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Week 7 — Stress Testing SustainHub: Resilience Quotient and System Robustness

Week 7 — Stress Testing SustainHub: Resilience Quotient and System Robustness

Week 7: Stress Testing SustainHub — Resilience Quotient and System Robustness

This week, we focused on taking the next major step in our evaluation pipeline — measuring resilience. While last week was about maintaining harmony in ideal conditions, Week 7 was about understanding how the system behaves under stressful, imbalanced, and uncertain environments.


Key Highlights

  • Introduced Resilience Quotient (RQ) as a formal metric
  • Simulated task surges and role removals to stress-test the system
  • Visualized system recovery and agent adaptability
  • Logged SARSA agent behavior under constrained conditions

1. What is the Resilience Quotient?

The Resilience Quotient (RQ) measures the system’s ability to:

  • Absorb disruptions (e.g., sudden increase in tasks or agent dropouts)
  • Recover performance after a shock
  • Maintain fairness and task completion under non-ideal conditions

Think of RQ as the community’s immune system: how quickly and effectively can it bounce back?

RQ Formula (simplified):

RQ = (1 - ΔHI) * RecoveryRate

Where:

  • ΔHI = Drop in Harmony Index after disruption
  • RecoveryRate = Speed at which HI returns to baseline
  • RQ ∈ [0, 1], with 1 being highly resilient

2. Stress Test Scenarios

We designed two primary tests:

A. Role-Based Agent Dropout

  • Randomly disabled a subset of agents (e.g., all Maintainers)
  • Observed reallocation behavior and backup performance from Contributors

B. Task Surge Injection

  • Tripled the number of incoming tasks for 3 consecutive steps
  • Measured how quickly agents adapted and balanced the load

3. What We Observed

After 10 simulation steps (with disruptions applied in steps 4–6):

  • Harmony Index initially dropped from 0.82 → 0.64
  • Recovered to 0.78 by step 10
  • Calculated Resilience Quotient: 0.743

Key Insights:

  • SARSA agents adapted with a brief learning lag
  • Task rebalancing via MAB was slower during role-specific dropouts
  • Fairness dipped briefly but recovered as agents diversified actions

4. Logging and Debugging Enhancements

To better monitor recovery:

  • Added RQ logs to simulation.py
  • Logged action-value updates from Q-tables during stress
  • Plotted HI recovery curves across different stress levels

All relevant logs are stored under data/logs/ and visual outputs in data/plots/.


Next Steps

  • Introduce reward shaping to encourage quicker recovery
  • Evaluate long-term fatigue or agent burnout
  • Refactor simulation for episodic stress testing (controlled trials)
  • Add toggle flags for stress mode in the UI/CLI

Summary

Week 7 gave us critical insights into SustainHub’s resilience and adaptability. By simulating stress conditions and measuring RQ, we are now able to not only ensure smooth operation during normal conditions — but also ensure the system can bounce back under pressure.

Next week, we’ll explore dynamic reward tuning and meta-learning techniques to make the agents even smarter under stress.

Stay tuned!

This post is licensed under CC BY 4.0 by the author.