Elfege Arthur Leylavergne

Over Height Vehicle Detection — Real-Time Safety System for NYSDOT

Single-handedly architected and delivered production-grade edge-computing safety system — real-time over-height vehicle detection via integrated LiDAR, VCA cameras, and automated traffic control. Owned full stack from application architecture to field hardware configuration.

• Architected fault-isolated multi-process system (5 data processors + Flask app) in single Docker container with 7-layer watchdog architecture; achieved 120+ days continuous uptime.
• Implemented VCA streaming optimization: 18 duplicate detections to 1 optimal output via confidence plateau detection, maintaining ~100MB memory footprint.
• Designed dual-sensor correlation: LiDAR (TCP, millimeter-accurate) + VCA (RTSP classification) with 5-second deduplication and UUID-based video matching.
• Built MQTT/WebSocket distribution for TMC dashboards; AVRO pipeline integration with Apache NiFi.
• Created Express.js admin server in isolated container with SSH proxy for secure TMC remote management.
• Developed automated field installer handling encryption, hardware integration (LiDAR, PTZ, SNMP relays), and system service configuration.
• Engineered PostgreSQL batch operations (100/batch) with 6-day automated retention under 24/7 write loads.

DMS Control API — Highway Dynamic Message Sign Command & Control

Sole architect and developer of a production command & control API for Dynamic Message Signs across multiple state DOT deployments. Reverse-engineered NTCIP 1203 protocol from MIB specifications and IRIS open-source reference to build a vendor-agnostic driver framework — no SDK access provided.

• Designed driver-based architecture with factory/registry pattern: manufacturer-specific SNMP drivers (Daktronics VFC-3000, generic NTCIP), 4-gate request router, 3-tier quirk resolution (device override > model template > defaults).
• Implemented full NTCIP 1203 message lifecycle: MULTI markup validation, CRC computation, message activation sequences, readback verification, and scheduled message management via APScheduler.
• Built interactive API dashboard with live endpoint testing, Mermaid-based architecture diagrams, and field-level contextual help across 15+ endpoints.
• Delivered 31 end-to-end tests, Kafka event streaming integration, and MIB-driven capabilities discovery — all from protocol specs with zero vendor support.

Device Status Monitoring System — Network Infrastructure Monitoring for UDOT

Architected production-grade network monitoring system for Utah DOT, tracking 2,400 devices across 750+ subnets on state fiber infrastructure.

• Achieved 90%+ cycle time reduction (54–60 min to 5–7 min) through device-type filtering and adaptive batching.
• Designed Python asyncio/aiohttp architecture with configurable worker pools (2,000 concurrent pings) preventing file descriptor exhaustion.
• Engineered APScheduler-based per-device-group scheduling with independent intervals (12/24/48 min cycles), 100% adherence.
• Integrated PostgREST streaming writes for real-time visibility; containerized via Docker Compose with AWS (ECR, Secrets Manager, SSO).
• Validated 120+ hours continuous operation, zero errors.

Real-Time Alert Routing System — Event Processing & Notification

Architected real-time alert processing system using Apache Flink and Kafka, dispatching personalized notifications via email, SMS, and WebSocket.

• Designed event-driven architecture processing complex trigger conditions across multiple event types.
• Integrated PostgreSQL with stored procedures for optimized operations; modular dispatch supporting SMTP and Twilio.
• Containerized with Docker Compose; implemented multiprocessing/multithreading for concurrency.

Video-Streaming Platform — Low-Latency DOT Camera Infrastructure

• Built core video-streaming platform: Flask + FFmpeg encoding/compression with WebRTC/HLS delivery.
• Implemented React monitoring interface for real-time stream health and metrics visualization.
• Automated deployment infrastructure via Bash scripting and CI/CD pipelines.

Front-End — DotStream React/Next.js Monorepo

Contributor to production Next.js 15 / React 19 / TypeScript monorepo (Turbo, pnpm workspaces) serving 15+ dashboard pages across multiple state DOT deployments.

• Integrated full OHVD real-time subsystem into the React platform: alert providers, WebSocket event streams, map panel hierarchies, and Kendo data grids.
• Contributed to migration from 5,000+ line vanilla JS monolith to modular React component architecture with Jest unit tests and Playwright E2E coverage.

Anamnesis — Vector-Based Episodic Memory for AI Instances

Designed and built a semantic memory system enabling AI instances to retain and retrieve contextual knowledge across sessions — grounded in epistemological theory of episodic memory.

• Architected FastAPI async backend with MongoDB Atlas Local native $vectorSearch (HNSW, 1024-dimensional embeddings) — zero cloud dependency.
• Built multi-model embedding pipeline (sentence-transformers) with automatic re-embedding on model change, checkpoint-based resumption, and JSONL bulk ingestion.
• Implemented cross-instance coordination: file crawler auto-ingests from handoff buffers, project histories, and CLAUDE.md files across networked machines.
• Integrated streaming chat with memory injection — semantic search before each turn, session persistence with rename history, three LLM backends (Ollama, Claude CLI, Claude API).

MOBIUS.NVR — Multi-Vendor Video Surveillance Platform

Unified NVR managing 17+ IP cameras across 4 vendors and growing (Python/Flask/Docker), with ONVIF/WebRTC/MediaMTX streaming at 200ms latency and Neolink bridging for non-ONVIF devices.

IoT & Home Automation — SmartThings, Hubitat, ESP32

• Reverse-engineered iRobot Roomba 980 WiFi protocol (HTTPS/JSON API/Node.js) — first SmartThings/Hubitat integration, subsequently forked and extended by community developers.
• Thermostat Manager (Groovy): multi-device HVAC automation with narrow-AI learning features.
• Dashboard interface (JavaScript/HTML) for real-time IoT device control.
• IoT firmware (C++): ESP32/ESP8266 smart sensors, remote controllers, window actuator controllers.