• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.579-587
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• 1999

The flow distribution characteristics in a complex duct system have been investigated in this paper by three means, namely experimental measurement, numerical simulation and the Extended T-method analysis. While the exit flow rates predicted by the three-dimensional CFD calculation and those given by the experiment show a close agreement, the results from the one-dimensional Extended T-method are found to differ from the experiment by -22.2% to 26.3% for the various exits. These discrepancies may be attributed to the underlying limitation concerning the fitting loss coefficients, which assume that the flow in front of the fittings is fully developed. It is proposed that, in order to analyse the three-dimensional flow distributions in a complex duct system by one-dimensional analysis such as the Extended T-method, further Improvements to the fitting loss coefficients should be made.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.39-45
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• 1997

Shadow moire topography has been used as a noncontact method for measuring the 3-D shapes of objects. The moire fringes are results from the superposition of a master grating and its shadow projected on the surface of an object. But in case of the classical shadow moire method, in general, the resolution is a few tenths of millimeter. It is difficult to use a phase -shifting method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study , We introduce a phase-shifting method to improve the resolution of the classical shadow moire method. This method is based on the fact that if the depth of object is much less than the distance between the observer and the master grating, the phase shifts are almost uniform on the whole field area. Finally, we applied this new phase-shifting method to the measurement of the 3-D shape of a coin.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.85-89
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• 1997

We used a three-dimensional motion capture method to measure the grasping reach of Korean. This method was applied well to the grasping reach measurement with low measurement error and high efficiency. We measured the grasping reach of 29 males and 21 females at the different height from seat reference level; -10, 0, 30, 60, and 90cm. The grasping reach data were summarized at each 15 .deg. in polar corrdinates to compare with the former researches. If the number of subjects increases in the supplement research, the grasping reach data will be used in the ergonomic design of the driver's cabin or workstations in industry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.96-100
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• 1997

The shadow moire is one of the optical techniques which is able to give contour lines of an object with respect to a master grating plane. The moire patterns are issued from the superposition of a master grating and its shadow projected on the surface of an object. In case of the classical shadow moire method, the sensitivity was a few tenths millimeters. generally, it is difficult to use a phase shift method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study we use the fact that if the depth of object is much less than the distance between the observer and the master grating, and the object is displaced perpendicularly to the grating plane, phase shifts are almost uniform. Finally we obtained a better resolution by using a phase shift procedure and applied the phase shifting shadow moire to three dimensional shape measurement.

• 한국가시화정보학회:학술대회논문집
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• 2006.12a
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• pp.73-77
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• 2006

Flow rate measurement is one of the difficult problems in the industrial applications. Especially, flow rate in a partially filled pipeline is affected by many parameters such as water level, channel slop, etc. In the present study, prior to the development of a flowmeter, the flow characteristics has been investigated by particle image velocimetry (PIV) measurements. Three-dimensional velocity distributions were obtained from sectional measurements of velocity profiles according to the water level. As a result, it is found that there is no similarity in the velocity profile when the lateral position is changed. In addition, the maximum velocity does not always occur on the free surface. It depends on the water level. In the aspect of flow rate measurement, the previous calculus based upon point measurement techniques is proved to be inaccurate because of the lack of whole flow information.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.727-731
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• 2005

We introduce a method of color-coded illumination that is simple and fast. The purpose of this study is the real-time shape measurement of three-dimensional object by using color-coded information. The object is illuminated by a prism color spectrum. A color spectrum of a white-light source is imaged onto the object by illumination from one certain direction. The object is observed by a color CCD camera from a direction of observation, which is different from the direction of illumination. It can be evaluated by the red, blue, green using a inherence colors of hue value are good point.

• Journal of Multimedia Information System
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• v.5 no.2
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• pp.115-120
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• 2018

Recently, ways for accurately measuring the three dimensional movements of hand are actively researched so as to utilize the measurement data for therapeutic and rehabilitation programs. This research paper aims to introduce a product called Myo Armband, a wearable device comprised of a 3-axis accelerometer, a 3 axis gyroscope, and electromyographic sensors. We compare Armband's performance with that of the Motion Capture System, which is known as a device for providing fairly accurate measurements for angular movements of objects. Dart throwing and wrist winding motions comprised movement scenarios. This paper also discusses one of Armband's advantages - portability, and suggests its potential as a substitute for previously used devices. Decent levels of measurement accuracy were obtained which were comparable to that of three dimensional measurement device.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.38-45
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• 1996

The optical triangulation method has been used as a non-contact measuring method of three dimensional object whape. But this measuring method has narrow measuring range, non-linearity on steep slope surface and shadow effect. In this study, we discussed a new optical measurement method to overcome these kinds of demerits. The advantage of this new method is that it is possible to measure precisely the object shape having the steep slope surface without shadow effect. As exper- imental results, maximum displacement error was 200 .mu. m over the whole measuring when the incident angle on the object surface was within 60 degree.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.531-537
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• 2014

Through-silicon vias (TSVs) are fine, deep holes fabricated for connecting vertically stacked wafers during three-dimensional packaging of semiconductors. Measurement of the TSV geometry is very important because TSVs that are not manufactured as designed can cause many problems, and measuring the critical dimension (CD) of TSVs becomes more and more important, along with depth measurement. Applying white-light scanning interferometry to TSV measurement, especially the bottom CD measurement, is difficult due to the attenuation of light around the edge of the bottom of the hole when using a low numerical aperture. In this paper we propose and demonstrate four bottom CD measurement methods for TSVs: the cross section method, profile analysis method, tomographic image analysis method, and the two-dimensional Gaussian fitting method. To verify and demonstrate these methods, a practical TSV sample with a high aspect ratio of 11.2 is prepared and tested. The results from the proposed measurement methods using white-light scanning interferometry are compared to results from scanning electron microscope (SEM) measurements. The accuracy is highest for the cross section method, with an error of 3.5%, while a relative repeatability of 3.2% is achieved by the two-dimensional Gaussian fitting method.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.152-159
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• 2014

Recently. utilization of remote sensing exploration and cloud computing has been extended to efficient measurement, store, and update of bathymetry map data according to cloud computing technology. In the field of real ocean, water depth measurements and measurement data management, distribution, and display equipment for the development and dissemination have generated a lot of time and cost. To improve these problems, through real-time three-dimensional display system at this location, we can determine the importance of measurement activities, and reduce the time and cost of measurement activities. Data measured from marine probe vessels and remote sensing exploration equipments and other various channels can be handled and managed. In this paper, we propose a realtime three-dimensional display system through the depth measurements from remote sensing exploration. The proposed real-time three-dimensional display system can be effectively applied in the field of measurement of the topographical survey of the land as well as bathymetry of the sea.