• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1460-1462
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• 1994

BiCMOS is the newly developed technology that integrates both CMOS and bipolar structures on the same integrated circuit. Improved performance can be obtained from combining the advantages of high density and low power in CMOS with the speed and current capibility advantages by bipolar. However, the major drawbacks to BiCMOS are high cost, long fabrication time and difficulty of merging CMOS with bipolar without degrading of device Performance because CMOS and bipolar share same process step. In this paper, N-Well CMOS oriented BiCMOS process and optimization of device performance are studied when N-Well links CMOS with bipolar process step by 2D process and 3D Device simulation. From the simulation, Constriction of linking process step has been understood and provided to give the method of choosing BiCMOS for various analog design request.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.117-124
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• 2016

Solar photovoltaic pumping system is one of most important of renewable energy applications especially in rural areas. Besides, the control strategy for standalone solar pumping system based on induction motor and without DC/DC converter has been widely studied and discussed in the literature. This topology is of great concern due its economic issues, especially when a standard frequency converter (SFCs) with scalar control is used instead of a dedicated PV inverter. This paper proposes an external control module to generate SFCs frequency reference in order to ensure both maximum power point tracking (MPPT). We present method of modeling and control of photovoltaic pumping system based centrifugal pump controlled by new improved incremental conductance in order to optimize the price and operation of pumping system this MPPT algorithm have many advantages like can be eliminate proportional integral controller It is a low cost solution since it requires no additional power equipment. The induction motor driven pump that is powered by a solar array is controlled by the indirect field oriented control (IFOC). The effectiveness of the proposed approach is illustrated by simulations carried out under Matlab Software. The experimental results are compared with simulation results.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1589-1596
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• 2015

A novel control method of a three-phase PWM inverter with LC filter is proposed. The transfer function of LC filter is the same as that of 2nd order low pass filter(2nd LPF) which has a zero damping ratio. A simple method of implementing 2nd LPF with damping ratio is to add resistor to inductor or capacitor of LC filter. In an industrial application, it is not practical to adopt damping resistor because it results in losses being proportional to square of current flowing through resistor. Instead of using damping resistors, the proposed active damping control(ADC) utilizes all pass filter(APF) and considers inherent processing delay of digital controller. The overall transfer function of the proposed method is the same as a 2nd LPF and its damping ratio is also controllable via control variables. Detailed design and implementation of controller is also presented. Experiments are conducted with a 7.5kVA induction motor drive system controlled by PWM converter and inverter. Test waveforms are also presented to verify the proposed LC filter control algorithm.

• Journal of Mechanical Science and Technology
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• v.14 no.11
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• pp.1216-1224
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• 2000

The collapse pressure of tubes is determined experimentally by Tschoepe and Maison for various materials with different geometries. The results are compared with those obtained by ASME Codes UG-31 and UG-28. A collage pressure is the pressure required for the incipient yielding stress of the tubes with and without ovality. This collapse pressure is compared with the experimental results by Tschoepe and Maison. The present investigation is towards finding the collapse pressure required to bring the entire wall of tubes into a state of plastic flow for the pipes, with ovality and without ovality. This collapse pressure is compared with the collapse pressure obtained through experiments in the present investigation. The experimental results are compared with the pressure obtained by FEM(finite element methods). The FEM results are then compared with results obtained through an approximate plastic analysis of the strain hardening material, SA312-TP304 stainless steel. The structural integrity evaluation is performed for the heat exchanger used in an actual nuclear power plant by using various methods described in this paper. The results obtained by the various analyses and the FEM are discussed. consequently, the paper is oriented towards an actual design purpose of d heat exchanger in an industrial environment, rather than for the purpose of an academic research project investigation.

• Journal of Preventive Medicine and Public Health
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• v.43 no.6
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• pp.505-512
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• 2010

Objectives: Because of the changing life style of Koreans, we have witnessed an increase of patients with back pain. The development of medical knowledge and technology has resulted in more numerous and better treatment methods. However, the outcomes of diverse treatments have been examined by using a few medicine-oriented measures like pain. This study aims at identifying the factors that influence the outcomes of back pain treatments by using two outcome measures (e.g., quality of life and pain). Methods: We used the questionnaire survey method for data collection. The questionnaires contained 5 categories (treatment methods, clinical conditions, exercise, quality of life and, socio-demographic characteristics). We interviewed 188 back pain patients. We used the regression analysis method to predict the quality of life or pain. Results: Surgery showed a statistically significant effect on the quality of life as well as pain. The illness period, age and exercise were turned out to be significant factors for both of the dependent variables. The social class and surgery methods showed a statistically significant effect solely on the quality of life. Conclusions: In choosing the surgical methods, doctors need to provide detailed explanations on the quality of life outcomes for each of the surgical methods to the patients.

