• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.279-282
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• 2004

This paper presents load torque observer that is used to deadbeat load torque observer in the induction motor position control system. The simulation has been obtained by simulink. A digital control is composed by trigger method in the continuous block diagram. The results show that proposed system has good effectiveness for the disturbance in induction servo motor system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.247-249
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• 2008

There are many types of grid-connected inverter controllers; Synchronous Reference Frame (SRF)-based controller is the most popular methods. SRF-based controller is capable for reducing both of zero-steady state error and phase delay. However, SRF-based controller has a complex algorithm to apply in real application such as digital processor. Resonant controller is also reduced zero-steady state error, but its transfer function has a high order. In this paper, a simple proportional control is applied for grid connected inverter with LCL filter. LCL filter is a third order system. Applying a simple proportional controller is not increased the order of closed loop transfer function. By this technique, the single phase model is easily obtained. To reduce steady state error, proportional gain is set as high as possible, but it may produce instability. To compromise between a minimum steady state error and stability, the single phase model is evaluate through Root Locus and Bode diagram. PSIM simulation is used to verify the analysis.

• 천문학회보
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• 제35권2호
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• pp.81.1-81.1
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• 2010

We present a study of five open clusters (Alessi 53, Berkeley 49, Berkeley 84, Czernik 5, Pfleiderer 3) based on ugriz images of the Sloan Digital Sky Survey (SDSS). Physical properties of these clusters are not yet well known. The center and size of these clusters are determined using the radial number density profile. Using the proper motion data, we select the members of the target clusters. We estimate physical parameters of the clusters based on the isochrone fitting in the Color-Magnitude Diagram (CMD) : reddening, distance, and age. The foreground reddening is determined to be E(B-V)=0.71-1.55 mag. The distances to target clusters are derived to be 2.0-4.4 kpc, corresponding to the galactocentric distances of 7.5-11.9 kpc. Their ages are in the range of 280 to 1000 Myr. Their spatial distribution in our Galaxy is similar to that of other intermediate-age open clusters. We find ten blue straggler star candidates in Berkeley 49. This number of blue stragglers is a typical value for the age of Berkeley 49.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.136-136
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• 2000

The direct drive servo valve(DDV) is composed of a DC rotor, link, valve spool and displacement sensor(LVDT) where the spool is directly coupled to the DC motor through the link. Since the DDV is a kind of one-stage valve, the robust controller is required to overcome the flow force effect on the spool motion. The mathematical equations are derived and the stability, accuracy and response speed of a DDV are investigated analytically using a linearized system block diagram. Proportional control, PID control. Time-Delay control, Sliding Mode control, and Proportional control using the load pressure are applied to DDV to find which one shows the best control performance. The digital computer simulation results show that the proportional control using the load pressure satisfies the design requirement of response speed and steady state error regardless of the variation of load pressure,

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 영호남 학술대회 논문집
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• pp.76-80
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• 2003

Recently as new digital media like High Definition Television (HDTV) have been made popularization. However In case of image quality characteristics of AC PDP, the problem especially raised is 'image sticking' phenomenon, the phenomenon that the previously displayed pattern still remains after the image in realizing high picture quality. In this paper, Image sticking Phenomena observed in AC PDP are defined and classified, these effects are analyzed as luminance, color purity through chromaticity diagram and firing voltage state using light waveform.

• Geomechanics and Engineering
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• 제9권2호
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• pp.169-193
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• 2015

This paper is the second part of the study for determining the seismic behavior of soil systems. The aim of this part is to present solution approaches for determining seismic site amplification. For this purpose, two solution techniques are used. The first technique is equivalent linear analysis which is mostly used in literature. The other technique is real time parameter updating approach and this approach uses the possibilities of Simulink effectively. A graphical user interfaced (GUI) program called DTASSA standing for Discrete-Time Analysis of Seismic Site Amplification is developed. In DTASSA, automatic block diagram producing system is developed and seismic site amplification for multiple soil layers may easily be investigated in real time. Numerical applications have been carried out to check the reliability of developed algorithm. The results of DTASSA are compared with SUA, EERA and NERA programs for the particular example problems.

• 천문학회보
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• 제36권1호
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• pp.58.1-58.1
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• 2011

We present elemental abundances of 95 blue compact dwarf galaxies (BCDs) at z=0.2~0.35 using the Sloan Digital Sky Survey (SDSS) DR7. We derived element abundances using Te method. We found that nitrogen abundance of merging BCDs are more enriched than normal BCDs by fast rotating young massive star. On the other hand, neon and oxygen abundances for merging BCDs are slightly lower than the normal BCDs. This might be result from the dilution by metal-poor gas infall during the interaction. This means that merging BCDs undergone star formation event for a long time than normal BCDs and we trying to explain using STARLIGHT code and various star formation rates (SFRs) ratios. At a result, merging BCDs have older stellar population (>10 Myr) more than normal BCDs and have clear distinction in elements abundances versus Ha/UV diagram. We also discuss the characteristics of post merger candidate using FUV to NUV ratios.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 제2회 박판성형심포지엄 논문집 박판성형기술의 현재와 미래
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• pp.171-182
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• 1998

An automated surface-strain measuring system using the image processing technique is developed in the present study, which consists of the hardware to capture and to display digital images, and the software to calculate the 3D informations of grid points from two views. New or improved algorithms the mapping and establishing correspondence of grid points and elements, the camera calibration, and the subpixel measurement of grid points, are implemented. As an application of the present system the surface-strains of deformed blanks in the limitting dome height test, the square cup deep-drawing and punch stretching to obtain the forming limit diagram are measured. The results are compared with those obtained by conventional manual methods.

• 소성∙가공
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• 제7권6호
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• pp.575-585
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• 1998

An automated surface-strain measuring system using the image processing technique is developed in the present study which consists of the hardware to capture and to display digital images. and the software to calculate the 3-D informations of grid points from two views. New or improved algorithms for the mapping and establishing correspondence of grid points and elements the camera calibration and the subpixel measurement of grid points are implemented. As an application of the present system the surface-strains of deformed blanks in the limitting dome height test the square cup deep-drawing and punch stretching to obtain the forming limit diagram are measured. The results are com-pared with those obtained by conventional manual methods.

• 한국멀티미디어학회논문지
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• 제22권1호
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• pp.18-26
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• 2019

In this paper we propose how to detect circular objects in the gray scale image and segment them using the discrete Morse theory, which makes it possible to analyze the topology of a digital image, when it is transformed into the data structure of some combinatorial complex. It is possible to get meaningful information about how many connected components and topologically circular shapes are in the image by computing the persistent homology of the filtration using the Morse complex. We obtain a Morse complex by modeling an image as a cubical cellular complex. Each cell in the Morse complex is the critical point at which the topological structure changes in the filtration consisting of the level sets of the image. In this paper, we implement the proposed algorithm of segmenting the circularly shaped objects with a long persistence of homology as well as computing persistent homology along the filtration of the input image and displaying in the form of a persistence diagram.