A mobile ad hoc network (MANET) is a collection of mobile platforms or nodes that come together to form a network capable of communicating with each other, without the help of a central controller. To avail the maximum potential of a MANET, it is of great importance to devise a routing scheme, which will optimize upon the performance of a MANET, given the high rate of random mobility of the nodes. In a MANET individual nodes perform the routing functions like route discovery, route maintenance and delivery of packets from one node to the other. Existing routing protocols flood the network with broadcasts of route discovery messages, while attempting to establish a route. This characteristic is instrumental in deteriorating the performance of a MANET, as resource overhead triggered by broadcasts is directly proportional to the size of the network. Bounded-dynamic source routing (B-DSR), is proposed to curb this multitude of superfluous broadcasts, thus enabling to reserve valuable resources like bandwidth and battery power. B-DSR establishes a bounded region in the network, only within which, transmissions of route discovery messages are processed and validated for establishing a route. All route discovery messages reaching outside of this bounded region are dropped, thus preventing the network from being flooded. In addition B-DSR also guarantees loop-free routing and is robust for a rapid recovery when routes in the network change.

Zone Routing Protocol (ZRP) is a typical hybrid routing protocol used in Mobile Ad Hoc Networks (MANETs). Hybrid routing protocols are especially suitable for dynamic environments because they combine the best features of proactive and reactive routing protocols. The Gossip-based Zone Routing Protocol (GZRP) uses a gossip scheme, in which the node forwards a packet to some nodes instead of all nodes to further reduce the control overhead. However, GZRP does not perform well when the network includes articulation points since packets will be lost if an articulation node happens not to forward the packet or nodes happen not to forward packets to the articulation point. To raise the packet delivery ratio, the gossip probability of articulation points must be set to 1 and the packets to be forwarded must be sent to the articulation points in peripheral nodes. Accordingly, how to identify articulation nodes in the network becomes a critical issue. This paper proposes an effective scheme, called articulation point detection (APD), to find the articulation points. Simulation results show that the proposed APD-GZRP (GZRP with articulation point detection) can improve the packet delivery ratio and reduce both the control overhead and power consumption.

Broadcasting is a communication model for a node to emit the packets via wireless channels to its neighbor nodes. In mobile ad hoc networks (MANETs), it is commonly implemented through flooding to find routes, send alarm signals and page a particular host. Conventionally, ad hoc routing protocols, such as AODV, use blind flooding extensively for on-demand route discovery, which could result in a high number of redundant retransmissions, leading to serious contention and collisions referred to as the broadcast storm problem. A gossip-based approach, in which each node forwards a message with some probability, has been proposed in past years to alleviate this problem. The approach combines gossiping with AODV (denoted as AODV+G) and exhibits a significant performance improvement in simulations. In this paper, we make a mathematical inference from observing the behavior of the gossip-based approach, and improve the gossip-based approach by employing the remaining energy of nodes in the gossip mechanism (denoted as AODV+GE) to extend the lifetime of the entire network and improve the packet delivery ratio. Through mathematical inference and simulations we show that AODV+GE outperforms AODV+G in terms of the lifetime of the whole network, average node energy consumption, and packet delivery ratio.

Adhoc networks do not depend on any fixed infrastructure. The most outstanding features of adhoc networks are non-centralized structure and dynamic topology change due to high mobility. Since mentioned dynamics of mobile adhoc networks complicate reaching the resources in the network, service discovery is significantly an important part of constructing stand-alone and self-configurable mobile adhoc networks. The heterogeneity of the devices and limited resources such as battery are also load up more difficulty to service discovery. Due to the volatile nature of the adhoc networks, service discovery algorithms proposed for mobile and adhoc networks suffer from some problems. Scalability becomes a problem when the service discovery is based on flooding messages over the network. Furthermore, the high traffic which occurs due to the message exchange between network nodes makes the communication almost impossible. Partitioning a network into sub-networks is an efficient way of handling scalability problem. In this thesis, a mobility based service discovery algorithm for clustered MANET is presented. The algorithm has two main parts. First one is for partitioning the MANET into sub-networks, named &ldquo / clustering&rdquo / . Second part is composed of an efficient discovery of services on overall network. Clustering algorithm used in this study is enhanced version of DMAC (Distributed Mobility Adaptive Clustering, which is one of the golden algorithms of the wireless network clustering area). To be fast and flexible in service discovery layer, a simple and fastresponding algorithm is implemented. Integration of two algorithms enables devices to be mobile in the network

