Computer networks can be classified into two broad categories: wired networks and wireless networks, according to the hardware and software technologies used to interconnect the individual devices. Wired interconnection networks are hardware fabrics supporting communications between individual processors in highperformance computing systems (e.g., multi-computer systems and cluster systems). On the other hand, due to the rapid development of wireless technologies, wireless networks have emerged and become an indispensable part for people's lives. The integration of different wireless technologies is an effective approach to accommodate the increasing demand of the users to communicate with each other and access the Internet. This thesis aims to investigate the performance of wired interconnection networks and integrated wireless networks under the realistic working conditions. Traffic patterns have a significant impact on network performance. A number of recent measurement studies have convincingly demonstrated that the traffic generated by many real-world applications in communication networks exhibits bursty arrival nature and the message destinations are non-uniformly distributed. Analytical models for the performance evaluation of wired interconnection networks and integrated wireless networks have been widely reported. However, most of these models are developed under the simplified assumption of non-bursty Poisson process with uniformly distributed message destinations. To fill this gap, this thesis first presents an analytical model to investigate the performance of wired interconnection networks in multi-computer systems. Secondly, the analytical models for wired interconnection networks in multi-cluster systems are developed. Finally, this thesis proposes analytical models to evaluate the end-to-end delay and throughput of integrated wireless local area networks and wireless mesh networks. These models are derived when the networks are subject to bursty traffic with non-uniformly distributed message destinations which can capture the burstiness of real-world network traffic in the both temporal domain and spatial domain. Extensive simulation experiments are conducted to validate the accuracy of the analytical models. The models are then used as practical and cost-effective tools to investigate the performance of heterogeneous wired or wireless networks under the traffic patterns exhibited by real-world applications.

Vertical-axis wind turbines (VAWTs) have with time been outrivaled by the today more common and economically feasible horizontal-axis wind turbines (HAWTs). However, VAWTs have several advantages which still make them interesting, for example, the VAWTs can have the drive train at ground level and it has been argued that they have lower noise emission. Other proposed advantages are suitability for both up-scaling and floating offshore platforms. The work within this thesis is made in collaboration between Halmstad University and Uppsala University. A 200-kW semi-guy-wired VAWT H-rotor, owned by Uppsala University but situated in Falkenberg close to Halmstad, has been the main subject of the research although most results can be generalized to suit a typical H-rotor. This thesis has three main topics regarding VAWTs: (1) how the wind energy extraction is influenced by turbulence, (2) aerodynamical noise generation and (3) eigenfrequencies of the semi-guy-wired tower. The influence from turbulence on the wind energy extraction is studied by evaluating logged operational data and examining how the power curve and the tip-speed ratio for maximum Cp is impacted by turbulence. The work has showed that the T1-turbine has a good ability to extract wind energy at turbulent conditions, indicating an advantage in energy extraction at turbulent sites for VAWTs compared to HAWTs.The noise characteristics are studied experimentally, and models of the two most likely aerodynamic noise mechanisms are applied. Here, inflow-turbulence noise is deemed as the prevailing noise source rather than turbulent-boundary-layer trailing-edge noise (TBL-TE) which is the most important noise mechanism for HAWTs. The overall noise emission has also been measured and proven low compared to similar sized HAWTs. The eigenfrequencies of a semi-guy-wired tower are also studied. Analytical expressions describing the first-mode eigenfrequency of both tower and guy wire has been derived and verified by experiments and simulations.

