81 resultados para urban traffic


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Treball de recerca realitzat per un grup d’alumnes d’ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l’any 2008. Es presenta un pla d’empresa del sector turístic. L’activitat de l’empresa serà organitzar viatges amb rutes organitzades per diferents capitals europees i també algunes rutes dintre del territori espanyol amb bicicleta, oferint un servei complet.

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Traffic forecasts provide essential input for the appraisal of transport investment projects. However, according to recent empirical evidence, long-term predictions are subject to high levels of uncertainty. This paper quantifies uncertainty in traffic forecasts for the tolled motorway network in Spain. Uncertainty is quantified in the form of a confidence interval for the traffic forecast that includes both model uncertainty and input uncertainty. We apply a stochastic simulation process based on bootstrapping techniques. Furthermore, the paper proposes a new methodology to account for capacity constraints in long-term traffic forecasts. Specifically, we suggest a dynamic model in which the speed of adjustment is related to the ratio between the actual traffic flow and the maximum capacity of the motorway. This methodology is applied to a specific public policy that consists of suppressing the toll on a certain motorway section before the concession expires.

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The battle between cities with regard to their creative possibilities has evolved into a process of multiplying ever-new images and variegated stories of urban attractiveness and success. Engineering “cool” images and “hot” stories about one’s city is now a central endeavor in the narratives of urban policy-making that center more and more on the idea of the entrepreneurial city. The making of an entrepreneurial image is enacted through various narrative genres that lie somewhere between place making and place marketing, between branding and boosting, between restoration and revanchism, between iconic architecture and mega-spectacle. This “imagineering” is not only part of the way cities try to (re)present themselves as entrepreneurial to various audiences through a real “image inflation” (Zukin, 2008, p. xii) but is 1 Forthcoming in: B. Lange,.A. Kalandides, B. Stoeber, I. Wellmann (Hrsg.) (2009): Governance der Kreativwirtschaft. Diagnosen und Handlungsoptionen. Transcript-Verlag, Bielefeld. 2 also inscribed in the various ways urban creativity and entrepreneurship can be studied, researched and imagined. In this chapter we aim to differentiate the political narratives of the entrepreneurial city as we emphasize the need to understand the politics of narration and make a plea for critical reflexivity in our forms of researching and theorizing. We will thus try to investigate how the politics of narration is intertwined with the narration of political concepts and will argue that the narrating of urban entrepreneurship can raise very different images and discourses of city life beyond those that are currently engineered. We will distinguish between a grand narrative, a counter-narrative, and an assemblage of more ambivalent little narratives, which we call prosaic narration. While the distinction between these three types might be seen as a bit too simple and “straight”, we believe that by juxtaposing these different forms of narration and alternating between them, we can help problematize the engineering of the city as entrepreneurial and imagine alternative views both of city life and of what is understood as its creativity.

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Suburbanization is changing the urban spatial structure and less monocentric metropolitan regions are becoming the new urban reality. Focused only on centers, most works have studied these spatial changes neglecting the role of transport infrastructure and its related location model, the “accessibility city”, in which employment and population concentrate in low-density settlements and close to transport infrastructure. For the case of Barcelona, we consider this location model and study the population spatial structure between 1991 and 2006. The results reveal a mix between polycentricity and the accessibility city, with movements away from the main centers, but close to the transport infrastructure.

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The problem of waste management is causing growing concern due to increasing generation rates, the emissions into soil, water and air, the social conflicts derived from the election of disposal sites and the loss of resources and energy among others. In this work, an innovative methodology is used to enable a better understanding of the waste generation and management system in Italy. Two new waste indicators are built to complement the conventional indicators used by official statistics. Then a multi-scale analysis of the Density of Waste Disposed (DWD) is carried out to highlight the territorial diversity of waste performances and test its contribution to detect plausible risky areas. Starting from Italian regions, the scale down goes on to the provincial level and, only for the region of Campania, the municipal one. First, the analysis shows that the DWD is able to complement the information provided by the conventional waste indicators. Second, the analysis shows the limitations of using a unique institutional solution to waste management problems. In this sense the multi-scale analysis provides with a more realistic picture of Italian waste system than using a single scale.

