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johnantonn/README.md

About me

I'm trying to optimize a notoriously complex loss function, navigating a high-dimensional, non-convex landscape—one small step at a time. Probably, so are you!

My learnings from this winding journey:

  • Choose your objective with caution—you drift toward whatever you optimize.
  • Curate what you train on—you learn from what you keep feeding yourself.
  • Set the pace—bold enough to move, small enough not to overshoot.
  • Favour signal over noise—small, informative steps beat thrashing.
  • Rein in the extremes—when gradients explode, nobody benefits.
  • Beware tunnel vision (overfitting)—a little regularization keeps you adaptable.
  • Use momentum—keep going; let earlier progress carry you through flat stretches.

Education

I hold an MEng in Electrical and Computer Engineering (2015, top 3% of my class) from Aristotle University of Thessaloniki, Greece, and an MSc in Artificial Intelligence (2022, magna cum laude) from KU Leuven, Belgium. I was fortunate to learn from outstanding professors and mentors in mathematics, physics, engineering, and computer science.

I have authored two papers:

Experience

My professional career started in 2015, when I joined the Centre for Research and Technology Hellas (CERTH) as a research associate (Nov 2015–Jul 2016). There, I contributed to an EU-funded H2020 project on cloud computing—when the field was still in its early stages—and worked with a large consortium of European institutions.

I continued as a software engineer at Veltio (Dec 2016–Jul 2018), an Oracle partner offering supply-chain automation solutions. I worked on real-world, large-scale problems alongside an exceptional team and led the development of data pipelines and systems used by major international retailers, including Sainsbury's in the UK.

I then joined the Intelligent Systems and Software Engineering Lab (ISSEL) at the Department of Electrical and Computer Engineering, AUTH, as an ML research engineer (Oct 2018–Sep 2021). I was the technical lead on an EU-funded project on energy monitoring and load disaggregation: applied ML research, NLP pipelines (e.g. BERT, topic models), and a high-throughput event streaming engine for real-time smart-meter analytics.

In September 2022 I joined Expedia Group in London as a machine learning scientist. On the Content & Relevance team I work on large-scale ranking and retrieval—reviews, amenities, and property understanding—using deep learning, LLMs, and multimodal methods. My recent work has included cross-brand review ranking, semantic relevance and distillation for low-latency embeddings, LLM-as-judge labelling, internal TensorFlow ranking frameworks shared across teams, distributed evaluation tooling, and research on bias, calibration, and data pruning.

*My first job was in 2011, during my second year at AUTH, as a part-time support representative at OTE, the largest telecommunications company in Greece.

What motivates me

I find it exciting to push human boundaries with technology, and I believe we have a responsibility to leave the world better for future generations.

All it takes is one small step at a time!

Selected GitHub repositories

Past side projects, coursework, and research code live in separate repositories. Most are archived on GitHub (read-only snapshots; not actively maintained).

Personal notebooks & experiments (self-directed; not part of a degree curriculum)

KU Leuven — Master of Artificial Intelligence

Coursework

Thesis & published research

  • cash-for-unsupervised-ad — Master’s thesis code extended to the LIDTA 2022 (ECML/PKDD) paper: CASH / AutoML for unsupervised anomaly detection

Aristotle University

Diploma thesis

  • insight-qa — Semantic question answering (Java, Elasticsearch, LDA)

Coursework

Curriculum vitae

You can find my full CV here.

Contact

You can contact me by email or on LinkedIn.

Pinned Loading

  1. cash-for-unsupervised-ad cash-for-unsupervised-ad Public archive

    CASH / AutoML experiments on validation-set design for unsupervised anomaly detection (LIDTA 2022).

    Python 3

  2. bias-variance-decomposition bias-variance-decomposition Public archive

    Bias–variance decomposition for classification and regression with mlxtend.

    Jupyter Notebook

  3. fair-binary-classification fair-binary-classification Public archive

    Fairness-aware Adult income prediction with scikit-learn and IBM AIF360.

    Jupyter Notebook

  4. gaussian-bandits gaussian-bandits Public archive

    Gaussian multi-armed bandits and action-selection rules (RL-style notebook).

    Jupyter Notebook

  5. locality-sensitive-hashing locality-sensitive-hashing Public archive

    LSH + MinHash on Stack Overflow posts—similar-question detection in Java.

    Java