• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.13-20
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• 2010

Currently, NGII(National Geographic Information Institute) provides VRS(Virtual Reference System) service using 44 CORS(Continuously Operating Reference Stations). Since the VRS provides high-precision coordinate in a short time, the users and applications are expected to be rapidly increasing. The accuracy analysis on the VRS service, however, was not sufficiently performed yet. Therefore, in this study, the VRS data is acquired from various circumstances and its accuracy is analyzed. According to analysis, it was concluded that the VRS could be applied to public control point survey. Furthermore, it was found that the PQ(Position Quality) which represents variance of estimated coordinates rather than GDOP(Geometric Dilution of Precision) is more relevant as a factor to determine the accuracy of coordinates. Based on the analysis of data from four manufacturers (TRIMBLE, MAGELLAN, LECIA, TOPCON), it was confirmed that the standard deviations better than 3cm. Therefore, VRS Survey apply to public control point survey.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.5
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• pp.385-394
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• 2012

A computer program that can estimate static, dynamic stability and control derivatives using a subsonic-supersonic panel method is developed. The panel method uses subsonic-supersonic source and elementary horse shoe vortex distributions, and their strengths are determined by solving the boundary condition approximated with a thin body assumption. In addition, quasi-steady analysis on the body fixed coordinate system allows the estimation of damping coefficients of aircraft 3 axes. The code is validated by comparing the neutral point, roll and pitch damping of delta wings with published analysis results. Finally, the static, dynamic stability and control derivatives of F-18 are compared with experimental data as well as other numerical results to show the accuracy and the usefulness of the code.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1094-1104
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• 2010

In the previous studies, the validation of numerical codes has been conducted based on the qualitative comparison of predicted ice shapes with experiments, which poses a significant limit on the systematic analysis of ice shapes due to the variation of meteorological conditions. In response to this, the numerical code has been quantitatively validated against available experiment for the ice accretion on cylinders and airfoils in the present study. Ice shapes accumulated on the bodies are systematically investigated with respect to various icing parameters. To this end, maximum thickness, heading direction and ice thickness are quantified and expressed in the polar coordinate system for the comparison with other numerical results. By applying the quantitative analysis, similar shapes are intuitively distinguished. The developed numerical code underestimates the ice accretion area and the ice thickness of lower surface. In order to improve the accuracy, further accurate aerodynamic solver is required for the water droplet trajectories.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.1007-1016
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• 2005

This paper presents a feature extraction method for shape based retrieval of 3D models. Since the feature descriptor of 3D model should be invariant to translation, rotation and scaling, it is necessary to preprocess the 3D models to represent them in a canonical coordinate system. We use the PCA(Principal Component Analysis) method to preprocess the 3D models. Also, we apply that to make a MBR(Minimum Boundary Rectangle) and a circumsphere. The proposed algorithm is as follows. We generate a circumsphere around 3D models, where radius equals 1(r=1) and locate each model in the center of the circumsphere. We produce the concentric spheres with a different radius($r_i=i/n,\;i=1,2,{\ldots},n$). After looking for meshes intersected with the concentric spheres, we compute the curvature of the meshes. We use these curvatures as the model descriptor. Experimental results numerically show the performance improvement of proposed algorithm from min. 0.1 to max. 0.6 in comparison with conventional methods by ANMRR, although our method uses .relatively small bins. This paper uses $R{^*}-tree$ as the indexing.

• Journal of the Korean Ceramic Society
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• v.55 no.4
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• pp.368-375
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• 2018

This study deals with the color formation of ceramic pigment in the $TiO_2$-SnO-ZnO system. We designed compounds to control the color formation depending on the composition using the Design of Experiment. The color coordinate values of synthesized pigments, $L^*a^*b^*$ were measured and statistically analyzed color for changing elements depending on its composition. The relationship between the major crystalline phases and chromaticity was examined using XRD, and the oxidation states of each element were analyzed by XPS. The synthesized pigments based on the compound design exhibited various color changes ranging from yellow-orange to green-blue and brown. The statistical analysis on the spectrophotometer results shows that $a^*$ and $b^*$ values decreased with $TiO_2$ content, and increased with SnO content. Yellow-orange color was detected with the main peak of SnO, and the green-blue color developed with the main peak of $Zn_2TiO_4$. The $a^*$ and $b^*$ values increased with increased SnO peak intensity, and decreased with increased $Zn_2TiO_4$ peak intensity. The results revealed that pigment color formation was influenced by changes in the main crystalline phases and crystalline intensity. However, XPS analysis of the oxidation states of each element showed little correlation with the pigment chromaticity result.

