507 research outputs found

    Network slicing architecture for SDM and analog-radio-over-fiber-based 5G fronthaul networks

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    \u3cp\u3eThe blueSPACE project focuses on the study of innovative technologies to overcome the limitations of current fronthaul networks. The key technology proposed is space-division multiplexing, which makes it possible to increase the capacity available in conventional single-mode fibers, effectively encompassing this capacity to the forecasted bandwidth demands imposed by 5G mobile communications. In this paper, we present the innovative optical fronthaul infrastructure proposed in the project and the tailored extensions to the European Telecommunications Standards Institute network function virtualization management and orchestration architecture for this enhanced infrastructure together with practical implementation considerations.\u3c/p\u3

    Analysis of the IBM CCA Security API Protocols in Maude-NPA

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    Standards for cryptographic protocols have long been attractive candidates for formal verification. It is important that such standards be correct, and cryptographic protocols are tricky to design and subject to non-intuitive attacks even when the underlying cryptosystems are secure. Thus a number of general-purpose cryptographic protocol analysis tools have been developed and applied to protocol standards. However, there is one class of standards, security application programming interfaces (security APIs), to which few of these tools have been applied. Instead, most work has concentrated on developing special-purpose tools and algorithms for specific classes of security APIs. However, there can be much advantage gained from having general-purpose tools that could be applied to a wide class of problems, including security APIs. One particular class of APIs that has proven difficult to analyze using general-purpose tools is that involving exclusive-or. In this paper we analyze the IBM 4758 Common Cryptographic Architecture (CCA) protocol using an advanced automated protocol verification tool with full exclusive-or capabilities, the Maude-NPA tool. This is the first time that API protocols have been satisfactorily specified and analyzed in the Maude-NPA, and the first time XOR-based APIs have been specified and analyzed using a general-purpose unbounded session cryptographic protocol verification tool that provides direct support for AC theories. We describe our results and indicate what further research needs to be done to make such protocol analysis generally effective.Antonio González-Burgueño, Sonia Santiago and Santiago Escobar have been partially supported by the EU (FEDER) and the Spanish MINECO under grants TIN 2010-21062-C02-02 and TIN 2013-45732-C4-1-P, and by Generalitat Valenciana PROMETEO2011/052. José Meseguer has been partially supported by NSF Grant CNS 13-10109.González Burgueño, A.; Santiago Pinazo, S.; Escobar Román, S.; Meadows, C.; Meseguer, J. (2014). Analysis of the IBM CCA Security API Protocols in Maude-NPA. En Security Standardisation Research. Springer International Publishing. 111-130. https://doi.org/10.1007/978-3-319-14054-4_8S111130Abadi, M., Blanchet, B., Fournet, C.: Just fast keying in the pi calculus. ACM Trans. Inf. Syst. Secur. 10(3) (2007)Blanchet, B.: An Efficient Cryptographic Protocol Verifier Based on Prolog Rules. In: 14th IEEE Computer Security Foundations Workshop (CSFW 2014), Cape Breton, Nova Scotia, Canada, June 2001, pp. 82–96. IEEE Computer Society (2014)Bond, M.: Attacks on cryptoprocessor transaction sets. In: Koç, Ç.K., Naccache, D., Paar, C. (eds.) CHES 2001. LNCS, vol. 2162, pp. 220–234. Springer, Heidelberg (2001)Butler, F., Cervesato, I., Jaggard, A.D., Scedrov, A.: A formal analysis of some properties of kerberos 5 using msr. In: CSFW, pp. 175–1790. IEEE Computer Society (2002)Cachin, C., Chandran, N.: A secure cryptographic token interface. In: Proceedings of the 22nd IEEE Computer Security Foundations Symposium, CSF 2009, Port Jefferson, New York, USA, July 8-10, pp. 141–153 (2009)Chevalier, Y., Küsters, R., Rusinowitch, M., Turuani, M.: An NP decision procedure for protocol insecurity with XOR. In: 18th Annual IEEE Symposium on Logic in Computer Science, LICS 2003 (2003)Comon-Lundh, H., Shmatikov, V.: Intruder deductions, constraint solving and insecurity decision