This thesis will focus on a major Swedish city, Karlstad. The study uses a combined method consisting of a content analysis and semi-structured interviews. The qualitative content analysis is based on categorizing ongoing detailed plans for housing development in Karlstad. The respondents in the semi-structured interviews consist of people active in real estate development in Karlstad, the current chairman of the urban planning committee in Karlstad, and another politician with experience of urban planning. The purpose of the thesis is to investigate the development pattern in the housing sector in a Swedish city. This in connection with investigating how the cooperation between local actors works regarding housing development. In the next step, the purpose is operationalized by studying Karlstad as a case. The section on previous research presents relevant research on the topic of development in the housing sector. The theory chapter provides the theoretical framework for the study. A theoretical model regarding how development is achieved in the housing sector is central, the model summarizes various factors that contribute to achieving development. The results section presents the respondents' experience of how housing planning looks like in Karlstad and how cooperation works between different local actors. How Karlstad is growing with a focus on both densification and expansion in the city is central to the empirical data. A central part of the empirical data is that there is a picture of differing opinions on how cooperation looks between different local actors. One conclusion reached is that Karlstad works for an inclusive and varied densification while the city is expanding. Another conclusion that can be reached is that sustainability thinking in terms of social, economic and ecological aspects is to some extent guiding contemporary housing planning but will become even more important in the future. The main research question relevant to this thesis is: What is the pattern of development in the housing sector in Karlstad? / I denna uppsats är en svensk större stad i fokus, Karlstad. I studien används en kombinerad metod som består av en kvalitativ innehållsanalys och semistrukturerade intervjuer. Den kvalitativa innehållsanalysen utgår från att kategorisera pågående detaljplaner gällande bostadsutveckling i Karlstad. Respondenterna i de semistrukturerade intervjuerna utgörs av tre personer verksamma inom fastighetsutveckling i Karlstad. Dessutom har den nuvarande ordförande för stadsbyggnadsnämnden i Karlstad och en annan politiskt aktiv person med erfarenhet från stadsbyggnad intervjuats. Syftet med uppsatsen är att undersöka exploateringsmönstret i bostadssektorn i en större svensk stad. Detta i samband med att undersöka hur samarbetet mellan lokala aktörer fungerar gällande bostadsutveckling. I nästa led operationaliseras syftet genom att studera Karlstad som fall. I avsnittet gällande tidigare forskning presenteras relevant forskning kring ämnet exploatering. Teorikapitlet utgör det teoretiska ramverket för studien. En teoretisk modell gällande hur en exploatering nås är central och modellen sammanfattar olika faktorer som möjliggör exploatering av bostäder. I resultatdelen presenteras respondenternas upplevelse av hur bostadsplaneringen ser ut i Karlstad och hur samarbetet fungerar mellan olika aktörer. Hur Karlstad växer med fokus på att det både sker en förtätning i staden och en expansion av staden är centralt i empirin. En central del i empirin är att det finns en bild av att det finns åsikter som skiljer sig åt kring hur samarbetet ser ut mellan olika lokala aktörer. En slutsats som nås är att Karlstad verkar för en inkluderande och varierande förtätning samtidigt som staden expanderar. En annan slutsats som går att nå är att hållbarhetstänket ur sociala, ekonomiska och ekologiska aspekter är till viss del vägledande i nutida bostadsplanering men kommer i framtiden att bli ännu viktigare. Den huvudsakliga forskningsfrågan som är aktuell i detta uppsatsskrivande är: Hur ser mönstret av exploatering ut i bostadssektorn i Karlstad?

