2,829 research outputs found
The impact and penetration of location-based services
Since the invention of digital technology, its development has followed an entrenched path ofminiaturisation and decentralisation with increasing focus on individual and niche applications. Computerhardware has moved from remote centres to desktop and hand held devices whilst being embedded invarious material infrastructures. Software has followed the same course. The entire process has convergedon a path where various analogue devices have become digital and are increasingly being embedded inmachines at the smallest scale. In a parallel but essential development, there has been a convergence ofcomputers with communications ensuring that the delivery and interaction mechanisms for computersoftware is now focused on networks of individuals, not simply through the desktop, but in mobilecontexts. Various inert media such as fixed television is becoming more flexible as computers and visualmedia are becoming one.With such massive convergence and miniaturisation, new software and new applications define the cuttingedge. As computers are being increasingly tailored to individual niches, then new digital services areemerging, many of which represent applications which hitherto did not exist or at best were rarely focusedon a mass market. Location based services form one such application and in this paper, we will bothspeculate on and make some initial predictions of the geographical extent to which such services willpenetrate different markets. We define such services in detail below but suffice it to say at this stage thatsuch functions involve the delivery of traditional services using digital media and telecommunications.High profile applications are now being focused on hand held devices, typically involving information onproduct location and entertainment but wider applications involve fixed installations on the desktop whereservices are delivered through traditional fixed infrastructure. Both wire and wireless applications definethis domain. The market for such services is inevitably volatile and unpredictable at this early stage but wewill attempt here to provide some rudimentary estimates of what might happen in the next five to tenyears.The ?network society? which has developed through this convergence, is, according to Castells (1989,2000) changing and re-structuring the material basis of society such that information has come todominate wealth creation in a way that information is both a raw material of production and an outcome ofproduction as a tradable commodity. This has been fuelled by the way technology has expanded followingMoore?s Law and by fundamental changes in the way telecommunications, finance, insurance, utilitiesand so on is being regulated. Location based services are becoming an integral part of this fabric and thesereflect yet another convergence between geographic information systems, global positioning systems, andsatellite remote sensing. The first geographical information system, CGIS, was developed as part of theCanada Land Inventory in 1965 and the acronym ?GIS? was introduced in 1970. 1971 saw the firstcommercial satellite, LANDSAT-1. The 1970s also saw prototypes of ISDN and mobile telephone and theintroduction of TCP/IP as the dominant network protocol. The 1980s saw the IBM XT (1982) and thebeginning of de-regulation in the US, Europe and Japan of key sectors within the economy. Finally in the 1990s, we saw the introduction of the World Wide Web and the ubiquitous pervasion of business andrecreation of networked PC?s, the Internet, mobile communications and the growing use of GPS forlocational positioning and GIS for the organisation and visualisation of spatial data. By the end of the 20thcentury, the number of mobile telephone users had reached 700 million worldwide. The increasingmobility of individuals, the anticipated availability of broadband communications for mobile devices andthe growing volumes of location specific information available in databases will inevitably lead to thedemand for services that will deliver location related information to individuals on the move. Suchlocation based services (LBS) although in a very early stage of development, are likely to play anincreasingly important part in the development of social structures and business in the coming decades.In this paper we begin by defining location based services within the context we have just sketched. Wethen develop a simple model of the market for location-based services developing the standard non-linearsaturation model of market penetration. We illustrate this for mobile devices, namely mobile phones in thefollowing sections and then we develop an analysis of different geographical regimes which arecharacterised by different growth rates and income levels worldwide. This leads us to speculate on theextent to which location based services are beginning to take off and penetrate the market. We concludewith scenarios for future growth through the analogy of GIS and mobile penetration
Quantifying Retail Agglomeration using Diverse Spatial Data
Newly available data on the spatial distribution of retail activities in cities makes it possible to build models formalized at the level of the single retailer. Current models tackle consumer location choices at an aggregate level and the opportunity new data offers for modeling at the retail unit level lacks an appropriate theoretical framework. The model we present here helps to address these issues. Based on random utility theory, we have built it around the idea of quantifying the role of floor-space and agglomeration in retail location choice. We test this model on the inner area of Greater London. The results are consistent with a super linear scaling of a retailer's attractiveness with its floorspace, and with an agglomeration effect approximated as the total retail floorspace within a 300 m radius from each shop. Our model illustrates many of the issues involved in testing and validating urban simulation models involving spatial data and its aggregation to different spatial scales
Random planar graphs and the London street network
In this paper we analyse the street network of London both in its primary and dual representation. To understand its properties, we consider three idealised models based on a grid, a static random planar graph and a growing random planar graph. Comparing the models and the street network, we find that the streets of London form a self-organising system whose growth is characterised by a strict interaction between the metrical and informational space. In particular, a principle of least effort appears to create a balance between the physical and the mental effort required to navigate the city
The envirome and the connectome: exploring the structural noise in the human brain associated with socioeconomic deprivation
Complex cognitive functions are widely recognized to be the result of a number of brain regions working together as large-scale networks. Recently, complex network analysis has been used to characterize various structural properties of the large scale network organization of the brain. For example, the human brain has been found to have a modular architecture i.e. regions within the network form communities (modules) with more connections between regions within the community compared to regions outside it. The aim of this study was to examine the modular and overlapping modular architecture of the brain networks using complex network analysis. We also examined the association between neighborhood level deprivation and brain network structure – modularity and grey nodes. We compared network structure derived from anatomical MRI scans of 42 middle-aged neurologically healthy men from the least (LD) and the most deprived (MD) neighborhoods of Glasgow with their corresponding random networks. Cortical morphological covariance networks were constructed from the cortical thickness derived from the MRI scans of the brain. For a given modularity threshold, networks derived from the MD group showed similar number of modules compared to their corresponding random networks, while networks derived from the LD group had more modules compared to their corresponding random networks. The MD group also had fewer grey nodes – a measure of overlapping modular structure. These results suggest that apparent structural difference in brain networks may be driven by differences in cortical thicknesses between groups. This demonstrates a structural organization that is consistent with a system that is less robust and less efficient in information processing. These findings provide some evidence of the relationship between socioeconomic deprivation and brain network topology
Random planar graphs and the London street network
In this paper we analyse the street network of London both in its primary and
dual representation. To understand its properties, we consider three idealised
models based on a grid, a static random planar graph and a growing random
planar graph. Comparing the models and the street network, we find that the
streets of London form a self-organising system whose growth is characterised
by a strict interaction between the metrical and informational space. In
particular, a principle of least effort appears to create a balance between the
physical and the mental effort required to navigate the city
Association of nursery and early school attendance with later health behaviours, biomedical risk factors, and mortality: evidence from four decades of follow-up of participants in the 1958 birth cohort study.
