• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5738-5743
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• 2014

This paper evaluated an electric wheelchair control algorithm by slope recognition on uneven terrain. Nowadays, the population using wheelchair has been increasing rapidly due to increases in the elderly population. On the other hand, most wheelchairs are directly controlled by the user without any device capable of securing the safety of the user. This causes difficulties in wheelchair control from the influence of gravity on the slope. This paper proposes a vehicle control algorithm that can move a wheelchair similar to moving on a plane. At that time, sensors are not used to recognize the degree of the slope. All processes were verified by simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1256-1264
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• 2009

When unapproved users access to healthcare system and use medical information for other malicious purposes, it could severely threaten important information related to patients' life, because in ubiquitous environment healthcare service makes patient's various examination results, medical records or most information of a patient into data. Therefore, to solve these problems, we design RBAC(Role Based Access Control) for U-healthcare that can access control with location, time and context-awareness information like status information of user and protect patient's privacy. With implementation of the proposed model, we verify effectiveness of the access control model for healthcare in ubiquitous environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5434-5441
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• 2013

Using longitudinal data of 575 sample from 122 firms in large business conglomerates from 2001 to 2008, this study examines the impact of controlling shareholders' control-ownership disparity on executive compensation. The empirical study finds that controlling shareholders' control-ownership disparity is negatively related to the level of executive compensation and moderate negatively the relation between firm performance and executive compensation. This finding suggests that controlling shareholders' control rights in excess of ownership rights lead to decreased executive compensation in order to relieve the concerns of stakeholder about the potential agency costs of controlling shareholder, and have, on the other hand, entrenchment effects on the decision of executive compensation by decreasing its sensitivity on firm performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5558-5563
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• 2011

Using longitudinal data of 108 firms in large business conglomerates from 2001 to 2009, this study examines the impact of controlling shareholders' control-ownership disparity on R&D investment. The study finds that control-ownership disparity is negatively related to R&D intensity. This empirical result suggests that controlling shareholders' control rights in excess of ownership rights incent controlling shareholders' expropriation for their private interests, leading to decreased R&D investment which enhances firm value in the long term.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.33-38
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• 2013

The general purposed control system for driving a motion of many different typed robot end-effector, which consists of a controller based on ARM Cotex M3-11017 MCU and an application software for generating a motion of end-effector, was developed. Experimental results show that a positioning error is nearly negligible and a repeatability error is 0.04%. Accordingly the developed control system can be applied practically to actuate a robot end-effector for inspection and maintenance of steam generator heat pipe in nuclear power plant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4610-4615
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• 2013

In this study, optimal operation strategies to save the electric energy and power price in the building central cooling system is researched by experiments. The optimal strategies of demand response control and outdoor temperature reset control algorithms are applied by consideration the electric energy and power price according to the energy consumption characteristics. The suggested optimal control method shows better responses in the power price and energy consumption in comparison with the conventional one and saves energy consumption by 9.5% and electronic price by 15.7%, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1066-1073
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• 2014

This paper presents a new design method of optimal control of system which are changed the system parameters. The method used for this purpose are the Lagrange interpolation method and Pole's Moving range method. We selects a system within the scope of the changing the system parameters. Using pole's moving range we calculated the state weighting matrix of optimal control. The optimal controller is designed by Lagrange interpolation method of the state weighting matrix. We are compared with a traditional optimal controller and proposed method by simulation. The simulation showed that the proposed method is better control performance than traditional method of optimal controller.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.5
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• pp.413-420
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• 2004

In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining method of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. In order to solve the problem which the unbalanced system control is used to leakage transformer not equaled reactance by each phase in rectifier system. The proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.8
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• pp.824-830
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• 2013

We propose a tracking control system for butterfly valves. A sliding mode controller with a fuzzy-neural network algorithm was applied to the design of the tracking control system. The control scheme used the real-time update law for the unmodeled system dynamics using a fuzzy-neural network algorithm. The performance of the proposed control system was assessed through a range of experiments.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.1
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• pp.22-29
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• 2007

Two fuzzy controllers defined by 2 input variables cooperate to control a cartpole system in terms of balancing as well as centering. The cooperation is due to the BOXES scheme that selects one of the fuzzy controllers for each time step according to the content of box that is established through the critic of the control action by the fuzzy controllers. It is found that the control scheme is good at controlling the cartpole system so that the system is stabilized fast while the BOXES develops its ability to select proper fuzzy controller through experience.