• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.7
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• pp.384-390
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• 1999

This paper describes a new ac-to-dc power converter using a multilevel converter. A conventional multilevel ac-to-dc converter has large output dc filter capacitors. When a short circuit happens in a load, the stored energy in the capacitors should be discharged through the load with a high short circuit current. The high current may cause considerable damage to the capacitors and the load. The output dc capacitors of the proposed converter do not discharge even under load short circuit condition. In the case of a load short circuit, the capacitors become a floating state immediately and remain in the state. Then the stored capacitor energy is supplied to the load again as soon as the short circuit has been cleared. Therefore, the rising time of the load voltage can be significantly reduced. This feature satisfies the requirement of a power supply for a load with frequent short circuits. The proposed converter has the characteristics of a simplified structure, a reduced cost, weight, and volume compared with conventional power supplies with frequent output short circuits. Experimental results are presented to verify the usefulness of the proposed converter.

• Culinary science and hospitality research
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• v.6 no.2
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• pp.227-246
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• 2000

A few years ago, hotel service was not usual to the people very much but it's normally usual only for the higher-grade people. However now a days, it's expected that hotel service is universal one with changing of life style. It's rising to use hotel with being on the increasing of the international alternating so that the banquet service can be expected as the much more important service point of hotel. At the same time there are much more chances to participate in the personal parties and meetings. That means the demand is increasing than before. So every hotels are trying to promote the quality of the service, make renovation and suggest the specially distinguished service in comparison with the other hotels so as to get the banquet customers. Actually the sales amount from the banquet in the hotel can be said the biggest one in these days. That's why we cannot help thinking it the very important point at the hotel service. So we would 1ike to suggest the best way of managing hotel banquet service more efficiency and would like to find out how we can serve the higher quality service to the banquet customers in order them to make feel more satisfactory.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.2
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• pp.122-128
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• 2000

With the rising innovative antigens(such as intruders and viruses) through Internet, new secure schemes are expected to perceptively detect and put them down. However, the current hosts over Internet could not properly analyze Internet antigens due to limitations of their system and network resources. In this paper, we introduce an Antibody Layer that mediates proper security services based on the biological mechanism to mpidly disclose and remove innovative antigens. The proposed Antibody Layer also provides three classes to make agreed-on security parameters set up easily with respect to real-time security QoS for one host as well as host alliances.

• Analytical Science and Technology
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• v.7 no.1
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• pp.17-23
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• 1994

Through sol-gel process, inorganic/organic composite as a dye host was made. It was observed that this composite has about 90% of trnasmittance by UV/VIS spectrophotometer. The transmittance is the most important requirement to decide whether the composite could apply or not as the dye host. The transmittance was increased with decreasing HCl as a catalyst, aging time, and amount of PDMS. Also, fluorescent and transmittant charateristics of Rhodamine 6G Perchlorate that was doped into ORMOSIL were measured. The fluorescent intensity was increased and the trnasmittance was decreased with rising gelling temperature.

• Journal of Korean Society for Quality Management
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• v.42 no.3
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• pp.477-496
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• 2014

Purpose: This paper has examined the impact of open innovation business model in technology commercialization with the data from 30 companies of manufacturing firms in South Korea. Methods: The findings provide support for distinguishing five hypotheses relating to development time, IP management, sales, firm size and R&D intensity. To test the hypotheses, data were collected using via e-mail and fax. Small and medium-sized (less than 300 employees) and large industrial firms were chosen for this study. Results: The result shows that openness in its business model is positively associated with successful technology commercialization. Conclusion: The major findings and the implications are: First, as the business model gets more open, development period of technology will be more favorable which gets benefit from rising costs of innovation. Second, as the business model gets more open, large portion of sales are created from new products. Thus, the problem of shorter product life in the market which affects large portion of market revenue can be solved through an open business model. Third, in general, R&D intensity, firm size and the level of IP management affect determination of business model types. The findings also suggest that companies need to increasingly address their external technology exploitation process instead of focusing on their internal innovation processes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1018-1023
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• 2005

