Distributed real-time databases can be used to support data sharing for applications in wireless ad-hoc networks. In such networks, topology changes frequently and partitions may be unpredictable and last for an unbounded period. In this thesis, the existing database replication protocol PRiDe is extended to handle such long-lasting partitions. The protocol uses optimistic and detached replication to provide predictable response times in unpredictable networks and forward conflict resolution to guarantee progress. The extension, pPRiDe, combines update and state transfer strategies. Update transfer for intra-partition communication can reduce bandwidth usage and ease conflict resolution. State transfer for inter partition conflicts removes dependency on a common state between partitions prior to the merge to apply update messages on. This makes the resource usage independent of the life span of partitions. This independence comes at the cost of global data stability guarantees and pPRiDe can thus only provide per partition guarantees. The protocol supports application specific conflict resolution routines for both state and update conflicts. A basic simulator for mobile ad-hoc networks has been developed to validate that pPRiDe provides eventual consistency. pPRiDe shows that a hybrid approach to change propagation strategy can be beneficial in networks where collaboration by data sharing within long lasting partitions and predictable resource usage is necessary. These types of systems already require the conflict management routines necessary for pPRiDe and can benefit from an existing protocol. In addition to pPRiDe and the simulator this thesis provides a flexible object database suitable for future works and an implementation of PRiDe on top of that database.

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.

The spread of wireless devices inspired the creation of a DEECo component model suitable for designing applications with immanent mobility and dynamic composition where the system architecture emerges at runtime. A great challenge in implementation of such a system is the underlying communication mechanism based on gossip protocol in order to achieve resilience and suitability for MANET networks. In this thesis we propose an optimization of the protocol exploiting infrastructure networks, but still preserving the gossip-like communication without a centralized element. The improvement is based on forming communication groups introduced at the design level. The experiments show a substantial decrease in the number of sent messages and a decrease in time of data delivery. The timing aspect of data delivery is further elaborated for MANET networks by implementing a pulling mechanism with significant improvement of the latency. Part of this thesis is dedicated to a formal specification of the system semantic to provide a precise rationale about its properties and laying the ground for further extensions and research. Powered by TCPDF (www.tcpdf.org)

Physical indoor wireless network testbeds as well as outdoor wireless testbeds have the potential to accelerate the pace of research in the field of wireless ad hoc and mesh networking. They form part of a critical chain of steps needed to develop and test ad hoc networking protocols from concept to eventual uptake by industry. Current research in this area makes use of simulations or mathematical models which oversimplify the physical and Medium Access Control layer. In Africa specifically, wireless mesh networking has the potential to make a substantial impact on the lack of telecommunications infrastructure across the continent. A combination of good theoretical analysis, indoor test facilities and rural testbeds forms a perfect suite to carry out meaningful research in the field. A 7x7 wireless grid of closely spaced computers was constructed, making use of highly attenuated 802.11 radios running in ad hoc mode. Modelling and analysis revealed that a suitably attenuated environment was created with variation in signal strength between node pairs following a Gaussian distribution. This emulates a real outdoor network with normal signal propagation issues such as multi-path fading and lack of Fresnel zone clearance. This testbed was then used to evaluate 3 popular MANET ad hoc routing protocols, namely AODV, DYMO and OLSR. OLSR was tested with the standard hysteresis routing metric as well as the ETX routing metric. OLSR showed the best performance in terms of average throughput and packet loss for a medium size (21 node) and large (49 node) mesh network, with the hysteresis routing metric performing best in large networks and ETX performing best in medium sized networks. DYMO also performed very well, considering its low routing overhead, exhibiting the least amount of delay in a large mesh network (49 nodes). The AODV protocol showed the weakest performance in the grid with close to 60% of possible link pairs achieving no route in a 49-node grid. However, it did present the least amount of routing overhead compared with other routing protocols. Finally, a medium-sized rural mesh network testbed consisting of 9 nodes was built in a mountainous area of about 15 square kilometers around an AIDS clinic using the OLSR routing protocol with ETX as the routing metric. The network provided a good service to the satellite-based Internet with throughput rates ranging between 300 kbps for 4 hops and 11000 kbps for 1 hop and an average throughput rate of 2324 kbps. To encourage fair sharing of Internet connectivity, features were installed to limit each user to 40 MB/month of free Internet traffic. A local web server offers cached pages of Wikipedia and Linux repositories to reduce the need for Internet access. VoIP services were also installed between clinic infrastructure to reduce the the need for making expensive GSM calls. It was shown that a mesh network of this size provides a very satisfactory level of broadband service for users accessing a satellite-based Internet facility as well as local VoIP services. / Dissertation (MEng)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / unrestricted

