914 resultados para video-on-demand


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Presented at IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2015). 19 to 21, Aug, 2015.

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The increasing number of television channels, on-demand services and online content, is expected to contribute to a better quality of experience for a costumer of such a service. However, the lack of efficient methods for finding the right content, adapted to personal interests, may lead to a progressive loss of clients. In such a scenario, recommendation systems are seen as a tool that can fill this gap and contribute to the loyalty of users. Multimedia content, namely films and television programmes are usually described using a set of metadata elements that include the title, a genre, the date of production, and the list of directors and actors. This paper provides a deep study on how the use of different metadata elements can contribute to increase the quality of the recommendations suggested. The analysis is conducted using Netflix and Movielens datasets and aspects such as the granularity of the descriptions, the accuracy metric used and the sparsity of the data are taken into account. Comparisons with collaborative approaches are also presented.

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Cloud computing has been one of the most important topics in Information Technology which aims to assure scalable and reliable on-demand services over the Internet. The expansion of the application scope of cloud services would require cooperation between clouds from different providers that have heterogeneous functionalities. This collaboration between different cloud vendors can provide better Quality of Services (QoS) at the lower price. However, current cloud systems have been developed without concerns of seamless cloud interconnection, and actually they do not support intercloud interoperability to enable collaboration between cloud service providers. Hence, the PhD work is motivated to address interoperability issue between cloud providers as a challenging research objective. This thesis proposes a new framework which supports inter-cloud interoperability in a heterogeneous computing resource cloud environment with the goal of dispatching the workload to the most effective clouds available at runtime. Analysing different methodologies that have been applied to resolve various problem scenarios related to interoperability lead us to exploit Model Driven Architecture (MDA) and Service Oriented Architecture (SOA) methods as appropriate approaches for our inter-cloud framework. Moreover, since distributing the operations in a cloud-based environment is a nondeterministic polynomial time (NP-complete) problem, a Genetic Algorithm (GA) based job scheduler proposed as a part of interoperability framework, offering workload migration with the best performance at the least cost. A new Agent Based Simulation (ABS) approach is proposed to model the inter-cloud environment with three types of agents: Cloud Subscriber agent, Cloud Provider agent, and Job agent. The ABS model is proposed to evaluate the proposed framework.

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Series: "Advances in intelligent systems and computing , ISSN 2194-5357, vol. 417"

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Tese de Doutoramento Ciência e Engenharia de Polímeros e Compósitos.

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We investigate the spontaneous emission rate of a two-level quantum emitter near a graphene-coated substrate under the influence of an external magnetic field or strain induced pseudo-magnetic field. We demonstrate that the application of the magnetic field can substantially increase or decrease the decay rate. We show that a suppression as large as 99$\%$ in the Purcell factor is achieved even for moderate magnetic fields. The emitter's lifetime is a discontinuous function of $|{\bf B}|$, which is a direct consequence of the occurrence of discrete Landau levels in graphene. We demonstrate that, in the near-field regime, the magnetic field enables an unprecedented control of the decay pathways into which the photon/polariton can be emitted. Our findings strongly suggest that a magnetic field could act as an efficient agent for on-demand, active control of light-matter interactions in graphene at the quantum level.

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Programa Doutoral em Líderes para as Indústrias Tecnológicas

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Aquest projecte consisteix en la implementació d'una migració d'agents mòbils amb sol·licitud de classes sota demanda de manera segura per a la plataforma JADE. En aquest projecte hem desenvolupat dos protocols de control d'accés i autentificació sobre agents i/o plataformes. Però la línia central de desenvolupament d'aquest projecte radica en la creació d'un protocol de migració sota demanda d'agents. Hem implementat dues versions d'aquest protocol. La primera versió del protocol de migració es centra en la sol·licitud de classes sota demanda i la segona versió, per tal de millorar-ne el rendiment de la primera, emmagatzema les classes que ha demanat sota demanada en una cache de la plataforma.

