My research interests include distributed computing, object-oriented distributed programming, fault-tolerance, peer-to-peer and gossip protocols. My main goal is to develop protocols and systems that survive: to failures, to dynamism, to adversarial environments. During my Ph.D. years, and slightly after, my interest was on reliable group communication systems; in these days, I’m exploring the potentiality of gossip protocols in large-scale, dynamic distributed systems.

1.1 Intelligent gossip

When you have a hammer, everything looks like a nail. I have a ”gossip” hammer: every problem looks solvable through a gossip protocol. Clearly this is not true, but it is interesting to see how many problems can be solved with the same algorithmic scheme. So far:

A summary of the potentiality of this approach can be found in [27]; interdisciplinary aspects of gossip are discussed in [34].

1.2 Decentralized Online Social Networks

Online social networks (OSN) have attracted millions of users. This enormous success is not without problems; the centralized architectures of OSNs, storing the users’ personal data, provides ample opportunity to privacy violation. These problems have raised the demand for open, decentralized alternatives. We tackle the research question: is it possible to build a decentralized OSN over a social overlay, i.e., an overlay network whose links among nodes mirror the social network relationships among the nodes’ owners? Giuliano Mega, Gian Pietro Picco and myself started a preliminary study to understand whether one fundamental piece of OSN (dissemination of profile updates) can be implemented in a decentralized way [6]. The first results are encouraging.

1.3 Distributed Analysis of Large-Scale Graphs

The real world is full of graphs. There are graphs hidden in the friendship relationships between people, in economic transactions, between strangers encountering each other in the streets, in the way gossip spreads through the people, and so on. Few years ago we know they were there, but we were not able to analyze them because the lack of data. Nowadays, however, most of the human activities are mediated by some electronic device, so large datasets describing these graphs have started to become available.

Analyzing these datasets could be difficult. Sometimes they are too large, sometimes they are distributed by nature. I’ve recently started studying distributed approaches to such analysis, together with Francesco De Pellegrini and Daniele Miorandi. We studied the problem of the distributed computation of k-core decomposition [7].

1.4 The clash of the buzzword titans: P2P vs Cloud

Peer-to-peer (P2P) and cloud computing, two of the Internet trends of the last decade, hold similar promises: the (virtually) infinite availability of computing and storage resources. But there are important differences: the cloud provides highly-available resources, but at a cost; P2P resources are for free, but their availability is affected by churn. Together with Luca Abeni, we are investing a novel novel approach for the construction of dependable applications, using the cloud to provide highly-available and durable services, while exploiting “free” P2P resources when available. The novelty of our idea stems from the clever combination of the gossip paradigm with a storage cloud, that allows to keep the monetary cost of the cloud always under control, in the presence of just one peer or with a million of them. These ideas have been presented in Kyoto during P2P’11 [5]. Further results will be published in IWSOS’12 [4].

1.5 Distributed optimization

Scientists working in the area of distributed function optimization have to deal with a huge variety of optimization techniques and algorithms. Most of the existing research in this domain make use of tightly-coupled systems that either have strict synchronization requirements or completely rely on a central server, which coordinates the work of clients and acts as a state repository. The possibility of performing such optimization tasks in a P2P decentralized network of solvers has been investigated and explored, obtaining quite promising results. Marco Biazzini, a former Ph.D. student of mine, designed and developed GOOF, a ‘GOssiping Optimization Framework’ that aims to bridge the gap between the issues related to the design and deployment of large-scale P2P systems and the need to easily deploy and execute optimization tasks in such a distributed environment.

1.6 Autonomic security

I’ve recently started at looking at the security implications of large-scale, decentralized, open distributed systems. This effort is part of an Italian-funded project called Autonomic Security. So far, we have dealt with the following subjects:

1.7 Replicability vs Reproducibility

Most of my recent work is in the field of experimental computer science. My collaborators and myself build real or simulated protocols; while we always try to analytically prove interesting properties about them (see the upper bounds on execution time in [7]), the bulk of the evaluation is done through extended experimentation.

