• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.4
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• pp.21-32
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• 2004

A Seismic analysis procedure of bi-directional brideg motions is developed by using mechanical bridge model. A three-dimensional mechanical model can consider major phenomena under bi-directional seismic excitations, such as nonlinear pier motion under biaxial bending, pounding and bearing damage due to the rotaion of the superstructure, etc. The analyses utilizing the uni-directional and the bi-directional bridge model for the 3-span simply supported bridge are then performed. The seismic responses in two cases are examined and compared by investigating the relative displacements of each superstructure to both ground and adjacent superstructures and the restoring forces of RC pier. The analysis using either the uni-directional model or bi-directional model is acceptable for estimating the displacement responses of a bridge, but the bi-directional analysis is found to give more conservative results for resisting forces of RC piers. To make general conclusions, therefore, the analysis using the bi-directional bridge model should be performed in evaluating the seismic safety of bridges.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.28 no.2
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• pp.89-95
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• 2017

Background and Objectives : High-speed videolaryngoscopy (HSV) is the only technique that captures the true intra-cycle vibratory behavior of the vocal folds by capturing full images of the vocal folds. However, it has problems of no immediate feedback during examination, considerable waiting time for digital kymography (DKG), recording duration limited to a few seconds, and extreme demands for storage space. Herein, we demonstrate a new post-processing method that converts HSV images to two-dimensional digital kymography (2D-DKG) images, which adopts the algorithm of 2D videokymography (2D VKG). Materials and Methods : HSV system was used to capture images of vocal folds. HSV images were post-processed in Kay image-process software (KIPS), and conventional DKG images were retrieved. Custom-made post-processing system was used to convert HSV images to 2D-DKG images. The quantitative parameters of the post-processed 2D-DKG images was validated by comparing these parameters with those of the DKG images. Results : Serial HSV images for all phases of vocal fold vibratory movement are included. The images were converted by the scanning method using U-medical image-process software. Similar to conventional DKG, post-processed 2D DKG image from the HSV image can provide quantitative information on vocal fold mucosa vibration, including the various vibratory phases. Differences in amplitude symmetry index, phase symmetry index, open quotient, and close quotient between 2D-DKG and DKG were analyzed. There were no statistical differences between the quantitative parameters of vocal fold vibratory movement in 2D-DKG and DKG. Conclusion : The post-processing method of converting HSV images to 2D DKG images could provide clinical information and storage economy.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.157-162
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• 2015

Large scale superconducting magnetic energy storage (SMES) system requires very high magnetic energy density in its superconducting coils to enhance the energy capacity and efficiency of the system. The recent high temperature superconducting (HTS) conductors, so called 2G conductors, show very good performance under very high magnetic field so that they seem to be perfect materials for the large scale SMES coils. A general shape of the coil system with the 2G HTS conductor has been a tor oid, because the magnetic field applied perpendicularly to the surface of the 2G HTS conductor could be minimized in this shape of coil. However, a toroid coil requires a 3-dimensional computation to acquire the characteristics of its critical current density - magnetic field relations which needs very complicated numerical calculation, very high computer specification, and long calculation time. In this paper, we suggested an analytic and statistical calculation method to acquire the maximum magnetic flux density applied perpendicularly to the surface of the 2G HTS conductor and the stored energy in the toroid coil system. Although the result with this method includes some errors but we could reduce these errors within 5 percent to get a reasonable estimation of the important parameters for design process of the HTS toroid coil system. As a result, the calculation time by the suggested method could be reduced to 0.1 percent of that by the 3-dimensional numerical calculation.

• Journal of the Korean Chemical Society
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• v.40 no.3
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• pp.161-166
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• 1996

6-ethyl-5,6-dihydrouracil($C_6H_10N_2O_2$) is monoclinic, space group $$P2_{1}c}$$ with a=10.302(2), b=10.419(3), $c=7.095(1)\AA$, $\beta=106.6(0)$, Z=4, $V=729.7(3)\AA$^3$$, $D_c=1.29 g/cm^3,\;{\lambda}(MoK\alpha)=0.71073\AA$, $\mu=0.010cm^{-1}$, F(000)=304, and R=0.054 for 1070 unique observed reflection with F>4.0 $\sigma(F).$ The structure was solved by direct methods and refined by full-matrix least-squares refinement with the fixed C-H bond length at $0.96\AA.$ The hydrouracil molecule makes an envelope conformation with the ethyl substituent oriented to an axial position attainable to a varying degree of steric strain. There are two intermolecular hydrogen-bondings via N-H---O interactions, being nearly parallel to the 100 plane. The shortest distance between molecules is $3.187\AA$ of C(4) and O(8) (-x,-y, 1-z).

