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Displaying 1-39 out of 39 total
A New Programming Model for Dependable Adaptive Real-Time Applications
Found in: IEEE Distributed Systems Online
By Pedro Martins, Paulo Sousa, António Casimiro, Paulo Veríssimo
Issue Date:May 2005
pp. 1
The CORTEX (Cooperating Real-time Sentient Objects: Architecture and Experimental Evaluation) project focuses on developing dependable real-time applications in environments of uncertain synchrony. Developed in the context of the CORTEX project, this innov...
 
RAVE: Replicated antivirus engine
Found in: Dependable Systems and Networks Workshops
By Carlos Silva, Paulo Sousa, Paulo Verissimo
Issue Date:July 2010
pp. 170-175
Antivirus is a fundamental presence in every computer infrastructure nowadays. The exponential growth of Internet usage with increasing higher bandwidth led to situations where virus (as well as worms and other type of malicious content) had constant outbr...
 
Highly Available Intrusion-Tolerant Services with Proactive-Reactive Recovery
Found in: IEEE Transactions on Parallel and Distributed Systems
By Paulo Sousa, Alysson Neves Bessani, Miguel Correia, Nuno Ferreira Neves, Paulo Verissimo
Issue Date:April 2010
pp. 452-465
In the past, some research has been done on how to use proactive recovery to build intrusion-tolerant replicated systems that are resilient to any number of faults, as long as recoveries are faster than an upper bound on fault production assumed at system ...
 
The Crutial Way of Critical Infrastructure Protection
Found in: IEEE Security and Privacy
By Alysson Neves Bessani, Paulo Sousa, Miguel Correia, Nuno Ferreira Neves, Paulo Veríssimo
Issue Date:November 2008
pp. 44-51
Critical infrastructures such as the power grid are essentially physical processes controlled by computers connected by networks. They're usually as vulnerable as any other interconnected computer system, but their failure has a high socioeconomic impact. ...
 
Resilient Intrusion Tolerance through Proactive and Reactive Recovery
Found in: Pacific Rim International Symposium on Dependable Computing, IEEE
By Paulo Sousa, Alysson Neves Bessani, Miguel Correia, Nuno Ferreira Neves, Paulo Verissimo
Issue Date:December 2007
pp. 373-380
Previous works have studied how to use proactive recovery to build intrusion-tolerant replicated systems that are resilient to any number of faults, as long as recoveries are faster than an upper-bound on fault production assumed at system deployment time....
 
Proactive Resilience Revisited: The Delicate Balance Between Resisting Intrusions and Remaining Available
Found in: Reliable Distributed Systems, IEEE Symposium on
By Paulo Sousa, Nuno Ferreira Neves, Paulo Verissimo, William H. Sanders
Issue Date:October 2006
pp. 71-82
In a recent paper, we presented proactive resilience as a new approach to proactive recovery, based on architectural hybridization. We showed that, with appropriate assumptions about fault rate, proactive resilience makes it possible to build distributed i...
 
How Resilient are Distributed f Fault/Intrusion-Tolerant Systems?
Found in: Dependable Systems and Networks, International Conference on
By Paulo Sousa, Nuno Ferreira Neves, Paulo Veríssimo
Issue Date:July 2005
pp. 98-107
Fault-tolerant protocols, asynchronous and synchronous alike, make stationary fault assumptions: only a fraction f of the total n nodes may fail. Whilst a synchronous protocol is expected to have a bounded execution time, an asynchronous one may execute fo...
 
Designing Modular and Redundant Cyber Architectures for Process Control: Lessons learned
Found in: Hawaii International Conference on System Sciences
By Paulo Verissimo, Alysson Neves Bessani, Miguel Correia, Nuno Ferreira Neves, Paulo Sousa
Issue Date:January 2009
pp. 1-8
An architecture was recently proposed to protect the power grid, in the context of a European project. The design of the architecture, guided by an analysis of the evolution of critical information infrastructures, tried to be as generic as possible, with ...
   
Information Assurance Technology Forecast 2008
Found in: IEEE Security and Privacy
By Steven M. Bellovin, Terry V. Benzel, Bob Blakley, Dorothy E. Denning, Whitfield Diffie, Jeremy Epstein, Paulo Verissimo
Issue Date:January 2008
pp. 16-23
A virtual roundtable (featuring panelists Steven Bellovin, Terry Benzel, Bob Blakely, Dorothy Denning, Whitfield Diffie, Jeremy Epstein, and Paulo Verissimo) discussing the next 15 years in computer security.
 
