• Title/Summary/Keyword: 시간 지연 제어

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Digital variable structure control of a hot-water heating control system with long dead time (긴 지연시간을 갖는 온수난방 제어시스템의 디지틀 가변구조제어)

  • 안병천;장효환
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.232-237
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    • 1991
  • Digital Variable Structure Controller(DVSC) is proposed to control variable speed recirculating pump for hot-water heating control system. In this study, nonlinear sliding line is used beyond output error boundary layer and PID sliding line is used within the layer. For long dead time compensation, constraint is added to Smith predictor algorithm. Steady state error is eliminated by using the proposed sliding line in spite of heating load change. By decreasing sampling time, good sliding motion is yielded but system output noise bv flow dynamics is amplified.

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Design of Automatic Diameter Controller for Crystal Grower-FF CZ150 (Crystal Grower -FF CZ150의 자동 직경 제어기 설계)

  • 양승현;박종식;이석원
    • Proceedings of the KAIS Fall Conference
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    • 2003.06a
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    • pp.211-214
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    • 2003
  • 본 연구에서는 실리콘 웨이퍼 제조 현장에서 사용 중인 단결정 실리콘 성장기의 자동 직경 제어기를 2계 근사 모델을 이용하여 설계하고 시간지연 보상기를 적용함으로써 결정봉의 직경과 인상 속도를 최적화하여 결정봉의 제품에 직접적인 영향을 주는 결정 결함 및 언더나 오버의 직경 이상을 줄이고 제품의 질과 수율을 향상시킬 수 있다. 또한 기존의 자동직경제어시스템의 고전적인 제어기를 보완함으로써 결과적으로 생산량 증가 및 제품의 질 향상에 이바지를 하고 새로이 요구되는 고객의 신기술 요구에 대한 현 장비의 제한성을 극복하는데 큰 기여를 할 것으로 기대 된다.

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An Adaptive Batching Scheduling Policy for Efficient User Services (효율적인 사용자 서비스를 위한 적응적 배칭 스케줄링 정책)

  • Choe, Seong-Uk;Kim, Jong-Gyeong;Park, Seung-Gyu;Choe, Gyeong-Hui;Kim, Dong-Yun;Choe, Deok-Gyu
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.37 no.2
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    • pp.44-53
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    • 2000
  • The waiting delays of users are inevitable in this policy since the services are not taken immediately upon requests but upon every scheduling points. An inefficient management of such delays makes an unfair service to users and increases the possibility of higher reneging rates. This paper proposes an adaptive batch scheduling scheme which improves the average waiting time of users requests and reduces the starvation problem of users requesting less popular movies. The proposed scheme selects dynamically multiple videos in given intervals based on the service patterns which reflect the popularity distribution(Zipf-distribution) and resource utilizations. Experimental results of simulations show that the proposed scheme improves about 20-30 percentage of average waiting time and reduces significantly the starving requesters comparing with those of conventional methods such as FCFS and MQL.

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Setting Time Evaluation on Cement Paste with Retarder Using Non-Destructive Measurements (비파괴 측정법을 이용한 지연제 첨가 시멘트 페이스트의 응결 평가)

  • Ahn, Yu-Rhee;Jun, Yu-Bin;Yim, Hong Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.4
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    • pp.48-56
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    • 2022
  • Controlling the setting time of cementitious materials is one of the most important factors in securing early-age performance of concrete structures. Recently, the use of retarding admixtures, which enable the inhibition of some hydration products to control the securing time due to average temperature rise is suggested. Although various non-destructive evaluation methods have been proposed to evaluate cement hydration and hardening of cement-based materials to overcome the limitations of Vicat needle test, experimental research is still required to use the non-destructive evaluation method with added retarding admixtures. In this study, measurements of electrical resistivity and ultrasonic wave velocity in early-aged cement pastes were performed according to the addition of retarding admixture(tartaric acid). The setting time of the cement pastes was evaluated by obtained rising time of the both non-destructive measurements. As a result, the possibility of evaluating the setting delay in cement pastes was confirmed through comparative analysis with the initial and final setting times by Vicat test. In addition, X-ray diffraction results at the rising time of electrical resistivity showed a key hydration product affecting the setting delay.

Tension Control of a Winding Machine using Time-delay Estimation (시간 지연 추정 기법을 이용한 권취기의 장력 제어 알고리즘)

  • Heo, Jeong-Heon;You, Byungyong;Kim, Jinwook
    • Journal of Drive and Control
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    • v.15 no.3
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    • pp.21-28
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    • 2018
  • We propose a tension controller based on a time-delay estimation (TDE) technique for a winding machine. Firstly, we perform the necessary calculations to derive a mathematical model of the winding machine. In this sense, it is revealed that the roll radius of the winding machine is characteristically seen to be increasing or decreasing during the winding process. That being said, it is noted that the parameters of the winding machine are coupled and constantly changing during this process. Understandably then, it is noted that the model is shown to be nonlinear and time-varying. Secondly, we propose the way to apply the TDE based controller which is the so-called Time-delay Control (TDC). The TDC utilizes the time-delayed information intentionally to compensate the nonlinear and time-varying characteristics. As we have seen, the proposed controller consists of two parts: one is a TDE component, and the other is an error dynamics component which is defined by a user. In a computer simulation based on the Matlab/Simulink program, the proposed controller is compared with a conventional PID controller, which is widely used in the tension control of the winding machine. The proposed controller reduces the incidence of overshoot and steady-state error in the tension control, as compared to the conventional PID controller.

