300 research outputs found
Engineering the application of machine learning in an IDS based on IoT traffic flow
Internet of Things (IoT) devices are now widely used, enabling intelligent services that, in association with
new communication technologies like the 5G and broadband internet, boost smart-city environments. Despite
their limited resources, IoT devices collect and share large amounts of data and are connected to the internet,
becoming an attractive target for malicious actors. This work uses machine learning combined with an Intrusion Detection System (IDS) to detect possible attacks. Due to the limitations of IoT devices and low latency services, the IDS must have a specialized architecture. Furthermore, although machine learning-based solutions have high potential, there are still challenges related to training and generalization, which may impose constraints on the architecture. Our proposal is an IDS with a distributed architecture that relies on Fog computing to run specialized modules
and use deep neural networks to identify malicious traffic inside IoT data flows. We compare our IoT-Flow
IDS with three other architectures. We assess model generalization using test data from different datasets and
evaluate their performance in terms of Recall, Precision, and F1-Score. Results confirm the feasibility of flowbased anomaly detection and the importance of network traffic segmentation and specialized models in the AI-based IDS for IoT.info:eu-repo/semantics/publishedVersio
Extensions of firefly algorithm for nonsmooth nonconvex constrained optimization problems
Publicado em: "Computational science and its applications – ICCSA 2016: 16th International Conference, Beijing, China, July 4-7, 2016, Proceedings, Part I". ISBN 978-3-319-42084-4Firefly Algorithm (FA) is a stochastic population-based algorithm
based on the flashing patterns and behavior of fireflies. Original FA was created
and successfully applied to solve bound constrained optimization problems. In
this paper we present extensions of FA for solving nonsmooth nonconvex
constrained global optimization problems. To handle the constraints of the
problem, feasibility and dominance rules and a fitness function based on the
global competitive ranking, are proposed. To enhance the speed of convergence,
the proposed extensions of FA invoke a stochastic local search procedure.
Numerical experiments to validate the proposed approaches using a set of well
know test problems are presented. The results show that the proposed extensions
of FA compares favorably with other stochastic population-based methods.COMPETE: POCI-01-0145- FEDER-007043FCT – Fundação para a Ciência e Tecnologia within the projects UID/CEC/00319/2013 and UID/MAT/00013/201
A firefly dynamic penalty approach for solving engineering design problems
Firefly Algorithm is a recent swarm intelligence method, inspired by the social behavior of fireflies, based on their flashing and attraction characteristics [1, 2]. In this paper, we analyze the implementation of a dynamic penalty approach combined with the Firefly algorithm for solving constrained global optimization problems. In order to assess the applicability and performance of the proposed method, some benchmark problems from engineering design optimization are considered.The authors would like to thank the financial support from FCT (Fundação para a Ciência e Tecnologia, Portugal) in the scope of the projects: PEst-OE/MAT/UI0013/2014 and PEst-OE/EEI/UI0319/2014
Extension of the firefly algorithm and preference rules for solving MINLP problems
An extension of the firefly algorithm (FA) for solving mixed-integer nonlinear programming (MINLP) problems is
presented. Although penalty functions are nowadays frequently used to handle integrality conditions and inequality and equality
constraints, this paper proposes the implementation within the FA of a simple rounded-based heuristic and four preference rules
to find and converge to MINLP feasible solutions. Preliminary numerical experiments are carried out to validate the proposed
methodology.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundac¸ao para a Ci ˜ encia e Tecnologia, ˆ
within the projects UID/CEC/00319/2013 and UID/MAT/00013/2013.info:eu-repo/semantics/publishedVersio
Comparison of penalty functions on a penalty approach to mixed-integer optimization
