How Models of Feedback Systems can Help the Practical Biologist
The fundamental importance of feedback systems -- especially regulatory feedback systems -- is universally recognized by engineers and biologists alike. In order to regulate the temperature of a room, the engineer links together certain well-defined components (thermostat, electrical relay, oil burner, air-circulating fan) to make a feedback loop. An important feature of such man-made loops is that they are actuated by error, defined as the difference between the actual value of the regulated variable (here room temperature) and the desired or setpoint value (here the chosen setting of the thermostat). As the room cools, the error soon becomes large enough to be sensed by the thermostat, the thermostat signals the furnace to fire, hot air is circulated, and the room warms up until the error becomes small enough to turn off the thermostat again. Engineers have developed a powerful array of mathematical techniques which allow them to analyze in detail the time-dependent behaviour of such regulatory systems, and to predict how well the system will perform under a variety of circumstances.
KeywordsBurner Obesity Furnace Iodide Expense
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- Aurbach, G. D. and Phang, J. M. (1974). “Vitamin D, parathyroid hormone, and calcitonin”. Chapter 70 in Medical Physiology, Vol. 2, 13th Edition (Mountcastle, V. B., Editor) C. V. Mosby, St. Louis.Google Scholar
- Riggs, D. S. (1970). “Control Theory and Physiological Feedback Mechanisms”. Williams and Wilkins, Baltimore.Google Scholar
- Stear, E. B. (1973). “Systems theory aspects of physiological systems”. pp. 496–500 in Regulation and Control in Physiological Systems, (Iberall, A. S. and Guyton, A. C., Editors), Proceedings of a Conference. International Federation of Automatic Control. ( Distributed by the Instrument Soc. of America. )Google Scholar
- Tucker, V. A. (1975). “The Energetic Cost of Moving About”. American Scientist 63, 413–419.Google Scholar
- Walter, C. (1975) in “Enzyme Reactions and Enzyme Systems”. Enzymology Series, Number 4. Marcel Dekker, New York.Google Scholar