Machine Learning Engineer & Researcher
BSc Computer Science · National & Kapodistrian University of Athens
Building end-to-end ML systems with Docker, CI, observability, and live demos — from research to reproducible pipelines.
Open to junior ML / MLE roles · 🇨🇦 Canadian work-authorized (open permit — no sponsorship needed) · Athens, Greece → Toronto
| Role | Organization | Period | Impact |
|---|---|---|---|
| Head Engineer | Paphos Medical Association | Jun 2022 – present | AsklepiosMed platform serving 480 doctors · 99.5% uptime over 12 months · deploy cycle 2 days → 15 minutes |
| Full-Stack Engineer | Medihyal Clinic | Jan 2025 – present | Booking platform, 200+ monthly reservations · Groq LLM integration reduced manual review time by 80% |
| Paper | Status | Result | Links | |
|---|---|---|---|---|
| 🔬 | CEGVR — LLM + Z3 SMT Verifiable Reasoning | Manuscript · solo author | 90.6% certified accuracy (+50 pts vs baseline) · 7 500 eval runs · Qwen3-30B-A3B on A100 | 📄 PDF · 💻 Code · 🔬 Demo |
| 🔭 | DynaDiff-VLBI — Dynamic Radio Interferometric Imaging | Manuscript · solo author | EHT benchmark · 3D U-Net with test-time optimization | 📄 PDF · 💻 Code |
| 🏥 | TrustQueryNet — Trustworthy Medical Image Classification | Manuscript · solo author | 83.5% acc on HAM10000 · calibrated selective prediction · ConvNeXt-Tiny | 📄 PDF · 💻 Code |
| ⚡ | Speculative Decoding Study — LLM Inference Optimization | Manuscript · solo author | 1.46× speedup · vLLM + EAGLE-3 · A100 80 GB | 📄 PDF · 💻 Code |
🔴 Graph Fraud GNN · Hybrid heuristic + PyTorch GNN scoring. 14 graph-context features, 457 req/s, p95 = 3.3 ms. Live: Simulate transactions → Score → Threshold slider
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🛡️ Realtime Fraud Guard · Streaming cross-channel scoring. ROC-AUC 1.0 on holdout. Payments + SMS + email. Live: Pick channel → Safe/Fraud preset → Score event
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Graph-native AML triage. 3 061 nodes, 51 758 edges, ROC-AUC 0.87. Path-level explanations. Live: Type node ID → Score + ego metrics + neighbors
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Real-time GTFS-RT + online ML (River). 1 000+ stations, 10s auto-refresh. Live: Click route pills (1, A, N…) → Filter anomaly feed
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🧪 CEGVR — LLM+SMT · 90.6% certified accuracy via Z3 UNSAT-core feedback. 7 500 eval runs on A100. Live: Interactive results viewer — click each arm → breakdown
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PHI/PII redaction. 20+ entity types, per-label mask/hash/redact policies. Live: Interactive studio with side-by-side redaction
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📒 DoubleX Ledger · SERIALIZABLE double-entry ledger. Idempotent postings, FX settlement, 94% coverage. Live: Post → Replay same key → Balance unchanged
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⚡ LimitForge RLS · 4-algorithm rate limiter. Atomic Redis Lua scripts. 90% coverage. Live: Pick algorithm → Fire 1-25 parallel calls → Watch bars
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7 paradigms compared: CNN, Transfer Learning, SimCLR, CLIP, LoRA. 98.37% best accuracy. LoRA: 98.22% with only 0.36% trainable params
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More projects at stelioszach.com — including clinic systems, medical association platforms, and ongoing research. |
Every project above has a live demo, CI pipeline, and reproducible setup.



