• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1748-1753
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• 2003

3D-PTV measurement was conducted on the wake of a sphere. The Reynolds number is 1130 with the diameter(d=30mm). The measurement system consisted of three CCD cameras, an image grabber, an Ar-Ion laser and a host computer. An eigenvalue analysis was introduced for the analysis on the wake. Statistical turbulent properties were quantitatively clarified using the time-consecutive instantaneous three-dimensional vectors obtained by the 3D-PTV system. The spatial distributions of the sphere wake showed strong relations with spiral motions of the vortcies shedded from the surface of the sphere.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.347-351
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• 2010

In this paper, our effort to apply 3-D Virtual Reality system for stereoscopic visualization of flow data is briefly described. This study is an extension of our previous and on-going research efforts to develop DATA(Data Analysis and Visualization Application) program, which is a data visualization program developed by using Qt as GUI development environment and OpenGL as graphic library. The program is developed upon the framework of object-oriented programming and it was originally developed by using Qt 3.3.3 environment. In this research the program is converted into a Qt 4.3.3-compatible version, and this new version is developed on Visual Studio 2005. And to achieve a stereoscopic viewing capability, two graphic windows are used to render its own viewing image for the lift and right eye respectively. These two windows are merged into one image using 3D monitor and the viewers can see the data visualization results with stereoscopic depth effects by using polarizing glasses. In this paper three dimensional data visualization with stereoscopic technique combined with 3D Monitor is demonstrated, and the current achievement would be a good start-up for further development of low-cost high-quality stereoscopic data visualization system.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.195-201
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• 2014

In this study, face recognition system was designed based on polynomial Radial Basis Function Neural Networks(pRBFNNs) pattern classifier using 2-directional 2-dimensional principal component analysis algorithm. Existing one dimensional PCA leads to the reduction of dimension of image expressed by the multiplication of rows and columns. However $(2D)^2PCA$(2-Directional 2-Dimensional Principal Components Analysis) is conducted to reduce dimension to each row and column of image. and then the proposed intelligent pattern classifier evaluates performance using reduced images. The proposed pRBFNNs consist of three functional modules such as the condition part, the conclusion part, and the inference part. In the condition part of fuzzy rules, input space is partitioned with the aid of fuzzy c-means clustering. In the conclusion part of rules. the connection weight of RBFNNs is represented as the linear type of polynomial. The essential design parameters (including the number of inputs and fuzzification coefficient) of the networks are optimized by means of Differential Evolution. Using Yale and AT&T dataset widely used in face recognition, the recognition rate is obtained and evaluated. Additionally IC&CI Lab dataset is experimented with for performance evaluation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.4
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• pp.368-375
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• 2008

In this paper, we calculated the pixel and all the inter-electrode capacitances in a unit pixel of three kinds of TFT-LCD modes in order to realize the full color image. And we analyzed the effect on applied voltage. We fixed size of sub-pixel and designed a unit pixel of three kinds of TFT-LCD modes. We calculated rigorously the pixel and all the inter-electrode capacitances by the three dimensional simulation. And we expanded one pixel into whole panel using H-SPICE. As a result, we calculated the RMS voltage and kickback voltage which most affect gray scale of the pixel and calculated the number of bit according to permissible range of minimum gray scale using V-T curve.

• Journal of the Ergonomics Society of Korea
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• v.34 no.6
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• pp.583-595
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• 2015

Objective: The purpose of this study was to determine the reliability of lower limb joint angles computed with the software ImageJ during jumping movements. Background: Kinematics is the study of bodies in motion without regard to the forces or torques that may produce the motion. The most common method for collecting motion data uses an imaging and motion-caption system to record the 2D or 3D coordinates of markers attached to a moving object, followed by manual or automatic digitizing software. Above all, passive optical motion capture systems (e.g. Vicon system) have been regarded as the gold standards for collecting motion data. On the other hand, ImageJ is used widely for an image analysis as free software, and can collect the 2D coordinates of markers. Although much research has been carried out into the utilizations of the ImageJ software, little is known about their reliability. Method: Seven healthy female students participated as the subject in this study. Seventeen reflective markers were attached on the right and left lower limbs to measure two and three-dimensional joint angular motions. Jump performance was recorded by ten-vicon camera systems (250Hz) and one digital video camera (240Hz). The joint angles of the ankle and knee joints were calculated using 2D (ImageJ) and 3D (Vicon-MX) motion data, respectively. Results: Pearson's correlation coefficients between the two methods were calculated, and significance tests were conducted (${\alpha}=1%$). Correlation coefficients between the two were over 0.98. In Vicon-MX and ImageJ, there is no systematic error by examination of the validity using the Bland-Altman method, and all data are in the 95% limits of agreement. Conclusion: In this study, correlation coefficients are generally high, and the regression line is near the identical line. Therefore, it is considered that motion analysis using ImageJ is a useful tool for evaluation of human movements in various research areas. Application: This result can be utilized as a practical tool to analyze human performance in various fields.

• Journal of the Korean Society of Visualization
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• v.9 no.4
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• pp.63-68
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• 2011

The flow-field of a liquid-metal system is very important for the safety analysis and the design of the steam generator of liquid-metal fast breeder reactor. Dynamic neutron radiography (DNR) is suitable for a visualization and measurement of a liquid metal flow and a two-phase flow in a metallic duct. However, the three dimensional DNR techniques is not enough to obtain the velocity information in the wide channel up to now. In this research, a high speed DNR technique was applied to visualize the heavy liquid-metal flow field in the narrow channel with the HANARO-beam facility. The images were taken with a high frame-rate neutron radiography at 250 fps and analyzed with a Particle Image Velocimetry(PIV) method. The images were compared with the results of the commercial CFX code to study the feasibility of DNR technique for the measuring the heavy liquid-metal flow field. The PIV images could discern the turbulent vortex flow in the two-dimensional narrow channel.