• Hwankyungkyoyuk
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• v.13 no.2
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• pp.51-62
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• 2000

This study examined the current status of school environmental education (EE) in Germany, and attempted to propose strategies to develop school EE in Korea. The study intended to accomplish the following goals: First, this study attempted to examine the developmental process of school EE in Germany. Second, exemplary cases of site-based experiential education in Germany are selected and analysed to develop pedagogical strategies in school EE in Korea. The strategies for development proposed in this study can be summarized as follows: First, the focus of EE should go beyond that of "solving or curing"environmental problems and pollutions, and need to be re-directed to pursue an "education for sustainable development", a new paradigm for future EE. Second, EE should increasingly integrate outdoor site-based, experiential programs into the currently classroom-based and knowledge-driven forms of education, not only to maximize its educational effect but also and knowledge-driven forms of education, not only to maximize its educational effect but also to coordinate the instruction of EE in the context of the educational reform agenda, currently undergoing since the late 1990s, in Korea. Third, teaching-learning materials for EE should be variously developed, and programs should be encouraged to serve local needs and circumstances for effective classroom practices, and criteria for standardization and professionalization should be sought in developing these programs. Fourth, it is recommended that the Ministry of Environment secure funds to facilitate the local school authorities at the municipal and provincial levels to operate a mobile environmental support system, equivalent to the function of the "Lumbricus"in Germany. Fifth, an external support network should be established among the support agencies for EE. Especially, a professional agency or institute to academically support school EE and a special planning committee for enhancing EE need to be established for resource and personal development. Parents′voluntary participation should also be encouraged to establish a tripartite network of "school-community-government" to support and facilitate school EE.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.521-529
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• 2002

We have recently proposed the new concept of a phase-measuring volumetric interferometer that enables us to accurately measure the xyz-coordinates of the probe without metrology frames. The interferometer is composed of a movable target and a fixed photo-detector array. The target is made of point diffraction sources to emit two spherical wavefronts, whose interference is monitored by an array of photo-detectors. Phase shifting is applied to obtain the precise phase values of the photo-detectors. Then the measured phases are fitted to a geometric model of multilateration so as to determine the xyz-location of the target by minimizing least square errors. The proposed interferometer has been designed and built with a volumetric uncertainty of less than 1.0 $\mu\textrm{m}$ within a cubic working volume of side 120 mm. Here, in this paper, we also present error sources, an evaluated uncertainty, and test results from the prototype system. The self-calibration of two-dimensional precision metrology stages is applied to test the performance of the interferometer.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1479-1485
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• 2008

This paper shows the result of study on the detailed applicable procedure of software Escrow account applied for rolling stock. The customer as end-user requires software source code, related critical technical documents etc. about software based system of train for maintenance purpose through software modification and enhancement after completion of warranty period. Otherwise, it is not easy to keep up with the customer's requirement of demanding supplier's exclusive information because it is considered as intellectual property rights of supplier as software developer. Therefore, the main contractor(normally called as Car-builder) need to introduce software Escrow service in order to coordinate the different a standpoint between software developer and end-user. Software Escrow is a legal arrangement in which an software Escrow packages (software source code, software development tool, build process, proprietary information, copyright and etc.) is deposited into and Escrow account under the trust of a reliable third party (Escrow agent) depending on mutual agreement on Escrow contract condition as signing off Escrow agreement document. This paper deals with the study on the detailed procedure about the following general category of Escrow procedure and purpose to apply this specific procedure of Escrow into the future project onward.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.2
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• pp.71-78
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• 2018

This paper presents the assembling of multiple patches based on the single patch isogeometric formulation for the shear deformable shell element given in the previous study. The geometrically exact shell formulation has been accomplished with the shell theory based formulation and the generalized curvilinear coordinate system directly derived from the given NURBS geometry. For the knot elements matching across adjacent surfaces, the zero-th and first parametric continuity conditions are considered and the corresponding coupling constraints are implemented by a master-slave formulation between adjacent patches. The constraints are then enforced by a substitution method for condensation of the slave variables, thereby reducing the model size. Through numerical investigations, the important features of the first parametric continuity condition are confirmed. The performance of the multi-patch shell models is also examined comparing the rate of convergence of response coefficients for the zero and first order continuity conditions and continuity in coupling boundary between two patches is confirmed.

• Journal of KIISE
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• v.43 no.4
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• pp.437-449
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• 2016

Previous image processing techniques based on plane-to-plane transformations cannot be utilized for spherical panoramic images. In this paper, we propose a new method to inpaint a spherical panoramic image using exemplar, which is deformed by the location of the patch. Our proposed method makes the deformed exemplar patch by latitude and uses it as the reference patch to restore the damaged area. The exemplar-based inpainting method is based on the planar image coordinate system and thus the classical method cannot be applied to the spherical panoramic image. The merit of our proposed method is the fact that it is not dependent on the location of the damaged area. From the experimental results, we proved that our proposed method satisfies the original purpose of the exemplar-based inpainting technique for the spherical panoramic image.