55,901 research outputs found
Numerical Testing of The Rare Earth Hypothesis using Monte Carlo Realisation Techniques
The Search for Extraterrestrial Intelligence (SETI) has thus far failed to
provide a convincing detection of intelligent life. In the wake of this null
signal, many "contact pessimistic" hypotheses have been formulated, the most
famous of which is the Rare Earth Hypothesis. It postulates that although
terrestrial planets may be common, the exact environmental conditions that
Earth enjoys are rare, perhaps unique. As a result, simple microbial life may
be common, but complex metazoans (and hence intelligence) will be rare. This
paper uses Monte Carlo Realisation Techniques to investigate the Rare Earth
Hypothesis, in particular the environmental criteria considered imperative to
the existence of intelligence on Earth.
By comparing with a less restrictive, more optimistic hypothesis, the data
indicates that if the Rare Earth hypothesis is correct, intelligent
civilisation will indeed be relatively rare. Studying the separations of pairs
of civilisations shows that most intelligent civilisation pairs (ICPs) are
unconnected: that is, they will not be able to exchange signals at lightspeed
in the limited time that both are extant. However, the few ICPs that are
connected are strongly connected, being able to participate in numerous
exchanges of signals. This may provide encouragement for SETI researchers:
although the Rare Earth Hypothesis is in general a contact-pessimistic
hypothesis, it may be a "soft" or "exclusive" hypothesis, i.e. it may contain
facets that are latently contact-optimistic.Comment: 13 pages, 10 figures, accepted for publication in the International
Journal of Astrobiolog
The Entropy Principle and the Influence of Sociological Pressures on SETI
We begin with the premise that the law of entropy could prove to be
fundamental for the evolution of intelligent life and the advent of
technological civilization. Building on recent theoretical results, we combine
a modern approach to evolutionary theory with Monte Carlo Realization
Techniques. A numerical test for a proposed significance of the law of entropy
within the evolution of intelligent species is performed and results are
compared with a neutral test hypothesis. Some clarifying aspects on the
emergence of intelligent species arise and are discussed in the framework of
contemporary astrobiology.Comment: 11 pages, 5 figures, accepted for publication in the International
Journal of Astrobiolog
Virulence as a Model for Interplanetary and Interstellar Colonisation - Parasitism or Mutualism
In the light of current scientific assessments of human-induced climate
change, we investigate an experimental model to inform how resource-use
strategies may influence interplanetary and interstellar colonisation by
intelligent civilisations. In doing so, we seek to provide an additional aspect
for refining the famed Fermi Paradox. The model described is necessarily
simplistic, and the intent is to simply obtain some general insights to inform
and inspire additional models. We model the relationship between an intelligent
civilisation and its host planet as symbiotic, where the the relationship
between the symbiont and the host species (the civilisation and the planets
ecology, respectively) determines the fitness and ultimate survival of both
organisms.
We perform a series of Monte Carlo Realisation simulations, where
civilisations pursue a variety of different relationships/strategies with their
host planet, from mutualism to parasitism, and can consequently 'infect' other
planets/hosts. We find that parasitic civilisations are generally less
effective at survival than mutualist civilisations, provided that interstellar
colonisation is inefficient (the maximum velocity of colonisation/infection is
low). However, as the colonisation velocity is increased, the strategy of
parasitism becomes more successful, until they dominate the 'population'. This
is in accordance with predictions based on island biogeography and r/K
selection theory. While heavily assumption dependent, we contend that this
provides a fertile approach for further application of insights from
theoretical ecology for extraterrestrial colonisation - while also potentially
offering insights for understanding the human-Earth relationship and the
potential for extraterrestrial human colonisation.Comment: 18 pages, 7 figures, published in the International Journal of
Astrobiolog
Fine-grained traffic state estimation and visualisation
Tools for visualising the current traffic state are used by local authorities for strategic monitoring of the traffic network and by everyday users for planning their journey. Popular visualisations include those provided by Google Maps and by Inrix. Both employ a traffic lights colour-coding system, where roads on a map are coloured green if traffic is flowing normally and red or black if there is congestion. New sensor technology, especially from wireless sources, is allowing resolution down to lane level. A case study is reported in which a traffic micro-simulation test bed is used to generate high-resolution estimates. An interactive visualisation of the fine-grained traffic state is presented. The visualisation is demonstrated using Google Earth and affords the user a detailed three-dimensional view of the traffic state down to lane level in real time
Unattended network operations technology assessment study. Technical support for defining advanced satellite systems concepts
