• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2246-2248
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• 2001

This paper presents a new vector control scheme for induction motor. An exact knowledge of the rotor flux position is essential for a high-performance vector control. The position of the rotor flux is measured in the direct schemes and estimated in the indirect schemes. Since the estimation of the flux position requires a priori knowledge of the induction motor parameters, the indirect schemes are machine parameter dependent. The rotor and stator resistance among the parameters change with temperature. Variations in the parameters of induction machine cause deterioration of both the steady state and dynamic operation of the induction motor drive. Several methods have presented to minimize the consequences of parameter sensitivity in indirect scheme. In this paper, new estimation scheme of rotor flux position is presented to eliminate sensitivity due to variation in the resistance. The simulation is executed to verify the proposed vector control performance and to compare its performance with that of indirect and direct vector control.

• 한국식생활문화학회지
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• 제24권5호
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• pp.496-505
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• 2009

This study was conducted to provide basic data and insight into behaviors that result in increased continuous sales and competitiveness. This was done by examining the effect of personal involvement on customer satisfaction and trust, the effect of customer satisfaction on switching cost and loyalty, the effect of trust on switching cost and loyalty and by analyzing the indirect effect of trust and loyalty to personal involvement on switching cost and loyalty of the patrons of casual dining restaurants. In order to achieve the goals of the study, a hypothesis and structural equation were proposed based on preceding research and the proposed model was analyzed using LISREL 8.30 to prove the hypothesis and better understand the interactions between the cause and effect. The results were as follows: Six proposed hypothesis were chosen and the indirect effect was verified. In other words, customers' personal involvement was shown to have an effect on trust and devotion and satisfaction influenced switching cost and loyalty. Trust had an effect on switching cost and loyalty and by analyzing the indirect effect the customers' personal involvement was shown to affect the switching cost and loyalty through satisfaction and trust. The result of this analysis provides clues to better understand the eating-out behavior of customers and proves that personal involvement, satisfaction, trust, switching cost and loyalty are directly and indirectly related.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.454-457
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• 1997

As in most industrial processes, the dynamic characteristics of an electric power system are subject to changes. Amongst those effects which cause the system to be uncertain, faults on transmission lines are considered. For the stabilization of the power system, we present an indirect adaptive control method, which is capable of tracking a sudden change in the effective reactance of a transmission line. As the plant dynamics are nonlinear, an input-output feedback linearization method equipped with nonlinear damping terms is combined with an identification algorithm which estimates the effect of a fault. The stability of the resulting adaptive nonlinear system is investigated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.680-687
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• 2000

In this paper we present a new vector control scheme for induction motor. An exact knowledge of the rotor flux position is essential for a high-performance vector control. The position of the rotor flux is measured in the direct scheme or estimated in the indirect schemes. Since the estimation of the flux position requires a priori knowledge of the induction motor parameters, the indirect schemes are machine parameter dependent. The rotor resistance and stator resistance among the parameters change with temperature. Variations in the parameters of induction machine cause deterioration of both the steady state and dynamic operation of the induction motor drive. Several methods have been presented to minimize the consequences of parameter sensitivity in indirect scheme. In this paper new estimation scheme of rotor flux position is presented to eliminate sensitivity due to resistance change with temperature. Simulation results are used to verify the performance of the proposed vector control scheme.

• Journal of Power Electronics
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• 제19권5호
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• pp.1142-1152
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• 2019

This paper presents a control method for reducing the current distortion in an indirect matrix converter (IMC) operating in boost mode under unbalanced input conditions. IMCs operating in boost mode are useful in distributed generation (DG) systems. They are connected with renewable energy systems (RESs) and the grid to transmit the power generated by the RES. However, under unbalanced voltage conditions of the RES, which is connected with the input stage of the IMC operating in boost mode, the input-output currents are distorted. In particular, the output current distortions cause a ripple of the power, which is transferred to the grid. This aggravates the reliability and stability of the DG system. Therefore, in this paper, a control method using positive/negative sequence voltages and currents is proposed for reducing the current distortion of both side in IMCs operating in boost mode. Simulation and experimental results have been presented to validate effectiveness of the proposed control method.

