• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.180-185
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• 2003

Performance test of servo control system that is used ultra-precision positioning system with single plane X-Y stage is performed by simulation with Matlab. Analyzed for previous control algorithm and adapted for modem control theory, dual servo algorithm is developed by minimum order observer, and stability priority on controller are secured. Through the simulation and experiments on ultra precision positioning, stability and priority on ultra-precision positioning system with single plane X-Y stage and control algorithm are secured by using Matlab with Simulink and ControlDesk made in dSPACE

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.429-429
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• 2000

Micro positioning mechanism is the key technology in many fields, such as scanning electron microscopy (SEM), x-ray lithography, mask alignment and micro-machining. In the paper, a 3DOF parallel-type micro-positioning mechanism is proposed. This mechanism uses piezo-actuators and Flexure hinge to control x, y and $\theta$ motion. It is shown both analytically and numerically that 2 DOF flexure hinge model was better precision than 1 DOF flexure hinge design.

• 동력기계공학회지
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• 제16권2호
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• pp.66-74
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• 2012

In this paper, the authors propose a new approach to control a barge type surface vessel. It is based on the Dynamic Positioning System(DPS) design. The main role of barge ship is to carry and supply the materials to the floating units and other places. To carry out this job, it should be positioned in the specified area. However sometimes the thrust systems are installed on it, and in general the rope control by mooring winch system is used. It may be difficult to compare the control performances of two types. If we consider this problem in point of usefulness, we can easily find out that the winch control system is more useful and applicable to the real field than the thrust control system except a special use. Therefore, in this paper we consider a DPS design problem which can be extended to the many application fields. The goal of this paper is twofold. First, the sliding mode controller (SMC) for positioning the our vessel is proposed. Especially, in this paper, a robust stability condition is given based on descriptor system representation. In the result, the sliding mode control law guarantees to keep the vessel in the defined area in the presence of environmental disturbances. And second, the thrust allocation problem is solved by using redistributed pseudo-inverse (RPI) algorithm to determine the thrust force and direction of each individual actuator. The proposed approach has been simulated with a supply vessel model and found work well.

• 제어로봇시스템학회논문지
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• 제22권2호
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• pp.75-82
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• 2016

Visible light communication (VLC) using LED lamps is suitable for implementing an indoor positioning system in an indoor environment where the global positioning system (GPS) signal does not reach. In this paper, we present an indoor positioning system for mobile robots using a VLC beacon and fuzzy rules. This system consists of an autonomous mobile robot, VLC modules, and device application software. Fuzzy rules are applied to plan the global and local paths along which the mobile robot navigates indoors. The VLC transmitter modules are attached to the wall or the ceiling as beacons to transmit their own location information. The variable pulse position modulation (VPPM) algorithm is used to transmit data, which is a new modulation scheme for VLC providing a dimming control mechanism for flicker-free optical communication. The mobile robot has a receiver module to receive the location information while performing its mission in the environment where VLC transmitters are deployed.

• Child Health Nursing Research
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• 제28권1호
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• pp.70-81
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• 2022

Purpose: This study aimed to develop and evaluate the effectiveness of an educational program on developmental positioning (EPDP) for nurses in neonatal intensive care units (NICUs). Methods: The study utilized a non-equivalent control group pretest-posttest design. Sixty NICU nurses were recruited from two university hospitals in Daejeon, South Korea. The EPDP consisted of a 7-week program: 3 weeks of education and practice, followed by 4 weeks of encouragement messages using social networking services. Developmental positioning (DP) posters and DP aids were also provided during the intervention period. The intervention group (n=30) received the EPDP, but not the control group. The data were analyzed using the 𝜒² test, the Fisher exact test, the independent t-test, and repeated-measures analysis of variance. Results: Participants' knowledge (t=7.49, p<.001), attitudes (t=1.99, p=.001), self-efficacy (t=2.99, p=.004), performance of DP (t=2.98, p=.004) and Infant Positioning Assessment Tool (IPAT) scores (F=29.50, p<.001) were significantly higher in the intervention group than in the control group. Conclusion: The EPDP can be an effective and useful program for improving the performance of DP among NICU nurses by increasing their knowledge, attitudes, and self-efficacy of DP. However, further research involving various NICU settings is needed to gather more empirical evidence.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.429-434
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• 2002

In order to improve the accuracy in the field of simiconductor and LCD research equipment, the demand of XYZ stage which is possible to control X axis, Y axis and Z axis has been increased steadly in place of the existing XY stage which is only practicable to X & Y axis positioning control. This paper presents a new pneumatic actuator for Micro-positioning control in the XYZ stage. Air pressure in a pneumatic actuator is controlled by the E/P Regulator. The control range of pneumatic actuator is about 100 micro-meters and it's construction concept is easy to apply a practical state

• 한국해양공학회지
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• 제10권3호
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• pp.153-161
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• 1996

This paper presents a design method of dynamic positioning control system for floating platform with rotatable and retractable thruster using $H_{\infty}$ control technique. The norm band of uncertainty is captured by multiplicative perturbation between nominal model and reduced order model. A controller robust to the uncertainty is designed applying $H_{\infty}$ synthesis. The control law satisfying robust stabillity and nominal performance condition is determined through the mixed sensitivity approach. The evaluation for the resultant controller obtained by $H_{\infty}$ synthesis is done through simulations of the closed loop system. The results of $H_{\infty}$ synthesis are compared to those of the traditional LQ synthesis method.

• 한국정밀공학회지
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• 제17권12호
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• pp.9-15
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• 2000

• 대한전기학회논문지:전력기술부문A
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• 제48권2호
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• pp.159-167
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• 1999

A digital tracking controller is proposed for a precise positioning control under a large repetitive and/or non repetitive disturbances. The proposed control system. Numerical Examples are illustrated for a precise head positioning of optical disk drives regardless of a torque disturbance and/or output disturbance.

• 대한토목학회논문집
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• 제11권4호
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• pp.151-162
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• 1991

본 연구에서는 자료형태 및 전처리수준이 다른 위성영상자료를 이용하여 전처리수준에 따른 외부표정요소의 최적다항식형태와 위치결정정확도를 파악하고, 지상기준점의 획득방법 및 획득방법에 따른 3차원 위치결정정확도를 분석함으로서 SPOT 위성영상을 이용한 3차원 위치결정이론 및 프로그램을 개발하고 위치결정의 정확도를 향상시키는데 목적이 있다. 본 연구수행 결과 각 전처리수준에 대한 외부표정요소의 최적다항식형태(수준 1B; 15변수, 수준 1AP, 1A; 12변수)를 결정할 수 있었으며, 전처리수준에 따른 위치결정 정확도분석에서는 수준 1AP 위성사진의 정확도가 가장 좋았으나, 수치영상인 수준 1A도 유사한 정확도를 나타냄을 알 수 있었다. 또한, 지상기준점의 획득방법이 다른 수준 1A 수치영상의 3차원 위치결정 정확도를 분석한 결과, 지상기준점의 정확도가 양호한 경우 부가매개변수의 도입만으로 정확도 향상률이 큰 반면 지상기준점의 정확도가 저하되는 경우 부가매개변수의 도입만으로 정확도가 크게 향상되지 않아 조정체계에 과대오차소거이론이 포함된 동시조정이론을 적용함이 바람직함을 알 수 있었다.