Ces travaux de thèse portent sur la détection de défauts d'isolement dans des lignes de transmission de grandes longueurs. Il s'agit de détecter des défauts non francs liés à l'isolant entre les conducteurs d'un câble de grande longueur qui sont représentés par le paramètre de conductance de fuite. Détecter ces défauts, signes d'un possible futur court-circuit, est un enjeu important mais nécessite une méthode non invasive. Par exemple, dans le cas des câbles de signalisation SNCF, il s'agit de développer une méthode de diagnostic de très faibles conductances de fuite dans les câbles de signalisation le long des voies ferrées compatible avec la circulation des trains. Il faut savoir estimer, à partir de mesures en un seul point du câble, de fortes résistances distribuées sur plusieurs centaines de mètres sans perturber la bande de fréquences du continu à 40 kHz, réservée aux signaux de service. En effet, les câbles de signalisation de la SNCF qui nous intéressent ont une longueur moyenne de 1500 m et sont utilisés dans la bande de fréquence 0-40 kHz. Nous proposons donc une méthode fréquentielle permettant d'estimer de faibles défauts à moyenne fréquence dans des lignes de transmission uniformes avec pertes. Elle repose sur deux idées principales : une analyse fine des effets conjoints de la dissipation et de la dispersion et une méthode de comparaison de deux lignes ayant les mêmes caractéristiques et ne différant que du paramètre de conductance de fuite. Cette méthode de comparaison a été généralisée dans le cas de lignes multiconducteurs en adoptant une démarche statistique.\\Cette thèse a apporté de nouveaux résultats : des formules d'estimation de pertes découlant de l'analyse fine d'une part des effets conjoints de la dissipation et de la dispersion et d'autre part de la méthode de comparaison de deux lignes. Des simulations numériques ont été faites dans les deux cas afin de valider la méthode fréquentielle proposée. Des expériences ont été réalisées afin de valider l'analyse statistique développée dans le cas de lignes multiconducteurs. / This thesis work focuses on the detection of insulation faults in very long transmission lines. This is detecting soft defects related to the insulation between the conductors of a long cable which are represented by the leakage conductance parameter. Detect these faults, signs of a possible future short-circuit, is an important issue but requires a noninvasive method. For example, in the case of railway signaling cables, it is to develop a method of diagnosis of very low leakage conductances in signaling cables along railways compatible with the movement of trains. Be aware estimate from measurements in one point of the cable, strong resistance distributed over several hundred meters without disturbing the continuous frequency range to 40 kHz, reserved for service signals. Indeed, the signal cables from the train that interest us have an average length 1500 m and are used in the frequency band 0-40 kHz.We propose so a frequency method for estimating low defects to medium frequency in uniform transmission lines with losses. It is based on two main ideas : a detailed analysis of joint effects of dissipation and dispersion and a method of comparing two lines having the same characteristics and differing only leak conductance parameter. This method of comparison was widespread in the case of multiconductor lines by adopting a statistical approach.This thesis has brought new results : losses estimation formulas resulting from the detailed analysis of a share of joint effects of dissipation and dispersion and also the method of comparing two lines. Numerical simulations were made in both cases to validate the proposed frequency method. Experiments were performed to validate the statistical analysis in the case of multiconductor lines.

O presente trabalho tem como foco principal estudar o Museu Casa da Xilogravura da cidade do Campos do Jordão. Uma questão foi desenvolvida a partir da colaboração da Arte/educação nas ações educativas do Museu: Quais as possibilidades educativas do Museu Casa da Xilogravura para a formação inicial de professores de Arte Visuais? Resgataram-se informações sobre o Festival de Inverno de Campos do Jordão, como medida para reestabelecer relações com as ações contemporâneas sugeridas nesta pesquisa: a ligação da formação de professores em Artes Visuais com a cidade de Campos do Jordão, como também com suas cercanias. Outros assuntos pertinentes ao trabalho foram desenvolvidos como, por exemplo, os estudos sobre a abordagem do ensino superior, elaborados pelos professores