1,339 research outputs found

    Ephemeral Londoners: Modelling Lower Class Migration to Eighteenth Century London

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    Between 1750 and 1801 the population of London grew from approximately 750,000 to 1.1 million people. Relocating to London in the eighteenth century only occasionally generated a paper trail, but a significant number of failed migrants were rounded up for ‘wandering and begging’ on the streets and sent back from whence they came to their parish of legal settlement. Records of these removals have been digitised and are used in this paper to model migration into London, to throw light onto the patterns of movement at this time

    The expressive stance: intentionality, expression, and machine art

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    This paper proposes a new interpretive stance for interpreting artistic works and performances that is relevant to artificial intelligence research but also has broader implications. Termed the expressive stance, this stance makes intelligible a critical distinction between present-day machine art and human art, but allows for the possibility that future machine art could find a place alongside our own. The expressive stance is elaborated as a response to Daniel Dennett's notion of the intentional stance, which is critically examined with respect to his specialized concept of rationality. The paper also shows that temporal scale implicitly serves to select between different modes of explanation in prominent theories of intentionality. It also considers the implications of the phenomenological background for systems that produce art

    Post-Turing Methodology: Breaking the Wall on the Way to Artificial General Intelligence

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    This article offers comprehensive criticism of the Turing test and develops quality criteria for new artificial general intelligence (AGI) assessment tests. It is shown that the prerequisites A. Turing drew upon when reducing personality and human consciousness to “suitable branches of thought” re-flected the engineering level of his time. In fact, the Turing “imitation game” employed only symbolic communication and ignored the physical world. This paper suggests that by restricting thinking ability to symbolic systems alone Turing unknowingly constructed “the wall” that excludes any possi-bility of transition from a complex observable phenomenon to an abstract image or concept. It is, therefore, sensible to factor in new requirements for AI (artificial intelligence) maturity assessment when approaching the Tu-ring test. Such AI must support all forms of communication with a human being, and it should be able to comprehend abstract images and specify con-cepts as well as participate in social practices

    Collaboration between Science and Religious Education teachers in Scottish Secondary schools

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    The article reports on quantitative research that examines: (1) the current practice in collaboration; and (2) potential for collaboration between Science and Religious Education teachers in a large sample of Scottish secondary schools. The authors adopt and adapt three models (conflict; concordat and consonance) to interrogate the relationship between science and religion (and the perceived relation between these two subjects in schools) (Astley and Francis 2010). The findings indicate that there is evidence of limited collaboration and, in a few cases, a dismissive attitude towards collaboration (conflict and concordat and very weak consonance). There is, however, evidence of a genuine aspiration for greater collaboration among many teachers (moving towards a more robust consonance model). The article concludes by discussing a number of key factors that must be realised for this greater collaboration to be enacted

    The IDV source J1128+5925, a new candidate for annual modulation?

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    Short time-scale radio variations of compact extragalactic radio sources, known as IntraDay Variability, can be explained in at least some sources by a source-extrinsic effect, in which the variations are interpreted as scintillation of radio waves caused by the turbulent ISM of the Milky Way. One of the most convincing observational arguments in favour of propagation-induced variability is the so called annual modulation of the characteristic variability time-scale, which is due to the orbital motion of the Earth. Data for the recently discovered and highly variable IDV source J1128+5925 are presented. We study the frequency and time dependence of the IDV in this compact quasar. We measure the characteristic variability time-scale of the IDV throughout the year, and analyze whether the observed changes in the variability time-scale are consistent with annual modulation. We monitored the flux density variability of J1128+5925 with dense time sampling between 2.7 and 10.45GHz with the 100m Effelsberg radio telescope of the MPIfR and with the 25m Urumqi radio telescope. From ten observing sessions, we determine the variability characteristics and time-scales. The observed pronounced changes of the variability time-scale of J1128+5925 are modelled with an anisotropic annual modulation model. The observed frequency dependence of the variation is in good agreement with the prediction from interstellar scintillation. Adopting a simple model for the annual modulation model and using also the frequency dependence of the IDV, we derive a lower limit to the distance of the scattering screen and an upper limit to the scintillating source size. The latter is found to be consistent with the measured core size from VLBI.Comment: 15 pages, 9 figures Accepted for publication in Astronomy and Astrophysic

