64 resultados para Traffic Speed Change.


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This research project aimed the following goal: promote the creation, use and disclosure of OER in a Group of Schools, involving schools and teachers from different learning levels, expecting to test and validate the use of OER, in a learning-teaching model towards curricular innovation. Defining as a starting point different subjects and teachers from distinct academic areas, we have implemented a set of activities leading to the creation of OER supported, when possible, in FLOSS tools. We adopted an action research methodology with a dual purpose: to act within a community of teachers and students, while increasing at the same time their knowledge, as well as the researcher's. The activity was developed cooperatively in order to process a certain reality of the teaching-learning process, through practical/reflective action towards it and inducing its implementation by others in the Portuguese School System, based on the production and sharing OER.

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In standard multivariate statistical analysis common hypotheses of interest concern changes in mean vectors and subvectors. In compositional data analysis it is now well established that compositional change is most readily described in terms of the simplicial operation of perturbation and that subcompositions replace the marginal concept of subvectors. To motivate the statistical developments of this paper we present two challenging compositional problems from food production processes.Against this background the relevance of perturbations and subcompositions can beclearly seen. Moreover we can identify a number of hypotheses of interest involvingthe specification of particular perturbations or differences between perturbations and also hypotheses of subcompositional stability. We identify the two problems as being the counterpart of the analysis of paired comparison or split plot experiments and of separate sample comparative experiments in the jargon of standard multivariate analysis. We then develop appropriate estimation and testing procedures for a complete lattice of relevant compositional hypotheses

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In this paper, we consider the ATM networks in which the virtual path concept is implemented. The question of how to multiplex two or more diverse traffic classes while providing different quality of service requirements is a very complicated open problem. Two distinct options are available: integration and segregation. In an integration approach all the traffic from different connections are multiplexed onto one VP. This implies that the most restrictive QOS requirements must be applied to all services. Therefore, link utilization will be decreased because unnecessarily stringent QOS is provided to all connections. With the segregation approach the problem can be much simplified if different types of traffic are separated by assigning a VP with dedicated resources (buffers and links). Therefore, resources may not be efficiently utilized because no sharing of bandwidth can take place across the VP. The probability that the bandwidth required by the accepted connections exceeds the capacity of the link is evaluated with the probability of congestion (PC). Since the PC can be expressed as the CLP, we shall simply carry out bandwidth allocation using the PC. We first focus on the influence of some parameters (CLP, bit rate and burstiness) on the capacity required by a VP supporting a single traffic class using the new convolution approach. Numerical results are presented both to compare the required capacity and to observe which conditions under each approach are preferred

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The statistical analysis of literary style is the part of stylometry that compares measurable characteristicsin a text that are rarely controlled by the author, with those in other texts. When thegoal is to settle authorship questions, these characteristics should relate to the author’s style andnot to the genre, epoch or editor, and they should be such that their variation between authors islarger than the variation within comparable texts from the same author.For an overview of the literature on stylometry and some of the techniques involved, see for exampleMosteller and Wallace (1964, 82), Herdan (1964), Morton (1978), Holmes (1985), Oakes (1998) orLebart, Salem and Berry (1998).Tirant lo Blanc, a chivalry book, is the main work in catalan literature and it was hailed to be“the best book of its kind in the world” by Cervantes in Don Quixote. Considered by writterslike Vargas Llosa or Damaso Alonso to be the first modern novel in Europe, it has been translatedseveral times into Spanish, Italian and French, with modern English translations by Rosenthal(1996) and La Fontaine (1993). The main body of this book was written between 1460 and 1465,but it was not printed until 1490.There is an intense and long lasting debate around its authorship sprouting from its first edition,where its introduction states that the whole book is the work of Martorell (1413?-1468), while atthe end it is stated that the last one fourth of the book is by Galba (?-1490), after the death ofMartorell. Some of the authors that support the theory of single authorship are Riquer (1990),Chiner (1993) and Badia (1993), while some of those supporting the double authorship are Riquer(1947), Coromines (1956) and Ferrando (1995). For an overview of this debate, see Riquer (1990).Neither of the two candidate authors left any text comparable to the one under study, and thereforediscriminant analysis can not be used to help classify chapters by author. By using sample textsencompassing about ten percent of the book, and looking at word length and at the use of 44conjunctions, prepositions and articles, Ginebra and Cabos (1998) detect heterogeneities that mightindicate the existence of two authors. By analyzing the diversity of the vocabulary, Riba andGinebra (2000) estimates that stylistic boundary to be near chapter 383.Following the lead of the extensive literature, this paper looks into word length, the use of the mostfrequent words and into the use of vowels in each chapter of the book. Given that the featuresselected are categorical, that leads to three contingency tables of ordered rows and therefore tothree sequences of multinomial observations.Section 2 explores these sequences graphically, observing a clear shift in their distribution. Section 3describes the problem of the estimation of a suden change-point in those sequences, in the followingsections we propose various ways to estimate change-points in multinomial sequences; the methodin section 4 involves fitting models for polytomous data, the one in Section 5 fits gamma modelsonto the sequence of Chi-square distances between each row profiles and the average profile, theone in Section 6 fits models onto the sequence of values taken by the first component of thecorrespondence analysis as well as onto sequences of other summary measures like the averageword length. In Section 7 we fit models onto the marginal binomial sequences to identify thefeatures that distinguish the chapters before and after that boundary. Most methods rely heavilyon the use of generalized linear models