<p>Distributed real-time databases can be used to support data sharing</p><p>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.</p><p>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</p><p>state and update conflicts. A basic simulator for mobile ad-hoc networks has been developed to validate that pPRiDe provides eventual consistency.</p><p>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.</p><p>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.</p>

En este trabajo se presenta el estudio de un caso de integración de una MANET, desplegada en una zona remota, a una red de infraestructura. La finalidad principal es la de proporcionar, a los nodos de la red ad hoc, acceso “seguro” a un servidor de la red de infraestructura, sin comprometer recursos como ancho de banda y energía que son limitados en la zona de despliegue. Para ello, se implemento un escenario de pruebas que comprende el despliegue de una MANET en zona remota y la integración de la misma a una red de infraestructura a través de la red celular. Sobre el escenario propuesto se establecieron canales de comunicación extremo a extremo, entre un nodo de la MANET y un servidor de infraestructura. Inicialmente, se realizaron pruebas inyectando tráfico de datos sobre un canal “no seguro” para obtener valores de referencia para latencia, throughput y consumo de energía. Luego, se efectuaron las mismas pruebas utilizando canales de comunicación “seguros” configurados sobre protocolos IPSEC y SSL/TLS. Los resultados obtenidos utilizando canales “seguros” fueron comparados con los valores de referencia para determinar las diferencias de consumo de recursos. Las desviaciones que surgieron de estas comparaciones, permitieron: - Establecer el consumo adicional de recursos generado por el uso de protocolos seguros. - Realizar un estudio comparativo de rendimiento, entre diferentes configuraciones de protocolos de seguridad. - Determinar que protocolo seguro se adapta mejor a este tipo de entornos.

Edouard Manet, Edgar Degas and Mary Cassatt had unique visions of the Paris Opera House. Thus each artist perceived and portrayed the pageant of fashionable contemporary life at the Opera from diverse perspectives. Manet rendered a singular image of this world, that of a masked ball, which elicits an extraordinary insight into the manners and mores of an era. The focus by Degas on the dancers on stage invites a penetrating look into the spectacle of the performance from exceptional viewpoints. Mary Cassatt's depictions, exclusively of the female spectators in the audience, intimate a serious reflection of her earnest feminist attitudes. / From the costumed revellers in the foyer, to the brilliant presentation on stage to the elegant spectators in the loges, these images inspired by the Opera endure as remarkably distinctive.

Each day, the dream of seamless networking and connectivity everywhere is getting closer to become a reality. In this regard, mobile Ad-Hoc networks (MANETs) have been a hot topic in the last decade; but the amount of MANET usage nowadays confines to a tiny percentage of all our network connectivity in our everyday life, which connectivity through infrastructured networks has the major share. On the other hand, we know that future of networking belongs to Ad-Hocing , so for now we try to give our everyday infrastructure network a taste of Ad-Hocing ability; these types of networks are called Wireless Mesh Networks (WMN) and routing features play a vital role in their functionality. In this thesis we examine the functionality of 3 Ad-Hoc routing protocols known as AODV, OLSR and GRP using simulation method in OPNET17.5. For this goal we set up 4 different scenarios to examine the performance of these routing protocols; these scenarios vary from each other in amount of nodes, background traffic and mobility of the nodes. Performance measurements of these protocols are done by network throughput, end-end delay of the transmitted packets and packet loss ratio as our performance metrics. After the simulation run and gathering the results we study them in a comparative view, first based on each scenario and then based on each protocol. For conclusion, as former studies suggest AODV, OLSR and DRP are among the best routing protocols for WMNs, so in this research we don’t introduce the best RP based on the obtained functionality results, instead we discuss the network conditions that each of these protocols show their best functionality in them and suggest the best routing mechanism for different networks based on the analysis from the former part.

