990 resultados para Direct broadcast satellite television


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Esta tese aborda o declínio da audiência das grandes redes de TV aberta e os recursos narrativos que os produtores de programas adotaram para enfrentar essa tendência mundial. O estudo traz um panorama da situação da audiência no âmbito internacional e foca, particularmente, o caso do Brasil, onde três grandes emissoras mantém, no conjunto, uma das mais altas concentrações de público do mundo. Depois de analisar a fragmentação das audiências televisivas nas duas últimas décadas e os números que indicam a crescente dispersão dos telespectadores entre múltiplas ofertas de mídia disponíveis nos dias atuais, o trabalho discute as estratégias de programação e de construção de conteúdos. Além de teóricos que pesquisaram a chamada semiótica televisiva , servem de base para a investigação depoimentos de produtores e análises de programas de grande audiência. O objetivo é revelar os procedimentos utilizados para atrair e manter a atenção dos telespectadores, os quais começam com as medições de audiência e os estudos sobre o comportamento dos consumidores em relação à TV. A tese discute também como ocorre a exposição dos telespectadores em um ambiente onde existem várias opções de dispositivos para ver atrações televisivas ou para fazer outras atividades comunicacionais. A escolha deste tema de investigação partiu do princípio de que a exposiçao é condição essencial para sustentar o estudo de outras fases e outros aspectos do processo de comunicação, como a influência dos meios sobre a cultura e a sociedade. Em um contexto onde a mídia ocupa tanto tempo de nosso cotidiano, o impacto dos meios de comunicação de massa pode ser diretamente proporcional ao número de pessoas que eles alcançam e aos nossos hábitos de consumo de informação e entretenimento.

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In this article we review the methods used by television news channels in their reporting of the clashes between the Hungarian police and refugees at the Serbian-Hungarian border on 16th of September 2015. With the help of content analysis we examine the techniques used by each editorial board to portray events differently,resulting in dissimilar effects on recipients. During the analysis we examine news coverage for one specific day as presented by Hungarian, German and pan-European broadcasters. German news programs were chosen for comparison with Hungarian ones due to the fact that most of the refugees were heading towards Germany. We conclude that there are significant differences between the information that was broadcast according to television channels; owner expectations presumably play an important role in this.

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Recently, wireless network technology has grown at such a pace that scientific research has become a practical reality in a very short time span. Mobile wireless communications have witnessed the adoption of several generations, each of them complementing and improving the former. One mobile system that features high data rates and open network architecture is 4G. Currently, the research community and industry, in the field of wireless networks, are working on possible choices for solutions in the 4G system. 4G is a collection of technologies and standards that will allow a range of ubiquitous computing and wireless communication architectures. The researcher considers one of the most important characteristics of future 4G mobile systems the ability to guarantee reliable communications from 100 Mbps, in high mobility links, to as high as 1 Gbps for low mobility users, in addition to high efficiency in the spectrum usage. On mobile wireless communications networks, one important factor is the coverage of large geographical areas. In 4G systems, a hybrid satellite/terrestrial network is crucial to providing users with coverage wherever needed. Subscribers thus require a reliable satellite link to access their services when they are in remote locations, where a terrestrial infrastructure is unavailable. Thus, they must rely upon satellite coverage. Good modulation and access technique are also required in order to transmit high data rates over satellite links to mobile users. This technique must adapt to the characteristics of the satellite channel and also be efficient in the use of allocated bandwidth. Satellite links are fading channels, when used by mobile users. Some measures designed to approach these fading environments make use of: (1) spatial diversity (two receive antenna configuration); (2) time diversity (channel interleaver/spreading techniques); and (3) upper layer FEC. The author proposes the use of OFDM (Orthogonal Frequency Multiple Access) for the satellite link by increasing the time diversity. This technique will allow for an increase of the data rate, as primarily required by multimedia applications, and will also optimally use the available bandwidth. In addition, this dissertation approaches the use of Cooperative Satellite Communications for hybrid satellite/terrestrial networks. By using this technique, the satellite coverage can be extended to areas where there is no direct link to the satellite. For this purpose, a good channel model is necessary.

