• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.769-772
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• 1998

This paper present an efficient techniques for visual inspection of taped electronic parts, suitable for real time implementation. The main environments of developed system are IBM-compatible personal computer, frame grabber, digital input-output board. It is connected to the programmable logic controller unit of the taping machine in real time. Using a queuing structure, operator or extractor machine can remove easily the defect one from production line. Also, we design a new illumination system for sacquring shape and subface features of object. Therefore, it redue pre-processing step and processing time.

• ETRI Journal
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• 제23권1호
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• pp.16-22
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• 2001

Efficient quantization methods of the line spectrum pairs (LSP) which have good performances, low complexity and memory are proposed. The adaptive quantization range method utilizing the ordering property of LSP parameters is used in a scalar quantizer and a vector-scalar hybrid quantizer. As the maximum quantization range of each LSP parameter is varied adaptively on the quantized value of the previous order's LSP parameter, efficient quantization methods can be obtained. The proposed scalar quantization algorithm needs 31 bits/frame, which is 3 bits less per frame than in the conventional scalar quantization method with interframe prediction to maintain the transparent quality of speech. The improved vector-scalar quantizer achieves an average spectral distortion of 1 dB using 26 bits/frame. The performances of proposed quantization methods are also evaluated in the transmission errors.

• ETRI Journal
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• 제30권2호
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• pp.290-300
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• 2008

We apply IEEE 802.3 frame burst mode (FBM) to the Ethernet passive optical network (EPON) downstream link and compare its performance with non-frame burst mode for various traffic patterns. Although in light traffic loads (p<0.5) the efficiency of the FBM mechanism is not significant, it does feature high throughput, small jitter, low queue occupancy, and short queuing delay in optical line terminals under various traffic loads with various numbers of optical network units (ONUs). The FBM performance always approaches that of full-duplex mode, especially under heavy traffic loads (p>0.5). Moreover, an increase in number of ONUs will decrease the burst performance. Our work shows that FBM scheme is very useful for EPON transmission and has low design complexity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1323-1326
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• 2004

A bogie frame of welded type have some problems. Some end beam has cracked. The cracks have profound influence on the safe freight service. The bogie consists of a frame, suspensions, brakes and wheel sets. Various analyses including a numerical simulation using a finite element method, a static load test, a fatigue test, and running test should be carried out to design the bogie. However cracks have been found at some end beams of the bogies mounted on the freight cars running with the high speed. The cracks of the end beam results in deterioration of the brake performance and the running safety. Numerical simulations and dynamic tests are carried out to figure out the causes of cracks in the existing bogie, and the vibrational characteristics of the improved bogie are compared with those of the conventional one. In this reports, the vibration characteristics were dealed with the most pressing matters for the solution of the end beam crack.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권2호
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• pp.107-115
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• 2006

In this paper, a new speed sensorless control based on an instantaneous reactive power is proposed for the interior permanent magnet synchronous motor(IPMSM) drives. In proposed algorithm, the current observer estimates the line currents and the estimated speed can be yielded from the voltage equation because the information of speed is included in back EMF. To implement speed sensorless control, the current observer is composed by using the voltage equation of the IPMSM in the stationary reference frame fixed to the stator. The estimated speed of the rotor is composed by using the voltage equation of the IPMSM in the rotating reference frame fixed to the rotor The estimated speeds to minimize the speed error compensated by using the instantaneous reactive power. The instantaneous reactive power is calculated on the rotating reference frame fixed to the rotor. The effectiveness of the preposed algorithm is confirmed by the experiments.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.659-662
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• 2005

This paper presents a new technology, Advanced Dynamic Capacitance Compensation (A-DCC), for improved dynamic performance of LCD monitors. Conventional LCD monitors suffer from certain specific artifacts, such as wire-frame flicker and line dimming, which are not an issue for the simpler motion images found in television content. A-DCC addresses these more challenging monitor cases through an advanced architecture which analyzes multi-frame data and applies more comprehensive lookup table corrections according to the specific frame sequence.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.327-334
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• 2001

This paper presents a non-linear analysis procedure for plane frame structures by finite element formulation with assumptions of Timoshenko beam theory. Finite element displacement method based on Lagrangian formulation is used and two-noded and isoparametric line element is adopted to represent finite element model. The layered approach is used for the elasto-plastic analysis of the plane frame structures with rectangular and I cross sections. A load incremental method combined with the tangent stiffness and the initial stiffness methods for each load increment is used for the solution of non-linear equations. Numerical examples are presented to investigate the behavior and the accuracy of the elasto-plastic non-linear application and the results of this study are compared with other solutions using the concept of plastic hinge.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.50-57
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• 1995

Cylindrical space frame which have a mechanic property, a functional property, a aesthetic prioerty and so on, occupies one part of sin structures and after this, the using parts will be extended. But because this structure is made of network by combination of line elements there are many nodes the structural the structural behavior is very complicated and there can be a overall collapse of structure by buckling phenomenon if the external force reaches a limitation. In design for this structure, we must determinate layer by considering above mentioned property first of all. Therefore this study aimed at the comparison and the investigation of mechanical characteristics of single-layer and double-layer cylindrical space frame on views of behavior and buckling by use of rise ratio.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 가을 학술발표논문집 Vol.27 No.2 (2)
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• pp.407-409
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• 2000

본 논문에서는 Web 기반의 원격 교육 환경에서 강사와 학습자 모두에게 도움을 줄 수 있는 판서장면 MPEG Stream Data에서의 온라인 문자 인식 방법에 대하여 연구하였다. 강사가 별도의 프리젠테이션 자료를 만들 필요 없이 직접 판서한 MPEG Stream Data로부터 초당 3 Frame을 Sampling 한 후, 각 Frame에 Laplacian 마스크를 이용한 윤곽선 검출, Frame간 빼기 그리고 세선화 등의 영상처리 기법을 적용하여 문자인식에 필요한 좌표 값과 방향코드 등의 특징을 추출하였다. 좌표 값은 세선화 된 획의 중간 Pixel의 좌표 값이며, 구해진 좌표 값들을 이용하여 8방향 코드와 가상 획 코드를 구한 다음, 이 특징들을 사용해 은닉 마르코프 모델(Hidden Markov Model)을 학습시키고 한글 문자 인식을 행하였다.

• 한국공간구조학회논문집
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• 제21권2호
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• pp.57-66
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• 2021

This study develops finite element models for seismically-deficient reinforced concrete building frame retrofitted using fiber-reinforced polymer jacketing system and validates the finite element models with full-scale dynamic test for as-built and retrofitted conditions. The bond-slip effects measured from a past experimental study were modeled using one-dimensional slide line model, and the bond-slip models were implemented to the finite element models. The finite element model can predict story displacement and inter-story drift ratio with slight simulation variation compared to the measured responses from the full-scale dynamic tests.