DSpace Coleção: DITEL | Artigos publicados em periódicos internacionais
http://hdl.handle.net/10926/1471
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Program matching through code analysis and artificial neural networks
http://hdl.handle.net/10926/1329
Título: Program matching through code analysis and artificial neural networks<br/><br/>Autores: Machado, Raphael Carlos Santos; Nascimento, Tiago Monteiro do; Boccardo, Davidson Rodrigo; Prado, Charles Bezerra do; Carmo, Luiz Fernando Rust da Costa<br/><br/>Resumo: Program matching refers to the mapping between equivalent codes written in differentlanguages - including high-level and low-level languages. This equivalence is useful for some software engineering scenarios such as determining whether rewritten code is cor-rect, which version of a program is being used, and whether a malware is present inthe program. In the present work, we propose a novel approach to solve the executablecode traceability by using program code analysis and arti cial neural networks. Fromthe program code analysis we obtained execution behavior properties of the codes, andfrom the artifcial neural networks we judge about their correspondence. Our evaluationusing real code examples shows an acceptable correspondence rate between 62% and 100% with the very low rate of 4% false positives.<br/><br/>Descrição: 17 p. : il.EWIDS: an extended wireless IDS for metropolitan wireless networks based on kinematical analysis
http://hdl.handle.net/10926/1592
Título: EWIDS: an extended wireless IDS for metropolitan wireless networks based on kinematical analysis<br/><br/>Autores: Pirmez, Luci; Vianna, Nilson Rocha; Correia, Reinaldo de Barros; Carmo, Luiz Fernando Rust da Costa; Farias, Cláudio Miceli de; Salmon, Hélio Mendes<br/><br/>Resumo: Wireless metropolitan area networks (WMANs) are well known to subject users or applications and to a vast gamma of securityrisks, hindering security critical distributed applications from employing this type of network as a communication infrastructure. Most existing approaches for addressing WMAN security issues use cryptography-based mechanisms or ad-hocadapted versions of traditional Intrusion Detection Systems (IDS) for wired networks. While the first approach may lead to unfeasible computation costs for mobile hand-held devices, the second exhibits a high dependency on the freshness of their attack-signature databases, besides not considering any inherent characteristic of wireless networks, such as mobility. Thus, we present EWIDS (Extended Wireless IDS); a lightweight IDS specially designed for WMANs, which detects anomalous wireless device transmissions by employing kinematical analysis on the motion of users’ mobile devices. EWIDS also takes into account the decision information generated by transmitterfingerprint mechanisms used to identify wireless device. Both information is integrated through a fuzzy logic engine in order to increase the system performance. Realistic simulations based on WMAN scenarios revealed that our approach is very promising, since worst-case results have shown high correct alarm rates associated with low false positive rates.<br/><br/>Descrição: 11 p. : il.Genomic distance under gene substitutions
http://hdl.handle.net/10926/1328
Título: Genomic distance under gene substitutions<br/><br/>Autores: Machado, Raphael Carlos Santos; Braga, Marília Dias Vieira; Ribeiro, Leonardo Costa; Stoye, Jens<br/><br/>Resumo: Background: The distance between two genomes is often computed by comparing only the common markersbetween them. Some approaches are also able to deal with non-common markers, allowing the insertion or thedeletion of such markers. In these models, a deletion and a subsequent insertion that occur at the same positionof the genome count for two sorting steps.Results: Here we propose a new model that sorts non-common markers with substitutions, which are morepowerful operations that comprehend insertions and deletions. A deletion and an insertion that occur at the sameposition of the genome can be modeled as a substitution, counting for a single sorting step.Conclusions: Comparing genomes with unequal content, but without duplicated markers, we give a linear timealgorithm to compute the genomic distance considering substitutions and double-cut-and-join (DCJ) operations.This model provides a parsimonious genomic distance to handle genomes free of duplicated markers, that is inpractice a lower bound to the real genomic distances. The method could also be used to refine orthologyassignments, since in some cases a substitution could actually correspond to an unannotated orthology.<br/><br/>Descrição: 9 p. : il.A decomposition for total-coloring partial-grids and list-total-coloring outerplanar graphs
http://hdl.handle.net/10926/1272
Título: A decomposition for total-coloring partial-grids and list-total-coloring outerplanar graphs<br/><br/>Autores: Machado, Raphael Carlos Santos; Figueiredo, Celina Miraglia Herrera de<br/><br/>Resumo: The total chromatic number χT (G) is the least numberof colors sufficient to color the elements (vertices and edges) of a graphG in such away that no incident or adjacent elements receive the same color. In the presentwork,we obtain two results on total-coloring. First, we extend the set of partial-grids classified with respect to thetotal-chromatic number, by proving that every 8-chordal partial-grid of maximum degree 3 has total chromatic number 4. Second, we prove a result on list-total-coloring biconnected outerplanar graphs. If for each element x of a biconnected outerplanar graph G there exists a set Lxof colors such that |Luw| = max{deg(u) + 1, deg(w) + 1} for each edge uw and |Lv| = 7−δdeg(v),3−2δdeg(v),2 (where δi ,j = 1 if i = j and δi ,j = 0 if i = j ) for each vertex v, then there is a total-coloring π of graph G such that π(x) ∈ Lxfor each element x of G. The technique used in these two results is a decomposition by a cutset of two adjacent vertices, whose properties are discussed in the article.<br/><br/>Descrição: 9 p. : il.