• 한국멀티미디어학회논문지
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• 제21권9호
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• pp.1068-1075
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• 2018

We propose a method for driving loudspeakers from class D audio power amplifiers in current mode, instead of in conventional voltage mode, which was impossible with the feedback circuitry. Unlike analog audio amplifiers, Class D audio power amplifiers have signal delay between the input and output signals, which makes it difficult to apply the feedback circuitry for current-mode driving. The idea of the pre-distortion scheme used for the compensation of the non-linearity of RF power amplifiers is adapted to remedy the impedance variation effect of the loudspeakers for current driving. The method uses the speaker model for the pre-distorter to compensate for the speaker impedance variation with frequency. The simulation and test results confirms the validity of the proposed method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1995년도 가을 학술발표회 논문집
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• pp.41.1-44
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• 1995

The JV method is an epochal civil engineering style that boasts of significant pile driving power through low-vibration works by ideally combining the high pressure water injected from the water jet cutter and the vibrations combining from the vibratory pile driver extractors. As a result, you are ensured stable and safe pile driving and extraction in bedrocks that were previously impossible with conventional machines and methods. The other advantage is its high performance and a low-pollution characteristis that is ensured by suppressing ground vibrations. This is a very important factor since it often becomes an issue upon civil engineering in the city. With the addition of this method. the range of steel pipe pile, steel sheet pile and other steel pile use has been drastically expanded. Other advantages of this method incldes accurate works, shortening of the construction period and improved work performance. Since the minimun amount of high pressure water is used to drill the ground, it not only loosens the ground, but also cuts the ground at the tip of the pile to improve driving works.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.56-61
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• 2023

The characteristics of write discharge were investigated when the conventional driving method with the unipolar sustain voltages, and the single sustain driving method applying the bipolar sustain voltage were applied in an AC plasma display. In the case of having a single sustain waveform, the strength of the write discharge is weakened compared to the conventional driving method during the address period, because the wall charge inside the panel is more dissipated by the lower scanning voltage. In the driving method with a single sustain waveform, the bias voltage of the other electrodes was changed to improve the write discharge characteristics. As a result, the intensity of the discharge was enhanced by 32% and the delay time was shortened by 60 ㎲.

• 대한교통학회지
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• 제31권5호
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• pp.48-59
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• 2013

본 연구에서는 도로투자 사업으로 인한 편익 중 일반적으로 계상하고 있는 통행시간 절감 및 차량운행비용 절감 등 직접적인 편익 이외에 추가적으로 이용자입장에서 체감할 수 있는 도로 주행 중 운전쾌적성 편익을 산정하고자 운전쾌적성의 정의를 마련하였고 운전쾌적성 산정방법론을 개발하였다. 도로특성(도시부/지방부) 및 차량 밀도(차간거리)에 따른 이용자의 지불용의액을 CVM 방법 중 가장 최근에 활발히 활용되고 있는 이중양분선택형(double-bounded dichotomous choice)질문법을 활용하여 설문조사한 후 그 결과를 로짓모형에 적용하여 운전쾌적성 가치를 도출하였다. 도시부 및 지역간 도로에서 공히 지불용의액의 크기는 전반적으로 기존 차간거리가 짧을수록 큰 것으로 분석되었고, 도로의 차간거리 변화가 같더라도 사업 전의 차간거리와 사업 후의 차간거리에 따라 지불용의액이 다른 것으로 나타났다. 즉, 도로의 차간거리가 증가하더라도 기존 차간거리가 어느 정도인지에 따라 지불용의액이 다르게 나타나 지불용의액이 기존 차간거리에 영향을 받는 것으로 분석되었다.

• 한국군사과학기술학회지
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• 제22권5호
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• pp.674-686
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• 2019

In this paper, we will discuss the absolute angular error control mode for the Gun/Turret driving system. The Gun/Turret driving controller receives absolute angular error calculated from the fire control system (FCS). Thus, the Gun/Turret driving controller is subjected to step command to cause residual vibration and system unstable. In order to reduce residual vibration and to ensure the system stability, we propose an error motion profile method with two types of trapezoidal and S-Curve. The validity of the proposed error motion profile method is confirmed via simulation by observing that the resulting position error, driving power, and power density satisfied the control performance.