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Recently, wireless network technology has grown at such a pace that scientific research has become a practical reality in a very short time span. One mobile system that features high data rates and open network architecture is 4G. Currently, the research community and industry, in the field of wireless networks, are working on possible choices for solutions in the 4G system. The researcher considers one of the most important characteristics of future 4G mobile systems the ability to guarantee reliable communications at high data rates, in addition to high efficiency in the spectrum usage. On mobile wireless communication networks, one important factor is the coverage of large geographical areas. In 4G systems, a hybrid satellite/terrestrial network is crucial to providing users with coverage wherever needed. Subscribers thus require a reliable satellite link to access their services when they are in remote locations where a terrestrial infrastructure is unavailable. The results show that good modulation and access technique are also required in order to transmit high data rates over satellite links to mobile users. The dissertation proposes the use of OFDM (Orthogonal Frequency Multiple Access) for the satellite link by increasing the time diversity. This technique will allow for an increase of the data rate, as primarily required by multimedia applications, and will also optimally use the available bandwidth. In addition, this dissertation approaches the use of Cooperative Satellite Communications for hybrid satellite/terrestrial networks. By using this technique, the satellite coverage can be extended to areas where there is no direct link to the satellite. The issue of Cooperative Satellite Communications is solved through a new algorithm that forwards the received data from the fixed node to the mobile node. This algorithm is very efficient because it does not allow unnecessary transmissions and is based on signal to noise ratio (SNR) measures.

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A sociedade digital nos abraça em todos os aspectos do cotidiano e uma parte significativa da população vive conectada em multiplataformas. Com a instantaneidade dos fluxos de comunicação, vivemos uma rotina onde muitos acessos estão a um “clique” ou toque. A televisão como mídia preponderante durante várias décadas, na sua transição digital comporta uma função além da TV que conhecíamos, como display interativo que se conecta e absorve conteúdos provenientes de várias fontes. Os consagrados modelos mundiais de distribuição de audiovisual, especialmente pelo Broadcast, sofrem as consequências da mudança do comportamento do seu público pelas novas oportunidades de acesso aos conteúdos, agora interativos e sob demanda. Neste contexto, os modelos das SmartTVs (TVs conectadas) em Broadband (Banda Larga) apresentam opções diferenciadas e requerem um espaço cada vez maior na conexão com todos os outros displays. Com este cenário, o presente estudo busca descrever e analisar as novas ofertas de conteúdos, aplicativos, possibilidades e tendências do hibridismo das fontes para a futura TV.

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[No abstract as this is a book chapter: the following represents the first 2 paragraphs.] The screen fills with close-ups of smiling African faces against a black-and-orange background: the carefree child, the gap-toothed man with smoke curling from his pipe. The faces retreat into an outline of a map of Africa as the saccharine background music dissolves into birdsong. The silhouette of an acacia tree appears. This is not the much-derided Western romantic stereotype of the continent: it is an extract from a promotional trailer on CCTV Africa, the embodiment of China’s “soft power” drive and a spearhead of Chinese state television’s overseas expansion. Yet this image is at variance with the English-language channel’s professed ambitions. The Chinese premier, Li Keqiang, himself declared that “CCTV embraces the vision of seeing Africa from an African perspective and reporting Africa from the viewpoint of Africa”. These contradictory messages prompt fundamental questions about CCTV’s expansion into Africa. Are the channel’s English-language news bulletins aimed at African or Chinese viewers? What kind of Africa – and indeed China – do they represent, and could the framing of African events by CCTV News provide an alternative to the perspective of international rivals? Is CCTV’s main mission in Africa to provide news or to act as mouthpiece of the Chinese Communist Party and state? This chapter addresses these questions by applying a cross-cultural variant of framing theory to the news content of CCTV’s Africa Live and that of its closest direct competitor, Focus on Africa from BBC World News TV.

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Estructura formal, textual y oral del discurso públicoExisten tres competencias comunicativas muy valoradas en la sociedad de la información. Primero, la búsqueda, selección y gestión de grandes cantidades de información. Segundo, la redacción de textos claros, concisos y rigurosos. Y en tercer lugar, la exposición y defensa oral de esta información en un discurso público. Tradicionalmente, los estudios de periodismo han abordado estas competencias de forma independiente. Pero actualmente, instituciones y empresas de ámbitos diferentes demandan un perfil profesional capaz de aplicarlas ante cualquier tipo de información y con objetivos diversos. Se propone un modelo integral en tres niveles estructurales basado en teorías, conceptos y estudios específicos de periodismo, oratoria, retórica… o comunicación, en los últimos años. Este modelo puede contribuir a encauzar las investigaciones de académicos y representa una herramienta de entrenamiento para profesionales.

