• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.9
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• pp.467-473
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• 2002

In this paper, a fault location algorithm is suggested for line to line faults in distribution networks. Conventional fault location algorithms use the symmetrical component transformation, a very useful tool for transmission network analysis. However, its application is restricted to balanced network only. Distribution networks are, in general, operated in unbalanced manners, therefore, conventional methods cannot be applied directly, which is the reason why there are few research results on fault location in distribution networks. Especially, the line to line fault is considered as a more difficult subject. The proposed algorithm uses direct 3-phase circuit analysis, which means it can be applied not only to balanced networks but also to unbalanced networks like distribution a network. The comparisons of simulation results between one of conventional methods and the suggested method are presented to show its effectiveness and accuracy.

• Korean Journal of Computational Design and Engineering
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• v.5 no.3
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• pp.276-284
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• 2000

Usual practice of the transformation of a B-spline curve into a set of piecewise polynomial curves in a power form is done by either a knot refinement followed by basis conversions or applying a Taylor expansion on the B-spline curve for each knot span. Presented in this paper is a new algorithm, called a direct expansion algorithm, for the problem. The algorithm first locates the coefficients of all the linear terms that make up the basis functions in a knot span, and then the algorithm directly obtains the power form representation of basis functions by expanding the summation of products of appropriate linear terms. Then, a polynomial segment of a knot span can be easily obtained by the summation of products of the basis functions within the knot span with corresponding control points. Repeating this operation for each knot span, all of the polynomials of the B-spline curve can be transformed into a power form. The algorithm has been applied to both static and dynamic curves. It turns out that the proposed algorithm outperforms the existing algorithms for the conversion for both types of curves. Especially, the proposed algorithm shows significantly fast performance for the dynamic curves.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.182-185
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• 2005

Satellite cameras are calibrated before launch in detail and in general, but it cannot be guaranteed that the geometry is not changing during launch and caused by thermal influence of the sun in the orbit. Modem satellite imaging systems are based on CCD-line sensors. Because of the required high sampling rate the length of used CCD-lines is limited. For reaching a sufficient swath width, some CCD-lines are combined to a longer virtual CCD-line. The images generated by the individual CCD-lines do overlap slightly and so they can be shifted in x- and y-direction in relation to a chosen reference image just based on tie points. For the alignment and difference in scale, control points are required. The resulting virtual image has only negligible errors in areas with very large difference in height caused by the difference in the location of the projection centers. Color images can be related to the joint panchromatic scenes just based on tie points. Pan-sharpened images may show only small color shifts in very mountainous areas and for moving objects. The direct sensor orientation has to be calibrated based on control points. Discrepancies in horizontal shift can only be separated from attitude discrepancies with a good three-dimensional control point distribution. For such a calibration a program based on geometric reconstruction of the sensor orientation is required. The approximations by 3D-affine transformation or direct linear transformation (DL n cannot be used. These methods do have also disadvantages for standard sensor orientation. The image orientation by geometric reconstruction can be improved by self calibration with additional parameters for the analysis and compensation of remaining systematic effects for example caused by a not linear CCD-line. The determined sensor geometry can be used for the generation? of rational polynomial coefficients, describing the sensor geometry by relations of polynomials of the ground coordinates X, Y and Z.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1207-1210
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• 2004

As many humans age, degenerative lumbar spinal stenosis (DLSS) becomes a major cause of lower limb discomfort and disability. By surgical treatment method of DLSS, the existing surgical treatment methods using internal fixation have showed degeneration changes of an adjacent vertebrae and loss of lumbar spine lordosis-kyphosis due to eliminating a motion. For solving the problems of internal fixation, a novel interspinous spacer has been developed to treat DLSS by surgical treatment method. In this study, we evaluated the biomechanical effects of the interspinous spacer on the kinematics of the porcine lumbar spine before and after insertion of the implant. For this purpose, a device that is capable of measuring 3-D motions were built based on direct linear transformation (DLT) algorithm written with MATLAB program. Results showed that in extension, a change of the mean angle between the intact and the implanted specimens at L4-L5 was 1.87 degree difference and the implant reduced the extension range of motion of the L4-L5 (p＆lt;0.05). But the range of motion in flexion, axial rotation and lateral bending at the adjacent segments was not statistically affected by the implant. In conclusion, we thought that interspinous spacer may have remedical value for DLSS by flexing human lumbar spine.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.8-17
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• 2012

In this paper we proposes a new framework to obtain 3D shape information of thin film rapidly. The conventional equipments based on reflectometry are not suitable for obtaining 3D overall shape information of thin film rapidly since they require more than 30 minutes to measure the absolute thickness for 170 points. The proposed framework is based on an image analysis method that extracts contour lines from interference fringes images using Canny edge detector. The absolute thickness for contour lines are measured and then a height map from the contour lines is obtained by interpolation using Borgefors distance transformation. The extracted height map is visualized using the DirectX 3D terrain rendering method. The proposed framework can provide 3D overall shape information of thin film in about 5 minutes since relatively small number of real measurement for contour lines is required.

