421 resultados para Simulació
Resumo:
L'interès per les carreres relacionades amb les enginyeries del camp de les Tecnologies de la Informació i la Comunicació (TIC) va caient any rere any i això es tradueix en menys matriculacions per cada any que passa. Una de les causes principals és la falta de motivació i interès envers aquestes carreres. Aquest problema s’atribueix a que les metodologies d’aprenentatge tradicionals no s’adeqüen a les necessitats i requeriments dels estudiants d’avui dia, que han crescut envoltats de tecnologia, i se’ls coneix amb el nom en anglès de digitalnatives.L’aprenentatge basat en jocs sorgeix com a una possible solució per afrontar aquesta falta d’interès per les àrees del coneixement relacionades amb les enginyeries TIC. Aquest mètode d'aprenentatge consisteix en que els estudiants aprenguin conceptes de les TIC mentre estan jugant a un joc. Per tant, en el context d’aquest PFC, ens centrarem en el disseny i implementació d’un joc per aprendre conceptes bàsics de les enginyeries TIC. En concret, el disseny d’aquest joc segueix les característiques definides per un model conceptual que descriuquins són els elements necessaris per crear jocs basats en puzles: quins són els elements principals que componen aquests tipus de joc i quines pistes es poden afegir per guiar a l’estudiant en el procés d’aprenentatge amb el joc. Per altra banda, pel que fa a laimplementació del joc, s’utilitzarà tecnologia basada en interfícies tangibles.Per tal d’analitzar el joc basat en puzles que s’ha dissenyat i implementat per aprendre conceptes basics de les Enginyeries TIC, s’ha portat a terme una avaluació amb estudiants d’un centre educatiu. Aspectes com el disseny de pistes, l’experiència dels estudiants amb el joc il’aprenentatge amb el joc seran analitzats per extreure les conclusions oportunes.
Resumo:
Actualment existeix una falta d'interès per part dels estudiants a l'àrea de les enginyeries en Tecnologies de la Informació i la Comunicació (TIC) que es pot veure reflectida en el descens de les matriculacions universitàries en aquest àmbit. Aquest fet està relacionat amb que la nova generació d‟estudiants està constantment en contacte amb tota mena d'aparells tecnològics estimulants i a l‟hora de l‟estudi poden sofrir una falta d‟interès per l‟ús d‟una metodologia d'aprenentatge més tradicional. En aquest sentit s'ha investigat que l‟ús de jocs com a eina educativa pot ser una bona solució per afrontar aquesta falta d'interès. No obstant això, actualment no existeixen gaires jocs destinats a aprendre conceptes relacionats amb les enginyeries TIC i que proporcionin als estudiants els mecanismes d'ajuda necessaris per donar-los suport durant l'aprenentatge d‟aquests nous conceptes. En aquest projecte es desenvoluparà un joc educatiu per a estudiants amb l‟objectiu de proporcionar uns primers coneixements sobre les TIC. Per una banda, per al disseny del joc s‟utilitzarà un model conceptual que defineix els elements necessaris per a dissenyar jocs basats en resoldre puzles. A més, aquest model conceptual permet el disseny no només de jocs per a PCs, sinó també de jocs tangibles i exploratius (mitjançant tecnologia mòbil). En el nostre cas, ens centrarem en la implementació d‟un joc tangible. Per altra banda, pel que fa a la implementació, tindrem en compte l‟estàndard educatiu d‟IMS Learning Design, demostrant d‟aquesta manera que aquest tipus de jocs es poden beneficiar dels avantatges que aporten els estàndards educatius. Per tant, en aquest PFC es dissenyarà i implementarà un joc tangible basat en puzles dintre de l‟àrea d‟arquitectura d‟ordinadors. El joc constarà de tres mini-jocs que es presentaran com jocs de realitat augmentada amb el suport d‟un ordinador i unes peces físiques amb les que interactuaran els usuaris. El sistema proporcionarà un sistema d‟ajuda i un sistema de puntuació. Per últim, avaluarem el joc en un centre escolar amb estudiants de 4t d‟ESO amb la finalitat d'analitzar les valoracions dels estudiants respecte el joc i les pistes proporcionades.
Resumo:
A 15 year old girl who had pain, oedema of her left hand, and fever of four months' duration is described. Marked demineralisation of her hand was shown by radiography, and increased articular uptake by technetium-99m bone scan. All these changes were indistinguishable from reflex sympathetic dystrophy. After two admissions to hospital and multiple explorations we discovered that she had induced her symptoms herself and a diagnosis of Munchausen's syndrome was made. As far as we know this presentation has not been previously reported and might help to explain the physiopathology of some signs of reflex sympathetic dystrophy.