Resilient State Machine Replication
Found in: Pacific Rim International Symposium on Dependable Computing, IEEE
By Paulo Sousa, Nuno Ferreira Neves, Paulo Verissimo
Issue Date:December 2005
pp. 305-309
Nowadays, one of the major concerns about the services provided over the Internet is related to their availability. Replication is a well known way to increase the availability of a service. However, replication has some associated costs, namely it is nece...
 
Dependable Adaptive Real-Time Applications in Wormhole-based Systems
Found in: Dependable Systems and Networks, International Conference on
By Pedro Martins, Paulo Sousa, António Casimiro, Paulo Veríssimo
Issue Date:July 2004
pp. 567
This paper describes and discusses the work carried on in the context of the CORTEX project, for the development of adaptive real-time applications in wormhole based systems. The architecture of CORTEX relies on the existence of a timeliness wormhole, call...
 
Guest Editorial for the Special Issue on the 2005 IEEE/IFIP Conference on Dependable Systems and Networks, including the Dependable Computing and Communications and Performance and Dependability Symposia
Found in: IEEE Transactions on Dependable and Secure Computing
By Jean Arlat, Andrea Bondavalli, Boudewijn Haverkort, Paulo Veríssimo
Issue Date:July 2006
pp. 169-171
No summary available.
 
The Third International Workshop on Dependability of Clouds, Data Centers and Virtual Machine Technology DCDV 2013
Found in: 2013 43rd Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN)
By Jogesh K. Muppala,Matti Hiltunen,Roy Campbell,Paulo Verissimo
Issue Date:June 2013
pp. 1-2
The Third International Workshop on Dependability of Clouds, Data Centers, and Virtual Machine Technology (DCDV 2013) features papers covering various aspects of dependability and security in Clouds and Data Centers. Four sessions covering Cloud and Data C...
 
Efficient Byzantine Fault-Tolerance
Found in: IEEE Transactions on Computers
By Giuliana Santos Veronese,Miguel Correia,Alysson Neves Bessani,Lau Cheuk Lung,Paulo Verissimo
Issue Date:January 2013
pp. 16-30
We present two asynchronous Byzantine fault-tolerant state machine replication (BFT) algorithms, which improve previous algorithms in terms of several metrics. First, they require only 2f+1 replicas, instead of the usual 3f+1. Second, the trusted service i...
 
Reverse Engineering of Protocols from Network Traces
Found in: Reverse Engineering, Working Conference on
By João Antunes,Nuno Neves,Paulo Verissimo
Issue Date:October 2011
pp. 169-178
Communication protocols determine how network components interact with each other. Therefore, the ability to derive a specification of a protocol can be useful in various contexts, such as to support deeper black-box testing or effective defense mechanisms...
 
Recursive virtual machines for advanced security mechanisms
Found in: Dependable Systems and Networks Workshops
By Bernhard Kauer,Paulo Verissimo,Alysson Bessani
Issue Date:June 2011
pp. 117-122
Virtualization contributes to the optimization and modularization of resource usage in a machine. Furthermore, many systems have relied on a virtualization layer to provide extra security functionality. Both features rank amongst the most important of the ...
 
Randomized Consensus in Wireless Environments: A Case Where More is Better
Found in: Dependability, International Conference on
By Bruno Vavala, Nuno Neves, Henrique Moniz, Paulo Veríssimo
Issue Date:July 2010
pp. 7-12
In many emerging wireless scenarios, consensus among nodes represents an important task that must be accomplished in a timely and dependable manner. However, the sharing of the radio medium and the typical communication failures of such environments may se...
 
RITAS: Services for Randomized Intrusion Tolerance
Found in: IEEE Transactions on Dependable and Secure Computing
By Henrique Moniz, Nuno Ferreira Neves, Miguel Correia, Paulo Verissimo
Issue Date:January 2011
pp. 122-136
Randomized agreement protocols have been around for more than two decades. Often assumed to be inefficient due to their high expected communication and computation complexities, they have remained overlooked by the community-at-large as a valid solution fo...
 
Finite Memory: A Vulnerability of Intrusion-Tolerant Systems
Found in: Network Computing and Applications, IEEE International Symposium on
By Giuliana Santos Veronese, Miguel Correia, Lau Cheuck Lung, Paulo Verissimo
Issue Date:July 2008
pp. 37-44
In environments like the Internet, faults follow unusualpatterns, dictated by the combination of malicious attackswith accidental faults such as long communication delayscaused by temporary network partitions. In this scenario,attackers can force buffer ov...
 
