Arquitectura WDM-PON baseada em componentes sintonizáveis

Mestrado em Engenharia Electrónica e TelecomunicaçõesO tema principal abordado neste trabalho é a tecnologia WDM-PON como próxima geração de redes de acesso. Começou por ser feita uma abordagem geral a este tópico, servindo esta como ponto de partida para a parte experimental. Foi proposta e demonstrada uma arquitectura WDM-PON bidirecional directamente modulada baseada em lasers sintonizáveis e receptores sintonizáveis no terminal do utilizador, e um divisor de potência no nó de acesso. Foram também apontados possíveis melhoramentos ao hardware desta arquitectura. Dois formatos de modulação avançados – QPSK e Duobinário – foram abordados, no contexto dos sistemas WDM-PON. Assim sendo, foram testados um sistema coerente QPSK e um sistema UDWDM-QPSK e foram apresentados os resultados obtidos.The main topic of this work is WDM-PON as a technology for next generation access networks. It was first made a general approach to this topic, serving as starting point to the experimental part. It was proposed and demonstrated a bidirectional directly modulated WDM-PON architecture based on tunable lasers and tunable receivers at the users’ end, and a splitter at the Remote Node. Possible improvements to this architecture’s hardware were also pointed out. Two advanced modulation formats – QPSK and Duobinary – were addressed, in the context of WDM-PON systems. Thus, we tested a coherent QPSK and a UDWDM QPSK system and present the obtained results

Promotion of Education in Geosciences and UNESCO Global Geoparks

Considering that Earth is an active planet and that anthropic action contributes to alter the planet's dynamic equilibrium, through the increase of the natural hazards and depletion or destruction of the geological heritage, often for lack of knowledge of its scientific and didactic value, the dissemination of the work developed in Geosciences as well as Education, is of the utmost importance. In this context, the dissemination and teaching of Geosciences gained another dynamic with the creation of Geoparks because, these geographically well-defined territories that possess a remarkable geological heritage, in association with the other elements of the natural and cultural heritage, have as fundamental pillars Geoconservation, Tourism and Education for Sustainability. In this context, the UNESCO Global Geoparks promote the development of educational programs and interpretive resources, contributing to the dissemination of scientific knowledge enabling a greater visibility to Geosciences among the educational community and the general public. The Estrela Aspiring Geopark, which has an area of approximately 2216 km2 and includes 9 municipalities around Estrela, is a territory where sustainable development is sought in an integrated way, based on its geological and geomorphological heritage, of national and international relevance, its biodiversity and its culture, a reflection of the secular adaptation of its communities to this mountain territory. Here we can find important marks of the last glaciation that occurred about 30,000 years ago. This aspiring UNESCO Global Geopark is promoting multidisciplinary educational programs, which include indoor and outdoor activities, aimed at different levels of education (Basic, Secondary and Higher Education), in order to foster direct contact with the geological heritage, thus contributing to the recognition of its importance and consequently to the need for its conservation, since it is only possible to value and preserve what is truly known. The Estrela Aspiring Geopark has also interpretive routes in the field of non-formal education, aimed at the general public, and thus contributing to the dissemination and preservation of the valuable natural and cultural heritage of Estrela, as well as its use in a sustainable way. This article intends to demonstrate the importance of education in the dissemination of scientific knowledge, especially in the field of Geosciences, and to reveal how UNESCO Global Geoparks can be living laboratories, where multiple didactic and learning experiences are developed.info:eu-repo/semantics/publishedVersio

