• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.561-568
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• 2018

Passivity theory is significantly applied to analyze stability of nonlinear dynamic systems and construct its stable control systems. This paper presents a passivity based control design approach for exciters and governors which are employed to regulate the terminal voltage and the rotor velocity of synchronous generator systems in industry fields. We consider the IEEE type 1 exciter and the gas turbine (GT) governor models respectively in this paper. We first carry out a passivity analysis for exciter and governor control systems, which are numerically obtained from its mathematical models. And then its control parameters are selected to assure passivity conditions in a design procedure. Lastly, we investigate numerical simulations to demonstrate reliability of the proposed control approach against large-scale generators with parameter changes.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.258-263
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• 2011

In the bilateral tele-operation system, time delay may be a critical problem. Even if system modeling error or time delay occurs, when applied to wave transformation system, the system's stability can be achieved. Using the characteristic b which is an important parameter of wave transformation, the system can display robust performance for time delay. However, since assuming and that the time delay was fixed developing a theory, a stability cannot be guaranteed about the time-varying delay. Therefore, In the paper, Therefore, in this paper, we studied for the method that controls this by applying the fuzzy algorithm which surveyed the timevarying delay characteristics and can adjust the b according to it adaptively.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.4
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• pp.175-182
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• 2018

In recent years, micro-grid has been widely focused on the fields of renewal energy systems. This paper proposes a novel robust power converter control against arbitrary electric load changes for islanded micro-grid topology. First, we provide a state-space representation of our micro-grid model including power converter and electric load circuit. And then a state feedback control method is applied to construct a nominal control framework. Next, we propose a robust adaptive control law to enhance a control performance against unexpected load perturbation. In addition, we analytically investigate a passivity property for the micro-grid model and carry out computer simulation to demonstrate superiority and reliability of the proposed control methodology.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.10
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• pp.871-880
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• 2000

A twin-servo mechanism is used to increase the payload capacity and assembling speed of high precision motion control systems such as semiconductor chip mounters. In this paper, we focus on the modeling of the twin-servo system and propose its network representation. And also, we propose a robust synchronizing motion control algorithm to cancel out the skew motion of the twin-servo system caused by different dynamic characteristics of two driving systems and the vibration generated by high accelerating and decelerating motions. The proposed control algorithm consists of separate feedback motion control algorithms for each driving system and a skew motion compensation algorithm. A robust tracking controller based on internal-loop compensation is proposed as a separate motion controller and its disturbance attenuation property is shown. The skew motion compensation algorithm is also designed to maintain the synchronizing motion during high speed operation, and the stability of the whole closed loop system is proved based on passivity theory. Finally, experimental results are shown to illustrate control performance.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.46-55
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• 2006

This paper presents the control method for the hybrid actuator comprising a DC motor and an MR brake. Generally, a DC motor as an active actuator has a small power to weight ratio and goes unstable with higher force control gain due to its saturation limit. In order to cope with this instability and make the transparency higher, this paper proposes a hybrid actuator which consists of a DC motor and an MR brake as a passive actuator and its force control method based on network theory. A DC motor actively produces the output corresponding to the signs of the input currents. On the other hand, an MR brake passively resists against the external load independent of the sign changes of the input currents. This characteristics is widely known as 'passive' This paper suggests a force control method based on passivity concept in network theory for the hybrid actuator and verified its performance and stability through the experiments.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.302-305
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• 1999

Twin-servo mechanism is used to increase the payload capacity and speed of high precision motion control system. In this paper, we propose a robust synchronizing motion control algorithm to cancel out the skew motion of twin-servo system caused by different dynamic characteristics of two driving systems and the vibration generated by high accelerating and decelerating motions. This proposed control algorithm consists of separate feedback motion control algorithm of each driving system and skew motion compensation algorithm between two systems. Robust model reference tracking controller is proposed as a separate motion controller and its disturbance attenuation property is shown. For the synchronizing motion, skew motion compensation algorithm is designed, and the stability of whole Closed loop system is proved based on passivity theory.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.3
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• pp.329-335
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• 2003

