A survey on Human Mobility and its applications

Human Mobility has attracted attentions from different fields of studies such as epidemic modeling, traffic engineering, traffic prediction and urban planning. In this survey we review major characteristics of human mobility studies including from trajectory-based studies to studies using graph and network theory. In trajectory-based studies statistical measures such as jump length distribution and radius of gyration are analyzed in order to investigate how people move in their daily life, and if it is possible to model this individual movements and make prediction based on them. Using graph in mobility studies, helps to investigate the dynamic behavior of the system, such as diffusion and flow in the network and makes it easier to estimate how much one part of the network influences another by using metrics like centrality measures. We aim to study population flow in transportation networks using mobility data to derive models and patterns, and to develop new applications in predicting phenomena such as congestion. Human Mobility studies with the new generation of mobility data provided by cellular phone networks, arise new challenges such as data storing, data representation, data analysis and computation complexity. A comparative review of different data types used in current tools and applications of Human Mobility studies leads us to new approaches for dealing with mentioned challenges

Physical activity, obesity, and educational attainment in 50- to 70-year-old adults

Aim: The purpose of the study is to investigate, in subpopulations with varying levels of education, firstly, the extent to which older adults with an otherwise sedentary lifestyle perform simple everyday physical activities such as cycling for transport or taking a walk, and the extent to which older adults perform everyday physical activities in addition to exercise; and secondly, to explore correlations between physical activity and obesity. Methods: The study is based on a representative, Baden-Württemberg State Foundation-funded study in 50- to 70-year-old residents of Baden-Württemberg (n = 2,002). Results: Subjects who say they ride a bike for transport or take a walk are significantly more likely to exercise than subjects who do not walk or cycle regularly. This holds even after controlling for sociodemographic and lifestyle-relevant variables. However, the correlation between walking and exercise, and the positive correlation between walking and obesity, is retained only for subjects with a low level of education. Both for subjects with a low level of education and for subjects with a high level of education, multivariate analysis discloses a negative correlation between regular cycling and obesity. Conclusions: People who do not exercise regularly are also less active on a day-to-day basis and are less likely to take a walk or ride a bike for transport. Given the health-preserving effects attributed to leisure-time physical activity from a biological and medical point of view, it is particularly important to encourage older adults and disadvantaged sectors of the population to be more physically active

Self-organization of Nodes using Bio-Inspired Techniques for Achieving Small World Properties

In an autonomous wireless sensor network, self-organization of the nodes is essential to achieve network wide characteristics. We believe that connectivity in wireless autonomous networks can be increased and overall average path length can be reduced by using beamforming and bio-inspired algorithms. Recent works on the use of beamforming in wireless networks mostly assume the knowledge of the network in aggregation to either heterogeneous or hybrid deployment. We propose that without the global knowledge or the introduction of any special feature, the average path length can be reduced with the help of inspirations from the nature and simple interactions between neighboring nodes. Our algorithm also reduces the number of disconnected components within the network. Our results show that reduction in the average path length and the number of disconnected components can be achieved using very simple local rules and without the full network knowledge.Comment: Accepted to Joint workshop on complex networks and pervasive group communication (CCNet/PerGroup), in conjunction with IEEE Globecom 201

Achieving Small World Properties using Bio-Inspired Techniques in Wireless Networks

It is highly desirable and challenging for a wireless ad hoc network to have self-organization properties in order to achieve network wide characteristics. Studies have shown that Small World properties, primarily low average path length and high clustering coefficient, are desired properties for networks in general. However, due to the spatial nature of the wireless networks, achieving small world properties remains highly challenging. Studies also show that, wireless ad hoc networks with small world properties show a degree distribution that lies between geometric and power law. In this paper, we show that in a wireless ad hoc network with non-uniform node density with only local information, we can significantly reduce the average path length and retain the clustering coefficient. To achieve our goal, our algorithm first identifies logical regions using Lateral Inhibition technique, then identifies the nodes that beamform and finally the beam properties using Flocking. We use Lateral Inhibition and Flocking because they enable us to use local state information as opposed to other techniques. We support our work with simulation results and analysis, which show that a reduction of up to 40% can be achieved for a high-density network. We also show the effect of hopcount used to create regions on average path length, clustering coefficient and connectivity.Comment: Accepted for publication: Special Issue on Security and Performance of Networks and Clouds (The Computer Journal

