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
- André Gil, “Platform architecture and data management for cloud-based buildings energy self-assessment and optimization”, Master’s thesis, Faculdade de Ciências, Universidade de Lisboa, Jan. 2022.
- Vasco Leitão, “Prioritization of Software and System Requirements through Natural Language Processing for Testing Software”, Master’s thesis, Mestrado em Ciência em Dados, Nov. 2021.
- Vinicius Vielmo Cogo, Alysson Bessani, “Brief Announcement: Auditable Register Emulations”, in 35th International Symposium on Distributed Computing (DISC 2021), Oct. 2021.
- Ricardo Mendes, Tiago Oliveira, Vinicius Vielmo Cogo, Nuno Ferreira Neves, Alysson Bessani, “CHARON: A Secure Cloud-of-Clouds System for Storing and Sharing Big Data”, IEEE Transactions on Cloud Computing, vol. 9, no. 4, pp. 1349–1361, Oct. 2021.
- Christian Berger, Hans P. Reiser, Alysson Bessani, “Making Reads in BFT State Machine Replication Fast, Linearizable, and Live”, in Proceedings of the 40th International Symposium on Reliable Distributed Systems (SRDS'21), Sept. 2021. Prof. C.V. Ramamoorthy Best Paper Award
- Miguel Moreira, “Imposição de Segurança em Aplicações Web a partir de Linguagem Intermédia”, Master’s thesis, Mestrado em Engenharia Informática, Departamento de Informática, Faculdade de Ciências da Universidade de Lisboa, Jul. 2021.
- João Caseirito, Ibéria Medeiros, “Finding Web Application Vulnerabilities with an Ensemble Fuzzing (fast abstract)”, in In Proceedings of the 51st IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'21), Jun. 2021.
- Vinicius Vielmo Cogo, João Paulo, Alysson Bessani, “GenoDedup: Similarity-Based Deduplication and Delta-Encoding for Genome Sequencing Data”, IEEE Transactions on Computers, vol. 70, no. 5, pp. 669–681, May 2021.
- Gustavo Gonzalez-Granadillo, Mario Faiella, Ibéria Medeiros, Rui Azevedo, Susana Gonzalez-Zarzosa, “ETIP: An Enriched Threat Intelligence Platform for Improving OSINT Correlation, Analysis, Visualisation and Sharing Capabilities”, Journal of Information Security and Applications, Elsevier, vol. 58, May 2021.
- Vasco Leitão, Ibéria Medeiros, “SRXCRM: Discovering Association Rules Between System Requirements and Product Specifications”, in In Proceedings of the International Workshop on Natural Language Processing for Requirements Engineering (NLP4RE), Apr. 2021.
Friday, 2015-Feb-12, 11h30-12h00, 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
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.
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 jobcompletion time.