• The Journal of Korean Physical Therapy
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• v.31 no.1
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• pp.56-61
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• 2019

Purpose: The spasticity of stroke patients decreases the ankle range of motion and increases the gastrocnemius muscle tone. This study examined the effects of stretching exercise and far infrared irradiation on the ankle function in stroke patients with spasticity. Methods: This study was conducted on 20 stroke patients admitted to Jesaeng General Hospital, who were divided into a study group (stretching exercise with far infrared) and control group (stretching exercise only). The dorsiflexion range of motion was measured using a smartphone and the medial gastrocnemius muscle tone and stiffness were measured using a Myoton pro. Results: With the exception of the non-paretic gastrocnemius muscle tone in the control group, the medial gastrocnemius muscle tone and stiffness decreased significantly in both groups. In both groups, the dorsiflexion range of motion increased significantly. In addition, the experimental group had a significantly higher dorsiflexion range of motion than the control group. On the other hand, there was no significant difference between the two groups in terms of the medial gastrocnemius muscle tone and stiffness. Conclusion: For stroke patients with spasticity, stretching exercises increased the ankle's range of motion and decreased the gastrocnemius muscle tone. The addition of heat therapy further increased the ankle's range of motion. On the other hand, as the sample size was small, future studies should include more subjects.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.53-55
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• 2007

This paper describes an implementation of a wide-range dimming controller of a LED backlight for Avionics applications such as the control data unit(CDU) and multi-function display(MFD). A feedback controller using a light sensor is proposed to control the brightness in the low dimming range. The proposed controller provides an improved control performance in the wide dimming range of 1:3000 even under the temperature variations. The experimental results are provided to show the effectiveness of the proposed control system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.129-139
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• 2019

In order for a gun-launched guided projectile to glide to the maximum range, when to deploy the fin and start flight with guidance and control should be considered in range optimization process. This study suggests a solution to the optimal guidance problem for flight range maximization of the flight model of a guided projectile in vertical plane considering the aerodynamic properties. After converting the nonlinear Multi-Phase Optimal Control Problem to Two-Point Boundary Value Problem, the optimized guidance command and the best fin deployment timing are calculated by the proposed numerical method. The optimization results of the multiple flight rounds with various initial velocity and launch angle indicate that determining specific launch condition incorporated with the guidance scheme is of importance in terms of mechanical energy consumption.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.361-364
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• 1997

The re-enty guidance design involves trajectory optimization, generation of a reference drag acceleration profile with the satisfaction of trajectory constraints. This reference drag acceleration profile can be considered as the reference trajectory. This paper proposes the atmospheric re-entry system which is composed of longitudinal, later and range control. This paper shows the a performance of a re-entry guidance and control system using feedback linearization control and predictive control.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.183-186
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• 2002

The paper is proposed intantaneous torque control of IPMSM for drive of wide speed range. The control scheme is based on the mathematical model of the motor and is applicable to the constant torque and field weakening operations The scheme allows the motor to be driven with maximum torque per ampere (MTPA) characteristic below base speed and it maintains the maximum voltage limit of the motor wide field weakening and the motor current limit under all conditions of operation accurately. For each control mode. a condition that determines the optimal d-axis current $i_d$ for maximum torque operation is derived. The proposed control algorithm is applied to PMSM drive system for drive of wide speed range, the operating characteristics controlled by maximum torque control are examined in detail by simulation.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.182-185
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• 1998

This paper describes a field orientation control of an induction motor without any speed transducer and proposes a wide-range speed control strategy with the field orientation algorithm. The difference at impedances between the direct and quadrature axis at the injected signal is used for the sensorless field orientation control. But this algorithm has some limitations and should be supported by other method at high speed. In this paper, a sensorless speed control at an induction motor for wide speed range operation is proposed. The proposed algorithm is verified by experimental results.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.477-487
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• 2008

This paper proposes a new position sensorless drive for brushless DC (BLDC) motors. Typical sensorless control methods such as the scheme with the back-EMF detection method show high performance only at a high speed range because the magnitude of the back-EMF is dependent upon the rotor speed. This paper presents a new solution that estimates the rotor position by using an unknown input observer over a full speed range. In the proposed method, a trapezoidal back-EMF is modelled as an unknown input and the proposed unknown input observer estimating a line-to-line back-EMF in real time makes it possible to detect the rotor position. In particular, this observer has high performance at a low speed range in that the information of a rotor position is calculated independently of the rotor speed without an additional circuit or complicated operation process. Simulations and experiments have been carried out for the verification of the proposed control scheme.

• Physical Therapy Rehabilitation Science
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• v.10 no.3
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• pp.257-262
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• 2021

Objective: Patients with stroke generally diminished ankle range of motion, which decreases balance and walking ability. This study aimed to determine the effect of ankle self-mobilization with movement (s-MWM) on ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index in patients with chronic stroke. Design: Randomized controlled trial design Methods: Twenty-four post-stroke patients participated in this study. The participants were randomized into the control (n = 12) and self-MWM groups (n = 12). Both groups attended standard rehabilitation therapy for 30 minutes per session. In addition, self-MWM group was performed 3 times per week for 8 weeks. All participants have measured ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index in before and after the intervention. Results: After 8 weeks of training, self-MWM group showed greater improvement in ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index than in the control group (p<0.05). Further, self-MWM group had significantly improvement in all dependent variables compared to the pre-test (p<0.05). Conclusions: Our investigation demonstrates that self-MWM is beneficial for improving functional ability. Also, self-MWM was superior to control with respect to improving ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.649-659
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• 2016

This paper describes control algorithm and control structure of vehicle control unit for range-extended electric vehicle equipped with engine-generator system, and specially presents methods which determine optimal operating points and decreases a vibration or a shock for operating the engine-generating system. The vehicle control algorithm is consisted of several parts which are sequence control, calculation of wheel demand torque, determination of operating points, and management of operating points and so vehicle controller has be made possible to efficiently manage calibration parameters. The control algorithm is evaluated by driving test modes, launching performance and operating engine-generator system and so on. In conclusion, this paper present methods for extending a mileage, improving a launching performance and reducing vibration or shock when the engine-generating system is starting or is stopping.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.181-185
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• 2001

This paper presents a digitally speed sensorless control system for induction motor with direct torque control (DTC). The drive is based on Mode1 Reference Adaptive System (MRAS) using state observer as a reference model fat flux estimation. The system are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal, model reference adaptive control (MRAS) with rotor flux linkages for the speed turning aignal at low speed range, two hysteresis controllers. The Proposed system is verified through simulation.