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stelioszach03/README.md

Stelios Zacharioudakis

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.

Portfolio Paper LinkedIn Email


Open to junior ML / MLE roles · 🇨🇦 Canadian work-authorized (open permit — no sponsorship needed) · Athens, Greece → Toronto

💼 Experience

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%

🧠 ML / DL

⚙️ Engineering

📄 Research — 4 papers, all with code + reproducible pipelines

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

🚀 Projects & Live Demos — 8 projects, all with live demos + CI pipelines

🔴 Graph Fraud GNN · CI

Hybrid heuristic + PyTorch GNN scoring. 14 graph-context features, 457 req/s, p95 = 3.3 ms.

Live: Simulate transactions → Score → Threshold slider

PyTorch GNN FastAPI Prometheus Grafana

🛡️ Realtime Fraud Guard · CI

Streaming cross-channel scoring. ROC-AUC 1.0 on holdout. Payments + SMS + email.

Live: Pick channel → Safe/Fraud preset → Score event

Kafka gRPC Redis Streams Prometheus

🕵️ AML Graph Investigator · CI

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

LightGBM NetworkX Neo4j React

🚇 NYC Subway Anomaly · CI

Real-time GTFS-RT + online ML (River). 1 000+ stations, 10s auto-refresh.

Live: Click route pills (1, A, N…) → Filter anomaly feed

River TimescaleDB Next.js Mapbox

🧪 CEGVR — LLM+SMT · CI

90.6% certified accuracy via Z3 UNSAT-core feedback. 7 500 eval runs on A100.

Live: Interactive results viewer — click each arm → breakdown

Z3 Solver vLLM Qwen3-30B-A3B A100

🔒 DeID Privacy Studio · CI

PHI/PII redaction. 20+ entity types, per-label mask/hash/redact policies.

Live: Interactive studio with side-by-side redaction

spaCy NER Celery FastAPI

📒 DoubleX Ledger · CI

SERIALIZABLE double-entry ledger. Idempotent postings, FX settlement, 94% coverage.

Live: Post → Replay same key → Balance unchanged

SQLAlchemy PostgreSQL Prometheus Grafana

⚡ LimitForge RLS · CI

4-algorithm rate limiter. Atomic Redis Lua scripts. 90% coverage.

Live: Pick algorithm → Fire 1-25 parallel calls → Watch bars

Redis Lua PostgreSQL FastAPI

🛰️ EuroSAT DL Benchmark

7 paradigms compared: CNN, Transfer Learning, SimCLR, CLIP, LoRA. 98.37% best accuracy.

LoRA: 98.22% with only 0.36% trainable params

PyTorch SimCLR CLIP LoRA EfficientNet

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.

🌐 stelioszach.com · 💼 LinkedIn · 📧 stelios@stelioszach.com

Pinned Loading

  1. colab-speculative-decoding-speed-lab colab-speculative-decoding-speed-lab Public

    Empirical study of speculative decoding on A100 80GB: 1.46x speedup with vLLM + EAGLE-3. Reproducible Colab notebook + LaTeX paper.

    Jupyter Notebook

  2. graph-fraud-command-center graph-fraud-command-center Public

    Real-time graph fraud detection with hybrid heuristic + PyTorch GNN scoring. 457 req/s, p95=3.3ms. Live interactive dashboard.

    Python

  3. TrustQueryNet TrustQueryNet Public

    Trustworthy medical image classification: noise-robust ConvNeXt-Tiny with 83.5% accuracy, calibrated selective prediction, HAM10000 + ISIC 2019.

    Python

  4. llm-smt-verifiable-reasoning llm-smt-verifiable-reasoning Public

    LLM + Z3 SMT formal verification: 90.6% certified accuracy via conflict-directed search. 50-point lift over one-shot. Paper + 7500 eval runs.

    Python