European cities of today are under the challenge to find ways to stay competitive and flourish in a rapidly changing world, where the old patterns of centrality and periphery not necessarily holds true. New and improved communication networks, a changed political geography in Europe, and the globalisation of not only the financial and industrial markets but also to a certain extent the globalisation of people, have all led to great challenges for cities and regions. In a changed spatial reality the classic monocentric models are challenged by newer models of urbanisation. The polycentric urban region is one such model which has been used to describe urban regions like the Randstad in the Netherlands and the Rhein-Ruhr region in Germany. Regions which lack the single dominant central city of the monocentric models of old, and instead shows a high degree of more equal-sized and sometimes more specialised cities in regional cooperation. The polycentric urban region is in that aspect a possible model for how other urbanised regions in Europe may act to be able to position themselves as attractive urban regions and regional hubs in the European urban network. Polycentric urban regions are not a universal solution, though. For such regions to work there are a number of prerequisites to be filled, something that makes it a possible future for regions like Haute-Normandie in France, where the two cities of Le Havre and Rouen have the possibility to form one urban region and already show signs of heading in that direction, while a region like Dolnośląskie in Poland – where the city of Wrocław is the dominant city in what makes for a more classic monocentric region – has much less opportunity to use a polycentric strategy on the regional level to become competitive. On the other hand such a city and region can instead benefit from the fact that Poland is to a high degree a polycentric nation, and as one of the larger cities in such an environment, Wrocław has the opportunity to position itself as a hub in the European urban network in a way that Le Havre and Rouen cannot, due to their physical location close to the giant European urban region of Paris. / Dagens europeiska städer står inför en utmaning att finna sätt att förbli konkurrenskraftiga och framgångsrika i en snabbt föränderlig värld, där de gamla mönstren vad gäller centralitet och periferi inte längre nödvändigtvis gäller. Nya och förbättrade kommunikationsnätverk, en förändrad politisk geografi i Europa, globaliseringen av inte bara de finansiella och industriella systemen, utan även till viss del en globalisering av människorna, har alla lett till stora utmaningar för städer och regioner. I en förändrad rumsgeografisk verklighet utmanas de klassiska monocentriska modellerna av nyare urbaniseringsmodeller. Den polycentriska urbana regionen är en sådan modell som har använts för att beskriva urbana regioner som Randstad i Nederländerna och Rhein-Ruhrregionen i Tyskland. Regioner som saknar den ensamt dominierande centrala staden från de klassiska monocentriska modellerna, och istället uppvisar en hög grad av mer jämnstora och ibland mer specialiserade städer i regionalt samarbete. Den polycentriska urbana regionen är mot den bakgrunden en möjlig modell för hur andra urbaniserade regioner i Europa kan agera för att positionera sig själva som attraktiva urbana regioner och regionala nav i det Europeiska urbana nätverket. Polycentriska urbana regioner är däremot inte någon universallösning. För att sådana regioner ska fungera krävs att ett antal punkter är uppfyllda, något som gör det till en möjlig framtid för regioner som exempelvis Haute-Normandie i Frankrike, där de två städerna Le Havre och Rouen tillsammans kan bilda en urban region och redan visar tecken på att gå i den riktningen, medan en region som Dolnośląskie i Polen – där staden Wrocław är den dominerande staden i vad som utgör en mer traditionell monocentrisk region – har betydligt mindre möjlighet att använda sig av en polycentrisk strategi på det regionala planet för att bli konkurrenskraftig. Å andra sidan kan en sådan stad och region istället utnyttja det faktum att Polen är en ovanligt polycentrisk stat, och som en av de större städerna i en sådan miljö har Wrocław möjligheten att positionera sig själv som ett nav i det europeiska urbana nätverket på ett sätt som Le Havre och Rouen inte kan, till följd av deras fysiska lokalisering nära den gigantiska europeiska urbaniserade regionen Paris.

