Lightweight Security for Network Coding

Under the emerging network coding paradigm, intermediate nodes in the network are allowed not only to store and forward packets but also to process and mix different data flows. We propose a low-complexity cryptographic scheme that exploits the inherent security provided by random linear network coding and offers the advantage of reduced overhead in comparison to traditional end-to-end encryption of the entire data. Confidentiality is achieved by protecting (or "locking") the source coefficients required to decode the encoded data, without preventing intermediate nodes from running their standard network coding operations. Our scheme can be easily combined with existing techniques that counter active attacks.Comment: Proc. of the IEEE International Conference on Communications (ICC 2008), Beijing, China, May 200

Tailoring PMI and OGC frameworks for IT project portfolio management

Tese de Doutoramento - Programa Doutoral em Tecnologias e Sistemas de InformaçãoPrivate non-profit organizations that are dedicated to developing research and development (R&D) projects with the University, through a context of interface between Universities and companies, are currently recognized in Portugal as Technological Interface Centres. These organizations develop applied research projects between TRL 4 and 8 for companies in close collaboration with the research units of the Universities. As with any organization with no budget coming from the state, its main strategy is to efficiently and effectively manage the project portfolio to ensure control of execution costs as well as the expected quality of projects delivered to customers and partners. The currently available project portfolio management frameworks are not sufficiently clear as to how processes or practices suggested to practitioners should effectively be applied. In the specific field of Information Technology (IT), there is at least one framework for supporting portfolios management, but the level of detail in the adoption of the practices is (insufficiently) generic. This thesis intends to configure an IT project portfolios management framework, based on the coordinated (extended subsets) adaptation of the two main frameworks currently in the area: PMI and OGC. This configuration required the alignment between PMI and OGC frameworks, through a map of dependencies between processes, as well as the mapping between artefacts and processes. As a case study to test this framework, a Portuguese organization was chosen, formally recognized as a Technological Interface Centre, where two portfolios of IT projects in R&D contexts were characterized and analysed in light of the framework's techniques.As organizações privadas sem fins lucrativos que se dedicam a desenvolver projetos de investigação e desenvolvimento junto das Universidades, através de um contexto de interface entre Universidades e empresas, são atualmente reconhecidas em Portugal, como Centros de Interface Tecnológicos. Estas organizações desenvolvem projetos de investigação aplicada entre TRL 4 e 8 para as empresas, em colaboração estreita com as Unidades de Investigação das Universidades. Como em qualquer organização, sem orçamento proveniente do Estado, a sua estratégia principal é gerir com eficiência e eficácia o portfólio de projetos, de modo a garantir o controlo dos custos de execução, bem como a expetativa de qualidade dos projetos entregues aos clientes e parceiros. As frameworks de gestão de portfólio de projetos atualmente disponíveis não são suficientemente claras em relação à forma como processos ou práticas sugeridas aos profissionais devem efetivamente ser aplicados. No domínio específico das Tecnologias da Informação (TI) existe, pelo menos, uma framework de suporte à gestão de portfólios, mas o nível de detalhe na adoção das práticas é (insuficientemente) genérico. Com esta tese pretende-se configurar uma framework de gestão de portfólios de projetos de TI, a partir da adaptação coordenada (extended subsets) das duas principais frameworks atualmente existentes na área: a do PMI e a do OGC. A referida configuração exigiu o alinhamento entre frameworks do PMI e OGC através dum mapa de dependências entre processos, bem como o mapeamento entre artefactos e processos. Como estudo de caso para experimentar a referida framework, foi selecionada uma organização portuguesa, formalmente reconhecida como Centro de Interface Tecnológico, onde dois portfólios de projetos de TI em contextos de I&D foram caracterizados e analisados à luz das técnicas da referida framework.Este trabalho foi desenvolvido com o apoio financeiro da Associação CCG/ZGDV – Centro de Computação Gráfica

Por uma Curadoria Operária

"No último 28 de outubro, confirmou-se uma tragédia no país. A farsa e a violência foram estratégias muito bem conduzidas para eleger um político, irrelevante nos seus 30 anos de mandatos legislativos, de características fascistas como o 38o. presidente do Brasil. Mais de 57 milhões de pessoas legitimaram a aniquilação da possibilidade de vida plural tornando afrodescendentes, povos originários, a população LGBTI e feministas alvos de tortura e de morte, tanto quanto reiteraram o Partido dos Trabalhadores como um mal a ser extirpado. [...]