Paulo Freire e Thierry De Duve, que embasaram a discussão sobre a formação inicial de professores de artes. Breve estudo sobre a legislação no ensino da arte foi escrito para reflexões sobre as políticas públicas no Ensino Superior. Um recorte de estudo sobre a importância do trabalho educativo dos museus como formação de um conceito, bem como um recorte histórico do Educativo dos primeiros museus paulistas, também consta deste trabalho. Foram desenvolvidos estudos sobre Curadoria Educativa e museu, e acervos digitais, devido às suas relações com a proposta da tese. Foi feito um levantamento de trabalhos com bases no Projeto Observatório da Formação de Professores que versavam a respeito da Educação em Museus no âmbito da graduação, que por sinal notou-se uma quantia bem pequena na pesquisa. Um pequeno histórico a respeito da formação do acervo do Museu Casa da Xilogravura foi realizado, por meio de informação bibliográfica, documental e depoimentos orais. Foram atualizados os dados quantitativos referentes às visitações presenciais dos estudantes de Ensino Básico ao Museu, assim como a maneira pela qual o visitante espontâneo acessa as informações sobre a Instituição. Um aprofundamento a respeito da Leitura da Obra de Arte, no âmbito da Abordagem Triangular do Ensino da Arte de Ana Mae Barbosa, e o Desenvolvimento Estético foi pensado sob à luz dos conceitos de quatro pesquisadores: Edmund B. Feldman, Robert W. Ott, Michael J. Parsons e Abigail Housen. Construiu-se um modelo autônomo, porém com bases nessas teorias, que levou a uma proposta de Material de Apoio ao professor em Artes Visuais, a ser oferecida às Instituições de Ensino Superior das regiões do Vale do Paraíba, sul de Minas Gerais e Rio de Janeiro. Este material apresenta a obra de Lasar Segall, chamada \"Casal no Mangue\", de 1929, xilogravura impressa em papel, que faz parte do acervo do Museu Casa da Xilogravura. / The current dissertation focuses mainly on studying the Woodcutting House Museum in the town of Campos do Jordão. A question was raised regarding the Arts/Education cooperation related to the teaching activities of this museum: \"What are the educational possibilities of the Casa da Xilogravura Museum for the initial training of Visual Art teachers?\". Information was gathered on the Festival de Inverno de Campos do Jordão (Winter Festival of Campos do Jordão) as parameters to reestablishing the relationships with current actions in which we suggest in this research a link between the visual arts teacher training and the town of Campos do Jordão, as well as its surroundings. Other pertinent issues were also considered, such as the approach to advanced studies elaborated by the professors Paulo Freire and Thierry De Duve as the basis for the discussion about the initial training of arts teachers. Brief study on legislation in the teaching of art was written for reflections on public policies in Higher Education. This paper comprises a cross section of the importance of the teaching work of the museums as basis of a concept, as well as a historic cross section on the teaching aspect of the first museums of the State of São Paulo. Studies on Educational Curatorship and Museum and digital collections were developed based on the relations we suggest on this thesis. A survey was carried out on the basis of the Observatory Project for Teacher Training, which dealt with the Education in Museums within the scope of graduation, which, by the way, was a very small amount in the research. A brief record on the development of the collection belonging to the Casa da Xilogravura Museum was made using bibliographic, documental and oral statement information; and we updated the quantitative data regarding personal visits of Fundamental School students to the Museum, as well as how the spontaneous visitor accesses the existing information on it. The study thoroughly contemplates the reading of the works-of-arts within the scope of the Triangular Approach of Arts Teaching by Ana Mae Barbosa; also, the Aesthetic Development was regarded in the light of the concepts of four researchers: Edmund B. Feldman, Robert W. Ott, Michael J. Parsons and Abigail Housen. We built an autonomous model based on these theories, which led us to propose Support Materials to the Visual Arts teacher which should be offered to the Colleges of the regions of Vale do Paraíba, South of Minas Gerais and South of Rio de Janeiro. This material presents the work of Lasar Segall, called \"Couple in the Mangue\", 1929, woodcut printed on paper, which is part of the collection of the Casa da Xilogravura Museum.