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To evaluate the performance of ocean-colour retrievals of total chlorophyll-a concentration requires direct comparison with concomitant and co-located in situ data. For global comparisons, these in situ match-ups should be ideally representative of the distribution of total chlorophyll-a concentration in the global ocean. The oligotrophic gyres constitute the majority of oceanic water, yet are under-sampled due to their inaccessibility and under-represented in global in situ databases. The Atlantic Meridional Transect (AMT) is one of only a few programmes that consistently sample oligotrophic waters. In this paper, we used a spectrophotometer on two AMT cruises (AMT19 and AMT22) to continuously measure absorption by particles in the water of the ship's flow-through system. From these optical data continuous total chlorophyll-a concentrations were estimated with high precision and accuracy along each cruise and used to evaluate the performance of ocean-colour algorithms. We conducted the evaluation using level 3 binned ocean-colour products, and used the high spatial and temporal resolution of the underway system to maximise the number of match-ups on each cruise. Statistical comparisons show a significant improvement in the performance of satellite chlorophyll algorithms over previous studies, with root mean square errors on average less than half (~ 0.16 in log10 space) that reported previously using global datasets (~ 0.34 in log10 space). This improved performance is likely due to the use of continuous absorption-based chlorophyll estimates, that are highly accurate, sample spatial scales more comparable with satellite pixels, and minimise human errors. Previous comparisons might have reported higher errors due to regional biases in datasets and methodological inconsistencies between investigators. Furthermore, our comparison showed an underestimate in satellite chlorophyll at low concentrations in 2012 (AMT22), likely due to a small bias in satellite remote-sensing reflectance data. Our results highlight the benefits of using underway spectrophotometric systems for evaluating satellite ocean-colour data and underline the importance of maintaining in situ observatories that sample the oligotrophic gyres.

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To evaluate the performance of ocean-colour retrievals of total chlorophyll-a concentration requires direct comparison with concomitant and co-located in situ data. For global comparisons, these in situ match-ups should be ideally representative of the distribution of total chlorophyll-a concentration in the global ocean. The oligotrophic gyres constitute the majority of oceanic water, yet are under-sampled due to their inaccessibility and under-represented in global in situ databases. The Atlantic Meridional Transect (AMT) is one of only a few programmes that consistently sample oligotrophic waters. In this paper, we used a spectrophotometer on two AMT cruises (AMT19 and AMT22) to continuously measure absorption by particles in the water of the ship's flow-through system. From these optical data continuous total chlorophyll-a concentrations were estimated with high precision and accuracy along each cruise and used to evaluate the performance of ocean-colour algorithms. We conducted the evaluation using level 3 binned ocean-colour products, and used the high spatial and temporal resolution of the underway system to maximise the number of match-ups on each cruise. Statistical comparisons show a significant improvement in the performance of satellite chlorophyll algorithms over previous studies, with root mean square errors on average less than half (~ 0.16 in log10 space) that reported previously using global datasets (~ 0.34 in log10 space). This improved performance is likely due to the use of continuous absorption-based chlorophyll estimates, that are highly accurate, sample spatial scales more comparable with satellite pixels, and minimise human errors. Previous comparisons might have reported higher errors due to regional biases in datasets and methodological inconsistencies between investigators. Furthermore, our comparison showed an underestimate in satellite chlorophyll at low concentrations in 2012 (AMT22), likely due to a small bias in satellite remote-sensing reflectance data. Our results highlight the benefits of using underway spectrophotometric systems for evaluating satellite ocean-colour data and underline the importance of maintaining in situ observatories that sample the oligotrophic gyres.

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We measure quality of service (QoS) in a wireless network architecture of transoceanic aircraft. A distinguishing characteristic of the network scheme we analyze is that it mixes the concept of Delay Tolerant Networking (DTN) through the exploitation of opportunistic contacts, together with direct satellite access in a limited number of the nodes. We provide a graph sparsification technique for deriving a network model that satisfies the key properties of a real aeronautical opportunistic network while enabling scalable simulation. This reduced model allows us to analyze the impact regarding QoS of introducing Internet-like traffic in the form of outgoing data from passengers. Promoting QoS in DTNs is usually really challenging due to their long delays and scarce resources. The availability of satellite communication links offers a chance to provide an improved degree of service regarding a pure opportunistic approach, and therefore it needs to be properly measured and quantified. Our analysis focuses on several QoS indicators such as delivery time, delivery ratio, and bandwidth allocation fairness. Obtained results show significant improvements in all metric indicators regarding QoS, not usually achievable on the field of DTNs.

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Since the satellite network plays an irreplaceable role in many fields, how to interconnect it with the ground network has received an unprecedented attention. However, with much more requirements imposed to the current terrestrial network, many serious problems caused by the IP dual-role exposed. In this context, their direct interconnection seems not the most appropriate way. Thus, in this paper, SAT-GRD, an incrementally deployable ID/Loc split network architecture is proposed, aiming to integrate the satellite and ground networks efficiently. Specifically, SAT-GRD separates the identity of both the host and network from the location. Then, it isolates the host from the network, and further divides the whole network into core and edge networks. These make SAT-GRD much more flexible and scalable to achieve heterogeneous network convergence and avoid problems resulting from the overloaded semantics of IP addresses. In addition, much work has been done to implement the proof-of-concept prototype of SAT-GRD, and experimental results prove its feasibility.