This dissertation explores the theoretical and methodological implications involved in the policy framework needed to intensify urban residential areas in a developing country. Metropolitan Khartoum, Sudan, has been chosen as a case study. The aim of the study is to further our understanding of the implications of transforming a sprawling city form to an intensified form. The objectives are: to identify the factors that have shaped Sudanese urban form in general and Metropolitan Khartoum in specific; to identify the policies that can intensify the urban residential neighborhoods in Metropolitan Khartoum; and, to influence both the demand and requisite housing needs for this intensified form. This research is qualitative in its nature: the complexity of the study problematic required the adoption of a constructivist paradigm as the fundamental set of beliefs. Inductive arguments are used in conjunction with a wide range of methods, including detailed descriptions of Sudan and metropolitan Khartoum, with special emphasis on how local environment, urban challenges, policy, legislation and practices affect the study problematic. The theoretical premises of intensification are reviewed along with development issues, urban infrastructure challenges and opportunities in developing countries and local acceptability of intensification. The different forces that can shape urban forms have been described and the suitability of metropolitan Khartoum, with different general urban intensification policies and practices and of urban management tools in large African cities has been investigated. The outcome of the study provides detail for a discussion of results that work to explain some of the cause and effect of urban sprawl in Metropolitan Khartoum. It also suggests possible change in both policy and regulation to induce successful city reform towards intensification. / QC 20110121

<p>This dissertation explores the theoretical and methodological implications involved in the policy framework needed to intensify urban residential areas in a developing country. Metropolitan Khartoum, Sudan, has been chosen as a case study. The aim of the study is to further our understanding of the implications of transforming a sprawling city form to an intensified form. The objectives are: to identify the factors that have shaped Sudanese urban form in general and Metropolitan Khartoum in specific; to identify the policies that can intensify the urban residential neighborhoods in Metropolitan Khartoum; and, to influence both the demand and requisite housing needs for this intensified form. This research is qualitative in its nature: the complexity of the study problematic required the adoption of a constructivist paradigm as the fundamental set of beliefs. Inductive arguments are used in conjunction with a wide range of methods, including detailed descriptions of Sudan and metropolitan Khartoum, with special emphasis on how local environment, urban challenges, policy, legislation and practices affect the study problematic. The theoretical premises of intensification are reviewed along with development issues, urban infrastructure challenges and opportunities in developing countries and local acceptability of intensification. The different forces that can shape urban forms have been described and the suitability of metropolitan Khartoum, with different general urban intensification policies and practices and of urban management tools in large African cities has been investigated. The outcome of the study provides detail for a discussion of results that work to explain some of the cause and effect of urban sprawl in Metropolitan Khartoum. It also suggests possible change in both policy and regulation to induce successful city reform towards intensification.</p>

L'expansion des services en ligne, l'avènement du big data, favorisé par l'internet des objets et les terminaux mobiles, a entraîné une croissance exponentielle du nombre de centres de données qui fournissent des divers services de cloud computing. Par conséquent, la topologie du centre de données est considérée comme un facteur d'influence sur la performance du centre de données. En effet, les topologies des centres de données devraient offrir une latence faible, une longueur de chemin moyenne réduite avec une bande passante élevée. Ces exigences augmentent la consommation énergétique dans les centres de données. Dans cette dissertation, différentes solutions ont été proposées pour surmonter ces problèmes. Tout d'abord, nous proposons une nouvelle topologie appelée LCT (Linked Cluster Topology) qui augmente le nombre de nœuds, améliore la connexion réseau et optimise le routage des données pour avoir une faible latence réseau. Une nouvelle topologie appelée VacoNet (Variable connexion Network) a été également présentée. VacoNet offre un nouveau algorithme qui définit le exact nombre de port par commutateur pour connecter le nombre de serveurs requis tout en réduisant l'énergie consommée et les matériaux inutilisés (câbles, commutateurs). En outre, nous _étudions une nouvelle technique pour optimiser la consumation d'énergie aux centres de données. Cette technique peut périodiquement estimer la matrice de trafic et gérer l'_état des ports de serveurs tout en maintenant le centre de données entièrement connecté. La technique proposée prend en considération le trafic réseau dans la décision de gestion des ports. / Data centers (DC) are being built around the world to provide various cloud computing services. One of the fundamental challenges of existing DC is to design a network that interconnects massive number of nodes (servers)1 while reducing DC' cost and energy consumption. Several solutions have been proposed (e.g. FatTree, DCell and BCube), but they either scale too fast (i.e., double exponentially) or too slow. Effcient DC topologies should incorporate high scalability, low latency, low Average Path Length (APL), high Aggregated Bottleneck Throughput (ABT) and low cost and energy consumption. Therefore, in this dissertation, different solutions have been proposed to overcome these problems. First, we propose a novel DC topology called LCT (Linked Cluster Topology) as a new solution for building scalable and cost effective DC networking infrastructures. The proposed topology reduces the number of redundant connections between clusters of nodes, while increasing the numbers of nodes without affecting the network bisection bandwidth. Furthermore, in order to reduce the DCs cost and energy consumption, we propose first a new static energy saving topology called VacoNet (Variable Connection Network) that connects the needed number of servers while reducing the unused materials (cables, switches). Also, we propose a new approach that exploits the correlation in time of internode communication and some topological features to maximize energy saving without too much impacting the average path length.