• Journal of Korean Neurosurgical Society
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• v.60 no.3
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• pp.289-293
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• 2017

An exoscope, high-definition video telescope operating monitor system to perform microsurgery has recently been proposed an alternative to the operating microscope. It enables surgeons to complete the operation assistance by visualizing magnified images on a display. The strong points of exoscope are the wide field of view and deep focus. It minimized the need for repositioning and refocusing during the procedure. On the other hand, limitation of magnifying object was an emphasizing weak point. The procedures are performed under 2D motion images with a visual perception through dynamic cue and stereoscopically viewing corresponding to the motion parallax. Nevertheless, stereopsis is required to improve hand and eye coordination for high precision works. Consequently novel 3D high-definition operating scopes with various mechanical designs have been developed according to recent high-tech innovations in a digital surgical technology. It will set the stage for the next generation in digital image based neurosurgery.

• Steel and Composite Structures
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• v.31 no.4
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• pp.397-408
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• 2019

In this paper, a geometrically nonlinear meshfree analysis of 3D various forms of shell structures using the double director shell theory with finite rotations is proposed. This theory is introduced in the present method to remove the shear correction factor and to improve the accuracy of transverse shear stresses with the consideration of rotational degrees of freedom.The present meshfree method is based on the radial point interpolation method (RPIM) which is employed for the construction of shape functions for a set of nodes distributed in a problem domain. Discrete system of geometrically nonlinear equilibrium equations solved with the Newton-Raphson method is obtained by incorporating these interpolations into the weak form. The accuracy of the proposed method is examined by comparing the present results with the accurate ones available in the literature and good agreements are found.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.1
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• pp.25-36
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• 2020

Motivation: Fibers as the extracellular filamentous structures determine the shape of the cytoskeletal structures. Their characterization and reconstruction from a 3D cellular image represent very useful quantitative information at the cellular level. In this paper, we presented a novel automatic method to extract fiber diameter distribution through a pipeline to reconstruct fibers from 3D fluorescence confocal images. The pipeline is composed of four steps: segmentation, skeletonization, template fitting and fiber tracking. Segmentation of fiber is achieved by defining an energy based on tensor voting framework. After skeletonizing segmented fibers, we fit a template for each seed point. Then, the fiber tracking step reconstructs fibers by finding the best match of the next fiber segment from the previous template. Thus, we define a fiber as a set of templates, based on which we calculate a diameter distribution of fibers.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.229-240
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• 2019

3D geo-spatial model have been widely used in the field of Civil Engineering, Medical, Computer Graphics, Urban Management and many other. Especially, the demand for high quality 3D spatial information such as precise road map construction has explosively increased, MMS and UAV techniques have been actively used to acquire them more easily and conveniently in surveying and geo-spatial field. However, in order to perform 3D modeling by integrating the two data set from MMS and UAV, its so needed an proper registration method is required to efficiently correct the difference between the raw data acquisition sensor, the point cloud data generation method, and the observation accuracy occurred when the two techniques are applied. In this study, we obtained UAV point colud data in Yeouido area as the study area in order to determine the automatic registration performance between MMS and UAV point cloud data using ICP(Iterative Closet Point) method. MMS observations was then performed in the study area by dividing 4 zones according to the level of overlap ratio and observation noise with based on UAV data. After we manually registered the MMS data to the UAV data, then compared the results which automatic registered using ICP method. In conclusion, the higher the overlap ratio and the lower the noise level, can bring the more accurate results in the automatic registration using ICP method.

• Journal of KIISE
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• v.43 no.5
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• pp.562-568
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• 2016

Point cloud data can be expressed in a specific coordinate system of a data set with a large number of points, to represent any form that generally has different characteristics in the three-dimensional coordinate space. This paper is aimed at finding a cylindrical pipe in the point cloud of the three-dimensional coordinate system using RANSAC, which is faster than the conventional Hough Transform method. In this study, the proposed cylindrical pipe is estimated by combining the results of parameters based on two mathematical models. The two kinds of mathematical models include a sphere and line, searching the sphere center point and radius in the cylinder, and detecting the cylinder with straightening of center. This method can match cylindrical pipe with relative accuracy; furthermore, the process is rapid except for normal estimation and segmentation. Quick cylinders matching could benefit from laser scanning and reverse engineering construction sectors that require pipe real-time estimates.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1330-1339
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• 2022

3D object detection generally aims to detect relatively large data such as automobiles, buses, persons, furniture, etc, so it is vulnerable to small object detection. In addition, in an environment with limited resources such as embedded devices, it is difficult to apply the model because of the huge amount of computation. In this paper, the accuracy of small object detection was improved by focusing on local features using only one layer, and the inference speed was improved through the proposed knowledge distillation method from large pre-trained network to small network and adaptive quantization method according to the parameter size. The proposed model was evaluated using SUN RGB-D Val and self-made apple tree data set. Finally, it achieved the accuracy performance of 62.04% at mAP@0.25 and 47.1% at mAP@0.5, and the inference speed was 120.5 scenes per sec, showing a fast real-time processing speed.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.329-336
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• 2014