Experimental computer science could be compared with experimental physics; we both build systems and then test their (physical or logical) properties. But there is a difference: an important component of physics is the repetition of experiments, which is almost completely absent in computer science. I’m not the only one to worry about this problem:

By skimming through this literature, a general lesson can be learned: while Drummond argues that releasing the code is not enough (and could be even dangerous for good science), I do believe that providing as much information as possible (code, config files, libraries, etc) is a good thing. This approach provides only replicability, and does not incentivize other researchers to reproduce your work; however, it is a first and important step to have a much healthy scientific approach. Furthermore, given the limited number of pages available in conference publications, and given the complexity of modern software artifacts, releasing the source code and the configuration files is an important way to provide the missing details.

As an example of the good practice that can derive from this approach, have a look at this email exchange that I had with Jan Sacha, about a bug he found first in my paper about superpeer topology construction and then in the code [50]. The modified code, kindly provided by Jan, can be found here . I do believe that this would have not been possible without the publication of the original code.

In the following table, I will try to provide the code for my papers; unfortunately, I don’t have the code for all of them - so even I am not able to reproduce my results...

1.8 Former projects

A short description of the previous projects I’ve participated in, together with selected bibliography for some of them, are provided at following links.

References

[1] Marco Biazzini and Alberto Montresor. P2POEM: Function optimization in p2p networks. Peer-to-Peer Networking and Application, 2012. To appear. [PDF], [Bibtex].

[2] Alberto Montresor. Designing extreme distributed systems: Challenges and opportunities (extended abstract). Proc. of the Federated Events on Component-Based Software Engineering and Software Architecture (Comparch’12), Bertinoro, Italy, June 2012. To appear. [PDF], [Bibtex] .

[3] Alberto Montresor, Francesco de Pellegrini, and Daniele Miorandi. Distributed k-core decomposition. IEEE Trans. on Parallel and Distributed Systems, 2012. To appear. [PDF], [Bibtex].

[4] Hanna Kavalionak and Alberto Montresor. P2P and cloud: A marriage of convenience for replica management. In Proc. of the 7th IFIP Int. Workshop on Self-Organizing Systems (IWSOS’12), number 7166 in Lecture Notes in Computer Science, pages 60–71. Springer, Delft, The Netherlands, March 2012. To appear. [PDF], [Bibtex].

[5] Alberto Montresor and Luca Abeni. Cloudy weather for p2p, with a chance of gossip. In Proc. of the 11th IEEE P2P Conference on Peer-to-Peer Computing (P2P’11), pages 250–259. IEEE, August 2011. Best paper award. [PDF], [Bibtex].

[6] Giuliano Mega, Alberto Montresor, and Gian Pietro Picco. Efficient dissemination in decentralized social networks. In Proc. of the 11th IEEE P2P Conference on Peer-to-Peer Computing (P2P’11), pages 338–347. IEEE, August 2011. [PDF], [Bibtex].

[7] Alberto Montresor, Francesco de Pellegrini, and Daniele Miorandi. Brief announcement: Distributed k-core decomposition. In Proc. of the 30th Annual ACM SIGACT-SIGOPS Symposium on Principles of Distributed Computing (PODC’11), pages 207–208. ACM, June 2011. Full version available here . [PDF], [Bibtex].

[8] Gabriela Gheorghe, Renato Lo Cigno, and Alberto Montresor. Security and privacy issues in P2P streaming systems: A survey. Peer-to-Peer Networking and Application, 4(2):75–91, 2011. [PDF], [Bibtex].

[9] Pascal Felber, Olivier Beaumont, Alberto Montresor, and Amitabha Bagchi. Topic 7 - Peer-to-Peer Computing. In Euro-Par, volume 6852 of Lecture Notes in Computer Science, pages 514–515. Springer, Bordeaux, France, August 2011. [Bibtex].

[10] Alan Bertossi and Alberto Montresor. Algoritmi e strutture di dati. Cittá Studi Edizioni, Torino, 2010. [Bibtex].

[11] Marco Biazzini and Alberto Montresor. Gossiping differential evolution: a decentralized heuristic for function optimization in p2p networks. In Proc. of the 16th Int. Conference on Parallel and Distributed Systems (ICPADS’10). IEEE, December 2010. [PDF], [Bibtex].

[12] Marco Ajelli, Renato Lo Cigno, and Alberto Montresor. Modeling botnets and epidemic malware. In Proc. of the Int. Communications Conference (ICC’10). IEEE, May 2010. [PDF], [Bibtex].

