• 제목/요약/키워드: Control thresholds

검색결과 163건 처리시간 0.029초

바퀴/4 족 동작 전환으로 계단 및 문턱 오르기가 가능한 서비스 하이브리드 이동 로봇 개발 (Development of a Service Hybrid Mobile Robot for Climbing Stairs and Thresholds by Switching Wheel and Leg Gait)

  • 김진백;김병국
    • 제어로봇시스템학회논문지
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    • 제13권11호
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    • pp.1082-1091
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    • 2007
  • In this paper, we developed a new hybrid mobile robot which can climb stairs and go over thresholds by crawl gait with embedded real-time control software. This robot is also categorized into hybrid robot that has advantages of wheeled mobile robot and legged mobile robot, but adopts gait feature of crocodile named belly crawl. We imitated the belly crawl using four legs of 2 DOF, four omni-directional wheels, and embedded control software which controls legs and wheels. This software is developed using RTAI/Linux, real-time drivers. As a result, the new hybrid mobile robot has crawl gait. Using this feature, the new hybrid mobile robot can climb stairs and go over thresholds just by path planning of each leg with size of stairs and thresholds, and computing the movement distance of robot body center without considering stability. The performance of our new hybrid mobile robot is verified via experiments.

FDDI 네트워크의 파라미터 튜닝에 의한 과부하 제어 메카니즘 (Overload control mechanism by parameter tuning in FDDI networks)

  • 이준호;김경신;강문식;송명렬;이상배
    • 전자공학회논문지A
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    • 제32A권4호
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    • pp.32-39
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    • 1995
  • In this paper, a timer thresholds tuning algorithm is proposed, satisfying the required response time for traffic with time-critical applications and asynchronous traffic in FDDI network. Under light and medium load, priorities and timer thresholds play a minor role for medium access control. In these cases all quenes are served exhaustively with a ver high service probability and the packet loss probability approaches almost zero. Under overload condition, however, the performance of the FDDI Network is completely determined by the selection of the timer thresholds. The timer thresholds tuned by mathematical results is confirmed by simulation results using SIMAN/UNIX package. The allocation of guaranteed bandwidth can be controlled easily by tuning the timer thresholds according to the proposed rules.

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두부전방자세에 의한 불수의적 근수축이 두개주위근의 압력 통증 역치에 미치는 영향 (The effect of involuntary muscle contraction due to forward head position in pressure pain threshold of pericranial muscle)

  • 채윤원;김진상
    • The Journal of Korean Physical Therapy
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    • 제12권3호
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    • pp.339-347
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    • 2000
  • To elucidate pressure pain threshold of pericranial muscle due to involuntary. the effect of 30 min or forward head position(FHP) was studied in 20 patients with episodic tension-type headache and in 20 control without headache. Pressure pain thresholds were recorded before and after the FHP. and evaluated by pressure algometry. Thresholds increased in the patients and control after FHP. Relation between thresholds in patients anf control before FHP were not significant differences, but thresholds increased in patients after FHP. So, involutary muscle contraction due to FHP may be effect pressure pain threshold or pericranial muscle.

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Tuning the Parameters for the Decision Making System in Order to Define Athlete's Aerobic and Anaerobic Thresholds

  • Ketola, Jaakko;Saastamoinen, Kalle;Turunen, Esko
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.317-320
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    • 2004
  • In this work we have managed to find parameters for defining athlete's aerobic and anaerobic thresholds. Thresholds which are of vital importance for top athletes. It is shown how differential evolution and different similarity measures has been used to tune computational model for threshold definitions. From our results it is obvious that the use of right parameter values for this kind expert system is of vital importance.

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중주파 전류의 주파수가 감각 역치에 미치는 영향 (The Influence of Medium Frequency Currents According to Frequency on Sensory Threshold)

  • 유진호;황태연;정진규
    • 대한임상전기생리학회지
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    • 제7권1호
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    • pp.23-27
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    • 2009
  • Purpose : The purpose of this study was to examine the effects of different medium frequency currents on afferent fibers. Methods : Thirty healthy volunteers who had no known history of neurological disorders were equally assigned to one of three groups; 2500Hz, 4000Hz, and control and each group was applied to the left wrist in palmer cutaneous branch of radial nerve by different medium frequency currents for 15 min. We measured the changes of thresholds for tactile, two-point discrimination, and thresholds for pain. Results : The results showed that the medium frequency currents stimulation increased thresholds for tactile, two-point discrimination, and thresholds for pain. However, there is no statistically significant difference between group 2500Hz and group 4000Hz. Conclusion : This may explain thresholds for tactile, two-point discrimination, and thresholds for pain plain medium frequency currents stimulation inhibits the excitability of afferent fibers, but the effect of the frequency difference within medium frequency currents is not demonstrated.