Tourism as a Link between Estrela Geopark and Serra da Estrela Natural Park

To look at the Estrela Geopark territory is to find a mosaic of huge natural and cultural values as well as a unique scenic beauty, factors that contribute to its tourist attractiveness. As such, a synchronous work by local agents is required, making best use of these values and actively contributing to the sustainable development of populations, a strategy that can be supported by the patrimonialisation of existing Estrela`s resources. Regarding tourism as an economic activity and social phenomenon, it functions as an agent for development, especially in regions where the economy is not very competitive, as is the case of rural areas in mainland Portugal. Based on this, it`s possible to identify two entities with a very important role in the future of the region of Serra da Estrela. The Institute for Conservation of Nature and Forests (ICNF), which is responsible for the protected area corresponding to the Serra da Estrela Natural Park (SENP), and the Associação Geopark Estrela (AGE), responsible for the UNESCO Global Geopark application. As such, the existence of common objectives for heritage conservation and valorisation allow a complementary work by these entities. On the one hand, through its laws and directives, the existence of a protected area (SENP) in the territory of the Geopark allows the more effective conservation of this heritage. On the other hand, the Geopark can add to its greater valorisation and interpretation, contributing to the populations` involvement in the conservation process, something that has sometimes been difficult for the SENP. The focus on nature tourism has increasingly been one of the focuses of both entities, with the realization of interpreted routes, educational programs, as well as the installation of interpretive infrastructures being examples that intend to constructively raise the awareness of resident populations and tourists who visit this territory. In addition to these, during this year, this partnership will also result in the organization of the ObservaEstrela. Coordinated by the AGE, this event will be part of the “Observa” network promoted by ICNF, and will consist of a nature tourism fair, with lectures and workshops, shows, and field trips with observation and interpretation of biotic and abiotic heritage. The objective is to promote, in an integrated way, the relationship between science and tourism, further strengthening this partnership between these two entities and valuing a territory that has long deserved an event of this nature. Based on these experiences, the objective will be to demonstrate how tourism can strengthen this link between the Estrela Geopark and the Serra da Estrela Natural Park, working common vertices together that allow the implementation of a sustainable development strategy, and thus, helping the populations of this territory for which this future UNESCO Global Geopark classification is intended.info:eu-repo/semantics/publishedVersio

EFAS-Meteo: A European daily high-resolution gridded meteorological data set for 1990 - 2011

Data sets of spatially irregular meteorological observations interpolated to a regular grid are not only important for climate analyses but are also essential in order to derive climatologies for rainfall-runoff models which require meteorological data sets as input forcing. For example, in the European Flood Awareness System long term observed meteorological data are used to drive the hydrological model LISFLOOD to obtain long term time series of simulated discharges at a pan-European scale. Those long term time series of simulated “proxy” discharges can then be used for statistical analysis, e.g., to derive return periods or other time series derivatives. In this report, we present a comprehensive pan European high-resolution gridded daily data set (EFAS-Meteo) of precipitation, surface temperature (mean, minimum and maximum), wind speed, vapour pressure, calculated radiation and evapotranspiration (potential evapotranspiration, bare soil and open water evapotranspiration). The data set was created as part of the development of EFAS and has been continuously updated throughout the last years.JRC.H.7-Climate Risk Managemen

Estudo hidrogeológico de uma área montanhosa (Serra da Estrela,Portugal central): uma abordagem multidisciplinar

The results ofa preliminary hydrogeological study ofthe river Zêzere catchment upstream ofManteigas(Serra da Estrela Natural Park,Central Portugal) are presented.In this mountain region,different types of groundwater and surface water (used in several economic activities) occur.The methodology adopted in thisstudy emphasizes the way how Geology,Geomorphology,Geophysics,Geochemistry,Soil Science andHydrogeology contribute to the description ofthe hydrological phenomena taking place in the catchment,such as infiltration and aquifer recharge and groundwater flow and geochemistry — allowing to develop bet-ter hydrogeologic conceptual models.The hydrological modelling in course includes the use ofthe VISU- AL BALAN code,which is being coupled to a GIS.The hydrogeochemical techniques are highlighted as well as its preliminary results concerning major and minor elements.The thermomineral water study includes the identification ofthe reservoir’s geologic material,the characterization ofwater-rock interactionand geothermometry.info:eu-repo/semantics/publishedVersio

Measurement of the cross section for the production of a WW boson in association with b−b^- jets in pppp collisions at s=7\sqrt{s}=7 TeV with the ATLAS detector

