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Hyo Jeong Kim1,2,Jun Hyuek Yang,Hyun Soo Kim,Yeo Jin Kim,Wonhee Jang,Young Rok Seo,W. Jang,Y. R. Seo 대한독성 유전단백체 학회 2017 Molecular & cellular toxicology Vol.13 No.1
I ntensive usage of electronic appliances containing lithium batteries causes an accumulation of e-trash. Environmental exposure to lithium batteries contaminates ecosystems. In air and water, the batteries form lithium hydroxide (LiOH) on their surfaces. LiOH enters the aquatic environment and contaminates the aquatic ecosystem by being absorbed into biological organisms. In this study, in order to identify meaningful potential biomarkers that appear in response to lithium, we measured significantly up- and down-regulated genes after LiOH exposure by conducting a microarray. In addition, we explored the functions of differentially expressed daphnia genes, and we conducted a comparative analysis in other species, Daphnia spp. to humans, then analyzed the signaling pathways using the human gene set derived from daphnia sequences that are differentially expressed in response to LiOH using the NCBI-BLAST tool and Pathway studio. As a result, we identified signaling pathways and suggested several potential biomarkers that are up- or down-regulated in response to lithium. This study may contribute to the development of a biomonitoring system which can detect the ecotoxicity of lithium. Furthermore, lithium toxicity in humans can be predicted, so the study may also provide potential biomarkers of lithium exposure in humans.
The compilation of Inventory of National Biological Resources with 111 Alert Alien Species in Korea
Soen-Yi Kim,Jin-Whoa Yum,Neung-Ho Ahn,Hye-Woo Byun,Mi-Jeong Jeon,Sung-Hee Jung,Hyun-Ki Choi,Youn-Bong Ku,Eun-Joo Woo,Min-Ha Kim,Wonhee Kim,Byung-Jik Kim,Hwa-Jung Kim,Min-Seock Do,Chang-Mu Kim 한국응용곤충학회 2023 한국응용곤충학회 학술대회논문집 Vol.2023 No.04
Wonhee Kim,Chung Choo Chung 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
Global output tracking and rejection of multi biased sinusoidal disturbances with unknown frequencies for nonlinear systems is considered. Disturbance observers (DOBs) in the form of a high pass filter are proposed to estimate multiple biased sinusoidal disturbances with unknown frequencies. The nonlinear control method is designed to compensate the estimation errors of the disturbances and guarantee the global output tracking. The matching conditions is no significant in the proposed method. The proposed method imposes no restriction on the number of disturbances, and no restriction such as biased sinusoidal signals. Therefore, the complete rejection of multi sinusoidal disturbance with stabilization can be achieved by the proposed method.
Kim, Wonhee,Lee, Youngwoo,Shin, Donghoon,Chung, Chung Choo The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.5
This paper presents a compensative microstepping based position control with passive nonlinear adaptive observer for permanent magnet stepper motor. Due to the resistance uncertainties, a position error exists in the steady-state, and a ripple of position error appears during operation. The compensative microstepping is proposed to remedy this problem. The nonlinear controller guarantees the desired currents. The passive nonlinear adaptive observer is designed to estimate the phase resistances and the velocity. The closed-loop stability is proven using input to state stability. Simulation results show that the position error in the steady-state is removed by the proposed method if the persistent excitation conditions are satisfied. Furthermore, the position ripple is reduced, and the Lissajou curve of the phase currents is a circle.
Passivity based Nonlinear controller for Position Tracking Control of Electro-Hydraulic Servo System
Wonhee Kim(김원희),Jongpyo Han(한종표),Indeok Choi(최인덕),Daehee Won(원대희),Chung Choo Chung(정정주) 제어로봇시스템학회 2008 제어로봇시스템학회 국내학술대회 논문집 Vol.2008 No.10
This paper presents a passivity controller for position control of electro-hydraulic servo system. Passivity based controller was designed to consider 5th order state space model of the hydraulic actuator which has a second order servo valve dynamics. Simulation results showed that position tracking performance of proposed controller is effective by bandwidth, step response, and path tracking test.
