• Journal of Broadcast Engineering
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• v.18 no.1
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• pp.31-42
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• 2013

This paper proposes a photogrammetric rectification method based on Bayesian approach as a method that eliminates vertical parallax between stereo images to minimize visual fatigue of 3D contents. The image rectification consists of two phases; geometry estimation and epipolar transformation. For geometry estimation, coplanarity-based relative orientation algorithm was used in this paper. To ensure robustness for mismatch and localization error occurred by automation of tie point extraction, Bayesian approach was applied by introducing several prior constraints. As epipolar transformation perspective transformation was used based on condition of collinearity to minimize distortion of result images and modification for input images. Other algorithms were compared to evaluate performance. For geometry estimation, traditional relative orientation algorithm, 8-points algorithm and stereo calibration algorithm were employed. For epipolar transformation, Hartley algorithm and Bouguet algorithm were employed. The evaluation results showed that the proposed algorithm produced results with high accuracy, robustness about error sources and minimum image modification.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.829-834
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• 2009

A ballast-flying probabilitie is suggested for various ballast types, heighter types and underbody flow conditions as train speeds. The average speed of measured points is converted to the ballast-flying probabilities of BFPF which come from wind tunnel test data. Underbody flow fields are numerically simulated for the various conditions. The results show that the ballast-flying probability is steeply increased as train speed increased, and reaches a value of 87% at 350 km/h train speed. And the differences of probabilities among the ballast shapes are considerably high. The upper surface of heighter or tie is most probable area. Through this study, the ballast-flying Sensitivities with heighter was defined to understand the characteristics of ballast-flying probability on various conditions. And the ballast-flying probability can be reduced by the heighter.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.281-288
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• 2009

In the paper, we try to develop the methodology for updating road networks of large-scale digital maps by using construction drawing data. For the purpose, it is pre-requite step to merge road networks detached in CAD drawing data. As such, tie points are identified in neighboring drawings and used for solving the parameters of 2D conformal transformation between drawings. Then, the merged road network in CAD data is transformed to the coordinate system of digital maps. In the process, IPs in the drawings are considered as control information and 2D affine transformation is selected for coordinate transformation. Through the experiments with real dataset, we can identify that the developed method is valid and generally applicable.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.1
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• pp.27-34
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• 2011

Purpose: To evaluate the short term clinical result of ACL reconstruction with autologous hamstring tendon using Cross pin and Graft Tensioner and to seek way to resolve the experienced technical problems. Materials and Methods: From January 2008 to March 2009, 35 patients who had been treated arthroscopic ACL reconstruction were enrolled. The femoral side of ACL graft was fixed with Cross pin. The tibial side of graft was fixed with Intrafix and post-tie. The graft was tensioned with Graft Tensioner at 80N. We analyzed the clinical, radiographic results and complications. Results: IKDC subjective score and Lysholm score improved to 89.1 and 91.4 points. Also, Pivot shift test and One-leg hop test showed good results postoperatively. Side to side difference using KT-1000 arthrometer and Telos stress radiography improved compared with normal limb to $2.8{\pm}1.6$ mm and $2.6{\pm}1.3$ mm, respectively. The femoral tunnel enlarged to $2.3{\pm}1.1$ mm. Soft tissue irritation and femoral tunnel-graft harness length mismatch, femoral tunnel-cross pin tunnel mismatch were happened as peri-operative complications. Conclusion: Using of Cross pin and Graft Tensioner for ACL reconstruction with hamstring tendon is one of the good method for obtaining stability in short-term clinical result. But to reduce femoral tunnel-cross pin mismatch, it needs to shorten femoral bone tunnel and to create cross pin tunnel as vertical as possible. And to reduce femoral tunnel-graft harness mismatch, it needs to advance position rod further 3 mm when to create femoral tunnel.

