• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.62-69
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• 1996

Interpolator is a very important element in NC machines in that it controls tool path and speed. In this paper, studied were extensive interpolation characteristics of reference pulse method among various interpolation and pulse generation methods. Specifically, processing speed and path error of DDA, SPD and SFG methods were compared and analyzed against line, circle and elipse. As a result, in the point of processing speed, SPD method was found to be the best for line interpolation, SFG method for circle and ellipse, and DDA method was found to be the slowest for all paths. In the point of path error, DDA method was found to have the biggest error for all kinds of paths.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.2
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• pp.119-131
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• 2024

Pulse-like ground motion can cause greater damage to structures than nonpulse-like ground motion. Currently, much research is being conducted to determine the presence or absence of velocity pulses and to quantify them from seismic-acceleration records. Existing ground motion is divided into far-field (FF) and near-fault ground motion, based on the distance of the measurement point from the fault. Near-fault ground motion is further classified into near-fault pulse-like (NFP) and near-fault nonpulse-like (NFNP) ground motion by quantifying the presence or absence of velocity pulses. For each ground motion group, 40 FF, 40 NFP, and 40 NFNP ground motions are selected; thus, 120 ground motions are used in the seismic analysis to assess the seismic fragility of sample bridges. Probabilistic seismic demand models (PSDMs) are created by evaluating the seismic responses of two types of sample bridges with lead-rubber and elastomeric rubber bearings using three groups of ground motions. Seismic fragility analysis is performed using the PSDM, and from these results, the effect of the presence or absence of seismic velocity pulses on the seismic fragility is evaluated. From the comparison results of the seismic fragility curve, the seismic fragility of NFP ground motion appears to be approximately three to five times greater than that of NFNP ground motion, according to the presence or absence of a velocity pulse of seismic waves. This means that the damage to the bridge is greater in the case of NFP ground motion than that in the case of NFNP ground motion.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.194-197
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• 2005

Pulse-mode performance evaluation is made for a set of monopropellant hydrazine thrusters producing $0.95 lb_{f}$ of nominal steady-state thrust at an inlet pressure of 350 psia. With a brief description on the hot-firing test matrix, a typical data obtained from pulse-mode firing is given directly showing the variational behavior of propellant supply pressure, vacuum condition, and thrust, in addition to the thermal response of the thruster. The performance features are successfully compared to the reference criteria of 1-lbf standard monopropellant rocket engine.

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.59-66
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• 1986

A prototype ultrasound sector B-scanner has been developed where the front-end hardware refers to all the necessary circuits for transmitting the ultrasound pulses into the human body and receiving the reflected echo signals from it. The front-end hardware can generally be divided into three parts, i.e., a pulse generator for insonification, a receiver which is responsible for processing of low-level analog signals, and a steering controller for driving the mechanical sector probe whose functions and design concepts are described in this paper. The front-end hardware is implemented which incorporates the following features: improvement of the axial resolution using a circuit which reduces the ring-down time, flexibility of generating time-gain compensation curve, and adoption of a one-chip microcomputer for generating the rate pulses based on the sensor output waveforms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1693-1698
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• 2015

This paper proposed a PFM(pulse-frequency modulator) boost converter which has dual pulse-width. The PFM boost converter is composed of BGR(band gap voltage reference generating circuit), voltage reference generating circuit, soft-start circuit, error amplifier, high-speed comparator, inductor current sensing circuit and pulse-width generator. Converter has different inductor peak current so it has wider load current range and smaller output voltage ripple. Proposed PFM boost converter generates 18V output voltage with input voltage of 3.7V and it has load current range of 0.1~300mA. Simulation results show 0.43% output voltage ripple at ligh load mode and 0.79% output voltage ripple at heavy load mode. Converter has efficiency 85% at light lode mode and it has maximum 86.4% at 20mA load current.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.77-80
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• 2005

