• Journal of Power Electronics
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• v.3 no.3
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• pp.167-174
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• 2003

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. Although high resolution optical encoders or resolvers are used to provide a precise position information, these sensors are expensive. Moreover, in the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. And the control algorithm to generate switching signals using a Simple digital logic is presented. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.527-530
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• 2007

Film compensation to suppress a light leakage in the dark state of fringe-field switching (FFS) at off normal direction was performed by optimizing retardation value of discotic (negative A) and TAC films including in-plane switching (IPS). The normal FFS mode shows wide viewing angle characteristics that region of CR 10:1 is over $70^{\circ}$ of polar angle in all directions. The optimized FFS cell exhibits much better performances than other methods do in terms of CR and color uniformity.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.402-409
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• 1999

Variable structure control law is well known to be a robust control algorithm and evolution strategy is used as an effective search algorithm in optimization problems. In this paper, we propose a variable structure controller with time-varying switching surface. We calculate the maximum value of seitching surface gradient that is of the 3rd order polynomial form. Evolution strategy is used to optimize the parameters of the switching surface gradient. Finally, the proposed method is applied to position tracking control for BLDC motor. Experimental results show that the proposed method is more useful than the conventional variable structure controller.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.511-513
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• 2004

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.815-817
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• 1993

In this paper, it is considered spike voltage that is generated by ignoring the recovery time of switching device, turn on and turn off time. In the same principle, this spike voltage will be applicable to diode recovery time. The spike voltage causes to break down insulation of input transformer. So, we will show how to remove spike voltage by optimizing value of R and C and using switching diode which have fast recovery time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.131-137
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• 2003

We have performed computer simulation to obtain electro-optic chracteristics of reflective liquid crystal display (LCD) using wide viewing angle LC mode, fringe field switching(FFS). Unlike other reflective LCD modes, in the FFS mode, the LC director in plance so an application to reflective display consisted of polarizer, LC layer and reflector is possible. when an incident light is 550mm, the optimal cell retardation value is 0.1365${\mu}$m and the efficiency of reflectivity is high over 90% with very little wavelength dispersion. Further, we have studied a new reflective display with polarizer, optical compensation film with half plate, LC plus reflector. The display with optimized cell parameters shows high contrast ratio (CR) over 130 with high light efficiency over 90% at normal direction and the CR greater than 5 exists over 60$^{\circ}$ of polar angle in all directions.

• Journal of Global Scholars of Marketing Science
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• v.16 no.3
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• pp.61-86
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• 2006

The main purpose of this study is to conceptualize and investigate the relationships between the antecedents and outcomes of customer satisfaction and the linking variables of brand preference and repurchase intention in service industries. To achieve this objective, the study tries to validate the structural equation model and causal relationships among the model's elements involving antecedents to customer satisfaction(perceived quality, value, equity), consequences(brand preference, repurchase intention), and moderating variable/switching cost, customer loyalty). Empirical findings are as follows: First, the effect of two antecedents/perceived quality and value) on customer. satisfaction was accepted but perceived equity was rejected. Second, I found out that there were direct or indirect relationships between the mediating variables/switching cost, customer loyalty, brand preference) and repurchase intention. This means that the proper management concerned with indirect path is probably more important for the success of services industries. Third, the direct effects of customer satisfaction and switching cost on repurchase intention were not significant against the existing studies excepting brand preference. This implies that repurchase intention was mainly intensified by the indirect path, 'customer loyalty${\rightarrow}$brand preference${\rightarrow}$repurchase intention' and 'switching cost${\rightarrow}$brand preference${\rightarrow}$repurchase intention.' The service marketers make efforts not only to strengthen the direct casual linkage but also to consolidate the indirect connections leading to create repurchase intention. Finally, the proper management of these structural relationships will help clarify the role of service marketer resulting in increasing sustainable competitive advantage in service industries.

• Journal of Korea Technology Innovation Society
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• v.18 no.1
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• pp.176-203
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• 2015

While the importance of adopting cloud computing service has been emerged, comparatively little research has been conducted on examining factors of an individual user's intention to switch toward cloud computing service. Hereafter, this study presents and empirically tests users' intention to switch to cloud computing. Our model posits that the characteristics of cloud computing such as effectiveness, economics, accessability, switching cost, security concern, and satisfaction toward existing IT service to cloud service affect perceived value, which in turn, influences intention to switch. An experimental study using student subjects provided empirical validation for our proposed model. Survey data from 204 respondents was used to test the model using partial least square analysis. As the result of the analysis, five hypotheses out of seven hypotheses were supported. According to our results, among the characteristics of cloud computing, effectiveness, economics, switching cost, and security concern were found to have significant impact on users' intention to switch that mediated by perceived value. Based on our research findings, we hope that this research will stimulate researchers' interest in the emerging area of cloud computing adoption.

• The KIPS Transactions:PartA
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• v.8A no.3
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• pp.279-286
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• 2001

This paper proposes a low power resource allocation and scheduling algorithm that minimized power consumption such as DSP circuit in high-level synthesis process. In this paper, we have used list-scheduling method for low power design in scheduling step. Also, it increase possibility to reuse input through resource sharing when assign resource. After scheduling, the resources allocation uses the power function in consideration of the result of calculating average hamming distances and switching activity between two input. First, it obtain switching activity about input value after calculate average hamming distances between two operator and find power value make use of bit pattern of the input value. Resource allocation process assign operator to minimize average hamming distance and power dissipation on all occasions which is allocated at each control step according to increase control step. As comparing the existed method, the execution time becomes fast according to number of operator and be most numberous control step. And in case of power that consume, there is decrease effect from 6% to 8% to be small.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2668-2670
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• 1999

In the past, the PWM converter had a large switching loss by hard switching and difficult to high frequency operation. The resonance converter to decrease the switching loss and EMI is required the frequency control and needed to reduce the voltage or current stress at each parts. So, this paper propose the 3-phase boost converter and the method to compensated input power factor by control the amplitude - an instantaneous value of the DC inductor current -and control the switching frequency that a modulation error by the ripple of the DC inductor current. The proposed 3-phase PWM boost converter of single phase control type can takes higher capacity and compensate the power factor by using Feed back controller at each phase for the existing 3-phase bridge rectifier type. Moreover the 3-phase full bridge type using the rectifier at each 3-phase circuit will be small size reactor and compensate input power factor by minimize harmonic components of each phase.