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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.
21

Performance Analysis of AODV, DSR and OLSR in MANET / Resultatanalys av AODV, DSR och OLSR i MANET

Ali, Sajjad, Ali, Asad January 2010 (has links)
A mobile ad hoc network (MANET) consists of mobile wireless nodes. The communication between these mobile nodes is carried out without any centralized control. MANET is a self organized and self configurable network where the mobile nodes move arbitrarily. The mobile nodes can receive and forward packets as a router. Routing is a critical issue in MANET and hence the focus of this thesis along with the performance analysis of routing protocols. We compared three routing protocols i.e. AODV, DSR and OLSR. Our simulation tool will be OPNET modeler. The performance of these routing protocols is analyzed by three metrics: delay, network load and throughput. All the three routing protocols are explained in a deep way with metrics. The comparison analysis will be carrying out about these protocols and in the last the conclusion will be presented, that which routing protocol is the best one for mobile ad hoc networks. / In all the three scenarios of small, large and very large networks OLSR gives considerably less delay and high throughput as compared to AODV and DSR. OLSR outperforms AODV and DSR with prominent difference in delay and throughput. While the AODV puts low load on the network in large and very large networks. OLSR outperforms in our study, but it is not necessary that OLSR always perform better in all the networks, its performance may vary by varying the network. / sajj_ali2003@yahoo.com, asad322@gmail.com
22

Ad-hoc Routing in Low Bandwidth Environments

Berg, Emil January 2016 (has links)
AODV (Ad hoc On-demand Distance Vector routing), DSDV (Destination-Sequenced Distance-Vector routing), DSR (Dynamic Source Routing), and OLSR (Optimized Link State Routing protocol) are protocols used for routing management in ad-hoc networks. In a specific sensor data network application, nodes need information about the network topology, i.e. the network nodes and the connections between them. OLSR provides nodes with this information, while the three other protocols do not. This thesis investigates how OLSR compares to AODV, DSDV,and DSR in a low bandwidth network scenario. Two cases were analyzed: One where AODV, DSDV, and DSR distribute topology information in the application layer and one where they do not. The sensor data application was not finished when this thesis project started. Instead, a simplified traffic model of the application was used. In addition to a protocol comparison, this thesis investigates if traffic generated from the model results in high rates of packet loss, assuming low bandwidth conditions. The ns-3 network simulator was used for these investigations. This thesis shows that AODV outperforms the three other protocols regardless of whether AODV, DSDV, and DSR distribute topology information in the application layer or not. Furthermore, it is shown that running the traffic model in the low bandwidth environment is not possible without high rates of packet loss.
23

A study of AODV and DSR protocols : A meta-analysis of AODV and DSR protocols

Maalouf, George January 2016 (has links)
There is a big number of people dying every year from car accidents and not solving this problem is a big issue. Communication protocols have been created in mobile ad-hoc network (MANET) to be able to solve this issue. AODV and DSR are two protocols that are used in this communication. The fact that there is mobile nodes makes it hard to keep track of the efficiency of this communication. This study has for objective giving a better understanding as to which protocol performs better and answering four important questions to know to be able to evaluate what protocol is better according to those parameters or criteria. The implemented method to solve this problem is through a meta-analysis and this meta-analysis is done through a qualitative research, literature review for critical literature reading and data collection to select the appropriate studies and exclud- ing the irrelevant studies based on other criteria. The evaluation of these param- eters are based on others’ work and reading the work from critical eyes. This study compares AODV and DSR from the criteria that are chosen. The study has a critical analysis of the results collected through the different papers show that AODV has outperformed DSR in most of the cases and answering the proposed questions in the study. Finally concluding that AODV is more effective in the case of high congestion compared to DSR but making a bit hard to have a clear cut answer when it comes to the criteria but AODV performed better in all the cases in high congestion.
24

Optimización probabilística de portafolios de tecnología convencional e inteligente para el diseño robusto de una subestación primaria de distribución

