• Title/Summary/Keyword: single-pass

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Korean Character Recognition Using Optical Associative Memory (광 연상 기억 장치를 이용한 한글 문자 인식)

  • 김정우;배장근;도양회
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.6
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    • pp.61-69
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    • 1994
  • For distortion-invariant recognition of Korean characters, a holographic implementation of an optical associative memory system is proposed. The structure of the proposed system is a single-layer neural network employing interconneclion matrix, thresholding and feedback. To provide the interconnection matrix, we use two CGII's which are placed on intermcdiate plane of cascaded Vander Lugt corrclators to form an optical memory loop. The holographic correlator stores reference images in a hologram and retrives them in a coherently illuminated feedback loop. An input image which maybe noisy or incomplete, is applicd to the system and simultaneously correlated optically with all of the stord images. These correlations are throsholed and fed back to the input, where the strongest correlation reinforces the input image. The enhanced image passes arround the loop repeatedly, approaching the stored image more closely on each pass until the system stabilizes on the desired image. The computer simulation results show that the proposed Korean Character recognition algorithm has high discrimination capability and noise immunity.

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1-Gb/s Readout Amplifier Array for Panoramic Scan LADAR Systems (파노라믹 스캔 라이다용 1-Gb/s 리드아웃 증폭기 어레이)

  • Kim, Dayeong;Park, Sung Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.3
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    • pp.452-456
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    • 2016
  • In this paper, a dual-channel readout amplifier array is realized in a standard $0.18{\mu}m$ CMOS technology for the applications of panoramic scan LADAR systems. Each channel consists of a PIN photodiode with 0.9 A/W responsivity and a 1.0 Gb/s readout amplifier(ROA). The proposed ROA shares the basic configuration of the previously reported feedforward TIA, except that it exploits a replica input to exclude a low pass filter(LPF), thus reducing chip area and improving integration level, and to efficiently reject common-mode noises. Measured results demonstrate that each channel achieves $70dB{\Omega}$ transimpedance gain, 829 MHz bandwidth, -22 dBm sensitivity for $10^{-9}BER$, -34 dB crosstalk between adjacent channels, and 45 mW power dissipation from a single 1.8 V supply.

A Novel Method for Bitrate Control within Macroblocks Using Kalman and FIR Filters

  • Seok, Jin-Wuk;Yoon, Ki-Song;Kim, Bum-Ho;Lee, Jeong-Woo
    • ETRI Journal
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    • v.33 no.4
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    • pp.641-644
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    • 2011
  • In this letter, we propose a novel bitrate control, using both Kalman and FIR filters, based on a Hamiltonian analysis with respect to the amount of bits from each macroblock, in an encoding of a general video codec such as H.264/AVC. Since the proposed bitrate control is based on the simple computation of an optimal control method based on the Hamiltonian analysis, it is not necessary to use additional computation, such as a DCT or quantization, to estimate the bits for bitrate control. As a result, the proposed algorithm can be applied to single-pass encoding and can provide sufficient encoding speed with respect to various applications, even those requiring real-time control.

An experimental study on the flow characteristics of a supersonic turbine cascade (초음속 터빈 익렬의 유동특성에 대한 실험적 연구)

  • Cho, Jong-Jae;Jeong, Soo-In;Kim, Kui-Soon;Park, Chang-Kyu
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1732-1737
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    • 2004
  • In this paper, a small supersonic wind tunnel is designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The flow is visualized by means of a single pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of nozzle installation angle. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions are observed.

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NEW MODELING AND CONTROL OF AN ASYMMETRIC HYDRAULIC ACTIVE SUSPENSION SYSTEM

  • Kim, Wanil;Sangchul Won
    • 제어로봇시스템학회:학술대회논문집
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    • 1998.10a
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    • pp.490-495
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    • 1998
  • In this paper an asymmetric hydraulic actuator which consists of single acting cylinder and servo valve is modeled for a quarter car active suspension system. This model regards the force as an internal state rather than a control input. The control input of the model is the sum of oil flows that pass through the valve's orifices. The resulting dynamic equation in the state space ap-pears a feedback connection of a nominal linear time in-variant term with a nonlinear bounded uncertain block. Since this model makes it possible to eliminate the force control phase, analysis and controller design are made straightforward and simple. Well known LQR method is then applied. Simulation and test rig experiment show the effectiveness of this approach in modeling and control.