In this paper, we present a comparative study involving several penalty functions that can be used in a penalty approach for globally solving bound mixed-integer nonlinear programming (bMIMLP) problems. The penalty approach relies on a continuous reformulation of the bMINLP problem by adding a particular penalty term to the objective function. A penalty function based on the ‘erf’ function is proposed. The continuous nonlinear optimization problems are sequentially solved by the population-based firefly algorithm. Preliminary numerical experiments are carried out in order to analyze the quality of the produced solutions, when compared with other penalty functions available in the literature.The authors would like to thank the financial support from FCT (Fundação para a Ciência e Tecnologia, Portugal) in the scope of the projects: PEst-OE/MAT/UI0013/2014 and PEst-UID/CEC/00319/2013
The first 62 AGN observed with SDSS-IV MaNGA - IV: gas excitation and star-formation rate distributions
We present maps of the ionized gas flux distributions, excitation,
star-formation rate SFR, surface mass density , and obtain total
values of SFR and ionized gas masses {\it M} for 62 Active Galactic Nuclei
(AGN) observed with SDSS-IV MaNGA and compare them with those of a control
sample of 112 non-active galaxies. The most luminous AGN -- with
L(\rm{[OIII]}\lambda 5007) \ge 3.8\times 10^{40}\,\mbox{erg}\,\mbox{s}^{-1},
and those hosted by earlier-type galaxies are dominated by Seyfert excitation
within 0.2 effective radius from the nucleus, surrounded by LINER
excitation or transition regions, while the less luminous and hosted by
later-type galaxies show equally frequent LINER and Seyfert excitation within
. The extent of the region ionized by the AGN follows the
relation -- as in the case of the Broad-Line
Region. The SFR distribution over the region ionized by hot stars is similar
for AGN and controls, while the integrated SFR -- in the range
\,M\,yr is also similar for the late-type
sub-sample, but higher in the AGN for 75\% of the early-type sub-sample. We
thus conclude that there is no signature of AGN quenching star formation in the
body of the galaxy in our sample. We also find that 66\% of the AGN have higher
ionized gas masses than the controls -- in the range
10\,M -- while 75\% of the AGN have higher
within than the control galaxies
Stromal vascular fraction from adipose tissue and cell sheet engineering to build vascularization units for tissue engineering and regenerative medicine
Vascularization holds the gold key for the effective survival and engraftment of complex engineered tissues and organs for Tissue Engineering and Regenerative Medicine. The lack of adequate vascularization post-transplantation often results in cell necrosis and ultimate failure and rejection of the engineered construct. Herein, we propose a strategy capable of surpassing this obstacle. Harnessing easy accessible adipose tissue stromal vascular fraction (SVF) as a source for cells with intrinsic angiogenic potential, and cell sheet technology we were able to engineer cell sheets with high angiogenic potential. SVF was isolated from the adipose tissue of healthy human subjects after enzymatic digestion and 2x105 nucleated cells/well were seeded on 24 well plates for cell sheet formation. To further boost cells’ angiogenic potential, hypoxic conditions of 5% of oxygen were provided to some of the cells while the rest was cultured in typical normoxia, for up to 8 days of culture, in basal medium. Flow cytometry analysis demonstrated the presence of a heterogeneous population of mesenchymal progenitors, endothelial and hematopoietic cells. Furthermore, the proliferation of SVF cells was evaluated through dsDNA quantification, which showed higher numbers for cells in hypoxic conditions, at earlier time points. Immunocytochemistry against CD31 and CD146 revealed the presence of an interconnected and highly branched network of vessel-like structures, more prominent for cells in hypoxia after 5 days of culture and quite similar for both conditions after 8 days, in the absence of any specific media supplementation. In vivo testing using the cell sheets detached from the wells and HIF expression analysis are currently underway. Taken together, the great potentiality of cell sheet technology with SVF cells cultured in hypoxia opens new exciting perspectives and may represent tremendously valuable vascularization units for tissue engineering strategies
Morbidade e sobrevida em AIDS avançada no Rio de Janeiro, Brasil
Opportunistic diseases (OD) are the most common cause of death in AIDS patients. To access the incidence of OD and survival in advanced immunodeficiency, we included 79 patients with AIDS treated at Hospital Evandro Chagas (FIOCRUZ) from September 1997 to December 1999 with at least one CD4 countAs doenças oportunistas (DO) são a causa mais comum de morte em pacientes com AIDS. Para acessar a incidência de DO e a sobrevida na imunodeficiência avançada, foram incluídos 79 pacientes com AIDS tratados no Hospital Evandro Chagas (FIOCRUZ) no período de Setembro de 1997 a Dezembro de 1999, com ao menos uma contagem de células CD