Resumo:
In this paper we try to analyze the role of fiscal policy in fostering a higher participation of the different production factors in the human capital production sector in the long-run. Introducing a tax on physical capital and differentiating both a tax on raw labor wage and a tax on skills or human capital we also attempt to present a way to influence inequality as measured by the skill premium, thus trying to relate the increase in human capital with the decrease in income inequality. We will do that in the context of a non-scale growth model.The model here is capable to alter the shares of private factors devoted to each of the two production sectors, final output and human capital, and affect inequality in a different way according to the different tax changes. The simulation results derived in the paper show how a human capital (skills) tax cut, which could be interpreted as a reduction in progressivity, ends up increasing both the shares of labor and physical capital devoted to the production of knowledge and decreasing inequality. Moreover, a raw labor wage tax decrease, which could also be interpreted as an increase in the progressivity of the system, increases the share of labor devoted to the production of final output and increases inequality. Finally, a physical capital tax decrease reduces the share of physical capital devoted to the production of knowledge and allows for a lower inequality value. Nevertheless, none of the various types of taxes ends up changing the share of human capital in the knowledge production, which will deserve our future attention
Resumo:
This paper proposes a test statistic for the null hypothesis of panel stationarity that allows for the presence of multiple structural breaks. Two different speci¿cations are considered depending on the structural breaks affecting the individual effects and/or the time trend. The model is ¿exible enough to allow the number of breaks and their position to differ across individuals. The test is shown to have an exact limit distribution with a good ¿nite sample performance. Its application to a typical panel data set of real per capita GDP gives support to the trend stationarity of these series
Resumo:
In this paper we examine the effect of tax policy on the relationship between inequality and growth in a two-sector non-scale model. With non-scale models, the longrun equilibrium growth rate is determined by technological parameters and it is independent of macroeconomic policy instruments. However, this fact does not imply that fiscal policy is unimportant for long-run economic performance. It indeed has important effects on the different levels of key economic variables such as per capita stock of capital and output. Hence, although the economy grows at the same rate across steady states, the bases for economic growth may be different.The model has three essential features. First, we explicitly model skill accumulation, second, we introduce government finance into the production function, and we introduce an income tax to mirror the fiscal events of the 1980¿s and 1990¿s in the US. The fact that the non-scale model is associated with higher order dynamics enables it to replicate the distinctly non-linear nature of inequality in the US with relative ease. The results derived in this paper attract attention to the fact that the non-scale growth model does not only fit the US data well for the long-run (Jones, 1995b) but also that it possesses unique abilities in explaining short term fluctuations of the economy. It is shown that during transition the response of the relative simulated wage to changes in the tax code is rather non-monotonic, quite in accordance to the US inequality pattern in the 1980¿s and early 1990¿s.More specifically, we have analyzed in detail the dynamics following the simulation of an isolated tax decrease and an isolated tax increase. So, after a tax decrease the skill premium follows a lower trajectory than the one it would follow without a tax decrease. Hence we are able to reduce inequality for several periods after the fiscal shock. On the contrary, following a tax increase, the evolution of the skill premium remains above the trajectory carried on by the skill premium under a situation with no tax increase. Consequently, a tax increase would imply a higher level of inequality in the economy
Resumo:
In this paper we try to analyze the role of fiscal policy in fostering a higher participation of the different production factors in the human capital production sector in the long-run. Introducing a tax on physical capital and differentiating both a tax on raw labor wage and a tax on skills or human capital we also attempt to present a way to influence inequality as measured by the skill premium, thus trying to relate the increase in human capital with the decrease in income inequality. We will do that in the context of a non-scale growth model.The model here is capable to alter the shares of private factors devoted to each of the two production sectors, final output and human capital, and affect inequality in a different way according to the different tax changes. The simulation results derived in the paper show how a human capital (skills) tax cut, which could be interpreted as a reduction in progressivity, ends up increasing both the shares of labor and physical capital devoted to the production of knowledge and decreasing inequality. Moreover, a raw labor wage tax decrease, which could also be interpreted as an increase in the progressivity of the system, increases the share of labor devoted to the production of final output and increases inequality. Finally, a physical capital tax decrease reduces the share of physical capital devoted to the production of knowledge and allows for a lower inequality value. Nevertheless, none of the various types of taxes ends up changing the share of human capital in the knowledge production, which will deserve our future attention
Resumo:
[cat] En el context dels mercats a dues bandes, considerem, en primer lloc, que els jugadors poden escollir on dur a terme les seves transaccions. Mostrem que el joc corresponent a aquesta situació, que es representa pel màxim d’un conjunt finit de jocs d’assignació, pot ser un joc no equilibrat. Aleshores proporcionem condicions per a l’equilibri del joc i, per aquest cas, analitzem algunes propietats del core del joc. En segon lloc, considerem que els jugadors poden fer transaccions en diversos mercats simultàniament i, llavors, sumar els guanys obtinguts. El joc corresponent, representat per la suma d’un conjunt finit de jocs d’assignació, és equilibrat. A més a més, sota certes condicions, la suma dels cores dels dos jocs d’assignació coincideix amb el core del joc suma.