in presence of exclusive-or. In: 18th Annual IEEE Symposium on Logic in Computer Science (LICS 2003), pp. 271–280 (2003)Comon-Lundh, H., Cortier, V.: New decidability results for fragments of first-order logic and application to cryptographic protocols. In: Nieuwenhuis, R. (ed.) RTA 2003. LNCS, vol. 2706, pp. 148–164. Springer, Heidelberg (2003)Cortier, V., Keighren, G., Steel, G.: Automatic analysis of the aecurity of XOR-based key management schemes. In: Grumberg, O., Huth, M. (eds.) TACAS 2007. LNCS, vol. 4424, pp. 538–552. Springer, Heidelberg (2007)Cortier, V., Steel, G.: A generic security API for symmetric key management on cryptographic devices. In: Backes, M., Ning, P. (eds.) ESORICS 2009. LNCS, vol. 5789, pp. 605–620. Springer, Heidelberg (2009)Erbatur, S., et al.: Effective Symbolic Protocol Analysis via Equational Irreducibility Conditions. In: Foresti, S., Yung, M., Martinelli, F. (eds.) ESORICS 2012. LNCS, vol. 7459, pp. 73–90. Springer, Heidelberg (2012)Escobar, S., Meadows, C., Meseguer, J.: Maude-NPA: Cryptographic Protocol Analysis Modulo Equational Properties. In: Aldini, A., Barthe, G., Gorrieri, R. (eds.) FOSAD 2007/2008/2009. LNCS, vol. 5705, pp. 1–50. Springer, Heidelberg (2007)Escobar, S., Meadows, C., Meseguer, J., Santiago, S.: Sequential Protocol Composition in Maude-NPA. In: Gritzalis, D., Preneel, B., Theoharidou, M. (eds.) ESORICS 2010. LNCS, vol. 6345, pp. 303–318. Springer, Heidelberg (2010)Thayer Fabrega, F.J., Herzog, J., Guttman, J.: Strand Spaces: What Makes a Security Protocol Correct? Journal of Computer Security 7, 191–230 (1999)González-Burgueño, A.: Protocol Analysis Modulo Exclusive-Or Theories: A Case study in Maude-NPA. Master’s thesis, Universitat Politècnica de València (March 2014), https://angonbur.webs.upv.es/Previous_work/Master_Thesis.pdfIBM. Comment on Mike’s Bond paper A Chosen Key Difference Attack on Control Vectors (2001), http://www.cl.cam.ac.uk/~mkb23/research/CVDif-Response.pdfIBM. CCA basic services reference and guide: CCA basic services reference and guide for the IBM 4758 PCI and IBM 4764 (2001), http://www-03.ibm.com/security/cryptocards/pdfs/bs327.pdf.2008Keighren, G.: Model Checking IBM’s Common Cryptographic Architecture API. Technical Report 862, University of Edinburgh (October 2006)Kemmerer, R.A.: Using formal verification techniques to analyze encryption protocols. In: IEEE Symposium on Security and Privacy, pp. 134–139. IEEE Computer Society (1987)Küsters, R., Truderung, T.: Reducing protocol analysis with xor to the xor-free case in the horn theory based approach. J. Autom. Reasoning 46(3-4), 325–352 (2011)Linn, J.: Generic security service application program interface version 2, update 1. IETF RFC 2743 (2000), https://datatracker.ietf.org/doc/rfc2743Longley, D., Rigby, S.: An automatic search for security flaws in key management schemes. Computers & Security 11(1), 75–89 (1992)Meadows, C.: Applying formal methods to the analysis of a key management protocol. Journal of Computer Security 1(1) (1992)Meadows, C.: The NRL protocol analyzer: An overview. Journal of Logic Programming 26(2), 113–131 (1996)Meadows, C., Cervesato, I., Syverson, P.: Specification and Analysis of the Group Domain of Interpretation Protocol using NPATRL and the NRL Protocol Analyzer. Journal of Computer Security 12(6), 893–932 (2004)Meadows, C.: Analysis of the internet key exchange protocol using the nrl protocol analyzer. In: IEEE Symposium on Security and Privacy, pp. 216–231. IEEE Computer Society (1999)Meier, S., Schmidt, B., Cremers, C., Basin, D.: The TAMARIN prover for the symbolic snalysis of security protocols. In: Sharygina, N., Veith, H. (eds.) CAV 2013. LNCS, vol. 8044, pp. 696–701. Springer, Heidelberg (2013)Mukhamedov, A., Gordon, A.D., Ryan, M.: Towards a verified reference implementation of a trusted platform module. In: Christianson, B., Malcolm, J.A., Matyáš, V., Roe, M. (eds.) Security Protocols 2009. LNCS, vol. 7028, pp. 69–81. Springer, Heidelberg (2013)National Institute of Standards and Technology. FIPS PUB 46-3: Data Encryption Standard (DES), supersedes FIPS 46-2 (October 1999)Nieuwenhuis, R. (ed.): CADE 2005. LNCS (LNAI), vol. 3632. Springer, Heidelberg (2005)Steel, G.: Deduction with xor constraints in security api modelling. In: Nieuwenhuis (ed.) [30], pp. 322–336Verma, K.N., Seidl, H., Schwentick, T.: On the complexity of equational horn clauses. In: Nieuwenhuis (ed.) [30], pp. 337–35

