• Journal of Korea Multimedia Society
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• v.4 no.6
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• pp.518-523
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• 2001

This paper proposes the new method which is adopted in extracting character features and recognizing characters using fractal dimension of the Chaos theory which highly recolonizes a minute difference with strange attractor created from Henon system. This paper implements a high precision character recognition system. firstly, it gets features of mesh, projection and cross distance feature from character images. And their feature is converted into data of time series. Then using modified Henon system suggested in this paper, each characters attractor about standard Korean Character, KSC 5601 is reconstructed. Secondly, in order to analyze the Chaotic degree of each characters attractor, it gets last features of character image after calculating box-counting Dimension, Natural Measure, Information Bit, Information Dimension which are meant fractal dimension. An experimental result shows 97.49% character classification rates for 2350 Korean characters using proposed method in this paper.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.2
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• pp.93-102
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• 1991

This study aims to develop techniques for generating Digital Elevation Model(DEM) from SPOT Computer Compatible Tape(CCT) data, so as to present an effective way of generation of DEM for large area. As the first phase of extracting ground heights from SPOT stereo digital data, the bundle adjustment technique was used to determine the satellite exterior orientation parameters. Because SPOT data has the characteristics of multiple perspective projection, exterior orientation Parameters were modelled as a function of scan lines. In the second phase, a normalized cross correlation matching technique was applied to search for the conjugate pixels ill stereo pairs. The preliminary study showed that the matching window size of 13$\times$13 was adequate. After image coordinates of the conjugate pixels were determined by the matching technique, the ground coordinates of the corresponding pixels were calculated by the space intersection method. Then DEM was generated by interpolations. In addtion an algorithm for the elimination of abnormal elevation was developed and applied. The algorithm was very effective to improve the accuracy of the generated DEM.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.503-526
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• 2016

In-plane and out-of-plane free vibration analysis of Timoshenko curved beams is addressed based on the isogeometric method, and an effective scheme to avoid numerical locking in both of the two patterns is proposed in this paper. The isogeometric computational model takes into account the effects of shear deformation, rotary inertia and axis extensibility of curved beams, and is applicable for uniform circular beams, and more complicated variable curvature and cross-section beams as illustrated by numerical examples. Meanwhile, it is shown that, the $C^{p-1}$-continuous NURBS elements remarkably have higher accuracy than the finite elements with the same number of degrees of freedom. Nevertheless, for in-plane or out-of-plane vibration analysis of Timoshenko curved beams, the NURBS-based isogeometric method also exhibits locking effect to some extent. To eliminate numerical locking, the selective reduced one-point integration and $\bar{B}$ projection element based on stiffness ratio is devised to achieve locking free analysis for in-plane and out-of-plane models, respectively. The suggested integral schemes for moderately slender models obtain accurate results in both dominated and non-dominated regions of locking effect. Moreover, this strategy is effective for beam structures with different slenderness. Finally, the influence factors of structural parameters of curved beams on their natural frequency are scrutinized.

• Laser Solutions
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• v.6 no.3
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• pp.19-28
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• 2003

The manufacturing process for the microfluidic device can include sequential steps such as master fabrication, electroforming, and injection molding. The laser ablation, using masks, has been applied to the fabrication of channels in microfluidic devices. In this research, an excimer laser was used to engrave microscopic channels on the surface of PET (polyethylene terephthalate), which shows a high absorption ratio for an excimer laser beam with a wavelength of 248 m. When 50-${\mu}{\textrm}{m}$-wide rectangular microscopic channels are ablated with a 500 ${\times}$ 500 ${\mu}{\textrm}{m}$ square mask at a magnification ratio of 1/10, ditch-shaped defects were found in both corners. The measurement of laser beam intensity showed that a coherent image in the PET target caused such defects. Analysis based on the Fourier diffraction theory enabled the prediction of the coherent shape at the image surface as well as the diffraction beam shape between the mask and the image surface. It also showed that the diameter of the aperture had a dominant effect. The application of aperture with a diameter of less than 3 mm helped to eliminate such defects in the ablated rectangular microscopic channels on PET without such ditch-shaped defects.

