• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.1-8
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• 2017

The purpose of this study is to propose a cache structure for processing large-volume building information modeling (BIM) geometry data,whereit is difficult to allocate physical memory. As the number of BIM orders has increased in the public sector, it is becoming more common to visualize and calculate large-volume BIM geometry data. Design and review collaboration can require a lot of time to download large-volume BIM data through the network. If the BIM data exceeds the physical free-memory limit, visualization and geometry computation cannot be possible. In order to utilize large amounts of BIM data on insufficient physical memory or a low-bandwidth network, it is advantageous to cache only the data necessary for BIM geometry rendering and calculation time. Thisstudy proposes acache structure for efficiently rendering and calculating large-volume BIM geometry data where it is difficult to allocate enough physical memory.

• Progress in Medical Physics
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• v.8 no.1
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• pp.17-24
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• 1997

We developed PC-based planning system for linear accelerator based stereotactic radiosurgery. The system was developed under Windows 95 on Pentium Pro$\^$(R) 200 ㎒ IBM PC with 128 MB RAM. It was programed using IDL$\^$(R)/ of Research Systems, Inc. as a programing tool. CT image data obtained with BRW stereotactic frame is transferred to PC through magnetoptical disk. As loading the image, the system automatically recognizes the location of rods and establishes stereotactic coordinates. It accurately calculates and corrects the coordinates, degree of tilting, and magnification rate of axial images. After the coordinates is defined we can delineate and edit the contours of target and organs of interest on axial images. Upon delineating contours of target, isocenter is determined automatically and we can set up the beam configuration for radiosurgery. The system provides beam's eye view and room's eye view for efficient confuguring of beams. The system calculates dose distribution 3-dimensionally. It takes 1 to 2 minutes to calculate dose distribution for 5 arcs. We can verify the dose distribution on serial axial images. We can analyze the dose distribution quantitatively by evaluation of dose-volume histogram of target and organ of interest. This system, PC-based radiosurgery planning system, includes the basic features for radiosurgery planning and calculates dose distribution within reasonable time for clinical application.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1069-1077
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• 2008

The railway abrasion measurement system have to satisfy two conditions to increase the measurement accuracy as follows. The laser region which is projected on the rail have to be extracted without the geometrical distortion. The mapping of the acquired laser region data on the rail profile have to be processed exactly. But, the conventional railway abrasion measurement system is deeply effected by the foreign substance( dust, rainwater, and so on ) on the railway or the sensitive response characteristic of the laser to the external measurement circumstance, and then the measurement errors arise from above factors. When the laser region is projected on the rail extracts from the acquired image, the interference of the light with the same frequency as the laser system occurs the serious problems. In the process of the mapping between the railway profile and the extracted laser region, the measurement accuracy is very highly effected by the geometrical distortion and the abnormal variation. In this Paper, we propose the novel method to increase the accuracy of the railway abrasion measurement dramatically. we designed and manufactured the high precision and fast image processing board with DSP Core and FPGA to measure the railway abrasion. The image processing board has the capability that the image of 1024X1280 from camera can be processed with the speed of 480 frame/sec. And, we apply the image processing algorithm base on the wavelet to extract the laser region is projected on the rail exactly. Finally, we developed high precision railway abrasion measurement system with the error range less than +/-0.5mm by which 2D image data is covered 3D data and mapped on the rail profile using the camera model and the perspective transform.

• Tunnel and Underground Space
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• v.26 no.5
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• pp.348-362
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• 2016

This study describes the results of blasting overbreak analysis using the stereo photogrammetry method in an underground mine. For comparing its quantitative measurements, LIDAR system was applied to the test site and blasting overbreak was analyzed for 4 test blasting operations. The difference in values obtained from the two methods showed only 0.81% in volume and 1.05% in area, respectively, therefore authors verify the field applicability of stereo photogrammetry method on underground mine. The volumes of overbreak measured from 4 test blastings were $29.84m^3$, $22.45m^3$, $14.54m^3$ and $5.46m^3$, respectively, in photogrammetry analysis on excavation surface, and it was shown that the volume of overbreak decreases with blasting sequence. From these measurements, it is concluded that the stereo photogrammetry method can describe the underground excavation surface effectively and the its quantitative data can be used for analysis of volume, area and overbreak of excavation zone.

• Journal of Sensor Science and Technology
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• v.10 no.5
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• pp.304-313
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• 2001

In this research, we investigate wet-etching properties of GaAs in $NH_4OH-H_2O_2-H_2O$, and develop the fabrication method of GaAs microstructures with rectangular cross section using (001) GaAs substrate. For obtaining wet-etching properties with respect to crystallographic orientation, the etch rates and cross-section etch profiles of (001) GaAs with 16 different compositions and the undercut rates with 5 different compositions are measured using $NH_4OH-H_2O_2-H_2O$ mixed solutions. From these experimental data, a new GaAs micromachining method in bulk (001) GaAs is proposed, and used to fabricate a released microbridges with a rectangular cross section. The developed GaAs micromachining method can be very useful for low-loss, highly-tunable capacitors for RF components and for integration with GaAs optical components.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1145-1152
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• 2011