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There have been numerous attempts to assess the overall impact of Higher Education Institutions on regional economies in the UK and elsewhere. There are two disparate approaches focussing on: demand-side effects of HEIs, exerted through universities’ expenditures within the local economy; HEIs’ contribution to the “knowledge economy”. However, neither approach seeks to measure the impact on regional economies that HEIs exert through the enhanced productivity of their graduates. We address this lacuna and explore the system-wide impact of the graduates on the regional economy. An extensive and sophisticated literature suggests that graduates enjoy a significant wage premium, often interpreted as reflecting their greater productivity relative to non-graduates. If this is so there is a clear and direct supply-side impact of HEI activities on regional economies through the employment of their graduates. However, there is some dispute over the extent to which the graduate wage premium reflects innate abilities rather than the impact of higher education per se. We use an HEI-disaggregated computable general equilibrium model of Scotland to estimate the impact of the growing proportion of graduates in the Scottish labour force that is implied by the current participation rate and demographic change, taking the graduate wage premium in Scotland as an indicator of productivity enhancement. We conduct a range of sensitivity analyses to assess the robustness of our results. While the detailed results do, of course, vary with alternative assumptions about future graduate retention rates and the size of the graduate wage premium, for example, they do suggest that the long-term supply-side impacts of HEIs provide a significant boost to regional GDP. Furthermore, the results suggest that the supply-side impacts of HEIs are likely to be more important than the expenditure impacts that are the focus of most “impact” studies.

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AbstractDigitalization gives to the Internet the power by allowing several virtual representations of reality, including that of identity. We leave an increasingly digital footprint in cyberspace and this situation puts our identity at high risks. Privacy is a right and fundamental social value that could play a key role as a medium to secure digital identities. Identity functionality is increasingly delivered as sets of services, rather than monolithic applications. So, an identity layer in which identity and privacy management services are loosely coupled, publicly hosted and available to on-demand calls could be more realistic and an acceptable situation. Identity and privacy should be interoperable and distributed through the adoption of service-orientation and implementation based on open standards (technical interoperability). Ihe objective of this project is to provide a way to implement interoperable user-centric digital identity-related privacy to respond to the need of distributed nature of federated identity systems. It is recognized that technical initiatives, emerging standards and protocols are not enough to guarantee resolution for the concerns surrounding a multi-facets and complex issue of identity and privacy. For this reason they should be apprehended within a global perspective through an integrated and a multidisciplinary approach. The approach dictates that privacy law, policies, regulations and technologies are to be crafted together from the start, rather than attaching it to digital identity after the fact. Thus, we draw Digital Identity-Related Privacy (DigldeRP) requirements from global, domestic and business-specific privacy policies. The requirements take shape of business interoperability. We suggest a layered implementation framework (DigldeRP framework) in accordance to model-driven architecture (MDA) approach that would help organizations' security team to turn business interoperability into technical interoperability in the form of a set of services that could accommodate Service-Oriented Architecture (SOA): Privacy-as-a-set-of- services (PaaSS) system. DigldeRP Framework will serve as a basis for vital understanding between business management and technical managers on digital identity related privacy initiatives. The layered DigldeRP framework presents five practical layers as an ordered sequence as a basis of DigldeRP project roadmap, however, in practice, there is an iterative process to assure that each layer supports effectively and enforces requirements of the adjacent ones. Each layer is composed by a set of blocks, which determine a roadmap that security team could follow to successfully implement PaaSS. Several blocks' descriptions are based on OMG SoaML modeling language and BPMN processes description. We identified, designed and implemented seven services that form PaaSS and described their consumption. PaaSS Java QEE project), WSDL, and XSD codes are given and explained.

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Introduction: today, cultural changes may have changed the usual pattern of the mother as the accompanying person in the pediatric office. Objetives: descriptive analysis of the current situation in the pediatrics office. Material and methods: Las Delicias Health Center (health district of Malaga). Selected sample of 250 patients between the periods 1-15 July and 15-30 September, 2011. Results: in most cases (54.8%), the mother stands as the main accompanying person, appearing both parents in the consultation in 16.4% of cases. The figure of the grandparents is of special significance when the mother is an active worker. Most consultations were on-demand by appointment (82.4%), for acute symptoms, with symptoms lasting less than 3 days in most cases (59.2%). Discussion: the mother is presented as the main accompanying person in most cases. The father or grandparents will be present in front of social-cultural factors, mainly active employment status of the mother.

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Objective: to determine the incidence of hand washing in parents as a preventive factor in the spread of viral respiratory infections in children under two years assigned to an urban pediatric basic health area affected by catarrhal symptoms during the influenza vaccination campaign. Material and methods: from 230 children under two years included in the basic health area attending the Well Child program, 51 consulted during the influenza vaccination campaign (October 2011) by catarrhal symptoms. Results: fifty-one children were included, 23 male and 28 female. From the clinical point of view, 33 cases were afebrile and only 18 had fever, runny nose 100%. The clinic diagnosis in 44 cases was nasopharyngitis, acute bronchitis in 5 cases and obstructive bronchiolitis in 2 cases. No family history in 19, however 32 cases had a family member with catarrhal symptoms. As for the performance of hand washing as a preventive measure, 34 cases said they did not comply with this measure, only 17 cases did, despite the recommendations. Conclusions: while recognizing the importance of hand washing as a preventive measure for respiratory infections and being included among the recommendations offered in the well child program, only 33% of the population of our study reported washing hands. This recommendation should also be included in consultations on demand during the influenza season to encourage compliance.