• Journal of Auto-vehicle Safety Association
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• v.16 no.3
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• pp.64-71
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• 2024

With the advent of Level 4 autonomous vehicles, the need for effective communication between these vehicles and pedestrians has become increasingly important. To address this, eHMI (Enhanced Human-Machine Interface) technology has been proposed to replace traditional driver-pedestrian interactions. eHMI plays a crucial role in conveying the vehicle's status and intentions to pedestrians, thereby improving interaction. Globally, automobile manufacturers and technology companies are investing in visual eHMI technologies, advancing in tandem with the automotive industry. This study developed a methodology for field evaluation of communication technologies between pedestrians and Level 4 autonomous vehicles in urban settings. A three-stage message and display system, tailored to the pedestrian crossing process (recognition, judgment, response), was established. In experiments without message displays, 42.2% (38 out of 90) of participants abandoned crossing. Most who crossed did so only after the vehicle stopped, with some groups crossing irrespective of vehicle approach. When the 'yield' message was introduced, crossing patterns and speed distributions changed significantly. All 38 participants who initially abandoned crossing decided to cross, and the elderly who previously ran or walked quickly crossed at a normal pace, reducing overall crossing time. Field experiments are crucial as real-world conditions may elicit different behaviors than controlled settings. Continued research in field evaluations is essential to develop and assess effective eHMI messages. By observing and analyzing actual pedestrian movements, we can reliably evaluate the effectiveness of these communication technologies, thereby enhancing interaction between autonomous vehicles and pedestrians.

• Anatomy & Biological Anthropology
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• v.31 no.4
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• pp.133-142
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• 2018

3D histology is a imaging system for the 3D structural information of cells or tissues. The synchrotron radiation propagation phase contrast micro-CT has been used in 3D imaging methods. However, the simple phase contrast micro-CT did not give sufficient micro-structural information when the specimen contains soft elements, as is the case with many biomedical tissue samples. The purpose of this study is to develop a new technique to enhance the phase contrast effect for soft tissue imaging. Experiments were performed at the imaging beam lines of Pohang Accelerator Laboratory (PAL). The biomedical tissue samples under frozen state was mounted on a computer-controlled precision stage and rotated in $0.18^{\circ}$ increments through $180^{\circ}$. An X-ray shadow of a specimen was converted into a visual image on the surface of a CdWO4 scintillator that was magnified using a microscopic objective lens(X5 or X20) before being captured with a digital CCD camera. 3-dimensional volume images of the specimen were obtained by applying a filtered back-projection algorithm to the projection images using a software package OCTOPUS. Surface reconstruction and volume segmentation and rendering were performed were performed using Amira software. In this study, We found that synchrotron phase contrast imaging of frozen tissue samples has higher contrast power for soft tissue than that of non-frozen samples. In conclusion, synchrotron radiation propagation phase contrast cryo-microCT imaging offers a promising tool for non-destructive high resolution 3D histology.

• The Journal of Engineering Geology
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• v.19 no.4
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• pp.517-528
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• 2009

Statistical analyses of cut-slope stability were performed over approximately 5.7 km section along the National road No. 25, which cross-cuts in NW-SE direction the Cheongwon and Boeun-Gun area, Chungbuk. A measure of slope-stability was established by using direct reinforcement and indirect protection methods in whole section. Orientations(dip/dip direction) of the slopes, foliations(bedding), cleavages and joints were measured in total of 30 slope sites. The results analyzed using stereographic projection indicate that major directions of the slopes come out predominantly in three directions: 1) $58^{\circ}/095^{\circ}$, 2) $60^{\circ}/296^{\circ}$ and 3) $59^{\circ}/212^{\circ}$. In analyses of dip direction and frequency of cut-slopes established by reinforcement and protection methods, slopes with dip direction of $80-120^{\circ}$ and $280-320^{\circ}$ mostly occur. However, slopes with dip direction of $0-80^{\circ}$(N and NW) and $120-160^{\circ}$(SE) are not distributed in the study area. Failure aspects were analyzed for three major directions of the slopes, respectively. The results of failure aspects analyzed indicate that slopes in the study area could generate various failures as the results of intersection and/or intersection combination among joints, foliations(bedding) and cleavages. However, possibility of failure in a slope of major direction No. 3 is statistically very low because of low frequency in total number of slopes with the direction and of formation of small scale-slopes geographically, although the slope might generate all aspects of failure-modes.

