• Korean Journal of Optics and Photonics
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• v.29 no.4
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• pp.166-172
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• 2018

In this paper, we propose a new method to predict a mirror's surface deformation due to the stress of moisture release by a coating in the environment of outer space. We measured the surface deformation of circular samples 50 mm in diameter and 1.03 mm thick, using an interferometer. The results were analyzed using Zernike fringe polynomials. The coating stress caused by moisture release was calculated to be 152.7 MPa. This value was applied to an analytic model of a 1.25 mm thickness sample mirror, confirming that the change of surface deformation could be predicted within the standard deviation of the measurement result ($78.9{\pm}5.9nm$). Using this methodology, we predicted the surface deformation of 600 mm hyperbolic mirror for the Compact Advanced Satellite, which will be launched in 2019. The result is only $2.005{\mu}m$ of focal shift, leading to 2.3% degradation of modulation transfer function (MTF) at the Nyquist frequency, which satisfies the requirement.

• Korean Institute of Interior Design Journal
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• no.40
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• pp.3-9
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• 2003

Today the social concern about Interior Design gradually requires wide comprehension. Also according to demanders' requirement. Colleges cope with speed. Interior Design made by experts for the function and purpose in the conception of decoration. Therefore, Colleges are responsible to educate for more capable professional designers. But management is the first concern for Interior Design Company students are going to work at. Interior Design has not the important state yet in Korea, it is hard to manage the company with only design works on the table. As architectural design side must get some admission, design is apart from construction. but they are worked together in Interior Design. Also, as the architectural design with process detail drawings, interior design is required the detail design for construction. But it is the facts that the college is interested in and concentrated on rather education for design and space plan than intensive education for construction because of the restricted environment of practice room. I propose component and practical use of nude construction department to understand detailed design.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.266-269
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• 2002

As a simulation or replacement of analog money in cyber space, the e-cash was introduced by using cryptographic primitives. Since a perfect anonymity system causes some illegal activities, such as money laundering, blackmailing, and illegal purchase, a revocable electronic system was paid a great attention to control the anonymity. In general, Trust Third Party(TTP) is introduced to detect any dubious user and coin, namely user tracing and coin tracing. In this paper we propose a new revocable anonymity e-cash system, and verify the security requirement as well. In our scheme a user first withdraws the e-coin from bank by using blind signature, and then TTP verifies the bank's signature and records the tracing information.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.04a
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• pp.33-37
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• 1989

According to the Rayleigh-Ritz approximation method, a solution can be represented as a finite series consisting of space-dependent functions, which satisfy all the geometric boundary conditions of the problem and appropriate smoothness requirement in the interior of the domain. In this paper, an efficient formulation for solving structural dynamics systems in frequency domain is presented. A general procedure called Ritz modes (or vectors) generation algorithm is used to generate the admissible functions, i.e. Ritz modes, Then, the use of direct superposition of the Ritz modes is utilized to reduce the size of the problem in spatial dimension via geometric coordinates projection. For the reduced system, the frequency domain approach is applied. Finally, a numerical example is presented to illustrate the effectiveness of the proposed method.

• Journal of Agricultural Extension & Community Development
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• v.2 no.1
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• pp.41-54
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• 1995

The purposes of the study were to find out the basic needs of rural people and to get some implications for the integrated rural regional development. The data were gathered from 376 local government officers and change agents in 8 Provinces. Major results of study were as follows ; (1) Average income of rural households meet $90{\sim}100$ present of average income of urban households. (2) Most of respondents replied that average labor inputs should not exceed $7{\sim}8$ hours per a day. (3) Basic requirement of school career for the rural life was high school graduate. (4) Education expenditure should be less then 6 percent of total consumption expenditure. (5) Rural people should be able to access to basic public facilities such as school, hospital and drag store within thirty minitues. (6) Desirable housing space for rural life was $66{\sim}72.5m^2$. (7) Rural people should enjoy $3{\sim}4$ times of cultural activities and $3{\sim}4$ times of tours in a year.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.77-83
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• 1999

Due to the high cost of constructing anechoic chamber, the multi-usage of a chamber in various applications is very effective in terms of cost as well as space. In this paper, we describe an anechoic chamber currently used at SK Telecom in Korea. This is designed for the measurements of both far/near field antenna and EMC/EMI in the identical chamber. This anechoic chamber and measurement system support antenna test in the frequency range of 150 MHz to 40 GHz and meet the requirement of ANSI C63.4 and CISPR 16.1 for EMC/EMI.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.1
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• pp.129-135
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• 2000

In 1997, Yongsan-gu Office of Seoul held a design competition for 'Hyochang Park as a holy Grounds'. Although various shrines and monuments were located in it, Hyochang Park had lost its sense of pace as a 'holy grounds' mostly by its neighborhood-park-like atmosphere at its entrance area. Specific requirement for this competition was designing a 'symbolic object' to make this park more 'holy grounds' looking. However, it was very regretable that Yongsan-gu Office did emphasized on the 'object' rather than on the space or place in this design competition. Three points were emphasized in the winning scheme proposed by the author: where the object be located in the park, how the object be connected with the rest of the park, and how the object harmonized with some of traditional looking architectures and shrines. The purpose of this paper is to articulate the concept of the winning entry in detail and to describe how the concept actualized in reality.

• Journal of the Korean Mathematical Society
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• v.37 no.6
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• pp.1043-1057
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• 2000

This paper is devoted to the investigation of mixed Fourier-Bessel transformation (※Equations, See Full-text) We apply the method of [6] which provides the estimate for weighted L(sub)$\infty$-norm of the spherical mean of │f│$^2$ via its weighted L$_1$-norm (generally it is wrong without the requirement of the non-negativity of f). We prove that in the case of Fourier-Bessel transformatin the mentioned method provides (in dependence on the relation between the dimension of the space of non-special variables n and the length of multiindex ν) similar estimates for weighted spherical means of │f│$^2$, the allowed powers of weights are also defined by multiindex ν. Further those estimates are applied to partial differential equations with singular Bessel operators with respect to y$_1$, …, y(sub)m and we obtain the corresponding estimates for solutions of the mentioned equations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.187-190
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• 2005

There have been many studies to improve the performance of a database system focused on modifying data structure, data partitioning, and materializing strategy. The main contribution of this study is to propose a new alternative towards improving database performance by designing single table schema or processing queries virtually in main memory space. Material Requirement Planning(MRP) part explosion process has shown almost 2 times shorter under DB schema we suggested, and even more than 10 times shorter when separating and filtering policy of DB archiving process are assumed. Several experimental results are shown to illustrate the excellence of our solution.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.489-492
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• 2005

As a former level of MSC(Multi Spectral Camera) telescope of the KOMPSA T2satellite, the several performance tests of EOS(Electro Optical Subsystem) were performed in the EOS level. By these tests, not only the design requirement of payload can be verified but also the test result can be the important criterion to estimate the performance of payload in the launch and space orbit environment. The EOS Geometric Mapping test is to verify the accuracy of the alignment & assembly on the Subsystem of the MSC by measurement like these; LOS(Line of Sight), LOD(Line of Detector), Band to Band Registration, Optical Distortion and Reference Cube. This paper describes the test results and the analysis for the EOS Geometric Mapping.