• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.148-153
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• 1998

In order to control thermal deformation of machine origin of machine tools due to internal and external heat sources, the real-time compensation system has been developed. First, GMDH models were constructed to estimate thermal deformation of machine origin for a vertical machining center through the measurement of deformation data and temperature data of specific points on the machine tool. Thermocouples and gap sensors are used respectively for measurement. These models are nonlinear equations with high-order polynomials and implemented in a multilayered perceptron type network structure. Secondly, work origin shift method were developed by implementing digital I/O interface board between CNC controller and IBM-PC. The work origin shift method is to shift the work origin by the compensation amounts which is calculated by pre-established GMDH model. From the experimental result, thermal deformation of machine origin was reduced to below $\pm$5${\mu}{\textrm}{m}$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.185-189
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• 2009

It is very important to control the vibration transmitted from external utilities and the transient response due to the internal sources for the precision equipment, which is very sensitive to the vibration environment. The anti-vibration tables that use air springs have been widely used due to their excellent isolation performance, but the systems with high flexibility have the critical problem of large transient response by the impulsive force of the moving mass in operation of the equipment. In this paper, the hybrid vibration control system is proposed, which is combined the air springs with the semi-active MR dampers in order to satisfy the performances of isolation and vibration reduction simutaneously.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.213-218
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• 1997

Thermal deformation of machine origin of machine tools due to internal and external heat sources has been the most important problem to fabricate products with higher accuracy and performance. In order to solve this problem, GMDH models were constructed to estimate thermal deformation of machine origin for a vertical machining ceneter through measurement of temperature data of specific points on the machine tool. These models are nonlinear equations with high-order polynomials and implemented in a multilayered perceptron type network structure. Input variables and orders are automatically selected by correlation and optimization procedure. Sensors with small influence are deleted automatically in this algorithm. It was shown that the points of temperature measurement can be reduced without sacrificing the estimation accuracy of $\pm$5${\mu}{\textrm}{m}$. From the experimental result, it was confirmed that GMDH methodology was superior to least square models to estimate the thermal behavior of machine tools.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.5-5
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• 2010

The depth of the object pointed by the laser beam is computed depending on the pixel position on the CCD There involved several number of internal and external parameters such as inter-pixel distance, focal length, position and orientation of the system components in the depth measurement error. In this paper, it is shown through the error sensitivity analysis of the parameters that the most important parameters in the sense of error sources are the angle of the laser beam and the inter pixel distance. Also, the calibration technique to minimize their effect for the depth computation is proposed.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.12 no.2
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• pp.148-160
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• 1999

In order to strengthen objectivity and availability of oriental herb medicine, the standard formula for herbs has been attempted to set up by documentary testing original herbs which were recorded in authorized document. The object herb medicines are CARYOPHYLLI FLOS. After this study, additional experimental verification is required as a matter of fact. As comparison materials, this thesis will be utilized. Specially the internal and external morphological standard in this study is expected to supply the search for several physiochemical reaction, biological reaction, determination of indicator material and identification of gene with basic sources in the future.

• Journal of the Korean Home Economics Association
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• v.38 no.7
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• pp.79-92
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• 2000

The purpose of this study is to verify the soundness of homelife and the stress of home management perceived by housewives living in Seoul as well as to investigate how the soundness of home life affects the stress of home management. In total, 914 housewives were studied to serve as a data sources. The major result are as follows : 1. Communication variables huts the strongest effect on the soundness of home life. 2. Wife's self-actualization influences the soundness of home life and home management stress. 3. Wife's internal-external control has an positive effect on the soundness of home life and home management stress. 4. The soundness of home management variables-family unification, time, psychological health, human ability, physical health should be developed as human capital.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.352-355
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• 2001

In this paper, we proposed measurement error reduction technique for the semiconductor device DC characteristic measurement system. Implemented system is composed of 4 SMUs, 2 VSUs, and 2 VMUs. Various efforts in hardware and software have been made to reduce the measurement errors due to the leakage current in measurement circuits. Internal and external sources of errors in measurement system especially in pA range measurement have been identified and removed. Experimental results show that the implemented system can be measure the DC characteristic of semiconductor devices in pA level.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.593-600
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• 2007

This paper presents the preliminary observations of an ongoing study that is looking into organisational changes that are externally imposed using the institutional theory. The study population are the government-linked companies involved in housing development (GLCHD) in Malaysia. For the purpose of this paper, only two are highlighted. From secondary sources, elements of changes that have exerted on these two GLCHD over the last six years and the internal changes that have taken place during the same time period were identified. The tentative conclusion is that external environment contributed to organisational change in the two GLCHD.

• International Commerce and Information Review
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• v.12 no.2
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• pp.325-355
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• 2010

Knowledge-based exporting companies in Korea have reached a stage to develop new technological innovation and to pioneer new markets. But, developing new technologies and launching new products require an enormous sum of money for Research and Development(R&D) and there is still uncertainty in technological development and markets. Therefore, through open technological innovation, they are encouraged to actively use external technological sources and ideas. They also need to enhance the efficiency of the relatively little R&D investment. In this paper, firstly, it conducts a precedent study on the concept and influence factors of knowledge-based exporting companies and open technological innovation. Secondly, it sets a study model and estimates a regression coefficient to analyze the influence factors of open technological innovation of knowledge-based exporting companies which are using external resources on the process of innovation. Through case study and empirical analysis, we are going to find the implication of open technological innovation and prepare the way of the innovation for the knowledge-based exporting companies. According to the empirical analysis, variables such as firm size, processing degree, product life, patent registration, maintaining internal security didn't have positive effects on open innovation performance. On the other hand, research capability and market preoccupancy had positive effects. Therefore, to succeed in open innovation, knowledge-based exporting companies not only need to secure research capability through open innovation, but also need to preoccupy the market through commercialization of developed product.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.469-477
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• 2006

When denitrification was connected with a single stream process by using biofilter and sulfur-limestone, it was found that such connection enabled highly efficient nitrification without special unit operation of microorganisms or injection of external carbon sources which is being shown in general biological treatment processes. It was observed that in the trickling filter bed, decomposition of organic substances and highly efficient nitrification by both the forced pressure feed trickling and the air fan were simultaneously done. In the denitrification tank where sulfur-limestone was mixed at a certain ratio, limestone was used by autotrophic microorganisms as a source of supply for alkalinity, and nitrate $NO_{3}^{-}$-N was denitrified into nitrogen gas. And in the sulfur-limestone autotrophic denitrification, $NO_{3}^{-}-N\;or\;NO_{2}^{-}-N$ was denitrified as a sulfur compound in reduction state was oxidized into a final output of $SO_{4}^{-2}$. The mean concentration of the discharge water was 8.6 mg/l for T-N and 0.8 mg/l for T-P, respectively, and their mean treatment efficiency was 79.2% and 80.8%, respectively. Implementing highly efficient denitrification without injection of an external organic carbon source or internal return, it is concluded that the proposed process is suitable for a sewerage in a small village with the merits of low power consumption and easy maintenance.