• 한국음향학회지
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• 제18권8호
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• pp.108-115
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• 1999

본 연구에서는 차 실내의 공간 음향특성으로 인한 음향왜곡과 주행소음으로 인한 오디오 음질 저하를 동시에 개선하기 위한 디지털 필터를 설계하여 음질을 개선하는 방법을 제안하였다. 라우드스피커의 입력에 적용할 디지털 필터는 차량 주행 소음 특성과 차 실내의 음향특성을 고려하여 설계하였다. 차량소음 분석은 주파수 옥타브 밴드 분석법을 이용한 객관적인 분석과 감성적 분석법인 NCB 곡선법을 사용했다. 그 결과를 이용하여 오디오 유니트의 11밴드 디지털 필터 보정치를 구하는데 사용하였다. 최적 음질 구현을 위해 7가지 형태의 디지털 필터를 설계하여 기준 음악원에 적용하여 음악원 샘플을 얻었고, 여기에 100km 차량 주행소음을 합성한 9가지의 음악원 샘플을 제작하였다. 64명의 평가자를 대상으로 Scheffe'가 제안한 7점 주관 평가법을 사용하여 9가지 음악원 샘플에서 최적음질을 나타내는 디지털 필터를 선택하였다.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.65-76
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• 2000

To measure the fuel consumption rate of a vehicle, a car is tested on chassis dynamometer following given driving mode. But the fuel consumption rate measured by this method may be somewhat different from that measured in on-road driving conditions. It may be due to not considering road grade in driving modes. In this study, new driving modes which include road grade are proposed, and the simulation program to estimate the real driving fuel consumption rate of a vehicle is developed. On-road car tests to verify the simulation program are carried out and the results of the simulation are analysed and compared with those of the experiments.

• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.233-236
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• 2012

The driving properties of a particle-insertion method that filters non-moving particles are analyzed, by measuring its optical and electrical properties. An area that is occupied by the moved particles is proposed, as a desirable evaluation method for a reflective display. To compare the driving property of the particle-moving method with that of the reported simple particle-loading method, two panels are fabricated, according to the different particle-insertion methods, in the same panel condition, of which the width of ribs is $30{\mu}m$, the cell size is $220{\mu}m{\times}220{\mu}m$, the cell gap is $116-120{\mu}m$, the q/m value of the black particles is $+1.8{\mu}C/g$ and that for the white particles is $-4.3{\mu}C/g$. The particle-moving method has a filtering effect which excludes the non-moving particles, inserting only movable particles into the respective cell, so that a panel fabricated by the particle-moving method can drive most of the particles in a cell. Also, most of the particles move at the threshold voltage of 40 V, with enhanced reflectivity. The driving property is also verified by measurement of the occupation rate of the moved particles.

• 로봇학회논문지
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• 제5권2호
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• pp.120-126
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• 2010

This paper presents to study the path tracking method of AGV(autonomous guided vehicle) which has a laser guidance system. An existing automatic guided vehicles(AGVs) which were able to drive on wired line only had a automatic guidance system. However, the automatic guidance systems that those used had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the laser guidance system which is consisted of a laser navigation and gyro, encoder. That is robust against noise, and flexible according to working environment through sensor fusion. The laser guidance system can do a perfect autonomous driving. However, the commercialization of perfect autonomous driving system is difficult, because the perfect autonomous driving system must recognize the whole environment of working space. Hence, this paper studied the path tracking of AGV using laser guidance system without wired line. The path tracking method is consisted of virtual path generation method and driving control method. To experiment, we use the fork-type AGV which is made by ourselves, and do a path tracking experiments repeatedly on same experimental environment. In result, we verified that proposed system is efficient and stable for actual fork-type AGV.

• 대한통합의학회지
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• 제5권4호
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• pp.77-81
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• 2017

Purpose : This study examined the effects of driving rehabilitation functional training on visual perception ability and driving reaction velocity. Those subjects were put under MVPT-3 test to see their visual perceptual functions before and after the 4weeks' driving rehabilitation function training and then put to TMT A-type test to see their driving reaction velocity performance. The followings are the results of this study. Methods : Using a driving simulator, driving rehabilitation functional training was performed targeting men and women aged in 20s 20 minutes per time, two times per week, for a month. Results : As for the change in visual perception, the Raw Score of MVPT-3 very significantly increased (p<.01), and the Standard Score also very significantly increased (p<.01). As for the change in reaction velocity, TMT A-type very significantly decreased (p<.01), and TMT B-type also very significantly decreased (p<.01). Conclusion : It could be found that driving rehabilitation functional training should be effective for both visual perception and reaction velocity. Consequently, the driving rehabilitation function training can be applied to clinics as training method for functional recovery and improvement of visual perceptual functions and driving reaction velocity performance ability of the patients. Thus, various functional programs should be studied in the future.