, a prototype machine and an analysis procedure were developed to grade cut roses according to stem straightness and bud maturity by utilizing color image processing and neural network. The test results indicated 15.8% classification error for stem straightness and 10.0% for bud maturity.