Unique élève d’Édouard Manet, Eva Gonzalès (1849-1883) est née dans un foyer bourgeois d’artistes et d’esthètes. Elle fréquente, dès sa plus tendre enfance, les milieux les plus sophistiqués des arts et des lettres grâce à son père, le romancier Emmanuel Gonzalès. Formée par le peintre académique Charles Chaplin, c’est finalement auprès du moderne Édouard Manet qu’Eva Gonzalès se tourne pour parfaire sa formation artistique. À son contact, et au contact des artistes impressionnistes qui l’entourent, l’œuvre de la jeune femme s’ouvre vers l’extérieur, en gardant toujours la figure de sa sœur Jeanne, son modèle privilégié. Eva Gonzalès épouse en 1879 un graveur talentueux et fantaisiste, Henri Guérard, ami de son maître Manet et des peintres-graveurs de la seconde moitié du XIXe siècle. Une complicité artistique naît entre les deux époux. Mais un paradoxe s’opère dans la carrière d’Eva Gonzalès. En dépit de ses toiles à la touche impressionniste, l’artiste préfère suivre la direction qu’elle juge la mieux adaptée à sa nature calme et docile, et rester en retrait de ce groupe. À l’instar de Manet, elle ne participe pas à leurs expositions, préférant diffuser son œuvre par la voie officielle du Salon. La bonne réception de ses toiles se partage donc entre les critiques des journaux conservateurs, qui appuient les choix du jury du Salon, et le soutien des défenseurs de la peinture moderne, elle qui est l’unique élève de Manet, leur chef de file. La visée de ce travail est donc d’étudier la vie et l’œuvre d’Eva Gonzalès en déchiffrant l’ensemble de ce réseau social qui s’est tissé autour de cette personnalité dans la seconde moitié du XIXe siècle. / As known as the only pupil of Édouard Manet, Eva Gonzalès (1849-1883) grew up in an upper middle class family of artists and aesthetes. Thanks to her father, the novelist Emmanuel Gonzalès, she became familiar with the most sophisticated Arts and Literature circles since her earliest childhood. Originally trained by the academic painter Charles Chaplin, it is finally towards the progressive Édouard Manet that Eva Gonzalès turned. Under the influence of the latter and of the impressionist artists who surrounded him, the work of the young woman reached a turning-point, through her depictions of natural sceneries, although keeping the figure of her sister Jeanne. In 1879, Eva Gonzalès married Henri Guérard, a talented and fanciful engraver, as well as a friend of her mentor, Manet. An artistic bond arose from their union. Nevertheless, as a paradox in the career of Eva Gonzalès, and in spite of her paintings largely inspired by the impressionist movement, the artist prefered to follow the direction which she considered as the most suitable for her calm nature. Following the example of Manet, she chose to not take part in their exhibitions, preferring to spread her work by the official way of the Salon. The appreciation of her paintings came thus from both sides: on one side from the critics of the conservative newspapers which supported the choices of the jury of the Salon, and on the other side from the defenders of modern painting who were seeing in her the only pupil of Manet, their leader. The aim of this work is to study Eva Gonzalès’ life and work by analysing this wide social network that surrounded this personality in the second half of the 19th century.

