• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.139.2-139
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• 2001

This paper presents identification and control of a surface mounting system. The mount head of the system is modeled to analyze its dynamic characteristics, which is critical to the placement performance of the mounter. Based on this model, an identification work is carried out to estimate the modeled parameters by using genetic algorithm (GA), which plays a role of minimizing an error between the actual response and the model response. Having obtained the identified parameters, we design a disturbance observer control to compensate the friction. The disturbance observer can estimate the friction force and the uncertainty of the system. From the experimental results, it is found that the proposed disturbance observer plus PID controller show a better performance than PID controller alone. In order to accomplish a stable contact content control for fast mounting a ...

• 한국소음진동공학회논문집
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• 제16권7호
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• pp.762-768
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• 2006

To address the need for new intelligent sensing of systems, this study presents a novel strain sensor based on piezoresistivity of carbon nanotube (CNT) and its nanocomposites. Fabrication and characterization of the carbon nanocomposite material are discussed and an electrical model of the CNT strain sensor was derived based on electrochemical impedance spectroscopy analysis and strain testing. The dynamic response of the sensor on a vibrating beam was simulated using numerical analysis and it was compared with experimental test. The simulation showed good agreement with the strain response of the actual sensor.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.9-12
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• 2008

There are many place of business in complex building, and recently claims of noise have increased in those buildings. It is most desirable reducing the noise problems to establish the noise criteria considering the noise source and the receiving place of business, which are derived from the dose-response of noise and results of the actual condition. The degree of response to the transmission noise could be changed with background noise level in the receiving stores. In this research, the subjective evaluation for three different background level in receiving place of business or rooms were investigated from subjective tests. The eight business sound source including aerobic music were used for the test.

• Structural Engineering and Mechanics
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• 제18권6호
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• pp.791-806
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• 2004

The inverse pseudo excitation method is used in the identification of random loadings. For structures subjected to stationary random excitations, the power spectral density matrices of such loadings are identified experimentally. The identification is based on the measured acceleration responses and the structural frequency response functions. Numerical simulation is used in the optimal selection of sensor locations. The proposed method has been successfully applied to the loading identification experiments of three structural models, two uniform steel cantilever beams and a four-story plastic glass frame, subjected to uncorrelated or partially correlated random excitations. The identified loadings agree quite well with actual excitations. It is proved that the proposed method is quite accurate and efficient in addition to its ability to alleviate the ill conditioning of the structural frequency response functions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.485-491
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• 2000

We obtain the mathematical model of the hard disk drive actuator system from the system response data of the finite element analysis or experimental results. System response data including the dynamics of the considered system are expressed as the mathematical model. It allows the dynamic analysis of the actuator system without resort to the repetitive finite element modeling work. Even though the dynamic characteristics of the system are affected somewhat by the structural modification and the change of the dynamic properties, we can use the modified size and material properties of the actuator system in the mathematical model to some extent. In this study, we express the mathematical model of the simplified rectangular plate first and then proceed to the actual hard disk drive actuator system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.145-148
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• 1990

In this paper, the problem of designing a feedback controller for a robotic manipulator, which is activated by a D.C. motor through a gear train and a flexible shaft or chain, is considered. When the response of the closed loop control system is relatively slow, a satisfactory controller may be designed as a PID controller. As the speed of the control system increases, however, the spring effect of the linkage becomes profound, and as a result, the transient response exhibits a substantial oscillation. To eliminate this oscillation, it is necessary to design the controller based on at least a fourth order system model. This, in turn, requires the feedback of the entire state variables. In practice, however, only the position of the manipulator and the velocity of the motor are readily measurable. The state variable reconstruction method or a state observer cannot be used because of the system nonlinearities such as the Coulomb frictions. In this study, an alternative controller, which is based on delayed feedback of the output variable only, is proposed, and a successful delayed feedback controller is designed and implemented on an actual experimental manipulator.

• 전기학회논문지
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• 제56권12호
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• pp.2240-2246
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• 2007

Optically coupled linear isolation amplifier requires special care to avoid oscillation in actual applications. In this paper methods to analyze the frequency characteristics of the amplifier are proposed to reveal the cause of oscillation and to provide design guidelines. The loop gain of the amplifier obtained through the equivalent circuit model shows that the phase margin is too small to ensure stable operations. Methods to get non-oscillatory response are proposed and the resulting frequency responses are analyzed. The common method adding a small capacitor to the amplifier is shown to degrade the frequency bandwidth. The frequency response of output voltage explains the need of filter capacitor in output stage. The usefulness of the method is verified through experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.912-913
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• 2008

In this paper, peak detector of generator output voltage and variable gain controller is introduced for the fast dynamic response. The general r.m.s. detecting signal of generator has inherent time delay from the actual signal. So the dynamic response of generator using conventional PID controller has some problem in sudden load change. In order to overcome this problem, the peak detector and signal selector with variable gain controller is used in this paper. The proposed control scheme is verified from experimental test of 200kW diesel engine-generator.

• Journal of Information Processing Systems
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• 제10권3호
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• pp.483-490
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• 2014

In today's world, communication, the sharing of information, and money transactions are all possible to conduct via the Internet, but it is important that it these things are done by the actual person. It is possible via several means that an intruder can access user information. As such, several precautionary measures have to be taken to avoid such instances. The purpose of this paper is to introduce the idea of a one-time password (OTP), which makes unauthorized access difficult for unauthorized users. A OTP can be implemented using smart cards, time-based tokens, and short message service, but hardware based methodologies require maintenance costs and can be misplaced Therefore, the quick response code technique and personal assurance message has been added along with the OTP authentication.

• Journal of Biosystems Engineering
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• 제21권2호
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• pp.155-166
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• 1996

A direct injection sprayer was designed using the concepts of injection mixing and total flow control, flowrate-based system compensating for the variation of forwarding speed. A metered rate, proportionally to the actual diluent flow rate, of a tracer chemical was injected directly into the diluent stream. The injection of chemical may improve the precision and safety of chemical application process. The control system was evaluated for the variables of the control interval, tolerances and sensitivities of flow regulation valve and injection pump. Performance of the system was assessed as that the response time of flow rate, response time of injection rate, absolute steady state error, and the coefficient of variance(C.V.) of concentration were 8.5 and -0.53 seconds, 0.067 lpm(0.8%) and 3.15%, respectively, at optimal parameters of control interval of 1.0 sec, fast sensitivity of flow regulation valve, medium sensitivity of injection pump and medium tolerance of flow rate. Performance of the system can be improved by increasing the sensitivity of flow regulating valve and employing a high resolution velocimeter, such as Doppler radar.