• Membrane and Water Treatment
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• 제10권4호
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• pp.299-305
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• 2019

Managed aquifer recharge (MAR) systems are gaining interest as an alternative to conventional water resources. However, when the water recovered in MAR systems, dissolved iron and manganese species may easily oxidize and they cause well screen clogging or require abandonment of extraction wells. In this study, both oxic and anoxic conditions were analyzed to verify the feasibility of the membrane filtration performance under various solution chemistries. The fouling mechanisms of the metal ions under anoxic conditions were also investigated by employing synthetic wastewater. The fouled membranes were then further analyzed to verify the major causes of inorganic fouling through SEM and XPS. The newly suggested anoxic process refining existing membrane process is expected to provide more precious information about nanofiltration (NF) membrane fouling, especially for demonstrating the potential advantages to chemical-free drinking water production for indirect potable reuse.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2371-2373
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• 2000

This paper presents a new vector control scheme for induction motor. An exact knowledge of the rotor flux position is essential for a high-performance vector control. The position of the rotor flux is measured in the direct scheme and estimated in the indirect schemes. Since the estimation of the flux position requires a priori knowledge of the induction motor parameters, the indirect schemes are machine parameter dependent. The rotor and stator resistance among the parameters change with temperature. Variations in the parameters of induction machine cause deterioration of both the steady state and dynamic operation of the induction motor drive. Several methods have presented to minimize the consequences of parameter sensitivity in indirect scheme. In this paper, new estimation scheme of rotor flux position is presented to eliminate sensitivity due to variation in the resistance. The simulation is executed to verify the proposed vector control performance and to compare its performance with that of indirect vector control.

• 경영정보학연구
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• 제18권2호
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• pp.107-125
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• 2016

모바일 앱 시장이 발달하면서 사용자들이 앱을 사용한 만큼 기부에 참여할 수 있는 새로운 모바일 기부 앱이 등장하였다. 새로운 형태의 모바일 기부 앱은 모바일 앱의 기능과 기부의 시너지 효과를 통해 기부 시장을 활성화할 수 있을 뿐만 아니라 차별화된 모바일 앱 서비스를 제공함으로써 모바일 앱 시장을 확장한다는 점에서 중요한 의의를 지닌다. 그럼에도 불구하고 어떠한 종류의 모바일 기부 앱 서비스가 사용자의 사용 의도를 증대시킬지에 대한 연구는 부족한 실정이다. 본 연구는 공익연계 마케팅 이론을 바탕으로 어떠한 형태의 모바일 기부 앱이 사용 의도에 더 큰 영향을 미치는지를 밝히고자 한다. 이를 위하여 첫째, 직접적 혹은 간접적 모바일 기부 앱이 지각된 효과성과 공익 관여도를 매개로 하여 모바일 기부 앱 사용 의도에 어떠한 영향을 미치는지에 대한 실험을 모바일 앱 사용자들을 대상으로 실시하였다. 분산분석 결과, 간접적 모바일 기부 앱이 직접적 모바일 기부 앱보다 지각된 효과성과 공익 관여도에 더 높은 영향을 미치며 PLS 경로 분석을 통하여 지각된 효과성과 공익 관여도가 높을수록 모바일 기부 앱 사용 의도를 높아진다는 사실을 확인하였다. 추가연구에서는 간접적 모바일 기부 앱의 실용적, 쾌락적 속성이 지각된 효과성과 공익 관여도에 어떠한 영향을 미치는지에 대한 실험을 진행하였다. 그 결과, 실용적 속성이 더 많은 영향을 준다는 사실을 일원분산분석을 통하여 입증하였다. 본 연구의 결과는 모바일 기부 앱 활성화를 위해 실증적인 디자인 가이드라인을 제공해줄 수 있을 것이다.

• 한국안전학회지
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• 제29권6호
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• pp.1-8
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• 2014

Safety certification and inspection of dangerous machines and equipments used in industries are to save lives of workers and properties involved. Cause analysis of industrial accidents is essential to prove the effectiveness of such certification and inspection. This study focuses on suggesting systematic method for cause analysis of industrial accidents associated with dangerous machines and devices. Incorporating transition from the current user-oriented indirect regulations to more manufacturer and user balanced direct regulations, suggested method coupled with safety certification, safety inspection, safety management and safety education will guarantee more effective prevention of industrial accidents.

• 한국안전학회지
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• 제33권1호
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• pp.16-21
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• 2018

Cause analysis of accidents associated with industrial machines and devices is essential to improve the effectiveness and the efficiency of industrial safety system in Korea. This study focuses on cause analysis of accidents associated with industrial machines and devices. In particular, analysis of abstracts of accidents which are written in descriptive format and, therefore, inherently unstructured and exhibits characteristics of big data is suggested and tested. Automatic analysis of such big data performed in this study reveals the consistent results with the manual analysis results in previous studies. Analysis results also suggest that incorporating transition from the current user-oriented indirect regulations to more manufacturer and user balanced direct regulations will guarantee more effective prevention of industrial accidents at the early stage of generation of danger.