Giorgos Kollias
Post Doctoral Research Associate
Computer Science Department, Purdue University
NSF/STC Center for Science of Information
Welcome to my research homepage. I hold a BSc in Physics, a MSc in Computer Science, and a PhD in Computer Engineering and Informatics. My research interests currently span the fields of graph mining, numerical linear algebra (NLA) and parallel/distributed computing.
During my PhD studies I investigated the model of parallel asynchronous iterations, experimented with graph ranking computations and built an environment for conveniently scripting, particularly parallel/distributed calculations over multicores, clusters and the Grid. In my post doctoral research, I have been working primarily on the problem of global graph alignment - which interestingly turns out to be amenable to a graph ranking approach - both as a generic technique and as a tool for the analysis of biological networks. By introducing an NLA-inspired decomposition technique we can now perform efficient and scalable graph alignments over a number of platforms including supercomputer and cloud configurations. Other aspects of my current work include the numerical exploration of perturbation, evolution, symmetry and structural information in graphs. I should also confess some enjoyable "deviations" into physics-inspired research subjects: nonlinear dynamical systems, diffusion methods in load-balancing, quantum circuits.
See my curriculum vitae for additional information.
Journal Articles (appeared or accepted)
A Fast Approach to Global Alignment of Protein-Protein Interaction Networks
G. Kollias, M. Sathe, S. Mohammadi, and A. Grama
Accepted for Publication in BMC Research Notes, 2013.
[ summary ]
Surfing the Network for Ranking by Multidamping
G. Kollias, E. Gallopoulos, and A. Grama
Accepted for Publication in IEEE Transactions on Knowledge and Data Engineering (TKDE), 2012.
[ summary ]
Universal Programmable Quantum Circuit Schemes to Emulate an Operator
A. Daskin, A. Grama, G. Kollias, and S. Kais
Accepted for Publication in Journal of Chemical Physics, 2012.
[ summary ]
Network Similarity Decomposition (NSD): A Fast and Scalable Approach to Network Alignment
G. Kollias, S. Mohammadi, and A. Grama
In IEEE Transactions on Knowledge and Data Engineering (TKDE), vol. 24, 2232--2243, 2012.
Concurrent programming constructs for parallel MPI applications
T. Berka, G. Kollias, H. Hagenauer, M. Vajteršic, and A. Grama
In The Journal of Supercomputing, 1--22, 2012.
Conference and Workshop Proceedings (refereed)
Role of synthetic genetic interactions in understanding functional interactions among pathways
S. Mohammadi, G. Kollias, and A. Grama
In Proc. Pacific Symposium On Biocomputing (PSB'12), 43--54, 2012.
A versatile system for asynchronous iterations: From multithreaded simulations to Grid experiments
G. Kollias, K. Georgiou, and E. Gallopoulos
In Parallel Computing: From Multicores and GPU's to Petascale (Proc. of ParCo 2009 Int'l Conf.), vol. 19, 238--245, 2010.
Jylab Meets Eclipse: Integrating PSEs with Multicomponent Platforms
G. Kollias, K. Georgiou, and E. Gallopoulos
In Proc. 4th IEEE Int'l. Conf. on e-Science (e-Science 2008): Innovative and Collaborative Problem Solving Environments (PSE) in Distributed Resources: PSE Workshop08, 2008.
Grid-Enabling a Problem Solving Environment: Implementation and Everyday Use
K. Georgiou, G. Kollias, and E. Gallopoulos
In Making Grids Work (Proceedings of the CoreGRID Workshop on Programming Models Grid and P2P System Architecture Grid Systems, Tools and Environments), 2008.
Asynchronous PageRank computation in an interactive multithreading environment
G. Kollias, and E. Gallopoulos
In Web Information Retrieval and Linear Algebra Algorithms (Dagstuhl Seminar Proceedings 07071), 2007.
Multidamping simulation framework for link-based ranking
G. Kollias, and E. Gallopoulos
In Web Information Retrieval and Linear Algebra Algorithms (Dagstuhl Seminar Proceedings 07071), 2007.
Jylab: A System for Portable Scientific Computing over Distributed Platforms
G. Kollias, and E. Gallopoulos
In Proc. 2nd IEEE Int'l. Conf. on e-Science and Grid Computing (e-Science 2006): Session on Innovative and Collaborative Problem Solving, 2006.
Asynchronous iterative computations with Web information retrieval structures: The PageRank case
G. Kollias, E. Gallopoulos, and D. B. Szyld
In Parallel Computing: Current and Future Issues of High-End Computing (Proc. of ParCo 2005 Int'l Conf.), vol. 33, 309--316, 2006.
Book Chapters
Asynchronous Iterative Algorithms
G. Kollias, A. Grama, and Z. Li
Article for the Encyclopedia of Parallel Computing, Springer, ISBN: 978-0-387-09765-7, 2011.