• Progress in Medical Physics
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• v.27 no.1
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• pp.1-7
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• 2016

In this work, we considered a compressed-sensing (CS)-based image deblurring scheme with a total-variation (TV) regularization penalty for improving image characteristics in digital tomosynthesis (DTS). We implemented the proposed image deblurring algorithm and performed a systematic simulation to demonstrate its viability. We also performed an experiment by using a table-top setup which consists of an x-ray tube operated at $90kV_p$, 6 mAs and a CMOS-type flat-panel detector having a $198-{\mu}m$ pixel resolution. In the both simulation and experiment, 51 projection images were taken with a tomographic angle range of ${\theta}=60^{\circ}$ and an angle step of ${\Delta}{\theta}=1.2^{\circ}$ and then deblurred by using the proposed deblurring algorithm before performing the common filtered-backprojection (FBP)-based DTS reconstruction. According to our results, the image sharpness of the recovered x-ray images and the reconstructed DTS images were significantly improved and the cross-plane spatial resolution in DTS was also improved by a factor of about 1.4. Thus the proposed deblurring scheme appears to be effective for the blurring problems in both conventional radiography and DTS and is applicable to improve the present image characteristics.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.457-465
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• 2013

We integrated and correlated datasets from surface and subsurface geophysics, drilling cores, and engineering geology to identify geological interfaces and characterize the joints and fracture zones within the rock mass. The regional geometry of a geologically weak zone was investigated via a fence projection of electrical resistivity data and a borehole image-processing system. Subsurface discontinuities and intensive fracture zones within the rock mass are delineated by cross-hole seismic tomography and analyses of dip directions in rose diagrams. The dynamic elastic modulus is studied in terms of the P-wave velocity and Poisson's ratio. Subsurface discontinuities, which are conventionally identified using the N value and from core samples, can now be identified from anomalous reflection coefficients (i.e., acoustic impedance contrast) calculated using a pair of well logs, comprising seismic velocity from suspension-PS logging and density from logging. Intensive fracture zones identified in the synthetic seismogram are matched to core loss zones in the drilling core data and to a high concentration of joints in the borehole imaging system. The upper boundaries of fracture zones are correlated to strongly negative amplitude in the synthetic trace, which is constructed by convolution of the optimal Ricker wavelet with a reflection coefficient. The standard deviations of dynamic elastic moduli are higher for fracture zones than for acompact rock mass, due to the wide range of velocities resulting from the large numbers of joints and fractures within the zone.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.87-93
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• 2006

Inventories, and characteristics such as dimension, fuel rod array, weight, $^{235}U$ enrichment, and discharge burnup of spent nuclear fuel (SNF) generated from existing and planed nuclear power plants based on National 2nd Basic Plan for Electric Power Demand and Supply were investigated and projected to support geological disposal system design. The historical and projected inventory by the end 2057 is expected to be 20,500 and 14,800MTU for PWR and CANDU spent nuclear fuel, respectively. The quantity of SNF with initial $^{235}U$ enrichment of 4.5 wt.% and below was shown to be 96.5% in total. Average burnup of SNF revealed $\sim36$ GWD/MTU and $\sim40$ GWD/MTU for the period of 1994-1999 and 2000-2003, respectively. It is expected that the average burnup of SNF will be $\sim45$ GWD/MTU at the end of 2000's. From the comprehensive study, it was concluded that the imaginary SNF with $16\times16$ Korean Standard Fuel Assembly, cross section of $21.4cm\times21.4cm$, length of 453cm, mass of 672 kg, initial $^{235}U$ enrichment of 4.5 wt.%, discharge burnup of 55 GWD/MTU could cover almost all SNFs to be produced by 2057.