56,361 research outputs found
Regional heterogeneity and fertility behaviour in India
This paper examines regional heterogeneity both from statistical
and cartographic perspectives, using factor analysis of non-demographic
data, models of fertility determinants and district-wise mapping to test
out the presence of regional clustering. Regional analysis reveals that
economic, social and health indicators display spatial patterns as strong
as fertility rates. All recent models of fertility incorporate a significant
geographical component (using dummy regional variables or autocorrelation
measurements). The map of fertility decline spreading along
culturally and spatially contiguous regions also suggests that diffusion
mechanisms may play an independent role in the spread of new
reproductive behaviour (small family norm). Though diffusion per se,
no real explanation for the fast decline of fertility in Southern or Coastal
India (what would then be the cause of diffusion in the first place?), it
would definitely be important to understand how these mechanisms are
facilitated by social and cultural homogeneity or by regional policies.
JEL Classification: J 11, J 13, I12, I 28
Key Words : Fertility, South India, diffusion, heterogeneity, family
planning, reproductive behaviour, coastal India, infant
mortality
The Local Emergence and Global Diffusion of Research Technologies: An Exploration of Patterns of Network Formation
Grasping the fruits of "emerging technologies" is an objective of many
government priority programs in a knowledge-based and globalizing economy. We
use the publication records (in the Science Citation Index) of two emerging
technologies to study the mechanisms of diffusion in the case of two innovation
trajectories: small interference RNA (siRNA) and nano-crystalline solar cells
(NCSC). Methods for analyzing and visualizing geographical and cognitive
diffusion are specified as indicators of different dynamics. Geographical
diffusion is illustrated with overlays to Google Maps; cognitive diffusion is
mapped using an overlay to a map based on the ISI Subject Categories. The
evolving geographical networks show both preferential attachment and
small-world characteristics. The strength of preferential attachment decreases
over time, while the network evolves into an oligopolistic control structure
with small-world characteristics. The transition from disciplinary-oriented
("mode-1") to transfer-oriented ("mode-2") research is suggested as the crucial
difference in explaining the different rates of diffusion between siRNA and
NCSC
Mapping the Evolution of "Clusters": A Meta-analysis
This paper presents a meta-analysis of the âcluster literatureâ contained in scientific journals from 1969 to 2007. Thanks to an original database we study the evolution of a stream of literature which focuses on a research object which is both a theoretical puzzle and an empirical widespread evidence. We identify different growth stages, from take-off to development and maturity. We test the existence of a life-cycle within the authorships and we discover the existence of a substitutability relation between different collaborative behaviours. We study the relationships between a âspatialâ and an âindustrialâ approach within the textual corpus of cluster literature and we show the existence of a âpredatoryâ interaction. We detect the relevance of clustering behaviours in the location of authors working on clusters and in measuring the influence of geographical distance in co-authorship. We measure the extent of a convergence process of the vocabulary of scientists working on clusters.Cluster, Life-Cycle, Cluster Literature, Textual Analysis, Agglomeration, Co-Authorship
Batch kernel SOM and related Laplacian methods for social network analysis
Large graphs are natural mathematical models for describing the structure of
the data in a wide variety of fields, such as web mining, social networks,
information retrieval, biological networks, etc. For all these applications,
automatic tools are required to get a synthetic view of the graph and to reach
a good understanding of the underlying problem. In particular, discovering
groups of tightly connected vertices and understanding the relations between
those groups is very important in practice. This paper shows how a kernel
version of the batch Self Organizing Map can be used to achieve these goals via
kernels derived from the Laplacian matrix of the graph, especially when it is
used in conjunction with more classical methods based on the spectral analysis
of the graph. The proposed method is used to explore the structure of a
medieval social network modeled through a weighted graph that has been directly
built from a large corpus of agrarian contracts
Mining a medieval social network by kernel SOM and related methods
This paper briefly presents several ways to understand the organization of a
large social network (several hundreds of persons). We compare approaches
coming from data mining for clustering the vertices of a graph (spectral
clustering, self-organizing algorithms. . .) and provide methods for
representing the graph from these analysis. All these methods are illustrated
on a medieval social network and the way they can help to understand its
organization is underlined
Review of current practices in recording road traffic incident data: with specific reference to spatial analysis and road policing policy
Road safety involves three major components: the road system, the human factor and the vehicle element.
These three elements are inter-linked through geo-referenced traffic events and provide the basis for road
safety analyses and attempts to reduce the number of road traffic incidents and improve road safety.