본 논문에서는 ATSC 지상파 디지털 TV 방송방식을 사용하는 등화형 동일채널 중계기(Equalization Digital On-Channel Repeater: EDOCR)에서의 신호처리 시간지연을 최소화하기 위한 전치등화 방법에 대하여 기술하고 결과를 다양한 각도에서 분석한다. 제안된 전치등화 방법은 기준신호인 기저대역 신호와 복조된 중계기 출력신호를 이용하여 전치등화필터계수를 계산하고 펄스성형필터계수와의 컨볼루션을 통해 얻어진 새로운 펄스성형필터를 이용하는 것이다. 새로운 펄스성형필터의 전치 탭 수를 조절함으로써 시간지연을 최소화하고, 마스크필터에 의한 선형왜곡을 보상할 뿐 아니라, 원래 펄스성형필터의 대역 외 방사 특성의 열화를 최소화할 수 있다. 이를 컴퓨터 시뮬레이션 및 제작된 전치등화기를 이용하여 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.71-78
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• 2009

An 8${\times}$8-Gb/s/channel 4-PAM transceiver was designed for high speed memory applications by using 70nm DRAM process with 1.35V supply. An asymmetric 4-PAM signaling scheme is proposed to increase the voltage and time margin of upper and lower eyes in 3-class eye opening. A mathematical basis shows that this scheme statistically reduces 33% of reference noise effect in a receiver. Also, an adaptive pre-emphasis scheme, which utilizes a lone-bit pulse with integrator at the receiver, is introduced to reduce ISI for a simple DRAM channel. In this scheme, an integrating clock timing calibration by using a pre-determined pattern is proposed for the optimum ISI measurement.

• Journal of the Korea Computer Industry Society
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• v.7 no.5
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• pp.563-572
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• 2006

Advantage that light transmission treatment way of most suitable through skin can investigate light directly in part ar there is difference in ability photoelectricity month by diverse complexion of horn character department which is branch or head of a family outside part of skin and treatment according to various patient can be inappropriate. By result that this research uses color information after search each color ingredient that ingredient of HIS and YIQ that use method, color information to use skin impedance way and color information through skin area ion and difference video to do fixed measuring by light investigation way by skin impedance corresponds to skin color in an experiment though is most universal result according to patient's skin model area detection each single person's skin model through videotex automatically create and because measuring, investigate skin color, energy, wave length, approximately, transmission time, model of most suitable that draw pulse delay and so on and want and special quality, and saved standard of disease treatment pulse modeling by skin impedance, and design and manufacture light investigation pulse modeling system of most suitable by skin subordinate, and constructed suitable treatment pulse database by skin color.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.68-74
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• 2014

During the life firing test of 1 N-class thruster development model, pulse mode performance and performance changes were examined. The deviation of pulse mode response time according to thruster feed pressure was relatively small and the resultant ignition delay, response time, tail-off time were 32-35 ms, 86-91 ms, 89-98 ms, respectively. For the stabilized pulse region the impulse bit revealed the outstanding reproducibility of 1.41, 1.32, 2.10% at $3{\sigma}$. During the life firing test, the impulse bit was decreased with limited amounts, therefore the pulse mode performance could be considered to be maintained. The thrust centroid was also maintained during the life firing test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.258-264
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• 1998

본문에서 주파수hopping과 이동통신에서 요구되는 고속 주파수 전환이 가능한 새로운 주파수 신시사이저 (Synthesizer)를 제안한다. 종래의 PLL 주파수 신시사이저는 기준 주파수와 출력의 채널 주파수 간격이 동일하기 때문에 기준 주파수를 낮게 하면 매우 긴 동기 시간이 소요된다. 본 논문에서 제안하는 주파수 신시사이저는 새로운 제어 방법을 이용한 다단 펄스 제거 회로를 사용하여 기준 주파수와 채널 간격 주파수를 독립적으로 설정할 수 있기 때문에 종래의 신시사이저와 동일한 채널 간격의 주파수를 유지시키면서 기준 주파수를 높일 수 있고, 또한 루프(loop)이득을 크게 할 수 있다. 따라서 종래의 주파수 신시사이저보다 주파수 절환시간을 크게 단축할 수 있다. 본 논문에서는 주파수 절환시간을 1/100 정도 단축시킬 수 있음을 보여주고 있다.