    First Results from MASIV: The Micro-Arcsecond Scintillation-Induced Variability Survey

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    We are undertaking a large-scale, Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey of the northern sky, Dec > 0 deg, at 4.9 GHz with the VLA. Our objective is to construct a sample of 100 to 150 scintillating extragalactic sources with which to examine both the microarcsecond structure and the parent populations of these sources, and to probe the turbulent interstellar medium responsible for the scintillation. We report on our first epoch of observations which revealed variability on timescales ranging from hours to days in 85 of 710 compact flat-spectrum sources. The number of highly variable sources, those with RMS flux density variations greater than 4% of the mean, increases with decreasing source flux density but rapid, large amplitude variables such as J1819+3845 are very rare. When compared with a model for the scintillation due to irregularities in a 500 pc thick electron layer, our preliminary results indicate maximum brightness temperatures ~10E+12 K, similar to those obtained from VLBI surveys even though interstellar scintillation is not subject to the same angular resolution limit.Comment: 18 pages, 5 figures. To appear in the Astronomical Journa

    Interstellar Scintillation of the Polarized Flux Density in Quasar, PKS 0405-385

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    The remarkable rapid variations in radio flux density and polarization of the quasar PKS 0405-385 observed in 1996 are subject to a correlation analysis, from which characteristic time scales and amplitudes are derived. The variations are interpreted as interstellar scintillations. The cm wavelength observations are in the weak scintillation regime for which models for the various auto- and cross-correlations of the Stokes parameters are derived and fitted to the observations. These are well modelled by interstellar scintillation (ISS) of a 30 by 22 micro-as source, with about 180 degree rotation of the polarization angle along its long dimension. This success in explaining the remarkable intra-day variations (IDV)in polarization confirms that ISS gives rise to the IDV in this quasar. However, the fit requires the scintillations to be occurring much closer to the Earth than expected according to the standard model for the ionized interstellar medium (IISM). Scattering at distances in the range 3-30 parsec are required to explain the observations. The associated source model has a peak brightness temperature near 2.0 10^{13}K, which is about twenty-five times smaller than previously derived for this source. This reduces the implied Doppler factor in the relativistic jet, presumed responsible to 10-20, high but just compatible with cm wavelength VLBI estimates for the Doppler factors in Active Galactic Nuclei (AGNs).Comment: 43 pages 15 figures, accepted for ApJ Dec 200

    Intra-day variability observations of S5 0716+714 over 4.5 years at 4.8 GHz

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    We aim to search for evidence of annual modulation in the time scales of the BL Lac object S5 0716+714. The intra-day variability (IDV) observations were carried out monthly from 2005 to 2009, with the Urumqi 25m radio telescope at 4.8 GHz. The source has shown prominent IDV as well as long-term flux variations. The IDV time scale does show evidence in favor of an annual modulation, suggesting that the IDV of 0716+714 is dominated by interstellar scintillation. The source underwent a strong outburst phase between mid-2008 and mid-2009; a second intense flare was observed in late 2009, but no correlation between the total flux density and the IDV time scale is found, implying that the flaring state of the source does not have serious implications for the general characteristics of its intra-day variability. However, we find that the inner-jet position angle is changing throughout the years, which could result in an annual modulation noise in the anisotropic ISS model fit. There is also an indication that the lowest IDV amplitudes (rms flux density) correspond to the slowest time scales of IDV, which would be consistent with an ISS origin of the IDV of 0716+714.Comment: 6 pages, 7 figures, accepted for publication in A&A; corrected typos in Table

    Untangling the Conceptual Isssues Raised in Reydon and Scholz’s Critique of Organizational Ecology and Darwinian Populations

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    Reydon and Scholz raise doubts about the Darwinian status of organizational ecology by arguing that Darwinian principles are not applicable to organizational populations. Although their critique of organizational ecology’s typological essentialism is correct, they go on to reject the Darwinian status of organizational populations. This paper claims that the distinction between replicators and interactors, raised in modern philosophy of biology but not discussed by Reydon and Scholz, points the way forward for organizational ecologists. It is possible to conceptualise evolving Darwinian populations providing the inheritance mechanism is appropriately specified. By this approach, adaptation and selection are no longer dichotomised, and the evolutionary significance of knowledge transmission is highlightedPeer reviewe
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