[EN] Vehicular Ad-hoc Networks (VANET) are a special type of networks where the nodes involved in the communication are vehicles. VANETs are created when several vehicles connect among themselves without the use of any infrastructure. In certain situations the absence of infrastructure is an advantage, but it also creates several challenges that should be overcome. One of the main problems related with the absence of infrastructure is the lack of a coordinator that can ensure a certain level of quality in order to enable the correct transmission of video and audio. Video transmission can be extremely useful in this type of networks as it can be used for videoconferencing of by traffic authorities to monitor the scene of an accident. In this thesis we focused on real time video transmission, providing solutions for both unicast and multicast environments. Specifically, we built a real-world testbed scenario and made a comparison with simulation results to validate the behavior of the simulation models. Using that testbed we implemented and improved DACME, an admission control module able to provide Quality of Service (QoS) to unicast video transmissions. DACME proved to be a valid solution to obtain a certain level of QoS in multi-hop environments. Concerning multicast video transmission, we developed and simulated several flooding schemes, focusing specifically on VANET environments. In this scope, the main contribution of this thesis is the Automatic Copies Distance Based (ACDB) flooding scheme. Thanks to the use of the perceived vehicular density, ACDB is a zeroconf scheme able to achieve good video quality in both urban and highway environments, being specially effective in highway environments. / [ES] Las redes vehiculares ad-hoc (VANET) son un tipo especial de redes en las que los nodos que participan de la comunicación son vehículos. Las VANETs se crean cuando diversos vehículos se conectan entre ellos sin el uso de ninguna infraestructura. En determinadas situaciones, la ausencia de infraestructura es una ventaja, pero también crea una gran cantidad de desafíos que se deben superar. Uno de los principales problemas relacionados con la ausencia de infraestructura, es la ausencia de un coordinador que pueda asegurar un determinado nivel de calidad, para poder asegurar la correcta transmisión de audio y vídeo. La transmisión de vídeo puede ser de extrema utilidad en este tipo de redes ya que puede ser empleada para videoconferencias o por las autoridades de tráfico para monitorizar el estado de un accidente. En esta tesis nos centramos en la transmisión de vídeo en tiempo real, proveyendo soluciones tanto para entornos unicast como multicast. En particular construimos un banco de pruebas real y comparamos los resultados obtenidos con resultados obtenidos en un entorno simulado para comprobar la fiabilidad de estos modelos. Usando el mismo banco de pruebas, implementamos y mejoramos DACME, un módulo de control de admisión capaz de proveer de calidad de servicio a transmisiones de vídeo unicast. DACME probó ser una solución válida para obtener ciertos niveles de calidad de servicio en entornos multisalto. En lo referente a la transmisión de vídeo multicast, desarrollamos y simulamos diversos esquemas de difusión diseñados específicamente para entornos VANET. En este campo, la principal contribución de esta tesis es el esquema de difusión "Automatic Copies Distance Based" (ACDB). Gracias al uso de la densidad vehicular percibida, ACDB es un esquema, que sin necesidad de configuración, permite alcanzar una buena calidad de vídeo tanto en entornos urbanos como en autopistas, siendo especialmente efectivo en este último entorno. / [CAT] Les xarxes vehiculars ad-hoc (VANET) son un tipus de xarxes especials a les que els diferents nodes que formen part d'una comunicació son vehicles. Les VANETs es formen quan diversos vehicles es connecten sense fer ús de cap infraestructura. A certes situacions l'absència d'una infraestructura suposa un avantatge, encara que també genera una gran quantitat de desafiaments que s'han de superar. U dels principals problemes relacionats amb l'absència d'infraestructura, és la manca d'un coordinador que puga garantir una correcta transmissió tant de video com d'àudio. La transmissió de video pot ser d'extrema utilitat a aquest tipus de xarxes, ja que es por emprar tant per a videoconferències com per part de les autoritats de trànsit per monitoritzar l'estat d'un accident. A aquesta tesi ens centrem en transmissió de video en temps real, proporcionant solucions tant a entorns unicast como a entorns multicast. Particularment, vam construir un banc de proves i obtinguérem resultats que comparàrem amb resultats obtinguts mitjançant simulació. D'aquesta manera validarem la fiabilitat dels resultats simulats. Fent ús del mateix banc de proves, vàrem implementar i millorar DACME, un mòdul de control d'admissió, capaç de proveir de qualitat de servici a transmissions de video unicast. DACME va provar ser una bona solució per obtindré un bon nivell de qualitat de servici en entorns de xarxes ad-hoc amb diversos salts. Si ens centrem a la transmissió de video multicast, vàrem implementar i simular diferents esquemes de difusió, específicament dissenyats per al seu ús a entorns VANET. La principal contribució d'aquesta tesi es l'esquema de difusió ACDB (Automatic Copies Distance Based). Fent ús de la densitat vehicular, ACDB es capaç d'obtindre una bona qualitat de video tant a ciutats com a vies interurbanes, sent a especialment efectiu a aquestes últimes. A més a més no es necessària cap configuració per part de l'usuari. / Torres Cortés, Á. (2016). Efficient real-time video delivery in vehicular networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62685 / TESIS