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The automatic interpretation of conventional traffic signs is very complex and time consuming. The paper concerns an automatic warning system for driving assistance. It does not interpret the standard traffic signs on the roadside; the proposal is to incorporate into the existing signs another type of traffic sign whose information will be more easily interpreted by a processor. The type of information to be added is profuse and therefore the most important object is the robustness of the system. The basic proposal of this new philosophy is that the co-pilot system for automatic warning and driving assistance can interpret with greater ease the information contained in the new sign, whilst the human driver only has to interpret the "classic" sign. One of the codings that has been tested with good results and which seems to us easy to implement is that which has a rectangular shape and 4 vertical bars of different colours. The size of these signs is equivalent to the size of the conventional signs (approximately 0.4 m2). The colour information from the sign can be easily interpreted by the proposed processor and the interpretation is much easier and quicker than the information shown by the pictographs of the classic signs

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Els programes formatius d’educació viària són una mesura penal alternativa que s’imposa habitualment als autors dels delictes relacionats amb el trànsit (articles 379 i següents del Codi Penal) per suspendre o substituir la pena de presó. Aquests programes tenen un doble objectiu: aconseguir reduir a curt termini la sinistralitat viària i propiciar un canvi cultural permanent en la conducció. L’objectiu principal d’aquesta recerca va ser identificar les característiques comunes dels infractors de trànsit que fan aquest tipus d’intervenció, conèixer els factors de risc associats a aquests infractors i en quina mesura l’estat psicològic és un factor de risc en l’estil de conducció. També es volia determinar si hi havia diferències entre les entitats que impartien la formació, avaluar l’efectivitat d’aquests programes en l’estil de conducció dels participants en finalitzar el curs i conèixer la reincidència dels seus participants i la seva relació amb l’estat i el canvi de les variables de l’estudi. La mostra va comptar amb 278 participants voluntaris del total de 354 infractors de trànsit que van realitzar un programa formatiu entre l’1 d’abril de 2009 i el 13 de febrer de 2010. D’aquests, un total de 100 participants van autoritzar a ser contactats novament entre el desembre del 2011 i el gener del 2012, per mirar la reincidència. Les fonts d’informació van ser els qüestionaris passats als infractors i el buidatge de la base de dades d’execució penal del Departament de Justícia, amb informació judicial i personal i el seguiment dels usuaris fins a dos anys després d’haver finalitzat el curs formatiu, per saber si havien tornat a reincidir en el mateix delicte.

