• Current Optics and Photonics
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• v.3 no.5
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• pp.451-457
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• 2019

Laser processing using holograms can greatly improve processing speed, by spatially distributing the laser energy on the target material. However, it is difficult to reconstruct an image with arrays of closely spaced spots for laser processing, because the specklelike interference pattern prevents the spots from getting close to each other. To resolve this problem, a line target was divided in two, reconstructed with orthogonally polarized beams, and then superposed. Their optical reconstruction was performed by computer-generated holograms and a pulsed laser. With this method, we performed two-dimensional (2D) laser drilling of polyimide film, with a kerf width of $20{\mu}m$ and a total processing length of 20 mm.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.111-116
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• 2011

Consumers demand an increasing variety of requirements for the residential space as the quality of life improves. However, many apartment buildings with the bearing wall structure cannot meet such demands in Korea. A lot of construction resources are squandered and wastes are created as this type of residential buildings is reconstructed. The life of apartment buildings needs to be extended on the basis of easy remodeling of internal space in order to overcome the limits of the bearing wall structure. This research project aims to propose the Rahmen composite frame concept for the long life of apartment buildings. The Rahmen composite frame is expected to have better structural performance, constructability and economic feasibility than the bearing wall structure.

• Journal of The Korea Institute of Healthcare Architecture
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• v.27 no.2
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• pp.15-24
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• 2021

Purpose: This study is to present basic data on the Architectural planning of the college of medicine by arranging the functional zoning planning, functional unit planning, and circulation planning, based on the diversification of medical education and the changes of Learning spaces. Methods: This study was conducted by literature review on existing medical education method and learning space planning. And then on-site surveys and questionnaire were conducted on existing facilities. Results: The diversification of medical education has already been progressing for a long time, and the development of information technology is integrated into the learning space, and the evolution of the learning method and the flexibility of the learning space give effect to the change of the learning space. ① This study reconstructed the existing classification method of university facilities into the fuctional zoning method that combines the architectural concept of function and movement. ② The functions and functional units of the college of medicine according to the proposed functional zone were arranged, and the space required for the medical college was suggested. ③ The function and type of movement of medical college can be classified into professor/student fusion type, teaching and research separation type, and learning and learning shared space integrated arrangement type. In the future, it is necessary to consider fusion type or integrated arrangement type rather than separation type. Implications: the evolution of the learning method and the flexibility of the learning space give effect to the change of the learning space.

• Imaging Science in Dentistry
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• v.47 no.3
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• pp.199-207
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• 2017

Purpose: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Materials and Methods: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Results: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Conclusion: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

• Journal of Astronomy and Space Sciences
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• v.25 no.3
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• pp.299-320
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• 2008

We study on the astronomical calendars that was used in the Silla era. The calendars are deduced from the records in Samguksagi. They were influenced from calendaric system of Tang Dynasty, which are Lin duk calendar(麟德曆), Ta yen calendar(大衍曆) and Sun myung calendar(宣明曆). We analyse them in detail according to the time and duration of use. Water clock system of Unified Silla was used four water vessels for supplying water. We found the model from documents on ancient water clock that are appeared in the old Korean, Chinese and Japanese historical records. We have assumed the model of Unified Silla clepsydra is similar type with Chinese records during Tang dynasty and with Japanese reconstructed water clock in Temple Asoka. After fluid dynamic experiment, we decide the suitable diameter of supplying pipe and volume of the vessels used in the clepsydra. We introduce the experimental instruments and methods for accomplishing the clock. We designed and reconstructed the water clock of Unified Silla and float rods for measuring time, that is based on the Silla's calendaric system.

• Journal of the Korean Society of Costume
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• v.52 no.7
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• pp.13-25
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• 2002

The purpose of this study is to develope a creative expression technique in fashion illustration through analyzing applied techniques of the elements related to creative expressions in fashion illustrations. They were investigated in view of line, form, texture, color, space and the results were summarized as follows. In the creative expression using line in the fashion illustration. emotional effects of line created by specific character of mediums and duplicated lines have been applied to visualize movements of the objects. In shape, the transformed figure by destructing. covering or eliminating a part of the figure or the dress has been adapted. In texture. the invented texture reconstructed from actual texture has been applied, collage technique. computer graphic being used to give various images of texture. The creative expressions using color have been achieved by the shading. and spreading effects and the symbolic meaning of color for creating a spatiality in a picture plane and to give emotional effects and visual concentricity. In space, the color perspective together with detailed description. the combination of various points of view and liner perspective have been used to create depth and illusional space in pictorial plane.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.803-808
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• 2003

