14,295 research outputs found
Assessing texture pattern in slum across scales: an unsupervised approach
According to the Global Report on Human Settlements (United Nations, 2003), almost 1 billion people (32% of the
world âs population) live in squatter settlements or slums. Recently, the perception of these settlements has changed, from
harmful tumours which would spread around sickly and unhealthy cities, to a new perspective that interpret them as
social expressions of more complex urban dynamics. However, considering a report from UNCHS - United Nations
Center for Human Settlements, in relation to illegal and disordered urbanisation issue, some of the main challenges faced
by cities are related to mapping and registering geographic information and social data spatial analysis. In this context, we
present, in this paper, preliminary results from a study that aims to interpret city from the perspective of urban texture,
using for this purpose, high resolution remote sensing images. We have developed analytic experiments of "urban tissue"
samples, trying to identify texture patterns which could (or could not) represent distinct levels of urban poverty associated
to spatial patterns. Such analysis are based on some complex theory concepts and tools, such as fractal dimension and
lacunarity. Preliminary results seems to suggest that the urban tissue is fractal by nature, and from the distinct texture
patterns it is possible to relate social pattern to spatial configuration, making possible the development of methodologies
and computational tools which could generate, via satellite, alternative and complementary mapping and classifications
for urban poverty
An exploration of choice in heroin addiction: âAn interpretative phenomenological analysis of a small sample of people in recoveryâ
This research investigates the subjective experience of choice in heroin addiction. The aims were to investigate the perceived degree of control participants felt they had in relation to heroin use, and the impact this had on their lives. The idea of choice is the main aspect distinguishing the free-will model from the medical model in the field. Seven participants were interviewed for this study, two females and five males. The participants were recovering heroin addicts with length of recovery varying from 2 months to 7 years from different ethnicities and socially disadvantaged backgrounds. These were recruited and interviewed in two different 12 Step Model recovery centres. The analysis adopted Interpretative Phenomenological Analysis (IPA) as its qualitative approach as this was found to be most suitable for the experiential focus of this studyâs question. The main themes were; ânot belongingâ, âheroin both gives and robs oneâs identityâ and âlack of control leads to recovery.â This research illustrates the limited choices the participants faced in their lives and how change was only possible through acknowledging oneâs emotional response to a particular situation, rather than a cognitive response; whilst the participants took drugs to numb their emotions, it became impossible to make different choices in their lives. The importance of issues of identity, belonging and trauma were findings consistent with previous literature in the field of addiction. Recommendations for future research focus on a mixed methodology research showing the link between emotions and choices in reframing someoneâs experience of addiction. Further recommendations would be a focused study on the impact of time in addiction and how the existential approach can contribute to enhancing treatment choices. By looking at how the existential phenomenological approach contributes to the field this research highlights possible preventative issues. The lack of choice is not attributed to disease but rather to a complex set of circumstances illustrated by the participantâs interviewed. The implication for those working in the field is to open up choices by focusing on how emotions are the primary way of changing and reinterpreting oneâs life
Cost optimization of singly and doubly reinforced concrete beams with EC2-2001
A model for the optimal design of rectangular reinforced concrete sections is presented considering the stressâstrain diagrams described in EC2-2001 and MC90. The following expressions are developed: economic bending moment; optimal area of steel and optimal steel ratio between upper and lower steel. All the expressions are in nondimensional form. The present model is applied to four different classes of concrete described in MC90. It is concluded that in nondimensional form the equations are nearly coincident for both singly and doubly reinforcement. It is also concluded that the ultimate strain for concrete in the compression zone, ecm, lies between the strain for peak stress ec1 and the ultimate strain ecu. This result is relevant once that the maximum moment is obtained for this value, and not the value ecu, as defined in EC2-2001. Cost optimization is implemented in the code and compared with other optimum models based on the ultimate design of ACI
Disorder-induced double resonant Raman process in graphene
An analytical study is presented of the double resonant Raman scattering
process in graphene, responsible for the D and D features in the
Raman spectra. This work yields analytical expressions for the D and
D integrated Raman intensities that explicitly show the dependencies
on laser energy, defect concentration, and electronic lifetime. Good agreement
is obtained between the analytical results and experimental measurements on
samples with increasing defect concentrations and at various laser excitation
energies. The use of Raman spectroscopy to identify the nature of defects is
discussed. Comparison between the models for the edge-induced and the
disorder-induced D band intensity suggests that edges or grain boundaries can
be distinguished from disorder by the different dependence of their Raman
intensity on laser excitation energy. Similarly, the type of disorder can
potentially be identified not only by the intensity ratio
, but also by its laser energy
dependence. Also discussed is a quantitative analysis of quantum interference
effects of the graphene wavefunctions, which determine the most important
phonon wavevectors and scattering processes responsible for the D and
D bands.Comment: 10 pages, 4 figure
Novel magnetic orderings in the kagome Kondo-lattice model
We consider the Kondo-lattice model on the kagome lattice and study its
weak-coupling instabilities at band filling fractions for which the Fermi
surface has singularities. These singularites include Dirac points, quadratic
Fermi points in contact with a flat band, and Van Hove saddle points. By
combining a controlled analytical approach with large-scale numerical
simulations, we demonstrate that the weak-coupling instabilities of the
Kondo-lattice model lead to exotic magnetic orderings. In particular, some of
these magnetic orderings produce a spontaneous quantum anomalous Hall state.Comment: 15 pages, 11 figure
On the stability of spacelike hypersurfaces
In this paper we study the strong stability of spacelike hypersurfaces with
constant -th mean curvature in Generalized Robertson-Walker spacetimes of
constant sectional curvature. In particular, we treat the case in which the
ambient spacetime is the de Sitter space
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