Although numbers of deaths and serious injuries are back to approximately the 1950s levels when there
were many fewer vehicles on the road, there are still over 100 fatalities or serious injuries every day, and
this is a considerable waste of human capital. It is widely acknowledged that the location perspective is the
most suitable methodology by which to analyse different traffic events, where by in this paper, I will
concentrating on the relationship between road traffic incidents and traffic policing. Other methods include
studying road and vehicle engineering and these will be discussed later. It is worth noting here that there is
some division within the literature concerning the definitions of âaccidentâ and âincidentâ. In this paper I
will use âincidentâ because it is important to acknowledge a vast majority of âroad accidentsâ are in fact
crimes. However I will use the term âaccidentâ where it is referred to in the literature or relevant reports. It
is important to mention here that a road traffic accident can be defined as âthe product of an unwelcome
interaction between two or more moving objects, or a fixed and moving objectâ (Whitelegg 1986). Road
safety and road incident reduction relates to many other fields of activity including education, driver
training, publicity campaigns, police enforcement, road traffic policing, the court system, the National
Health Service and Vehicle engineering.
Although the subject of using GIS to analyse road traffic incidents has not received much academic
attention, it lies in the field of crime mapping which is becoming increasingly important. It is clear that
studies have been attempted to analyse road traffic incidents using GIS are increasingly sophisticated in
terms of hypotheses and statistical technique (for example see Austin, Tight and Kirby 1997). However it is
also clear that there is considerable blurring of boundaries and the analysis of road accidents sits
uncomfortably in crime mapping. This is due to four main reasons:
- Road traffic incidents are associated with road engineering, which is concerned with generic
solutions while road traffic analysis is about sensitivity to particular contexts.
- Not all road traffic incidents are crimes
- It is not just the police who have an interest in reducing road traffic incidents, other partners
include local authorities, hospitals and vehicle manufacturers
- The management of road traffic incidents is not just confined to the police
GIS has been used for over thirty years however it has only been recently been used in the field of
transportation. The field of transportation has come to embrace Geographical Information Systems as a keytechnology to support its research and operational need. The acronym GIS-T is often employed to refer to
the application and adaptation of GIS to research, planning and management in transportation. GIS-T
covers a broad arena of disciplines of which road traffic incident detection is just one theme. Others include
in vehicle navigation systems.
Initially it was only used to ask simple accident enquiries such as depicting the relative incidence of
accidents in wet weather or when there is no street lighting, or to flag high absolute or relative incidences
of accidents (see Anderson 2002). Recently however there has been increased acknowledgement that there
is a requirement to go beyond these simple questions and to extend the analyses. It has been widely claimed
by academics and the police alike that knowing where road accidents occur must lead to better road
policing, in order to ensure that road policing becomes better integrated with other policing activities. This
paper will be used to explore issues surrounding the analysis of road traffic accidents and how GIS
analysts, police and policy makers can achieve a better understanding of road traffic incidents and how to
reduce them.
For the purpose of this study I will be trying to achieve a broader overview of the aspects concerning road
accident analysis with a strong emphasis on data quality and accuracy with concern to GIS analysis. Data
quality and accuracy are seen as playing a pivotal role in the road traffic management agenda because they assist the police and Local Authorities as to the specific location whereby management can be undertaken.
Part one will consider the introduction to road incidents and their relationship with geography and spatial
analysis and how this were initially applied to locating âhotspotsâ and the more recent theory of âaccident
migrationâ. Part two will address current data issues of the UK collection procedure. This section will pay
particular reference to geo-referencing and the implication of data quality on the procedure of analysing
road incidents using GIS. Part three addresses issues surrounding the spatial analysis of road traffic
incidents, including some techniques such as spatial autocorrelation, time-space geography and the
modifiable area unit problem. Finally part four looks at the role of effective road traffic policing and how
this can be achieved due to better understanding of the theory and issues arising from analysing road traffic
incidents. It will also look at the diffusion and use of GIS within the police and local authorities
The State of the Art in Cartograms
Cartograms combine statistical and geographical information in thematic maps,
where areas of geographical regions (e.g., countries, states) are scaled in
proportion to some statistic (e.g., population, income). Cartograms make it
possible to gain insight into patterns and trends in the world around us and
have been very popular visualizations for geo-referenced data for over a
century. This work surveys cartogram research in visualization, cartography and
geometry, covering a broad spectrum of different cartogram types: from the
traditional rectangular and table cartograms, to Dorling and diffusion
cartograms. A particular focus is the study of the major cartogram dimensions:
statistical accuracy, geographical accuracy, and topological accuracy. We
review the history of cartograms, describe the algorithms for generating them,
and consider task taxonomies. We also review quantitative and qualitative
evaluations, and we use these to arrive at design guidelines and research
challenges
The power of GIS language
I have been working now for 50 years â since
the foundation of Environmental Systems
Research Institute (Esri), in 1969 â on building
software tools that help different kinds of users
do their work better.
Some of this is daily management, some of it
is work flows but the power of GIS is the central
power, the heart of GIS is really remarkable. Itâs
almost magical to me. So, Iâm sort of
rediscovering myself and emphasising to all of
GIS users all over the world to make better
maps. Maps are about telling a story. Many of
the maps that users make are maps that donât tell
a story. There are lines and dots and a text and
graphic display but they are not leveraging the
power of this communication language. So I
think of maps as a kind of language and we have
photographs and paintings â these are graphic
expressions of reality but a map is much more
powerful and we need to treat it as the power
that it has
- âŠ