185 research outputs found
Descrição, Geração e Difusão de Políticas de Segurança
Neste artigo é apresentada uma ferramenta de descrição de Políticas de Segurança,
baseada na linguagem SPSL (Security Policy Specification Language). A ferramenta
permite efectuar a descrição de políticas de segurança posteriormente utilizadas na
criação e difusão de regras reconhecidas por vários equipamentos na implementação
das políticas de segurança das organizações
Gestão por políticas: arquitectura e aplicações
Neste artigo é feita uma abordagem à gestão de redes baseadas em políticas focando a
arquitectura PBN (Policy-Based Networking) proposta no âmbito do grupo de trabalho Policy
Framework do IETF (Internet Engineering Task Force). São evidenciados os principais aspectos
desta arquitectura, desde os protocolos de comunicação até às linguagens de especificação de
políticas, passando pelos modelos necessários à representação de informação.
Relativamente às linguagens de especificação de políticas, apresenta-se uma visão geral sobre a
sua aplicabilidade na arquitectura PBN. No âmbito dos protocolos de difusão de política, destacase
o protocolo COPS (Common Open Policy Service) e COPS-PR (COPS for Policy provisioning).
O artigo termina com a descrição de uma aplicação de gestão de firewalls através do uso de
políticas. Esta aplicação baseia-se na arquitectura de gestão por políticas (PBN) proposta e aplica
a linguagem SPSL e o protocolo COPS-PR
Policy Based and Trust Management for Critical Infrastructure Protection
http://cmuportugal.org/tiercontent.aspx?id=2940Critical infrastructure (CI) services are consumed by the society constantly and we expect them to be available 24 hours a day. A common definition is that CIs are so vital to our society that a disruption or destruction would have a severe impact on the social well-being and the economy on a national and an international level. CIs can be mutually dependent on each other and a failure in one infrastructure can cascade to another interdependent infrastructure to cause service disruptions. Methods to better assess and monitor CIs and their interdependencies in order to predict possible risks have to be developed.
This work addresses the problem of the quality of information exchanged among interconnected CI, the quality of the relationship in terms of trust and security and the use of Trust and Reputation management along with the Policy Based Management paradigm is the proposed solution to be applied at the CI interconnection points for information exchange
Is FFT Fast Enough for Beyond-5G Communications?
This paper studies the impact of computational complexity on the throughput
limits of different Discrete Fourier Transform (DFT) algorithms (such as FFT
and straightforward DFT) in the context of OFDM-based waveforms. Based on the
spectro-computational complexity (SC) analysis, it is verified that the
complexity of an -point FFT grows faster than the number of bits in the OFDM
symbol. Thus, the useful throughput of FFT nullifies on . Also, because FFT
demands to be a power of two (), the spectrum widening leads to
an exponential complexity on , i.e. . To overcome these
limitations, we consider the alternative frequency-time transform formulation
of Vector OFDM (V-OFDM), in which an -point FFT is replaced by
() smaller -point FFTs to mitigate the cyclic prefix overhead of
OFDM. Building on that, we replace FFT by the straightforward DFT algorithm to
release the V-OFDM parameters from growing as powers of two and to benefit from
flexible numerology (e.g., , ). Besides, by setting to
, the resulting solution can run linearly on (rather than
exponentially on ) while sustaining a non null throughput as grows.Comment: This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
Restrospectiva do Helicosiphon biscoeensis Gravier, 1907 (Polychaeta: Serpulidae):\ud características morfológicas e ecológicas
This note gathers the main information and illustrations published concerning the Antarctic/Subantarctic polychaete Helicosiphon biscoeensis (Spirorbinae). It provides a short historical overview about the knowledge of this species, including information on its morphology and ecology, and contributes new digital images.Esta nota reúne a maior parte das informações e ilustrações publicadas sobre o poliqueta antártico/subantártico Helicosiphon biscoeensis (Spirorbinae), faz uma breve retrospectiva da evolução de seu conhecimento, incluindo considerações sobre sua morfologia e ecologia, e contribui com imagens digitais inéditas.CNPq - 52.0293/2006-1INCT-APACNPq - Process 574018/2008-5FAPERJ - E-26170.023/200
Prospecção Tecnológica em Base de Patentes de Produtos Terapêuticos da Jabuticaba
Flora is an immeasurable source of raw material to subsidize prospecting research for the discovery of new drugs, treatment and cure of diseases. The jabuticaba (Myrciaria cauliflora), a native Brazilian species, has a potential to be explored in the field of human health. Thus, this work aims to carry out a technological prospection study in search of patents that used jabuticaba and its compounds for medicinal purposes. The study is characterized as descriptive and exploratory, with a basic conception, bibliographic type, with a qualitative-quantitative approach. 325 patents were found with the search key used, but only five were considered for this study. China, Brazil and the United States are the countries that deposit the most. The main IPC codes found in the Espacenet base were A23L, A61K, A01N and C12N. The peak of publications took place in 2015, with a small decrease in the following years.A flora é uma fonte imensurável de matéria-prima para subsidiar pesquisas de prospecção para a descoberta de novos fármacos, tratamento e cura de enfermidades. A jabuticaba (Myrciaria cauliflora), uma espécie nativa brasileira, possui um potencial a ser explorado no campo da saúde humana. Assim, este trabalho tem como objetivo realizar um estudo de prospecção tecnológica em busca de patentes que empregaram a jabuticaba e seus compostos para fins medicinais. O estudo é caracterizado como descritivo e exploratório, de concepção básica, tipo bibliográfico, com abordagem quali-quantitativa. Foram encontradas 325 patentes com a chave de busca utilizada, mas apenas cinco foram consideradas para este estudo. China, Brasil e Estados Unidos são os países que mais depositam. Os principais códigos IPC encontrados na base do Espacenet foram A23L, A61K, A01N e C12N. O ápice de publicações se deu em 2015, com pequeno decréscimo nos anos seguintes
Análise Experimental de Circuitos Elétricos a Partir de Atividades Presenciais e Controladas Remotamente