A mobile ad hoc network is a collection of wireless mobile devices which dynamically form a temporary network, without using any existing network infrastructure or centralised administration. Each node in the network effectively becomes a router, and forwards packets towards the packet’s destination node. Ad hoc networks are characterized by frequently changing network topology, multi-hop wireless connections and the need for dynamic, efficient routing protocols. <p.This work considers the routing problem in a network of uniquely addressable sensors. These networks are encountered in many industrial applications, where the aim is to relay information from a collection of data gathering devices deployed over an area to central points. The routing problem in such networks are characterised by: <ul> <li>The overarching requirement for low power consumption, as battery powered sensors may be required to operate for years without battery replacement;</li> <li>An emphasis on reliable communication as opposed to real-time communication, it is more important for packets to arrive reliably than to arrive quickly; and</li> <li>Very scarce processing and memory resources, as these sensors are often implemented on small low-power microprocessors.</li> </ul> This work provides overviews of routing protocols in ad hoc networks, swarm intelligence, and swarm intelligence applied to ad hoc routing. Various mechanisms that are commonly encountered in ad hoc routing are experimentally evaluated under situations as close to real-life as possible. Where possible, enhancements to the mechanisms are suggested and evaluated. Finally, a routing protocol suitable for such low-power sensor networks is defined and benchmarked in various scenarios against the Ad hoc On-Demand Distance Vector (AODV) algorithm. / Dissertation (MSc)--University of Pretoria, 2005. / Computer Science / Unrestricted

This diploma thesis is analysis of routing protocols used in MANET networks focusing on protocols OLSR, AODV and HWMP. The work consists of a theoretical and practical part. The theoretical part describes the routing protokols, which are used in MANET networks and their applications to FANET networks. In practical part, there are describes of created mobility model in the NS-3, which are used for comparison routing protocols on the created scenarios of mobility according to the qualitative parameters of the networks.

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).

The thesis deals with MANET networks and it focuses on the routing process. Most attention is paid to the routing protocols AODV and OLSR. These protocols are described in the detail. The aim of the thesis is to create a simulation model of MANET network in OPNET Modeler environment. In this model the AODV protocol is configured. In order to achieve improved characteristics of the network traffic the routing protocol parameters are optimized. Furthermore the process model of AODV protocol in this environment is studied and extended by a new type of message, which allows a transfer of current transmission speed of MANET station network interface. Current transmission rate of stations is retrieved from the statistics. Every station periodically sends a message to neighboring nodes. The node stores the information into the file when a new message arrives.