Updated: 2 Jul 2017



Digital personal companions/friends/assistants, large-scale distributed systems, knowledge representation and reasoning, reactive computing, big data processing, cloud computing, graph stores, web services, system architecture, software design and engineering.


  • Architecture, development, execution, and technical leadership in multiple key projects (Cortana personal digital assistant with 150M monthly active users, Xbox One speech/language understanding through Kinect, Reactor large-scale/distributed/reliable stream processing system responsible for the evaluation of billions of messages over 10s of millions of subscriptions, knowledge representation and reasoning, large-scale services, conversational systems, graphs, and more);
  • Lead the design and development of Facebook’s natural and conversational understanding platform which now processes in real-time every single post and comment;
  • Management of research & development projects and teams;
  • Co-author of the popular “REST in Practice” book;
  • Technical writer/blogger, presenter/communicator of new ideas and research work;
  • PhD and post-doctoral research in the area of software-based support for high-performance, distributed-memory, parallel architectures.

Interest keywords

Cortana, Digital Personal Assistants, Large-scale Distributed Systems, Knowledge Representation and Reasoning, Reactive Computing, Stream Processing, Big Data Processing, Cloud Computing, Graph Stores, Web Services, System Architecture, Software Design and Engineering.

Professional Experience

  • Cortana Partner Architect (May 2016 – present) – Microsoft Corporation
    Accountable for Cortana’s Core. Leading the design and implementation of the next generation interaction management engine. Responsible for the coordination of teams across the organization to ensure a consistent user experience, alignment on technologies, and a coherent architecture for the product.
  • Software Engineer (Jan 2015 – May 2016) – Facebook Corporation
    Leading efforts related to Language and Conversational Understanding and digital friends.

    • Built the Conversational Understanding (CU) and Task Completion platform for Facebook (first engineer on the project and then the Tech Lead for the team)
    • Prototype work on a “Digital Friend” experience
    • Two patents (currently going through the submission process)
      • Extensible Conversational Understanding and Task Completion platform (first author)
      • Digital Friend (an ambient intelligent experience deeply integrated into a person’s social experience) (sole author)
  • Principal Architect (Dec 2011 – present) – Microsoft Corporation
    Thought/design/architecture/execution leadership and development work on key projects: Cortana cloud-based personal digital assistant, large-scale graph store, reactive information processing at scale, conversational system. I got awarded my third “Gold Star”, which is Microsoft’s recognition for high achievement and quality of work.

    • From vision (engineer number 1) to release, I led the work on the cloud platform that powers Cortana;
    • I was responsible for the end-to-end architecture and coordination of speech recognition, language understanding, and search services for Xbox One;
    • I was awarded my third “Gold Star”, which is Microsoft’s recognition for high achievement and quality of work.
  • Principal Developer (Dec. 2009 – Dec. 2011) – Microsoft Corporation
    I worked on Big Data/Cloud Computing technologies as a developer/architect. I was responsible for the design and implementation of technologies related to large-scale distributed computation (e.g. map-reduce), NoSQL stores, and cloud services. I got awarded with my second “Gold Star” and ranked as a “top performer”.
  • Principal Developer (Dec. 2008 – 2009) – Microsoft Corporation
    I designed and prototyped Semantic search infrastructure for Bing.
  • Architect (Nov. 2006 – Nov 2008) – Microsoft Corporation
    I joined Microsoft’s Technical Computing Group, reporting to Corporate Vice President Tony Hey, in order to work on technologies, services, and tools that help scientists and researchers be more productive and efficient. I was awarded with a “Gold Star” for my work. Highlights:

