• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.293-298
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• 1998

In surface grinding, the conditions of the grinding wheel give a significant effect on the ground workpieces comparing with other metal removal processes. In this paper, to assist the development, a non-contacting optical method is introduced to make in-process measurements of scattering intensities from laser beam during surface grinding processes. This show indications of changes in surface texture of wheel working surfaces. Also, in order to determine the dressing time monitoring method of grinding wheel in surface grinding, a three-dimensional computer simulation of the grinding operation has been attempted based on the contact mechanism and surface-shaping system between the grinding wheel and the workpiece. The optical dressing time is determined based on the amount of the grain wear and work surface roughness.

• World Technopolis Review
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• v.7 no.1
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• pp.44-58
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• 2018

The successful development of science parks is dependent on the relevance and delivery of a range of value propositions they offer to their stakeholders. Experience has shown that the benefits of these value propositions are 'place based' and 'time dependent', influenced by the prevailing technology, social and business environments in which they operate, and the relationship that is developed between entrepreneurs, corporates, academia and government in creating these projects, and their performance is dependent on economic, physical and networking assets they create and deploy. This paper looks at some of the history that has influenced the development of parks, lessons learnt from their planning, development and operation. It reviews these details in the context of delivering value propositions in the context of temporal, spatial, technology and entrepreneurial profile of the new idea of 'innovation districts', influencing 'city planning' and supporting 'smart specialisation strategies'.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.374-381
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• 2005

The ability to provide quality power has become a significant issue in power systems. The main causes of poor power quality are harmonic currents, poor power factor, supply-voltage variations, etc. A technique of achieving both active current distortion compensation, power factor correction and also mitigating the supply-voltage variation (sag or swell) at the load side is presented in this paper. The operation and rating issues of the proposed Single-phase Unified Power Quality Conditioner are also highlighted. To reduce the total cost while simultaneously increasing the performance, the system is fully digitally controlled using the fixed-point TMS320F240 digital signal processor. The performances of the UPQC, which is composed by shunt and series PWM controlled-converters, have been verified on a laboratory prototype.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.1033-1039
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• 1995

The magnetic system design of the KT-2 tokamak has been performed at KAERI. Design goal has been set to facilitate the so-called "advanced tokamak" studies, which is essential to secure the economy of the tokamak fusion reactors. Design features include a large-aspect-ratio machine configuration, long-pulse operation capability with heavy plasma shaping, hybrid magnetic field control and machine/in-vacuum structures for MHD stability.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.98-103
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• 2004

Recently, a New Great Harbour Bridge between Mokpo City and Koha Island is planned to be built across Mokpo Inner Harbour, and Namak New Town is under construction adjacent to Mokpo. Citizels' concorn of and participation in 「Campaign for Shaping Mokpo into Beautiful Seaport」 are necessary to match the view of Mokpo harbour with natural scenery beautifully and with marine environment harmoniously. Citizens'ㄹ levels of consciousness of coastal and marine environment were ascertained through questionnaire surveys of local citizenry attitudes and opinions, and citizenry action plans for the conservation of coastal and marine environments around Mokpo harbour are suggested on the basis of the results of questionnaire surveys. Citizens' voluntary participations in local policy for the control of marine wastes production and in a campaign for the collections of marine debris and wastes around beaches and coastal areas are required. The operation of municipal sewage treatment plants is to be performed effectively and efficiently, and to be monitored and evaluated periodically by the general public, the local federation for environmental movement or NGO. The development and performance of marine environmental education programs and an enlightenment campaign for environment preservation are to be incessantly done in cooperation with local residents. Only when local government of Mokpo collects the public opinions and continues to shape Mokpo into international beautiful seaport in the direction of a reflex of public opinion, coastal and marine environment around Mokpo harbour can be kept in good condition with citizens' positive participation in citizenry long-term practical action plans for environment conservation.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.387-390
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit Incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.237-244
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• 2005

Although the technique of vertical reduction mammaplasty has gained major popularity, it is difficult to perform and has the steep learning curve. The authors present a modification of the standard Lejour vertical mammaplasty that simplify the design and make it more reliable and easy to perform. We simplified the design by discarding the Mosque dome. From March 2000 to March 2004, we performed this technique for 40 patients with breast hypertrophy. The apex of the design was marked at the anterior projection of the inframammary fold. After resection of the breast tissue, the medial and lateral pillars were approximated. Then a new nipple-areola position was determined at 4.0-5.0 cm from a new inframammary fold. The range of resection amount of breast tissues was from 150 to 750 gram. Most of the patients were satisfied with the results. There was no permanent sensory loss and nipple areola skin necrosis. But there was 1 case of hematoma on the first day after the operation. This technique presents several advantages. It allows shaping and projection without compromising the future nipple position and makes it easier to remove an excessive skin around the areolae. And it may be comfortable to adjust the position of the nipple at the end of the procedure. We believe that this modification helps to improve the results of the vertical reduction mammaplasty.

• Journal of Korean Academy of Nursing Administration
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• v.15 no.3
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• pp.355-364
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• 2009

Purpose: The purpose of the research is to investigate the effect of self-image on work performance and controlling ability of self-leadership in relationship in between self-image and work performance. Methods: The data were collected from Mar 16th to April 15th 2009, a descriptive survey study was conducted with 140 nurses. Results: The hypothesis "Self image of nurse would affect on work performance" is supported ($R^2$=.335, p<.001). In the hypothesis of "Self-leadership would have controlling ability on self-image and work performance", as a result of regression analysis in independent variables of self-image(A) and self-leadership(B), adding relation of both variable($A{\times}B$) would increase in 36.6% (p<.05). Conclusion: Self-image of nurse was confirmed that it had positive effect on work performance and that it had moderating ability on relationship between self-image and work performance. The shaping and strategic operation are required to increase self-leadership and positive development on self-image of nursed.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1209-1210
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• 2006

This paper presents a single phase high power factor PWM boost rectifier featuring soft commutat -ion of the active switches at zero current. It incorporates the most desirable properties of conventional PWM and soft switching resonant techniques. The input current shaping is achieved with average current mode control and continuous inductor current mode. This new PWM converter provides zero current turn on and turn off of the active switches, and it is suitable for high power applications employing IGBT's. The principle of operation, the theoretical analysis, a design example, and experi -mental results from a laboratory prototype rated at 1.6[kW] with 400[Vdc] output voltage are presented. The measured efficiency and the power factor were 96.2[%] and 0.99[%], respectively, with an input current THD equal to 3.94[%], for an input voltage with THD equal to 3.8[%], at rated load.