O presente trabalho tem como foco principal estudar o Museu Casa da Xilogravura da cidade do Campos do Jordão. Uma questão foi desenvolvida a partir da colaboração da Arte/educação nas ações educativas do Museu: Quais as possibilidades educativas do Museu Casa da Xilogravura para a formação inicial de professores de Arte Visuais? Resgataram-se informações sobre o Festival de Inverno de Campos do Jordão, como medida para reestabelecer relações com as ações contemporâneas sugeridas nesta pesquisa: a ligação da formação de professores em Artes Visuais com a cidade de Campos do Jordão, como também com suas cercanias. Outros assuntos pertinentes ao trabalho foram desenvolvidos como, por exemplo, os estudos sobre a abordagem do ensino superior, elaborados pelos professores Paulo Freire e Thierry De Duve, que embasaram a discussão sobre a formação inicial de professores de artes. Breve estudo sobre a legislação no ensino da arte foi escrito para reflexões sobre as políticas públicas no Ensino Superior. Um recorte de estudo sobre a importância do trabalho educativo dos museus como formação de um conceito, bem como um recorte histórico do Educativo dos primeiros museus paulistas, também consta deste trabalho. Foram desenvolvidos estudos sobre Curadoria Educativa e museu, e acervos digitais, devido às suas relações com a proposta da tese. Foi feito um levantamento de trabalhos com bases no Projeto Observatório da Formação de Professores que versavam a respeito da Educação em Museus no âmbito da graduação, que por sinal notou-se uma quantia bem pequena na pesquisa. Um pequeno histórico a respeito da formação do acervo do Museu Casa da Xilogravura foi realizado, por meio de informação bibliográfica, documental e depoimentos orais. Foram atualizados os dados quantitativos referentes às visitações presenciais dos estudantes de Ensino Básico ao Museu, assim como a maneira pela qual o visitante espontâneo acessa as informações sobre a Instituição. Um aprofundamento a respeito da Leitura da Obra de Arte, no âmbito da Abordagem Triangular do Ensino da Arte de Ana Mae Barbosa, e o Desenvolvimento Estético foi pensado sob à luz dos conceitos de quatro pesquisadores: Edmund B. Feldman, Robert W. Ott, Michael J. Parsons e Abigail Housen. Construiu-se um modelo autônomo, porém com bases nessas teorias, que levou a uma proposta de Material de Apoio ao professor em Artes Visuais, a ser oferecida às Instituições de Ensino Superior das regiões do Vale do Paraíba, sul de Minas Gerais e Rio de Janeiro. Este material apresenta a obra de Lasar Segall, chamada \"Casal no Mangue\", de 1929, xilogravura impressa em papel, que faz parte do acervo do Museu Casa da Xilogravura. / The current dissertation focuses mainly on studying the Woodcutting House Museum in the town of Campos do Jordão. A question was raised regarding the Arts/Education cooperation related to the teaching activities of this museum: \"What are the educational possibilities of the Casa da Xilogravura Museum for the initial training of Visual Art teachers?\". Information was gathered on the Festival de Inverno de Campos do Jordão (Winter Festival of Campos do Jordão) as parameters to reestablishing the relationships with current actions in which we suggest in this research a link between the visual arts teacher training and the town of Campos do Jordão, as well as its surroundings. Other pertinent issues were also considered, such as the approach to advanced studies elaborated by the professors Paulo Freire and Thierry De Duve as the basis for the discussion about the initial training of arts teachers. Brief study on legislation in the teaching of art was written for reflections on public policies in Higher Education. This paper comprises a cross section of the importance of the teaching work of the museums as basis of a concept, as well as a historic cross section on the teaching aspect of the first museums of the State of São Paulo. Studies on Educational Curatorship and Museum and digital collections were developed based on the relations we suggest on this thesis. A survey was carried out on the basis of the Observatory Project for Teacher Training, which dealt with the Education in Museums within the scope of graduation, which, by the way, was a very small amount in the research. A brief record on the development of the collection belonging to the Casa da Xilogravura Museum was made using bibliographic, documental and oral statement information; and we updated the quantitative data regarding personal visits of Fundamental School students to the Museum, as well as how the spontaneous visitor accesses the existing information on it. The study thoroughly contemplates the reading of the works-of-arts within the scope of the Triangular Approach of Arts Teaching by Ana Mae Barbosa; also, the Aesthetic Development was regarded in the light of the concepts of four researchers: Edmund B. Feldman, Robert W. Ott, Michael J. Parsons and Abigail Housen. We built an autonomous model based on these theories, which led us to propose Support Materials to the Visual Arts teacher which should be offered to the Colleges of the regions of Vale do Paraíba, South of Minas Gerais and South of Rio de Janeiro. This material presents the work of Lasar Segall, called \"Couple in the Mangue\", 1929, woodcut printed on paper, which is part of the collection of the Casa da Xilogravura Museum.