Alors que les bienfaits des parcs et espaces verts sont largement démontrés dans la littérature, la pandémie de COVID-19 a mis en lumière la nécessité de ces espaces auprès de la population, notamment en milieux urbains denses. Malgré cela, des recherches indiquent que dans les villes où la densité est importante, ces dernières peinent à offrir une quantité suffisante de ces espaces à leurs citoyens. Des recherches illustrent le rôle clé des outils d’aménagement et d’urbanisme pour planifier l’offre en parcs et espaces verts dans un contexte de densification urbaine, mais sans offrir de réponse complète quant aux façons dont les municipalités devraient utiliser ou combiner ces outils. Alors que le Québec a planifié la consolidation des municipalités déjà développées pour accueillir la croissance démographique anticipée, les outils qu’il met à la disposition des municipalités et la façon dont elles les utilisent pourront-ils lui permettre de planifier adéquatement l’offre en parcs et espaces verts dans ces milieux à densifier ? En s’appuyant sur la perspective de 15 professionnels de l’aménagement œuvrant pour des municipalités québécoises, cette recherche approfondit l’utilisation et l’influence des outils d’aménagement et d’urbanisme sur la planification de l’offre en parcs et espaces verts dans les milieux à consolider. La recherche a pour objectif de comprendre de quelles façons ces espaces sont planifiés, quels sont les outils utilisés, les pratiques porteuses et les facteurs de succès. Les résultats suggèrent que les outils québécois peuvent permettre aux municipalités de planifier adéquatement les parcs et espaces verts de leurs citoyens s’ils sont utilisés en synergie, en support à la négociation, et de manière concertée et innovante. Toutefois, les défis pour y arriver demeurent nombreux. Cette recherche contribue à l’avancée des connaissances en documentant la création de parcs et espaces verts dans un contexte de consolidation et de densification d’espaces urbains au Québec. Elle permet également de conscientiser les acteurs à l’importance et aux enjeux des parcs et espaces verts et aux spécificités des outils et des pratiques existantes en amont de la consolidation urbaine à venir. / While the benefits of parks and greenspaces are widely demonstrated in the literature, the COVID-19 pandemic has highlighted the need for these spaces among the population, particularly in dense urban environments. Despite this, research indicates that cities with high densities struggle to provide adequate amounts of these spaces to their citizens. Research illustrates the key role of planning and development tools in planning the supply of parks and greenspaces in the context of urban densification but does not provide a comprehensive answer as to how municipalities should use or combine these tools. While Quebec has planned the consolidation of already developed municipalities to accommodate anticipated population growth, will the tools it makes available to municipalities and the way they use them allow it to adequately plan the supply of parks and green spaces in these densifying environments? Based on the perspective of 15 planning professionals working for Quebec municipalities, this research examines the use and influence of planning tools on the planning of parks and green spaces in areas to be consolidated. The objective of the research is to understand how these spaces are planned, what tools are used, what practices are effective and what factors contribute to their success. The results suggest that Quebec's tools can enable municipalities to adequately plan parks and greenspaces if they are used in synergy, in support of negotiation, and in a concerted and innovative manner. However, the challenges to achieve this remain numerous. This research contributes to the advancement of knowledge by documenting the creation of parks and greenspaces in a context of consolidation and densification of urban spaces in Quebec. It also allows us to raise awareness of the importance of parks and greenspaces and the specificities of the existing tools and practices upstream of the urban consolidation to be carried out.

Densification of rice straw such as compacting and pelletizing is an important process to increase the density of rice straw resulting in a reduction of transportation cost. Within this research, we conducted a techno-economic investigation of rice straw densification to produce compressed bales and pellets, which are later used for animal feed. In line with the main deliverable of the performance of rice straw compacting and pelletizing processes, we also looked into the quality of the product in terms of uptake and digestibility of the cattle feed which could be improved by adding amendments such as urea during the compacting process. The compacting technology resulted in a 400% increase of bale density (from 94 to 390 kg.m-3). This could reduce transportation costs by about 60% for a 60 km driving distance using trucks. The net profit that resulted from compacted bales was USD 0.0062 kg-1. Although the pelletizing technology increased the cost of the densified product by 40–50%, its density increases by 700%, from 94 to 666 kg.m-3. The enriched-rice straw pellets contained 12.1% protein, 2.8% lipid, 32.7% raw fibre, and 11.2% ash. In addition, a test of this product for cattle feeding illustrated an increase in its eating desirability for cows. Findings from this study contribute to reducing feedstock cost and developing densified rice straw products. These, therefore, provide more alternative options to increase the benefits from rice production and thus, reduce the unsustainable burning of rice straw in the field. / Nén ép rơm là quá trình quan trọng và cần thiết để tăng khối lượng thể tích với mục đích giảm chi phí vận chuyển. Trong nghiên cứu này, chúng tôi đã thực hiện nghiên cứu đánh giá tính khả thi về kỹ thuật và kinh tế đối với nội dung nén ép rơm cuộn và ép viên rơm. Cùng với mục đích chính là tăng dung trọng của sản phẩm từ rơm, chúng tôi cũng đánh giá chất lượng sản phẩm làm thức ăn cho bò giúp cho tăng kích thích quá trình tiêu hóa. Kết quả nén ép cuộn rơm đã làm tăng dung trọng của kiện rơm đến 400% (từ 94 đến 398.7 kg.m-3). Qua đó, đã giảm được chi phí vận chuyển 60% được ước tính cho 60 km khoảng cách vận chuyển. Đối với ép viên rơm, dung trọng tăng đến 700% (từ 94 đến 666 kg.m-3). Hàm lượng dinh dưỡng của viên nén hỗn hợp rơm gồm protein (12,1%), chất béo (2,8%), chất xơ (32,7%), và lượng tro tổng (11,2%). Ngoài ra, kết quả thử nghiệm cho bò ăn sản phẩm viên nén này cho thấy bò có cảm giác thích và ăn hết toàn bộ viên nén. Kết quả của nghiên cứu đã góp phần giảm chi phí khi sản xuất thức ăn cho bò, tăng thu nhập cho người nông dân và từ đó giảm tác động môi trường do việc đốt rơm trên đồng.

