1,684 research outputs found
The web of federal crimes in Brazil: topology, weaknesses, and control
Law enforcement and intelligence agencies worldwide struggle to find
effective ways to fight and control organized crime. However, illegal networks
operate outside the law and much of the data collected is classified.
Therefore, little is known about criminal networks structure, topological
weaknesses, and control. In this contribution we present a unique criminal
network of federal crimes in Brazil. We study its structure, its response to
different attack strategies, and its controllability. Surprisingly, the network
composed of multiple crimes of federal jurisdiction has a giant component,
enclosing more than a half of all its edges. This component shows some typical
social network characteristics, such as small-worldness and high clustering
coefficient, however it is much "darker" than common social networks, having
low levels of edge density and network efficiency. On the other side, it has a
very high modularity value, . Comparing multiple attack strategies, we
show that it is possible to disrupt the giant component of the network by
removing only of its edges or nodes, according to a module-based
prescription, precisely due to its high modularity. Finally, we show that the
component is controllable, in the sense of the exact network control theory, by
getting access to of the driver nodes.Comment: 9 pages, 5 figure
Complex networks vulnerability to module-based attacks
In the multidisciplinary field of Network Science, optimization of procedures
for efficiently breaking complex networks is attracting much attention from
practical points of view. In this contribution we present a module-based method
to efficiently break complex networks. The procedure first identifies the
communities in which the network can be represented, then it deletes the nodes
(edges) that connect different modules by its order in the betweenness
centrality ranking list. We illustrate the method by applying it to various
well known examples of social, infrastructure, and biological networks. We show
that the proposed method always outperforms vertex (edge) attacks which are
based on the ranking of node (edge) degree or centrality, with a huge gain in
efficiency for some examples. Remarkably, for the US power grid, the present
method breaks the original network of 4941 nodes to many fragments smaller than
197 nodes (4% of the original size) by removing mere 164 nodes (~3%) identified
by the procedure. By comparison, any degree or centrality based procedure,
deleting the same amount of nodes, removes only 22% of the original network,
i.e. more than 3800 nodes continue to be connected after thatComment: 8 pages, 8 figure
Portuguese consumers and made in Portugal luxury - what perception?
For many years, the Country of Origin (COO)effect and luxury were under the analysis of many studies. Nevertheless, little research has been conducted about the Portuguese market and its consumers. Therefore, this work project aims to provide a deeper understanding of the case of Portugal in the luxury field and comprehend the perceptions of the Portuguese consumers regarding the luxury products made in Portugal. The research methodology was focused on a quantitative approach using an online survey that allowed testing the hypothesis created, which were based on the literature review. Additionally, from the analysis of the data, theoretical and practical implications and recommendations were extracted. The primary beneficiaries are business owners, responsible institutions and authorities, and future research
Preparation and evaluation of material properties of biofilms from spruce xylan
Tese de mestrado integrado. Engenharia QuÃmica. Universidade do Porto. Faculdade de Engenharia. 201
Mecanismos dinâmicos de segurança para redes softwarizadas e virtualizadas
The relationship between attackers and defenders has traditionally been
asymmetric, with attackers having time as an upper hand to devise an exploit
that compromises the defender. The push towards the Cloudification of
the world makes matters more challenging, as it lowers the cost of an attack,
with a de facto standardization on a set of protocols. The discovery of a vulnerability
now has a broader impact on various verticals (business use cases),
while previously, some were in a segregated protocol stack requiring independent
vulnerability research. Furthermore, defining a perimeter within a cloudified
system is non-trivial, whereas before, the dedicated equipment already
created a perimeter. This proposal takes the newer technologies of network
softwarization and virtualization, both Cloud-enablers, to create new dynamic
security mechanisms that address this asymmetric relationship using novel
Moving Target Defense (MTD) approaches. The effective use of the exploration
space, combined with the reconfiguration capabilities of frameworks like
Network Function Virtualization (NFV) and Management and Orchestration
(MANO), should allow for adjusting defense levels dynamically to achieve the
required security as defined by the currently acceptable risk. The optimization
tasks and integration tasks of this thesis explore these concepts. Furthermore,
the proposed novel mechanisms were evaluated in real-world use cases, such
as 5G networks or other Network Slicing enabled infrastructures.A relação entre atacantes e defensores tem sido tradicionalmente assimétrica,
com os atacantes a terem o tempo como vantagem para conceberem
uma exploração que comprometa o defensor. O impulso para a Cloudificação
do mundo torna a situação mais desafiante, pois reduz o custo de um
ataque, com uma padronização de facto sobre um conjunto de protocolos.
A descoberta de uma vulnerabilidade tem agora um impacto mais amplo em
várias verticais (casos de uso empresarial), enquanto anteriormente, alguns
estavam numa pilha de protocolos segregados que exigiam uma investigação
independente das suas vulnerabilidades. Além disso, a definição de um
perÃmetro dentro de um sistema Cloud não é trivial, enquanto antes, o equipamento
dedicado já criava um perÃmetro. Esta proposta toma as mais recentes
tecnologias de softwarização e virtualização da rede, ambas facilitadoras da
Cloud, para criar novos mecanismos dinâmicos de segurança que incidem sobre
esta relação assimétrica utilizando novas abordagens de Moving Target
Defense (MTD). A utilização eficaz do espaço de exploração, combinada com
as capacidades de reconfiguração de frameworks como Network Function
Virtualization (NFV) e Management and Orchestration (MANO), deverá permitir
ajustar dinamicamente os nÃveis de defesa para alcançar a segurança
necessária, tal como definida pelo risco actualmente aceitável. As tarefas de
optimização e de integração desta tese exploram estes conceitos. Além disso,
os novos mecanismos propostos foram avaliados em casos de utilização no
mundo real, tais como redes 5G ou outras infraestruturas de Network Slicing.Programa Doutoral em Engenharia Informátic
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