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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Priority Aware Interference Mitigation Techniques for Coexistence of Wireless Technologies in Smart Utility Networks

Nahar, Badrun, Alam, Mohammad Shah, Shawkat, Shamim Ara, Hoque, Mohammad A. 21 November 2017 (has links)
In recent years, Smart Grid (SG) is envisioned to be the next generation electric power system by replacing traditional power grid due to its advantage of using two way communications. To implement reliable SG wireless communication networks, IEEE introduced a new wireless standard (IEEE802.15.4g) for Smart Utility Networks (SUNs). However, SUN operates on 2.4 GHz unlicensed band which is overlapped with Wireless Local Area Networks (WLANs) that leads to coexistence in Smart Utility Networks. In this paper, the coexistence problem of SUN is addressed in terms of homogeneous and heterogeneous interferences. To mitigate the homogeneous interference, Contention Access Period (CAP) and Contention Free Period (CFP) of a super frame of IEEE 802.15.4g is used to access the channel using slotted CSMA/CA algorithm by modifying the Backoff Period (BP) and Clear Channel Assessment (CCA) period for different priority data. An analytical model is developed using Markov chain, through which we demonstrate the accuracy of the proposed model in terms of throughput, channel access delay, probability of successful transmission and collision for nodes with different priority data. Performance evaluation is further investigated by comparing the proposed scheme with the existing PA-MAC. A channel switching mechanism is explored to mitigate the heterogeneous interference by the prediction of Naive Bayes Classifier. Predicted result shows that proposed mechanism effectively mitigates the heterogeneous interference by choosing the non-overlapping and non-coexisting channel.
2

2D and 3D Visualization to Support Fieldwork in the Area of Utility Networks

Gustafsson, Klas, Berg, Oskar January 2017 (has links)
Utility network fieldworkers of today want to access more information and can benefit a lot from new technical development. Today most fieldwork is conducted using paper plans or locally stored data on laptops as a visual aid. Therefore there is a need for improvement and development of new reliable software for fieldwork. Also the abil- ity to use advanced Geographic Information Systems (GIS) solutions and enhanced visualization methods while out in the field could help improve fieldwork. In order to be as e↵ective as possible when carrying out di↵erent tasks in the field, di↵erent ways of visualizing the same network data are required. 2D and 3D visualization methods have di↵erent advantages and disadvantages when it comes to visualizing network data, which will be accounted for in this thesis. There are three main objectives in this thesis. The first is to evaluate how suitable di↵erent visualization methods are for fieldwork users working with utility networks. The second is to get a better understanding of what hardware and software that can be used for implementing the visualization methods. The last one is to use the first and second objectives to develop a prototype for utility network fieldwork. To address the objectives, the first step is to understand the users that work in the field. By conducting interviews, information about the current workflow for fieldworkers and their opinions about how the systems currently work is gathered. Based on this information the thesis is divided into cases and criteria which is the foundation for proposing a solution in form of mock-up sketches which is then imple- mented in form of a prototype. Finally the prototype is evaluated quantitatively and qualitatively using a web survey and presentations for potential end users. The prototype is created using web technologies and is mainly intended for tablets. Because of its mobility, screen size and adequate computational power the tablet is a good hardware choice for conducting fieldwork. The prototype presents network data in a 2D interactive map view, a 3D augmented reality (AR) view and a combined view. These choices are based on information gathered by studying related work and performing interviews with potential end users in the beginning of the study. The results of the thesis highlights large possibilities in making field work more e↵ective for fieldworkers. This in concluded partly by the results of the interviews with potential end users, but also by the response of the survey and presentation of the suggested solution. It is shown that there are new ways to improve the work process out in the field and that AR can help in visualizing the network in a new informative way for fieldwork. However, several challenges remain, but rapid techno- logical development implies possible solutions to deal with these challenges.
3

Roteamento geográfico para redes de sensores e atuadores sem fio em redes urbanas de comunicação / Design of a hybrid geographical routing protocol for wireless sensor and actuator networks applied to smart utility networks

