• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.296-300
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• 2003

The autopilot system targets decreasing labor, working environment improvement, service safety security and elevation of service efficiency. Ultimate purpose is minimizing number of crew for guarantee economical efficiency of shipping service. Recently, being achieving research about Course Keeping Control, Track Keeping Control, Roll-Rudder Stabilization. Dynamic Ship Positioning and Automatic Mooring Control etc. which compensate nonlinear characteristic using optimizing control technique. And application research is progressing using real ship on actual field. Relation of Rudder angle which adjusted by Steering Machine and ship-heading angle are non-linear. And Load Condition of ship as non-linear element that influence to Parameter of ship. Also, because the speed of a current and direction of waves, velocity and quantity of wind etc. that is disturbance act in non-linear from, become factor who make serv ice of shipping painfully. Therefore, service system of shipping requires robust control algorithm that can overcome nonlinearity. In this paper, Using fuzzy algorithm ,Design autopilot system of ship that could overcome the non-linear factor of ship and disturbance and examined result through simulation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.5
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• pp.51-58
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• 2010

This study was done to recommend a method for conserving the habitat of Amblyotropis verna grown naturally in campus of the Kyungpook National University at Daegu city. Vegetation characteristics and morphological characteristics of each individual were analyzed for the condition of the population at the growing season from May to June in 2010. Totally 11 vegetation data were collected and analyzed, and one vegetation community including Amblyotropis verna (Amblyotropis verna-Zoysia japonica community) was found. We found that the growing condition was not good with severe stamping and disturbance. The location-determining method by PCoA analysis showed the physical texture in soil was a critical factor determining the spatial distribution of the Amblyotropis verna-Zoysia japonica community. And the analysis of morphological characteristics found that light condition and soil hardness were the main ecological factor determining the size and form of each individual. Finally, this study recommend that minimizing impacts by human stamping and artificial disturbance and reducing the water stress were the best ways for the conservation of Amblyotropis verna habitats.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.8 s.101
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• pp.988-995
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• 2005

Vibration has been severly increased at the branch pipe of main steam header since the commercial operation of nuclear power plant. Intense broad band disturbance flow at the discontinuous region such as elbow, valve, and header generates the acoustical pulsation which is propagated through the piping system. The pulsation becomes the source of low frequency vibration at piping system. If it coincide with natural frequency of the pipe system, excessive vibration is made. High level vibration due to the pressure pulsation related to high dynamic stress, and ultimately, to failure probability affects fatally the reliability and confidence of plant piping system. This paper discusses vibration effect for the branch pipe system due to acoustical pulsations by broad band disturbance flow at the large main steam header in 700 MW nuclear power plant. The exciting sources and response of the piping system are investigated by using on-site measurements and analytical approaches. It is identified that excessive vibration is caused by acoustical pulsations of 1.3 Hz, 4.4 Hz and 6.6 Hz transmitted from main steam balance header, which are coincided with fundamental natural frequencies of the piping structure. The energy absorbing restraints with additional stiffness and damping factor were installed to reduce excessive vibration.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.705-715
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• 2007

Recently, the interest on power quality has been hot issue because the equipments cause voltage disturbance and have become more sensitive to the voltage disturbance. Additionally, the reseach on power electronic equipments applying to the high power has been increased. This paper deals with Line-Interactive Dynamic Voltage Restorer(LIDVR) system using 7-Level H-Bridge inverter, which is one of the solutions to compensate the voltage disturbance and to increase the power of equipments. The LIDVR has the following advantages comparing to the DVR with the series injection transformer. It has the power factor near to unity under the condition of normal source voltage, can compensate the harmonic current of the load and the instant interruption, and has the fast response. First, the construction, the operation mode and algebraic modeling of LIDVR are reviewed. And then the voltage control algorithm is proposed to get the sinusoidal load voltage with constant amplitude. Finally, simulation and experiment results verify the proposed LIDVR system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.4
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• pp.339-344
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• 2004

The purpose of this study was to evaluate neurosensory disturbance associated with implant surgery performed by implant practitioner (n=47) composed of trained oral surgeon, periodontist, prosthodontist. The incidence, type and duration of sensory disorder were investigated. Anatomical factor of the patient and experience of operator were also evaluated. The result revealed high incidence of inferior alveolar nerve damage (45%) regardless of experience of implant practitioner. The sensory disturbance sustained within 6 months for 61% of cases, which revealed almost normal recovery of nerve function. Initial neurologic sign after nerve damage was not coincide with their consequence of recovery. Half of the practitioners tried surgical intervention to the implants such as removing the fixture, partial unscrewing or re-implant shorter fixture, of which trial regarded as effective measure for 53% of cases. The result indicates that the objective method of sensory nerve evaluation should be introduced to the implant practitioners and the importance of informed consent for possibility of nerve damage in mandibular implant fixation.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.389-396
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• 2016