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Los programas formativos de educación vial son una medida penal alternativa que se impone habitualmente a los autores de delitos relacionados con el tráfico (artículos 379 y siguientes del Código Penal) para suspender o sustituir la pena de prisión. Estos programas tienen un doble objetivo: conseguir reducir a corto plazo la siniestralidad vial y propiciar un cambio cultural permanente en la conducción. El objetivo principal de esta investigación fue identificar las características comunes de los infractores de tráfico que han de hacer este tipo de intervención y conocer sus factores de riesgo. También se estudiaron las diferencias entre las entidades que imparten los cursos formativos, se evaluó su efectividad y se estudió la reincidencia de los conductores. En total participaron 278 infractores que realizaron un programa formativo entre el 1 de abril de 2009 y el 13 de febrero de 2010 y se les siguió hasta enero de 2012.

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This paper analyses the effects that technological changes in agriculture would have on environmental, social and economic indicators. Specifically, our study is focused on two alternative technological improvements: the modernization of water transportation systems versus the increase in the total factor productivity of agriculture. Using a computable general equilibrium model for the Catalan economy, our results suggest that a water policy that leads to greater economic efficiency is not necessarily optimal if we consider social or environmental criteria. Moreover, improving environmental sustainability depends less on the type of technological change than on the institutional framework in which technological change occurs. Keywords: agricultural technological changes, computable general equilibrium model, economic impact, water policy

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El novembre de 2010, la Comissió Europea ha finalment donat a conèixer la seva "Energia 2020 Comunicació", un document estratègic en el marc més ampli del programa "Europa 2020". Una estratègia per al desenvolupament sostenible intel · ligent, i creixement inclusiu posa les bases d'un nou enfocament a la política d'energia a la UE. En el marc d'Europa 2020, la Iniciativa d'Energia recopila els resultats que ja s'han obtingut a través de la Estratègia de Lisboa 2000-2010, s'identifiquen les deficiències del passat i i introdueix nous objectius ambiciosos per a la UE en matèria de política energètica.

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The application of Discriminant function analysis (DFA) is not a new idea in the studyof tephrochrology. In this paper, DFA is applied to compositional datasets of twodifferent types of tephras from Mountain Ruapehu in New Zealand and MountainRainier in USA. The canonical variables from the analysis are further investigated witha statistical methodology of change-point problems in order to gain a betterunderstanding of the change in compositional pattern over time. Finally, a special caseof segmented regression has been proposed to model both the time of change and thechange in pattern. This model can be used to estimate the age for the unknown tephrasusing Bayesian statistical calibration

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Throughout the past decade, social media have come on the scene of various popular revolts. Their role as tools of information and coordination of social movements, from the Iranian Green Movement in 2009 to the Arab uprisings in 2011, has been widely debated. In most cases, online activism through blogs, Facebook, Twitter or other forms of social media has allowed citizens to be part of a social networking exercise and to engage in a public sphere that would have otherwise been unreachable to them due to severe repression. In Tunisia and Egypt, social media helped protests start and expand thanks to their ability to coordinate and disseminate information quickly. The new information and communication tools were an influential factor in accelerating the revolutionary processes across the Arab world, albeit they cannot be seen as neither the spur nor the drivers of any revolution.

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We derive analytical expressions for the propagation speed of downward combustion fronts of thin solid fuels with a background flow initially at rest. The classical combustion model for thin solid fuels that consists of five coupled reaction-convection-diffusion equations is here reduced into a single equation with the gas temperature as the single variable. For doing so we apply a two-zone combustion model that divides the system into a preheating region and a pyrolyzing region. The speed of the combustion front is obtained after matching the temperature and its derivative at the location that separates both regions.We also derive a simplified version of this analytical expression expected to be valid for a wide range of cases. Flame front velocities predicted by our analyticalexpressions agree well with experimental data found in the literature for a large variety of cases and substantially improve the results obtained from a previous well-known analytical expression

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The effect of initial conditions on the speed of propagating fronts in reaction-diffusion equations is examined in the framework of the Hamilton-Jacobi theory. We study the transition between quenched and nonquenched fronts both analytically and numerically for parabolic and hyperbolic reaction diffusion. Nonhomogeneous media are also analyzed and the effect of algebraic initial conditions is also discussed