Wonhee Kim,Jongpyo Han,Induk Choi,Chung Choo Chung 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In this paper, iterative learning control (ILC) with field oriented control is proposed to reject periodic velocity ripple which are casually detent torque and other various sources in permanent magnet stepper motor(PMSM). Singleinput single-output (SISO) system structure with field-oriented control (FOC) is proposed to be applied to ILC. To make the error convergence fast, current error based ILC using plant inversion method is designed. The condition that error converges to zero is derived. Simulation results show that the velocity ripple is cut in by using ILC.
Lyapunov-based Microstepping Control of Sawyer Motors with PID Control
Wonhee Kim,Donghoon Shin,Dong Gyu Gang,Chung Choo Chung 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
Proportional-integral-derivative (PID) controls have been widely used for Sawyer motors. The electrical dynamics are generally neglected in general PIDs control since the electrical dynamics are faster than the mechanical dynamics. However, when the current control is used, the phase currents are reduced by back-emf and have the phase lags due to inductances. Thus, the electrical dynamics should be considered to improve the performance of PID control. In this paper, Lyapunov-based microstepping control of Sawyer motors with PID control is developed for improved performance of PID control. The proposed method consists of PID and Lyapunov-based controller. PID controllers make the desired forces and torque to track the position profiles of x and y with regulation of yaw. And the commutation scheme from the desired forces and torque to the desired phase currents are used. For the design of Lyapunov-based control, the stabilities of the equilibrium points are studied using Lyapunov method. Then, Lyapunov-based control is designed to compensate back-emfs and phase lags. Furthermore, the proposed method guarantees the exponential stabilities of desired currents for PID control. And, the closed-loop system is analyzed. The proposed method considering the electrical dynamics is designed without any coordinate transformation. Therefore, it could reduce the commutation delay. Simulation results show that the tracking performance of PID controller is improved by the proposed method.
Kim, Wonhee,Chen, Xu,Lee, Youngwoo,Chung, Chung Choo,Tomizuka, Masayoshi Elsevier 2018 Mechanical systems and signal processing Vol.104 No.-
<P><B>Abstract</B></P> <P>A discrete-time backstepping control algorithm is proposed for reference tracking of systems affected by both broadband disturbances at low frequencies and narrow band disturbances at high frequencies. A discrete time DOB, which is constructed based on infinite impulse response filters is applied to compensate for narrow band disturbances at high frequencies. A discrete-time nonlinear damping backstepping controller with an augmented observer is proposed to track the desired output and to compensate for low frequency broadband disturbances along with a disturbance observer, for rejecting narrow band high frequency disturbances. This combination has the merit of simultaneously compensating both broadband disturbances at low frequencies and narrow band disturbances at high frequencies. The performance of the proposed method is validated via experiments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In this paper, a discrete-time backstepping control algorithm is proposed for reference tracking of systems affected by both broadband disturbances at low frequencies and narrow band disturbances at high frequencies. </LI> <LI> A discrete time DOB, which is constructed based on infinite impulse response filters is applied to compensate for narrow band disturbances at high frequencies. </LI> <LI> A discrete-time nonlinear damping backstepping controller with an augmented observer is proposed to track the desired output and to compensate for low frequency broadband disturbances along with a disturbance observer, for rejecting narrow band high frequency disturbances. </LI> </UL> </P>
High Order Extended Observer Based Output Feedback Control for Unknown Nonlinear Systems
Wonhee Kim,Chung Choo Chung 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10
We propose a robust output feedback control to guarantee the semi-global uniform ultimate boundedness of the output tracking error using only output feedback for unknown nonlinear systems with external disturbance. The key idea of the proposed method is that the plant nonlinearities and external disturbance, and theirs derivatives are lumped into extended state variables. The high order extended observer (HOEOB) is developed to estimate the lumped extended state variables and full state. The benefit to using the HOEOB is that the estimation error can be reduced without increasing the bandwidth of the HOEOB. The backstepping controller is designed to guarantee the semi-global uniform ultimate boundedness of the output tracking error occurred by the disturbance estimation error. The performance of the proposed method is studied in both time and frequency domains. The effect of measurement noise to the estimation performance is also studied in the frequency domain. It is proven that very small estimation error is not necessarily required to obtain the precise output tracking using input-to-state stability (ISS) property.