In this work, we sought to compare the impact of carrying out experimental activities, in person and remotely controlled, on the learning of concepts related to electrical circuits by high school students in five public schools in the interior of São Paulo. In each school, two third-year classes were applied, one group submitted to the face-to-face experiment and the other to the remote experiment. The experiments addressed the concepts of association of resistors, electric current, electric voltage and dissipated electric power.Data were collected through questionnaires, pre-test and post-test, and analyzed using Cohen's D method (1977) and Gery's g factor (1972). Cohen's D method is a statistical measure used to assess the effect size (or magnitude of the difference) between two independent samples, while Gery's g factor is a measure that compares the performance of groups in an experiment, taking into account the individual differences in ability or intelligence. The results indicated that carrying out the experiments played an important role in the students' learning, especially those who participated in the remotely controlled experiment. In addition to offering a contextualized approach to scientific concepts, remote experiments also provided students with the opportunity to manipulate real experiments at any place and time, becoming a promising activity method for Science Teaching. Therefore, the study suggests that the carrying out remote experiments can be an effective and safe way to promote the learning of scientific concepts by high school students, complementing face-to-face activities and allowing greater flexibility in carrying out experimental activities.En este trabajo, buscamos comparar el impacto de la realización de actividades experimentales, presenciales y teledirigidas, en el aprendizaje de conceptos relacionados con los circuitos eléctricos por parte de estudiantes de secundaria en cinco escuelas públicas del interior de São Paulo. En cada escuela se aplicaron dos clases de tercer año, un grupo sometido al experimento presencial y el otro al experimento a distancia. Ambos abordaron los conceptos de asociación de resistencias, corriente eléctrica, voltaje eléctrico y potencia eléctrica disipada. Los datos fueron recolectados a través de cuestionarios, pretest y postest, y analizados a través del método D de Cohen (1977) y el factor g de Gery (1972). El primero consiste en una medida estadística utilizada para evaluar el tamaño del efecto (o la magnitud de la diferencia) entre dos muestras independientes, mientras que el factor g de Gery es una medida que compara el desempeño de los grupos en un experimento, teniendo en cuenta las diferencias individuales en capacidad o inteligencia. Los resultados indicaron que los experimentos cumplieron un papel importante en el aprendizaje de los estudiantes, especialmente de quienes que participaron en el controlado a distancia. Además de ofrecer un acercamiento contextualizado a los conceptos científicos, los experimentos remotos también brindaron a los estudiantes la oportunidad de manipular experimentos reales en cualquier lugar y momento; en este sentido, se convirtieron en un método prometedor para la Enseñanza de las Ciencias; en una forma eficaz y segura de promover el aprendizaje de conceptos científicos por parte de los estudiantes de secundaria; y en un complemento de las actividades presenciales, gracias a que permiten una mayor flexibilidad en su ejecución.In this work, we sought to compare the impact of carrying out experimental activities, in person and remotely controlled, on the learning of concepts related to electrical circuits by high school students in five public schools in the interior of São Paulo. In each school, two third-year classes were applied, one group submitted to the face-to-face experiment and the other to the remote experiment. The experiments addressed the concepts of association of resistors, electric current, electric voltage and dissipated electric power.Data were collected through questionnaires, pre-test and post-test, and analyzed using Cohen's D method (1977) and Gery's g factor (1972). Cohen's D method is a statistical measure used to assess the effect size (or magnitude of the difference) between two independent samples, while Gery's g factor is a measure that compares the performance of groups in an experiment, taking into account the individual differences in ability or intelligence. The results indicated that carrying out the experiments played an important role in the students' learning, especially those who participated in the remotely controlled experiment. In addition to offering a contextualized approach to scientific concepts, remote experiments also provided students with the opportunity to manipulate real experiments at any place and time, becoming a promising activity method for science teaching. Therefore, the study suggests that the carrying out remote experiments can be an effective and safe way to promote the learning of scientific concepts by high school students, complementing face-to-face activities and allowing greater flexibility in carrying out experimental activities
Network Simulation and Performance Evaluation of WiMAX Extensions for Isolated Research Data Networks
IEEE 802.16 is yet a very recent technology and released hardware does frequently only support standards partially. The same applies to public available simulation tools, in particular for NS-2. As the latter is the de-facto standard in science and as we use it for our research in the context of the WEIRD project, we evaluate the IEEE 802.16 support for NS-2. We present several general but also specific issues, which areimportant in order to carry out reliable research based on thesetools. In particular, we show in much detail where modulesdeviate significantly and even fail totally
The EuQoS system: A solution for QoS routing in heterogeneous networks
EuQoS is the acronym for “end-to-end quality of service support over heterogeneous networks,”which is a European research project aimed at building an entire QoS framework,addressing all the relevant network layers, protocols, and technologies. This framework, which includes the most common access networks (xDSL, UMTS, WiFi, and LAN) is being prototyped and tested in a multidomain scenario throughout Europe, composing what we call the EuQoS system. In this article we present the novel QoS routing mechanisms that are being
developed and evaluated in the framework of this project. The preliminary performance results validate the design choices of the EuQoS system, and confirm the potential impact this project is likely to have in the near future.Postprint (published version
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