We are the Navigators, a research team on distributed systems, their architectures, their algorithms, in their several skins: fault tolerance, real-time, security, and combinations thereof.
We also pursue the quest for the right balance between science and technology. Some people say that Informatics (a.k.a. computer science and engineering) belongs to a new breed, of what are called techno-sciences. We believe that techno-scientists should accompany theoretical mastery with a deep knowledge of their environment — computer technology — as well as astro-physicists know the sky, or marine biologists know the sea.
We study new theories to explain distributed systems, and new algorithms to take advantage from them. But we also like to do proof-of-concept experiments about the theory we work on. We try that our papers and theses tell a good story as clearly as possible. We work hard for our demonstrations to be convincing and captivating. Because we believe science is made for others.
- (1/Feb/2015) A new European project has started, called SUPERCLOUD - User-Centric Management of Security and Dependability in Cloud of Clouds
- (1/Oct/2014) A new European project has started, called SEGRID - Security for smart Electricity GRIDs
- Diego Kreutz, Alysson Bessani, Eduardo Feitosa, Hugo Cunha, “Towards Secure and Dependable Authentication and Authorization Infrastructures”, in 20th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC), Singapore, Nov. 2014.
- Eric Vial, António Casimiro, “Evaluation of Safety Rules in a Safety Kernel-Based Architecture”, in Workshop on Architecting Safety in Collaborative Mobile Systems (ASCoMS'14), SAFECOMP 2014 Workshops, A. Bondavalli et al., Eds., ser. LNCS. Florence, Italy: Springer International Publishing, Sept. 2014, pp. 27–35.
- Fabio Botelho, Alysson Bessani, Fernando Ramos, Paulo Ferreira, “On the Design of Practical Fault-Tolerant SDN Controllers”, in Third European Workshop on Software Defined Networks (EWSDN 2014), Sept. 2014.
- Fernando Alves, Vinicius Vielmo Cogo, Alysson Bessani, “Indexação sob Demanda para a Compressão Referencial de Ficheiros de ADN”, in Proceedings of the 6th Simpósio de Informática (INFORUM 2014), Salvador Pinto Abreu, João Pascoal Faria, Eds., Porto, Portugal, Sept. 2014, pp. 5–16.
- Gonçalo Jesus, Anabela Oliveira, António Casimiro, “Ensuring reliable measurements in remote aquatic sensor networks”, in Proceedings of the 11th International Conference on Hydroinformatics, New York City, USA, Aug. 2014.
- Tiago Oliveira, Ricardo Mendes, Alysson Bessani, “Sharing Files Using Cloud Storage Services”, in Second Workshop on Dependability and Interoperability in Heterogeneous Clouds (DIHC 2014), co-alocated with Euro-Par, Aug. 2014.
- Ricardo Correia Pinto, José Rufino, “Towards Non-invasive Run-time Verification of Real-Time Systems”, in Work-in-Progress Session of the 26th Euromicro Conference on Real-Time Systems (ECRTS), Madrid, Spain, Jul. 2014, pp. 25–28.
- Jeferson L. R. Souza, José Rufino, “Low Level Error Detection For Real-Time Wireless Communications”, in 13th International Workshop on Real-Time Networks (RTN) - In Conjunction with 26th Euromicro International Conference on Real-Time Systems (ECRTS), Madrid, Spain, Jul. 2014.
- Filipe Araujo, Serhiy Boychenko, Raul Barbosa, António Casimiro, “Replica placement to mitigate attacks on clouds”, Journal of Internet Services and Applications, vol. 5, no. 1, Jul. 2014.
- António Casimiro, Oscar Morales-Ponce, Thomas Petig, Elad M. Schiller, “Vehicular Coordination via a Safety Kernel in the Gulliver Test-bed (Invited Paper)”, in The Thirteenth International Workshop on Assurance in Distributed Systems and Networks (ADSN 2014), Proceedings of the 34th International Conference on Distributed Computing Systems Workshops, Madrid, Spain, Jun. 2014.
Friday, 2015-Mar-13, 12h15-14h00, room C6.3.38
Title: Projeto de rede WAN – estudo de caso: rede do Exército Brasileiro
Abstract: O estudo de caso a ser apresentado se trata de uma parte da Rede de Longa Distância (Wide Area Network - WAN) do Exército Brasileiro, na qual caracteriza-se por ser, em cada Ponto de Presença instalado em Organização Militar específica, um pacote de serviços de dados, voz e vídeo, por meio de uma rede IP multisserviços, em MPLS, de abrangência nacional, para o tráfego de informações corporativas
In this navtalk, I will present an Hadoop proxy that allows MapReduce computation to scale out to multiple clouds and to tolerate cloud faults. Our solution addresses three challenges. First, it does not require any modification to the Hadoop framework. Second,the proposed system tolerates arbitrary and malicious faults, as well as cloud outages. Third, it achieves cloud fault tolerance at reasonable cost by guaranteeing minimum replication and scheduling replicated jobs to clouds that minimize the expected job completion time.
Title: An Efficient MapReduce Middleware to Tolerate Cloud Faults
Abstract: Applications such as web search and social networking have been moving from centralized to decentralized cloud architectures to improve their scalability. MapReduce, a programming framework for processing large amounts of data using thousands of machines in a single cloud, also needs to be scaled out in multiple distributed clouds to adapt to this architecture evolution.