Purpose : To evaluate the dose on a contralateral breast and the usefulness of shielding according to the distance between the contralateral breast and the side of the beam by breast size when patients who got breast implant receive radiation therapy. Materials and Methods : We equipped 200 cc, 300 cc, 400 cc, and 500 cc breast model on the human phantom (Rando-phantom), acquired CT images (philips 16channel, Netherlands) and established the radiation treatment plan, 180 cGy per day on the left breast (EclipseTM ver10.0.42, Varian Medical Systems, USA) by size. We set up each points, A, B, C, and D on the right(contralateral) breast model for measurement by size and by the distance from the beam and attached MOSFET at each points. The 6 MV, 10 MV and 15 MV X-ray were irradiated to the left(target) breast model and we measured exposure dose of contralateral breast model using MOSFET. Also, at the same condition, we acquired the dose value after shielding using only Pb 2 mm and bolus 3 mm under the Pb 2 mm together. Results : As the breast model is bigger from 200 cc to 500 cc, The surface of the contralateral breast is closer to the beam. As a result, from 200 cc to 500 cc, on 180 cGy basis, the measurement value of the scattered ray inclined by 3.22 ~ 4.17% at A point, 4.06 ~ 6.22% at B point, 0.4~0.5% at C point, and was under 0.4% at D point. As the X-ray energy is higher, from 6 MV to 15 MV, on 180 cGy basis, the measurement value of the scattered ray inclined by 4.06~5% at A point, 2.85~4.94% at B point, 0.74~1.65% at C point, and was under 0.4% at D point. As using Pb 2 mm for shield, scattered ray declined by average 9.74% at A and B point, 2.8% at C point, and is under 1% at D point. As using Pb 2 mm and bolus together for shield, scattered ray declined by average 9.76% at A and B point, 2.2% at C point, and is under 1% at D point. Conclusion : Commonly, in case of patients who got breast implant, there is a distance difference by breast size between the contralateral breast and the side of beam. As the distance is closer to the beam, the scattered ray inclined. At the same size of the breast, as the X-ray energy is higher, the exposure dose by scattered ray tends to incline. As a result, as low as possible energy wihtin the plan dose is good for reducing the exposure dose.

• Kyungpook Mathematical Journal
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• v.50 no.4
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• pp.537-543
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• 2010

Let X be a regular $T_1$-space such that each single point set is a $G_{\delta}$ set. Denot 'hereditarily closure-preserving' by 'HCP'. To consider a question of closed maps of S. Lin in [6], we improve some results of Foged in [1], and prove the following propositions. Proposition 1. $D\;=\;\{x{\in}X\;:\;\mid\{F{\in}\cal{F}:x{\in}F\}\mid{\geq}{\aleph}_0\}$ is discrete and closed if $\cal{F}$ is a collection of HCP. Proposition 2. $\cal{H}\;=\;\{{\cup}\cal{F}'\;:\;F'$ is an fininte subcolletion of $\cal{F}_n\}$ is HCP if $\cal{F}$ is a collection of HCP. Proposition 3. Let (X,$\tau$) have a $\sigma$-HCP k-network. Then (X,$\tau$) has a $\sigma$-HCP k-network F = ${\cup}_n\cal{F}_n$ such that such tat: (i) $\cal{F}_n\;\subset\;\cal{F}_{n+1}$, (ii) $D_n\;=\;\{x{\in}X\;:\;\mid\{F{\in}\cal{F}_n\;:\;x{\in}F\}\mid\;{\geq}\;{\aleph}_0\}$ is a discrete closed set and (iii) each $\cal{F}_n$ is closed to finite intersections.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.3
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• pp.825-831
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• 1996

Using the two-dimensional hydrocode HI-DYNA2D, a calculation on the explosive selding of dissimilar plates(Steel Titanium) was made for the pressure, temperature, velocity and impact ingles adjacent to the collision point during the welding process. The FEM result indicates that optimal stand-off distance of initially parallel set-up is 3-5mm for various values of the explosive thickness. The calculation shows that when the explosive thickness is around 30mm, the temperature of welding point which is strongly related to the metallic jet formation is 2, 000-3, 500K for the given stand-off distance.

• Cartoon and Animation Studies
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• s.34
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• pp.105-128
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• 2014

This study was aimed to analyze the disparities of 3D stereoscopic images in four well-known American animation movies. After Avatar (2009), lots of stereoscopic movies were developed in Korean 3D production. Almost all 3D productions in Korea, however, focus on the display images or TV series animation yet. In order to make many well-made Korean stereoscopic 3D animations in future, analyzing and comparing the disparities of 3D stereoscopic images is necessary and even mandated. First, I chose 40 cuts from each four American stereoscopic 3D feature films, including Despicable me 2, Epic, Monster University, and Turbo. According to the classifications of shot angles by Vineyard (2008), secondly I analyze the 23 different angular disparities of 3D stereoscopic images and displayed in tables. Demonstrated shot angle disparities in each scene would provide numerical information to animators how to design and make the 3D stereoscopic images. Making successful stereoscopic 3D feature film will be a huge turning point in the Korean animation field in future. This study would be a first trial to seek a new method to set ahead an outlook of numerical values of 3D stereoscopic images for better visual effects.