Welcome to my website!

My name is Nikolaos (“Nikos”) Papadis, and I am a 5th-year Ph.D. student in Electrical Engineering at Yale University. I am a member of the Yale Institute for Network Science (YINS) and I work under the guidance of Professor Leandros Tassiulas.

At Yale, I have got an M.Sc. and an M.Phil. in Electrical Engineering. I have also been awarded the 2019 IBM Ph.D. Fellowship.

Before coming to Yale, I did my undergraduate studies at the National Technical University of Athens (NTUA) in Greece, where I got a 5-year degree in Electrical and Computer Engineering, with specializations in Network Engineering and Computer Science. I graduated 3rd from my class (about 350 students), with a GPA of 9.50/10.

Over the summer of 2019, I was a Research Intern at IBM Research Ireland in Dublin, working on Blockchain and IoT.


The general theme of my research is building secure decentralized ecosystems for the sharing economy of the future. I am broadly interested in Blockchain, its theory and mathematical modeling and its applications, as well as in mathematical models for the sharing economy.

More specifically, issues I am interested in include:

  • the trade-offs that exist among scalability, speed, security, and decentralization of blockchain networks: how to properly model them and optimize the protocols accordingly
  • how different consensus mechanisms affect the blockchain’s performance (mathematical analysis, networking and design aspects), and what is their suitability for different applications
  • how layer-2 (off-chain) payment networks like Lightning can increase their performance and scalability while maintaining privacy

Applications include:

  • blockchain as an enabler for decentralized business entities, acting as the substrate for the interaction of distinct islands of activity connected together into a virtual organization
  • the impact blockchain can have on our lives when combined and intertwined with digital (decentralized) identity mechanisms
  • blockchain for securing Internet-of-Things networks, where devices have limited capabilities
  • data ownership and monetization: the benefits blockchain can give to ordinary users like every one of us, with regards to getting control and be the owners of our own data and avoiding privacy breaches and unauthorized data trading

I am also investigating sharing economies, through the study of mathematical models for various exchange scenarios. I am trying to identify under what conditions such exchange markets are sustainable, what equilibria they will reach, what are the optimal and incentive-compatible allocation policies for the resources in such environments, and what is the impact of the network. Different variations can exist, and applications range from infrastructure sharing and trade and organization management, to social networks and sharing economy services.

As a past work, while I was in my fifth and final year as an undergraduate at NTUA, for my thesis (which resulted later in a publication) I designed and developed a path-based algorithm for generating recommendations for online systems using data embedding in the hyperbolic space.


  • H. Niavis, N. Papadis, V. Reddy, H. Rao, L. Tassiulas, “A Blockchain-based Decentralized Data Sharing Infrastructure for Off-grid Networking”, IEEE International Conference on Blockchain and Cryptocurrency (ICBC), 2020 (link, arXiv pdf of more extensive version)
  • N. Papadis, S. Borst, A. Walid, M. Grissa, L. Tassiulas, “Stochastic Models and Wide-Area Network Measurements for Blockchain Design and Analysis”, IEEE International Conference on Computer Communications (INFOCOM), 2018 (link, pdf)
  • N. Papadis, E. Stai and V. Karyotis, “A path-based recommendations approach for online systems via hyperbolic network embedding”, 2017 IEEE Symposium on Computers and Communications (ISCC), 2017. (link, pdf)
  • N. Papadis, undergraduate thesis (in Greek, with English abstract), “Efficient recommendation algorithms for online web systems using hyperbolic network embedding”, NTUA, 2016 (link, pdf)


I can be reached by email at nikolaos.papadis “@” yale.edu (by removing the quotes).

My ResearchGate profile can be found here, and my LinkedIn profile can be found here.