• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.168-171
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• 2003

Generally RF AGC (Roll Force Automatic Gauge Control) controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but RE AGC takes the bad effect of the roll eccentricity. The Feed-forward (FF) AGC method, which controls the next stand roll gap by the estimation of the thickness variation due to skid mark is needed to supplement the shortage of RF AGC. In this paper, an adaptive filtering method which takes account of the kind of material, the final objective thickness and the rolling speed is proposed to predict skid mark thickness variation. In addition, an improved estimation method of control point using a speedometer and looper angle is suggested. Via on line test, the performance improvement of the suggested FF AGC method is verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1798-1799
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• 2011

In this paper, A new cost-effective and accurate input noise rejection method for High Speed Counter module of PLC (Programmable Logic Controller) is proposed. By using combination of simple additional logic circuit and the Timer Pulse function of general purpose MPU, Cost-effectiveness and improvement of accuracy of filtering function can be achieved. This proposed method is verified by simulation. This proposed method is much useful for simple industrial controller based on simple microprocessor because of simplicity, accuracy and low cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1104-1107
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• 1992

Voltage controlled current regulated PWM(pulse width modulation) of VSI (voltage source inverter) is proposed. Adopting one degree of freedom, the voltage, the current controller shows much more improvement than conventional ones not using this method. The voltage controller or this proposal needs load's parameters, torque value, rotational speed. This voltage controller is located at converter part which links AC source and DC bus. With this proposed method, duty ratio of the inverter's switching is nearly unity for all speed and torque range. Hence, this method gets many advantages such as reducing current ripple, thermal loss, and noises and improving control performances. Theoretical approach to this voltage-current controller is performed, and the results are presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.40-40
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• 2000

Generally a RF AGC controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but these can not be classified. The Feed- forward AGC method, which controls the next stand roll 9ap by estimation the skid mark of the previous stand output thickness is needed to supplement the shortage of RF AGC. In this paper, an improved filtering method of skid mark which take account of the kinds of materials, the final objective thickness and the roll speed is proposed, In addition, an improved estimation method of control point using the speedometer and looper angle is suggested, Via simulation, the performance improvement of the suggested FF AGC method is verified.

• Journal of electromagnetic engineering and science
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• 제4권1호
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• pp.23-29
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• 2004

In this paper we analyze convergence constraints and time constant of IT-LMS algorithm and derive a method of making it's time constant independent of signal power by using input variance estimation. The method for estimating the input variance is to use a single-pole low-pass filter(LPF) with common smoothing parameter value, θ. The estimator is with narrow bandwidth for large θ but with wide bandwidth for small θ. This small θ gives long term average estimation(low frequency) of the fluctuating input variance well as short term variations (high frequency) of the input power. In our simulations of multipath communication channel equalization environments, the method with large θ has shown not as much improved convergence speed as the speed of the original IT-LMS algorithm. The proposed method with small θ=0.01 reach its minimum MSE in 100 samples whereas the IT-LMS converges in 200 samples. This shows the proposed, tap-power normalized IT-LMS algorithm can be applied more effectively to digital wireless communication systems.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.679-688
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• 2007

We select the 'rapid reading and comprehension method' to promote the reading skill, and want to apply it to students to study how their reading speed and comprehension improves. For this purpose, in this paper, we define reading as an accurate and quick ability to process information, and the object of this research is to verify a scheme to improve the reading skill, which is called the 'rapid reading and comprehension method - reading based on this method means fast reading as well as an accurate understanding which increases the amount of information received'. For data collection, we selected four primary school in the Kimje city. We found out validation the effective improvement of the reading ability by the 'rapid reading and comprehension method program'. The students' reading speed was enhanced by the rapid reading training and the comprehension ability increased as well.

• 한국정보통신학회논문지
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• 제6권4호
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• pp.582-588
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• 2002

본 연구에서는 브러시리스 직류 전동기(BLDCM)에 대한 효율적인 센서리스 운전 기법을 제시한다. 제시된 기법은 인버터 스위칭 주파수(4KHz, 6KHz, 8KHz)를 회전속도에 따라 적절히 가변함으로서 넓은 속도 범위에서 운전성능과 효율을 향상시킬 수 있다. 실험결과들은 제시된 기법이 제형파 역기전력을 갖는 BLDCM의 센서리스 운전특성을 효율 적으로 개선 할 수 있음을 보여주고 있다.

• 한국환경과학회지
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• 제14권1호
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• pp.15-22
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• 2005

Natural gas possesses several characteristics that make it desirable as an engine fuel; 1)lower production cost, 2)abundant commodity and 3)cleaner energy source than gasoline. Due to the physics characteristics of natural gas, the volumetric efficiency and flame speed of a natural gas engine are lower than those of a gasoline engine, which results in a power loss of $10-20{\%}$ when compared to a normal gasoline engine. This paper describes the results of a research to improve the performance of a natural gas engine through the modification and controls of compression ratio, air/fuel ratio, spark advance and supercharging and method of measuring flame propagation velocity. It emphasizes how to improve the power characteristics of a natural gas engine. Combustion characteristics are also studied using an ion probe. The ion probe is applied to measure flame speed of gasoline and methane fuels to confirm the performance improvement of natural gas engine combustion characteristics.

• Journal of electromagnetic engineering and science
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• 제13권3호
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• pp.151-157
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• 2013

Marine radars are affected by sea and rain clutters, which can make target discrimination difficult. The clutter standard deviation and improvement factor are applied using multiple parameters-moving speed of radar, antenna speed, angle, etc. When a radar signal is processed, a Data Matrix Bank (DMB) filter can be applied to remove sea clutters. This filter allows detection of a target, and since it is not affected by changes in adjacent clutters resulting from a multi- target signal, sea state clutters can be removed. In this paper, we study the level for clutter removal and the method for target detection. In addition, we design a signal processing algorithm for marine radars, analyze the performance of the DMB filter algorithm, and provide a DMB filter algorithm design. We also perform a DMB filter algorithm analysis and simulation, and then apply this to the DMB filter and cell-average constant false alarm rate design to show comparative results.

• Korean Journal of Acupuncture
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• 제24권3호
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• pp.47-54
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• 2007

A Case Report of Communication disorder associated with Post-stroke Objectives : The Objective Is the Report of Improvement in Communication Disorder Associated with Post-Stroke. Methods : Acupuncture And Medicinal Treatments Were Performed from 17th March 2006 until 8th April 2006. The Medicines Bangpungtongsung-san and Chungpesagan-tang Were Used to Improve Patient Bowel Movement. The Sa-Am Acupuncture Method Was Used to Improve Patient Communication Disorders. Every 5 Days Articulation Accuracy, Vowel Accuracy, Alternation and Speed of Reading Sentences Were Evaluated. Results : After 23 Days of Treatment There was Improvement of Articulation Accuracy, Alternation and Speed of Reading Sentences.