• Korean Journal of Construction Engineering and Management
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• v.17 no.3
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• pp.32-42
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• 2016

In Korea, the absence of BIM use in existing civil structures and buildings is driving a demand for as-built BIM. As-built BIMs are often created using laser scanners that provide dense 3D point cloud data. Conventional static laser scanning approaches often suffer from limitations in their operability due to the difficulties in moving the equipment, the selection of scanning location, and the requirement of placing targets or extracting tie points for registration of each scanned point cloud. This paper aims at reducing the manual effort using a kinematic 3D laser scanning system based on graph-based simultaneous localization and mapping (SLAM) for continuous indoor mapping. The robotic platform carries three 2D laser scanners: the front scanner is mounted horizontally to compute the robot's trajectory and to build the SLAM graph; the other two scanners are mounted vertically to scan the profiles of surrounding environments. To reduce the accumulated error in the trajectory of the platform through loop closures, the graph-based SLAM system incorporates AdaBoost loop closure approach, which is particularly suitable for the developed multi-scanner system providing more features than the single-scanner system for training. We implemented the proposed method and evaluated it in two indoor test sites. Our experimental results show that the false positive rate was reduced by 13.6% and 7.9% for the two dataset. Finally, the 2D and 3D mapping results of the two test sites confirmed the effectiveness of the proposed graph-based SLAM.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.411-421
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• 2012

The stagnant growth in 3D market due to 3D movie contents shortage is encouraging development of techniques for production cost reduction. Elimination of vertical disparity generated during image acquisition requires heaviest time and effort in the whole stereoscopic film-making process. This matter is directly related to competitiveness in the market and is being dealt with as a very important task. The removal of vertical disparity, i.e. image rectification has been treated for a long time in the photogrammetry field. While computer vision methods are focused on fast processing and automation, photogrammetry methods on accuracy and precision. However, photogrammetric approaches have not been tried for the 3D film-making. In this paper, proposed is a photogrammetry-based rectification algorithm that enable to eliminate the vertical disparity precisely by reconstruction of geometric relationship at the time of shooting. Evaluation of proposed algorithm was carried out by comparing the performance with two existing computer vision algorithms. The epipolar constraint satisfaction, epipolar line accuracy and vertical disparity of result images were tested. As a result, the proposed algorithm showed excellent performance than the other algorithms in term of accuracy and precision, and also revealed robustness about position error of tie-points.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10879-10882
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• 2015

Objective: To investigate the effect of intraoperative glucose fluctuation and postoperative interlukin-6 (IL-6), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), C-reactive protein (CRP) levels on the short-term prognosis of patients with intracranial supratentorial neoplasms. Materials and Methods: Eighty-six patients undergoing intracranial excision were selected in The Second Hospital of Jilin University. According to the condition of glucose fluctuation, the patients were divided into group A (glucose fluctuation <2.2 mmol/L, n=57) and group B (glucose fluctuation ${\geq}2.2mmol/L$, n=29). Glucose was assessed by drawing 2 mL blood from internal jugular vein in two groups in the following time points, namely fasting blood glucose 1 d before operation ($T_0$), 5 min after anesthesia induction ($T_1$), intraoperative peak glucose ($T_2$), intraoperative lowest glucose ($T_3$), 5 min after closing the skull ($T_4$), immediately after returning to intensive care unit (ICU) ($T_5$) and 2 h after returning to ICU ($T_6$). 1 d before operation and 1, 3 and 6 d after operation, serum IL-6 and TNF-${\alpha}$ levels were detected with enzyme-linked immunosorbent assay (ELISA), and CRP level with immunoturbidimetry. Additionally, postoperative adverse reactions were monitored. Results: There was no statistical significance between two groups regarding the operation time, anesthesia time, amount of intraoperative bleeding and blood transfusion (P>0.05). The glucose levels in both groups at $T_1{\sim}T_6$ went up conspicuously compared with that at $T_0$ (P<0.01), and those in group B at $T_2$, $T_4$, $T_5$ and $T_6$ were significantly higher than in group A (P<0.01). Serum IL-6, TNF-${\alpha}$ and CRP levels in both groups 1, 3 and 6 d after operation increased markedly compared with 1 d before operation (P<0.01), but the increased range in group A was notably lower than in group B (P<0.05 or P<0.01). Postoperative incidences of hypoglycemia, hyperglycemia and myocardial ischemia in group A were significantly lower than in group B (P<0.05), and respiratory support time obviously shorter than in group B (P<0.01). Conclusions: The glucose fluctuation of patients undergoing intracranial excision is related to postoperative IL-6, TNF-${\alpha}$ and CRP levels and those with small range of glucose fluctuation have better prognosis.