Brittle systems theory creates an analogy between communication theory and mechanical systems. A brittle system is a system characterized by a sudden and steep decline in performance as the system state changes. This can be due to input parameters that exceed a specified input, or environmental conditions that exceed specified operating boundaries. This is the opposite of a gracefully degrading system. Brittle system analysis develops an analogy with materials science in order to analyze system brittleness.[1] A system that is brittle (but initially robust enough to gain at least some foothold in the marketplace) will tend to operate with acceptable performance until it reaches a limit and then degrade suddenly and catastrophically. The table below illustrates the concept behind the analysis using an example of a communication system.
| Materials Science | Target System | Brittle Systems Analysis | Materials Science Quantification | | Stress | Interbyte jitter, EMI, number of slaves, etc.… | Amount parameter exceeds tolerance | Force per unit area within a body |
| Toughness | Ability to withstand the above | System robustness | Ability to absorb energy up to failure |
| Hardness* | Constant latency, throughput with stress in tolerance | Level of performance within tolerance | Resistance to deformation |
| Ductility* | Gradual reduction in latency, throughput as stress exceeds tolerance | Level of performance out of tolerance | Fracture strain or reduction of area at fracture |
| Plastic strain | Latency, throughput are permanently degraded | System cannot recover from degradation | Deformation between particles in a body relative to length |
| Reversible strain | Latency, throughput are temporarily degraded | System can recover from degradation | Same as above, but returns to normal after force removed |
| Brittle fracture | Sudden steep decline in latency, throughput | Sudden steep decline in performance | There is no reduction of area when material breaks |
| Ductile fracture | Graceful degradation in latency, throughput | Graceful degradation in performance | The area at the point of fracture gradually reduces to zero |
| Brittleness* | Hardness over ductility | Ratio of hardness over ductility | Ratio of hardness over ductility |
| Deformation | Degradation in latency, throughput | Degradation in performance | Change in shape of a material |
| Young's modulus | Stress (jitter/EMI) over reduction in latency and throughput | Amount of tolerance exceeded over degradation | Measure of the stiffness of an elastic material |
|
1. ^Stephen F. Bush, John Hershey and Kirby Vosburgh, Brittle System Analysis, [https://arxiv.org/pdf/cs/9904016.pdf]