Denardin, Gustavo Weber 25 May 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Smart grids and smart utility networks are the next-generation utility networks that intend to provide efficient control and management of utilities such as electricity, natural gas, water and sewage. Communication technology is the essential element for enabling formation of networks where control messages and metering data can be exchanged. In this work it is shown that wireless sensor and actuator networks are suitable candidates to implement this intelligent networks. The main routing algorithms for this category of wireless network are investigated in order to verify its performance when applied to the characteristics of smart utility networks, which are mainly related for large scale networks formed by hundreds to thousands of devices. It is shown that geographic routing is one of the most suitable routing strategies for large scale wireless networks, due to its low overhead and high scalability features. Usually, a geographic routing scheme combines a geographic greedy forwarding with a recovery mechanism to solve the local minima problem. Solutions proposed in the literature commonly combine greedy forwarding with the well known face routing for achieving this goal. However, the average path length in number of hops produced by face routing could be much worse than the optimal topological path in most realistic scenarios. In this work, it is proposed a new intermediate procedure between the geographic greedy mode and the recovery mode in order to improve routing efficiency in number of hops, without network overhead. It exploits the optimal topological route to base stations, obtained by beacon messages, as a resource to find better routes than the ones created by face routing. It is shown by simulations that the proposed hybrid approach leads to a significant improvement of routing performance when applied to combined greedy-face routing algorithms. Furthermore, experimental results obtained through testbeds shown that the proposed maintenance procedures are capable of avoid uctuations in the network infrastructure, providing robust routes for packet forwarding in large scale networks. / Smart grids e redes urbanas de comunicação formam a próxima geração de redes que pretende fornecer controle e gestão é eficiente aos servicos publicos como eletricidade, gás natural, água e esgoto. A tecnologia de comunicação é o elemento essencial para permitir a formação de redes em que mensagens de controle e dados de medição possam ser transmitidos. Neste trabalho demonstra-se que as redes de sensores e atuadores sem fio são candidatas viáveis e adequadas para implementar estas redes. Os principais algoritmos de roteamento para esta categoria de rede sem fios são investigados, a fim de verificar o seu desempenho quando aplicados às características das redes urbanas de comunicação, que geralmente são redes de grande escala formadas por centenas a milhares de dispositivos. Ainda, demostra-se que o roteamento geográfico �e uma das estratégias mais adequadas de roteamento para redes sem fio de grande escala, devido às suas características de baixa sobrecarga e alta escalabilidade. Estes algoritmos geralmente combinam um encaminhamento geográfico greedy com um mecanismo de recuperação para solucionar o problema dos mínimos locais, sendo o roteamento por faces a solução mais empregada na literatura como método de recuperação. No entanto, o número médio de saltos nos caminhos produzidos pelo roteamento por faces pode ser muito maior do que o caminho topológico ótimo na maioria dos cenários reais. Neste trabalho propõe-se um procedimento intermediário entre o encaminhamento geográfico greedy e o modo de recuperação, a fim de melhorar a eficiência em número de saltos sem gerar sobrecarga de mensagens de controle. Este procedimento explora as rotas topológicas ótimas para as estações base como um recurso adicional para encontrar rotas melhores para outros nós do que as geradas pelo roteamento por faces. Demonstra-se ainda através de simulações que a abordagem híbrida proposta melhora significativamente o desempenho do encaminhamento de pacotes quando aplicada a algoritmos greedy combinados com roteamento por faces. Ademais, os resultados experimentais obtidos através da planta teste comprovam que os procedimentos de manutenção propostos são capazes de evitar flutuações na infra-estrutura de rede, oferecendo rotas robustas para o encaminhamento de pacotes em redes de grande escala.
4

Zásady pro provádění řížených protlaků pod komunikacemi / Principles for the implementation of controlled pressures under roads

Komoň, Richard Unknown Date (has links)
Goal of the diploma thesis is to explain what does the term of controlled horizontal drilling mean and where it can be performed. Furthermore, it wants to show what to pay attention to during designing as well as during the actual pilot drill. Additionally, to show that pilot drill cannot be performed based on the project in all scenarios. Theoretical part of the thesis explains how the technology works and which auxiliaries are necessary to successfully perform controlled pressure. This technology is explained step by step in the practical part of the thesis to show how to proceed during the realization of controlled pressure.
5

Návrh sekundárního městského kolektoru s důrazem na ochranu před průnikem podzemní vody / Design of the secondary city utility tunnel with an emphasis on protection against ingress of groundwater

Vrána, Tomáš January 2015 (has links)
In the first part, the master’s thesis deals with the history of utility tunnels, methods of construction processes and materials from which they are built. It also mentions methods and materials which protect against the effects of groundwater. The thesis is mainly dedicated to the design and structural design of the secondary utility tunnel lining with an emphasis on protection against ingress of groundwater. The mathematical model was created in Plaxis 2DAE software.
6

Obytný soubor Nový Žižkov - stavebně technologický projekt / Residential complex Nový Žižkov - construction technological project

Gabriel, Jan January 2019 (has links)
The subject of this diploma thesis is the elaboration of a construction technological project for the construction of a residential complex Nový Žižkov in Poděbrady, where I will focus on the technological stage of the gross building of the main building SO-01 apartment building – section BI+BII (56 dwelling units). The supporting system of the building is composed of a combination of monolithic reinforced concrete structures and ceramic blocks. The foundation of a residential building is designed as a reinforced concrete basin with reinforcing ribs. The diploma thesis contains a text and attachment part.

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