This study was conducted to estimate genetic effects on economically important traits for genetic improvement in Hanwoo by using the real-time ultrasound measurements for longissimus dorsi muscle area (LMA), backfat thickness (BFT), and marbling score (Marb). The phenotypic data were obtained from 1,648 pedigreed cows, and general linear models were applied to test the effects of age, region, and body condition socre. The cows between 50 and 60 months of age had the greatest scores for LMA and BFT, and Marb (P<0.05). The cows in region C had the greatest scores for body condition socre, LMA and BFT, while in region J Marb was the lowest (P<0.05). There was positive relation with LMA, BFT, and Marb according to increase body condition socre. Heritabilities for LMA, BFT, and Marb were estimated as 0.136, 0.351, and 0.236, respectively. These results would provide primary information for the efficient implementation of genetic improvement schemes in Hanwoo.

• Composites Research
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• v.36 no.1
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• pp.48-52
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• 2023

Fiber-reinforced composites have anisotropic material properties, so the mechanical properties of composite structures can vary depending on the stacking sequence. Therefore, it is essential to design the proper stacking sequence of composite structures according to the functional requirements. However, depending on the manufacturing condition or the shape of the structure, there are many cases where the designed stacking angle is out of range, which can affect structural performance. Accordingly, it is important to analyze the stacking angle in order to confirm that the composite structure is correctly fabricated as designed. In this study, the stacking angle was predicted from real cross-sectional images of fiber-reinforced composites using convolutional neural network (CNN)-based deep learning. Carbon fiber-reinforced composite specimens with several stacking angles were fabricated and their cross-sections were photographed on a micro-scale using an optical microscope. The training was performed for a CNN-based deep learning model using the cross-sectional image data of the composite specimens. As a result, the stacking angle can be predicted from the actual cross-sectional image of the fiber-reinforced composite with high accuracy.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.109-113
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• 1997

Purpose: To evaluate the differences of functional imaging patterns between conventional spoiled gradient echo (SPGR) and echo planar imaging (EPI) methods in cerebral motor cortex activation. Materials and Methods: Functional MR imaging of cerebral motor cortex activation was examined on a 1.5T MR unit with SPGR (TRfrE/flip angle=50ms/4Oms/$30^{\circ}$, FOV=300mm, matrix $size=256{\times}256$, slice thickness=5mm) and an interleaved single shot gradient echo EPI (TRfrE/flip angle = 3000ms/40ms/$90^{\circ}$, FOV=300mm, matrix $size=128{\times}128$, slice thickness=5mm) techniques in five male healthy volunteers. A total of 160 images in one slice and 960 images in 6 slices were obtained with SPGR and EPI, respectively. A right finger movement was accomplished with a paradigm of an 8 activation/ 8 rest periods. The cross-correlation was used for a statistical mapping algorithm. We evaluated any differences of the time series and the signal intensity changes between the rest and activation periods obtained with two techniques. Also, the locations and areas of the activation sites were compared between two techniques. Results: The activation sites in the motor cortex were accurately localized with both methods. In the signal intensity changes between the rest and activation periods at the activation regions, no significant differences were found between EPI and SPGR. Signal to noise ratio (SNR) of the time series data was higher in EPI than in SPGR by two folds. Also, larger pixels were distributed over small p-values at the activation sites in EPI. Conclusions: Good quality functional MR imaging of the cerebral motor cortex activation could be obtained with both SPGR and EPI. However, EPI is preferable because it provides more precise information on hemodynamics related to neural activities than SPGR due to high sensitivity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.86-93
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• 2010

The wear of railway track affects loss of rough ride, noise or vibration of train and traveling safety. Moreover as the track is worn away, this promotes destruction of structural mechanism of rail track which can bring about increasing of rail track maintenance cost drastically. For this reason, it is very important and interested research subject to design railway track structure and to analyse train movement mechanism based on systematic analysis of the reasons causing rail wear possible in real field. In this research, for the efficient maintenance, Life Cycle Performance of rail track and maintenance characteristics are computed considering some track components such as track type, contracting type, sleeper type and roadbed type. Time - Wear probabilistic distribution relationship as well as multiple regression analysis based on time, curvature and wear data are computed to predict the service life remainder of railway track and to be adapted to safety assessment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.775-780
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• 2007

Rapid Prototyping (RP) is a technology that produces prototype parts from 3D computer aided design model data without intermediate processing technology rapidly. CAD model data are created from 3D object digitizing systems but presented just as 2D data when they are printed as a hard copy or displayed on a monitor. However, Rapid Prototyping Technology fabricates 3D objects the same that CAD data because it transforms designed 3D CAD data into 2D cross sectional data, and manufactures layer by layer deposition sequentially. But most of all the small and medium scale companies which produce a toothbrush, a toy and such like provisions are in difficult situations to buy RP system because it is very expensive. In this paper, we propose a 3D control system adopting open source programs for implementing Rapid Prototyping Technology in order that RP system can be purchase at a moderate price.