Contribution of daylight to employees in terms of health, productivity, and overall wellness in the office spaces are undeniable. Apart from the psychological and biological benefits of employees, embracing daylight in office spaces increases the energy-efficiency of the building which leads to the sustainable development of a city. However, a considerable number of employees in Sweden lack daylight in their workspaces according to a report by the Swedish Work Environment Authority [Arbetsmiljöverket (Swedish)] (Lowden, 2019). Professionals like Architects, Lighting Designers, and students of architecture and lighting design across Sweden were asked their opinions pertaining to lack of daylight in a considerable number of office spaces in Sweden based on their experience through online questionnaires/ interviews to get to know the overview of this subject. Out of all the possible reasons, window design and economy were the two macro factors according to them that influenced daylight in an office building in Sweden but often, obstruction angle in a building due to urban densification is overlooked when it comes to daylight in an office building. This thesis discusses the influence of obstruction angles with an illustrated office building in Stockholm. Diva for Rhino was the software used for the modelling and daylight simulation.

Målet med studien är att med hjälp av multikriterieanalyser hitta platser i Gävle tätort att anlägga fickparker på. Till en början gjordes en litteraturöversikt som bland annat bidrog med uppfattningen om vad som är viktigt för fickparker och vilka kriterier som är användbara för att hitta platser att anlägga fickparker på. Utifrån denna uppfattning samt intervjuer valdes kriterierna. Kriterierna skapades i form av restriktioner och faktorer i programmet ESRI ArcGIS 10.2. Intervjuer genomfördes med tre sakkunniga personer. Respondenterna rangordnade och diskuterade kriterierna utifrån vad de ansåg var minst respektive mest viktigt vid anläggandet av fickparker. Rangordningarna blev underlag till viktning av kriterierna (enligt rank-sum-weights). En känslighetsanalys genomfördes också för att testa kriterierna mot fler uppsättningar av vikter. Resultatet av analyserna redovisas på tre kartor baserat på en egen rangordning samt respondenternas. Kartorna visar de bästa platserna att anlägga fickparker på enligt respektive rangordning. Skillnader finns mellan kartorna, men oavsett hur kriterierna rangordnades blev ungefär samma platser valda som de bästa att anlägga fickparker på. De tre bästa platserna som är gemensamma för alla tre rangordningar är alla lokaliserade på Norr (norr om Gavleån). Resultatet av analysen visade att platser som inte på förhand är uppenbara kan bli valda som lämpliga för fickparker. / The purpose of this study is to locate places in Gävle to create pocket parks in, using multi criteria analyzes. Initially a literature review was made that, among other things, contributed with an understanding of what is important to pocket parks and which criteria that is useful in order to locate places to create pocket parks in. The criteria were chosen based on that understanding and interviews. The criteria were produced in the form of constraints and factors in ESRI ArcGIS 10.2. Interviews were conducted with three experts in the field. The interviewees ranked and discussed the criteria based on what they considered to be least and most important in the creation of pocket parks. Weighting of the criteria was based on the gathered rankings (using rank-sum-weights). A sensitivity analysis was conducted to test the criteria against more sets of weights. The results from the analyzes are presented on three maps based on a self-made rank as well as the ones that the interviewees made. The maps show the best locations to create pocket parks in accordance to each rank. There are differences between the maps, but approximately the same locations are chosen as the best ones no matter how the criteria were ranked. The three best locations that the ranks have in common are all located in Norr (north of Gavleån). The results from the analysis demonstrate that locations that pre-analysis aren’t obvious can be chosen as suitable for the creation of pocket parks.

