914 resultados para multimedia infographics


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The proliferation of multimedia content and the demand for new audio or video services have fostered the development of a new era based on multimedia information, which allowed the evolution of Wireless Multimedia Sensor Networks (WMSNs) and also Flying Ad-Hoc Networks (FANETs). In this way, live multimedia services require real-time video transmissions with a low frame loss rate, tolerable end-to-end delay, and jitter to support video dissemination with Quality of Experience (QoE) support. Hence, a key principle in a QoE-aware approach is the transmission of high priority frames (protect them) with a minimum packet loss ratio, as well as network overhead. Moreover, multimedia content must be transmitted from a given source to the destination via intermediate nodes with high reliability in a large scale scenario. The routing service must cope with dynamic topologies caused by node failure or mobility, as well as wireless channel changes, in order to continue to operate despite dynamic topologies during multimedia transmission. Finally, understanding user satisfaction on watching a video sequence is becoming a key requirement for delivery of multimedia content with QoE support. With this goal in mind, solutions involving multimedia transmissions must take into account the video characteristics to improve video quality delivery. The main research contributions of this thesis are driven by the research question how to provide multimedia distribution with high energy-efficiency, reliability, robustness, scalability, and QoE support over wireless ad hoc networks. The thesis addresses several problem domains with contributions on different layers of the communication stack. At the application layer, we introduce a QoE-aware packet redundancy mechanism to reduce the impact of the unreliable and lossy nature of wireless environment to disseminate live multimedia content. At the network layer, we introduce two routing protocols, namely video-aware Multi-hop and multi-path hierarchical routing protocol for Efficient VIdeo transmission for static WMSN scenarios (MEVI), and cross-layer link quality and geographical-aware beaconless OR protocol for multimedia FANET scenarios (XLinGO). Both protocols enable multimedia dissemination with energy-efficiency, reliability and QoE support. This is achieved by combining multiple cross-layer metrics for routing decision in order to establish reliable routes.

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The Mobile Cloud Networking project develops among others, several virtualized services and applications, in particular: (1) IP Multimedia Subsystem as a Service that gives the possibility to deploy a virtualized and on-demand instance of the IP Multimedia Subsystem platform, (2) Digital Signage Service as a Service that is based on a re-designed Digital Signage Service architecture, adopting the cloud computing principles, and (3) Information Centric Networking/Content Delivery Network as a Service that is used for distributing, caching and migrating content from other services. Possible designs for these virtualized services and applications have been identified and are being implemented. In particular, the architectures of the mentioned services were specified, adopting cloud computing principles, such as infrastructure sharing, elasticity, on-demand and pay-as-you-go. The benefits of Reactive Programming paradigm are presented in the context of Interactive Cloudified Digital Signage services in a Mobile Cloud Platform, as well as the benefit of interworking between different Mobile Cloud Networking Services as Digital Signage Service and Content Delivery Network Service for better performance of Video on Demand content deliver. Finally, the management of Service Level Agreements and the support of rating, charging and billing has also been considered and defined.

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In this work, we will give a detailed tutorial instruction about how to use the Mobile Multi-Media Wireless Sensor Networks (M3WSN) simulation framework. The M3WSN framework has been published as a scientific paper in the 6th International Workshop on OMNeT++ (2013) [1]. M3WSN framework enables the multimedia transmission of real video se- quence. Therefore, a set of multimedia algorithms, protocols, and services can be evaluated by using QoE metrics. Moreover, key video-related information, such as frame types, GoP length and intra-frame dependency can be used for creating new assessment and optimization solutions. To support mobility, M3WSN utilizes different mobility traces to enable the understanding of how the network behaves under mobile situations. This tutorial will cover how to install and configure the M3WSN framework, setting and running the experiments, creating mobility and video traces, and how to evaluate the performance of different protocols. The tutorial will be given in an environment of Ubuntu 12.04 LTS and OMNeT++ 4.2.

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User experience on watching live videos must be satisfactory even under the inuence of different network conditions and topology changes, such as happening in Flying Ad-Hoc Networks (FANETs). Routing services for video dissemination over FANETs must be able to adapt routing decisions at runtime to meet Quality of Experience (QoE) requirements. In this paper, we introduce an adaptive beaconless opportunistic routing protocol for video dissemination over FANETs with QoE support, by taking into account multiple types of context information, such as link quality, residual energy, buffer state, as well as geographic information and node mobility in a 3D space. The proposed protocol takes into account Bayesian networks to define weight vectors and Analytic Hierarchy Process (AHP) to adjust the degree of importance for the context information based on instantaneous values. It also includes a position prediction to monitor the distance between two nodes in order to detect possible route failure.

