• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.249-250
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• 2002

In this paper, the relationship among the 3-D surface topography parameters are studied. Several surface topography parameters that are important in tribology are calculated against various surface topography data. 3-D surface data with desired properties are generated by using the non-causal 2-D auto-regressive (AR) model. The non-causal 2-D AR model is a random 3-D surface topography model that can generate 3-D surface topography data with specified parameters.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.3 no.1
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• pp.61-70
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• 2005

The purpose of study correlation between 3D-surface topography and Cobb angle in scoliotic patients. It would be recognizing possibility of clinical application with 3D-surface topography with scoliosis assessment and correlation analysis of obtained Cobb angle through measured results of surface topography and took X-ray of subjects with scoliosis, which used to 3D-surface topography of laser scan method. A scoliosis subjects 16(males 4, females 12) agreed for study's purport volunteer our study that diagnose the scoliosis through 3D-surface topography and X-ray. The results were as follow: It was shown that the relation of Cobb angle of scoliosis and itemized 3D-surface topography measurement in horizontal view(p<0.01). top difference of cervicothoracic and lumbar in anterior-posterior view(p<0.05), the top difference of thoracic, thoracolumbar(p<0.01). These results suggest that an itemized 3D-surface topography measurement was highly correlated with Cobb angle. It would be a useful diagnosis method and assessment of physical therapy plan.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.2 no.3
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• pp.51-64
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• 2004

This study understood measured items of significantly difference through the surface topographical comparison of dorsal trunk's surface between normal and scoliosis subjects. 300 subjects for this study were participated (middle, high school and college students). Normal 28(males 12, females 16) and scoliosis subjects 16(males 4, females 12) were chosen by assessment tools (physical examination, 3D-surface topography) among subjects at Dongshin University Oriental Hospital. The results were as follow: 1. It was shown that the significantly difference was observed by distance of peak to curve with scoliosis between two groups(p<0.001). 2. It was shown that top difference of between groups in anterior-posterior view was the significantly difference at cervicothoracic, thoracic, thoracolumbar and dorsal part of lumbar(p<0.001). These results suggest that method to use 3D-surface topography measurement would be useful diagnosis method and clinical use of physical therapy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.496-504
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• 2006

Wear of engine valves and seat inserts is a major factor affecting engine performance. In order to improve quality and life of valve assemblies, wear mechanism and 3-D surface topography should be analyzed according to operating conditions of the engine. After developing an engine simulator that generates valve speed up to 90Hz and temperature up to $900^{\circ}C$ as well as controls test load, wear experiments have been conducted for two different engine speeds as 10Hz and 25Hz. In order to observe the wear characteristics and monitor surface conditions of the valve assemblies, a cost-effective 3-D wear analysis system based on the shape from focus(SFF) and machine vision has been fabricated in this paper. 3-D surface topography of the valve assemblies has been analyzed to understand the wear behavior according to operating conditions of the engine. Consequently, wear volume of the valve assemblies is quantized by using the developed 3-D wear analysis system.

• Journal of the Korean Ceramic Society
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• v.31 no.3
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• pp.249-256
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• 1994

By surface structure and X-ray topographic observation, growth mechanism of NAB single crystal grown by TSSG technique using a BaB4O7 flux was studied. Surface structure of grown crystals were investigated by optical microscope. Growth history and crystal defects included within grown crystal were investigated using X-ray topography. The {001} faces were grown by 2-D nucleation growth. As decreasing cooling rate, growth mechanism of {111} and {11} was changed from 2-D nucleation growth to the growth by screw dislocation. Only surface striations developed parallel to a-axis were observed on {010} faces. Growth sector of NAB crystals were divided into {001}, {111}, {010}, {021}, {11}. The inclusion which was usually trapped between {001} faces was investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.292-295
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• 2003

Moire topography method is a well-known non-contacting 3-D measurement method. the automatic 3-D measurement by moire topography has been required since the method was frequently applied to the engineering and medical fields. 3-D measurement using digital projection moire topography is very attractive because of its high measuring speed and high sensitivity. In this study, digital two-wavelength phase shilling moire is applied to the entertainment fields. recently. as promoting the growth of the VR-Game, display devices which attract public attention such as HMD or Projector are being appeared in order to deliver effectively the absorption sense. this study realized the Auto-calibrating system for arbitrary display surface using digital moire method which satisfied the shape measurement of display surface and the request of FOV(Field of View) output. also when large screen wasn't prepared, this auto-calibrating system was applied to enjoy games or movies at home with a projector and walls

• Tribology and Lubricants
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• v.40 no.2
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• pp.47-53
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• 2024

Surface topography plays a decisive role in determining the performance of several precision components. In particular, the surface roughness of semiconductor devices affects the precision of the circuit. In this regard, the surface topography of a given surface needs to be appropriately assessed. Typically, the average roughness is used as one of the main indicators of surface finish quality because it is influenced by both dynamic and static parameters. Owing to the increasing demand for such accurate and reliable surface measurement systems, studies are continuously being conducted to understand the parameters of surface roughness and measure the average roughness with high reliability. However, the differences in the measurement methods of surface roughness are not clearly understood. Hence, in this study, the surface roughness of the back of a silicon wafer was measured using both contact and noncontact methods. Subsequently, a comparative analysis was conducted according to various surface roughness parameters to identify the differences in surface roughness depending on the measurement method. When using a 3D laser confocal microscope, even smaller surface asperities can be measured compared with the use of a 3D profiler. The results are expected to improve the understanding of the surface roughness characteristics of precision components and be used as a useful guideline for selecting the measurement method for surface topography assessment.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.235-236
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• 2002

Tribological phenomena such as wear or transfer are influenced by various factors and have complicated behavior. Therefore, it is difficult to predict the behavior of the gribological phenomena because of their complexity. But, those tribological phenomena can be considered simply as to transfer micro material particles from the sliding interface. Then, we proposed the numerical simulation method for tribological phenomena such as wear of transfer using stochastic process models. This numerical simulation shows the change of the 3-D surface topography. In this numerical simulation, initial 3-D surface toughness data are generated by the method of non-causal 2-D AR (autoregressive) model. Processes of wear and transfer for some generated initial 3-D surface data are simulated. Simulation results show successfully the change of the 3-D surface topography.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.275-284
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• 2007

For precise interpretation of magnetotelluric (MT) data distorted by irregular surface terrain, topography effects are investigated by computing apparent resistivities, phases, tippers and induction vectors for a three-dimensional (3D) hill-and-valley model. To compute MT responses for the 3D surface topography model, we use a 3D MT modeling algorithm based on an edge finite-element method which is free from vector parasites. Distortions on the apparent resistivity and phase are mainly caused by distorted currents that flow along surface topography. The distribution of tipper amplitudes over both hill and valley are the same, while the tipper points toward the center of hill and the base of the valley. The real part of induction vector also points in the same direction as that of tipper, while the imaginary part in the opposite direction.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.2
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• pp.25-32
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• 1998

In this paper, we report the result of the three-dimensional topography simultor, 3D-SURFILER(SURface proFILER) for the simulation of topographical evalution of the surface, curing a plasma etching process. We employed cell-removal algorithm to represent the topographical evoluation of the surface. The visibility with shadow effect was developed and applied to the spillover algorithm. To demonstrate the capability of 3D-SURFILER, we compared with simulated profiles with the SEM picture for dry and reactive ion etching(RIE) of the Si$_{3}$N$_{4}$ film and Pt film.