• The korean journal of orthodontics
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• v.40 no.3
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• pp.145-155
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• 2010

Objective: Lateral cephalometric radiographs have been the main form of resource for assessing two dimensional anteroposterior airway changes. The purpose of this study was to evaluate the three dimensional volumetric change in the upper airway space in Class III malocclusion patients who underwent mandibular setback surgery. Methods: Three dimensional cone-beam computed tomographs (CBCT) and their three dimensional reconstruction images were analyzed. The samples consisted of 20 adult patients (12 males and 8 females) who were diagnosed as skeletal Class III and underwent mandibular setback surgery. CBCTs were taken at 3 stages - Baseline (1.8 weeks before surgery), T1 (2.3 months after surgery), and T2 (1 year after surgery). Pharyngeal airway was separated according to the reference planes and reconstructed into the nasopharynx, the oropharynx and the hypopharynx. Measurements at Baseline, T1, and T2 were compared between groups. Results: The result showed the volume of the pharyngeal airway decreased significantly 2.3 months after surgery (p < 0.001) and the diminished airway did not recover after 1 year post-surgery. The oropharynx was the most decreased area. Conclusions: These findings suggest that mandibular setback surgery causes both short-term and long-term decrease in the upper airway space.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.249-260
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• 2007

Purpose: In order to enhance the quality of IMRT as employed in Korea, we developed a remote monitoring system. The feasibility of the system was evaluated by conducting a pilot study. Materials and Methods: The remote monitoring system consisted of a head and neck phantom and a user manual. The phantom contains a target and three OARs (organs at risk) that can be detected on CT images. TLD capsules were inserted at the center of the target and at the OARs. Two film slits for GafchromicEBT film were located on the axial and saggital planes. The user manual contained an IMRT planning guide and instructions for IMRT planning and the delivery process. After the manual and phantom were sent to four institutions, IMRT was planed and delivered. Predicted doses were compared with measured doses. Dose distribution along the two straight lines that intersected at the center of the axial film was measured and compared with the profiles predicted by the plan. Results: The measurements at the target agreed with the predicted dose within a 3% deviation. Doses at the OARs that represented the thyroid glands showed larger deviations (minimum 3.3% and maximum 19.8%). The deviation at OARs that represented the spiral cord was $0.7{\sim}1.4%$. The percentage of dose distributions that showed more than a 5% of deviation on the lines was $7{\sim}27%$ and $7{\sim}14%$ along the horizontal and vertical lines, respectively. Conculsion: Remote monitoring of IMRT using the developed system was feasible. With remote monitoring, the deviation at the target is expected to be small while the deviation at the OARs can be very large. Therefore, a method that is able to investigate the cause of a large deviation needs to be developed. In addition, a more clinically relevant measure for the two-dimensional dose comparison and pass/fail criteria need to be further developed.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.218-222
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• 2014

In this paper, we introduce an autonomous calibration method for a 2D laser displacement sensor (e.g. laser vision sensor and laser range finder) by matching a single point on a flat structure. Many arc welding robots install a 2D laser displacement sensor to expand their application by recognizing their environment (e.g. base metal and seam). In such systems, sensing data should be transformed to the robot's coordinates, and the geometric relation (i.e. rotation and translation) between the robot's coordinates and sensor coordinates should be known for the transformation. Calibration means the inference process of geometric relation between the sensor and robot. Generally, the matching of more than 3 points is required to infer the geometric relation. However, we introduce a novel method to calibrate using only 1 point matching and use a specific flat structure (i.e. circular hole) which enables us to find the geometric relation with a single point matching. We make the rotation component of the calibration results as a constant to use only a single point by moving a robot to a specific pose. The flat structure can be installed easily in a manufacturing site, because the structure does not have a volume (i.e. almost 2D structure). The calibration process is fully autonomous and does not need any manual operation. A robot which installed the sensor moves to the specific pose by sensing features of the circular hole such as length of chord and center position of the chord. We show the precision of the proposed method by performing repetitive experiments in various situations. Furthermore, we applied the result of the proposed method to sensor based seam tracking with a robot, and report the difference of the robot's TCP (Tool Center Point) trajectory. This experiment shows that the proposed method ensures precision.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.283-293
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• 2002