Resumo:
This paper proposes a test statistic for the null hypothesis of panel stationarity that allows for the presence of multiple structural breaks. Two different speci¿cations are considered depending on the structural breaks affecting the individual effects and/or the time trend. The model is ¿exible enough to allow the number of breaks and their position to differ across individuals. The test is shown to have an exact limit distribution with a good ¿nite sample performance. Its application to a typical panel data set of real per capita GDP gives support to the trend stationarity of these series
Resumo:
In this paper we examine the effect of tax policy on the relationship between inequality and growth in a two-sector non-scale model. With non-scale models, the longrun equilibrium growth rate is determined by technological parameters and it is independent of macroeconomic policy instruments. However, this fact does not imply that fiscal policy is unimportant for long-run economic performance. It indeed has important effects on the different levels of key economic variables such as per capita stock of capital and output. Hence, although the economy grows at the same rate across steady states, the bases for economic growth may be different.The model has three essential features. First, we explicitly model skill accumulation, second, we introduce government finance into the production function, and we introduce an income tax to mirror the fiscal events of the 1980¿s and 1990¿s in the US. The fact that the non-scale model is associated with higher order dynamics enables it to replicate the distinctly non-linear nature of inequality in the US with relative ease. The results derived in this paper attract attention to the fact that the non-scale growth model does not only fit the US data well for the long-run (Jones, 1995b) but also that it possesses unique abilities in explaining short term fluctuations of the economy. It is shown that during transition the response of the relative simulated wage to changes in the tax code is rather non-monotonic, quite in accordance to the US inequality pattern in the 1980¿s and early 1990¿s.More specifically, we have analyzed in detail the dynamics following the simulation of an isolated tax decrease and an isolated tax increase. So, after a tax decrease the skill premium follows a lower trajectory than the one it would follow without a tax decrease. Hence we are able to reduce inequality for several periods after the fiscal shock. On the contrary, following a tax increase, the evolution of the skill premium remains above the trajectory carried on by the skill premium under a situation with no tax increase. Consequently, a tax increase would imply a higher level of inequality in the economy
Resumo:
In this paper we describe the results of a simulation study performed to elucidate the robustness of the Lindstrom and Bates (1990) approximation method under non-normality of the residuals, under different situations. Concerning the fixed effects, the observed coverage probabilities and the true bias and mean square error values, show that some aspects of this inferential approach are not completely reliable. When the true distribution of the residuals is asymmetrical, the true coverage is markedly lower than the nominal one. The best results are obtained for the skew normal distribution, and not for the normal distribution. On the other hand, the results are partially reversed concerning the random effects. Soybean genotypes data are used to illustrate the methods and to motivate the simulation scenarios
Resumo:
In this paper we analyse, using Monte Carlo simulation, the possible consequences of incorrect assumptions on the true structure of the random effects covariance matrix and the true correlation pattern of residuals, over the performance of an estimation method for nonlinear mixed models. The procedure under study is the well known linearization method due to Lindstrom and Bates (1990), implemented in the nlme library of S-Plus and R. Its performance is studied in terms of bias, mean square error (MSE), and true coverage of the associated asymptotic confidence intervals. Ignoring other criteria like the convenience of avoiding over parameterised models, it seems worst to erroneously assume some structure than do not assume any structure when this would be adequate.
Resumo:
Spanning avalanches in the 3D Gaussian Random Field Ising Model (3D-GRFIM) with metastable dynamics at T=0 have been studied. Statistical analysis of the field values for which avalanches occur has enabled a Finite-Size Scaling (FSS) study of the avalanche density to be performed. Furthermore, a direct measurement of the geometrical properties of the avalanches has confirmed an earlier hypothesis that several types of spanning avalanches with two different fractal dimensions coexist at the critical point. We finally compare the phase diagram of the 3D-GRFIM with metastable dynamics with the same model in equilibrium at T=0.
Resumo:
An analytical model of an amorphous silicon p-i-n solar cell is presented to describe its photovoltaic behavior under short-circuit conditions. It has been developed from the analysis of numerical simulation results. These results reproduce the experimental illumination dependence of short-circuit resistance, which is the reciprocal slope of the I(V) curve at the short-circuit point. The recombination rate profiles show that recombination in the regions of charged defects near the p-i and i-n interfaces should not be overlooked. Based on the interpretation of the numerical solutions, we deduce analytical expressions for the recombination current and short-circuit resistance. These expressions are given as a function of an effective ¿¿ product, which depends on the intensity of illumination. We also study the effect of surface recombination with simple expressions that describe its influence on current loss and short-circuit resistance.