120 likes | 298 Views
Control Theory in Biology: From MCA to Chemotaxis. Brian Ingalls Tau-Mu Yi Pablo Iglesias. www.xxx.edu (Notes and Slides). What is Control Theory?.
E N D
Control Theory in Biology: From MCA to Chemotaxis Brian Ingalls Tau-Mu Yi Pablo Iglesias www.xxx.edu (Notes and Slides)
What is Control Theory? • “Principles and methods used to design engineering systems that maintain desirable performance by automatically adapting to changes in the environment.” • More specifically, control theory is concerned with designing strategies that ensure the robust performance of a system. • Examples of control systems are everywhere.
Plant Actuator Gas Pedal Output Speed Car Disturbance Controller Driver Press Feedforward Control Disturbances are everywhere! Basic Feedback Control System Goal: Robust performance in the presence of disturbances From Richard Murray
Feedback Input (Glucose) Output (ATP) … … X X X X 0 1 i n perturbation Biological Example of Simple Feedback Control System
Complex Biological Feedback Control System: Heat-Shock Response (Khammash, El-Samad, Gross, Doyle) Heat mRNA Output FF sensor Plant FB sensor Controller DNAK Actuator RNAP DNAK ftsH Lon RNAP DnaK FtsH Lon
What is the Big Deal about Control? • The real world is full of internal and external disturbances. • Complex, high-performance systems are difficult to control. • Instabilities can have catastrophic consequences. • The more complex the system, the more important are issues concerning control. • Control structures contribute greatly to the complexity of real-world systems.
Control Theory and Biology • Biological systems are extremely complex, efficient, robust, and high-performance. • Issues of control are paramount. • Biological networks are dominated by feedback loops. • Control theory is important for both engineering and reverse-engineering feedback systems.
Feedback Control and Disturbance Attenuation Steady-state analysis
Robustness and Sensitivity Function • Measure of inverse robustness (fragility). • Sensitivity of output to disturbance at all frequencies: S(w). • Manipulating S(w) forms the essence of control design.
Outline • Section 1: A Control Theoretic Approach to Metabolic Control Analysis (1 hour) • Section 2: Integral Feedback Control: From Homeostasis to Chemotaxis (1 hour) • Section 3: Intercellular Communication: Uses of Positive and Negative Feedback (1 hour)