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During the last decade wireless mobile communications have progressively become part of the people’s daily lives, leading users to expect to be “alwaysbest-connected” to the Internet, regardless of their location or time of day. This is indeed motivated by the fact that wireless access networks are increasingly ubiquitous, through different types of service providers, together with an outburst of thoroughly portable devices, namely laptops, tablets, mobile phones, among others. The “anytime and anywhere” connectivity criterion raises new challenges regarding the devices’ battery lifetime management, as energy becomes the most noteworthy restriction of the end-users’ satisfaction. This wireless access context has also stimulated the development of novel multimedia applications with high network demands, although lacking in energy-aware design. Therefore, the relationship between energy consumption and the quality of the multimedia applications perceived by end-users should be carefully investigated. This dissertation addresses energy-efficient multimedia communications in the IEEE 802.11 standard, which is the most widely used wireless access technology. It advances the literature by proposing a unique empirical assessment methodology and new power-saving algorithms, always bearing in mind the end-users’ feedback and evaluating quality perception. The new EViTEQ framework proposed in this thesis, for measuring video transmission quality and energy consumption simultaneously, in an integrated way, reveals the importance of having an empirical and high-accuracy methodology to assess the trade-off between quality and energy consumption, raised by the new end-users’ requirements. Extensive evaluations conducted with the EViTEQ framework revealed its flexibility and capability to accurately report both video transmission quality and energy consumption, as well as to be employed in rigorous investigations of network interface energy consumption patterns, regardless of the wireless access technology. Following the need to enhance the trade-off between energy consumption and application quality, this thesis proposes the Optimized Power save Algorithm for continuous Media Applications (OPAMA). By using the end-users’ feedback to establish a proper trade-off between energy consumption and application performance, OPAMA aims at enhancing the energy efficiency of end-users’ devices accessing the network through IEEE 802.11. OPAMA performance has been thoroughly analyzed within different scenarios and application types, including a simulation study and a real deployment in an Android testbed. When compared with the most popular standard power-saving mechanisms defined in the IEEE 802.11 standard, the obtained results revealed OPAMA’s capability to enhance energy efficiency, while keeping end-users’ Quality of Experience within the defined bounds. Furthermore, OPAMA was optimized to enable superior energy savings in multiple station environments, resulting in a new proposal called Enhanced Power Saving Mechanism for Multiple station Environments (OPAMA-EPS4ME). The results of this thesis highlight the relevance of having a highly accurate methodology to assess energy consumption and application quality when aiming to optimize the trade-off between energy and quality. Additionally, the obtained results based both on simulation and testbed evaluations, show clear benefits from employing userdriven power-saving techniques, such as OPAMA, instead of IEEE 802.11 standard power-saving approaches.

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The evolution of wireless access technologies and mobile devices, together with the constant demand for video services, has created new Human-Centric Multimedia Networking (HCMN) scenarios. However, HCMN poses several challenges for content creators and network providers to deliver multimedia data with an acceptable quality level based on the user experience. Moreover, human experience and context, as well as network information play an important role in adapting and optimizing video dissemination. In this paper, we discuss trends to provide video dissemination with Quality of Experience (QoE) support by integrating HCMN with cloud computing approaches. We identified five trends coming from such integration, namely Participatory Sensor Networks, Mobile Cloud Computing formation, QoE assessment, QoE management, and video or network adaptation.

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This dissertation focuses on factors of multimedia job aids that modify workload, protocol adherence and clinical errors in community health workers. Literature shows that community health workers performance is not acceptable even with support of paper job aids. There are cognitive theories that try to explain reasons why the performance of community health workers is poor regardless of the access to paper based-job aid. Based on cognitive science and multimedia design theories an intervention was designed to compare alternative representations for the information contained on paper job aids and the capability of this new designed job aids to enhance community health workers performance. The dissertation is divided in 5 main parts: 1. identification and description of the problem, 2. a methodological approach to create and evaluate an intervention, 3. Presentation of results of the intervention evaluation, 4. Discussion of findings and 5. Conclusions

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Esta ponencia analiza la usabilidad, mutación y dominio de una interfaz multimedia determinada con un enfoque tecnológico sociocultural, económico y productivo; partiendo de la utilización, masificación, mercantilización y difusión de contenidos electrónicos que culminan en procesos de domesticación de los mismos para su posterior remediación. La construcción de lenguajes en tanto actividades concretas dentro de interfases de uso común, están presentes en el marco de practicas culturales que sectores de la población mantienen al seno de sus vidas cotidianas. Así, el usuario apropia, consume y reinterpreta lenguajes impuestos mediante la creación de otros nuevos, que destaquen/condicionen la utilización de dispositivos e interfases dadas. Reflexionando entonces, sobre el affordance entre el usuario y la máquina en tanto intercambio comunicativo; esta ponencia toma como ejemplo el registro 'amateur' de la gira Lights In The Sky de la agrupación Nine Inch Nails en 2007 entendiendo que, a partir de la estandarización de formatos de transmisión de datos, particularmente de tecnologías aplicadas a la difusión e intercambio de contenidos musicales, nos ubicamos al frente de un nuevo punto de partida, condicionado y potenciado por un ciclo de experiencias y desarrollo lingüístico que ha corrido de la mano del ciclo tecnológico de la ultima década

