• Journal of Multimedia Information System
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• v.2 no.3
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• pp.255-262
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• 2015

The modern manufacturing systems and technologies produce products that are more accurate day by day. This can be reached mainly by improvement the manufacturing process with at the same time restricting more and more the quality specifications and reducing the uncertainty in part. The main objective an industry becomes to lower the part's variability, since the less variability - the better is product. One of the part of this task is measuring the object's uncertainty. The main purpose of this study is to understand the application of bootstrap method for uncertainty evaluation. Bootstrap method is a collection of sample re-use techniques designed to estimate standard errors and confidence intervals. In the case study a surface of an automobile engine block - (Top view side) is measured by Coordinate Measuring Machine (CMM) and analyzed for uncertainty using Geometric Least Squares in complex with bootstrap method. The designed experiment is composed by three similar measurements (the same features in unique reference system), but with different points (5, 10, 20) concentration at each level. Then each cloud of points was independently analyzed by means of non-linear Least Squares, after estimated results have been reported. A MatLAB software tool used to generate new samples using bootstrap function. The results of the designed experiment are summarized and show that the bootstrap method provides the possibility to evaluate the uncertainty without repeating the Coordinate Measuring Machine (CMM) measurements many times, i.e. potentially can reduce the measuring time.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.586-590
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• 1990

In this paper we describe the shape measuring technique and system with a non-contractive sensor, composed of slit-ray projector and solid-state camera. For improving the accuracy and preventing measuring dead point, this sensor part is attached to the end of robot, and each sensing is executed after one step moving. By patching these sensing data, whole measuring data is constructed. The calibration between sensor and world coordinate is implemented through the specific calibration block by transformation matrix method. The result of experiment was satisfactory.

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.91-98
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• 2000

The three-dimensional unsteady compressible Full Navier-Stokes equation solver with sliding multi-block method has been applied to analyze three dimensional characteristics of the flow field and compression wave around the high speed train which Is entering into a tunnel. The numerical scheme of AF + ADI was used to efficiently solve Navier-Stokes equations in the curvilinear coordinate system. The vortex formation around the nose region was found and the generation of compression wave due to the blockage effects was observed ahead of the train in the form of plane wave. The three dimensional characteristics of the flow field compared to the analytic results were discussed in detail. The variation of pressure of tunnel wall surface and velocity profile of the train are identified as the train enters into a tunnel. The changes in aerodynamic forces and streamlines of each specific sections are also discussed and presented.

• Journal of computational fluids engineering
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• v.5 no.3
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• pp.23-31
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• 2000

The three-dimensional unsteady compressible Full Navier-Stokes equation solver with sliding multi-block method has been applied to analyze three dimensional characteristics of the viscous flow field and compression wave around the high speed train which is entering into a tunnel. The numerical scheme of AF + ADI was used to efficiently solve Navier-Stokes equations in the curvilinear coordinate system. The vortex formation owing to the viscous interaction around the train was found and the generation of compression wave due to the blockage effects was observed ahead of the train in the form of plane wave. The three dimensional characteristics of the flow field compared to the analytic results were discussed in detail. The variation of pressure of tunnel wall surface and velocity profile of the train are identified as the train enters into a tunnel. The changes in aerodynamic forces and streamlines of each specific sections are also discussed.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.137-140
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• 2002

In this paper, a new algorithm for two-dimensional (2-D) finite-difference time-domain (FDTD) method is presented. By this new method, the maximum time step size can be increased over the Courant-Friedrich-Levy (CFL) condition restraint. This new algorithm is adapted from an Alternating-Direction Implicit FDTD (ADI-FDTD) method. However, unlike the ADI-FDTD algorithm. the alternation is performed with respect to the blocks of fields rather than with respect to each respective coordinate direction. Moreover. this method can be efficiently simulated with parallel computation. and it is more efficient than the conventional FDTD method in terms of CPU time. Numerical formulations are shown and simulation results are presented to demonstrate the effectiveness and efficiency of our proposed method.

• Journal of KIISE:Software and Applications
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• v.31 no.1
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• pp.8-19
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• 2004

In this paper, we propose an efficient method for locating destination address block on both of machine-Printed and handwritten Korean mail piece images. The proposed method extracts connected components from the binary mail piece image, generates text lines by merging them, and then groups the text fines into nine clusters. The destination address block is determined by selecting some clusters. Considering the geometric characteristics of address information on Korean mail piece, we split a mail piece image into nine areas with an equal size. The nine clusters are initialized with the center coordinate of each area. A modified Manhattan distance function is used to compute the distance between text lines and clusters. We modified the distance function on which the aspect ratio of mail piece could be reflected. The experiment done with live Korean mail piece images has demonstrated the superiority of the Proposed method. The success rate for 1, 988 testing images was about 93.56%.

