• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.47-52
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• 2001

This paper presents a high-performance control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor position/speed estimator, torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter, and F240/C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. To prove the suggested control algorithm, we have a simulation and testing at actual experimental system. The developed digitally high-performance position sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw RSM.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.272-275
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• 1997

When a manipulator makes contact with an object having position uncertainty, performance measures vary considerably with the control law. To achieve the optimal solution for this problem, an unique objective function that weights time and impact force is suggested and is solved with the help of variational calculus. The resulting optimal velocity profile is then modified to define a sliding mode for the impact and force control. The sliding mode control technique is used to achieve the desired performance. Sets of experiments are performed, which show superior performance compared to any existing controller.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2551-2554
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• 2003

In this paper, we describe the nonlinear character for a friction control. The nonlinear character of friction control is inherent in mechanical system, which has gained more and more interest. The modeling and compensation of nonlinear friction are difficult tasks for precise motion control. This paper is performance evaluation of nonlinearities and mechanical compliance exists together with friction control system.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.187-195
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• 2011

Glass Envelope is vulnerable to insulation performance and controling solar radiation. Insulation performance is consistently improving these days due to recent building energy saving policy in South Korea. However, solar control at glass envelope is still limited to meeting requirements of ideal high performance. Generally, Inside Blind plays an important role of solar control instead of glass which have a characteristics of transmitted solar. Unfortunately, most of them are controled by occupants and which method is not resonable in building energy. Therefore, achieving the high efficient performance building, automated control blind system considering reduction of building loads have to be adopted. Furthermore, considering occupants visual comport about removing discomfort glare is also essential.

• Journal of Korean Public Health Nursing
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• v.35 no.3
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• pp.343-355
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• 2021

Purpose: This study aimed to identify the effects of nursing students' ethical awareness, ethical decision-making and attitude toward performance on intention about performance of infection control guidelines in pandemic infectious diseases. Methods: The survey was performed on 163 nursing students in three universities. Data were collected using a structured questionnaires and analyzed with t-test, analysis of variance (ANOVA), Pearson's correlation and multiple regression analysis. Results: Perceived health status, ethical awareness and attitude toward performance of infection control guidelines about major commitment were significant predictive variables. These variables accounted for 48.1% of the variance in major commitment. Conclusion: The findings indicate the necessity of developing educational programs to enhance nursing students's ethical awareness, and increase performance of control guidelines to prepare for the pandemic infectious diseases.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.12
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• pp.535-541
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• 2002

This paper proposes an adaptive fuzzy controller based fuzzy logic control for high performance of permanent magnet synchronous motor(PMSM) drive. In the proposed system, fuzzy control is sued to implement the direct controller as well as the adaptation mechanism. The adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of adaptive fuzzy controller is evaluated by simulation for various operating conditions. The validity of the proposed controller is confirmed by performance results for PMSM drive system.

• Journal of Korean Society for Quality Management
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• v.30 no.3
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• pp.150-167
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• 2002

Normative theory suggests that control systems should be designed to complement management's objectives and strategies. However, few empirical studies have focused on how control systems have been modified to complement new manufacturing techniques, such as zero-defect strategy. The major purpose of this study is to examine the effects of the attributes of quality strategy and control system on performance. The previous studies have subdivided quality strategy into the ECL(economic conformance level) and ZD(zero-defect) strategy. To accomplish the purpose, this study empirically analysed the data based on the questionnaires from manufacturing department personnel of 67 Korean companies. The major results are as follows. The companies that had implemented the ZD strategy and its control system outperformed the companies that had implemented ECL strategy. Also, the ZD strategy differs from ECL strategy in control system, the criteria of performance evaluation and feedback frequence variable. There is no difference in quality performance monitoring and communication variable. From this results, although many companies have strived for continuous improvement of quality, it was restricted in improvement activities that dont's required much investment cost, quality performance monitoring and communication.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1179-1181
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• 2001

For high performance induction motor drives such as mill drives, elevator, spindle drive, NC and so on, smart speed controls is usually required, that requires a precise current control. This paper is proposes design of fuzzy controller which makes use of the output voltage of the space vector PWM inverter. Also, proposes the performance fuzzy controller for high performance vector control of induction motor drive system. The performance of a fuzzy controller is compared with that of an PI controller in an internal loop. The validity of the proposed technique is confirmed by simulation results for induction motor drive system.

• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.61-69
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• 2002

In the actual control systems, there exist many kinds of restrictions or nonlinearities. However, due to the nonlinearities in actuators and sensors, the designed controller may not be applicable in some practical situations. One such nonlinearity is amplitude saturation in actuators. Although sometimes it may be ignored, in other cases failure to consider actuator saturation may severely degrade closed-loop system performance and even lead to instability. On the other hand, limiting the controller gain to avoid saturation sacrifices control effort and may lead to loss of performance. Consequently, in some cases, the actuator saturation must be explicitly taken into account to ensure desired performance. However, in this paper, an anti-windup control system design method is introduced to suppress the windup due to the amplitude saturation of the actuator. The proposed control system has very simple design process and guarantees the good control performance. The validity of the proposed control system will be shown by comparing with the results of a reported paper.

• Journal of Korea Multimedia Society
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• v.9 no.6
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• pp.693-699
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• 2006

Object-oriented databases (OODBs) have been adopted for managing non-standard applications such as computer-aided design (CAD), office document management and many multimedia applications. One of the major characteristics of OODBs is class hierarchy where a subclass is allowed to inherit the definitions defined on its superclasses. In this paper, I present the evaluation metrics for class hierarchy quality in OODBs. These metrics are developed to determine if a concurrency control scheme can achieve good performance or not on a given class hierarchy. I first discuss the existing concurrency control schemes for OODBs. Then I provide evaluation metrics based on structural information and access frequency information in class hierarchies. In order to discuss significance of the proposed performance metrics, an analytical model is developed. Analysis results show that the performance metrics are important factor in concurrency control performance. I consider both single inheritance and multiple inheritance. The proposed metrics can be used to provide guidelines on how to design class hierarchy of an OODB for maximizing the performance of concurrency control technique.