João Bispo

João Bispo

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2006
Verified
Conference Paper
Closed access
JBJoão Bispo
João Bispo
ISIoannis Sourdis
Ioannis Sourdis
João CardosoJoão Cardoso
João Cardoso
SVStamatis Vassiliadis
Stamatis Vassiliadis
Recent intrusion detection systems (IDS) use regular expressions instead of static patterns as a more efficient way to represent hazardous packet payload contents. This paper focuses on regular expressions pattern matching engines implemented in reconfigurable hardware. A nondeterministic finite automata (NFA) based implementation was presented, which takes advantage of new basic building blocks to support more complex regular expressions than the previous approaches. The methodology is supported by a tool that automatically generates the circuitry for the given regular expressions, outputting VHDL representations ready for logic synthesis. Furthermore, techniques to reduce the area cost of our designs and maximize performance when targeting FPGAs were included. Experimental results show that our tool is able to generate a regular expression engine to match more than 500 IDS regular expressions (from the Snort ruleset) using only 25K logic cells and achieving 2 Gbps throughput on a Virtex2 and 2.9 on a Virtex4 device. Concerning the throughput per area required per matching non-meta character, our design is 3.4 and 10 times more efficient than previous ASIC and FPGA approaches, respectively

4 October 2007 in Journal of Signal Processing Systems
Verified
Journal Article
Open access
PDF file
ISIoannis Sourdis
Ioannis Sourdis
JBJoão Bispo
João Bispo
João CardosoJoão Cardoso
João Cardoso
SVStamatis Vassiliadis
Stamatis Vassiliadis
In this paper we describe a regular expression pattern matching approach for reconfigurable hardware. Following a Non-deterministic Finite Automata direction, we introduce three new basic building blocks to support constraint repetitions syntaxes more efficiently than previous works. In addition, a number of optimization techniques are employed to reduce the area cost of the designs and maximize performance. Our design methodology is supported by a tool that automatically generates the circuitry for the given regular expressions and outputs Hardware Description Language representations ready for logic synthesis. The proposed approach is evaluated on network Intrusion Detection Systems (IDS). Recent IDS use regular expressions to represent hazardous packet payload contents. They require high-speed packet processing providing a challenging case study for pattern matching using regular expressions. We use a number of IDS rulesets to show that our approach scales well as the number of regular expressions increases, and present a step-by-step optimization to survey the benefits of our techniques. The synthesis tool described in this study is used to generate hardware engines to match 300 to 1,500 IDS regular expressions using only 10–45 K logic cells and achieving throughput of 1.6–2.2 and 2.4–3.2 Gbps on Virtex2 and Virtex4 devices, respectively. Concerning the throughput per area required per matching non-Meta character, our hardware engines are 10–20× more efficient than previous Field Programmable Gate Array approaches. Furthermore, the generated designs have comparable area requirements to current application-specific integrated circuit solutions.

16 May 2016
Verified
Conference Paper
Open access
CSCristina Silvano
Cristina Silvano
Giovanni AgostaGiovanni Agosta
Giovanni Agosta
SCStefano Cherubin
Stefano Cherubin
DGDavide Gadioli
Davide Gadioli
GPGianluca Palermo
Gianluca Palermo
ERErven Rohou
Erven Rohou
The ANTAREX project aims at expressing the application self-adaptivity through a Domain Specific Language (DSL) and to runtime manage and autotune applications for green and heterogeneous High Performance Computing (HPC) systems up to Exascale. The DSL approach allows the definition of energy-efficiency, performance, and adaptivity strategies as well as their enforcement at runtime through application autotuning and resource and power management. We show through a mini-app extracted from one of the project application use cases some initial exploration of application precision tuning by means enabled by the DSL.

3 June 2007
Verified
Book Chapter
Closed access
PDF file
JBJoão Bispo
João Bispo
ISIoannis Sourdis
Ioannis Sourdis
João CardosoJoão Cardoso
João Cardoso
SVStamatis Vassiliadis
Stamatis Vassiliadis

20 June 2021
Verified
Conference Paper
Open access
GTGil Teixeira
Gil Teixeira
JBJoão Bispo
João Bispo
FCFilipe Correia
Filipe Correia
We propose a mechanism to raise the abstraction level of source-code analysis and robustly support multiple languages. Built on top of the LARA framework, it allows sharing language specifications between LARA source-to-source compilers, and enables the mapping of a virtual AST over the nodes of ASTs provided by different, unrelated parsers. We use this approach to create a language specification for Object-Oriented (OO) languages and add support for three different LARA compilers. We evaluate it by implementing a library of 18 software metrics using this language specification and apply the metrics to source code in four programming languages (C, C++, Java, and JavaScript). We compare the results with other tools to evaluate the approach.

1 September 2018 in Computer Languages, Systems & Structures
Verified
Journal Article
Closed access
PPPedro Pinto
Pedro Pinto
TCTiago Carvalho
Tiago Carvalho
JBJoão Bispo
João Bispo
MRMiguel António Ramalho
Miguel António Ramalho
João CardosoJoão Cardoso
João Cardoso