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Esta ponencia analiza la usabilidad, mutación y dominio de una interfaz multimedia determinada con un enfoque tecnológico sociocultural, económico y productivo; partiendo de la utilización, masificación, mercantilización y difusión de contenidos electrónicos que culminan en procesos de domesticación de los mismos para su posterior remediación. La construcción de lenguajes en tanto actividades concretas dentro de interfases de uso común, están presentes en el marco de practicas culturales que sectores de la población mantienen al seno de sus vidas cotidianas. Así, el usuario apropia, consume y reinterpreta lenguajes impuestos mediante la creación de otros nuevos, que destaquen/condicionen la utilización de dispositivos e interfases dadas. Reflexionando entonces, sobre el affordance entre el usuario y la máquina en tanto intercambio comunicativo; esta ponencia toma como ejemplo el registro 'amateur' de la gira Lights In The Sky de la agrupación Nine Inch Nails en 2007 entendiendo que, a partir de la estandarización de formatos de transmisión de datos, particularmente de tecnologías aplicadas a la difusión e intercambio de contenidos musicales, nos ubicamos al frente de un nuevo punto de partida, condicionado y potenciado por un ciclo de experiencias y desarrollo lingüístico que ha corrido de la mano del ciclo tecnológico de la ultima década

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Esta ponencia analiza la usabilidad, mutación y dominio de una interfaz multimedia determinada con un enfoque tecnológico sociocultural, económico y productivo; partiendo de la utilización, masificación, mercantilización y difusión de contenidos electrónicos que culminan en procesos de domesticación de los mismos para su posterior remediación. La construcción de lenguajes en tanto actividades concretas dentro de interfases de uso común, están presentes en el marco de practicas culturales que sectores de la población mantienen al seno de sus vidas cotidianas. Así, el usuario apropia, consume y reinterpreta lenguajes impuestos mediante la creación de otros nuevos, que destaquen/condicionen la utilización de dispositivos e interfases dadas. Reflexionando entonces, sobre el affordance entre el usuario y la máquina en tanto intercambio comunicativo; esta ponencia toma como ejemplo el registro 'amateur' de la gira Lights In The Sky de la agrupación Nine Inch Nails en 2007 entendiendo que, a partir de la estandarización de formatos de transmisión de datos, particularmente de tecnologías aplicadas a la difusión e intercambio de contenidos musicales, nos ubicamos al frente de un nuevo punto de partida, condicionado y potenciado por un ciclo de experiencias y desarrollo lingüístico que ha corrido de la mano del ciclo tecnológico de la ultima década

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The emerging use of real-time 3D-based multimedia applications imposes strict quality of service (QoS) requirements on both access and core networks. These requirements and their impact to provide end-to-end 3D videoconferencing services have been studied within the Spanish-funded VISION project, where different scenarios were implemented showing an agile stereoscopic video call that might be offered to the general public in the near future. In view of the requirements, we designed an integrated access and core converged network architecture which provides the requested QoS to end-to-end IP sessions. Novel functional blocks are proposed to control core optical networks, the functionality of the standard ones is redefined, and the signaling improved to better meet the requirements of future multimedia services. An experimental test-bed to assess the feasibility of the solution was also deployed. In such test-bed, set-up and release of end-to-end sessions meeting specific QoS requirements are shown and the impact of QoS degradation in terms of the user perceived quality degradation is quantified. In addition, scalability results show that the proposed signaling architecture is able to cope with large number of requests introducing almost negligible delay.

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Enriching knowledge bases with multimedia information makes it possible to complement textual descriptions with visual and audio information. Such complementary information can help users to understand the meaning of assertions, and in general improve the user experience with the knowledge base. In this paper we address the problem of how to enrich ontology instances with candidate images retrieved from existing Web search engines. DBpedia has evolved into a major hub in the Linked Data cloud, interconnecting millions of entities organized under a consistent ontology. Our approach taps into the Wikipedia corpus to gather context information for DBpedia instances and takes advantage of image tagging information when this is available to calculate semantic relatedness between instances and candidate images. We performed experiments with focus on the particularly challenging problem of highly ambiguous names. Both methods presented in this work outperformed the baseline. Our best method leveraged context words from Wikipedia, tags from Flickr and type information from DBpedia to achieve an average precision of 80%.

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This paper presents an alternative Forward Error Correction scheme, based on Reed-Solomon codes, with the aim of protecting the transmission of RTP-multimedia streams: the inter-packet symbol approach. This scheme is based on an alternative bit structure that allocates each symbol of the Reed-Solomon code in several RTP-media packets. This characteristic permits to exploit better the recovery capability of Reed-Solomon codes against bursty packet losses. The performance of our approach has been studied in terms of encoding/decoding time versus recovery capability, and compared with other proposed schemes in the literature. The theoretical analysis has shown that our approach allows the use of a lower size of the Galois Fields compared to other solutions. This lower size results in a decrease of the required encoding/decoding time while keeping a comparable recovery capability. Finally, experimental results have been carried out to assess the performance of our approach compared to other schemes in a simulated environment, where models for wireless and wireline channels have been considered.