• Asia pacific journal of information systems
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• v.20 no.4
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• pp.25-51
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• 2010

This study compares and contrasts the intellectual development of the MIS field in Korea from 2005 to 2009 to that of international trends by using a keyword co-occurrence network analysis of the two flagship journals: APJIS and MIS Quarterly. From 316 research articles in these two journals, 132 unique and most frequently co-occurred keywords were put into analysis. The results of structural equivalence show a mild correlation between APJIS and MIS Quarterly. The e-commerce, trust, and technology adoption are the high frequency keywords in both journals. In Korea e-learning, purchasing, and recommendation systems turn out to be important keywords while outsourcing, research method, quantitative method, design research, information theory, and empirical research are in average international journals. This connotes that the Korean scholarship tends to focus more on practically oriented topics, but the clustering and relational mapping of research topics in each journal show a mild level of overlap with distinctive orientations due to intrinsic disparities depending on the concerned journals' geographical scopes, namely domestic or global.

• Journal of the Korea Furniture Society
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• v.20 no.3
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• pp.213-221
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• 2009

This study aimed at developing furniture for children by Ilgumte which is an expert manufacturer of educational equipments for school and kindergarten and the aim of this investigation is to develop the child-oriented furniture in consideration of Ilgumte's characteristic as a company composed of the disabled people, and furthermore to create a new sales market by developing own technology to improve competitive power. The current status of the child furniture in domestic and international market was researched and design concept on basis of this analysis was set, and through the designing process the new items of furniture having characteristics as follows were developed. First, the simple production way for the disabled to be able to work was selected and plywood used mainly by Ilgumte was presented as main material. Second, moving course, space and storage function were maximum considered, so that children feel convenient at using the furniture in their space, in case of playing as well as leaning. Third, natural wooden texture was mostly reflected for the emotional aspects of children and pink color played a role as partial accents. Finally, difficult production skill and expensive material were excluded for cost down.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.05a
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• pp.131-136
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• 2007

According to the OECD Report, Korea passed the first threshold to an "aging society" in which the elderly aged over 65 make up at least 7 percent of the population in 2000, and in 2018, are due to pass the second to an "aged society" in which they make up at least 14 percent-just 18 years later. It took France (starting in 1864) 115 years to complete this transition. Even Japan, legendary for the rapidity of its aging, required 24 years. It means Korea has to prepare for the aging of its population within a very short time without mistakes. Meanwhile, in a 2005 survey of the elderly, 85.5% of them preferred aging in place to moving to elderly care facilities. That means housing planning for the elderly which provides them with independent living needs to be considered seriously. The digital technology integrated home may be one of the alternatives to support this idea. In order to find a way to user oriented digital homes for the elderly, this study identified the their needs on the physical features of the ideal home and the digital services necessary through digital life scenarios.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1851-1863
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• 2017

Interior permanent magnet synchronous motor (IPMSM) is most commonly used in the automotive industry as a traction motor for electric vehicle (EV). In electric vehicle, the torque output rapidly changes according to the operation of the accelerator and the braking of the driver. The transient torques are thus generated very frequently in accordance with the variable speed control of the driver. Therefore, in this paper, a method for improving the torque response in the transient states of IPMSM is proposed. In order to complement the disadvantages of the conventional PI current controller in the field oriented control (FOC), the finite-state model predictive current control and 2D-LUT is applied to improve the torque response at the torque transient period. Simulation and experiment results are given to verify the reliability of the proposed method.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.4
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• pp.61-84
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• 2003

This study empirically examined the impact of national culture on the amount of information provided by management accounting information systems (MAIS). Two very different cultures, the Korean and Australian cultures, were considered in our study The results showed that the much more flexibility performance information is provided in Korean firms, while the amount of quality performance information and traditional cost control information (TCCI) produced in Australian firms is much more than in Korean firms. However, it was found that in the amount of financial performance information and advanced cost control information (ACCI), there exist no significant differences between Korean firms and Australian firms. We also investigated the effect of the three-way interactions among national culture, level of advanced manufacturing technology (AMT), and information on production performance. The results of this study revealed a significant impact of three-way interactions on the improvement of production performance. In conclusion, we suggest that under high levels of AMT, Korean firms need a large amount of information-based MAIS, while Australian firms require the ACCI and nonfinancial performance information-oriented MAIS.