• Korean Journal of Remote Sensing
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• v.16 no.1
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• pp.73-86
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• 2000

Commonly-used methods for camera modelling of pushbroom images were implemented and their performances were assessed. The models include Vector Propagation) model, Gugan and Downman(GD)'s model, Orun and Natarajan(ON)'s model, and Direct Linear Transformation(DLT) model The models were tested on a SPOT full-scene over Seoul. The number of ground control points(GCP) used range from 1 to 23. For less than 6 GCPs all other models fail except VP, with VP's accuracy being 2.7 pixels. With mode than 6 GCPs ON shows the best accuracy with 1pixel accuracy while the accuracy of VP is 1.5 pixels. GD fails in most cases due to the correlation among model parameters. The accuracy of DLT does not converge but fluctuates between 1 and 4 pixels subject to GCPs used. VP has an advantage in that its results can be used for the estimation of satellite orbit. Unresolved topics are: to remove errors in GCPs from the aforementioned accuracy value; to improve the performance of VP.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.2
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• pp.152-162
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• 2008

This paper presents a sliding mode controller (SMC) to directly control the active and reactive powers of a doubly ffd induction generator (DFIG) for wind turbines. Sliding-mode control (SMC) and space-vector modulation (SVM) are combined to ensure high-performance operation. SMC scheme is designed to provide robust and fast power controls without frame transformation and current controller used in the conventional FOC drive. Simulation results and experimental results demonstrate that proposed methods preserve the effectiveness and robustness during variations of active and reactive power.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.7 no.1
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• pp.103-146
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• 1994

Koryokukshinjodaechangkyochongbyollock is an epoch-making catalogue for historical study of proofing Buddhist scriptures in Korea. This bibliography was appended to the 30 volumes which was corrected in 70 Ham, 66 scriptures, and 79 cases. Comparing the differences between the first carved Tripitaka' s texts in Korea, texts made in the Sung dynasty, and the Kitan's texts, this catalogue discovered the name of scriptures, translators, volume number, the changed am order as well as omission, defaults, mistranslation of the Tripitaka made in the Sung dynasty. From Chon-ham to Young-ham, 480 sets among Kaewon-sokkyorock and 43 sets among Chongwonrock were correctly laid. Songshinyokkyong and the Sung Emperor, T'ai Tsung's statements were excluded. Even though it was possible to get these scriptures only by import from Sung, these imported scriptures had no reason to be proofed because of their new version and the author's direct selection in Sung. Shinchipchangkyon-geumeuisuhamlock has no authentic Sung's and Koryo's text books for correction. kyochongbyollock delivered the scriptures listed on Kudaechangmoklock, which gives an important clue to research transformation from the first to the second carved Tripitaka. Through the systematic study of the transformated facts beteween the first carved Tripitaka and the second one, This study would help rebulid the original Chojodaechan-gkynng which has been not yet perfectly discovered itself.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.5
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• pp.375-379
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• 2001

Transgenic plants from hypocotyl segments of buckwheat were produced with the Agrobacterium strain LBA4404 harboring the binary vector pBI121 containing chimeric genes of neomycin phosphotransferase II (npt II) and $\beta$-glucuronidase (gus). Two weeks after co-cultivation with Agrobacterium, most of the hypocotyl segments gradually became brown and died on the selection medium containing 100mg/$\ell$ of kanamycin. Plants regenerated from the hypocotyl explants grown on selection medium were GUS-positive in the leaf, stem and vascular tissues by histochemical assay, and varied in gus activity (440-2568 pmol, 4-MU/mg protein) by fluorimetry. The plants showing GUS activity were confirmed of containing GUS and NPT-II genes by polymerase chain reaction (PCR). Within 3 months, transgenic buckwheat plants were able to obtained from the hypocotyl segments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.285-286
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• 2006

The essential tasks to operate the welding robot are the acquisition of the position and/or shape of the parent metal. For the seam tracking or the robot automation, many kinds of contact and non-contact sensors are used. Recently, the vision sensor is most popular. In this paper, the development of the system which measures the profile of the welding part is described. The total system will be assembled into a compact module which can be attached to the head of welding robot system. This system uses the line-type structured laser diode and the vision sensor It implemented Direct Linear Transformation (DLT) for the camera calibration as well as radial distortion correction. The three dimensional shape of the parent metal is obtained after simple linear transformation and therefore, the system operates in real time. Some experiments are carried out to evaluate the performance of the developed system.