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Pharmacological treatment of patients with stable COPD should be individualised. Inhaled bronchodilators are the mainstay of pharmacological treatment for COPD. Long-acting medications (LABA or LAMA) are recommended over short-acting agents (SABA or SAMA). Short-acting bronchodilators are used on demand to rapidly control symptoms regardless of level of severity. Long-acting bronchodilators are used as maintenance therapy and are the mainstay of treatment in patients with permanent symptoms. Initial treatment for COPD is monotherapy with a long-acting bronchodilator. Clinical practice guidelines do not specify the best bronchodilator to use. The choice should be made on an individual basis, taking into account the patient’s preferences, response to treatment, its potential side effects and cost. When monotherapy fails to control symptoms, the first recommended step is to check medication adherence, inhaler technique and adequacy of inhalation device, and if these are correct but monotherapy is still insufficient, treatment should be intensified with combined inhaled therapies. Most clinical practice guidelines recommend the use of long-term therapy with LABA+inhaled corticosteroids in patients who experience frequent exacerbations and with FEV1 <50%. Long-term monotherapy with inhaled corticosteroids or oral corticosteroids is not recommended, and neither is the regular use of mucolytics nor the use of roflumilast.

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Mapping the human auditory cortex with standard functional imaging techniques is difficult because of its small size and angular position along the Sylvian fissure. As a result, the exact number and location of auditory cortex areas in the human remains unknown. In a first experiment, we measured the two largest tonotopic areas of primary auditory cortex (PAC, Al and R) using high-resolution functional MRI at 7 Tesla relative to the underlying anatomy of Heschl's gyrus (HG). The data reveals a clear anatomical- functional relationship that indicates the location of PAC across the range of common morphological variants of HG (single gyri, partial duplication and complete duplication). Human PAC tonotopic areas are oriented along an oblique posterior-to-anterior axis with mirror-symmetric frequency gradients perpendicular to HG, as in the macaque. In a second experiment, we tested whether these primary frequency-tuned units were modulated by selective attention to preferred vs. non-preferred sound frequencies in the dynamic manner needed to account for human listening abilities in noisy environments, such as cocktail parties or busy streets. We used a dual-stream selective attention experiment where subjects attended to one of two competing tonal streams presented simultaneously to different ears. Attention to low-frequency tones (250 Hz) enhanced neural responses within low-frequency-tuned voxels relative to high (4000 Hz), and vice versa when at-tention switched from high to low. Human PAC is able to tune into attended frequency channels and can switch frequencies on demand, like a radio. In a third experiment, we investigated repetition suppression effects to environmental sounds within primary and non-primary early-stage auditory areas, identified with the tonotopic mapping design. Repeated presentations of sounds from the same sources, as compared to different sources, gave repetition suppression effects within posterior and medial non-primary areas of the right hemisphere, reflecting their potential involvement in semantic representations. These three studies were conducted at 7 Tesla with high-resolution imaging. However, 7 Tesla scanners are, for the moment, not yet used for clinical diagnosis and mostly reside in institutions external to hospitals. Thus, hospital-based clinical functional and structural studies are mainly performed using lower field systems (1.5 or 3 Tesla). In a fourth experiment, we acquired tonotopic maps at 3 and 7 Tesla and evaluated the consistency of a tonotopic mapping paradigm between scanners. Mirror-symmetric gradients within PAC were highly similar at 7 and 3 Tesla across renderings at different spatial resolutions. We concluded that the tonotopic mapping paradigm is robust and suitable for definition of primary tonotopic areas, also at 3 Tesla. Finally, in a fifth study, we considered whether focal brain lesions alter tonotopic representations in the intact ipsi- and contralesional primary auditory cortex in three patients with hemispheric or cerebellar lesions, without and with auditory complaints. We found evidence for tonotopic reorganisation at the level of the primary auditory cortex in cases of brain lesions independently of auditory complaints. Overall, these results reflect a certain degree of plasticity within primary auditory cortex in different populations of subjects, assessed at different field strengths. - La cartographie du cortex auditif chez l'humain est difficile à réaliser avec des techniques d'imagerie fonctionnelle standard, étant donné sa petite taille et position angulaire le long de la fissure sylvienne. En conséquence, le nombre et l'emplacement exacts