• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.554-560
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• 2006

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include: (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2502-2507
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• 2003

In this paper, a crack sealing robot is developed. The crack sealing robot is built to detect, track, and seal the crack on the pavement. The sealing robot is required to brush all dirt in the crack out for preparing a better sealing job. Camera calibration has been done to get accurate crack position. In order to perform a cleaning job, the explicit force control method is used to regulate a specified desired force in order to maintain constant contact with the ground. Experimental studies of force tracking control are conducted under unknown environment stiffness and location. Crack tracking control is performed. Force tracking results are excellent and the robot finds and tracks the crack very well.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.963-968
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• 2002

In this work, porous silicon (PS) layer is investigated as a sensing material to detect organic vapors such as ethanol (called alcohol), methanol, and acetone in low concentrations. To do this, PS sensors were fabricated. They have a membrane structure and comb-type electrodes were used to detect the change of electrical resistance effectively. PS layer on Si substrates was formed by anodization in HF solution of 25%. From fabricated sensors, current-voltage (Ⅰ-Ⅴ) curves were measured for gases evaporated from 0.1 to 0.5% organic solution concentrations at 36$\^{C}$. As the result, all curves showed rectifying behavior due to a diode structure between Si and the PS layer. The conductance of most sensors increased largely at high voltage of 5V, but the built-in potential on the measured Ⅰ-Ⅴ curve was lowered inversely by the adsorption effect of the organic vapors with high dipole moment.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.108-117
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• 2004

In this paper, a measuring NDT(nondestructive testing) system using RUS(Resonant Ultrasound Spectroscopy) was built for nondestructive evaluation of the flaw in a ceramic Ferrule. The principle of RUS is that the mechanical resonant frequency of the materials depends on density, and the coefficient of elasticity. The RUS system is the measuring which is to exite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen which has some defects. RUS system is configured of spectrum analyzer, power amplifier, PZT sensor and support frame. For defect evaluation by the RUS, we performed to measure natural frequency of Ferrule, both acceptable and cracked. In the case of Ferrule, the resonant frequency of cracked-Ferrule existed to higher frequency band than acceptable-Ferrule.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2076-2078
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• 2002

This paper presents an Intelligent Balance Beam Controller(IBBC) which can estimate the inertia of load automatically. Balance Beam controller is a kind of construction tool which can control the attitude of the load hanging in the air such as a beam carried by crane. In our previous work, Balance Beam had been built to control the object in air using a mechanical gyro system having a position controllable gimbal structure. In field application the load inertia for operation is not easy to figure out because the weight and shape which determines the inertia, varies depending on the object to be carried. Therefore it is difficult for a worker to operate a Balance Beam and an accident could be caused occasionally. We designed an automatic load estimator to measure the inertia of arbitrary load by using an angular velocity sensor that is installed on the Balance Beam. Simulation results and current status for implementation are presented.

• Journal of the Korea Safety Management & Science
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• v.20 no.1
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• pp.33-40
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• 2018

The rate of fire in buildings is gradually increasing in these days and the damage of property are severely increasing. This study suggests a methodology that provides information of the emergency exits based on indoor location services. The methodology uses determination technology and the latest update of indoor map generation via the built-in sensors of smartphone. This paper enhances the accuracy of indoor localization, and also it is to study how to provide exact indoor layout for rescuing the workers in emergency, such as fires and natural disasters.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.53.3-53.3
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• 2021

Adaptive Optics (AO) was first studied in the field of astronomy, and its applications have been extended to the field of laser, microscopy, bio, medical, and free space laser communication. AO modelling and simulation are required throughout the system development process. It is necessary not only for proper design but also for performance verification after the final system is built. In KASI, we are trying to develop the AO Python Package for AO modelling and simulation. It includes modelling classes of atmosphere, telescope, Shack-Hartmann wavefront sensor, deformable mirror, which are the components for an AO system. It also includes the ability to simulate the entire AO system over time. It is being developed in the Super Eye Bridge project to develop a segmented mirror, an adaptive optics, and an emersion grating spectrograph, which are future telescope technologies. And it is planned to be used as a performance analysis system for several telescope projects in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1106-1111
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• 2007

This paper is focused on design of a new active control engine mount (ACM), which is compact in size and cost effective. The ACM, consisting of an electrodynamic actuator as the active element, flat springs and a sliding ball joint, is different in structure from the previous ACM designs based on the conventional hydraulic engine mount. Dynamic characteristics of the proposed ACM are extensively investigated before a prototype ACM, which meets the design specifications, is built in the laboratory. For cost effectiveness, a feed-forward control algorithm without a feedback sensor is used for reduction of the transmitted force through the ACM from the engine. The prototype ACM is then harmonic-tested with a rubber testing machine for verification of its control performance as well as adequacy of modeling. Experimental results show that the proposed ACM is capable of reducing the transmitted force by 20 dB up to the frequency range of 60 Hz.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.10
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• pp.53-66
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• 1994

In this paper, a fuzzy expert system is developed for fault diagnoisis of a drum-type boiler system in fossil power plants. The develped fuzzy espert system is composed of knowledge base, fuzzification module, knowledge base process module, knowledge base management module, inference module, and linguistic approximation module. The main objective of the fuzzy expert system is to check the states of the system including the drum level and detect faults such as the feedwater flow sensor fault, feedwater flow control valve fault, and water wall bube rupture. The fuzzy expert system diagnoses faults using process values, manipulated values, and knowledge base which is built via interviews and questionaries with the experts on the plant operations. Finally, the validity of the developed fuzzy expert system is shown via experiments using the digital simulator for boiler system is Seoul Power Plant Unit 4.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.5
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• pp.415-425
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• 2000

An open architecture manufacturing strategy intends to integrate manufacturing components on a single platform so that a particular component can be easily added and/or replaced. Therefore, the control scheme based upon the open architecture concept is hardware-independent. In this paper, a modular and object oriented approach for a PC-based open robot control system is investigated. A standard reference model for robot systems, which consists of three modules; hardware module, operating system module, and application software module, is first proposed. Then, a PC-based Open Robot Controller(PC-ORC), which can reconfigure robot control systems in various production environments, is developed. The PC-ORC is built upon the object-oriented method, and allows an easy implementation and modification of various modules. The PC-ORC consists of basic softwares, application objects, and additional hardware device on the PC Platform. The application objects are: sequencer, computation unit, servo control, ancillary equipment, external sensor control, and so on. In order to demonstrate the applicability of the PC-ORC, the proposed PC-ORC configuration is applied to an industrial SCARA robot system.