Vaggos (Evangelos) Chatziafratis
firstname.lastname@example.org where first = vaggos
I am a 4th year PhD student in the Computer Science Department at Stanford University.
I am working on approximation algorithms, combinatorial optimization and machine learning theory. Starting Spring 2019, I will be spending some of my time in Columbia University, NYC.
I am thrilled to be advised by Tim Roughgarden and to be part of our wonderful Theory Group. During my time at Stanford, I also had the privilege to work closely with Moses Charikar, Rad Niazadeh and Jan Vondrák.
Prior to Stanford, I received my Diploma in EECS from the National Technical University of Athens, Greece.
- 15 - 22 April'19: AISTATS and visit to Tokyo Institute of Technology to present our paper to their AI & Web Mining lab.
- 29 March'19: Excited to present our work at Columbia's Theory Seminar.
- 21 February - 7 March'19: Visiting Ioannis Panageas at Singapore University of Technology and Design. On the 27th, I will be presenting an overview of recent results on Hierarchical Clustering.
- 19 February'19: Talk on Hierarchical Clustering in Facebook's Computer Vision group, Menlo Park.
- 14&20 February'19: Talk on the Computational Power of Online Gradient Descent in Stanford's Theory and ML groups.
- Excited to join Google New York for an internship next summer under Mohammad Mahdian and Vahab Mirrokni.
- 12&13 December'18: Talk on Hierarchical Clustering at Google Zurich and ETH Zurich algorithms seminar.
- On the Computational Power of Online Gradient Descent.
Vaggos Chatziafratis, Tim Roughgarden, Joshua R. Wang.
- On Correlation Clustering with Fairness Objectives.
Vaggos Chatziafratis, Neha Gupta.
work in progress.
- Bilu-Linial stability, certified algorithms and the Independent Set problem.
Haris Angelidakis, Pranjal Awasthi, Avrim Blum, Vaggos Chatziafratis, Chen Dan.
- Hierarchical Clustering for Euclidean Data.
Moses Charikar, Vaggos Chatziafratis, Rad Niazadeh, Grigory Yaroslavtsev.
22nd International Conference on Artificial Intelligence and Statistics, (AISTATS 2019), Naha, Okinawa (Japan), April 2019.
- Hierarchical Clustering better than Average-Linkage.
Moses Charikar, Vaggos Chatziafratis, Rad Niazadeh.
30th ACM-SIAM Symposium on Discrete Algorithms (SODA 2019), San Diego (CA), January 2019.
- Hierarchical Clustering with Structural Constraints.
Vaggos Chatziafratis, Rad Niazadeh, Moses Charikar.
35th International Conference on Machine Learning (ICML 2018), Stockholm (Sweden), July 2018. [10min ICML Video]
- Attack vulnerability of power systems under an
equal load redistribution model.
Talha Cihad Gulcu, Vaggos Chatziafratis, Yingrui Zhang, and Osman Yağan.
IEEE/ACM Transactions on Networking (ToN 2018), 26(3): 1306-1319, June 2018. (Journal).
- Stability and Recovery for Independence Systems.
Vaggos Chatziafratis, Tim Roughgarden, Jan Vondrák.
25th European Symposium on Algorithms (ESA 2017), Vienna (Austria), September 2017.
- Approximate Hierarchical Clustering via Sparsest Cut and Spreading Metrics.
Moses Charikar, Vaggos Chatziafratis.
28th ACM-SIAM Symposium on Discrete Algorithms (SODA 2017), Barcelona (Spain), January 2017.
- On the robustness of power systems: optimal
load-capacity distributions and hardness of attacking.
Vaggos Chatziafratis, Yingrui Zhang, Osman Yağan.
11th Information Theory and Applications Workshop (ITA 2016), San Diego (CA), February 2016. (Invited).
- Summer 2018: Facebook Internship in Core Data Science under Julian Mestre and Nicolas Stier.
- Summer 2017: Research Assistant at Stanford University under Greg Valiant.
- Summer 2016: Research Internship at École Polytechnique Federal de Lausanne (EPFL), Switzerland.
- Summer 2015: Software Engineering Internship at CERN in Switzerland.
- Winter 2014: Software Engineering Internship at Lappeenranta University of Technology, Finland.
- Leadership at Stanford:
- President of HELLAS (Hellenic Association at Stanford): Organizing Stanford-wide cultural events.
- Stanford GSPB (Graduate Student Programming Board): Organizing social events for the grad community.
- Music: Diploma in Classical Piano and Music Theory, Greece. Student of Kumaran Arul at Stanford's Music Department.
- Theater: Playback Theater under Omer Reingold.
- Mentoring Greek students through Global Prep by raising awareness and providing information about grad school in the US.
- Organizing annual Educational Trip with the collaboration of MIT, Princeton, UC Berkeley, UC San Diego, Georgia Tech.
- National Hellenic Student Association: NHSA's Executive Board Member.