Caracterização e quantificação do sistema poroso em rochas básicas e ácidas do Grupo Serra Geral

A Província Basáltica Continental Paraná-Etendeka registra o vulcanismo fissural que precedeu a fragmentação do Gondwana no Cretáceo. Este imenso vulcanismo denominado no Brasil de Grupo Serra Geral tem sido investigado especialmente por estudos geoquímicos e geocronológicos. Estudos recentes no Rio Grande do Sul incluíram o mapeamento de detalhe e associação de litofácies como ferramentas pra a construção estratigráfica deste vulcanismo. Descobertas de hidrocarbonetos em bacias vulcanossedimentares promoveram o estudo das relações estratigráficas e propriedades petrofísicas de sistemas vulcânicos, sendo que devido aos processos primários e secundários, estas rochas geralmente são descritas como sistemas porosos complexos. Na área de estudo, porção sul da Província, há a ocorrência de derrames básicos e ácidos sendo possível caracterizar e quantificar o espaço poroso de amostras de diferentes morfologias e também em diferentes zonas internas de derrames. A quantificação das propriedades petrofísicas comumente é realizada a partir de métodos experimentais, como porosímetro e permeâmetro. Através destas técnicas, as amostras estudadas evidenciaram diferentes valores de propriedades petrofísicas, sendo que a porosidade apresentou uma variação entre 0,11 e 13,08% e a permeabilidade, para a maioria das amostras, ficou abaixo de 0,0004mD. Já a microtomografia de raios-X, técnica recente no estudo de rochas, permite a caracterização tridimensional do sistema poroso através de imagens. A partir desta caracterização, constatou-se que os valores de porosidade obtidos em três diferentes resoluções de imagens não alcançaram os valores obtidos pelo porosímetro, o que pode ser devido à limitação do método, mas que também evidencia que o sistema poroso das rochas vulcânicas do Grupo Serra Geral é multi-escalar. As heterogeneidades do sistema poroso destas rochas foram observadas principalmente quando são comparados litotipos vulcanoclásticos e coerentes, e diferentes zonas internas de derrames. Além disso, a influência de processos secundários também favorece a complexidade do sistema poroso.The Paraná-Etendeka Volcanic Province records the fissural volcanism that preceded the Gondwana fragmentation during Cretaceous. This huge volcanism is denominated as Grupo Serra Geral in Brazil and has been investigated specially by geochemical and geochronological studies. Recently, researches in Rio Grande do Sul have focused on a detailed mapping and lithofacies association as tools for the construction of the volcanic stratigraphic framework. The discovery of hydrocarbon in volcano-sedimentary basins promoted the study of stratigraphical relations and petrophysical properties of volcanic systems. These features are generally described in volcanic rocks as complex porous systems due to primary and secondary processes. In the south portion of the Province, the occurrence of basic and acid flows enables the characterization and quantification of the pore space in samples from different flow morphologies and different internal flow zones. The quantification of petrophysical properties is commonly executed through experimental methods, such as the porosimeter and permeameter. Through these techniques, the studied samples demonstrated different petrophysical properties. The porosity displays values ranging from 0,11 and 13,08%, and permeability remains lower than 0,0004mD. The X-ray microtomography is a recent technique in rock studies that allows the tridimensional characterization of the porous system through images. Using this technique, the porosity values obtained with three different image resolutions do not reach the results calculated by the porosimeter. These records can be explained due to the method limitation and indicate a multi-scalar porous system for the rocks of Grupo Serra Geral. The heterogeneity of these rocks was mainly observed when lava flows and volcaniclastic samples were compared, as well as different internal zones of the flows. Additionally, the influence of secondary processes also contributes for the complexity of the pore system

Caracterização Petrográfica e Petrofísica de Litofácies Vulcânicas da Formação Serra Geral