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Halftoning Method by CMY Printing Using BNM

  • Kim, Yun-Tae;Kim, Jeong-Yeop;Kim, Hee-Soo;Yeong Ho ha
    • Proceedings of the IEEK Conference
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    • 2000.07b
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    • pp.851-854
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    • 2000
  • Digital halftoning is a technique to make an equivalent binary image from scanned photo or graphic images. Low pass filtering characteristic of human visual system can be applied to get the effect of spatial averaging of local area consisted of black and white pixels for gray image. The overlapping of black dot decreases brightness and black dot is very sensitive to human visual system in the bright region. In this paper, for gray-level expression, only bright gray region in the color image is considered for blue noise mask (BNM) approach. To solve this problem, BNM with CMY dot is used for the bright region instead of black dot. Dot-on-dot model with single mask causes the problem making much black dot overlap, color distortion. Therefore approach with three masks for C, M and Y each is proposed to decrease pixel overlap and color distortion.

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An experimental study on the flow characteristics of a supersonic turbine cascade

  • Cho, Jong-jae;Jeong, Soo-in;Kim, Kui-soon;Lee, Eun-seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.03a
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    • pp.807-812
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    • 2004
  • In this paper, a small supersonic wind tunnel was designed and built to study the flow characteristics of a supersonic impulse turbine cascade by experiment. The flow was visualized by means of a single pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of pressure ratio. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions were observed.

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A Study on the Performance Analysis of Mobile Fuel Cell (모바일용 연료전지의 성능해석에 관한 연구)

  • Kim, Kwang-Soo;Choi, Jong-Pil;Jeong, Chang-Ryeol;Jang, Jae-Hyeok;Jeon, Byeong-Hee;Kim, Byeong-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.1
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    • pp.115-121
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    • 2008
  • In this paper, a three-dimensional computational fluid dynamic model of a proton exchange membrane fuel cell(PEMFC) with serpentine flow channel is presented. A steady state, single phase and isothermal numerical model has been established to investigate the influence of the GDL (Gas Diffusion Layer) parameters. The GDL is made of a porous material such as carbon cloth, carbon paper or metal wire mesh. For the simplicity, the GDL is modeled as a block of material having numerous pathways through which gaseous reactants and liquid water can pass. The porosity, permeability and thickness of the GDL, which are employed in the model parameters significantly affect the PEMFC performance at the high current region.

Simultaneous measurement of oxygen permeability by using of multi-functional oxygen electrode (다기능 산소전극에 의한 산소투과특성 동시측정)

  • 이동희;정진휘;유형풍;김태진
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.532-535
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    • 2000
  • We have fabricated a sensor system for on-line monitoring the oxygen permeability and diffusivity of six different polymer films using the miniaturized 6 cathode(Ag)-single anode(Ag/AgCl) type hexagonal oxygen electrode. This system consists of multiple input front-end electronics, signal conditioning circuit using the embedded microcontroller 80C196KC, PC interface circuit and PC with the OS for microcontroller and the operating program for this system. The digital low-[ass filter was programmed and the simulated filter characteristics were enough to eliminate the noise from sensor signal. According to the experimental results, the linearity coefficients of the output voltage to oxygen partial pressure for each sensor electrode of six cathode type oxygen sensor are 0.998, 0.997, 0.998, 0.997, 0.997, 0.997 respectively, and the response times are all within 4 minutes.

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Selection of Adaptive GOP Structure based Complexity (복잡도를 기반한 적응적 GOP 구조 선택)

  • Choi, Kum-Su;Chung, Hee-Tae;Moon, Young-Oeuk
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.2675-2677
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    • 2001
  • MPEG에서 GOP의 길이가 고정되어 있다 하더라도 부호화 효율 측면에서 최상의 화질을 제공하지는 않는다. GOP의 길이 N은 약 0.5초의 랜덤 접근을 위해 15나 12로 고정되고 있으며 P-picture의 구간 M은 GOP 구조를 정의하는 중요한 변수중의 하나이다. 이것은 원 영상의 특성과는 관계없는 부호화 수행으로 M=3은 영상 시퀸스에 널리 사용되고 있다. 그러나 P-picture의 구간 M=3은 모든 영상열에 좋은 화질을 제공하는 것은 아니다. 우리는 실시간 MPEG-2 비디오코딩을 위한 적응적 GOP구조 선택 방법을 제안한다. 이 방법은 single-pass 부호화를 갖는 코딩 복잡도를 기반으로 하여 3개의 picture 구간에서 P-picture의 구간 M을 동적으로 적응시킨다.

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