The results are summarized of an unattended network operations technology assessment study for the Space Exploration Initiative (SEI). The scope of the work included: (1) identified possible enhancements due to the proposed Mars communications network; (2) identified network operations on Mars; (3) performed a technology assessment of possible supporting technologies based on current and future approaches to network operations; and (4) developed a plan for the testing and development of these technologies. The most important results obtained are as follows: (1) addition of a third Mars Relay Satellite (MRS) and MRS cross link capabilities will enhance the network's fault tolerance capabilities through improved connectivity; (2) network functions can be divided into the six basic ISO network functional groups; (3) distributed artificial intelligence technologies will augment more traditional network management technologies to form the technological infrastructure of a virtually unattended network; and (4) a great effort is required to bring the current network technology levels for manned space communications up to the level needed for an automated fault tolerance Mars communications network
Case study based approach to integration of sustainable design analysis, performance and building information modelling
This paper presents a case study based research of both the method and technology for integration of sustainable design analysis (SDA) and building information modelling (BIM) within smart built environments (SBE). Level 3 BIM federation and integration challenges are recognised and improvements suggested, including issues with combining geometry and managing attribute data. The research defines SDA as rapid and quantifiable analysis of diverse sustainable alternatives and ‘what if’ scenarios posed by a design team and client during the early stages of the project, where the benefits of correct decisions can significantly exceed the actual investment required. The SDA concept and BIM integration findings are explained through a convergence from conceptualisation to calculation stages, emphasising the importance of an iterative over a linear approach. The approach allowed for a multitude of “what if” scenarios to be analysed, leading to more informed sustainable solutions at the right stages of the project development, with a generally lower level of detail (LOD) and computational/modelling effort required. In addition, the final stage of Building Regulations Part L compliance calculations was reached with a lot greater level of certainty, in terms of its requirements. Finally, a strategy for long term performance monitoring and evaluation of the building design in terms of its environmental sustainability is presented, via integration between BIM and SBE (Smart Built Environment) technologies
Intelligent OFDM telecommunication system. Part 3. Anti-eavesdropping and anti-jamming properties of system, based on many-parameter wavelet and Golay transforms
In this paper, we aim to investigate the superiority and practicability of many-parameter Fourier transforms (MPFT) from the physical layer security (PHY-LS) perspective. We propose novel Intelligent OFDM-telecommunication system (Intelligent-OFDM-TCS), based on MPFT. New system uses inverse MPFT for modulation at the transmitter and direct MPFT for demodulation at the receiver. The purpose of employing the MPFTs is to improve the PHY-LS of wireless transmissions against to the wide-band anti-jamming communication. Each MPFT depends on finite set of independent parameters (angles), which could be changed independently one from another. When parameters are changed, multi-parametric transform is also changed taking form of a set known (and unknown) orthogonal (or unitary) transforms. We implement the following performances as bit error rate (BER), symbol error rate (SER), the Shannon-Wyner secrecy capacity (SWSC) for novel Intelligent-MPWT-OFDM-TCS. Previous research has shown that the conventional OFDM TCS based on discrete Fourier transform (DFT) has unsatisfactory characteristics in BER, SWSC and in anti-eavesdropping communications. We study Intelligent-MPWT-OFDM-TCS to find out optimal values of angle parameters of MPFT optimized BER, SWSC, anti-eavesdropping effects. Simulation results show that the proposed Intelligent OFDM-TCS have better performances than the conventional OFDM system based on DFT against eavesdropping. © 2019 IOP Publishing Ltd. All rights reserved
Genetic algorithms for satellite scheduling problems
Recently there has been a growing interest in mission operations scheduling problem. The problem, in a variety of formulations, arises in management of satellite/space missions requiring efficient allocation of user requests to make possible the communication between operations teams and spacecraft systems. Not only large space agencies, such as ESA (European Space Agency) and NASA, but also smaller research institutions and universities can establish nowadays their satellite mission, and thus need intelligent systems to automate the allocation of ground station services to space missions. In this paper, we present some relevant formulations of the satellite scheduling viewed as a family of problems and identify various forms of optimization objectives. The main complexities, due highly constrained nature, windows accessibility and visibility, multi-objectives and conflicting objectives are examined. Then, we discuss the resolution of the problem through different heuristic methods. In particular, we focus on the version of ground station scheduling, for which we present computational results obtained with Genetic Algorithms using the STK simulation toolkit.Peer ReviewedPostprint (published version
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