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Filosofia e Ciências Humanas. Geologia.Reservoirs in volcanic rocks have been demonstrating potential to exploration of hydrocarbon resources, since some productive basins in the world have intercalations of volcanic rocks and subvolcanic intrusions, especially those formed in rift areas. Basalt lava flow, dikes and sills can act as reservoirs rocks or cap rocks, depending on petrophysics characteristics, alteration level and amount of fractures. Furthermore, it can also provide enough heat to accelerate the maturation of organic matter. For these reasons, the study of analogue volcanic systems is fundamental to understanding reservoirs in volcano- sedimentary systems that are located in offshore basins. The Paraná-Etendeka magmatic province is one of the biggest continental basalt provinces in the world, with an area of approximately 1.300.00 km2, situated in South America and Africa (Namibia). This province is constituted mainly by basic volcanic rocks and intrusions and is called Serra Geral Formation in Brazil. The goal of this work is to study the petrographic and petrophysical characteristics of three volcanic facies (pahoehoe- vesicular basalt, rubbly pahoehoe- massive escoriaceous breccia and rubbly pahoehoe- porous escoriaceous breccia) of the Serra Geral Formation, considering that the characterization of porous media is crucial in reservoirs evaluation. The X- ray microtomography technique, used in petrophysical characterization, has been gaining importance in reservoir characterization because it enables a qualitative and quantitative three- dimensional investigation of porous media. The results of this work have demonstrated that this technique allow a good characterization of volcanic rocks, nevertheless it should be better investigated (as seen in sedimentary rocks). The results also have established that the lithofacies studied have presented heterogeneous petrophysical parameters as well as different features on petrographic analysis.Reservatórios em rochas vulcânicas vêm sendo estudados e tem demonstrado potencial para exploração de hidrocarbonetos, já que muitas bacias produtoras no mundo contêm intercalações de rochas vulcânicas e intrusões subvulcânicas, especialmente aquelas formadas em áreas de rifte. Derrames de basaltos, diques e soleiras podem atuar como rochas-reservatórios ou selantes, dependendo das características petrofísicas, grau de alteração e fraturamento, além de também poderem fornecer calor suficiente para acelerar a maturação da matéria orgânica. Além do potencial de exploração de hidrocarbonetos em rochas vulcânicas e sedimentares associadas, o estudo de sistemas vulcânicos análogos também é fundamental para o entendimento de reservatórios em sistemas vulcanossedimentares que se encontram em bacias offshore. A Província Magmática Paraná-Etendeka é uma das maiores províncias de basaltos continentais no mundo com uma área de cerca de 1.300.00 km2 aflorante na América do Sul e África (Namíbia). Esta província é constituída principalmente por rochas vulcânicas e intrusivas básicas e no Brasil é denominada de Formação Serra Geral. O objetivo deste trabalho é o estudo de três litofácies vulcânicas (basalto vesiculado - pahoehoe, brecha escoriácea maciça - rubbly pahoehoe e brecha escoriácea porosa - rubbly pahoehoe) da Fm. Serra Geral quanto à caracterização petrográfica e petrofísica, já que a caracterização do sistema poroso é fundamental na avaliação de reservatórios. A técnica da microtomografia de raios X, utilizada na caracterização petrofísica, vem se intensificando na caracterização de rochas reservatório uma vez que permite a investigação qualitativa e quantitativa tridimensional do sistema poroso. Os resultados deste trabalho demonstram que a técnica da microtomografia de raios X permite uma boa caracterização do sistema poroso de rochas vulcânicas, mas que ainda deve ser aperfeiçoada (a exemplo dos estudos nas rochas sedimentares). Os resultados também evidenciam que as três litofácies estudadas apresentam valores heterogêneos das propriedades petrofísicas, bem como diferentes características na análise petrográfica

Les premiers recensements au Sénégal et l’évolution démographique : partie I: présentation des documents

La documentation démographique concernant les populations rurales de l’Ouest-Africain ne s’est vraiment développée qu’à une époque très récente. On remarque une disparité entre les données relatives aux villes et escales, et celles qui ont trait à la situation rurale. La population urbaine a pu faire l’objet de véritables études démographiques, dès avant les indépendances, alors qu’en milieu rural, on s’est contenté des dénombrements effectués à des fins administratives et fiscales