    The ac magnetic response of mesoscopic type II superconductors

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    The response of mesoscopic superconductors to an ac magnetic field is numerically investigated on the basis of the time-dependent Ginzburg-Landau equations (TDGL). We study the dependence with frequency ω\omega and dc magnetic field HdcH_{dc} of the linear ac susceptibility χ(Hdc,ω)\chi(H_{dc}, \omega) in square samples with dimensions of the order of the London penetration depth. At Hdc=0H_{dc}=0 the behavior of χ\chi as a function of ω\omega agrees very well with the two fluid model, and the imaginary part of the ac susceptibility, χ"(ω)\chi"(\omega), shows a dissipative a maximum at the frequency νo=c2/(4πσλ2)\nu_o=c^2/(4\pi \sigma\lambda^2). In the presence of a magnetic field a second dissipation maximum appears at a frequency ωpν0\omega_p\ll\nu_0. The most interesting behavior of mesoscopic superconductors can be observed in the χ(Hdc)\chi(H_{dc}) curves obtained at a fixed frequency. At a fixed number of vortices, χ"(Hdc)\chi"(H_{dc}) continuously increases with increasing HdcH_{dc}. We observe that the dissipation reaches a maximum for magnetic fields right below the vortex penetration fields. Then, after each vortex penetration event, there is a sudden suppression of the ac losses, showing discontinuities in χ"(Hdc)\chi"(H_{dc}) at several values of HdcH_{dc}. We show that these discontinuities are typical of the mesoscopic scale and disappear in macroscopic samples, which have a continuos behavior of χ(Hdc)\chi(H_{dc}). We argue that these discontinuities in χ(Hdc)\chi(H_{dc}) are due to the effect of {\it nascent vortices} which cause a large variation of the amplitude of the order parameter near the surface before the entrance of vortices.Comment: 12 pages, 9 figures, RevTex

    On the Filter Narrowing Issues in Elastic Optical Networks

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    This paper describes the problematic filter narrowing effect in the context of next-generation elastic optical networks. First, three possible scenarios are introduced: the transition from an actual fixed-grid to a flexigrid network, the generic full flexi-grid network, and a proposal for a filterless optical network. Next, we investigate different transmission techniques and evaluate the penalty introduced by the filtering effect when considering Nyquist wavelength division multiplexing, single side-band direct-detection orthogonal frequency division multiplexing, and symbol-rate variable dual polarization quadrature amplitude modulation. Also, different approaches to compensate for the filter narrowing effect are discussed. Results show that the specific needs per each scenario can be fulfilled by the aforementioned technologies and techniques or a combination of them, when balancing performance, network reach, and cost

    An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

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    Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles

    NMR and NQR Fluctuation Effects in Layered Superconductors

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    We study the effect of thermal fluctuations of the s-wave order parameter of a quasi two dimensional superconductor on the nuclear spin relaxation rate near the transition temperature Tc. We consider both the effects of the amplitude fluctuations and the Berezinskii-Kosterlitz-Thouless (BKT) phase fluctuations in weakly coupled layered superconductors. In the treatment of the amplitude fluctuations we employ the Gaussian approximation and evaluate the longitudinal relaxation rate 1/T1 for a clean s-wave superconductor, with and without pair breaking effects, using the static pair fluctuation propagator D. The increase in 1/T1 due to pair breaking in D is overcompensated by the decrease arising from the single particle Green's functions. The result is a strong effect on 1/T1 for even a small amount of pair breaking. The phase fluctuations are described in terms of dynamical BKT excitations in the form of pancake vortex-antivortex (VA) pairs. We calculate the effect of the magnetic field fluctuations caused by the translational motion of VA excitations on 1/T1 and on the transverse relaxation rate 1/T2 on both sides of the BKT transitation temperature T(BKT)<Tc. The results for the NQR relaxation rates depend strongly on the diffusion constant that governs the motion of free and bound vortices as well as the annihilation of VA pairs. We discuss the relaxation rates for real multilayer systems where the diffusion constant can be small and thus increase the lifetime of a VA pair, leading to an enhancement of the rates. We also discuss in some detail the experimental feasibility of observing the effects of amplitude fluctuations in layered s-wave superconductors such as the dichalcogenides and the effects of phase fluctuations in s- or d-wave superconductors such as the layered cuprates.Comment: 38 pages, 12 figure