[13] Gian Paolo Jesi, Alberto Montresor, and Maarten van Steen. Secure peer sampling. Computer Networks, 54(13):2086–2098, June 2010. [PDF] , [Bibtex].

[14] Alessio Guerrieri, Iacopo Carreras, Francesco De Pellegrini, Daniele Miorandi, and Alberto Montresor. Distributed estimation of global parameters in delay–tolerant networks. Computer Communications, 33(13): 1472–1482, August 2010. [PDF], [Bibtex].

[15] Luca Abeni and Alberto Montresor. Scheduling in p2p streaming: From algorithms to protocols. In Thrasyvoulos Spyropoulos and Karin Anna Hummel, editors, Proc. of the 4th IFIP Int. Workshop on Self-Organizing Systems (IWSOS’09), volume 5918 of Lecture Notes in Computer Science, pages 201–206. Springer, Zurich, Switzerland, December 2009. ISBN 978-3-642-10864-8. [PDF], [Bibtex].

[16] Alberto Montresor and Márk Jelasity. Peersim: A scalable p2p simulator. In Proc. of the 9th Int. Conference on Peer-to-Peer (P2P’09), pages 99–100. IEEE, Seattle, WA, September 2009. [PDF], [Bibtex].

[17] Alberto Montresor, Fabrice Saffre, and Nenad Medvidovic, editors. 3rd IEEE Int. Conference on Self-Adaptive and Self-Organizing Systems (SASO’09). IEEE, San Francisco, CA, September 2009. [Bibtex].

[18] Alberto Montresor and Ali Ghodsi. Towards robust peer counting. In Proc. of the 9th Int. Conference on Peer-to-Peer (P2P’09), pages 143–146. IEEE, Seattle, WA, September 2009. [PDF], [Bibtex].

[19] Marco Biazzini, Balázs Bánhelyi, Alberto Montresor, and Márk Jelasity. Distributed hyper-heuristics for real parameter optimization. In Proc. of the 11th Genetic and Evolutionary Computation Conference (GECCO’09), pages 1339–1346. ACM, Montreal, Québec, Canada, July 2009. ISBN 978-1-60558-325-9. [PDF], [Bibtex].

[20] Gian Paolo Jesi and Alberto Montresor. Secure peer sampling service: the mosquito attack. In Proc. of the 5th WETICE Workshop on Collaborative Peer-to-Peer Systems (COPS’09). IEEE, Groningen, The Netherlands, July 2009. [PDF], [Bibtex].

[21] Hein Meling and Alberto Montresor. Type-safe dynamic protocol composition in jgroup/arm. In Proc. of the 3rd Int. DiscCoTec Workshop on Middleware-Application Interaction (MAI’09), pages 1–6. ACM, New York, NY, USA, June 2009. ISBN 978-1-60558-489-8. [Bibtex].

[22] Alessio Guerrieri, Alberto Montresor, Iacopo Carreras, Francesco De Pellegrini, and Daniele Miorandi. Distributed estimation of global parameters in delay–tolerant networks. In Proc. of the 3rd IEEE WoWMoM Workshop on Autonomic and Opportunistic Communications (AOC’09). IEEE, Kos, Greece, June 2009. [PDF], [Bibtex].

[23] Balázs Bánhelyi, Marco Biazzini, Alberto Montresor, and Márk Jelasity. Peer-to-peer optimization in large unreliable networks with branch-and-bound and particle swarms. In Applications of Evolutionary Computing, Lecture Notes in Computer Science, pages 87–92. Springer, jul 2009. An extended version of the paper can be found here . [PDF], [Bibtex].

[24] Márk Jelasity, Alberto Montresor, and Ozalp Babaoglu. T-Man: Gossip-based fast overlay topology construction. Computer Networks, 53 (13):2321–2339, 2009. [PDF], [Bibtex].

[25] Mark Little, Alberto Montresor, and Greg Pavlik, editors. Proc. of the 10th Int. Symposium on Distributed Objects, Middleware, and Applications (DOA’08), volume 5331 of Lecture Notes in Computer Science. Springer, Monterrey, Mexico, November 2008. [Bibtex].