Soudre Donoso, Michel Gabriel January 2016 (has links)
Ingeniero Civil Eléctrico / El diseño de las subestaciones primarias de distribución se realiza actualmente de acuerdo al criterio determinístico de seguridad denominado N-1, el cual se basa en la salida intempestiva de uno de los transformadores de la subestación debido a un evento de falla. Sin embargo, este criterio no contempla eventos más graves de carácter catastrófico y producido, por ejemplo, por algún desastre natural (tormentas, inundaciones, terremotos, etc.). Además, este criterio actualmente utilizado no contempla la contribución de capacidad de tecnologías inteligentes, en específico, la que dota a la demanda la capacidad de participación activa (Demand Side Response o DSR) en los sistemas eléctricos. En esta memoria se propone un modelo probabilístico para el diseño robusto y eficiente de una subestación primaria de distribución que contempla el uso de transformadores y cables a subestaciones vecinas, como también el uso de DSR y generación distribuida de respaldo. El modelo determina la proporción óptima entre la capacidad de los transformadores, el número de cables a subestaciones vecinas, el monto DSR a contratar y la capacidad de la generación de respaldo. La optimización se realiza en base a una enumeración completa de los estados de la subestación, según la disponibilidad o indisponibilidad de cada elemento, y utilizando la demanda de un año según datos de una subestación real ubicada en el Reino Unido. La función objetivo incluye el valor de inversión y utilización de cada equipo como también el costo esperado de la energía no suministrada. Además, se incorpora a la optimización una restricción de la medida de riesgo CVaR(Conditional Value at Risk), la cual restringe la exposición al riesgo frente a eventos catastróficos, de baja probabilidad y alto impacto (HILP, High Impact Low Probability Events). Con el modelo probabilístico se estudian las distintas soluciones de diseño determinadas frente a distintos tipos de eventos catastróficos que pueden llegar a afectar a transformadores y equipos DSR, como falla de causa común debido a inundaciones y condiciones climáticas extremas. Del análisis se puede concluir que los equipos DSR son capaces de desplazar capacidad de transformación con respecto a la capacidad de diseño según el criterio N-1, y también, disminuyen la exposición al riesgo de eventos catastróficos como también los costos de capital de la subestación. Además, se deduce que la diversificación en la inversión de varios activos y tecnologías de red (transformadores, cables de transferencia y equipos DSR) producen una reducción de la exposición a altos niveles de energía no suministrada y también una disminución en los costos totales (capex, opex y energía no suministrada). Este trabajo busca determinar el aporte de la demanda en términos de su capacidad para desplazar potencia firme de unidades de transformación y representa un avance hacia la incorporación de equipos DSR en las futuras normas de distribución.
25

Směrovací protokoly v sítích s volnou topologií / Routing protocols in scale-free topology networks

Mahdal, Ondřej January 2008 (has links)
This master's thesis (further only MT) deal with problems of scale-free topology networks with a view to technology MANET (Mobile Ad hoc network) or more precisely Motorola MESH. Further studies routing technique and quality of services (QoS) in these networks. Theoretic part of MT in introduction shortly characterizes properties and kind of Ad hoc networks, next part is dedicated to technology Motorola MESH and shows practical usage of this technology. Analysis of problems quality of services and optimalization QoS in MANET is content third parts of MT. Fourth part specifies division of routing protocols, analysis of routing in MANET and characteristics routing protocols OLSR, AODV, DSR and TORA. In practical fifth part of MT are in introduction simulated simple MANET and mesh networks and further is created model of MANET network, into the model are implemented accessible routing protocols in simulation program OPNET Modeler and on the basis of simulation these protocols or more precisely output statisticians of simulation are protocols compared from several aspects and suitability for transmission of multimedia data (voice, video).
26

Control Applications and Economic Evaluations of Distributed Series Reactors in Unbalanced Electrical Transmission Systems

