• Title/Summary/Keyword: series/parallel/cascade operation

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Derivation of the Timing Constraints for Multi-Sampled Multitasks in a Real-Time Control System (다중샘플링 다중작업을 수행하는 실시간제어시스템의 시계수제한성 유도)

  • 이대현;김학배
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.2
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    • pp.145-150
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    • 1999
  • A real-time control system, composed of the controlled processor and the controller computer(s), may have a variety of task types, some of which have tight timing-constraints in generating the correct control input. The maximum period of those task failures tolerable by the system is called the hard deadline, which depends on not only fault characteristics but also task characteristics. In the paper, we extend a method deriving the hard deadline in LTI system executing single task. An algorithm to combine the deadlines of all the elementary tasks in the same operation-mode is proposed to derive the hard deadline of the entire system. For the end, we modify the state equation for the task to capture the effects of task failures (delays in producing correct values) and inter-correlation. We also classify the type of executing the tasks according to operation modes associated with relative importance of correlated levels among tasks, into series, parallel, and cascade modes. Some examples are presented to demonstrate the effectiveness of the proposed methods.

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A Study on the High Efficiency Ground Source Heat Pump System (1) (부하추종형 고효율 지열히트펌프 시스템에 관한 연구 (1))

  • Koh, Deuk-Yong;Kim, Ook-Joong;Choi, Sang-Kyu;Chang, Ki-Chang
    • New & Renewable Energy
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    • v.1 no.4 s.4
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    • pp.30-37
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    • 2005
  • Cycle simulation of Ground Source Heat Pump[GSHP] system was carried out to determine the design specification of basic components such as turbo compressor and heat exchangers. Part load operation characteristics of the designed GSHP system was estimated using the compressor and heat exchanger performance data. A 50RT class turbo compressor for GSHP system is now under development, in which R134a refrigerant is adopted as working fluid. The compressor with variable cascade diffusers is designed to work both in cooling and heating modes so that it can actively keep up with the climate change with high efficiency. The normal running speeds of the compressor are 59000rpm for heating mode and 70000rpm for tooling mode respectively. It has two identical impellers at both ends of the rotor so as to minimize aero-induced thrust force effectively. GSHP system was coupled with a vortical type heat exchanger, and heat gain and heat loss from ground were evaluated per a bore hole. For the optimal integration of the heat pump system, its header for circulating fluid was combined with the ground heat exchangers in parallel and series configuration.

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