A Representation for Multithreaded Data-parallel Programs : PCFG(Parallel Control Flow Graph) (다중스레드 데이타 병렬 프로그램의 표현 : PCFG(Parallel Control Flow Graph))

  • 김정환
    • Journal of KIISE:Computer Systems and Theory
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    • v.29 no.12
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    • pp.655-664
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    • 2002
  • In many data-parallel applications massive parallelism can be easily extracted through data distribution. But it often causes very long communication latency. This paper shows that task parallelism, which is extracted from data-parallel programs, can be exploited to hide such communication latency Unlike the most previous researches over exploitation of task parallelism which has not been considered together with data parallelism, this paper describes exploitation of task parallelism in the context of data parallelism. PCFG(Parallel Control Flow Graph) is proposed to represent a multithreaded program consisting of a few task threads each of which can include a few data-parallel loops. It is also described how a PCFG is constructed from a source data-parallel program through HDG(Hierarchical Dependence Graph) and how the multithreaded program can be constructed from the PCFG.

Adaptive Error Recovery in cdma2000 1xEV-DO Broadcast and Multicast Networks (cdma2000 1xEV-DO를 위한 모바일 브로드캐스트/멀티캐스트 네트워크에서의 능동적인 에러 교정 방법에 관한 연구)

  • Kang Kyungtae;Park Hosang;Cho Yongwoo;Shin Heonshik
    • Journal of KIISE:Information Networking
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    • v.33 no.1
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    • pp.91-102
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    • 2006
  • We analyze the performance of MAC-layer Reed-Solomon error recovery in the cdma2000 1xEV-DO Broadcast and Multicast Services (BCMCSs) environment, with respect to the size of the ECB (Error Control Block) and the air-channel condition, and establish the relationship between ECB size, error recovery capacity and service latency. From this we propose an adaptive error recovery scheme which adjusts the size of the ECB to reflect the environment of the mobile nodes so as to meet the required service quality (target bit error-rate), while reducing the latency of real-time applications. Extensive simulation results show the effectiveness of our approach compared to the current static scheme. Proposed adaptive schemes achieves near optimal solution with respect to service latency while satisfying the required service quality.

A TCP Flow Control for Receiver with Limited Memory in Mobile Environment (모바일 환경에서 제한된 메모리의 수신자에 의한 TCP흐름 제어)

  • 이종민;차호정
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.04d
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    • pp.512-514
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    • 2003
  • 본 논문은 모바일 환경에서 제한된 메모리를 가지고 있는 수신자에 의 한 TCP흐름 제어 방법을 제안한다. TCP 흐름 제어는 송신자에서 수신자에게 전달되는 Advertised 윈도우 크기를 조정하여 수행된다. 수신자는 무선 대역폭과 종단간 패킷 왕복 시간을 동적으로 측정하며 최적의 Advertised 윈도우 크기를 계산하고 송신자의 전송률을 무선 대역폭으로 제한한다. 제안된 흐름 제어 기법은 제한된 메모리를 가진 수신자를 고려하였으며 무선 네트웍의 특성을 고려 한 효율적 인 TCP 흐름 제어로 TCP의 전송 성능 향상과 종단간 패킷 왕복 시간의 지연을 줄일 수 있도록 하였다. 제안된 흐름 제어 기 법의 효율성과 성능을 구현과 실험을 통해 검증한다.

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Multiple Conference Servers Architecture using Extended Control Channel Framework (확장 제어 채널 프레임워크를 사용한 다중 컨퍼런스 서버 구조)

  • Jang, Choonseo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.7
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    • pp.1335-1341
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    • 2017
  • In this paper, a new architecture of multiple conference servers which use extended control channel framework in SIP(session initiation protocol) session has been presented. For this purpose, in this study, a new extended control channel framework architecture which can distribute total conference system loads to multiple servers effectively has been presented. In the implementation, extended control channels have been connected by using SIP sessions that was established between each conference servers, and extended control channel messages which can be transferred through control channels have been designed in this study. These extended control channel messages can distribute system load effectively between multiple conference servers, and conference information data format that can represent extended control channel framework has also been designed. Furthermore, exchange procedures of extended control channel messages have also been presented. The performance of the proposed system has been analysed by simulation. The analysis results show that average SIP messages delay time and average media stream delay time have improved.

Development of Multi Haptic Control Environments for Tele-operating Robot System (로봇 원격조종을 위한 멀티 햅틱 제어 환경 개발)

  • Choi, You-Rak;Lee, Jae-Cheol;Kim, Jae-Hee;Kim, Seung-Ho;Kwon, Oh-Seok
    • Journal of Korea Multimedia Society
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    • v.16 no.6
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    • pp.689-699
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    • 2013
  • There are four methods such as 1:1, 1:N, N:1, and N:N in the tele-operating system for control the remote side robot. The operator must know the information of surroundings of the robot, collision possibility of the mobil equipment, and force feedback of the manipulator. The time delay problem occurs in the tele-operating and it causes vibration and expressive power of the manipulator owing to bidirectional force feedback. N:N control technique having been developed lately has a switching algorithm for the operator to select the target robot or it's partial equipment. When multi-operators work together to accomplish a task with multi-robots, the switching facility must be offered. And the automatic tuning skill to generalize the operator's tendency is needed also. We describes the methodologies and skills for developing a haptic-based tele-operating environments to makes it possible to control the remote multi-robots with multi-operators in this paper.