Omran, Shaimaa AbdAlla Ezz Ibrahim 07 May 2015 (has links)
An important issue in today's power system is the need to analyse and determine the adequacy of transmission capacity. There is a need for approaches to increase transmission system capacity without construction of new transmission facilities, all while assuring secure operation of the grid. New technologies can enhance efficiency and reliability, increase capacity utilization, enable more rapid response to contingencies, and increase flexibility in controlling power flows on transmission lines. Distributed Series Reactor (DSR) control is a new smart grid technology that can be applied to control flows in the transmission system. DSRs can be used to balance phase flows in a single line as well as to control the distribution of flow in parallel flow paths. This dissertation investigates the Design of Distributed Series Reactors (DSRs) on transmission lines and provide guidelines and considerations for their implementation in bulk power system transmission networks to control power flow to: increase the exisiting transmission capacity utilization, alleviate overloads due to load growth and contingencies, and mitigate the effects of unbalanced voltages, unbalanced transmission line impedances and unbalanced loads by balancing flows in the phases of an unbalanced line. This dissertation provides several DSR System Design aspects; for a single line by performing an experiment for EHV and high voltage three parallel transmission lines, and for lines within the boundaries of a power system by deployment of DSRs over the IEEE 39 bus system that is modified and modelled as a 3-phase unbalanced transmission model with 345 kV lines that accounts for tower geometry and as a balanced, 3-phase model that is derived from the unbalanced, 3-phase model, and finally for lines within a control area and a set of tie lines among control areas by deployment of DSRs over a real system control area and the tie lines connecting this area to other power pool areas. For all experiments and simulations in this dissertation lines are modelled as 3-phase lines. The DSR system design for Unbalanced vs. Balanced 3-phase systems (Unbalanced immittance, Unbalanced load) are examined. Also the Distributed vs. Lumped models for 3-phase systems are tested. Comparison between DSR system design and transposition for voltage balancing was performed. The effect of bundling the conductors for DSR system design was investiagted. In this dissertation an economic evaluation of DSR System Design for parallel lines and for the IEEE 39 bus three-phase unbalanced line model for N-1 criterion contingency with load growth is performed. The economic evaluation performed for the DSR system design of a power system versus new transmission line construction showed that DSRs can be cost effective in managing load increases from year to a year, and thus avoid larger investments in new line construction until load expectations are proven to be true. Thus, a major value of DSRs is handling load growth in the short term, delaying larger investments. Although many aspects of DSR control implementation have yet to be explored, this work has demonstrated the fundamental concept is sound and the economics are compelling. / Ph. D.
27

Control of Power Flow in Transmission Lines using Distributed Series Reactors

Nazir, Mohammad Nawaf 19 June 2015 (has links)
Distributed Series Reactors (DSRs) can be used to control power flow to more fully utilize the capacity of a transmission network, delaying investment in new transmission lines. In this study the IEEE 39 bus standard test system is modified to a 3-phase, unbalanced model consisting of 230 kV, 345 kV and 500 kV lines, where lines of different voltage run in parallel. This model is used to study load growth and the effect of adding DSRs to alleviate resulting overloads, and in particular to alleviate overloads on lines of different voltage running in parallel. The economic benefit of adding DSRs to the network is compared to the addition of new transmission lines in the network. In the second part of the work, the effect of unsymmetrical operation of DSRs on a single transmission line is studied and compared to the symmetrical operation of DSRs. It is found that the unsymmetrical operation of DSRs is more economical. Finally the unsymmetrical operation of DSRs to reduce voltage imbalance in the network is considered. / Master of Science
28

Influence of Aging on Foamed Warm Mix Asphalt

Akinbowale, Sunday Oyebisi 15 September 2014 (has links)
No description available.
29

Aging Characterization of Foamed Warm Mix Asphalt

Arefin, Mir Shahnewaz 14 September 2015 (has links)
No description available.
30

Análise, design e inovação de modelos de negócios para servitização / Analysis, design and innovation of business models for servitization.

