Um estudo sobre a utilização do NFC: Tecnologia que tende a aproximar a Internet das Coisas da vida dos brasileiros

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ensino. Tecnologias da Informação e Comunicação.Internet das coisas (IoT) e NFC (Nead Field Communication) são assuntos que estão em alta em diversos países. O objetivo deste trabalho é identificar a concepção de entrevistado sobre a tecnologia NFC e propor algumas aplicações para aumentar a sua utilização no Brasil. Para identificar a concepção destes indivíduos foi aplicado um questionário para traçar o perfil do entrevistado, seu conhecimento sobre as tecnologias citadas e seu grau de aceitação sobre elas. Como resultado obteve-se que 43,3% dos entrevistados conhecem IoT e o NFC, sendo que 29,2% atua na área de tecnologias. Outra informação relevante é que a maioria dos entrevistados visualizam a utilização do NFC em inúmeras soluções futuras. Quanto a proposta de aplicações, foram elaborados três experimentos para auxiliar no cotidiano desses usuários. O resultado dos experimentos foram satisfatórios.Internet of Things (IoT) and NFC (Nead Field Communication) are subjects that are on the rise in several countries. The objective of this work is to identify the conception of Brazilian individuals about NFC technology and to propose some applications to increase their use in Brazil. To identify the conception of these individuals, a questionnaire was applied to draw the profile of the interviewee, their knowledge about the technologies cited and their degree of acceptance of them. As a result it was obtained that 43.3 % of people know IoT and NFC, with 29.2 % working in the area of technologies. Other relevant information is that most respondents view the use in NFC many future solution. Regarding the applications proposal, three exercises were elaborated to assist in the daily life of these users. The results of the experiments were satisfactory

Corrélats neuronaux de la conscience : apport de l'étude des modèles lésionnels du système nerveux central et périphérique

