• 한국지능시스템학회논문지
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• 제22권4호
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• pp.476-480
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• 2012

본 논문에서는 선도 로봇을 추종하는 군집 로봇의 대형 제어를 인공 포텐셜 장을 사용하여 제안한다. 또한, 인공 포텐셜 장은 물리적으로 해석하기 쉬운 전기장을 모델링하여 구성하고, 장애물을 더욱 효과적으로 모델링하기 위해서, 장애물의 모양에 따라 전기장의식을 달리한다. 제안하는 방법은 선도 로봇의 경로를 인공 포텐셜 장을 통해 계획한 뒤, 선도 로봇을 추종 로봇이 뒤따라가는 형태로 구성된다. 마지막으로 시뮬레이션 예제를 통해 제안하는 기법의 타당성을 검증한다.

• 한국항해학회지
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• 제22권3호
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• pp.27-34
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• 1998

The paper is the second part on the 3-D sound-field creation implementing the Virtual Reality Ship Handling Simyulator(VRSHS). As mentioned in the previous part Ⅰ, the spatial impression, which arose from reproduced 3-D sound-field , give natural sound environmental context to a listener. This spatial impression is due to the reverberation by reflections and ,is can be obtain by using Head-Related Transfer Function(HRTF). In this work, we foumulate early and late reverberation models of the HRTF's with theoretical control factors based on the sound-energy distribution in an irregularly shaped enclosures. Using the reverberation models, we report results from psychophysical tests used to asses the validity of the proposed 3-D soud-field control method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.696-698
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• 2004

In this paper we design $H_{\infty}$ infinity controller for Induction motor with low speed operation. $H_{\infty}$ controller is applied in order to design a state feedback static controller for field oriented control of an induction motor. $H_{\infty}$ controller are linear plant can be set up using the same assumptions that are at the basis of field oriented control. Thus, $H_{\infty}$ control theory can be successfully used to set up a state feedback controller for field oriented control of an induction motor. The performances of the $H_{\infty}$ controller is numerically analysed and experimentally verified to prove the validity of the design procedure. In this paper show that performances with high robustness to variations of system parameter.

• The Korean Journal of Ecology
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• 제13권1호
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• pp.1-8
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• 1990

Effects of mycorrhizal infection on the growth of bell pepper (Capsicum annuum) and corn (Zea mays) seedlings have been studied by comparing plants grown in sterilized soil/sand mixtures to plants grown in sterilized soil/sand mixtures with topping the original non-sterile field soil. The original nonsterile field soil, which were taken from the bell pepper field, contained a high level of endmycorrhizal spores. After seven weeks, the shoot height of inoculated plants was increased by 110% in bell pepper, and 90% in corn compared with the control plants. The average above-ground biomass of inoculated plant was increased by 88% in bell pepper and 71% in corn compared with the control plants. The shoot-root ratios in bell pepper and corn were 2.7 and 1.8 for the control plants, and 4.3 and 2.7 for the treatment plants, respectively. Phosphorus level in inoculated plant was higher than that of the control plant. However, nitrogen contents were similar between the control and the treatment plants. The control plants didi not form vesicular-arbuscular mycorrhizae during the experimental period.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1169-1171
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• 2001

Synchronous reluctance motors(SynRM) for the application such as an electric vehicle, compressor drives of air conditioner and machine tool spindle drives require a wide field-weakening speed range. In order to improve the efficiency performance in such applications, this paper has examined the loss and the efficiency characteristics of SynRM mainly in the field-weakening speed region over the base speed. The control strategy in order to offer a efficiency optimization operation is shown and the copper and iron losses driven the equivalent circuit model of the machine is minimized. The usefulness of the proposed efficiency optimization control is verified through the SynRM durve system.

• 한국화재소방학회논문지
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• 제23권4호
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• pp.145-153
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• 2009

화재안전기준 NFSC 501A에 의하면 몇 가지 제연구역 선정방법이 있지만, 특별피난계단 부속실만을 단독으로 제연하는 경우가 보편화 되고 있다. 그러나 여기에는 상당한 문제점이 있다. 저자의 책임 감리현장도 다른 많은 유사 현장과 같이 부속실만 단독제연하는 것으로 설계되어 있다. 그 설계내용에서 몇 가지 문제점을 도출하고, 이를 해소하기 위한 대안으로 굴뚝효과를 고려한 공학적 분석방법에 의한 "계단실 및 그 부속실을 동시에 제연하는 것"으로 설계 변경하는 것이 가장 적합하다는 결론을 얻었다.

• 한국소음진동공학회논문집
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• 제16권5호
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• pp.479-484
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• 2006

This paper presents an active control of the aperture type near-field storage head. In order to achieve a fast and accurate control, a dual servo control algorithm is applied. Based on the big difference in time constants of two actuators, they are used independently. With the combination fine and coarse actuator, the disk is rotated up to 10 rpm speed until the gap is controlled within 100 nm. From the experimental results, the feasibility and the performance of active dual servo gap control is proved.

• 유공압시스템학회논문집
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• 제6권4호
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• pp.9-15
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• 2009

Hydraulic excavators are the representative of field robot and have been used in various fields of construction. Since the excavator operates in the hazardous working environment, operators of excavator are exposed in harmful environment. Therefore, the hydraulic excavator automation and remote operation system has been investigated to protect from the hazardous working environment. In this paper, remote operation excavator system is developed using the mini hydraulic excavator and the tracking control system of each links of excavator is designed. To apply the tracking control system, the adaptive sliding mode control algorithm is proposed. It is found that the performance of the proposed control system is improved through experimental results of using the remote operation excavator system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.182-185
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• 1998

This paper describes a field orientation control of an induction motor without any speed transducer and proposes a wide-range speed control strategy with the field orientation algorithm. The difference at impedances between the direct and quadrature axis at the injected signal is used for the sensorless field orientation control. But this algorithm has some limitations and should be supported by other method at high speed. In this paper, a sensorless speed control at an induction motor for wide speed range operation is proposed. The proposed algorithm is verified by experimental results.

• 한국자동차공학회논문집
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• 제4권6호
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• pp.164-174
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• 1996

This paper presents control and response characteristics of a continuously variable ER(electrorheological) damper for small-sized vehicles. The ER damper is devised and its governing equation of motion is derived from the bond graph model. The field-dependent yield shear stresses are distilled from experimental investigation on the Bingham property of the ER fluid. The distilled data are incorporated into the governing system model and, on the basis of this model, an appropriate size of the ER damper is manufactured. After evaluating the field-dependent damping performance of the proposed ER damper, the skyhook control algorithm is formulated to achieve desired level of the damping force. The controller is then experimentally implemented and control characteristics of the ER damper are presented in order to demonstrate superior controllability of the damping force. In addition, response characteristics of the damping force with respect to the electric field with fast on-off frequency are provided to show the feasibility of practical application.