Intrusion Tolerance in Wireless Environments: An Experimental Evaluation
Found in: Pacific Rim International Symposium on Dependable Computing, IEEE
By Henrique Moniz, Nuno Ferreira Neves, Miguel Correia, António Casimiro, Paulo Veríssimo
Issue Date:December 2007
pp. 357-364
This paper presents a study on the performance of intrusion-tolerant protocols in wireless LANs. The protocols are evaluated in several different environmental settings, and also within the context of a car platooning application for distributed cruise con...
 
On the Effects of Finite Memory on Intrusion-Tolerant Systems
Found in: Pacific Rim International Symposium on Dependable Computing, IEEE
By Giuliana Santos Veronese, Miguel Correia, Lau Cheuk Lung, Paulo Verissimo
Issue Date:December 2007
pp. 401-404
Intrusion tolerance has been proposed as a new paradigm for computer systems security [2, 7]. The idea is to apply the fault tolerance paradigm in the domain of systems security, accepting that malicious faults (attacks, intrusions) can never be entirely p...
 
Experimental Comparison of Local and Shared Coin Randomized Consensus Protocols
Found in: Reliable Distributed Systems, IEEE Symposium on
By Henrique Moniz, Nuno Ferreira Neves, Miguel Correia, Paulo Verissimo
Issue Date:October 2006
pp. 235-244
The paper presents a comparative performance study of the two main classes of randomized binary consensus protocols: a local coin protocol, with an expected high communication complexity and cheap symmetric cryptography, and a shared coin protocol, with an...
 
Solving Vector Consensus with a Wormhole
Found in: IEEE Transactions on Parallel and Distributed Systems
By Nuno F. Neves, Miguel Correia, Paulo Veríssimo
Issue Date:December 2005
pp. 1120-1131
<p><b>Abstract</b>—This paper presents a solution to the vector consensus problem for Byzantine asynchronous systems augmented with wormholes. Wormholes prefigure a hybrid distributed system model, embodying the notion of an enhanced part...
 
Trustworthiness of Open Information Systems: How Should It Be Achieved?
Found in: Reliable Distributed Systems, IEEE Symposium on
By Paulo Veríssimo
Issue Date:October 2003
pp. 315
No summary available.
   
The Timely Computing Base Model and Architecture
Found in: IEEE Transactions on Computers
By Paulo Veríssimo, António Casimiro
Issue Date:August 2002
pp. 916-930
<p>Current systems are very often based on large-scale, unpredictable, and unreliable infrastructures. However, users of these systems increasingly require services with timeliness properties. This creates a difficult-to-solve contradiction with rega...
 
Measuring Distributed Durations with Stable Errors
Found in: Real-Time Systems Symposium, IEEE International
By Antonio Casimir, Pedro Martins, Luis Rodrigues, Paulo Veríssimo
Issue Date:December 2001
pp. 310
The round-trip duration measurement technique is fundamental to solve many problems in asynchronous distributed systems. In essence, this technique provides the means for reading remote clocks with a known and bounded error. Therefore, it is used as a fund...
 
Efficient Communication in a Design Environment
Found in: Design Automation Conference
By Idalina Videira, Paulo Veríssimo, Helena Sarmento
Issue Date:June 1996
pp. 169-174
This paper presents a new communication service. The novelty of the work resides in the distributed architecture adopted which is based on communication agents in every tool and in every host of the design environment. The importance of the work is demonst...
 
On the Feasibility of Byzantine Fault-Tolerant MapReduce in Clouds-of-Clouds
Found in: 2012 IEEE 31st International Symposium on Reliable Distributed Systems (SRDS)
By Miguel Correia,Pedro Costa,Marcelo Pasin,Alysson Bessani,Fernando Ramos,Paulo Verissimo
Issue Date:October 2012
pp. 448-453
MapReduce is a framework for processing large data sets largely used in cloud computing. MapReduce implementations like Hadoop can tolerate crashes and file corruptions, but there is evidence that general arbitrary faults do occur and can affect the correc...
   
How to Tolerate Half Less One Byzantine Nodes in Practical Distributed Systems
Found in: Reliable Distributed Systems, IEEE Symposium on
By Miguel Correia, Nuno Ferreira Neves, Paulo Veríssimo
Issue Date:October 2004
pp. 174-183
The application of dependability concepts and techniques to the design of secure distributed systems is raising a considerable amount of interest in both communities under the designation of intrusion tolerance. However, practical intrusion-tolerant replic...
 