La conscience correspond à l'ensemble de capacités cognitives qui permettent à un individu d'acquérir et de partager son savoir avec autrui. D'un point de vue théorique, on peut distinguer deux composantes élémentaires dans ce concept: un niveau (i.e. vigilance) et un contenu (i.e. informations intégrées par l'individu). À son tour, le contenu conscient, fait référence à l'élaboration des notions distinctes de soi et du monde extérieur. En suivant une demarche anatomoclinique, centrée sur l'étude des modèles lésionnels du système nerveux central et périphérique, nous avons eu pour objectif la caractérisation des substrats neuronaux de chacune de ces composantes. Premièrement, nous nous sommes intéressés aux mécanismes impliqués dans l'emergence d'un contenu conscient à partir d'un niveau de conscience. Pour cela nous avons étudié de manière comparative en TEP H2O15 les cartes de débit sanguin cérébral au repos et lors d'une stimulation proprioceptive, chez des sujets sains et des patients en état neurologique végétatif (ENV). Nos résultats soulignent le rôle de la Formation Réticulée Activatrice Ascendante (FRAA) dans le maintien du niveau de conscience et du Cortex Postéro-Médian (CPM) dans l'élaboration de son contenu. Une deconnexion fonctionnelle entre ces structures semble associée au tableau clinique d'ENV. Ces éléments sont en accord avec les modèles théoriques qui corrèlent l'apparition de la conscience à la diffusion synchrone des informations au sein d'un réseau neuronal distribué. De manière complémentaire, nous avons étudié les processus liés à l'élaboration de la notion de soi à partir des representations motrices. À l'aide d'un modèle de déafférentation périphérique par anesthésie locorégionale (ALR), nous avons caractérisé dans ce contexte un ensemble d'illusions peceptives analogues à celles décrites chez les patients amputés. En effet, l'ALR semble être à l'origine de distorsions perceptives de taille/forme, de posture et de mouvement, dont l'apparition est corrélée avec la survenue du déficit proprioceptif. Parallèlement, nous avons analysé les performances des sujets sains bénéficiant d'une ALR du membre supérieur au décours d'une tâche de reconnaissance bimanuelle. Les résultats obtenus suggèrent que (i) la reconnaissance bimanuelle implique la simulation mentale des mouvements des mains, (ii) les representations centrales sous-jacentes sont modifiées rapidement par l'ALR, (iii) le substrat neuronal de l'image du corps recruté par cette tâche est capable d'intègrer des informations polymodales. Nos résultats apportent des éléments nouveaux concernant l'activité cérébrale résiduelle des sujets cérébrolésé et soulignent l'importance des connexions cérébrales nécessaires à l'élaboration d'une expérience consciente. L'étude du phénomène de membre fantôme induit par l'ALR constitue une approche originale des mécanismes impliqués dans l'émergence de la notion de soi. Cette procédure, actuellement dédiée à un usage exclusivement anesthésique, pourrait constituer dans un avenir proche, un nouvel outil de modulation thérapeutique des phénomènes de plasticité cérébrale adaptativeConsciousness is a multifaceted concept, which can be divided in two main components: arousal (i.e. level of consciousness) and awareness (i.e. the contents of consciousness). In turn, awareness can be divided in two elementary units: external and self-awareness. Here, we propose that disorders of consciouness, associated to brain or peripheral nervous injuries, are a privileged way to investigate the links between these components and their related neural mechanisms. On the basis of H2 O15 PET measurement of cerebral blood flow during rest or during a sensory stimulus, we comparatively analysed the level of interplay which exists between arousal and awareness in healthy subjects and in severely brain-injured patients in a vegetative state. Our results highlighted the role of two major areas: the Ascending Reticular Activating System (ARAS), and the Posteromedial cortex (PMC): one allowing conscious access to external stimuli and the another one, allowing self-referential processes. We demonstrated for the first time, that the Ascending Reticular Activating System (ARAS), whose activity was functionally correlated to that of the PMC in controls, showed no functional correlation with it in PVS patients. This data emphasizes the functional link between cortices and brainstem in the genesis of perceptual awareness and strengthens the hypothesis that consciousness is based on a widespread neural network. Otherwise, we studied generation and updating of self-awareness from peripheral inputs in a model of acute deafferentation induced by regional anesthesia (RA). First, we described that RA induces a set of perceptual illusion that are similar to the phantom limb sensations identified in amputees. RA-induced size, shape, postural and kinesthetic misperceptions for which the onset seems strongly related to an alteration of proprioception. Second, we used a visual left/right hand judgement task, implicitly recruiting motor imagery processes in patients receiving upper limb RA. Results suggest that (i) the right/left judgement task involves mental simulation of hand movements, (ii) the underlying mental representations and their neural substrates are subject to acute alterations following RA, (iii) brain regions supporting body image representations are modulated in a cross-modal way. Our data provide new insights about residual brain activity in severely brain-injured patients and the elaboration of a content of consciousness from a level of arousal. Looking at the phantom limb phenomena induced by RA, constitutes a novel approach to the study of the Self, and could pave the way to further studies assessing RA modulation of afferent inputs in the neurorehabilitation contex

Graph Constructions for the Contact Process with a Prescribed Critical Rate

We construct graphs (trees of bounded degree) on which the contact process has critical rate (which will be the same for both global and local survival) equal to any prescribed value between zero and λc(Z), the critical rate of the one-dimensional contact process. We exhibit both graphs in which the process at this target critical value survives (locally) and graphs where it dies out (globally).publishedVersio

Graph constructions for the contact process with a prescribed critical rate

We construct graphs (trees of bounded degree) on which the contact process has critical rate (which will be the same for both global and local survival) equal to any prescribed value between zero and $\lambda_c(\mathbb{Z})$, the critical rate of the one-dimensional contact process. We exhibit both graphs in which the process at this target critical value survives (locally) and graphs where it dies out (globally).Comment: 31 pages, 1 figur

Multiple time scales and the empirical models for stochastic volatility

The most common stochastic volatility models such as the Ornstein-Uhlenbeck (OU), the Heston, the exponential OU (ExpOU) and Hull-White models define volatility as a Markovian process. In this work we check of the applicability of the Markovian approximation at separate times scales and will try to answer the question which of the stochastic volatility models indicated above is the most realistic. To this end we consider the volatility at both short (a few days) and long (a few months)time scales as a Markovian process and estimate for it the coefficients of the Kramers-Moyal expansion using the data for Dow-Jones Index. It has been found that the empirical data allow to take only the first two coefficients of expansion to be non zero that define form of the volatility stochastic differential equation of Ito. It proved to be that for the long time scale the empirical data support the ExpOU model. At the short time scale the empirical model coincides with ExpOU model for the small volatility quantities only.Comment: 19 pages, 6 figure