[26] Alberto Montresor, Márk Jelasity, and Ozalp Babaoglu. Decentralized ranking in large-scale overlay networks. In Proc. of the 1st IEEE Selfman SASO Workshop, pages 208–213. IEEE, Isola di San Servolo, Venice, Italy, November 2008. An extended version of the paper can be found here . [PDF], [Bibtex].

[27] Alberto Montresor. Intelligent gossip. In 2nd Int. Symposium on Intelligent Distributed Computing (IDC’08). Springer, Catania, Italy, September 2008. Invited paper. [PDF], [Bibtex].

[28] Dick H. J. Epema, Alberto Montresor, Márk Jelasity, and Josep Jorba. Topic 7 - Peer-to-Peer Computing. In Euro-Par, volume 5168 of Lecture Notes in Computer Science, pages 599–600. Springer, Las Palmas de Gran Canaria (Spain), August 2008. [Bibtex].

[29] Hein Meling, Alberto Montresor, Bjarne Helvik, and Ozalp Babaoglu. Jgroup/ARM: A distributed object group platform with autonomous replication management. Software Prac. Exper., 38(9):885–923, July 2008. [PDF], [Bibtex].

[30] Alberto Montresor. Decentralized network analysis: a proposal. In 4th WETICE Workshop on Collaborative Peer-to-Peer Systems (COPS’08). IEEE, Rome, Italy, June 2008. Invited paper. [PDF], [Bibtex].

[31] Marco Biazzini, Alberto Montresor, and Mauro Brunato. Towards a decentralized architecture for optimization. In Proc. of the 22nd IEEE Int. Parallel and Distributed Processing Symposium (IPDPS’08). IEEE, Miami, FL, USA, April 2008. [PDF], [Bibtex].

[32] Alberto Montresor and Roberto Zandonati. Absolute slicing in peer-to-peer systems. In Proc. of the 5th Int. Workshop on Hot Topics in Peer-to-Peer Systems (HotP2P’08). IEEE, Miami, FL, USA, April 2008. [PDF], [Bibtex].

[33] Gian Paolo Jesi, Alberto Montresor, and Ozalp Babaoglu. Proximity-aware superpeer overlay topologies. IEEE Transactions on Network and Service Management, 4(2):74–83, September 2007. [PDF], [Bibtex].

[34] Paolo Costa, Vincent Gramoli, Márk Jelasity, Gian Paolo Jesi, Erwan Le Merrer, Alberto Montresor, and Leonardo Querzoni. Exploring the interdisciplinary connections of gossip-based systems. SIGOPS Oper. Syst. Rev., 41(5):51–60, October 2007. ISSN 0163-5980. [PDF], [Bibtex] .

[35] Manfred Hauswirth, Adam Wierzbicki, Klaus Wherle, Alberto Montresor, and Nahid Shahmehri, editors. Proc. of the 7th Int. Conference on Peer-to-Peer Computing (P2P’07). IEEE, September 2007. [PDF], [Bibtex].

[36] Alberto Montresor, Fabrice Le Fessant, Dick H. J. Epema, and Spyros Voulgaris. Topic 7 - Peer-to-Peer Computing. In Euro-Par, volume 4641 of Lecture Notes in Computer Science, pages 477–478. Springer, August 2007. [Bibtex].

[37] Ozalp Babaoglu, Toni Binci, Márk Jelasity, and Alberto Montresor. Firefly-inspired heartbeat synchronization in overlay networks. In Proc. of the First IEEE Int. Conference on Self-Adaptive and Self-Organizing Systems (SASO’07). IEEE, Boston, MA, USA, July 2007. [PDF], [Bibtex] .

[38] Alberto Montresor, Adam Wierzbicki, and Nahid Shahmehri, editors. Proc. of the 6th Int. Conference on Peer-to-Peer Computing (P2P’06). IEEE, September 2006. [PDF], [Bibtex].

[39] Ozalp Babaoglu, Geoffrey Canright, Andreas Deutsch, Gianni Di Caro, Frederick Ducatelle, Luca Gambardella, Niloy Ganguly, Márk Jelasity, Roberto Montemanni, and Alberto Montresor. Design patterns from biology for distributed computing. ACM Transactions on Autonomous and Adaptive Systems, 1(1):26–66, September 2006. [PDF], [Bibtex].