I hela landet expanderas städerna alltmer till följd av ökad befolkningsmängd. Utvecklingen gerupphov till bostadsbrist och kräver större och modernare infrastruktur i städerna. Markytan behöverdå utnyttjas för etablering av ny infrastruktur och nya bostäder. Då markytan redan är begränsaduppstår ett dilemma i detta sammanhang. Vad ska prioriteras, produktionen av bostäder ellerutveckling av infrastruktur? Ett förslag på lösning till det avsedda problemet är att bostadsbristen kan täckas av ett specifiktkoncept där bostadsproduktionen inte kräver arbete på den begränsade markytan. Lösningen kallaspåbyggnad och innebär byggnation ovanför en befintlig byggnad. Man utnyttjar det fria utrymmetovanför byggnaden istället för att bygga i sidled - tillbyggnad - dvs. byggnation på marken. Detta examensarbete utgör en fallstudie om förtätning av befintliga höghus mha. påbyggnad. Specifiktprojekteringsskedet i byggprocessen för påbyggnad behandlas. I projekteringsskedet utreds bl.a.ämnena geoteknik, stadsplanering, arkitektur, miljö och konstruktionsteknik. Dessa ämnen studeras idenna fallstudie. Avsikten med forskningen är att mha. dessa utredda ämnen, klargöra varförpåbyggnad kan lösa urbana omständigheter som rådande bostadsbrist.Denna fallstudie är baserad på kvalitativ forskning. Insamling av vetenskapligt stoff har skett genombåde litteratursökning och webbaserad sökning. / Throughout Sweden, the cities expand due to increased population. The expansion causes housing shortage and the need for larger infrastructure especially in larger cities where the ground surface is more limited and restricted. These circumstances cause a dilemma as to whether the establishment of new infrastructure or new residential apartments should be prioritized, basically the establishment of new infrastructure vs. the establishment of new residential apartments.   A suggestion of a solution for this case is vertical building extension implying to build above an existing building without any utilization of the ground surface being required or needed. The empty space above an existing building, whether it is a high rise building or a single-family house, is being turned to advantage for expansion of the floor area.  This concept is an alternative to horizontal building extension. Unlike vertical building extension, it requires utilization of the ground surface and is therefore not suitable for this case. This thesis constitutes a case study covering the projecting phase in the building process of vertical building extension of storeys on existing high-rise buildings located in large cities such as Stockholm. Vertical building extension is presented as a solution for densification of large cities. There are several subjects which are investigated in the projecting phase. Architecture, urban planning, geotechnics, building construction and sustainability are a few of the subjects and these are specifically investigated in this case study.  The aim with this paper is through the mentioned investigation, to clarify why vertical building extension could be a solution for urban circumstances like housing shortage. This case study is based on qualitative research. Collection of scientific information has been done through both literature research and online research.

Housing in prosperous American cities is becoming increasingly expensive, forcing many municipal governments to re-evaluate how they will continue to serve lower-income residents and ensure equitable access to housing and resources. In the City of Alexandria, the Alexandria Re-Development and Housing Authority (ARHA) has worked in recent years to partner with private developers to convert its existing stock of low-density, designated-affordable housing into more dense, mixed-income communities. This is possible because many of its existing communities sit on land in now-prime locations where the City currently allows the most density, as well as bonus density through a variety of mechanisms. While these projects have succeeded to some extent, the City is unfortunately still seeing a rapid rise in rents accompanied by a rapid decrease in available affordable housing of all types, in both privately-developed and publicly-subsidized communities. Increasing income disparity is also simultaneously driving lower-income to middle-class residents to suburban and exurban sites where limited access to municipal resources and public transportation can be highly detrimental to quality of life. While additional density is the knee-jerk response to many of affordability's challenges, often the resulting built solutions seem incomplete – achieving the basic goal of housing more residents, but failing to build thriving and diverse communities that connect people the way previous communities may have. After all, the pragmatics of building generally point towards maximizing square footage, monetary return, and speed of delivery by using conventional and commonly-accepted solutions, with less energy given to resident outcomes, and how people might be affected by the change to their living environments and communities. As Jan Gehl and Jane Jacobs examined in Cities for People and The Death and Life of Great American Cities respectively, simple pragmatics do not make for livable environments. A truly humanist approach to design for living in cities requires not only good policy, practice, and engagement, but also architectural strategies that respond to how humans relate to each other and their surroundings. Convergence explores how designers can contribute to making urban housing better for everyone by addressing housing affordability, person-to-person interaction, and community engagement in increasingly-dense environments. Its primary objectives are: • Encouraging neighborliness by increasing chance encounters as well as reducing the sharp threshold between private and public space often found in apartment-style buildings. • Increasing the visibility of human activity to the street in a multi-floor, multi-family project. • Using new mass timber methods and modularity to improve initial building construction and cost while also incorporating sustainable practices to reduce resource use and operating cost. • Anticipating that modification and reconfiguration will be required in the future, and offering defined parameters to simplify that process. • Creating a variety of unit sizes while also offering future flexibility to respond to changing