적외선 영상 표적추적 성능 개선을 위한 적응적인 자동문턱치 산출 기법 연구 (Adaptive Automatic Thresholding in Infrared Image Target Tracking)

  • 김태한;송택렬
    • 제어로봇시스템학회논문지
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    • 제17권6호
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    • pp.579-586
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    • 2011
  • It is very critical for image processing of IIR (Imaging Infrared) seekers to achieve improved guidance performance for missile systems to determine appropriate thresholds in various environments. In this paper, we propose automatic threshold determination methods for proper thresholds to extract definite target signals in an EOCM (Electro-Optical Countermeasures) environment with low SNR (Signal-to-Noise Ratios). In particular, thresholds are found to be too low to extract target signals if one uses the Otsu method so that we suggest a Shifted Otsu method to solve this problem. Also we improve extracting target signal by changing Shifted Otsu thresholds according to the TBR (Target to Background Ratio). The suggested method is tested for real IIR images and the results are compared with the Otsu method. The HPDAF (Highest Probabilistic Data Association Filter) which selects the target originated measurements by taking into account of both signal intensity and statistical distance information is applied in this study.

고추 세균점무늬병 발생에 따른 수량 변화와 경제적 방제수준 설정 (Determination of Economic Control Thresholds for Bacterial Spot on Red Pepper Caused by Xanthomonas campestris pv. vesicatoria)

  • 김주희;정성수;이기권;임주락;이왕휴
    • 식물병연구
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    • 제21권2호
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    • pp.89-93
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    • 2015
  • 고추 세균점무늬병이 수량에 미치는 영향을 조사하여 경제적 방제수준을 설정하고자 시험을 수행하였다. 노지고추 세균점무늬병 발생정도와 수량과의 회귀식은 Y=-0.724X+281.58, $R^2=0.78$, $r=-0.88^{**}$ 성립하였다. 노지고추 세균점무늬병 발생정도와 수량감소와의 회귀식은 Y=0.813X+15.95, $R^2=0.78$, $r=0.88^{**}$ 성립하였다. 성립된 회귀식을 이용하여 노지 고추 수량에 영향을 주지 않는 수준의 세균점무늬병 방제적기는 발생 발병엽률이 30.3% 이하이었다. 또한 고추 세균점무늬병 경제적 방제수준은 노지 고추 세균점무늬병 발생정도가 16.3% 이하로 결정되었다.

Number Plate Detection System by Using the Night Images

  • Yoshimori, S.;Mitsukura, Y.;Fukumi, M.;Akamatsu, N.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.1249-1253
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    • 2003
  • License plate recognition is very important in an automobile society. This is because, since plate detection accuracy has large influence on subsequent number recognition, it is very important. However, it is very difficult to do it, because a background and a body color of cars are similar to that of the license plate. In this paper, we propose a new thresholds determination method in the various background by using the real-coded genetic algorithm (RGA). By using RGA, the most likely plate colors are decided under various lighting conditions. First, the average brightness Y values of images are calculated. Next, relationship between the Y value and the most likely plate color thresholds (upper and lower bounds)are obtained by RGA. The relationship between thresholds decided from RGA and brightness average is aproximate by using the recursive least squares (RLS) algorithm. In the case of plate detection, thresholds are decided from these functions.

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제어시점에 따른 차량 안정성 제어 시스템의 제어 경향 (An Investigation of Con01 Threshold of Vehicle Stability Control System)

  • 정태영;이경수
    • 한국자동차공학회논문집
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    • 제13권5호
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    • pp.195-201
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    • 2005
  • In conventional Vehicle Stability Control (VSC) System, a control threshold is designed by average driver characteristics. Despite the stabilizing effort, VSC causes redundancy to an expert driver. An advanced VSC which has flexibility on its control property is proposed in this study. By using lateral velocity estimator, a control threshold is determined on side slip angle and angular velocity phase plane. Vehicle planar motion model based sliding controller is modified with respect to various control thresholds. The performance of the proposed VSC algorithm has been investigated by human-in-the-loop simulation using a vehicle simulator. The simulation results show that the control threshold has to be determined with respect to the driver steering characteristics. A VSC with variable control thresholds would provide an improvement compared to a VSC with a constant threshold.

ATM 스위치 네트워크에서의 2-레벨 임계치를 갖는 셀우선순위 제어방식 (Cell Priority Control with 2-Level Thresholds in ATM Switch Network)

  • 박원기;한치문;최형진
    • 한국통신학회논문지
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    • 제19권3호
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    • pp.479-491
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    • 1994
  • 본 논문에서는 유한 크기의 출력 버퍼를 가진 ATM 스위치에서 셀 지연 요구와 셀 손실 요구를 고려한 2-레벨 임계치를 갖는 우선순위 제어 방식을 제안하였다. 본 논문에서 제안한 우선 순위 제어 방식은 유한크기를 가진 하나의 버퍼에서 두개의 임계치를 두어 손실에 민감한 셀에 대해서는 셀손실률을 개선하고, 지연에 민감한 셀에 대해서는 셀 지연 시간을 개선하는 방법이다. 본 방식에서는 우선순위 제어 방식을 이론적으로 구하고 수치해석을 통해 셀손실률과 평균셀지연을 구하였다. 셀의 서비스 품질 특성에 따라 두개의 임계치를 적절히 조절함으로써 셀손실률 또는 평균셀지연의 개설효과를 얻을 수 있음을 확실히 알 수 있다.

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