[40] Márk Jelasity, Alberto Montresor, and Ozalp Babaoglu. The bootstrapping service. In Proc. of Int. ICDCS Workshop on Dynamic Distributed Systems (ICDCS-IWDDS’06). IEEE Computer Society, Lisboa, Portugal, July 2006. [PDF], [Bibtex].

[41] Anurag Garg, Alberto Montresor, and Roberto Battiti. Reputation lending for virtual communities. In Roger S. Barga and Xiaofang Zhou, editors, Proc. of the 22nd Int. Conference on Data Engineering Workshops (ICDE’06), pages 22–31. IEEE Computer Society, Atlanta, GA, USA, April 2006. [PDF], [Bibtex].

[42] Gian Paolo Jesi, Alberto Montresor, and Ozalp Babaoglu. Proximity-aware superpeer overlay topologies. In Proc. of SelfMan’06, volume 3996 of Lecture Notes in Computer Science, pages 43–57. Springer-Verlag, Dublin, Ireland, June 2006. Best paper award. [PDF], [Bibtex].

[43] Frank Eliassen and Alberto Montresor, editors. Distributed Applications and Interoperable Systems: 6th IFIP WG 6.1 Int. Conference, DAIS’06, volume 4025 of Lecture Notes in Computer Science. Springer-Verlag, June 2006. ISBN 3-540-35126-4. [Bibtex].

[44] Ozalp Babaoglu, Márk Jelasity, Anne-Marie Kermarrec, Alberto Montresor, and Maarten van Steen. Managing clouds: A case for a fresh look at large unreliable dynamic networks. SIGOPS Oper. Syst. Rev., 40 (3):9–13, July 2006. [PDF], [Bibtex].

[45] Ozalp Babaoglu, Geoffrey Canright, Andreas Deutsch, Gianni Di Caro, Frederick Ducatelle, Luca Gambardella, Niloy Ganguly, Márk Jelasity, Roberto Montemanni, and Alberto Montresor. Design patterns from biology for distributed computing. In Proc. of the European Conference on Complex Systems. Paris, France, November 2005. [PDF], [Bibtex].

[46] Alberto Montresor, Márk Jelasity, and Ozalp Babaoglu. Chord on demand. In Proc. of the 5th Int. Conference on Peer-to-Peer Computing (P2P’05), pages 87–94. IEEE, Konstanz, Germany, August 2005. [PDF], [Bibtex].

[47] Márk Jelasity, Alberto Montresor, and Ozalp Babaoglu. Gossip-based aggregation in large dynamic networks. ACM Trans. Comput. Syst., 23(1): 219–252, August 2005. [PDF], [Bibtex].

[48] Ozalp Babaoglu, Márk Jelasity, Alberto Montresor, Christof Fetzer, Stefano Leonardi, Aad van Moorsel, and Maarten van Steen, editors. Self-Star Properties in Complex Information Systems, volume 3460 of Lecture Notes in Computer Science, Hot Topics. Springer-Verlag, May 2005. ISBN 3-540-26009-9. [Bibtex].

[49] Bjarne Helvik, Hein Meling, and Alberto Montresor. An approach to experimentally obtain service dependability characteristics of the Jgroup/ARM system. In Proc. of the 5th European Dependable Computing Conference (EDCC’05). Springer, Budapest, Hungary, April 2005. [PDF] , [Bibtex].

[50] Alberto Montresor. A robust protocol for building superpeer overlay topologies. In Proc. of the 4th Int. Conference on Peer-to-Peer Computing, pages 202–209. IEEE, Zurich, Switzerland, August 2004. [PDF], [Bibtex] .

[51] Alberto Montresor, Márk Jelasity, and Ozalp Babaoglu. Robust aggregation protocols for large-scale overlay networks. In Proc. of the 2004 Int. Conference on Dependable Systems and Networks (DSN’04), pages 19–28. IEEE Computer Society, Florence, Italy, June 2004. [PDF], [Bibtex].

[52] Márk Jelasity, Alberto Montresor, and Ozalp Babaoglu. A modular paradigm for building self-organizing peer-to-peer applications. In Engineering Self-Organising Systems: Nature-Inspired Approaches to Software Engineering, number 2977 in Lecture Notes in Artificial Intelligence, pages 265–282. Springer-Verlag, April 2004. [PDF], [Bibtex] .

