639 resultados para redundancy


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Nowadays several electronics devices support digital videos. Some examples of these devices are cellphones, digital cameras, video cameras and digital televisions. However, raw videos present a huge amount of data, millions of bits, for their representation as the way they were captured. To store them in its primary form it would be necessary a huge amount of disk space and a huge bandwidth to allow the transmission of these data. The video compression becomes essential to make possible information storage and transmission. Motion Estimation is a technique used in the video coder that explores the temporal redundancy present in video sequences to reduce the amount of data necessary to represent the information. This work presents a hardware architecture of a motion estimation module for high resolution videos according to H.264/AVC standard. The H.264/AVC is the most advanced video coder standard, with several new features which allow it to achieve high compression rates. The architecture presented in this work was developed to provide a high data reuse. The data reuse schema adopted reduces the bandwidth required to execute motion estimation. The motion estimation is the task responsible for the largest share of the gains obtained with the H.264/AVC standard so this module is essential for final video coder performance. This work is included in Rede H.264 project which aims to develop Brazilian technology for Brazilian System of Digital Television

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This paper is set in a scenario in which higher education institutions suffer from external pressure to increase efficiency. The legislation after the Law of Directives and Bases for Education (LDBE), from 1996, is characterized by the fragmentation in its implementation, raising a concern with flexibility and innovation in several normative devices as well as aspects that must be incorporated to its organizational structure. The policies examined in this thesis are: Distance Education (DE); Law of Innovation and the Program of Support to Restructuring and Expansion of Federal Universities (PSREFU). This thesis aims to observe to what extent the characteristics of innovation and flexibility, which mark the new post- LDBE educational legislation, influence the organizational redesign of the Federal University of Ceará (UFC). For being about implementation policies, using contingency approach in order to collect the internal dynamics permeating the redesign of higher education institutions, the thesis focuses on the impacts caused by flexibility and innovation. This is a qualitative research, with case study methods, archive research and semi-structured interviews with members of the university administration. The results don t allow us to confirm the adoption of a more flexible and innovative configuration in the university but it is possible to identify the presence of those elements in the implementation changes, characterizing the hybrid structure. The changes mainly expose the extension of the management of projects to the administrative and academic components related to the institution. In terms of projection, the study found changes in the elements which characterize the current setting and the tendency of the university for adopting a diverse organizational structure. However, if the decentralization of management persists, the academic units may adopt their own structural solutions, but with no evidence of changes in the professional organization in most units. In this perspective, this thesis states that there are difficulties when incorporating innovation and flexibility to their organizational structure, which lead to improvised solutions, superposing skills through the redundancy of structures created with the same purpose or copying exogenous solutions

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Biodiversity is organised into complex ecological networks of interacting species in local ecosystems, but our knowledge about the effects of habitat fragmentation on such systems remains limited. We consider the effects of this key driver of both local and global change on both mutualistic and antagonistic systems at different levels of biological organisation and spatiotemporal scales.There is a complex interplay of patterns and processes related to the variation and influence of spatial, temporal and biotic drivers in ecological networks. Species traits (e.g. body size, dispersal ability) play an important role in determining how networks respond to fragment size and isolation, edge shape and permeability, and the quality of the surrounding landscape matrix. Furthermore, the perception of spatial scale (e.g. environmental grain) and temporal effects (time lags, extinction debts) can differ markedly among species, network modules and trophic levels, highlighting the need to develop a more integrated perspective that considers not just nodes, but the structural role and strength of species interactions (e.g. as hubs, spatial couplers and determinants of connectance, nestedness and modularity) in response to habitat fragmentation.Many challenges remain for improving our understanding: the likely importance of specialisation, functional redundancy and trait matching has been largely overlooked. The potentially critical effects of apex consumers, abundant species and supergeneralists on network changes and evolutionary dynamics also need to be addressed in future research. Ultimately, spatial and ecological networks need to be combined to explore the effects of dispersal, colonisation, extinction and habitat fragmentation on network structure and coevolutionary dynamics. Finally, we need to embed network approaches more explicitly within applied ecology in general, because they offer great potential for improving on the current species-based or habitat-centric approaches to our management and conservation of biodiversity in the face of environmental change.

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This article has the purpose to review the main codes used to detect and correct errors in data communication specifically in the computer's network. The Hamming's code and the Ciclic Redundancy Code (CRC) are presented as the focus of this article as well as CRC hardware implementation. Each code is reviewed in details in order to fill the gaps in the literature and to make it accessible to the computer science and engineering students as well as to anyone who may be interested in learning the technique to treat error in data communication.

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Because anuran species are highly dependent on environmental variables, we hypothesized that anuran species richness and the number of reproductive modes from different Brazilian localities vary according to climatic and altitudinal variables. Published data were compiled from 36 Brazilian localities and climatic and altitudinal data were extracted from an available database. A partial redundancy analysis (pRDA) showed that 23.5% of the data set's variation was explained by climatic and altitudinal data, while the remaining 76.5% remained unexplained. This analysis suggests that other factors not analysed herein may also be important for predicting anuran species richness and the number of reproductive modes in Brazil. Altitude and total annual rainfall were positively correlated with anuran species richness and the number of reproductive modes, and total annual rainfall was strongly associated with these two biotic variables in the triplot of pRDA. The positive association of total annual rainfall and the negative association of the concentration of annual rainfall were already expected based on physiological and reproductive requirements of anurans. On the other hand, temperature was not associated with richness or the number of reproductive modes. Copyright © 2010 Cambridge University Press.

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The maintenance of a given body orientation is obtained by the complex relation between sensory information and muscle activity. Therefore, this study purpose was to review the role of visual, somatosensory, vestibular and auditory information in the maintenance and control of the posture. Method. a search by papers for the last 24 years was done in the PubMed and CAPES databases. The following keywords were used: postural control, sensory information, vestibular system, visual system, somatosensory system, auditory system and haptic system. Results. the influence of each sensory system and its integration were analyzed for the maintenance and control of the posture. Conclusion. the literature showed that there is information redundancy provided by sensory channels. Thus, the central nervous system chooses the main source for the posture control.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Ciências Cartográficas - FCT

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Pós-graduação em Física - IGCE

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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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 realtime 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.