community needs. • Combining the familiar with the novel to connect the new community to its surroundings, bridge experiences, and manage change. / Master of Architecture / In the City of Alexandria, the Alexandria Re-Development and Housing Authority (ARHA) owns several affordable housing sites in desirable locations that it has been working to convert into more dense, mixed-income housing in partnership with private developers. While these projects have succeeded to some extent, housing in the City continues to become increasingly expensive, and wages for low-income and lower-middle class residents are not keeping pace with the increase in cost of living. This phenomenon is pushing many long-time and/or lower-wage residents to the suburbs and exurbs, limiting access to municipal resources and public transportation, and reducing quality of life. As a result, communities and families with long histories in the City are breaking apart and dispersing. Many advocates, policymakers, designers, and developers have turned to additional density as the most immediate response to these concerns. However, additional density isn’t enough; new buildings may house more people, but fail to address the other aspects of building thriving and diverse communities that connect people the way previous communities may have. Good housing and good communities need more than square footage, so it is time to look beyond conventional solutions. New approaches are needed to respond to how people are affected by changes to their living environments and communities, and create the kinds of positive outcomes that should be part of any new housing project. Therefore, if we want to design for living in cities, we have to have good policies, practices, and engagement, but we also need architectural strategies that respond to how humans relate to each other and their surroundings. Convergence explores how designers can contribute to making urban housing better for everyone by addressing housing affordability, person-to-person interaction, and community engagement in increasingly-dense environments. Its primary objectives are: • Encouraging neighborliness by increasing chance encounters as well as reducing the sharp threshold between private and public space often found in apartment-style buildings. • Increasing the visibility of human activity to the street in a multi-floor, multi-family project. • Using new mass timber methods and modularity to improve initial building construction and cost while also incorporating sustainable practices to reduce resource use and operating cost. • Anticipating that modification and reconfiguration will be required in the future, and offering defined parameters to simplify that process. • Creating a variety of unit sizes while also offering future flexibility to respond to changing community needs. • Combining the familiar with the novel to connect the new community to its surroundings, bridge experiences, and manage change.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal. / L'étalement urbain est un phénomène de croissance urbaine non planifiée qui a des conséquences lourdes sur les municipalités et sur les ressources naturelles. Soucieux de la protection des écosystèmes naturels et du partage équitable de ces ressources entre les générations présentes et futures, le développement durable se trouve au centre des débats politiques et urbains. N'étant pas épargnée par cette croissance urbaine sous forme de tâche d'huile et les maux qu'elle engendre, la Municipalité Régionale d'Ottawa-Carleton (MROC) essaie de contrôler et de contenir sa croissance urbaine à l'intérieur des limites urbaines qu'elle s'est, au préalable, fixées tout en veillant sur l'utilisation modérée et efficace des ressources naturelles dont elle dispose. Sa principale politique, pour atteindre cet objectif et en vue du développement durable, consiste à initier au sein de ses localités la densification résidentielle. Politique vaste et complexe, la densification résidentielle se heurte aux idées préconçues de certains administrateurs politiques et urbains, des développeurs et de la population de la banlieue qui l'assimilent à tort à la surpopulation ou à l'existence trop intense du volume et des formes de constructions sur une surface spécifique du sol. Notre préoccupation consiste à vérifier la part de la densification à l'arrêt de l'étalement urbain et au développement durable. Notre objectif vise avant tout à comprendre la densification dans Ottawa-Carleton. Quels avantages lui offre-t­elle? Comment contribue-t-elle à l'arrêt de l'étalement urbain ? En quoi peut-on la juger comme durable ? Pour beaucoup, la densification est souvent accompagnée d'une réduction des coûts publics et des coûts privés indirects. Quels sont les éléments qui permettent d'aboutir à cette conclusion ? Pour mener à bien notre étude, nous nous sommes référées à plusieurs sources de renseignements. Notre méthode de recherche est constituée d'une étude empirique et d'une étude théorique qui nous ont permis d'aborder les problèmes que nous soulevons, et ont contribué à la réalisation d'objectifs de recherche. L'étude théorique était composée de la littérature qui existe et qui traite des sujets que nous avons retenus. Ce sont des documents d'urbanisme et d'aménagement, notamment les plans officiels, les documents de géographie, les revues d'urbanisme, les rapports des services d'urbanisme, les rapports d'experts­conseils, les brochures, les bulletins, les rapports de recherche. L'étude empirique comprenait une entrevue réalisée avec Madame Sylvie Grenier (Urbaniste Intermédiaire à la MROC), et une observation de terrain effectuée à l'intérieur de trois villes de la MROC. Ces deux outils de recherche nous ont permis de recenser les priorités et les stratégies de la MROC en matière de densification résidentielle. Finalement, nous retenons que la densification résidentielle est une politique qui vise l'organisation et la rationalisation des villes. De toute évidence, son introduction au sein d'une municipalité doit être accompagnée de mesures ou réglementations strictes de l'utilisation des sols. Ces mesures doivent en principe laisser transparaître l'objectif poursuivi par la municipalité qui adopte la densification résidentielle. Dans le cas de la MROC le but poursuivi en premier consiste à répondre à la demande de la croissance urbaine future de la Région dans une optique de développement durable.

