• Proceedings of the KSME Conference
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• 2001.06e
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• pp.714-719
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• 2001

The Holographic Particle Velocimetry system can be a promising optical tool for the measurements of three dimensional particle velocities. In this research, the optical system for double pulse holographic recording and reconstruction of particle images was developed. Validation experiments for the developed system were conducted measuring the velocities of glass beads on a rotating disk. Uncertainty analysis was performed to identify the sources of all relevant errors and to evaluate their magnitude. The measurement results of distance between glass beads, size, and velocities of them using holographic method compared reasonalbly well with the known values within acceptable range of errors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.195-198
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• 2002

Demand for high precision measurement of large area is increasing in many industrial fields. White-light Scanning Interferometer(WSI) is a well-known method for 3D profile measurement. However WSI has some limitations in a measurement range because of the sensing mechanism. Therefore, in this paper we use a heterodyne laser interferometer to get over the limitations of a short measurement range in WSI, We suggest a new WSI system combined with heterodyne laser interferometer. This system is aimed at eliminating Abbe error with measuring the focus point directly. With the use of triggering functionality of WSI, we can use this system as a probe of a precision stage such as a probe of CMM. The suggested system gives a repeatability of 87 nm in the absolute distance measurement test under the laboratory environment.

• Journal of Korean Society for Quality Management
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• v.30 no.3
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• pp.111-119
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• 2002

Gears are essential elements for mechanical power transmission. Geometric precision is the main factor for characterizing gear grade and qualify. Gear pitch is one of the crucial measurements, which is defined as a distance between two adjacent gear teeth. It is well-known that variability in gear pitches may causes wear-out and vibration noise. Therefore maintaining pitch errors at a low level plays a key role in assuring the gear quality to customers. This paper is concerned with a case study, which presents a computerized system for Inspecting pitch errors in a gear machining process. This system consists of a PC and window-based programs. Although the start and stop is manually accomplished, the process of measuring and analyzing pitch data is automatically conducted in this system. Our purpose lies in reducing inspection cost and time as well as Increasing test reliability. Its operation is briefly illustrated by example. Sometimes a strong autocorrelation is observed from pitch data. We also discuss a process monitoring scheme taking account of autocorrelations.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.1
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• pp.103-109
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• 2015

This paper introduces a multi-purpose smart fusion sensor. Normally, this type of sensor can contribute to energy savings specifically related to lighting and heating/air conditioning systems by detecting individuals in an office building. If a fire occurs, the sensor can provide information regarding the presence and location of residents in the building to a management center. The system consists of four sensors: a thermopile sensor for detecting heat energy, an ultrasonic sensor for measuring the distance of objects from the sensor, a fire detection sensor, and a passive infrared sensor for detecting temperature change. The system has a wireless communication module to provide the management center with control information for lighting and heating/air conditioning systems. We have also demonstrated the usefulness of the proposed system by applying it to a real environment.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.590-595
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• 2000

On the contrary to the increasing needs of shape qualities, most of quality inspections are carried out by manual or operator's insight. To find the causes of shape inferiority, it is required to gather and analyze the shape measurement data. As a result the winding profile measurement system ($TELE-SCANNER^{(R)}$) is developed to analyze the coiling process and automate the manual measuring process for winding profile of hot-rolled coils. The winding profile measurement system measures and analyzes winding profile shapes of hot-rolled coils, and classifies them into several dominant patterns that are related to normal or abnormal mechanical conditions of down-coiler. The system also contains analysis software to quantify the winding profile shapes and patterns, and to produce statistics to help search the causes of profile shape inferiority.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.04a
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• pp.225-228
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• 2005

본 논문에서는 이동로봇의 저가형 위치인식센서로 적합한 PSD(Position Sensitive Detector)센서를 이용하여 거리계측시스템을 개발하였다. PSD 센서는 거리-전압 출력이 비선형적인 단점을 가지고 있어 센서의 특성실험을 통해 선형화가 가능한 변환함수를 제안하였다. 제안한 방법을 검증하기 위하여 거리계측시스템의 하드웨어 및 소프트웨어를 구성하였다. 또 피측정체의 색상 및 재질에 따른 출력특성을 실험하고 거리-전압 데이터를 측정하였다. 실측한 데이터를 바탕으로 제안한 선형화함수의 계수를 추출하였다. 마지막으로 제안한 함수에 의한 거리와 실제거리를 비교하여 시스템의 성능 및 정확성을 검증하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.49-52
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• 2011

This study concerned with the retention structures or inverted temporary building for displacement measurement in the underground soil after drilling a vertical tilt sensor attached to the vertical distance required to maintain a real-time measurement and management in order to install the wireless measuring devices installed in the field through remote control and management program for the safety of retaining structures temporary building be found on the internet in real time temporary building the retention is to develop a safety management system. And based on this technology to monitor the future status of the various structures possible to add a variety of sensors and Life Cycle Prediction of the structure and needs to evolve into intelligent systems and wireless networks using wireless communications infrastructure systems based on expanding domestic market penetration by developing instrumentation pioneer in overseas markets as well as the activation can also be judged.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1647-1652
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• 2008

Track geometry consists of tangent and curved lines, which caused undesirable changes in initial track geometry by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To be able to objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies use moving chord method, this method determine versine values via a chord. The versine is the vertical distance to curve measured in the middle of the chord. This type of method measures only versine of track irregularity curve by transfer function from specific property of measuring tool. In this report, review the characteristics of two types of measuring tools by comparing the measurements. The one is GRP-1000 system, optical surveying system with Total station and lazar prism trolly. This calculates track geometry by surveying absolute coordinates of two points each on both rail heads. The other is Trackmaster, measures versine with 2m of chord length.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.199-205
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• 2015

Indoor positioning technology has been developed very actively for the smart phone handheld by most users. Especially, many TDOA positioning systems using acoustic signal have been studied, and it estimates the smart phone position by measuring the distance between the smart phone speaker and the microphones which is installed to receive the acoustic signal from the smart phone, and by calculating the hyperbolic equations. But there are always errors for the distance measurements, and furthermore the microphone installation error produces huge position estimation error. In this paper, the position estimation error due to the position error of acoustic sensor in the 3 dimensional TDOA positioning system, is analyzed by PDOP simulation and experiment.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.493-504
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• 2007

This paper proposes a stereo vision-based forward obstacle detection and distance measurement method. In general, stereo vision-based obstacle detection methods in automotive applications can be classified into two categories: IPM (Inverse Perspective Mapping)-based and disparity histogram-based. The existing disparity histogram-based method was developed for stop-and-go applications. The proposed method extends the scope of the disparity histogram-based method to highway applications by 1) replacing the fixed rectangular ROI (Region Of Interest) with the traveling lane-based ROI, and 2) replacing the peak detection with a constant threshold with peak detection using the threshold-line and peakness evaluation. In order to increase the true positive rate while decreasing the false positive rate, multiple candidate peaks were generated and then verified by the edge feature correlation method. By testing the proposed method with images captured on the highway, it was shown that the proposed method was able to overcome problems in previous implementations while being applied successfully to highway collision warning/avoidance conditions, In addition, comparisons with laser radar showed that vision sensors with a wider FOV (Field Of View) provided faster responses to cutting-in vehicles. Finally, we integrated the proposed method into a longitudinal collision avoidance system. Experimental results showed that activated braking by risk assessment using the state of the ego-vehicle and measuring the distance to upcoming obstacles could successfully prevent collisions.