• Proceedings of the KIEE Conference
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• 2001.07d
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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.

• Journal of the Korean Society of Food Culture
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• v.24 no.5
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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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• 1997.10a
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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.

• Proceedings of the KSR Conference
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• 2000.11a
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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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• v.19 no.5
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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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• v.10 no.4
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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.

• Proceedings of the KIEE Conference
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• 2000.07d
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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.

• Information Systems Review
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• v.18 no.2
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• pp.107-125
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• 2016

With the rapid growth of the mobile application market, mobile donation applications have emerged as a new type of application that enables users to donate without actual payments. To date, limited research has been conducted to provide guidelines on how to design new types of mobile donation applications. Using cause-related marketing theory as theoretical framework, this study aims to identify the features of mobile donation applications that increase the intention of users to use such applications. To achieve this goal, we conducted two experiments. The results of an ANOVA test in the first experiment showed that indirect mobile donation applications (i.e., applications without actual payment) have a stronger positive effect on perceived effectiveness and cause involvement than direct mobile donation applications (i.e., applications with actual payment). In addition, perceived effectiveness and cause involvement yield positive effects on the intention to use mobile donation applications. The results of the second experiment showed that indirect mobile donation applications with utilitarian functions have a greater positive effect on perceived effectiveness and cause involvement than mobile donation applications with hedonic functions. These results contribute to mobile application and donation research as well as provide guidelines for practitioners on the design of mobile donation applications.

• Journal of the Korean Society of Safety
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• v.29 no.6
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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.

• Journal of the Korean Society of Safety
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• v.33 no.1
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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.