Purpose: The purpose of this paper was to inquiry a philosophical foundation for the nursing ethics according to the Levinas' ethics which had emphasis on face to face interpersonal relationship and responsibility for the vulnerable other. Method: First of all, for the foundation of nursing ethics, a understanding of human vulnerability was a starting point; the nurse's bodily sensibility was regarded as a basis for the possibility of the ethical interpersonal relationship. Then, based on Levinas's ethics, it was explained how the moral responsibility for the calling of the suffering other could occur in nursing situation. Result: Nursing implied the altruistic ethical dimension on the subject of the responsibility for the vulnerable other. A nurse as ethical subject in her sensitive passivity is affected by the suffering other and exposed to the other. A nurse herself/himself has to response to the ethical demand of suffering other and to take responsibility for it. After all, based on the Levinas's ethics, the ethical interpersonal relationship could be characterized as the face to face relation, and responsibility for the suffering other. Conclusion: In view of that, his ethical approach could be a proper theory for the explanation of the face to face relationship and altruistic feather of the nursing ethics based human bodily sensibility.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.180-187
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• 2021

This thesis explores the place and role of a performer's action from a perspective of a director and playwright David Mamet's concept for performer training. This thesis takes inspiration from the idea of Mamet's simple and practical investigation specifically in text-based approach with a performer's bodily function on stage. For Mamet, the writings and practices of many different body-centered training are not rooted in the principle and nature of acting/performance. Reconsidering complicated approaches particularly psychological-oriented theory, practice, and assumption draw on several practitioners takes us beyond the field of visible and/or outer appearance of a performer which in turn leads the performer's body to be as abstract therefore not to being in the moment on stage. Arming the points, we argue that whatever disciplines and/or methods necessarily need to meet the principles and demands of acting/performance/theatre to connect to the materials, an action/objective given by a specific playwright which the performer must inhabit through his/her body. Out of the context, any 'method' serves no purpose. That is, the mechanics of an action is an extension of addressing what a performer's specific needs which shifts his/her body to respond appropriately to the theatrical demands. Taking this argument further, we claim that the purpose of performer training should not be understood as learning and improving techniques or skills for his/her self-perfection. The research finding shows that this resembles to the phenomenon that the visible very often precedes the invisible where the performer's body lose a clarity with no more chance to happen and/or change the event(s). Rather, it is a process of learning what/how to learn which in turn brings us back to the central question of why we do training for what purpose in this contemporary era. Exploring and answering these questions is not only a way to employ the key materials applicable to the theatrical demands but also to achieve the identify as a professional performer/doer on stage.

• Korean Journal of Social Welfare
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• v.66 no.1
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• pp.139-162
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• 2014

This paper critically examines the existing discourses about 'relationship', a key element of social work practice and questingly examines Lao-tzu's work of Tao Te Ching, the book of way and virtue, as an alternative theoretical framework for social work relationship. Compared to current discourses of relationship beleaguered by either modernism or postmodernism, both of which are in the deadlock of binary perspective, the insights and vision in Tao Te Ching are successfully able to overcome the limits of them and provide new and profound way of thinking about human, society and their relationship. Especially core cannons crystallized by natural humanistic concepts for cosmos coupled with innate critical power against artificial manipulations of world can extend the horizon of understanding concerning the relationship between client and social workers and therefore provide a new and attractive roles in professional relationship. Moreover, opposed to usual images of Lao-tzu's ideas such as nihilism and passivity, alternative relationship of social work can play an important role of caring the disordered reality where Dao disappered and criticise the selfish desires of individuals and comport the broken-hearted minds in modern society. In addition, results of this paper implies that more extended study articulating ideas of Tao Te Ching with the social work practice would have lots of potentials to promote later researches in quest of 'Korean' social work practice.