Node Failure Detection and Membership in CANELy
Found in: Dependable Systems and Networks, International Conference on
By José Rufino, Paulo Veríssimo, Guilherme Arroz
Issue Date:June 2003
pp. 331
<p>Fault-tolerant distributed systems based on fieldbuses may benefit to a great extent from the availability of semantically rich communication services, such as those provided by group communication, clock synchronization, membership and failure de...
 
Generic Timing Fault Tolerance using a Timely Computing Base
Found in: Dependable Systems and Networks, International Conference on
By António Casimiro, Paulo Veríssimo
Issue Date:June 2002
pp. 27
<p>Designing applications with timeliness requirements in environments of uncertain synchrony is known to be a difficult problem. In this paper, we follow the perspective of timing fault tolerance: timing errors occur, and they are processed using re...
 
The Architecture of a Secure Group Communication System Based on Intrusion Tolerance
Found in: Distributed Computing Systems Workshops, International Conference on
By Miguel Correia, Paulo Verissimo, Nuno Ferreira Neves
Issue Date:April 2001
pp. 0017
Abstract: This paper presents the architecture of a secure group communication system with the fortress model of trust, where the participants of the group equally trust one another. We consider that only a small part of the system, a component called the ...
 
The Timely Computing Base: Timely Actions in the Presence of Uncertain Timeliness
Found in: Dependable Systems and Networks, International Conference on
By Paulo Veríssimo, António Casimiro, Christof Fetzer
Issue Date:June 2000
pp. 533
Real-time behavior is specified in compliance with timeliness requirements, which in essence calls for synchronous system models. However, systems often rely on unpredictable and unreliable infrastructures that suggest the use of asynchronous models. Sever...
 
A Columbus' Egg Idea for CAN Media Redundancy
Found in: Fault-Tolerant Computing, International Symposium on
By Jose Rufino, Paulo Verissimo, Guilherme Arroz
Issue Date:June 1999
pp. 286
Network media redundancy is a clean and effective way of achieving high levels of reliability against temporary medium faults and availability in the presence of permanent faults. This is specially true of critical control applications such as those suppor...
 
Embedded Platforms for Distributed Real-Time Computing: Challenges and Results
Found in: Object-Oriented Real-Time Distributed Computing, IEEE International Symposium on
By José Rufino, Guilherme Arroz, Paulo Veríssimo
Issue Date:May 1999
pp. 147
Object-oriented techniques have been along the last decade one of the most useful programming paradigms. However, for distributed embedded systems the semantic gap between the object-orientationlayer and the underlying infrastructure is extremely large. Th...
 
Timing Failure Detection and Real-Time Group Communication in Quasi-Synchronous Systems
Found in: Real-Time Systems, Euromicro Conference on
By Carlos Almeida, Paulo Verissimo
Issue Date:June 1996
pp. 0230
This paper addresses the problem of having real-time group communication in systems that are not completely synchronous (quasi-synchronous). This situation can happen when load is not completely controlled thus not ruling out overload scenarios. This is us...
 
Reliable Computing Over Mobile Networks
Found in: Future Trends of Distributed Computing Systems, IEEE International Workshop
By Luis E.T. Rodrigues, Henrique Fonseca, Paulo Verissimo
Issue Date:August 1995
pp. 0488
Mobile networks and hosts have assumed an increasing importance in recent years and will pervade future distributed computing systems. In order to meet user requirements for reliable operation over mobile networks, protocols that mitigate their current lim...
 
Towards secure and dependable software-defined networks
Found in: Proceedings of the second ACM SIGCOMM workshop on Hot topics in software defined networking (HotSDN '13)
By Diego Kreutz, Fernando M.V. Ramos, Paulo Verissimo
Issue Date:August 2013
pp. 55-60
Software-defined networking empowers network operators with more flexibility to program their networks. With SDN, network management moves from codifying functionality in terms of low-level device configurations to building software that facilitates networ...
     
Adaptare: Supporting automatic and dependable adaptation in dynamic environments
Found in: ACM Transactions on Autonomous and Adaptive Systems (TAAS)
By Andrea Bondavalli, António Casimiro, Mônica Dixit, Paolo Lollini, Paulo Verissimo
Issue Date:July 2012
pp. 1-25
Distributed protocols executing in uncertain environments, like the Internet or ambient computing systems, should dynamically adapt to environment changes in order to preserve Quality of Service (QoS). In earlier work, it was shown that QoS adaptation shou...
     
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