• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.988-991
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• 2003

In this paper, we try to develop the controller which uses the block diagrams of SIMTool and internal functions CEMTool for planning the global driving controller for high efficiency AGV. We acquire the control efficiency by controlling the motor used each part of AGV driving controller. The block diagram structures provided with SIMTool is easily designed by the controller, and the monitoring and analysis of the results is researched by simulation. We expect to control AGV. robot and various plant using Ziegler-Nichols auto-tuning method and external I/O board

• Journal of the Optical Society of Korea
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• 제4권2호
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• pp.94-99
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• 2000

Optical monitoring using the chromatic aberration of focusing optics is applied to auto-focus control in laser welding. The spectral transmittance of thermal radiation from a weld pool through an aperture depends on the wavelength of the spectral band and on the distance of the weld pool from the focusing optics. Its dependence has been used to monitor the focus shift in laser welding by measuring the spectral band signals filtered by the aperture. The difference between pulsed and continuous laser welding is analyzed. Furthermore, the dependence of the focus shift monitoring on the weld pool size variation is optimized to monitor the focus shift independently from the laser power change at the weld pool. The performance of the auto-focus control with chromatic filtering is presented for pulsed laser welding.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2584-2586
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• 2000

A drum level control is one of the most important control systems in thermal power plant. The control objective of drum level of boiler in thermal power plant is to maintain drum level at constant set-point regardless of disturbance such as main steam flow. The implemented drum level controller is the cascade PI controller. The important factor in drum level controller is the parameters of two PI controllers. The tuning of PI controller parameter is tedious and time-consuming job. In this paper, the relay feedback Ziegler - Nichols tuning method extended to auto-tune cascade PI drum level controller. Finally, the simulation result using boiler model in Power Plant shows the validity of auto-tuned cascade PI controller.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.454-458
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• 2008

This article describes an interference reduction scheme for Mobile WiMAX in an indoor environment. The feasibility of user deployed femtocells in the same frequency channel as an existing macro cell network is investigated. One of the important requirements for co-channel operation of femtocells such as auto-configuration and self optimization are discussed. In femtocell deployments, leakage of the pilot signal to the outside of a house can result of the higher number of mobility events caused by passing user of macrocell. This interference effect can be minimized by reducing the pilot power using proper scheme. This paper introduces existing auto-configuration method of power control and proposed interference reduction scheme using power control for Mobile WiMAX in an indoor environment.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.701-706
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• 1998

A design method of rule -based fuzzy modeling is presented for the model identification of complex and nonlinear systems. The proposed rule-based fuzzy modeling implements system structure and parameter identification in the efficient form of " IF..., THEN,," statements. using the theories of optimization and linguistic fuzzy implication rules. The improved complex method, which is a powerful auto-tuning algorithm, is used for tuning of parameters of the premise membership functions in consideration of the overall structure of fuzzy rules. The optimized objective function, including the weighting factors, is auto-tuned for better performance of fuzzy model using training data and testing data. According to the adjustment of each weighting factor of training and testing data, we can construct the optimal fuzzy model from the objective function. The least square method is utilized for the identification of optimum consequence parameters. Gas furance and a sewage treatment proce s are used to evaluate the performance of the proposed rule-based fuzzy modeling.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2007년도 International Conference
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• pp.184-189
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• 2007

Concerns about food safety continue to rise and under this situation, governments of some countries have reinforced their regulations more strictly for food safety. In order to prevent food safety incidents or, at least to minimize the impact, the preparedness is very important. As a consequence of this, traceability system has become an essential tool for food safety. Recently, it requires more prevention-based food safety control system. One of the most generally used systems for food safety control is Hazard Analysis and Critical Control Point (HACCP). Both traceability and HACCP systems can be integrated through Electronic Product Code (EPC) Sensor Network technologies which have four value propositions. In this paper, we will introduce the concept of product and process traceability system (P2TS) through the integration of three systems to improve food safety management. The final aim is to find out the added values of the P2TS.