A new MR cylinder with built-in valves using MR fluid (MR valve) is suggested and fabricated for fluid control systems. The MR fluid is a newly developed functional fluid whose obvious viscosity is controlled by the applied magnetic field intensity. The MR cylinder is composed of cylinder with small clearance and piston with electromagnet. The differential pressure is controlled by the applied magnetic field intensity. It has the characteristics of simple, compact and reliable structure. The size of MR cylinder and piston has ${\varphi}30mm{\times}300mm\;and\;{\varphi}28.5mm{\times}120mm$ in face size, respectively and 0.8mm in gap length. Through experiments, it was found that the differential pressure is controlled by the applied magnetic field intensity under little influence of the flow rate, which corresponds to a pressure control valve. The differential pressure of 0.47MPa and contact force of 320N were obtained with the input current of 1.5A. The rising time of force was 1.1s in step response of a manipulator using the MR cylinder. The effectiveness of the MR cylinder was also demonstrated through the force control.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.59-66
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• 2011

This work treat the modeling and simulation of non-linear dynamic behavior of a web winding process during traction. We designate by a winding process any system applying the cycles of unwinding, transport, treatment, and winding to various flat products. This system knows several constraints, such as the thermal effects caused by the frictions, and the mechanical effects provoked by metal elongation, that generates dysfunctions due to the influence of the process conditions. Several controllers are considered, including Proportional-integral (PI) and Backstepping control. This paper presents the study of Backstepping controls strategy of the winding system. Our winding system is simulated in MATLAB SIMULINK environment, the results obtained illustrate the efficiency of the proposed control with no overshoot, and the rising time is improved with good disturbances rejections comparing with the classical control law.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.80-86
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• 2011

This paper presents an integrated variable amplitude high voltage pulse generation circuit with low power and small size for driving industrial piezoelectric printer heads. To solve the problems of large size and power overhead of conventional pulse generators that usually assembled with multiple high-cost discrete ICs on a PCB board, we have designed a new integrated circuit (IC) chip. Since all the functions are integrated on to a single-chip it can achieve low cost and control the high-voltage output pulse with variable amplitudes as well. It can also digitally control the rising and falling times of an output high voltage pulse by using programmable RC time control of the output buffer. The proposed circuit has been designed and simulatedd in a 180[nm] Bipolar-CMOS-DMOS (BCD) technology using HSPICE and Cadence Virtuoso Tools. The proposed single-chip pulse generation circuit is suitable for use in industrial printer heads requiring a variable high voltage driving capability.

• Journal of The Korean Digital Architecture Interior Association
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• v.10 no.2
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• pp.13-20
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• 2010

Uncertainty in housing price fluctuation has great impact on the overall economy due to importance of housing market as both place of residence and investment target. Therefore, estimating housing market condition is a highly important task in terms of setting national policy. Primary indicator of the housing market is a ratio between rent and transaction price of housing. The research explores dynamic relationships between Rent-Transaction price ratio, housing transaction price and jeonse rental price, using Vector Autoregressive Model, in order to demonstrate significance of shifting rent-transaction price that is subject to changes in housing transaction and housing rental market. The research applied housing transaction price index and housing rental price index as an indicator to measure transaction and rental price of housing. The price index and data for price ratio was derived from statistical data of the Kookmin Bank. The time-series data contains monthly data ranging between January 1999 and November 2009; the data was log transformed to convert to level variable. The analysis result suggests that the rising ratio between rent-transaction price of housing should be interpreted as a precursor for rise of housing transaction price, rather than judging as a mere indicator of a current trend.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.3
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• pp.88-95
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• 2015

The accelerated thermal aging of CSPE(Chloro Sulfonate Polyethylene) was carried out for 40.41, 121.22, 202.04 days, 16.82, 50.45, 84.09 days and 7.32, 21.96, 36.59 days at 100, 110, and $120^{\circ}C$, respectively, which are equivalent to 20, 60, 100 years of aging at $50^{\circ}C$. The permittivities and the apparent densities of the accelerated thermally aged CSPE samples are increased with accelerated thermal aging year but EAB(Elongation at Break) is decreased with that. The dielectric strength and the electric breakdown of the non-accelerated and accelerated thermally aged CSPE samples do not depend on accelerated thermal aging year and applied voltage rising time. density and EAB measures.