7,764 research outputs found
Internal Migration and Regional Population Dynamics in Europe: Norway Case Study
This paper reports on internal migration and regional population dynamics in Norway. It examines internal migration patterns and trends in two years, 1984 and 1994, and compares them.
Norway's population maintains relatively high population growth by European standards, fuelled by continuing natural increase and net migration from outside the country. About half of Norway's municipalities lost population in aggregate over the 1984 to 1994. These municipalities are concentrated in the Centre-North and interior of southern Norway. There is evidence that communities with the lowest densities and least centrality are losing population through internal migration.
Although the direction of migration is towards denser and more central places, this is a product mainly of the migration of young people when the migration streams are broken down by age, the resulting tales show that the largest urban areas are experiencing net losses from middle age and upwards. There is little direct evidence of net positive migration flows to rural remote areas for the population as a whole. Migration flows out of the Oslo region are to other municipalities within commuting range. This deconcentration should therefore be identified as extended suburanisation rather than counter-urbanisation.
Throughout the current report the role of life course stage in influencing the direction of migration has been stressed. Most often the overall pattern of population shifts conceal very different flow structures for family migrants, young adults, older workers, retirees and the elderly. In this respect internal migration dynamics in Norway strongly resemble those in other West European countries.
Economic factors have an important influence on migration patterns. Municipalities with an economic concentration in service industries attract internal migrants while those specialised in primary industry suffer migration outflows consequent on the decline of or productivity improvements in their economic activities. There is a strong gradient of increasing net outflows with increasing levels of unemployment
EEF: Exponentially Embedded Families with Class-Specific Features for Classification
In this letter, we present a novel exponentially embedded families (EEF)
based classification method, in which the probability density function (PDF) on
raw data is estimated from the PDF on features. With the PDF construction, we
show that class-specific features can be used in the proposed classification
method, instead of a common feature subset for all classes as used in
conventional approaches. We apply the proposed EEF classifier for text
categorization as a case study and derive an optimal Bayesian classification
rule with class-specific feature selection based on the Information Gain (IG)
score. The promising performance on real-life data sets demonstrates the
effectiveness of the proposed approach and indicates its wide potential
applications.Comment: 9 pages, 3 figures, to be published in IEEE Signal Processing Letter.
IEEE Signal Processing Letter, 201
Studying the kinematic asymmetries of disks and post-coalescence mergers using a new `kinemetry' criterion
We have obtained VIMOS/VLT optical integral field spectroscopy (IFS) data for
a sample of 4 LIRGs which have been selected at a similar distance ( 70
Mpc) to avoid relative resolution effects. They have been classified in two
groups (isolated disk and post-coalescence mergers) according to their
morphology. The method (developed by Krajnovic and coworkers) is
used to characterize the kinematic properties of these galaxies and to discuss
new criteria for distinguishing their status. We present and discuss new
kinematic maps (i.e., velocity field and velocity dispersion) for these four
galaxies. The morphological and kinematic classifications of these systems are
consistent, with disks having lower kinematic asymmetries than post-coalescence
mergers. We then propose and discuss a new kinematic criterion to differentiate
these two groups. This criterion distinguishes better these two categories and
has the advantage of being less sensitive to angular resolution effects.
According to the previous criteria,the present post-coalescence systems would
have been classified as disks. This indicates that the separation of disks from
mergers is subjective to the definition of `merger'. It also suggests that
previous estimates of the merger/disk ratio could have been underestimated, but
larger samples are necessary to establish a firmer conclusion.Comment: 15 figures, 19 page
Twin subgraphs and core-semiperiphery-periphery structures
A standard approach to reduce the complexity of very large networks is to
group together sets of nodes into clusters according to some criterion which
reflects certain structural properties of the network. Beyond the well-known
modularity measures defining communities, there are criteria based on the
existence of similar or identical connection patterns of a node or sets of
nodes to the remainder of the network. A key notion in this context is that of
structurally equivalent or twin nodes, displaying exactly the same connection
pattern to the remainder of the network.
The first goal of this paper is to extend this idea to subgraphs of arbitrary
order of a given network, by means of the notions of T-twin and F-twin
subgraphs. This is motivated by the need to provide a systematic approach to
the analysis of core-semiperiphery-periphery (CSP) structures, a notion which
somehow lacks a formal treatment in the literature. The goal is to provide an
analytical framework accommodating and extending the idea that the unique
(ideal) core-periphery (CP) structure is a 2-partitioned K2. We provide a
formal definition of CSP structures in terms of core eccentricities and
periphery degrees, with semiperiphery vertices acting as intermediaries. The
T-twin and F-twin notions then make it possible to reduce the large number of
resulting structures by identifying isomorphic substructures which share the
connection pattern to the remainder of the graph, paving the way for the
decomposition and enumeration of CSP structures. We compute the resulting CSP
structures up to order six.
We illustrate the scope of our results by analyzing a subnetwork of the
network of 1994 metal manufactures trade. Our approach can be further applied
in complex network theory and seems to have many potential extensions
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