Outros tempos sombrios

A cada dia se demonstra mais claro que o marxismo ortodoxo falhou em prever o fim do capitalismo e que, quando vislumbrou uma comunidade global socialista, não soube reconhecer a potência da individualidade nessa construção. Nada há de tardio nesse sistema do capital que parece tomar novo fôlego depois de cada crise. Em sua forma atual, com sinais fracos das antigas ideologias, nos tornamos simplificados como elementos de dois conjuntos: com dinheiro e sem dinheiro, e isso sem garantia alguma de permanência em um e outro. Trata-se de esmagamento sem precedentes do sujeito/subjetividade que tem-nos levado a perder todo e qualquer parâmetro de pertencimento. Quase já não há conjunções simbólicas que nos contornem, primeiro, como coletividade; segundo, como indivíduos. Massa informe, homogeneizada, ainda que seja através dos discursos de singularidade, somos parte da grande engrenagem de manutenção do sistema no qual cada desejo mais íntimo é transformado em commodities – vide o facebook

Extracts of Leaves of Ficus auriculata Lour.: Antioxidant, Antimicrobial and Phytotoxic Activity

Ficus auriculata Lour. is a tree of the genus Ficus. The aim of this study was to obtain the total phenolic compounds; and to determine the antioxidant (DPPH), antimicrobial (diffusion disc and Minimal Inhibitory Concentration) and phytotoxic activity (in cucumber - Cucumis sativus L.) of the extracts. Five extraction methods were used to obtain extracts of young and mature leaves of F. auriculata: water/ethanol (M1), water/ethanol/ultrasound (M2), water/ethanol/cellulase complex (M3), water (M4) and water/cellulase complex (M5). The phenolic content for extracts of young leaves was of 30.22 ± 2.99 mg GAE.g-1 dry sample (M1), 35.22 ± 0.53 mg GAE.g-1 dry sample (M2) and 28.90 ± 0.57 mg GAE.g-1 dry sample (M3) and for the mature leaves of 24.42 ± 0.04 mg GAE.g-1 dry sample (M2) and 17.13 ± 4.69 mg GAE.g-1 dry sample (M1). For the antioxidant activity, the lowest values of IC50 (or higher antioxidant activity) occurred for the extracts of young and mature leaves obtained by the M2. The extracts were able to inhibit all the evaluated bacteria, presenting MICs in the range of 21.60–90.32 µg.ml-1 for the Escherichia coli, 21.60-188.85 µg.ml-1 for the Salmonella enteritidis, 64.22-188.85 µg.ml-1 for the Staphylococcus aureus and 76.31-87.82 µg.ml-1 for the Listeria monocytogenes. The extracts of young and adult leaves presented herbicide potential, occurring suppression of the growth of cucumber plants. The use of the extract obtained in M3 led to the death of the plants. Extracts of F. auriculata presented antioxidant and antimicrobial activities, which agree with previous studies linking phenolic compounds to these properties

Influences of Nationality and National Identification on Perceived Dangerousness of COVID-19 Variants and Perceived Effectiveness of COVID-19 Vaccines:A Study of UK and Portuguese Samples

During the COVID-19 pandemic, both variants of the virus that causes the disease and vaccines developed to combat it have been identified with nationalities. Both social identity theory and identity process theory would predict that this would initiate intergroup differentiation processes aimed at optimizing ingroup value and personal identity enhancement. Our study examined whether people’s nationality and level of national identification influence their perception of dangerousness of variants and effectiveness of vaccines. We compared data collected by online survey in March 2021 from the UK (which was associated with both a variant and a vaccine) and Portugal (which was associated with neither). The Portuguese rated variants overall as more dangerous than did the UK sample. The Chinese variant was rated by both samples as the least dangerous and the UK sample rated the British variant as less dangerous than did the Portuguese. Higher national identification in the UK sample was associated with differentiating more between the British variant and the South African variant and differentiating it less from the Chinese variant. The UK sample rated the effectiveness of the British vaccine higher than did the Portuguese. They also evaluated it as more effective than the American, Chinese and Indian vaccines. In both samples, higher national identification was associated with lower ratings of effectiveness for vaccines originating in China or India. Our study suggests that identity processes associated with national identification do influence perceptions of vaccines and variants. This has significant practice and policy implications. Social representations of variants and vaccines in nationalistic terms can have complex and unexpected consequences