This work deals with the study of Yagi-Uda antennas, followed by analysis and design of planar antenna with wired reflector. The first part focused on the analysis of the antenna and parameters. Another part of the continuing investigation of the optimum parameters for a given antenna followed by a design in Wi-Fi 5 GHz band. The antenna is simulated in CST Microwave Studio. The final part devoted the results achieved

Computer networks can be classified into two broad categories: wired networks and wireless networks, according to the hardware and software technologies used to interconnect the individual devices. Wired interconnection networks are hardware fabrics supporting communications between individual processors in highperformance computing systems (e.g., multi-computer systems and cluster systems). On the other hand, due to the rapid development of wireless technologies, wireless networks have emerged and become an indispensable part for people¿s lives. The integration of different wireless technologies is an effective approach to accommodate the increasing demand of the users to communicate with each other and access the Internet. This thesis aims to investigate the performance of wired interconnection networks and integrated wireless networks under the realistic working conditions. Traffic patterns have a significant impact on network performance. A number of recent measurement studies have convincingly demonstrated that the traffic generated by many real-world applications in communication networks exhibits bursty arrival nature and the message destinations are non-uniformly distributed. Analytical models for the performance evaluation of wired interconnection networks and integrated wireless networks have been widely reported. However, most of these models are developed under the simplified assumption of non-bursty Poisson process with uniformly distributed message destinations. To fill this gap, this thesis first presents an analytical model to investigate the performance of wired interconnection networks in multi-computer systems. Secondly, the analytical models for wired interconnection networks in multi-cluster systems are developed. Finally, this thesis proposes analytical models to evaluate the end-to-end delay and throughput of integrated wireless local area networks and wireless mesh networks. These models are derived when the networks are subject to bursty traffic with non-uniformly distributed message destinations which can capture the burstiness of real-world network traffic in the both temporal domain and spatial domain. Extensive simulation experiments are conducted to validate the accuracy of the analytical models. The models are then used as practical and cost-effective tools to investigate the performance of heterogeneous wired or wireless networks under the traffic patterns exhibited by real-world applications.

Group communication, security and 5G technology present a unique dimension of challenges and security remains crucial in the successful deployment of 5G technology across different industry. Group key management plays a vital role in secure group communication. This research work studies various group key management schemes for mobile wireless technology and then a new scheme is proposed and evaluated. The main architecture is analysed, while the components and their roles are established, trust and keying relationships are evaluated, as well as detailed functional requirements. A detailed description of the main protocols required within the scheme is also described. A numerical and simulation analysis is employed to assess the proposed scheme with regards to fulfilling the security requirement and performance requirements. The impact of group size variation, the impact of mobility rate variation are studied with regards to the average rekeying messages induced by each event and 1-affects-n phenomenon. The results obtained from the simulation experiments show that the proposed scheme outperformed other solutions with a minimal number of rekeying messages sent and less number of affected members on each event. The security requirements demonstrate that backward and forward secrecy is preserved and maintained during mobility between areas. Finally, the research work also proposes a 5G-enabled software-defined multicast network (5G-SDMNs), where software-defined networking (SDN) is exploited to dynamically manage multicast groups in 5G and mobile multicast environment. Also, mobile edge computing (MEC) is exploited to strengthen network control of 5G-SDMN. / National Open University of Nigeria

