Biomedical Engineering Reference
In-Depth Information
4.1
HOW DISTRIBUTED FEEDBACKS FROM
MULTIPLE SENSORS CAN IMPROVE SYSTEM
PERFORMANCE: IMMUNOLOGY AND
MULTIPLE-ORGAN REGULATION
Lee A. Segel
Department of Computer Science and Applied Mathematics,
Weizmann Institute of Science, Rehovot, Israel
Complex physiological entities such as the immune system can be regarded as possessing
multiple goals. Sensors reflect information on goal performance as well as general
physiological state. As is illustrated here with a simple immunological model, in a dis-
tributed and generalized version of classical feedback this information can be used to im-
prove system goal attainment. In the immune system it is cytokines that transmit the
sensory information. The concept of distributed feedback to improve multiple-goal per-
formance is shown to be of possible relevance to multiple organ dysfunction syndrome
and its therapy.
1.
INTRODUCTION
The human immune system is composed of about a trillion cells. There are
dozens of cell types and hundreds of signalling chemicals. The immune system
plays a variety of homeostatic roles, such as helping to direct wound healing, but
its main job is controlling the myriad pathogens that roam the body. Pathogens
do not passively await immune destruction; they have evolved various evasive
Address correspondence to: Lee A. Segel, Department of Computer Science and Applied Mathemat-
ics, Weizmann Institute of Science, Ziskind Building #24, 76100 Rehovot, Israel (lee.segel
@weizmann.ac.il). [See acknowledgments, p. 435.]
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