[53] Márk Jelasity and Alberto Montresor. Epidemic-style proactive aggregation in large overlay networks. In Proc. of the 24th Int. Conference on Distributed Computing Systems (ICDCS’04), pages 102–109. IEEE Computer Society, Tokyo, Japan, March 2004. [PDF], [Bibtex].

[54] Nadia Busi, Alberto Montresor, and Gianluigi Zavattaro. Data-driven coordination in peer-to-peer information systems. Int. Journal of Cooperative Information Systems, 13(1):63–89, March 2004. [PDF], [Bibtex].

[55] Alberto Montresor, Hein Meling, and Ozalp Baboglu. Messor: Load-balancing through a swarm of autonomous agents. In Procc. of the 1st Workshop on Agent and Peer-to-Peer Systems (AP2PC’02), number 2530 in Lecture Notes in Artificial Intelligence, pages 125–137. Springer-Verlag, Bologna, Italy, July 2003. [PDF], [Bibtex].

[56] Nadia Busi, Cristian Manfredini, Alberto Montresor, and Gianluigi Zavattaro. PeerSpaces: Data-driven coordination in peer-to-peer networks. In Proc. of the 18th Symposium on Applied Computing (SAC’03), pages 380–386. ACM, Melbourne, Florida, March 2003. [PDF], [Bibtex].

[57] Alberto Bartoli, Cosimo Calabrese, Milan Prica, Etienne Antoniutti Di Muro, and Alberto Montresor. Adaptive message packing for group communication systems. In Proc. of the Workshop on Reliable and Secure Middleware (WRSM’03), number 2889 in Lecture Notes in Computer Science, pages 912–925. Springer-Verlag, 2003. [PDF], [Bibtex].

[58] Alberto Montresor, Hein Meling, and Ozalp Babaoglu. Towards adaptive, resilient and self-organizing peer-to-peer systems. In Web Engineering and Peer-to-Peer, number 2376 in Lecture Notes in Computer Science, pages 300–305. Springer-Verlag, 2002. [PDF], [Bibtex].

[59] Nadia Busi, Cristian Manfredini, Alberto Montresor, and Gianluigi Zavattaro. Towards a Data-Driven Coordination Infrastructure for Peer-to-Peer Systems. In Web Engineering and Peer-to-Peer, number 2376 in Lecture Notes in Computer Science, pages 295–299. Springer-Verlag, 2002. [PDF], [Bibtex].

[60] Ozalp Babaoglu, Hein Meling, and Alberto Montresor. Anthill: A framework for the development of agent-based peer-to-peer systems. In Proc. of the 22th Int. Conference on Distributed Computing Systems (ICDCS’02). IEEE, Vienna, Austria, July 2002. [PDF], [Bibtex].

[61] Ozalp Babaoglu, Renzo Davoli, and Alberto Montresor. Group communication in partitionable systems: Specification and algorithms. IEEE Transactions on Software Engineering, 27(4):308–336, April 2001. [PDF], [Bibtex].

[62] Ozalp Babaoglu, Renzo Davoli, and Alberto Montresor. Group communication in partitionable systems: Specification and algorithms. In Sacha Krakoviak and Santosh Shirivastava, editors, Advances in Distributed Systems, number 1752 in Lecture Notes in Computer Science, pages 48–78. Springer-Verlag, 2000. [PDF], [Bibtex].

[63] Alberto Montresor. The jgroup reliable distributed object model. In Proc. of the 2nd IFIP Int. Working Conference on Distributed Applications and Interoperable Systems (DAIS’99), pages 389–402. Kluwer, Helsinki, Finland, June 1999. [PDF], [Bibtex].

[64] Ozalp Babaoglu, Renzo Davoli, Alberto Montresor, and Roberto Segala. System support for partition-aware network applications. In Proc. of the 18th Int. Conference on Distributed Computing Systems (ICDCS’98), pages 184–191. IEEE, Amsterdam, The Netherlands, May 1998. [PDF], [Bibtex] .

Alberto Montresor

Associate Professor

1 Research Interests