891 resultados para information source
Resumo:
The growing popularity of social networks, and their impact on the daily lives of consumers, contributed to news organizations marking their presence on different online platforms. In the case of Facebook, a social network that began as a personal space, it has gradually transformed into a content-sharing space (Oeldorf-Hirsch & Sundar, 2015). Nowadays, Facebook is the second most viewed website in Portugal (Alexa, 2016), and therefore, it has become crucial for Portuguese news agencies to be present on this social network. Although television continues to be the main information source in Portugal, social networks, and specifically Facebook, are increasingly important in news consumption by users (ERC, 2015). This new way of news dissemination, as well as the proliferation that these contents reach in social networks, led to news agencies exploiting these new channels, both to attract new audiences, and to redirect users to their own websites (Castillo, El-Haddad, Pfeffer, & Stempeck, 2014). Thus, it is important to understand how, and what kind of content these agencies put on their Facebook channels, as well as the strategies they use to share these same contents. This study aims to understand how the main news channels of Portuguese TV (RTP3, SIC Notícias, and TVI24) manage and use the social network Facebook to share news contents. To this end, the authors collected quantitative data of all posts placed on Facebook between February 8 and February 14 2016. Approximately 1063 posts were collected and analysed from the three Facebook pages. The results indicate that two of the three channels extensively used their Facebook pages to share and target content to their official websites. Regarding the news sources and type of media used, the three Portuguese TV news channels use similar strategies. However, in what concerns the main themes and quantity of messages per day, as well as the level of redundancy of information, the three channels manage their pages differently.
Resumo:
The growing popularity of social networks, and their impact on the daily lives of consumers, contributed to news organizations marking their presence on different online platforms. In the case of Facebook, a social network that began as a personal space, it has gradually transformed into a content-sharing space (Oeldorf-Hirsch & Sundar, 2015). Nowadays, Facebook is the second most viewed website in Portugal (Alexa, 2016), and therefore, it has become crucial for Portuguese news agencies to be present on this social network. Although television continues to be the main information source in Portugal, social networks, and specifically Facebook, are increasingly important in news consumption by users (ERC, 2015). This new way of news dissemination, as well as the proliferation that these contents reach in social networks, led to news agencies exploiting these new channels, both to attract new audiences, and to redirect users to their own websites (Castillo, El-Haddad, Pfeffer, & Stempeck, 2014). Thus, it is important to understand how, and what kind of content these agencies put on their Facebook channels, as well as the strategies they use to share these same contents. This study aims to understand how the main news channels of Portuguese TV (RTP3, SIC Notícias, and TVI24) manage and use the social network Facebook to share news contents. To this end, the authors collected quantitative data of all posts placed on Facebook between February 8 and February 14 2016. Approximately 1063 posts were collected and analysed from the three Facebook pages. The results indicate that two of the three channels extensively used their Facebook pages to share and target content to their official websites. Regarding the news sources and type of media used, the three Portuguese TV news channels use similar strategies. However, in what concerns the main thematic and quantity of messages per day, as well as the level of redundancy of information, the three channels operate their pages differently.
Resumo:
On August 16, 2012 the SIGIR 2012 Workshop on Open Source Information Retrieval was held as part of the SIGIR 2012 conference in Portland, Oregon, USA. There were 2 invited talks, one from industry and one from academia. There were 6 full papers and 6 short papers presented as well as demonstrations of 4 open source tools. Finally there was a lively discussion on future directions for the open source Information Retrieval community. This contribution discusses the events of the workshop and outlines future directions for the community.
Resumo:
Relevation! is a system for performing relevance judgements for information retrieval evaluation. Relevation! is web-based, fully configurable and expandable; it allows researchers to effectively collect assessments and additional qualitative data. The system is easily deployed allowing assessors to smoothly perform their relevance judging tasks, even remotely. Relevation! is available as an open source project at: http://ielab.github.io/relevation.
Resumo:
We consider the problem of transmission of several discrete sources over a multiple access channel (MAC) with side information at the sources and the decoder. Source-channel separation does not hold for this channel. Sufficient conditions are provided for transmission of sources with a given distortion. The channel could have continuous alphabets (Gaussian MAC is a special case). Various previous results are obtained as special cases.
Resumo:
In a three player quantum `Dilemma' game each player takes independent decisions to maximize his/her individual gain. The optimal strategy in the quantum version of this game has a higher payoff compared to its classical counterpart. However, this advantage is lost if the initial qubits provided to the players are from a noisy source. We have experimentally implemented the three player quantum version of the `Dilemma' game as described by Johnson, [N.F. Johnson, Phys. Rev. A 63 (2001) 020302(R)] using nuclear magnetic resonance quantum information processor and have experimentally verified that the payoff of the quantum game for various levels of corruption matches the theoretical payoff. (c) 2007 Elsevier Inc. All rights reserved.
Resumo:
We study the problem of guessing the realization of a finite alphabet source, when some side information is provided, in a setting where the only knowledge the guesser has about the source and the correlated side information is that the joint source is one among a family. We define a notion of redundancy, identify a quantity that measures this redundancy, and study its properties. We then identify good guessing strategies that minimize the supremum redundancy (over the family). The minimum value measures the richness of the uncertainty class.
Resumo:
In this paper we address the problem of transmission of correlated sources over a fast fading multiple access channel (MAC) with partial channel state information available at both the encoders and the decoder. We provide sufficient conditions for transmission with given distortions. Next these conditions are specialized to a Gaussian MAC (GMAC). We provide the optimal power allocation strategy and compare the strategy with various levels of channel state information.
Resumo:
In a typical sensor network scenario a goal is to monitor a spatio-temporal process through a number of inexpensive sensing nodes, the key parameter being the fidelity at which the process has to be estimated at distant locations. We study such a scenario in which multiple encoders transmit their correlated data at finite rates to a distant and common decoder. In particular, we derive inner and outer bounds on the rate region for the random field to be estimated with a given mean distortion.
Resumo:
The functional source coding problem in which the receiver side information (Has-set) and demands (Want-set) include functions of source messages is studied using row-Latin rectangle. The source transmits encoded messages, called the functional source code, in order to satisfy the receiver's demands. We obtain a minimum length using the row-Latin rectangle. Next, we consider the case of transmission errors and provide a necessary and sufficient condition that a functional source code must satisfy so that the receiver can correctly decode the values of the functions in its Want-set.
Resumo:
The paper traces the history of the different documentation media used for information dissemination. Such early media are clay tablets, papyrus, and vellum or parchment codex. The invention of printing however revolutionized the information industry, enabling the production of books in multiple copies. Photography came into documentation mainly to preserve rare materials and those that easily deteriorate. This paper reports the efforts of National Institute for Freshwater Fisheries Research (NIFFR) and Kainji Lake Fisheries Promotion Project (KLFPPP), Nigeria, to develop an Object Oriented Database (OOD) using photographs. The photographs are stored in digitized form on commercial computers, using the program ACDSee 32 for classification, description and retrieval. Specifically the paper focuses on photographs in fisheries as visual communication and expression. Presently, the database contains photo documents about the following aspects of Kainji Lake fisheries: fishing gears and crafts, fish preservation methods