Purpose : A PC based brachytherapy planning system was developed to display dose distributions on simulation images by 2D isodose curve including the dose profiles, dose-volume histogram and 30 dose distributions. Materials and Methods : Brachytherapy dose planning software was developed especially for the Ir-192 source, which had been developed by KAERI as a substitute for the Co-60 source. The dose computation was achieved by searching for a pre-computed dose matrix which was tabulated as a function of radial and axial distance from a source. In the computation process, the effects of the tissue scattering correction factor and anisotropic dose distributions were included. The computed dose distributions were displayed in 2D film image including the profile dose, 3D isodose curves with wire frame forms and dosevolume histogram. Results : The brachytherapy dose plan was initiated by obtaining source positions on the principal plane of the source axis. The dose distributions in tissue were computed on a $200\times200\;(mm^2)$ plane on which the source axis was located at the center of the plane. The point doses along the longitudinal axis of the source were $4.5\~9.0\%$ smaller than those on the radial axis of the plane, due to the anisotropy created by the cylindrical shape of the source. When compared to manual calculation, the point doses showed $1\~5\%$ discrepancies from the benchmarking plan. The 2D dose distributions of different planes were matched to the same administered isodose level in order to analyze the shape of the optimized dose level. The accumulated dose-volume histogram, displayed as a function of the percentage volume of administered minimum dose level, was used to guide the volume analysis. Conclusion : This study evaluated the developed computerized dose planning system of brachytherapy. The dose distribution was displayed on the coronal, sagittal and axial planes with the dose histogram. The accumulated DVH and 3D dose distributions provided by the developed system may be useful tools for dose analysis in comparison with orthogonal dose planning.

• The korean journal of orthodontics
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• v.39 no.3
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• pp.136-145
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• 2009

Objective: CBCT has become popular for orthodontic diagnosis and treatment planning in recent times. The 3D pharyngeal airway space needs to be analysed using a 3D diagnostic tool. The aim of this study was to analyse the pharyngeal airway of different craniofacial morphology using CBCT. Methods: The sample compromised 102 subjects divided into 3 groups (Class I, II, III) and 6 subgroups according to normal or vertical craniofacial patterns. All samples had CBCT (VCT, Vatech, Seoul, Korea) taken for orthodontic treatment. The pharyngeal airway was assessed according to the reference planes: aa plane (the most anterior point on the anterior arch of atlas), $CV_2$ plane, and $CV_3$ plane (most infero-anterior point on the body of the second & third cervical vertebra). The intergroup comparison was performed with one-way ANOVA and duncan test as a second step. Results: The results showed the pharyngeal airway and anteroposterior width of group 2 (Class II) in aa plane, $CV_2$ plane, $CV_3$ plane were significant narrower than in group 3 (Class III). There was no significant difference between vertical and normal craniofacial patterns except for the anteroposterior pharyngeal width of Group 1 (Class I) in aa plane. Conclusions: Subjects with Class II patterns have a significantly narrower pharyngeal airway than those with Class III. However there was no difference in pharyngeal airway between vertical and normal craniofacial morphology.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.117-124
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• 2007

This paper describes methodology that enables animators to create the facial expression animations and to control the facial expressions in real-time by reusing motion capture datas. In order to achieve this, we fix a facial expression state expression method to express facial states based on facial motion data. In addition, by distributing facial expressions into intuitive space using LLE algorithm, it is possible to create the animations or to control the expressions in real-time from facial expression space using user interface. In this paper, approximately 2400 facial expression frames are used to generate facial expression space. In addition, by navigating facial expression space projected on the 2-dimensional plane, it is possible to create the animations or to control the expressions of 3-dimensional avatars in real-time by selecting a series of expressions from facial expression space. In order to distribute approximately 2400 facial expression data into intuitional space, there is need to represents the state of each expressions from facial expression frames. In order to achieve this, the distance matrix that presents the distances between pairs of feature points on the faces, is used. In order to distribute this datas, LLE algorithm is used for visualization in 2-dimensional plane. Animators are told to control facial expressions or to create animations when using the user interface of this system. This paper evaluates the results of the experiment.