Este trabalho propõe estratégias de roteamento e de controle de acesso ao meio destinadas as redes urbanas, motivadas pelo monitoramento e controle de variáveis elétricas relacionadas à iluminação pública. Tais estratégias foram desenvolvidas segundo requisitos da aplicação, trabalhos encontrados na literatura, limitações do protocolo IEEE 802.15.4 e as especificações RFC 5548 e IEEE 802.15.4e (draft). As estratégias desenvolvidas foram incorporadas a protocolos encontrados na literatura, as quais geraram protocolos aperfeiçoados para redes urbanas, dentre eles GGPSR e gradiente em função da maior distância, utilizados para o tráfego divergente e convergente, respectivamente. O protocolo GGPSR é composto pelo algoritmo geográfico GPSR, geocast e retransmissões para os vizinhos seguindo o critério do GGPSR em caso de falha. O protocolo baseado na maior distância é composto pelo algoritmo do gradiente, o qual utiliza a maior distância no caso de receptores com pesos de gradiente iguais e retransmissões seguindo o mesmo critério. Foi utilizado um modelo de propagação realista, no qual foi aplicada a estratégia de mapeamento de vizinhos dos nós de acordo com a distância aproximada fornecida pelo atributo do pacote RSSI. Além disso, para ambos os tipos de tráfego, foi aplicado o mecanismo de controle de acesso ao meio RIT com o objetivo de minimizar o consumo energético. A avaliação dos protocolos gerados a partir dessas estratégias foi feita em simulação utilizando a ferramenta NS-2 integrada em cenários de grande escala fornecidos pela concessionária de iluminação pública Elektro, segundo os critérios de energia remascente da rede, média de atraso fim a fim e taxa de entrega fim a fim. Os resultados obtidos mostram que os protocolos gerados superam protocolos propostos na literatura; além disso, a estratégia baseada na distância obtida pelo atributo RSSI viabiliza a aplicação do protocolo GGPSR. Em relação à aplicação do RIT com a estratégia de parâmetros em função do gradiente, esta se mostrou mais eficiente em comparação com os parâmetros de RIT iguais para todos os nós. / This work proposes routing and medium access control strategies for urban networks, particularly related to monitoring and control of electric variables in the street lighting system. Such strategies were developed according to application requirements, studies in the literature, limitations of the IEEE 802.15.4 protocol, and RFC 5548 and IEEE 802.15.4e (draft) specifications. Strategies were incorporated into protocols found in the literature, which generated specific improved protocols for urban networks, including GGPSR and Gradient based on the farthest neighbor, applied to divergent and convergent traffic, respectively. The GGPSR protocol is composed by the GPSR algorithm, geocast and retransmissions to neighbors according to the GGPSR criterion when a failure occurs. The protocol based on the longest distance comprises the gradient algorithm, which considers the longest distance when receivers have equal gradient weights and retransmissions follow the same criterion. A realistic propagation model was used, implementing the strategy to map neighboring nodes according to the approximate distance provided by the RSSI packet attribute. Moreover, for both traffic ypes, the RIT medium access control mechanism was used in order to minimize energy consumption. Protocols generated by these strategies were evaluated through simulation in NS-2 tool applied to large scale scenarios provided by public street lighting concessionaire Elektro, according to the criteria of remaining energy network, end-to-end average delay and end-to-end delivery rate. Results show that the generated protocols outperform protocols proposed in the literature; in addition, the strategy based on the distance obtained by the RSSI attribute enables the use of the GGPSR protocol. Regarding the use of RIT considering the parameters as a function of the gradient, this strategy is more efficient compared to using the same RIT parameters for all nodes.