• Journal of KSNVE
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• v.10 no.1
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• pp.49-56
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• 2000

In this paper performance of the noise barrier which is 53 m long and 6m high, and is located between the high rise apartment and road, is studied by using experimental and analytic method. The insertion loss is measured by using the direct method in accordance with the ISO code, while theoretical prediction is based on Muradali and Fyfe's method (Applied Acoustics, Vol. 53, 49~75, 1998). In addition to the diffraction at the top of the barrier, the waves are reflected infinite times between the building and the barrier, which is equivalent to replacing the building by the infinite series of the image receiver points. In two-dimensional study, the prediction of the insertion loss results in significantly overestimated values compared with the measurement. However three-dimensional analysis shows reasonable agreements, where traffic noise is assumed as incoherent line source and the length of the source is larger than that of the barrier.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.108-114
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• 2006

Transient and asymmetric density distributions of butane flow have been investigated from laser image signals by developed three-dimensional digital speckle tomography. Moved signals of speckles have been captured by multiple CCD images in three angles of view simultaneously because the flows were asymmetric and transient. The signals of speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays fur density gradients. The three-dimensional density fields have been reconstructed from the fringe shift signal which is integrated from the deflection angle by a real-time multiplicative algebraic reconstruction technique (MART).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.49.1-49.9
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• 2016

Background: The aim of this report is to present a new reference for aesthetic mandible surgery using three-dimensional cone-beam computed tomography-based treatment planning for orthognathic surgery which can be implemented in surgical planning and perioperative procedure. Methods: To make an objective standard for evaluating aesthetic mandibular outline, we make an aesthetic scoring criteria with consideration of asymmetry, broad mandibular border line, and prominent mandibular angle. Two maxillofacial surgeons and two orthodontists rated their aesthetical evaluation from 1 to 5. Experimental group consisting of 47 female and 38 male patients who had rotational orthognathic two-jaw surgery from 2010 to 2011 were chosen according to aesthetic scoring done by two maxillofacial surgeons and two orthodontists. A high aesthetic score (${\geq}16$) means the facial contour is symmetric, with no broad and narrow aesthetic mandible frontal profiles. Control A group consisted of ten female and ten male patients who had no orthognathic surgery experience and low aesthetic score (${\geq}10$). Control B group consisted of ten female and ten male patients who had no orthognathic surgery experience and had anaesthetic mandibular frontal profile and a high aesthetic score (${\geq}16$). The three-dimensional image of the patient was taken from dental cone-beam CT (DCT) scanning (experimental group and control A group: 6 months DCT after surgery, control B group: 1st visit DCT). Each DCT was reformatted to reorient the 3D image using 3D analyzing program (OnDemand3D, cybermed Inc, CA, USA). After selection of 12 landmarks and the construction of reoriented horizontal, vertical, and coronal reference lines, 15 measurements were taken in 3D analysis of frontal mandibular morphology. Afterwards, horizontal and vertical linear measurements and angular measurements, linear ratio were obtained. Results: Mean $Go^{\prime}_{Rt}-Me^{\prime}-Go^{\prime}_{Lt}$ angular measurement was $100.74{\pm}2.14$ in female patients and $105.37{\pm}3.62$ in male patients. These showed significant difference with control A group in both genders. Ratio of $Go^{\prime}_{Rt}-Go^{\prime}_{Lt}-Me^{\prime}$ length to some linear measurements (ratio of $Me^{\prime}-Cd^{\prime}_{Rt}Cd^{\prime}_{Lt}$ to $Me^{\prime}-Go^{\prime}_{Rt}Go^{\prime}_{Lt}$, ratio of $Me^{\prime}-Go^{\prime}$ to $Me^{\prime}-Go^{\prime}_{Rt}Go^{\prime}_{Lt}$, ratio of $Go^{\prime}_{Rt}-Go^{\prime}_{Lt}$ to $Me^{\prime}-Go^{\prime}_{Rt}Go^{\prime}_{Lt}$) showed significant difference with control A group in both genders. Conclusion: This study was intended to find some standard measurement of mandible frontal view in 3D analysis of aesthetic patient. So, these potential measurement value may be helpful for orthognathic treatment planning to have more aesthetic and perspective outcomes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.3194-3216
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• 2018

Slow Feature Discriminant Analysis (SFDA) is a supervised feature extraction method inspired by biological mechanism. In this paper, a novel method called Two Dimensional Slow Feature Discriminant Analysis via $L_{2,1}$ norm minimization ($2DSFDA-L_{2,1}$) is proposed. $2DSFDA-L_{2,1}$ integrates $L_{2,1}$ norm regularization and 2D statically uncorrelated constraint to extract discriminant feature. First, $L_{2,1}$ norm regularization can promote the projection matrix row-sparsity, which makes the feature selection and subspace learning simultaneously. Second, uncorrelated features of minimum redundancy are effective for classification. We define 2D statistically uncorrelated model that each row (or column) are independent. Third, we provide a feasible solution by transforming the proposed $L_{2,1}$ nonlinear model into a linear regression type. Additionally, $2DSFDA-L_{2,1}$ is extended to a bilateral projection version called $BSFDA-L_{2,1}$. The advantage of $BSFDA-L_{2,1}$ is that an image can be represented with much less coefficients. Experimental results on three face databases demonstrate that the proposed $2DSFDA-L_{2,1}/BSFDA-L_{2,1}$ can obtain competitive performance.