A new communication paradigm is foreseen for beyond 2020 society, due to the emergence of new broadband services and the Internet of Things era. The set of requirements imposed by these new applications is large and diverse, aiming to provide a ubiquitous broadband connectivity. Research community has been working in the last decade towards the definition of the 5G mobile wireless networks that will provide the proper mechanisms to reach these challenging requirements. In this framework, three key research directions have been identified for the improvement of capacity in 5G: the increase of the spectral efficiency by means of, for example, the use of massive MIMO technology, the use of larger amounts of spectrum by utilizing the millimeter wave band, and the network densification by deploying more base stations per unit area. This dissertation addresses densification as the main enabler for the broadband and massive connectivity required in future 5G networks. To this aim, this Thesis focuses on the study of the UDN. In particular, a set of technology enablers that can lead UDN to achieve their maximum efficiency and performance are investigated, namely, the use of higher frequency bands for the benefit of larger bandwidths, the use of massive MIMO with distributed antenna systems, and the use of distributed radio resource management techniques for the inter-cell interference coordination. Firstly, this Thesis analyzes whether there exists a fundamental performance limit related with densification in cellular networks. To this end, the UDN performance is evaluated by means of an analytical model consisting of a 1-dimensional network deployment with equally spaced BS. The inter-BS distance is decreased until reaching the limit of densification when this distance approaches 0. The achievable rates in networks with different inter-BS distances are analyzed for several levels of transmission power availability, and for various types of cooperation among cells. Moreover, UDN performance is studied in conjunction with the use of a massive number of antennas and larger amounts of spectrum. In particular, the performance of hybrid beamforming and precoding MIMO schemes are assessed in both indoor and outdoor scenarios with multiple cells and users, working in the mmW frequency band. On the one hand, beamforming schemes using the full-connected hybrid architecture are analyzed in BS with limited number of RF chains, identifying the strengths and weaknesses of these schemes in a dense-urban scenario. On the other hand, the performance of different indoor deployment strategies using HP in the mmW band is evaluated, focusing on the use of DAS. More specifically, a DHP suitable for DAS is proposed, comparing its performance with that of HP in other indoor deployment strategies. Lastly, the presence of practical limitations and hardware impairments in the use of hybrid architectures is also investigated. Finally, the investigation of UDN is completed with the study of their main limitation, which is the increasing inter-cell interference in the network. In order to tackle this problem, an eICIC scheduling algorithm based on resource partitioning techniques is proposed. Its performance is evaluated and compared to other scheduling algorithms under several degrees of network densification. After the completion of this study, the potential of UDN to reach the capacity requirements of 5G networks is confirmed. Nevertheless, without the use of larger portions of spectrum, a proper interference management and the use of a massive number of antennas, densification could turn into a serious problem for mobile operators. Performance evaluation results show large system capacity gains with the use of massive MIMO techniques in UDN, and even greater when the antennas are distributed. Furthermore, the application of ICIC techniques reveals that, besides the increase in system capacity, it brings significant energy savings to UDNs. / A partir del año 2020 se prevé que un nuevo paradigma de comunicación surja en la sociedad, debido a la aparición de nuevos servicios y la era del Internet de las cosas. El conjunto de requisitos impuesto por estas nuevas aplicaciones es muy amplio y diverso, y tiene como principal objetivo proporcionar conectividad de banda ancha y universal. En las últimas décadas, la comunidad científica ha estado trabajando en la definición de la 5G de redes móviles que brindará los mecanismos necesarios para garantizar estos requisitos. En este marco, se han identificado tres mecanismos clave para conseguir el necesario incremento de capacidad de la red: el aumento