Underlying Dynamics of Typical Fluctuations of an Emerging Market Price Index: The Heston Model from Minutes to Months

We investigate the Heston model with stochastic volatility and exponential tails as a model for the typical price fluctuations of the Brazilian S\~ao Paulo Stock Exchange Index (IBOVESPA). Raw prices are first corrected for inflation and a period spanning 15 years characterized by memoryless returns is chosen for the analysis. Model parameters are estimated by observing volatility scaling and correlation properties. We show that the Heston model with at least two time scales for the volatility mean reverting dynamics satisfactorily describes price fluctuations ranging from time scales larger than 20 minutes to 160 days. At time scales shorter than 20 minutes we observe autocorrelated returns and power law tails incompatible with the Heston model. Despite major regulatory changes, hyperinflation and currency crises experienced by the Brazilian market in the period studied, the general success of the description provided may be regarded as an evidence for a general underlying dynamics of price fluctuations at intermediate mesoeconomic time scales well approximated by the Heston model. We also notice that the connection between the Heston model and Ehrenfest urn models could be exploited for bringing new insights into the microeconomic market mechanics.Comment: 20 pages, 9 figures, to appear in Physica

Structure of Extreme Correlated Equilibria: a Zero-Sum Example and its Implications

We exhibit the rich structure of the set of correlated equilibria by analyzing the simplest of polynomial games: the mixed extension of matching pennies. We show that while the correlated equilibrium set is convex and compact, the structure of its extreme points can be quite complicated. In finite games the ratio of extreme correlated to extreme Nash equilibria can be greater than exponential in the size of the strategy spaces. In polynomial games there can exist extreme correlated equilibria which are not finitely supported; we construct a large family of examples using techniques from ergodic theory. We show that in general the set of correlated equilibrium distributions of a polynomial game cannot be described by conditions on finitely many moments (means, covariances, etc.), in marked contrast to the set of Nash equilibria which is always expressible in terms of finitely many moments

Megacities and High Speed Rail systems: which comes first?

A megacity is usually defined as a metropolitan area with a total population in excess of 10 million people. The number of megacities is increasing worldwide. In most agglomerations and megacities, urban planning and public infrastructure can guide the urban development in order to achieve a proper sustainable structure only partially. The extension of cities is in most cases in advance of urban development work and the provision of public facilities (Kotter, 2004). In Europe, apart from London and Paris, megacities are rarer. However, due to the general high density of population in Europe and the short distance between medium and large cities there is the possibility of High Speed Rail (HSR) enables the emergence of groups of cities that will be linked together and thus reap the economic benefits associated with megacities, namely economies of scale, economies of agglomeration and bigger labour markets. In this contribution the authors argue that in some cases, specific facilities can foster the formation of megacities; in fact, this is the case of HSR systems. Specifically, High-Speed trains can be used to solve two different accessibility problems. In the first case, where a point-to-point link is dominant, each train is a potential substitute for an air connection between two cities, i.e. it connects cities (or rather CBDs) at long distance with a direct train connection (Blum et al., 1997).The HSR links between Paris and Lyon, Paris and London and, Tokyo and Osaka, could be seen as examples of this first type of train connection. In the second case, where a HSR network is dominant, the rail system links together many cities and CBDs and, hence, creates a new type of region with a high intra-regional accessibility sharing a common labour market and a common market for household and business services. In this case the HSR binds together cities in a band, where each pair of cities is at a time distance of between 20 minutes and 1 hour, allowing daily commuting. In the U.S., HSR projects are very recent and they will have the role of connecting already formed megacities. An example is the state of California, which is planning an 800-mile HSR service connecting Los Angeles and San Francisco into a two and a half hour trip. On the other hand, Europe, together with Asia, is the leader in HSR systems; in fact the development of HSR has been one of the central features of recent European Union transport infrastructure policy. The proposals for a European HSR network emerged in a report of the 1990 Community of European Railways and this was essentially adopted as the base for what became the European Community’s proposed Trans-European Network for HSR (Vickerman, 1997). In this paper the case studies of Portugal, where the HSR is a work in progress and of Italy, in which some lines have already been built, will be described in detail from the viewpoint of the various kinds of development described above