124 research outputs found
The Big Bang of Originality and Effectiveness: A Dynamic Creativity Framework and Its Application to Scientific Missions
This article introduces a theoretical framework to conceptualize the dynamics of the phenomenon of creativity, which is then applied to the specific case of scientific missions for the exploration of the universe. Static definitions of creativity are insufficient for this purpose, as they fail to describe states of creative inconclusiveness as well as the time and culture-dependent estimation of the value of the outcomes of a creative process; therefore, a dynamic definition of creativity is introduced, justified, and adopted to build a dynamic creativity framework. Within this framework, creativity episodes are shown to be mutually interconnected through several mechanisms (past and future concatenation, estimation, and exaptation), to form a dynamic universal creativity process (DUCP), the beginning of which can be traced back to the Big Bang of our universe. The DUCP entails several layers of complexity (material, biological, sociocultural, and artificial), showing that creativity is not only a psychological construct for humans but rather a unifying cosmological principle. Context embeddedness is discussed in-depth, introducing a taxonomy based on the concepts of tightness and looseness as applied to conceptual space and time. This theoretical framework is, then, applied to the discussion of the design, realization, and operations of scientific missions for the exploration of the universe, taking as a reference the terminology adopted by the European Space Agency
Peer-to-Peer Cooperative Positioning Part I: GNSS Aided Acquisition
To improve the performance of GNSS receivers in hostile environments, we consider a Cooperative Positioning approach, where receivers exchange data and information with their neighbors. We focus on unstructured P2P networks, without a control or fusion center. We show that a significant reduction of the acquisition time can indeed by achieved when GNSS aiding quantities like Doppler, satellite Carrierto-Noise ratio and secondary code delay are provided by some aiding peers. The approach is clearly similar to that of Assisted GNSS, but does not require a fixed infrastructure and may better take into account the local environment. Since, in the near future, multi-standard devices will be more and more inter-connected, GNSS Cooperative Positioning may soon become an alternative or a complement to
fixed augmentation system
SatNEx: A Network of Excellence Providing Training in Satellite Communications
YesSatellite communications represents a specialised area of telecommunications. While the development of satellite technology is relatively slow in comparison to wireless networks evolution, due to the need for high reliability, the services that satellites are able to offer are evolving at much the same pace as their terrestrial counterparts. It is within this context that the satellite communications network of excellence (SatNEx) has evolved its initiative, the aim being to serve the engineering community with the latest technological trends, while also providing a solid grounding in the fundamentals for those new to the subject area.European Commission Framework Programme
Clorofilômetro no ajuste da adubação nitrogenada em cobertura para o milho de alta produtividade
Variação espacial da resposta do milho à adubação nitrogenada de cobertura em lavoura no cerrado
ISI - The Integral SatCom Initiative Towards FP7
As the worldwide telecommunications network is evolving fast, and histori-cally separate sectors are converging into a single competition arena, there is an apparent need to coordinate efforts in the field of satellite communications, in order to maximize its chances for business consolidation and growth. This is precisely the purpose of the Integral Satcom Initiative (ISI), a Technology Platform which is being set up in Europe in view of the upcoming 7th Framework Programme (FP7) of the European Union (EU), and of the im-plementation of the European Space Policy, in collaboration with the Euro-pean Space Agency (ESA). This perspective article highlights the ISI found-ing principles and its present status
Study of Satellite Role in 4G Mobile Networks
The basic mission of the present study is to produce a germinal effort towards the design of the strategy to define and create a role for Satellite in 4G networks. The study will have to consider market, business, technical, regulatory, and standardization issues. The results shall be convincing enough to initiate a chain reaction in the enlarged Satcoms community, ambitious enough to stimulate a widespread investment in research, realistic enough to avoid the risk of taking over-optimistic avenues. The efforts will of course have to be balanced with respect to the available time and resources, but the achievements can be maximized through the synergies created in a properly balanced team. There is a need to have competences in both satellite and terrestrial domains, and to cover business, technical, standardization and regulatory aspects. We believe the proposed consortium contains all necessary ingredients to embrace the complexity and fulfil the mission
Closed-Form distribution for soft differential detection in fast rice fading with diversity
A closed-form expression is given for the probability density function of the output of a soft differential demodulator in a fast Rice fading channel with L diversity paths. This expression can be used to evaluate the performance of coded differential BPSK with soft detection for mobile communication applications. As a by-product, the error probability for hard detection in the same channel conditions is also found. Some analytical results are shown and confirmed by simulation
Probability of error and outage in a Rice-lognormal channel for terrestrial and satellite personal communications
This letter addresses performance evaluation in a nonselective fading channel modeled by a combination of Rice and lognormal (RLN) statistics, The RLN model is valid under widely different environmental conditions, both for terrestrial cellular and for satellite personal communication systems, The letter provides semianalytical expressions for the average error probability in the RLN channel for coherent M-ary phase shift keying (PSK) and noncoherent M-ary orthogonal transmissions, then it highlights the relationship between outage probability and cell coverage for macro and microcellular systems, and finally it provides some error probability results for nongeostationary (non-GEO) satellite systems
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