Le remplacement des systèmes de distribution d’énergie actuels dans les avions (pneumatiques, hydrauliques, mécaniques et électriques) par des systèmes 100% électriques est un enjeu majeur dans le cadre du projet de l’avion « plus électrique ». Le processus d’électrification de l’avion conduit à une augmentation de la puissance embarquée à bord des aéronefs, et par conséquent à une augmentation de la masse du réseau filaire. Afin de pallier à cette augmentation, un nouveau matériau composite possédant des propriétés électriques supérieures à celle du cuivre a été développé dans le but d’augmenter la capacité de courant admissible dans le conducteur à section constante. Ce travail de thèse présente le procédé d’élaboration du matériau composite cuivre-nanotubes de carbone développé ainsi que les techniques de caractérisation utilisées et les résultats associés. Différents paramètres tels que la qualité de la dispersion des renforts dans la matrice, le type de nanotubes de carbone utilisés (multi-parois vs mono-paroi), la nature de l’interface créée entre le cuivre et les renforts (mécanique vs chimique) ainsi que les techniques de mise en forme du matériau (pressage uni-axial à chaud, extrusion à chaud) et de post-traitements (recuit, laminage à chaud) ont été étudiés afin d’obtenir des propriétés physiques optimales. Il en résulte une augmentation des propriétés thermiques (+6,8% pour la conductivité thermique), mécaniques (+32% pour la dureté Vickers) et également électriques - pour la première fois observée- (+3,4 % pour la conductivité électrique) et ce en comparaison avec à une matrice de cuivre pur. / The substitution of the current energy chains in aircrafts (pneumatic, hydraulic, mechanical and electrical) by a 100% electrical chain is a major issue in the field of the “more electric” aircraft. The electrification process leads to an increase of the inboard power of aircrafts, and therefore to an increase of the wired network weight. To counterbalance this increase of mass, a new composite material with higher electrical properties that copper should be considered, in order to increase the current density in the conductor at constant cross section. Several parameters have been studied such as the quality of the carbon nanotubes dispersion, the type of CNTs used (single-walled vs. multi walled), the interface between the matrix and the reinforcements (mechanical vs. chemical), the shaping of material (uni-axial hot pressing, hot extrusion process) and the post treatments processes (heat treatment, hot lamination process). An enhancement of the thermal properties (+ 6.8% of thermal conductivity), the mechanical properties (+32% of Vickers hardness) and for the first time an increase of the electrical properties (+3.4 % for the electrical conductivity) have been observed in comparison with pure copper.

Authentication protocols are used for two parties to authenticate each other and build a secure channel over wired or wireless public channels. However, the present standards of authentication protocols are either insufficiently secure or inefficient for light weight devices. Therefore, we propose two authentication protocols for improving the security and user efficiency in wired and wireless environments, respectively. Traditionally, TLS/SSL is the standard of authentication and key exchange protocols in wired Internet. It is known that the security of TLS/SSL is not enough due to all sorts of client side attacks. To amend the client side security, multi-factor authentication is an effective solution. However, this solution brings about the issue of biometric privacy which raises public concern of revealing biometric data to an authentication server. Therefore, we propose a truly three factor authentication protocol, where the authentication server can verify their biometric data without the knowledge of users¡¦ templates and samples. In the major wireless technologies, extensible Authentication Protocol (EAP) is an authentication framework widely used in IEEE 802.11 WLANs. Authentication mechanisms built on EAP are called EAP methods. The requirements for EAP methods in WLANs authentication have been defined in RFC 4017. To achieve user efficiency and robust security, lightweight computation and forward secrecy, excluded in RFC 4017, are desired in WLAN authentication. However, all EAP methods and authentication protocols designed for WLANs so far do not satisfy all of the above properties. We will present a complete EAP method that utilizes stored secrets and passwords to verify users so that it can (1) meet the requirements of RFC 4017, (2) provide lightweight computation, and (3) allow for forward secrecy. In order to prove our proposed protocols completely, we apply two different models to examine their security properties: Bellare¡¦s model, a standard reduction based on computational model, that reduces the security properties to the computationally hard problems and the OFMC/AVISPA tool, a model checking approach based on formal model, that uses the concept of the search tree to systematically find the weaknesses of a protocol. Through adopting Bellare¡¦s model and OFMC/AVISPA tool, the security of our work is firmly established.