BACKGROUND: Although early life education for improved long-term health and the amelioration of socioeconomically generated inequalities in chronic disease is advocated in influential policy statements, the evidence base is very modest. AIMS: To address this dearth of evidence using data from a representative UK national birth cohort study. METHODS: The analytical sample comprised men and women in the 1958 birth cohort study with prospectively gathered data on attendance at nursery or primary school before the age of 5 years who had gone on to participate in social survey at 42 years (n=11 374), or a biomedical survey at 44/5 years of age (n=9210), or had data on vital status from 18 to 55 years (n=17 657). RESULTS: Relative to study members who had not attended nursery, in those who had, there was in fact a higher prevalence of smoking and high alcohol intake in middle age. Conversely, nursery attenders had more favourable levels of lung function and systolic blood pressure in middle age. This apparent association between nursery attendance and lower systolic blood pressure was confined to study members from more deprived social backgrounds of origin (P value for interaction 0.030). There was no apparent link between early school attendance and any behavioural or biological risk factor. Neither nursery nor early school attendance was clearly related to mortality risk. CONCLUSIONS: We found no clear evidence for an association of either attendance at nursery or primary school before the age of 5 years and health outcomes around four decades later
How simple rules determine pedestrian behavior and crowd disasters
With the increasing size and frequency of mass events, the study of crowd
disasters and the simulation of pedestrian flows have become important research
areas. Yet, even successful modeling approaches such as those inspired by
Newtonian force models are still not fully consistent with empirical
observations and are sometimes hard to calibrate. Here, a novel cognitive
science approach is proposed, which is based on behavioral heuristics. We
suggest that, guided by visual information, namely the distance of obstructions
in candidate lines of sight, pedestrians apply two simple cognitive procedures
to adapt their walking speeds and directions. While simpler than previous
approaches, this model predicts individual trajectories and collective patterns
of motion in good quantitative agreement with a large variety of empirical and
experimental data. This includes the emergence of self-organization phenomena,
such as the spontaneous formation of unidirectional lanes or stop-and-go waves.
Moreover, the combination of pedestrian heuristics with body collisions
generates crowd turbulence at extreme densities-a phenomenon that has been
observed during recent crowd disasters. By proposing an integrated treatment of
simultaneous interactions between multiple individuals, our approach overcomes
limitations of current physics-inspired pair interaction models. Understanding
crowd dynamics through cognitive heuristics is therefore not only crucial for a
better preparation of safe mass events. It also clears the way for a more
realistic modeling of collective social behaviors, in particular of human
crowds and biological swarms. Furthermore, our behavioral heuristics may serve
to improve the navigation of autonomous robots.Comment: Article accepted for publication in PNA
Description of Drip-Line Nuclei within Relativistic Mean-Field Plus BCS Approach
Recently it has been demonstrated, considering Ni and Ca isotopes as
prototypes, that the relativistic mean-field plus BCS (RMF+BCS) approach
wherein the single particle continuum corresponding to the RMF is replaced by a
set of discrete positive energy states for the calculation of pairing energy
provides a good approximation to the full relativistic Hartree-Bogoliubov (RHB)
description of the ground state properties of the drip-line neutron rich
nuclei. The applicability of RMF+BCS is essentially due to the fact that the
main contribution to the pairing correlations is provided by the low-lying
resonant states. General validity of this approach is demonstrated by the
detailed calculations for the ground state properties of the chains of isotopes
of O, Ca, Ni, Zr, Sn and Pb nuclei. The TMA and NL-SH force parameter sets have
been used for the effective mean-field Lagrangian. Comprehensive results for
the two neutron separation energy, rms radii, single particle pairing gaps and
pairing energies etc. are presented. The Ca isotopes are found to exhibit
distinct features near the neutron drip line whereby it is found that further
addition of neutrons causes a rapid increase in the neutron rms radius with
almost no increase in the binding energy, indicating the occurrence of halos. A
comparison of these results with the available experimental data and with the
recent continuum relativistic Hartree-Bogoliubov (RCHB) calculations amply
demonstrates the validity and usefulness of this fast RMF+BCS approach.Comment: 59 pages, 40 figure
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