0100488993

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SYSTEMS ANALYSIS OF LIFE SUSTAINED FUNCTIONS BY BLEEDING

English (英語)

The Kobe journal of the medical sciences

18(2)

79-96

1972-06

The complexity of living systems makes selection either a construction of discrete subsystems studied in detail or an overall analysis of a large part of the system. The former leads to an increase in the complexity of the abstract system. In this paper it will be shown that large subsystems functionally isolated by an input variable, bleeding volume, can be analysed as relatively simple abstract systems which enable an accurate prediction of the behavior of the life sustaining systems. Static, transient and frequency characteristics were obtained by a relation between an input and an output. A backward path gain played an important role on the hyperbolical change of an open loop gain against bleeding volume with every regard to constancy of a forward path gain. When time constant obtained from the transient response of the system was 13 sec., it responded like a first order system, but in a case of 8 sec., it behaved like an underdamped system. Thus, time constant is an index of conformability and stability of the systems. The systems under study were quite stable by the aid of Bode 'plots and Nyquist plots obtained from frequency analysis. Due to an unknown condition of the biological systems, the 'systems showed a characteristics of a second order system or a first order lead-lag system. A possibility was discussed that made a negative feedback system behave like a positive feedback performance by changing the backward path gain or time constant.

bleeding

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