de la eficiencia espectral a través de, por ejemplo, el uso de tecnologías MIMO masivas, la utilización de mayores porciones del espectro en frecuencia y la densificación de la red mediante el despliegue de más estaciones base por área. Esta Tesis doctoral aborda la densificación como el principal mecanismo que permitirá la conectividad de banda ancha y universal requerida en la 5G, centrándose en el estudio de las Redes Ultra Densas o UDNs. En concreto, se analiza el conjunto de tecnologías habilitantes que pueden llevar a las UDNs a obtener su máxima eficiencia y prestaciones, incluyendo el uso de altas frecuencias para el aprovechamiento de mayores anchos de banda, la utilización de MIMO masivo con sistemas de antenas distribuidas y el uso de técnicas de reparto de recursos distribuidas para la coordinación de interferencias. En primer lugar, se analiza si existe un límite fundamental en la mejora de las prestaciones en relación a la densificación. Con este fin, las prestaciones de las UDNs se evalúan utilizando un modelo analítico de red unidimensional con BSs equiespaciadas, en el que la distancia entre BSs se disminuye hasta alcanzar el límite de densificación cuando ésta se aproxima a 0. Las tasas alcanzables en redes con distintas distancias entre BSs son analizadas, considerando distintos niveles de potencia disponible en la red y varios grados de cooperación entre celdas. Además, el comportamiento de las UDNs se estudia junto al uso masivo de antenas y la utilización de anchos de banda mayores. Más concretamente, las prestaciones de ciertas técnicas híbridas MIMO de precodificación y beamforming se examinan en la banda milimétrica. Por una parte, se analizan esquemas de beamforming en BSs con arquitectura híbrida en función de la disponibilidad de cadenas de radiofrecuencia en escenarios exteriores. Por otra parte, se evalúan las prestaciones de ciertos esquemas de precodificación híbrida en escenarios interiores, utilizando distintos despliegues y centrando la atención en los sistemas de antenas distribuidos o DAS. Además, se propone un algoritmo de precodificación híbrida específico para DAS, y se evalúan y comparan sus prestaciones con las de otros algoritmos de precodificación utilizados. Por último, se investiga el impacto en las prestaciones de ciertas limitaciones prácticas y deficiencias introducidas por el uso de dispositivos no ideales. Finalmente, el estudio de las UDNs se completa con el análisis de su principal limitación, el nivel creciente de interferencia en la red. Para ello, se propone un algoritmo de control de interferencias basado en la partición de recursos. Sus prestaciones son evaluadas y comparadas con las de otras técnicas de asignación de recursos. Tras este estudio, se puede afirmar que las UDNs tienen gran potencial para la consecución de los requisitos de la 5G. Sin embargo, sin el uso conjunto de mayores porciones del espectro, adecuadas técnicas de control de la interferencia y el uso masivo de antenas, las UDNs pueden convertirse en serios obstáculos para los operadores móviles. Los resultados de la evaluación de prestaciones de estas tecnologías confirman el gran aumento de la capacidad de las redes mediante el uso masivo de antenas y la introducción de mecanismos de I / A partir de l'any 2020 es preveu un nou paradigma de comunicació en la societat, degut a l'aparició de nous serveis i la era de la Internet de les coses. El conjunt de requeriments imposat per aquestes noves aplicacions és ampli i divers, i té com a principal objectiu proporcionar connectivitat universal i de banda ampla. En les últimes dècades, la comunitat científica ha estat treballant en la definició de la 5G, que proveirà els mecanismes necessaris per a garantir aquests exigents requeriments. En aquest marc, s'han identificat tres mecanismes claus per a aconseguir l'increment necessari en la capacitat: l'augment de l'eficiència espectral a través de, per exemple, l'ús de tecnologies MIMO massives, la utilització de majors porcions de l'espectre i la densificació mitjançant el desplegament de més estacions base per àrea. Aquesta Tesi aborda la densificació com a principal mecanisme que permetrà la connectivitat de banda ampla i universal requerida en la 5G, centrant-se en l' estudi de les xarxes ultra denses (UDNs). Concretament, el conjunt de tecnologies que poden dur a les UDNs a la seua màxima eficiència i prestacions és analitzat, incloent l'ús d'altes freqüències per a l'aprofitament de majors amplàries de banda, la utilització de MIMO massiu amb sistemes d'antenes distribuïdes i l'ús de tècniques distribuïdes de repartiment de recursos per