    Depression among women living in the outskirts of São Paulo, Southeastern Brasil

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    OBJECTIVE: To assess the meaning of depression in women diagnosed with the disorder, and the context of care given by the psychiatrists who follow them up. METHODS: Qualitative study performed in Embu, outskirt of São Paulo, between August 2002 and January 2003. Etnographic observation and in-depth interview were carried out with 16 women diagnosed with depression in primary care, and four psychiatrists. After exhaustive reading, data were grouped into categories and assessed. The assessment of outcomes was based on the concept of culture. RESULTS: Women interviewed are well aware of the disorder, and accept treatment based on medication. For psychiatrists, depression is a term understood by the common sense. All women interviewed identified the onset of the disease from a past event such as: death of a son, violent episodes connected with drug traffic, unemployment, and partners' aggressiveness. Violence was common in the every day life of the interviewed women both inside and outside their homes. CONCLUSIONS: For these women, depression is a way to express their feelings, such as unhappiness in a context of poverty and violence. Psychiatrists go beyond their clinical functions and play an important role on reorganizing the daily life of these women.OBJETIVO: Analisar o significado da depressão para mulheres diagnosticadas com o transtorno e o contexto do atendimento realizado pelos psiquiatras que as acompanham. MÉTODOS: Estudo qualitativo realizado no município de Embu, na Grande São Paulo, entre agosto de 2002 e janeiro de 2003. Foram realizadas observação etnográfica e entrevistas em profundidade com 16 mulheres diagnosticadas com depressão, pacientes de uma Unidade Básica de Saúde, e quatro psiquiatras. Após a leitura exaustiva, os dados foram agrupados em categorias e analisados. A interpretação dos resultados baseou-se no conceito de cultura. RESULTADOS: As entrevistadas tinham ampla noção do transtorno, aceitando o tratamento com medicação. Para os psiquiatras, a depressão é um termo assimilado pelo senso-comum. Todas as entrevistadas identificaram a origem da doença em eventos passados, como: morte de filho, episódios violentos ligados ao tráfico de drogas, desemprego e agressividade do companheiro. A violência era comum no cotidiano das entrevistadas, tanto fora como dentro de casa. CONCLUSÕES: Para essas mulheres, a depressão era uma forma de expressar sentimentos, como a infelicidade num contexto de pobreza e violência. Os psiquiatras extrapolam as suas funções clínicas e têm um papel na reorganização do cotidiano dessas mulheres.Universidade Católica de Santos Programa de Mestrado em Saúde ColetivaUniversidade Federal de São Paulo (UNIFESP) Departamento de PsiquiatriaUNIFESP, Depto. de PsiquiatriaSciEL

    Nanotechnology applied to European food production – A review of ethical and regulatory issues

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    Various ethical issues are associated with agrifood nanotechnology, linked to the ethical concepts of autonomy, beneficence, non-malfeasance and justice (ensuring safety, effective risk assessment, transparency, consumer benefits and choice, animal welfare and environmental protection). Nanotechnology applications are currently covered by legislative instruments originally designed for other purposes. Risk assessment procedures are in most cases not specific to (agrifood) nano-materials, resulting in uncertainty regarding the nature and extent of potential risks. There are currently no requirements for nano-materials used in agrifood production to be labelled. Ethical principles, and societal acceptance require labelling of food products that are produced using nanotechnology

    Molecular mechanisms of toxicity of silver nanoparticles in zebrafish embryos.

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    addresses: Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK. [email protected]: Journal Article; Research Support, Non-U.S. Gov'tThis is an open access article that is freely available in ORE or from the publisher's web site. http://pubs.acs.org/doi/abs/10.1021/es401758d. Please cite the published version© 2013 American Chemical SocietySupporting Information: Further details on the methodology and results for the characterization of the silver particles used for the exposures, mortality curves, sequencing analysis, and a number of supporting figures and tables. This material is available free of charge via the Internet at http://pubs.acs.org.Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk-, and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24 h of exposure, but with a recovery at 48 h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24 h, but not at 48 h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms.Natural Environment Research Council (NERC)NERC Biomolecular Analysis FacilityUK Environment AgencySystems Biology Seed fund, University of Exete
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