The sealing robot must be able to calculate the slope of a contact surface for complete adherence of the sealing on different concrete shapes. After the slope is obtained, the robot will track on the surface of the concrete, but this process contains an error in the actual purpose of the force command. The reason this a phenomenon occurs, the non-linearity of the contact surface and the end-effector, is due to parasitic coupling. Errors like make it difficult to measure accurately the respective factors. Therefore, it is regarded as a disturbance that occurs when it follows the work surface it. In this paper, we selected the friction coefficient of the surface as a control factor and designed a compensator to reduce effects of disturbance. Finally, in view of the non-linearity of the end-effector of a robot to contact surfaces directly, we propose a robust force tracking controller in the finite range for managing disturbances that occur during the sealing.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.867-872
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• 2022

The effect of load is an important factor in precise speed control of a motor. n this study, we design a state observer that can estimate and define one state of disturbance including errors and nonlinear terms of mathematical models, which is not easy with a mathematical model. Then, the observation gain is set so that the estimation error of the state observation converges to 0, and the estimated state is used in the back stepping controller to design a controller capable of precise speed tracking. As a result of applying to 1 [hw] class Interior Permanent Magnet Synchronous Motor, excellent stste variable observation and tracking performance can be confirmed.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.369-372
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• 1994

In this paper, a voltage type dual PWM converter which achives the bidirectional power flow between a AC supply and a DC bus voltage is described. In PWM modulator, there exist a time difference between the sampling time and carrier wave, it achieves stable modulation even the disturbance in the synchronous AC source voltage. And this paper proposes the compensation method and the control method related a disturbance of synchronous signal using the low pass filter and phase shifter for the stable modulation. As a result the voltage type dual PWM converter makes the imput current wave as sinusoid, and performs the high power factor driving.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.586-591
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• 2004

A load/unload mechanism is applied to most small form factor hard disk drives. Loading velocity is ones of the most important factors to ensure the reliability of the load/unload operations. Especially, the lower the flying height of the head becomes, the more important the accuracy of the loading velocity control becomes. Because there is no sensor during the load/unload operations, BEMF voltage is used to sense the head velocity. To measure BEMF voltage, a simple circuit is added to the load/unload HDD control system. Overall acceptable results are obtained by using the simple PI controller but the errors from the target velocity occur when the head moves along the ramp and then reaches the disk. Feedforward profile and disturbance observer are used to remove those errors effectively.

• Journal of East-West Nursing Research
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• v.5 no.1
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• pp.65-74
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• 2000

This study was attempted to show basic data for search of nursing intervention about sleep improving in home and institute elderly peoples. Research design was cross-sectional survey method for comparison of sleep patterns and another variables between home and institute elderly peoples. Subjects were sampled by purpose as home and institute elderly peoples at age of 65 or older in Seoul or nearly. The survey questionnaire was used by modification of sleep questionnaire which Kim, O, Song & Bak(1997) developed. Data were collected between December, 1999 and April, 2000. And data were analyzed by SPSS PC+ for purpose of research. Results are as follows: 1. Home and institute elderly peoples, all were change of sleep patterns and sleep pattern was showed early sleeping down. But institute elderly peoples slept earlier than home elderly peoples. 2. As rest of morning, difficulty of falling asleep and disturbance of re-asleep, subjective thinking and feeling were showed more negative thing home elderly peoples than institute elderly peoples. As frequency of falling asleep within 5 min in 1 week, frequency of falling asleep over 30 min in 1 week and frequency of awakening in a day, objective frequency were showed more insomnia institute elderly peoples than home elderly peoples. Home elderly peoples didn't nap most and institute elderly peoples napped on very short time. 3. Regarding sleep-disturbing factors, physical factor was popularly joint-disturbance in all, home and institute elderly peoples. Environmental factor was popularly noise, particularly institute elderly peoples. Emotional factor wasn't all. 4. Practiced strategies for better sleep was popularly TV/Radio in home elderly peoples and were popularly regular sleep and religious action in institute elderly peoples. From the results of this study, home elderly peoples need nursing intervention of improving self-satisfaction on sleep and institute elderly peoples need nursing intervention of decreasing falling asleep-disturbing and decreasing frequency of awakening in sleep.