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Amb aquest projecte es vol donar una visó global dels sistemes d'informació geogràfica (SIG), cada vegada més implantats a qualsevol àrea de la nostra societat (urbanisme, climatologia, medi ambient, hidrologia, vies de comunicació, cadastre, etc.). De fet, "qualsevol cosa" (riu, canal, camí, pont, contenidor, cotxe, tren, casa, fanal, senyal de trànsit, oficina, avió, vaixell, etc.) que hi ha a terra (a sota o a sobre) és candidata a ser georeferenciada.

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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 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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L’objectiu principal del treball és analitzar les polítiques i plans turístics irlandesos nacionals, regionals i locals, i determinar com aquestos influeixen en el turisme urbà a Dublín. L’objectiu secundari és investigar el concepte de turisme urbà i examinar les tendències turístiques actuals i la seva repercussió en la formulació de polítiques

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This research explores critical environmental concepts from the standpoint of political ecology. It contrasts the Ecuadorian Kichua indigenous concept of Sumak Kawsay (i.e., living well), with discourses about natural, urban and rural areas. Sumak Kawsay was included in Ecuador’s 2008 constitution as an alternative to the neoclassical idea of development. This work reveals interesting insights from a variety of social and political viewpoints from both rural and urban areas. The research is based on the medium sized city of Cuenca, which is located in the southern Ecuadorian Andes. We used an adaptation of the Q Method to investigate stakeholders’ perceptions. Four remarkably well-defined viewpoints were revealed. Although these views contrast strongly with Sumak Kawsay, it is possible to transform this paradigm in the foundation of Cuenca’s public policies and institutional structure.

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One of the criticisms leveled at the model of dispersed city found all over the world is its unarticulated, random, and undifferentiated nature. To check this idea in the Barcelona Metropolitan Region, we estimated the impact of the urban spatial structure (CBD, subcenters and transportation infrastructures) over the population density and commuting distance. The results are unfavorable to the hypothesis of the increasing destructuring of cities given that the explanatory capacity of both functions improves over time, both when other control variables are not included and when they are included.

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L’informe que es presenta en aquest llibre és el resultat d’un nou acord de col·laboració entre el Programa de les Nacions Unides per als Assentaments Humans (ONU-Habitat) i l’Institut de Seguretat Pública de Catalunya, impulsat amb l’objectiu de millorar la seguretat en esdeveniments públics en els espais urbans a l’Àfrica. La fase pilot es va dur a terme el 2010, durant els dos seminaris de formació realitzats a Mollet del Vallès (Barcelona) com a part de la Plataforma Policia per al Desenvolupament Urbà (PPUD). En aquest informe es descriuen els orígens i l’estat de la iniciativa i resumeix els resultats. També s’inclouen algunes recomanacions per a millorar la seguretat d’esdeveniments públics. Font d'informació: http://www.onuhabitat.org.

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Several airline consolidation events have recently been completed both in Europe and in the United States. The model we develop considers two airlines operating hub-and-spoke networks, using different hubs to connect the same spoke airports. We assume the airlines to be vertically differentiated, which allows us to distinguish between primary and secondary hubs. We conclude that this differentiation in air services becomes more accentuated after consolidation, with an increased number of flights being channeled through the primary hub. However, congestion can act as a brake on the concentration of flight frequency in the primary hub following consolidation. Our empirical application involves an analysis of Delta s network following its merger with Northwest. We find evidence consistent with an increase in the importance of Delta s primary hubs at the expense of its secondary airports. We also find some evidence suggesting that the carrier chooses to divert traffic away from those hub airports that were more prone to delays prior to the merger, in particular New York s JFK airport. Keywords: primary hub; secondary hub; airport congestion; airline consolidation; airline networks JEL Classi fication Numbers: D43; L13; L40; L93; R4

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This paper analyses the likelihood of leaving and joining employment in an urban area. Estimates show that individual, firm, regulatory and macroeconomic factors a ffect urban (un)employment duration in di fferent degrees. Also, national and urban (un)employment seem to share a common baseline hazard and similar macroeconomic and regulatory drivers. Individual characteristics are the only source of di fference we can identify between national and urban (un)employment duration. Keywords: Duration Models, Urban (Un)employment. JEL Classi fication: J64, R23.