Esta pesquisa disserta sobre o processo de convergência entre o espaço urbano e as mídias locativas, que forma um terceiro espaço: o espaço cíbrido. O termo cíbrido foi criado pelo arquiteto Peter Anders, para designar um meio híbrido onde se desenvolvem as práticas sociais relacionadas à cibercultura. Com a difusão da Internet 1.0 na década de 90, que ocorre a partir da venda massiva de computadores pessoais, as mais variadas vertentes do conhecimento se debruçaram sobre as implicações do surgimento de um novo lugar: o espaço virtual. Porém é especialmente entre os \'artistas digitais\' da Net.art e arquitetos que se investigou as formas de perceber, produzir e criar esteticamente este novo lugar. Uma década mais tarde, o meio virtual sofreu uma nova guinada: a difusão dos dispositivos portáteis de telecomunicação: os smartphones, acoplados com dispositivos de rastreamento, demarcação e mapeamento espacial. As práticas resultantes destas novas mídias: as mídias locativas, associam camadas informacionais aos objetos, às pessoas e aos agenciamentos em rede e localizam esta rede espacialmente. Para investigar o processo de hibridização entre a esfera informacional e o espaço, traçou-se um mapeamento de obras de arte e arquitetura que tratam especificamente deste tema. A seleção desses dois campos de conhecimento para a análise, se justifica por serem áreas correlatas que vêm promovendo mudanças paradigmáticas neste campo e trazendo contribuições essenciais para a compreensão das práticas sociais que envolvem os espaços cíbridos. Cada projeto selecionado oferece em sua especificidade, o suporte teórico, descritivo, sobre as atuais formas de convergência telemática no espaço e tensionam questões específicas desse processo de hibridização, contribuindo para o avanço do conhecimento acerca do processo de produção, apropriação e compartilhamento destas tecnologias com o espaço urbano. / This research talks about the issue and process of convergence between urban space and locative media, which form a third space: the Cybrid space. The Cybrid is a term coined by the architect Peter Anders, to designate a hybrid environment where to develop social practices related to cyberculture. With the spread of Internet 1.0 in the 90\'s, which takes place from the massive sales of personal computers, the aspects of knowledge have addressed the implications of the emergence of a new place: the virtual space. But it is especially among \'digital artists\' of Net.art and architects who investigated the ways of perceiving, producing and aesthetically create this new place. A decade later, the virtual environment has suffered a new twist: the distribution of portable telecommunication devices: smartphones, coupled with tracking devices, demarcation and spatial mapping. The resulting practices of these new media: locative media, associated informational layers to objects, people and assemblages networking and spatially locate this network. To investigate the process of hybridization between the informational sphere and space, drew up a mapping of art and architecture works that specifically address this issue. The selection of these two fields of knowledge for the analysis is justified because they are related areas that are promoting paradigmatic changes in this field and bringing essential contributions to the understanding of social practices involving cybrids spaces. Each project offers, the theoretical, descriptive support, on current forms of telematics convergence in space and tense specific issues that the hybridization process, contributing to the advancement of knowledge about the production process, ownership and sharing of these technologies urban space.

Made available in DSpace on 2016-06-02T19:53:32Z (GMT). No. of bitstreams: 1 MARTINEZ_Jonathan_2014.pdf: 11989383 bytes, checksum: 96fb53d9544014ea55b1e53ee779c134 (MD5) Previous issue date: 2014-03-14 / Financiadora de Estudos e Projetos / This study presents a pump scheduling problem for the capture, transfer and storage of water supply systems in urban networks, whose objective is to minimize the electricity cost associated to the pumping operations. To deal with the dynamic and random nature of the water-demand, we propose two-stage stochastic programming with recourse models, where the random variables are represented by a finite and discrete set of realizations or scenarios. The developed mathematical models are extensions of previous deterministic models of the literature and they reflect the basic assumption that a fixed cost could be incurred by the turn on/ turn off activities of the hydraulic pumps. In order to control violations of the water-demand constraints in the presence of multiple different scenarios, we also consider a robustness technique in an attempt to obtain almost feasible solutions. Last, but not least, we adopt a risk-aversion criteria so-called mean absolute deviation to obtain second-stage costs less dependent on the realizations of the scenarios. The scenarios were generated according to a Monte-Carlo simulation procedure that may use any probability distributions to produce the empirical probabilities of the random variables. As the proposed pump scheduling problem with fixed cost is a two-stage stochastic mixed 0 − 1 program, we develop a efficient hybrid heuristic to obtain good-quality solutions of practical instances in a plausible running time. Overall results evidence the stability of the scenario generation method, the sensitivity of the solution according to the key parameters of the mathematical model, and the efficiency of the heuristic in solving large instances. Finally, we show that is possible to save resources by solving the stochastic programming model instead of adopting simpler approaches based on the expected value. / Esse estudo apresenta um problema de programação de bombas para a captação, armazenamento