Kostas Vasilopoulos
AI/ML Engineer @ Pfizer | Econ (Ph.D.)
Specializing in enterprise ML platforms, MLOps execution, and responsible AI systems
About Me
Machine Learning Engineer & Ph.D. in Economics. The combination sounds odd until you realize that economic modeling and enterprise AI share the same core problem: making decisions under uncertainty with imperfect data. That foundation shapes everything: how I design systems, evaluate tradeoffs, and think about model risk, causal inference, and what "good enough" actually means at scale.
I build and operate enterprise ML platforms and end-to-end AI solutions, from LLM integration and RAG pipelines to MLOps execution patterns, distributed systems, and platform-wide standards for AI service integration, security, and lifecycle management in regulated environments. The goal is always the same: infrastructure and solutions rigorous enough to hold up under real-world constraints, not just controlled conditions. Currently: Senior Manager, Data Science Platform Engineering at Pfizer.
Core Expertise & Skills
AI & Machine Learning
- Generative AI & Large Language Models (RAG, embeddings, fine-tuning)
- Natural Language Processing & Text Analytics
- Production ML Operations & Model Lifecycle (model deployment, versioning, automated pipelines)
- Model Evaluation, Monitoring & Drift Detection
Engineering & Infra
- Programming: Python, R, SQL, JavaScript, C++
- Distributed Computing & Microservices Architecture (horizontally scalable systems, service-oriented architecture)
- Cloud & Containers: AWS, Azure, Docker, Kubernetes
- Scalability & Performance Optimization (throughput optimization, cost reduction, runtime efficiency)
- Web Development & REST APIs
- Data Engineering: ElasticSearch, Postgres, Kafka, NoSQL (search, storage, streaming)
- DevOps: Git, Linux, CI/CD Pipelines
Professional Experience
Pfizer
Senior Manager, Data Science Platform Engineering
- ▸Own the engineering strategy and roadmap for Pfizer's enterprise, cloud-native Data Science & GenAI platform (Dataiku), serving 1,800+ data scientists and analysts and hosting a large portfolio of production Python services and web apps
- ▸Scale LLMOps for 1M+ LLM requests/month, driving cost controls, observability, and access governance across production ML and GenAI workloads
- ▸Architect enterprise GenAI capabilities (LLM integrations, RAG systems, AI assistants) as reusable platform services that accelerate AI adoption across the organization
- ▸Establish engineering standards, reusable frameworks, APIs, and self-service tooling that improve developer experience and model lifecycle governance in regulated environments
- ▸Provide technical leadership across platform, security, data science, and business teams, and manage a direct report
Machine Learning Engineer, Manager
- ▸Technical owner for integrating and scaling Large Language Models (LLMs) on the enterprise Dataiku platform, solving reliability, performance, and compliance constraints hands-on
- ▸Designed MLOps execution patterns for model deployment, monitoring, and access control in production, later adopted as platform-wide standards
- ▸Built reusable platform abstractions and reference implementations for Python services and web apps, driving cross-team adoption of AI capabilities
- ▸Technical Lead for Ethicara ML: designed and delivered responsible AI solutions aligned with enterprise and regulatory standards
- ▸Governed platform usage, onboarding, and operations across users, administrators, and engineering teams
OrosDynamics (formerly SophoTree)
Machine Learning Engineer
Promoted from Data Scientist (06.2021 -- 01.2022)
- ▸Tech Lead for EU Horizon 2020 initiatives (Infinitech, AI4PP), owning end-to-end system architecture, delivery, and long-term technical direction
- ▸Designed and implemented a distributed data collection and processing platform on Kubernetes, horizontally scaling to millions of jobs per day
- ▸Productionized multiple ML models with autoscaling, microbatching, and runtime optimizations, increasing throughput by 320% and cutting infrastructure costs by 40%
- ▸As de facto platform owner, defined reusable ML pipelines and CI/CD, observability, and reliability standards adopted across models, services, and teams
- ▸Built and operated API microservices integrating PostgreSQL, Elasticsearch, and analytics pipelines for real-time and batch workloads
- ▸Led development and deployment of production NLP pipelines using Spark NLP (classification, sentiment analysis, NER), later reused across document and news processing workloads
Data Scientist
- ▸Developed and trained NLP models for large-scale news and document analysis, focusing on classification, sentiment analysis, and entity extraction
- ▸Extended the platform from structured data to unstructured text, laying the groundwork for the production NLP pipelines later scaled as ML Engineer
Lancaster University
Visiting Researcher
- ▸Designed and implemented real-time exuberance detection and predictive modeling systems, translating advanced econometric theory into production-grade open-source software (exuber)
- ▸Delivered 14–150× performance improvements via optimized matrix inversion and numerical methods, enabling real-time processing of large-scale economic datasets
- ▸Work from the Housing Observatory featured in The Times and used by practitioners, including central banks
Teaching Associate
- ▸Taught undergraduate and postgraduate economics courses, consistently receiving outstanding student evaluations
Research Assistant & Graduate Teaching Assistant
- ▸Built analytical models and interactive tools for real-time monitoring of UK national and regional housing markets
- ▸Led web development of the Housing Observatory platform (https://housing-observatory.com/), collaborating with the Federal Reserve Bank of Dallas
- ▸Authored and maintained 6 open-source R packages (exuber, ivx, uklr, onsr, transx, ihpdr) with 100K+ collective downloads
Education, Publications & Awards
Education
Ph.D. in Economics
Lancaster University
2016-2020
M.Sc. in Economics, Applied Finance
University of Macedonia
2014-2016
B.Sc. in Economics
University of Macedonia
2009-2014
Awards & Achievements
Departmental Studentship Award
Lancaster University
2016-2019
MSc Scholarship
University of Macedonia
Awarded based on academic excellence
Selected Publications
Real Estate and Construction Sector Dynamics over the Business Cycle
Vasilopoulos, K., & Tayler, W.
Economica (2026)
Exuber: Recursive Right-Tailed Unit Root Testing with R
Vasilopoulos, K., Pavlidis, E., & Martínez-García, E.
Journal of Statistical Software, 103, 1-26 (2022)
Speculative Bubbles in Segmented Markets: Evidence from Chinese Cross-Listed Stocks
Pavlidis, E.G., & Vasilopoulos, K.
Journal of International Money and Finance, 109, 102222 (2020)
Thesis
Essays in Macroeconomics and Finance
PQDT-Global (2020)
Contact
I'm always open to discussing new projects, opportunities, or collaborations. Feel free to reach out through any of the following channels:
Let's Connect
Whether you want to discuss a project, ask about my experience, or just say hello, I'd love to hear from you.
Academic Work
Looking for my academic research and publications? Visit my academic website
(archived site, no longer maintained)