• Journal of the Korea Society of Computer and Information
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• v.15 no.1
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• pp.91-102
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• 2010

It is very difficult that a previous surveillance system and vehicle detection system find objects on a limited and unstable illumination condition. This paper proposes a robust method of adaptively updating a reference background image for solving problems that are generated by the unstable illumination. The first input image is set up as the reference background image, and is divided into three block categories according to an edge component. Then a block state analysis, which uses a rate of change of the brightness, a stability, a color information, and an edge component on each block, is applied to the input image. On the reference background image, neighbourhood blocks having the same state of a updated block are merged as a block. The proposed method can generate a robust reference background image because it distinguishes a moving object area from an unstable illumination. The proposed method very efficiently updates the reference background image from the point of view of the management and the processing time. In order to demonstrate the superiority of the proposed stable manner in situation that an illumination quickly changes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.548-553
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• 2001

A new method to estimate the elastic-plastic J-integral and the crack tip opening displacement (COD) for circumferential through-wall cracked pipes under tension and under bending is proposed for Leak-Before-Break (LBB) analysis. Being based on the reference stress method with further modifications, the proposed method is simple to use and easy to be generalised in practice. Comparison of the CODs, predicted using the proposed method with published pipe test data show overall excellent agreement.

• Journal of Power Electronics
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• v.14 no.3
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• pp.549-563
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• 2014

In this paper, the speed regulation problem of permanent synchronous motor (PMSM) systems under the vector control framework is studied. A model reference adaptive controller (MRAC) based on the Lyapunov stability theory is first designed. Since the standard MRAC method provides poor disturbance rejection performance in the case of strong disturbances, a composite control method which combines the MRAC method and the disturbance estimation method, called the MRAC+ESO method, is proposed. An extended state observer (ESO) is introduced to estimate the lumped disturbances. The obtained estimated value acts as a feedforward compensation term to the MRAC controller. A stability analysis of the composite control method is given. Simulation and experimental results are presented and compared to show the effectiveness of the proposed control method.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.12
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• pp.60-69
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• 1997

We present an average method based on the multirate signal processing and dynamic allocation average for the purpose of monitoring event-related potentials(ERP) and continuously and dynamically. In the proposed method, first, latency shifts are detected through the cross correlation between a current response and the reference response. Then, the multirate signal processing which is composed of up-sampler, lowpass filter, and down sampler is performed to compensate the latency shifts of the reference response, therefore we obtain the reference response with a peak latencies compenated by those of a current response. Finally, the single response is obtained by averaging the compensated reference response and a current response. In the simulation, the results of quantitative evaluation by simulation and the results using linical data are presented. From the result, the proposed method reflects dynamic time-varying ERP more exactly than previous methods and is also effective in consecutive monitoring of ERP.

• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.435-442
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• 2001

According to the current increase of the usefulness of information in Internet, several methods are proposed in which multimedia information may be efficiently managed and retrieved. The purpose of this paper is to propose the new grouping method by SRR(Semantic Reference Relation) and DRR(Direct Reference Relation). The important point of this method proposed in this paper is to group MDI(Multimedia Document Informations) as a cluster of this multimedia objects. According to the result of experimental simulation, which has been tested by by the 1,000 multimedia items in internet, this method has made more efficiently the service and grouping of MDI possible than any other methods do in internet.

• Journal of Power Electronics
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• v.10 no.5
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• pp.528-537
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• 2010

A novel decision reference based method for the maximum power point tracking (MPPT) of PV arrays is presented in this paper. The proposed decision reference was derived from a simplified solar cell model. This method solves the problems of conventional MPPT algorithms, such as oscillation of the operating point at the steady state and confusion under rapidly changing insolation. It is shown by simulation and experimental results that the method properly tracks a rapidly changing insolation profile. The signal to noise ratio (SNR) of the new decision reference is also higher than those of conventional P&O and INC methods. An updating subroutine was included in the proposed MPPT algorithm to compensate for temperature and aging effects.

• Smart Structures and Systems
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• v.17 no.5
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• pp.725-742
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• 2016

This paper is focused on stiffness ratio effect and a new method to specify the best pattern of piezoelectric patches placement around a hole in a plate under tension to reduce the stress concentration factor. To investigate the stiffness ratio effect, some different values greater and less than unity are considered. Then a python code is developed by using particle swarm optimization algorithm to specify the best locations of piezoelectric actuators around the hole for each stiffness ratio. The results show that, there is a line called "reference line" for each plate with a hole under tension, which can guide the location of actuator patches in plate to have the maximum stress concentration reduction. The reference line also specifies that actuators should be located horizontally or vertically. This reference line is located at an angle of about 65 degrees from the stress line in plate. Finally two experimental tests for two different locations of the patches with various voltages are carried out for validation of the results.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.885-886
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• 2008

This paper presents a reference template design method for frame-based classification of underwater transient signals. In the proposed method, framebased feature vectors of each reference signal are clustered by using LBG clustering algorithm to reduce the number of feature vectors in each class. Experimental results have shown that drastic reduction of the reference database can be achieved while maintaining the classification performance with LBG clustering algorithm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2523-2532
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• 1994

In this paper, active noise control is performed in a duct system using the periodic pulse train which corresponds to the periodic component of noise source as a reference signal. Control algorithm applied in this study is possible to eliminate the acoustic feedback which occurs in the conventional filtered-x and filtered-u LMS algorithm by using electrical reference signal and has the fast adaptation speed with low filter orders by using synchronous sampling method is discussed via computer simulations and experiments of case studies such as frequency modulation, amplitude modulation and frequency differency between source signal and reference signal.

• Journal of Institute of Convergence Technology
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• v.2 no.1
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• pp.43-48
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• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.