A measurement is presented of the cross section for the production of a W boson with one or two jets, of which at least one must be a b-jet, in pp collisions at sqrt(s)=7 TeV. Production via top decay is not included in the signal definition. The measurement is based on 35 pb^-1 of data collected with the ATLAS detector at the LHC. The W+b-jet cross section is defined for jets reconstructed with the anti-kt clustering algorithm with transverse momentum above 25 GeV and rapidity within +/-2.1. The b-jets are identified by reconstructing secondary vertices. The fiducial cross section is measured both for the electron and muon decay channel of the W boson and is found to be 10.2 +/- 1.9 (stat) +/- 2.6 (syst) pb for one lepton flavour. The results are compared with next-to-leading order QCD calculations, which predict a cross section smaller than, though consistent with, the measured value.Peer Reviewe

Search for New Physics in the Dijet Mass Distribution using 1 fb−1^{-1} of pppp Collision Data at s=\sqrt{s}=7 TeV collected by the ATLAS Detector

Invariant mass distributions of jet pairs (dijets) produced in LHC proton-proton collisions at a centre-of-mass energy sqrt(s)=7 TeV have been studied using a data set corresponding to an integrated luminosity of 1.0 fb^-1 recorded in 2011 by ATLAS. Dijet masses up to ~4 TeV are observed in the data, and no evidence of resonance production over background is found. Limits are set at 95% CL for several new physics hypotheses: excited quarks are excluded for masses below 2.99 TeV, axigluons are excluded for masses below 3.32 TeV, and colour octet scalar resonances are excluded for masses below 1.92 TeV.Peer Reviewe

Measurement of the top quark pair production cross section in pppp collisions at s=7\sqrt{s}=7 TeV in dilepton final states with ATLAS

A measurement of the production cross section of top quark pairs (ttbar) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider is reported. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. Using a data sample corresponding to an integrated luminosity of 35 pb^-1, a ttbar production cross section of 171 +/- 20(stat.) +/- 14(syst.) +8-6(lum.) pb is measured for an assumed top quark mass of 172.5 GeV. A second measurement requiring at least one jet identified as coming from a b quark yields a comparable result, demonstrating that the dilepton final states are consistent with being accompanied by b-quark jets. These measurements are in good agreement with Standard Model predictions.Peer Reviewe

Performance of Missing Transverse Momentum Reconstruction in Proton-Proton Collisions at 7 TeV with ATLAS

The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and events with jets of hadrons are used from data samples corresponding to an integrated luminosity of about 0.3 inverse nb and 600 inverse nb, together with events containing a Z boson decaying to two leptons (electrons or muons) or a W boson decaying to a lepton (electron or muon) and a neutrino, from a data sample corresponding to an integrated luminosity of about 36 inverse pb. An estimate of the systematic uncertainty on the missing transverse momentum scale is presented.Peer Reviewe

Measurement of photon–jet transverse momentum correlations in 5.02 TeV Pb + Pb and pppp collisions with ATLAS

Jets created in association with a photon can be used as a calibrated probe to study energy loss in the medium created in nuclear collisions. Measurements of the transverse momentum balance between isolated photons and inclusive jets are presented using integrated luminosities of 0.49 nb$^{-1}$ of Pb+Pb collision data at $\sqrt{s_\mathrm{NN}}=5.02$ TeV and 25 pb$^{-1}$ of $pp$ collision data at $\sqrt{s}=5.02$ TeV recorded with the ATLAS detector at the LHC. Photons with transverse momentum $63.1 31.6$ GeV and pseudorapidity $\left|\eta^\mathrm{jet}\right| 7\pi/8$. Distributions of the per-photon jet yield as a function of $x_\mathrm{J\gamma}$, $(1/N_\gamma)(\mathrm{d}N/\mathrm{d}x_\mathrm{J\gamma})$, are corrected for detector effects via a two-dimensional unfolding procedure and reported at the particle level. In $pp$ collisions, the distributions are well described by Monte Carlo event generators. In Pb+Pb collisions, the $x_\mathrm{J\gamma}$ distribution is modified from that observed in $pp$ collisions with increasing centrality, consistent with the picture of parton energy loss in the hot nuclear medium. The data are compared with a suite of energy-loss models and calculations.Peer Reviewe