[ early preprint | bib ]
Submitted Manuscripts
Efficient Large-Scale Graph Analysis in MapReduce
K. Kambatla, G. Kollias, and A. Grama
Parallel Computing, 2012. Submitted.
[ summary ]
Fast Parallel Algorithms for Graph Similarity and Matching
G. Kollias, M. Sathe, O. Schenk, and A. Grama
Journal of Parallel and Distributed Computing, 2012. Submitted.
[ summary ]
Future Trends in Big Data Analytics
K. Kambatla, G. Kollias, V. Kumar, and A. Grama
Twenty Five Years of IPDPS Conference, 2012. Submitted
[ summary ]
Technical Reports
Fast Parallel Algorithms for Graph Similarity and Matching
G. Kollias, M. Sathe, O. Schenk, and A. Grama
CSD-TR-12-010, Purdue University, September 2012.
[ report ]
Network Similarity Decomposition (NSD): A Fast and Scalable Approach to Network Alignment
G. Kollias, S. Mohammadi, and A. Grama
CSD-TR-11-001, Purdue University, January 2011.
[ report ]
Development of pilot Grid applications for utilizing the HellasGrid infrastructure (GRID-APP project)
The development of Web page ranking applications for the Grid (in Greek)
[ report ]
Integrated approaches for the optimization of large scale networks
A critical survey of methods in computational linear algebra for the analysis of qualitative characteristics in large-scale networks (in Greek)
[ report ]
An experimental study of the proposed techniques in real world instances of large scale networks (in Greek)
Presentations and Poster Sessions
Efficient large-scale graph analysis in MapReduce
K. Kambatla, G. Kollias, and A. Grama
Presented at the Seventh International Workshop on Parallel Matrix Algorithms and Applications (PMAA'12)
in June 2012, London, UK.
Accelerating Charge Equilibration Using SPIKE Preconditioned Iterative Solvers
M. Manguoglu, G. Kollias, F. Saied, A. Sameh, and A. Grama
Presented at the poster session of the Materials Genome: Simulations, Synthesis, Characterization and Manufacturing conference
in April 2012, Ranchos Palos Verdes, California, USA.
[ poster ]
Rank Computations with Parallel Random Surfers
G. Kollias, E. Gallopoulos, and A. Grama
Presented at the SIAM Conference on Parallel Processing for Scientific Computing (SIAMPP'12)
in February 2012, Savannah, Georgia, USA.
Approximate Graph Operations on Parallel Platforms
G. Kollias, M. Sathe, O. Schenk, and A. Grama
Presented by Hasan Metin Aktulga at the SIAM Conference on Computational Science and Engineering
in March 2011, Reno, Nevada, USA.
[ slides ]
Parallel Algorithms for Graph Similarity
G. Kollias, and A. Grama
Presented at the Sixth International Workshop on Parallel Matrix Algorithms and Applications (PMAA'10)
in July 2010, Basel, Switzerland.
Asynchronous Row Projections
G. Kollias, and A. Grama
Presented at the Sixth International Workshop on Parallel Matrix Algorithms and Applications (PMAA'10)
in July 2010, Basel, Switzerland.
Properties of Google-like matrices and applications in PageRank processes
G. Kollias, and E. Gallopoulos
Presented at the Conference in Numerical Analysis (NumAn 2008)
in September 2008, Kalamata, Greece.
Design and development of Grid Ranking Tools for Web analysis
G. Kollias, E. Gallopoulos, and K. Georgiou
Presented at the 1st HellasGrid User Forum
in January 2008, Athens, Greece.
[ slides ]
Grid-enabling a Problem Solving Environment: Implementation and Everyday Use
G. Kollias, K. Georgiou, and E. Gallopoulos
Presented at the poster session of the Enabling Grids for E-sciencE Conference (EGEE'07)
in October 2007, Budapest, Hungary.
PageRank computations for compressed link-structures
E. Gallopoulos, and G. Kollias
Presented at the Joint GAMM-SIAM Conference on Applied Linear Algebra 2006 during an invited symposium on Markov Chains organized by D. B. Szyld
in July 2006, Düsseldorf, Germany.
Iterative methods for the effective computation of PageRank
G. Kollias, E. Gallopoulos, and D. B. Szyld
Presented at the 7th Hellenic European Conference on Computer Mathematics and its Applications (HERCMA 2005)
in September 2005, Athens, Greece.
Experimenting with Asynchronous Internet Computations on Clusters
G. Kollias, E. Gallopoulos, and D. B. Szyld
Presented at the Third International Workshop on Parallel Matrix Algorithms and Applications (PMAA'04)
in October 2004, Luminy, Marseille, France.
[ slides ]
Theses
Software Architectures for Problem Solving Environments and applications of the Asynchronous Computation Model
G. Kollias
PhD Thesis, Computer Engineering and Informatics Department, University of Patras, 2009 (In Greek)