• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1641-1644
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• 2005

Magnetic actuation utilizes the mechanic torque that is the result of interaction of the current in a coil with an external magnetic field. A main obstacle is, however, that torques can only be produced perpendicular to the magnetic field. In addition, there is uncertainty in the Earth magnetic field models due to the complicated dynamic nature of the field. Also, the magnetic hardware and the spacecraft can interact, causing both to behave in undesirable ways. This actuation principle has been a topic of research since earliest satellites were launched. Earlier magnetic control has been applied for nutation damping for gravity gradient stabilized satellites, and for velocity decrease for satellites without appendages. The three axes of a micro-satellite can be stabilized by using an electromagnetic actuator which is rigidly mounted on the structure of the satellite. The actuator consists of three mutually-orthogonal air-cored coils on the skin of the satellite. The coils are excited so that the orbital frame magnetic field and body frame magnetic field coincides i.e. to make the Euler angles to zero. This can be done using a Neural Network controller trained by PD controller data and driven by the difference between the orbital and body frame magnetic fields.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.3
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• pp.283-289
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• 2016

In this study, electrochemical characterizations of PdCu/C catalysts that are synthesized by modified polyol method are investigated. Most of all, amount of ethylene glycol (EG) that is used as main component for catalyst synthesis is mainly modulated to optimize synthetic condition of the PdCu/C catalyst, For evaluations about catalytic activity and performance of direct formic acid fuel cell (DFAFC), half cell and full cell tests are implemented. As a result, when amount of EG is 4M, catalytic activities of the PdCu/C catalyst such as peak current of formic acid oxidation and active surface area are best, while maximum power density of DFAFC using the optimized PdCu/C catalyst is better than that using commercial Pd/C (30 wt%) by 6%. Based on that, PdCu/C catalyst synthesized by modified polyol method plays a critical role in improving (i) catalytic activity for formic acid oxidation and (ii) DFAFC performance by employing as anodic catalyst.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.579-589
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• 2008

In the past few years, there are many studies and researches of the underwater vehicles which are carried out its mission using sonar sensors. MSCL(Marine System Control Lab.) at Inha University developed test-bed small ROV, ISRO. ISRO is an open-frame type and has 4 thrusters. ISRO can control 4 motions i.e surge, sway, yaw and heave with sonar sensors. ISRO is developed for inspection of ship hull, marine structure, plant of lake or river and so on. When ROV ISRO inspects something, it is necessary to control the position of ROV ISRO's for the movement and anti-collision with structures in the underwater. In this paper, we deal with the development of a small ROV and verification of the position control system via simulation and experiment using sonar sensors.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.60.2-60
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• 2002

$\textbullet$ Contents 1: Introduction to nonlinear crane model $\textbullet$ Contents 2: Passivity of the crane model $\textbullet$ Contents 3: PD-Control based on the passivity $\textbullet$ Contents 4: Global regulation of the system without the velocity measurement $\textbullet$ Contents 5: Simulation studies for the performance test

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.104.4-104
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• 2002

$\textbullet$ Contents 1 : PD control of an elastic joint robot $\textbullet$ Contents 2 Dynamic output feedback law without velocity measurements $\textbullet$ Contents 3 : Robust analysis for parameter uncertainties of the robot system $\textbullet$ Contents 4 : Simulation studies with a three joint robot system $\textbullet$ Contents 5 : Performance comparison with an another control law

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.20-26
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• 2006

This study investigated on the conversion of nitrogen component in ammonia gas to control fuel-NOx. Control conditions were found to suppress the production of NOx in the catalytic combustion of the gasified fuels. Also, the results would provide the basis of the theoretical study on fuel-NOx generation mechanism.