a la coordinació de la interferència. En primer lloc, aquesta Tesi analitza si existeix un límit fonamental en les prestacions en relació a la densificació. Per això, les prestacions de les UDNs s'avaluen utilitzant un model analític unidimensional amb estacions base equidistants, en les quals la distància entre estacions base es redueix fins assolir el límit de densificació quan aquesta distància s'aproxima a 0. Les taxes assolibles en xarxes amb diferents distàncies entre estacions base s'analitzen considerant diferents nivells de potència i varis graus de cooperació entre cel·les. A més, el comportament de les UDNs s'estudia conjuntament amb l'ús massiu d'antenes i la utilització de majors amplàries de banda. Més concretament, les prestacions de certes tècniques híbrides MIMO de precodificació i beamforming s'examinen en la banda mil·limètrica. D'una banda, els esquemes de beamforming aplicats a estacions base amb arquitectures híbrides és analitzat amb disponibilitat limitada de cadenes de radiofreqüència a un escenari urbà dens. D'altra banda, s'avaluen les prestacions de certs esquemes de precodificació híbrida en escenaris d'interior, utilitzant diferents estratègies de desplegament i centrant l'atenció en els sistemes d' antenes distribuïdes (DAS). A més, es proposa un algoritme de precodificació híbrida distribuïda per a DAS, i s'avaluen i comparen les seues prestacions amb les de altres algoritmes. Per últim, s'investiga l'impacte de les limitacions pràctiques i altres deficiències introduïdes per l'ús de dispositius no ideals en les prestacions de tots els esquemes anteriors. Finalment, l' estudi de les UDNs es completa amb l'anàlisi de la seua principal limitació, el nivell creixent d'interferència entre cel·les. Per tractar aquest problema, es proposa un algoritme de control d'interferències basat en la partició de recursos. Les prestacions de l'algoritme proposat s'avaluen i comparen amb les d'altres tècniques d'assignació de recursos. Una vegada completat aquest estudi, es pot afirmar que les UDNs tenen un gran potencial per aconseguir els ambiciosos requeriments plantejats per a la 5G. Tanmateix, sense l'ús conjunt de majors amplàries de banda, apropiades tècniques de control de la interferència i l'ús massiu d'antenes, les UDNs poden convertir-se en seriosos obstacles per als operadors mòbils. Els resultats de l'avaluació de prestacions d' aquestes tecnologies confirmen el gran augment de la capacitat de les xarxes obtingut mitjançant l'ús massiu d'antenes i la introducci / Giménez Colás, S. (2017). Ultra Dense Networks Deployment for beyond 2020 Technologies [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86204

No / Alpha phase sintering, sinter hardening, and mechanical properties of prealloyed Fe-1.5Mo base powder with and without additions of elemental Si, ferrosilicon, and carbon under various process conditions have been investigated. Liquid paraffin, as a new lubricating agent, was found to be useful in reducing segregation, interparticle and die wall frictions, as well as reducing ejection forces and die and tool wear. It was found that addition of Si to the base powder enhanced the sintering process by stabilisation of the ¿-phase and formation of two kinds of liquid phase at ~1045 and ~1180°C, corresponding to the solidus and liquidus temperatures, respectively. This addition increased the tensile strength of the as sintered Fe-1.5Mo from 174 to 445 MPa owing to massive solid solution strengthening effect of Si. An optimum sinter hardenable alloy, of composition Fe-1.5Mo + 3Si + 1.2C, provided a high sintered density of 7.55 g cm-3, tensile and bend strengths of 764 and 1405 MPa, respectively, with 2.5% elongation, after sintering at 1250°C for 1 h under hydrogen or vacuum using moderate cooling rates of ¿ 20 K min-1. Faster cooling rates caused brittleness and very low UTS for the high carbon steel. Full heat treatment improved the UTS by 200 MPa which was useful only for the high carbon steel with high cooling rates ¿ 30 K min-1. Depending on the cooling rate, the as sintered microstructures consisted of mainly fine or coarse pearlite, bainite, martensite, and some retained austenite with hardness in the range 250-720 HV10. Some proeutectoid grain boundary cementites were also present in the as sintered high carbon steel. This work, therefore, has shown that high densities with acceptable microstructures and good mechanical properties are achievable with single stage compaction and single sintering operations by using the optimum process conditions and alloying composition without the need for a post-sintering heat treatment.