• Bulletin of the Korean Mathematical Society
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• v.55 no.3
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• pp.881-898
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• 2018

This article deals with implementation of a high-order finite difference scheme for numerical solution of the incompressible Navier-Stokes equations on curvilinear grids. The numerical scheme is based on pseudo-compressibility approach. A fifth-order upwind compact scheme is used to approximate the inviscid fluxes while the discretization of metric and viscous terms is accomplished using sixth-order central compact scheme. An implicit Euler method is used for discretization of the pseudo-time derivative to obtain the steady-state solution. The resulting block tridiagonal matrix system is solved by approximate factorization based alternating direction implicit scheme (AF-ADI) which consists of an alternate sweep in each direction for every pseudo-time step. The convergence and efficiency of the method are evaluated by solving some 2D benchmark problems. Finally, computed results are compared with numerical results in the literature and a good agreement is observed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.3
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• pp.174-181
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• 2011

A new registration method for IR image and EO image is proposed in this paper. IR sensor is applicable to many area because it absorbs thermal radiation energy unlike EO sensor does. However, IR sensor has difficulty to extract and match features due to low contrast compared to EO image. In order to register both images, we used modified SIFT(Scale Invariant Feature Transform) and block processing to increase feature distinctiveness. To remove outlier, we applied RANSAC(RANdom SAample Concensus) for each block. Finally, we unified matching features into single coordinate system and remove outlier again. We used 3~5um range IR image, and our experiment result showed good robustness in registration with IR image.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.389-400
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• 2007

Statement of problem. Use of the conventional dental impression procedure is problematic in patients who have difficulty opening their mouth, difficulty breathing through their nose or tendency to gag. Purpose. It is necessary to make individual trays more comfortable for patients during impression taking procedure. It was reported at the KAP Annual Meeting 2001 Seoul that an improved impression technique was suitable for this purpose. In this study, the accuracy of the improved dental impression method for implant was compared with the conventional dental impression method. Material and methods. An oral simulator was made from clear acrylic resin block which had similar form of edentulous ridge. For setting up the standard, five fixtures were installed on it. Study casts were made using two kinds of impression techniques. One was the conventional method that was taken using silicone impression material and an individual resin tray under connection of inter-fixture relation. The other was the improved method in which was the connection of the impression coping and the thermoformed polymethyl methacrylate tray. In addition, two different study casts were made from the improved impression body. The coordinates of the fixture on the study model were measured by three-dimensional coordinate measuring equipment. Then the distances between each fixture were calculated and compared with that of oral simulator. Accuracy of the each impression method was also assessed. Results. The differences of inter-fixture dimension between study casts and simulator in the improved impression technique showed $0.014{\pm}0.016mm$ and $0.017{\pm}0.022mm$, respectively and that of the conventional method was $0.017{\pm}0.014mm$. There was no significant difference between the improved impression technique and conventional method. Conclusion. The improved impression technique is useful for multiple support implants.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.1
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• pp.1-13
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• 2001

An absolutely passive fit at the interface with the superstructure and the abutment cylinders is need for implant longevity. In this study, a method of cast framework correction using spark erosion technology was evaluated. Electric discharge machining(EDM) is a process that uses electrical discharges, or sparks, to machine metal, The surface being machined is bombared with high-intensity electrical energy pulses that gradually melt away the stock until the desired configuration is obtained. Master model was fabricated by using metal block impression analogue, which fired 5 Branemark squared impression coping in an arc shaped metal block. Then framework using 4mm standard gold cylinder and type IV gold alloy was fabricated. In order to measure the fit of the framework we used both contact and noncontact coordinate measurement machine and data was processed by computer program. After superimposition of gold framework and master model numeric image data the distances between gold cylinder bearing surfaces and abutment replica bearing surfaces, and the angle deviations between gold cylinder and abutment replica centroid points were calculated. The results were as follows 1 The total mean distance (p<0.01) and standard deviation (p<0.001) between the gold cylinders and abutment bearing surfaces were significantly decreased after EDM 2. The total mean of maximum distances was significantly decreased after EDM (p<0.05). 3. After EDM, the mean angle deviation between centroid points was decreased.