des différentes aires du cortex auditif restent inconnus chez l'homme. Lors d'une première expérience, nous avons mesuré, avec de l'imagerie par résonance magnétique à haute intensité (IRMf à 7 Tesla) chez des sujets humains sains, deux larges aires au sein du cortex auditif primaire (PAC; Al et R) avec une représentation spécifique des fréquences pures préférées - ou tonotopie. Nos résultats ont démontré une relation anatomico- fonctionnelle qui définit clairement la position du PAC à travers toutes les variantes du gyrus d'Heschl's (HG). Les aires tonotopiques du PAC humain sont orientées le long d'un axe postéro-antérieur oblique avec des gradients de fréquences spécifiques perpendiculaires à HG, d'une manière similaire à celles mesurées chez le singe. Dans une deuxième expérience, nous avons testé si ces aires primaires pouvaient être modulées, de façon dynamique, par une attention sélective pour des fréquences préférées par rapport à celles non-préférées. Cette modulation est primordiale lors d'interactions sociales chez l'humain en présence de bruits distracteurs tels que d'autres discussions ou un environnement sonore nuisible (comme par exemple, dans la circulation routière). Dans cette étude, nous avons utilisé une expérience d'attention sélective où le sujet devait être attentif à une des deux voies sonores présentées simultanément à chaque oreille. Lorsque le sujet portait était attentif aux sons de basses fréquences (250 Hz), la réponse neuronale relative à ces fréquences augmentait par rapport à celle des hautes fréquences (4000 Hz), et vice versa lorsque l'attention passait des hautes aux basses fréquences. De ce fait, nous pouvons dire que PAC est capable de focaliser sur la fréquence attendue et de changer de canal selon la demande, comme une radio. Lors d'une troisième expérience, nous avons étudié les effets de suppression due à la répétition de sons environnementaux dans les aires auditives primaires et non-primaires, d'abord identifiées via le protocole de la première étude. La présentation répétée de sons provenant de la même source sonore, par rapport à de sons de différentes sources sonores, a induit un effet de suppression dans les aires postérieures et médiales auditives non-primaires de l'hémisphère droite, reflétant une implication de ces aires dans la représentation de la catégorie sémantique. Ces trois études ont été réalisées avec de l'imagerie à haute résolution à 7 Tesla. Cependant, les scanners 7 Tesla ne sont pour le moment utilisés que pour de la recherche fondamentale, principalement dans des institutions externes, parfois proches du patient mais pas directement à son chevet. L'imagerie fonctionnelle et structurelle clinique se fait actuellement principalement avec des infrastructures cliniques à 1.5 ou 3 Tesla. Dans le cadre dune quatrième expérience, nous avons avons évalués la cohérence du paradigme de cartographie tonotopique à travers différents scanners (3 et 7 Tesla) chez les mêmes sujets. Nos résultats démontrent des gradients de fréquences définissant PAC très similaires à 3 et 7 Tesla. De ce fait, notre paradigme de définition des aires primaires auditives est robuste et applicable cliniquement. Finalement, nous avons évalués l'impact de lésions focales sur les représentations tonotopiques des aires auditives primaires des hémisphères intactes contralésionales et ipsilésionales chez trois patients avec des lésions hémisphériques ou cérébélleuses avec ou sans plaintes auditives. Nous avons trouvé l'évidence d'une certaine réorganisation des représentations topographiques au niveau de PAC dans le cas de lésions cérébrales indépendamment des plaintes auditives. En conclusion, nos résultats démontrent une certaine plasticité du cortex auditif primaire avec différentes populations de sujets et différents champs magnétiques.

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The increasing volume of data describing humandisease processes and the growing complexity of understanding, managing, and sharing such data presents a huge challenge for clinicians and medical researchers. This paper presents the@neurIST system, which provides an infrastructure for biomedical research while aiding clinical care, by bringing together heterogeneous data and complex processing and computing services. Although @neurIST targets the investigation and treatment of cerebral aneurysms, the system’s architecture is generic enough that it could be adapted to the treatment of other diseases.Innovations in @neurIST include confining the patient data pertaining to aneurysms inside a single environment that offers cliniciansthe tools to analyze and interpret patient data and make use of knowledge-based guidance in planning their treatment. Medicalresearchers gain access to a critical mass of aneurysm related data due to the system’s ability to federate distributed informationsources. A semantically mediated grid infrastructure ensures that both clinicians and researchers are able to seamlessly access andwork on data that is distributed across multiple sites in a secure way in addition to providing computing resources on demand forperforming computationally intensive simulations for treatment planning and research.