Characterization of Cysticercus bovis lesions at postmortem inspection of cattle by gross examination, histopathology and polymerase chain reaction (PCR)
Considerando a necessidade do conhecimento da cisticercose bovina e do aperfeiçoamento dos métodos de diagnóstico desta doença, objetivou-se verificar a ocorrência do Cysticercus bovis nos diversos locais anatômicos, tais como: cabeça, coração, esôfago, diafragma, língua, fígado e carcaça, examinados pelo Serviço de Inspeção Federal. O diagnóstico foi feito por macroscopia, microscopia e PCR com extração de DNA por fervura para a identificação do metacestóide. Dos 22043 bovinos abatidos, 713 (3,23%) estavam infectados. O coração foi o sítio anatômico mais afetado, com 1,90% (420/22043), seguido da cabeça, 1,11% (245/22043), do esôfago, 0,08% (18/22043), da carcaça, 0,07% (15/22043), do diafragma, 0,03% (7/22043), do fígado, 0,02% (5/22043) e da língua, 0,01% (3/22043). Dos cistos obtidos, 58,35% (416/713) estavam mortos e 41,65% (297/713), vivos. As diferenças entre os sítios anatômicos e a condição morfológica dos cistos foram significativas (p < 0,05). Dos 416 cistos mortos, 253 foram examinados por apresentarem características de: lesões nodulares firmes, brancacentas, com material amarelado, por vezes com aspecto calcário, no interior. O exame microscópico revelou granulomas comumente representados por centro necrótico e/ou mineralizado, envolto por histiócitos dispostos em paliçada, células gigantes multinucleadas, infiltrado misto, predominantemente de mononucleares, e fibrose. Por vezes, a periferia das lesões tinha características de tecido de granulação e mineralização em forma de lâminas lineares. Os restos parasitários foram identificados como um material hialino acelular, contendo elementos ovais e circulares, basofílicos, acidófilos e incolores, denominados corpúsculos calcários. Em algumas lesões foram observados raros corpúsculos, dispersos na reação inflamatória. Nódulos fibrosos, ricos em infiltrado linfóide ou crônico ativos, foram frequentemente visualizados. Dos cistos vivos examinados, 65% (13/20) foram positivos para C. bovis , confirmando o diagnóstico ambulatorial e a eficácia do método de PCR utilizado. Em virtude da positividade observada para C. bovis nos exames histopatológico e PCR, particularmente em fígado e esôfago, sugere-se que seja reformulado o artigo 176 do Regulamento de Inspeção Industrial e Sanitária de Produtos de Origem Animal, incluindo estes locais na rotina de inspeção nos matadouros.Considering the importance of improving methods for diagnosis of bovine Cysticercosis, this study aimed to verify Cysticercus bovis occurrence in different anatomical sites, as head, heart, esophagus, diaphragm, tongue, liver and carcass, examined by federal inspection service. Diagnosis was performed by gross examination, histopatholgy and PCR with boiling DNA extraction for metacestode identification. Of 22043 slaughtered cattle, 713 (3.23%) were infected. The heart was mostly affected with 1.90% (420/22043), followed by head, 1.11% (245/22043), esophagus, 0.08% (18/22043), carcass, 0.07% (15/22043), diaphragm, 0.03% (7/22043), liver, 0.02% (5/22043) and tongue, 0.01% (3/22043). Of the cysts obtained, 58.35% (416/713) were dead and 41.65% (297/713) were alive. The differences among anatomical sites and cysts status were significant (p<0.05). Of the 416 dead cysts 253, characterized by nodular firm whitish lesions, containing yellowish material, some times in calcareous aspect were examined for histopathology. The histological exams of these cysts yielded granulomatous lesions, whose centers were characterized by caseous and/or calcareous material, multinucleate giant cells, histiocytes in palisade and infiltrate composed predominantly by lymphoid cells, wrapped up by fibrosis. Some times the lesions peripheries had granulation tissue and mineralized areas, like linear blade. The parasite debris were like a hyaline, non cellular material with spherical and ovoid, basophilic, eosinophilic and colorless corpuscles. These corpuscles were seen rarely, some times, among inflammatory reaction. Fibrous nodules, rich in lymphoid or mixed infiltrates, were frequently seen. Of the live cysts subjected to PCR with boiling DNA extraction, 65% (13/20) were positive for C. bovis, confirming the ambulatory diagnosis and the efficacy of the PCR procedure used. Due to microscopic and PCR diagnostic exams of C. bovis, mainly in the liver and esophagus, it is suggested changes in the 176 article of the regulatory inspection, by including these sites in the bovine routine inspection at the slaughterhouses
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