Several dielectric pipes buried in the lossy half space are reconstructed from the scattered fields measured along the interface between the air and the lossy ground. Iterative inversion method by using the hybrid optimization algorithm combining the genetic and the Levenberg-Marquardt algorithm enables us to find the positions, the sizes, and the medium parameters such as the permittivities and the conductivities of the buried pipes as well as those of the background lossy half space even when the dielectric pipes are close together. Illposedness of the inversion caused by the errors in the measured scattered fields are regularized by filtering the evanescent modes of the scattered fields out.

• Journal of the Korean Institute of Educational Facilities
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• v.17 no.2
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• pp.3-12
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• 2010

The purpose of this study was to provide the planning guideline for the multi-purposed classroom in the elementary school and middle school using questionnaire and user participation method. As the user participation method, the design workshop in the study contains participation techniques, community action planning, and participation game. The design workshop used the design kit as a communication tool. Four user groups, selected from teachers and child in the elementary school and middle school, to be reconstructed, participated in a design workshop with design kit, and each group produced their own plans. The result of this study is as follows; (1) Teachers wanted multi-purposed classroom to be used by two classes. (2) The size of the multi-purposed classroom was preferred 1.5 times(30 py.) of the regular classroom. (3) By considering the characteristics of students it was required the open space in elementary, but required it to be separated from the regular classroom in middle school. (4) Through the analysis, we could grasp the processes that the users' needs were practically applied to design. Our design workshop method should be hereafter modified and advanced, but showed the usefulness in many aspects.

• Journal of Astronomy and Space Sciences
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• v.38 no.3
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• pp.157-164
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• 2021

We describe a method for the in-orbit calibration of body-mounted magnetometers based on the CHAOS-7 geomagnetic field model. The code is designed to find the true calibration parameters autonomously by using only the onboard magnetometer data and the corresponding CHAOS outputs. As the model output and satellite data have different coordinate systems, they are first transformed to a Star Tracker Coordinate (STC). Then, non-linear optimization processes are run to minimize the differences between the CHAOS-7 model and satellite data in the STC. The process finally searches out a suite of calibration parameters that can maximize the model-data agreement. These parameters include the instrument gain, offset, axis orthogonality, and Euler rotation matrices between the magnetometer frame and the STC. To validate the performance of the Python code, we first produce pseudo satellite data by convoluting CHAOS-7 model outputs with a prescribed set of the 'true' calibration parameters. Then, we let the code autonomously undistort the pseudo satellite data through optimization processes, which ultimately track down the initially prescribed calibration parameters. The reconstructed parameters are in good agreement with the prescribed (true) ones, which demonstrates that the code can be used for actual instrument data calibration. This study is performed using Python 3.8.5, NumPy 1.19.2, SciPy 1.6, AstroPy 4.2, SpacePy 0.2.1, and ChaosmagPy 0.5 including the CHAOS-7.6 geomagnetic field model. This code will be utilized for processing NextSat-1 and Small scale magNetospheric and Ionospheric Plasma Experiment (SNIPE) data in the future.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.16-30
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• 1990

The microwave imaging technique which is mostly analyzed in the spectral domain has been exploited the image reconstruction of object using the 2-dimensional inverse Fourier transform so far. In this paper, a new method of microwave imaging corresponding to a coherent tomographic scheme in the space domain is presented for the conducting objects. Also, it is shown that image reconstruction for lines targets and conducting circular cylinder is per-formed by computer simulation using the filtered-backprojection which is the reconstruction algorithm widely used in X-ray CT. The proposed method analyzed in the space domain can reconstruct the image without any problems such as interpolation and image artifact which results from the reconstruction in the spectral domain for the symmetric conducting objects located in the origin. The image reconstructed by the filtered-backprojection in the space domain has given the superior quality compared with that produced by 2-dimensional IFFT using the interpolation scheme in the spectral domain. Finally, the image of line targets using the moment-method in the space domain which does not require the wide-band signal as the spectral domain has shown a possibility of super-resolution in the microwave imaging.