Costa, Renato Machado 13 June 2017 (has links)
Empresas de manufatura tradicionalmente concentram os seus esforços em concepção, desenvolvimento, fabricação e comercialização de produtos físicos. No entanto, alguns fabricantes têm alterado suas estratégias de negócio, complementando a venda de produtos com o fornecimento de serviços, incorporando conhecimentos e atividades associados ao seu uso, e gerando maior percepção de valor por parte dos seus clientes. Com isso, a competição estratégica por meio de serviços tem se tornado uma marca distintiva das empresas de manufatura inovadoras, proporcionando à empresa um meio robusto para proteger o seu mercado dos concorrentes. Assim, observa-se um interesse crescente em pesquisas sobre o papel dos serviços para sustentar a competitividade da indústria. Abordagens orientadas a serviço, que incorporam esta mudança de foco do negócio, da oferta de produtos isolados para soluções integradas, têm sido tratadas na comunidade acadêmica como servitização, e tipicamente acarretam inovações no modelo de negócios (MN) da empresa. O objetivo deste trabalho é investigar como as empresas podem promover inovações em seus MNs para suportar suas estratégias de servitização, e propor um conjunto de artefatos para apoiá-las na implantação destas estratégias, a partir do seguinte problema de pesquisa: \"Como inovar o MN de uma empresa que adota a estratégia de servitização?\", que se desdobra nas seguintes questões: (i) quais são os principais fatores motivadores para uma empresa adotar a estratégia de servitização?; (ii) como representar o MN de uma empresa incorporando a lógica dominante de serviço, mais adequada para servitização?; (iii) como inovar o MN de uma empresa para implantar sua estratégia de servitização?; e (iv) como aplicar os artefatos propostos para apoiar a implantação da estratégia de servitização em uma empresa? Realiza-se uma pesquisa de natureza exploratória e prescritiva, baseada no método design scienceresearche amparada por uma revisão sistemática da literatura sobre os temas correlatos, visando propor artefatos em resposta às questões colocadas. A demonstração de um dos artefatos propostos é feita com suporte de um estudo de caso em uma empresa multinacional, fabricante de equipamentos médicos, seguida por uma avaliação empírica desta demonstração, suportada pelo método thinkingaloud. A partir das quatro questões de pesquisa, são obtidos os seguintes resultados: (i) identificação, análise e categorização dos principais fatores motivadores para adoção da servitização; (ii) proposição de uma arquitetura de MN incorporando a lógica dominante de serviço, para facilitar o estudo da servitização; (iii) proposição de um processo de inovação do MN da empresa, para implantar a servitização. e (iv) demonstração e avaliação da arquitetura proposta de MN para servitização. A pesquisa oferece contribuições à literatura de MN e servitização, e aos gestores de empresas, propondo os artefatos canvas do modelo de negócios para servitização (CMNS) e o processo IPIDI para inovação do MN para servitização, além de contribuições metodológicas relativas a design scienceresearch e thinking aloud. / Manufacturing companies traditionally are focused on designing, developing, manufacturing and marketing physical products. However, some manufacturers are changing their business strategies, complementing the sale of products by providing services, adding knowledge and activities associated with their use, and creating a higher perception of value by their customers.Strategic competition through service delivery has become a hallmark of the innovative manufacturing companies, providing the companies with a robust means to protect their market from competitors. Thus, there is a growing interest in researching the role of services in sustaining the competitiveness of manufacturing industry.Service-oriented approaches, which incorporate this shift in business\' focus from offering isolated products, to proposing integrated solutions, have been addressed in the literature as servitization, and typically entail innovations in the company\'s business model (BM). The goal of this research is investigating how companies can promote transformations in their BMs to support their servitization strategies, and proposing a set of artifacts to support them in the implementation of these strategies, since the following research problem: \"How to innovate the BM of a company which adopts the servitization strategy? \", which unfolds in the following questions: (i) what are the main motivating factors for a company to adopt the servitization strategy?; (ii) how to represent the BM of a company incorporating the service-dominant logic, more suitable for servitization?; (iii) how to innovate a company\'s BM to implement its servitization strategy ?; and (iv) how to apply the proposed artifacts to support the implementation of the servitization strategy in a company? An exploratory and prescriptive research is carried out, based on the design science research methodology, and supported by a systematic literature review on the related subjects, aiming at proposing artifacts in response to the questions posed. The demonstration of the proposed artifacts is done by means of a case study in a multinational company, which manufactures medical devices, followed by an assessment of this demonstration, supported by the thinking aloud method. From the four research questions, the following results are obtained: (i) identification, analysis and categorization of the main motivating factors for servitization adoption; (ii) proposing a BM architecture according to the service-dominant logic, to help the servitization study; (iii) proposing an innovation process for the company\'s BM, to implement the servitization; and (iv) demonstration and assessment of the proposed BM architecture for servitization. The research offers contributions to the literature of BM and servitization, and to practitioners, proposing the artifacts business model canvas for servitization (BMCS) and the IPIDI process for innovation of BM for servitization, besides some methodological contributions related to design science research and thinking aloud.

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