    • Architected, prototyped, and lead the team that implemented Zentity, a SQL Server 2008/Entity Framework-based solution for a semantic computing platform to store and manage the research out-put of an organization; lead the team of 20 offshore engineers to execute on the implementation;
    • Technical lead of External Research’s “Cloud Computing for Science” vision, implementation, and deployment.
    • Program management of the Microsoft-Intel joined sponsorship of the Universal Parallel Computing Research Centers;
    • Design and development of various plugins for Office to be used for research (now released as open source);
    • Interactions with leading scientists worldwide;
    • Whitepapers about the future of computing for science, social networking, and semantics that reached Bill Gates who positively commented on them.
  • Program Manager (2005 – Oct. 2006) – Microsoft Corporation
    I joined Microsoft’s Connected Systems Division architecture team to investigate possible directions for the next generation development platform. While working for Brad Lovering’s team of architects, I gained valuable experience on how Microsoft technologies move from ideas and prototypes to products. I was also given the chance to own two Web Services spec-ifications and lead the necessary technical work and negotiations with IBM.
  • Principal Research Associate (2003 – 2005) – School of Computing Science, University of Newcastle
    My research while at the University of Newcastle focused in the areas of service-oriented, distributed, high-performance computing with an emphasis on Internet-scale architectures. The focal point of my investigations was the articulation of architectural principles for Internet-scale computing and how they could be applied us-ing Web Services technologies.
  • Chief Software Architect (2003 – 2005) – North-East Regional e-Science Centre (NEReSC), University of Newcastle
    In addition to being a principal research associate, I was also NEReSC’s chief software architect. NEReSC was involved in a large number of high-profile projects in the areas of data-intensive computing, bioinformatics, virtual organizations, and high-performance, distributed computing. My architectural duties included involve-ment with all the centre’s research projects during their design and architecture phases, setting the direction in terms of the set of technologies used for all implementations, and providing advice on Web and Grid stand-ards and specifications.
  • Private (2001 – 2002) – Greek army
    Fulfillment of the military service duty (awarded a distinction of honor). Although my duties in the Greek army were not related to computing science, I experienced the disciplined life of an army and learned how to work within a team.
  • Senior Software Engineer (2001) – Hewlett Packard
    Co-investigator in an R&D team in the area of Transactions for Web Services. Principal role in the research, design, and implementation of the XML Transaction Service (XTS) the prototype on which the HP-WTS 1.0 prod-uct was based.
  • Research Associate (2000 – 2001) – Dep. of Computing
    Science, University of Newcastle Post-doctoral research in the area of parallel, high-performance computing using clusters of workstations and object-oriented, visual programming languages for parallel computing.


  • Doctor of Philosophy in Computing Science (1996 – 2000) – University of Newcastle upon Tyne
    Title of PhD thesis: Run-time Support for Parallel Object-Oriented Computing.
    The research work involved the implementation of an all in software object-based DSM system, novel object caching techniques for distributed systems, and a new lazy task creation technique. The thesis dealt with de-sign and implementation issues in the areas of load-balancing, high-speed communications, and clustering.
  • Master of Science in Computing Software and Systems Design (1995 – 1996) – University of Newcastle upon Tyne
    Achieved highest marks in year. My dissertation work was in the area of run time support for mobile agents.
  • Bachelor of Science in Information Technology (1991 – 1995) – Dep. of Software Engineering, TEI of Thessaloniki, Thessaloniki, Greece
    Second in class, final year. My final-year project on DNS and sendmail was awarded with distinction.

Selected Publications

Community Participation

  • Workshop Organizer
    • Manycore Computing Workshop 07
    • Building Service Based Grids – GGF 11
    • Experiences and Future Challenges in Building Grids from
      Open Standards – UK e-Science AHM 2004
    • Service Grids: Current Activity & Middleware Requirements
    • e-Science Workflow Services
  • Journal Reviewer/Editor (sample)
    • ACM Transactions on Internet
    • IEEE Distributed Systems Online
    • International Journal of Business Process Integration and
      Management, special issue on ‘Middleware for Web Services’
    • Journal of Web Services Research, Guest Editor
    • Journal of Web Services Research, Review Board Member
  • Conference Program Committee Member (sample)
    • WWW 2006, 2007
    • Grid 2006: 7th IEEE/ACM International Conference on Grid
    • Cluster Computing and Grid 2005, 2006, 2007

Professional Memberships

  • Institute of Electrical and Electronics Engineers (IEEE),
    since 1996
  • IEEE Computer, since 1996
  • Association of Computing Machinery (ACM), since 1996