• Advances in robotics research
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• v.2 no.3
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• pp.237-245
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• 2018

This study evaluates the efficacy of a class robust control scheme namely active force control in performing a joint based trajectory tracking of an upper limb exoskeleton in rehabilitating the elbow joint. The plant of the exoskeleton system is obtained via system identification method whilst the PD gains were tuned heuristically. The estimated inertial parameter that enables the AFC disturbance rejection effect is attained by means of a non-nature based metaheuristic optimisation technique known as simulated Kalman filter (SKF). It was demonstrated from the present investigation that the proposed PDAFC scheme outperformed the classical PD algorithm in tracking the prescribed trajectory both in the presence and without the presence of disturbance attributed by the mannequin limb weights (1 kg and 1.5 kg) that mimics the weight of actual human limb weight. Therefore, it is apparent from the results obtained from the present study that the proposed control scheme, i.e., PDAFC is suitable for the application of exoskeleton for stroke rehabilitation.

• Journal of Technologic Dentistry
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• v.8 no.1
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• pp.37-43
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• 1986

The purpose of this study is to evalute the effects of melting and casting procedures on the castability of some N-Cr and Ag-Pd alloys. One Ag-Pd alloy and two Ni-Cr alloys were chosen for study, and the first casting group of these alloys were used as the control, and with which the castability of the first recase group and the mixture group of the first recast and as much amount of the first casting alloy was compared. The results of this study were as follows: 1. The castability of the first recast alloys veried significantly depending upon the presence or abscence of the first casting alloy and the kind of alloys. 2. When the first recast alloy was mixed with as much amount of the first casting alloy, there was no significant difference in castabilityh between the first recast group and the first casting group. 3. When the first recast alloy was used alone, the castability veried significantly depending upon the kind of alloys, i.e., the castability of Rexillium III and Palliag M was decreased significantly when compared with that of the first casting groups, while that of C & B Alloy was not.

• Nutrition Research and Practice
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• v.11 no.2
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• pp.114-120
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• 2017

BACKGROUND/OBJECTIVES: A pivotal role of oxidative stress has been emphasized in the pathogenesis as well as in the disease progression of Parkinson's disease (PD). We aimed at investigating serum levels of antioxidant vitamins and elucidating whether they could be associated with the pathogenesis and progression of PD. MATERIALS/METHODS: Serum levels of retinol, ${\alpha}$- and ${\gamma}$-tocopherols, ${\alpha}$- and ${\beta}$-carotenes, lutein, lycopene, zeaxanthin and ${\beta}$-cryptoxanthin were measured and compared between 104 patients with idiopathic PD and 52 healthy controls matched for age and gender. In order to examine the relationship between antioxidant vitamins and the disease progression, multiple group comparisons were performed among the early PD (Hoehn and Yahr stage I and II, N = 47), advanced PD (stage III and IV, N = 57) and control groups. Separate correlation analyses were performed between the measured antioxidant vitamins and clinical variables, such as Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale (UPDRS) motor score. RESULTS: Compared to controls, PD patients had lower levels of ${\alpha}$- and ${\beta}$-carotenes and lycopene. ${\alpha}$-carotene, ${\beta}$-carotene and lycopene levels were significantly reduced in advanced PD patients relative to early PD patients and were negatively correlated with Hoehn and Yahr stage and UPDRS motor score in PD patients. No significant differences were found in serum levels of retinol, ${\alpha}$- and ${\gamma}$-tocopherols, and other carotenoids between PD patients and controls. No significant correlations were found between these vitamin levels and clinical variables in PD patients. CONCLUSTIONS: We found that serum levels of some carotenoids, ${\alpha}$-carotene, ${\beta}$-carotene and lycopene, were lower in PD patients, and that these carotenoids inversely correlated with clinical variables representing disease progression. Our findings suggest that decreases in serum ${\alpha}$-carotene, ${\beta}$-carotene and lycopene may be associated with the pathogenesis as well as progression of PD.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.6
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• pp.581-589
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• 2009

In a two-inertia motor system with flexible shaft, a torsional vibration is often generated as a quick speed response is required. This vibration makes it difficult to achieve a quick response of speed and disturbance rejection. The objective of this paper is to provide a systematic analysis and design of the three kinds of speed controllers such as I-P, I-PD, and state feedback control by using the weighted ITAE performance index. Some simulation and experiment results verify the effectiveness of the proposed design.