e transferência de água em sistemas de abastecimentos de água em redes urbanas, cujo objetivo é minimizar o custo de energia elétrica associado às operações de bombeamento. Para lidar com a natureza dinâmica e aleatória da demanda por água, foram propostos modelos de programação estocástica de dois estágios com recurso, em que a variável aleatória é representada por um conjunto finito de realizações ou cenários. Os modelos matemáticos desenvolvidos são extensões de modelos determinísticos da literatura e refletem a suposição básica de que é possível se incorrer em um custo fixo pelas atividades de liga/desliga das bombas hidráulicas. Para controlar as violações das restrições de demanda por água na presença de múltiplos cenários diferentes, considerou-se também uma técnica de robustez na tentativa de gerar soluções quase factíveis. Por último, mas não menos importante, adotou-se um critério de aversão ao risco denominado desvio médio absoluto para obter custos de segundo estágio menos dependentes das realizações dos cenários. Os cenários foram gerados de acordo com um procedimento baseado em simulação Monte-Carlo que pode utilizar qualquer distribuição de probabilidade para produzir as probabilidades empíricas das variáveis aleatórias. Como o problema de programação de bombas com custo fixo proposto é um programa inteiro misto 0−1 estocástico, desenvolve-se uma heurística híbrida eficiente para obter soluções de boa qualidade de instâncias práticas em um tempo computacional plausível. Os resultados evidenciam a estabilidade do método de geração de cenários, a sensibilidade da solução de acordo com parâmetros-chave do modelo matemático, e a eficiência da heurística na resolução de instâncias de grande porte. Finalmente, foi demonstrado que é possível poupar recursos pela resolução do modelo de programação estocástica, em vez de adotar abordagens mais simples baseadas no valor esperado.

Advances in information technology in the past two decades have seen innovations in the field of domestic and industrial computing that led to a paradigm shift in the management and operation of urban water systems by water utility companies. The traditional public management policy that focused on ensuring a minimum quality of service regardless of the costs associated with the processes of catchment, treatment and distribution of water, in many cases even unknown, have evolved towards more efficient cost sensitive models. These new wholly or partly public funded management systems improve not only the quality of service offered to users, but also optimize resources by reducing the cost and causing the minimum environmental impact. The new challenges raised by the European Water Framework1 Directive by imposing cost recovery to improve water efficiency and environmental sustainability have led to a significant change at all levels of water management. Consequently, new priorities have been established in terms of infrastructure management that require the reduction of water losses and the improvement of the water efficiency in urban networks for human consumption. Likewise, in a broader context which includes the water--energy binomial, it is also desirable to improve the energy efficiency and carbon emissions of these systems. Today, network sectoring is the most commonly used strategy to improve management and increase network performance. It basically consists of dividing the network into several smaller hydraulic sectors, where water inlets and outlets are perfectly controlled. This simplifies the task of carrying out periodic water balances in each of the sectors, and allows water loss volume to be assessed for a given period of time. As configuring network sectors is not a trivial task, it is therefore important to have appropriate tools to perform the task efficiently and effectively. Mathematical models can play an important role as decision support tools to help water managers assess the performance of water network distribution systems. This thesis aims to address the current problems of managing urban water networks by combining new information-processing technologies with innovative network modelling techniques. It intends to facilitate the system diagnosis and extend the use of models on the decision-making process to provide better solutions to the management of urban water networks. For this purpose a software extension that works on a geographic information system (GIS) has been developed. It integrates: the hydraulic and water quality simulation program EPANET 2, innovative tools for model analysis and diagnostic, automatic tools for sectoring and computing tools to conduct water balances in the sectors using actual measurements. The work demonstrates the compatibility and complementarity of GIS and hydraulic models as technologies that can be used to support the assessment and diagnosis of water distribution networks. Considering that the majority of information linked to the network system has some geographic reference, it is not surprising that GIS has become a popular tool for dealing with such information. At the same time, the integration of mathematical modelling and simulation tools, offers the GIS a new dimension in the realm of hydraulic study of water networks. Furthermore, if this specific integration is provided with new features aimed not only to facilitate the model building, but also to assist the user in decision-making using powerful algorithms based on the application of the graph theory, the result is a powerful up-to-date analytical tool, which opens up new possibilities in the field of management and efficient operation of urban water supply systems. / Bartolín Ayala, HJ. (2013). Confección de modelos de redes de distribución de agua desde un Sig y desarrollo de herramientas de apoyo a la toma de decisiones [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/33152 / TESIS