• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.964-967
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• 2001

Aspherical lens with the higher numerical aperture has been needed in the optical storage device to increase the recording density on the disk. However, high numerical aperture means the large slope angle at the clear aperture of the lens. Therefore, the measurement and manufacturing technique including the lens molding process for the slope angle should be developed. In this paper, the evaluation technique was described for the optical performance of the aspherical lens. Aspherical form error brings about the wavefront error and the side lobe of the beam intensity profile. A schematic diagram of the aspherical lens manufacturing was drawn to explain the aspherical form error compensation. Finally, form error of the aspherical lens was defined and plotted using the raw data of the Formtalysurf.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.245-246
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• 2018

This paper is a multipurpose functional synthetic resin formwork which can replace existing euro form. We tried to improve the disadvantages such as work noise, stenosis, recyclability, and workability of Euroform system. As a result of the test, Euroform showed an average of 106.7dB and synthetic resin formwork showed an average of 100.4dB. Therefore, it is considered that the synthetic resin formwork has a great effect of noise reduction compared to the euro form.

• Korean Institute of Interior Design Journal
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• no.39
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• pp.20-27
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• 2003

The purpose of this study is to provide a practical guide for selecting architectural artwork and analyze relationship between artwork and interior space & facade. The problems with many outdoor artwork did not make the characteristics of the specific environment and did not form a big flow in the urban contextualism. Choosing the artwork, architectural environment for artwork is very much part of the designers' task. When artwork is to be specifically acquired for a particular projects, designer and client must work together to make choices and plan placement. The data are collected through evaluation surveys of college students and graduate students majoring in interior architecture & design, and analyzed by using SPSS-WIN program to find the major characterized factors. It is concluded that architectural artwork should be constituted with nine major factors of interior space - theme/scale, situation/contemporay accord, finished materials harmony, line/two-three dimensional form, proportion/rhythm, sequence, natural/artificial form, abstract/reality expression, originality - and eight major factors of facade - situation, abstract/reality expression, finished materials harmony, theme/sequence, natural/artificial form, proportion/rhythm, static/dynamic expression, originality/. contemporay accord.

• Korean Journal of Construction Engineering and Management
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• v.17 no.5
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• pp.130-137
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• 2016

Owner's participation on a construction project can alter the success of a construction project. In general, success of a construction project is measured by project schedule and cost decrease without considering the role an owner has in a project. As a result, this research developed a framework for the project evaluation form and after extracting a total of 9 project critical success factors (CSF) and 27 sub-CSF. AHP method was utilized to evaluate the importance factor of each CSFs. Setting a goal for each CSFs at the beginning of a project and comparing the values at the completion of the project utilizing the project evaluation form will allow a systematic evaluation and management of a project. Solution Map was introduced and Solution Tool was suggested in order to utlize the evaluation results effectively. In the future studies, various project cases needs to be supplemented for further verification and a solution based on the evaluation result needs to be developed that can be applied to construction projects.

• Journal of the Korean Wood Science and Technology
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• v.44 no.6
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• pp.903-912
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• 2016

Morphological and anatomical evaluation of grafted P. merkusii have been undertaken to obtain the information about compatible and incompatible symptoms of 18 years old grafts based on morphological observation and microscopic analysis. Samples of compatible and incompatible grafts were obtained from previous research conducted by the Silviculture Departement Team in 1994. Result showed that compatible grafts have normal stem form and secondary growth (diameter growth), but some abnormality symptoms like undulated pattern of annual growth rings, phloem thickening and abnormality resin ducts in inner and middle parts of the union area occurred. Incompatible ones showed abnormality of the stem form, cortex-bark necrosis and swelling in the union area. Microscopic observation showed abnormality of all parts of the union, undulated pattern of annual growth rings, phloem thickening, abnormal resin ducts, low numbers and discontinuity of vascular elements in the union area.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.1
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• pp.1-13
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• 2002

We study a multi-component production/inventory system in which individual components are made to meet various demand types. We assume that the demands arrive according to a Poisson process, but there is a fixed probability that a demand requests a particular kit of different components. Each component is produced by a flow line with several stations. The production of each component is operated by the CONWIP control mechanism. To analyse this system, we propose an approximation method based on aggregation method. In application of the aggregation method, a product-form approximation technique as well as a matrix-geometric method is used. Comparisons with simulation show that the approximation method provides fairly good results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.378-381
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• 2003

Efficient development of method on a performance evaluation for machine tools has been regarded as the most important work for accuracy and quality enhancement to every user and manufacturer. A evaluation method of accuracy for machine tools has been studied recently according to the rapid increase of interest in precision machine tools. To this point of view, the circular interpolation test of machine tools is recognized as the most useful method to distinguish a dynamic accuracy of NC machine tools by ISO and ANSI/ASME, etc. In this paper, we have studied and developed the form measurement system with grid encoder to analyse the final accuracy of NC machine tools. we have analyzed the servo system error and geometric error of NC machine tools through measuring a dynamic error signal by this system. and then we verified the experimental result and enhanced the reliability by means of comparing the characteristics of the developed system with the kinematic ball-bar system.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.67-72
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• 2003

The present article evaluates a performance hall, which improves sound efficiency. In general, the sidewall of the music hall is plane circle. thus there happens a focus phenomenon. To overcome it. the music hall improves its sound efficiency by making its sidewall irregular. After measuring impulse response from the performance hall, evaluation indices on the temporal distribution of sound energy such as RT, EDT, D50, C80, RASTI and BR were obtained, and based on them, indoor acoustic characteristics and the generation of echoes were determined. According to the results, evaluation indices showed that the acoustic condition was satisfactory in general. This study is to provide fundamental data for acoustic design of music hall with round form by analyzing the room acoustic characteristics of music hall.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.459-466
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• 2002

The purpose of this study is to propose a new method for evaluating equivalent damping ratios of a structure with supplemental damping devices to assess their control effect quantitatively. A MDOF system is transformed to an equivalent SDOF system based on the assumption that the first mode dominates structural response. Approximate closed-form formulas for the evaluation of the first damping ratio are presented for various damping devices. Through numerical analysis of a ten-story building equipped with damping devices, the effectiveness of equivalent SDOF model and closed form formulas are verified.

• Asian Journal of Innovation and Policy
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• v.3 no.1
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• pp.94-116
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• 2014

The technological innovation is considered as an important factor and there is a positive externality in developing technology in the form of technology spillover. In this context, it is argued that government should play an active role in advancing technology development and several means have been introduced. This study attempts to analyze manufacturing firms' evaluation for the performance of government assistance programs to their R&D activities. Considering that the performance evaluation takes the form of a count outcome, we apply several kinds of count data models. Some interesting findings emerge from the analysis. For example, we found that a firm's sales amount, dummy for the firm's having an R&D department, dummy for the firm's being a venture one, and the number of the firm's innovative activities have positive relationships with the degree that the firm evaluates government assistance as being useful.