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GiZano edited this page Aug 5, 2026 · 3 revisions

Glossary of Terms

  • Anti-Replay Attack: A security mechanism that validates the timestamp of an incoming telemetry packet. QuakeGuard enforces a strict 60-second window to prevent attackers from recording and re-transmitting old earthquake signals.
  • Dead Letter Queue (DLQ): A Redis list (ai_report_queue_dlq) receiving AI report jobs that fail unrecoverably (missing report, persistent inference errors). Events pushed there mark the corresponding report FAILED.
  • DSP (Digital Signal Processing): The manipulation of analog information in digital form. On the ESP32, this includes applying a High-Pass Filter (HPF) to the ADXL345 readings to remove the DC offset caused by gravity.
  • ECDSA (Elliptic Curve Digital Signature Algorithm): The cryptographic protocol used by QuakeGuard to prove the identity of a sensor. We use the NIST P-256 curve.
  • EmergencyReport: The persisted state-machine entity representing an AI-generated report for a confirmed alert, transitioning PENDING → COMPLETED | FAILED. See AI Emergency Report Service.
  • NVS (Non-Volatile Storage): The flash memory segment of the ESP32 used to permanently store the sensor's private key, network credentials, and assigned sensor_id across reboots.
  • Ollama: The self-hosted LLM runtime used by QuakeGuard (v1.2.0) to generate emergency reports entirely on-premise. See AI Emergency Report Service.
  • PGA (Peak Ground Acceleration): A measure of earthquake acceleration on the ground. Used in QuakeGuard to estimate the physical magnitude of an event.
  • PostGIS: A spatial database extender for PostgreSQL. It allows QuakeGuard to run complex geographic queries (like ST_Contains) to automatically assign sensors to macro-regions.
  • STA/LTA (Short-Term Average / Long-Term Average): The industry-standard algorithmic trigger for seismic events. It compares a short rolling window of acceleration (detecting sudden changes) against a longer rolling window (the baseline noise floor).
  • Thundering Herd Problem: A scenario where a massive number of clients (in our case, thousands of IoT sensors feeling an earthquake simultaneously) send requests to a server at the exact same time, potentially causing a bottleneck or crash. Handled in QuakeGuard via Redis queuing.
  • Zero-Trust: A security framework requiring all users/devices, whether inside or outside the network, to be authenticated, authorized, and continuously validated.

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