• 한국해양공학회지
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• 제27권6호
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• pp.56-64
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• 2013

Crabbing motion is the pure sway motion of a ship without surge velocity. Thus, it can be applied to a berthing operation. Crabbing motion is induced by a peculiar operation method called the push-pull mode. The push-pull mode is induced by using a combination of the main propeller and side thruster. Two propellers generating the same amounts of thrust and rotating in opposite directions produce some yawing moment on a vessel but do not induce longitudinal motion. With the additional operation of side thrusters, the push-pull mode is used to induce a large amount of lateral force. In this paper, three-degree-of-freedom equations of motion such as for the surge, sway, and yaw are constructed for the crabbing motion. Based on these equations of motion, a feedback linearization control method is applied to auto-berthing control for a twin-screw ship with side thrusters. The controller can deal with the nonlinearity of a system, which is present in the berthing maneuver of a twin screw ship. A simulation of the auto-berthing of a ship is performed to validate the performance of the designed controller.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권1호
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• pp.98-118
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• 2014

An auto weather-vaning system for a Dynamic Positioning (DP) vessel is proposed. When a DP vessel is operating, its position keeping is hindered by ocean environmental disturbances which include the ocean current, wave and wind. Generally, most ocean vessels have a longitudinal length that is larger than the transverse width. The largest load acts on the DP vessel by ocean disturbances, when the disturbances are incoming in the transverse direction. Weather-vaning is the concept of making the heading angle of the DP vessel head toward (or sway from) the disturbance direction. This enables the DP vessel to not only perform marine operations stably and safely, but also to maintain its position with minimum control forces (surge & sway components). To implement auto weather-vaning, a nonlinear controller and a disturbance observer are used. The disturbance observer transforms a real plant to the nominal model without disturbance to enhance the control performance. And the nonlinear controller deals with the kinematic nonlinearity. The auto weather-vaning system is completed by adding a weather-vaning algorithm to disturbance based controller. Numerical simulations of a semi-submersible type vessel were performed for the validation. The results show that the proposed method enables a DP vessel to maintain its position with minimum control force.

• 방송공학회논문지
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• 제5권2호
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• pp.239-246
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• 2000

본 논문에서는 입체 카메라의 자동 초점 제어에 필요한 제어 변수 추출 방법을 제안한다. 일반적으로 카메라로 획득한 입체 영상에서 관심 있는 피사체가 영상의 중심부에 있다고 가정을 한다. 이 경우에 획득된 영상에서 특정한 크기의 중심 영역에 대해서만 2D 웨이블릿 변환을 한다. 변환을 거친 신호 중에서 고역 성분 (HH)에 대한 Ll Norm을 이용하여 필요한 초점제어 변수를 추출한다. 실험결과를 통해 제안된 방식이 기존의 DCT를 이용한 방식에 비해 입체카메라의 자동 초점 제어에 효과적으로 적용될 수 있음을 보인다.

• 한국조명전기설비학회지:조명전기설비
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• 제7권4호
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• pp.42-50
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• 1993

본 연구에서는 자동동조 퍼지 PID 제어 앨고리즘을 사용하여 유도전동기 구동방법을 제안하였다. 퍼지제어에서는 수학적인 모델링이 없이 경험적인 정보를 이용하면 제어가 가능하며 퍼지룩업 테이블을 적절히 이용하면 실시간 제어도 가능한 것이 특징이라 볼 수 있다. 또한, 퍼지규칙을 몇 개의 영역으로 구획하여 시스템의 변화가 발생되고, 또 파라미터의 변화가 유도 전동기 구동 특성에 크게 영향을 주는 것을 감안, 본 시스템의 고성능, 고정도제어를 위하여 퍼지 앨고리즘을 적용하여 파라미터가 자동동조 기능을 갖는 유도전동기의 구동 시스템을 설계, 제작하였으며 그 특성을 기존의 PID 제어방식과 비교하였다.