Le point de départ pour les systèmes décentralisés a été l'échange des fichiers, en utilisant cet approche i) pour distribuer la bande passante entre tous les nœuds concernés et ii) pour augmenter la robustesse en éliminant autant que possible les points individuels de défaillance et de contrôle et iii) en partageant également les responsabilités entre les nœuds. Si les approches le plus décentralisés sont très efficaces en termes de résilience aux pannes, pour la même raison, les performances sont limités et difficiles à analyser quand on observe plusieurs réseaux interconnectés entre eux, configurations qui peuvent être analysés à travers des outils de simulation, souvent peu efficaces dans l'analyse de l'espace de possibilités. Dans cette thèse on a développé un modèle mathématique pour la modélisation de l'interconnexion des réseaux en permettant l'étude et l'exploration d'équilibres qui grâce à l'abstraction du modèle peuvent s'appliquer à l'interconnexion des réseaux de communications, réseaux de distribution de marchandise ou réseaux de distribution d'eau. La thèse se focalise aussi sur les réseaux décentralisés MANET, ou' la communication entre nœuds mobiles est purement ≪ ad-hoc ≫ (ex: deux voitures communiquant entre eux quand ils sont proches) en utilisant i) des ≪ rateless coding ≫ pour augmenter la robustesse et minimiser la perte ou la corruption de données causées par la non fiabilité du moyen de transmission et ii) des algorithmes de ≪ pollution détection ≫, par exemple de détection de nœuds malveillants ou de paquets corrompus, cette détection et prévention étant très difficile dans des environnements fortement distribués.

資訊世代的來臨，手機、筆記型電腦、iPod、iPad不勝枚舉的手持行動裝置充斥在我們的生活周遭。這些裝置上都擁有一種以上的無線網路介面，例如:紅外線、藍芽、WiFi，及行動網路介面等。由於手持裝置的盛行，構成行動隨意網路(Mobile Ad Hoc Network)的傳輸空間越來越普遍，伴隨而來的問題如節點可能任意移動，拓樸不斷改變等，造成傳輸中斷。而在有網路的環境下如何從較信任的人(節點)獲取較可信任的資訊，將是重要的議題。因此本論文導入目前炙手可熱與我們生活密不可分的社群網路(social network)，利用社會網路分析(social network analysis)將人與人之間關係數據化，做為轉傳依據。我們提出Ego-Centric Social Network Routing中繼節點 (relay node) 選擇的策略，簡稱ECSNR。除了利用社會網路分析的方法外也加入候選清單，使負載過重的節點直接由清單中之候選節點協助轉傳、推薦清單，讓路由中繼的位置更靠近負載過重之節點，加速訊息的傳遞，也可藉由緊密度高且較可信任之節點協助傳送。另外當訊息無法藉由社會網路輔助(social networking aided)傳輸時，便會利用興趣導向(interest-based)傳輸，依照節點興趣相似性判別興趣區間，將訊息傳遞出去。最後，由實驗模擬結果得知，當網路節點數量增加時，封包送達率能有7.4%~15.8%的改善。End to end delay有10%~15.2%的改善；control overhead雖然較遜色，但依然平均控制在9.4%內。Average hop count平均減少1.7 個hops數。網路移動速度比較的實驗中，封包送達率能有8%~24.2%的改善；control overhead雖然較遜色，但依然平均控制在8.8%內。End to end delay有約4.7%~15.2%的改善；average hop count平均減少2.4個hops數。 / With the coming of information era, our lives have been filled with varied mobile devices, such as cell phones, notebooks, iPods, and iPads. All these devices are equipped with more than one wireless network interface, including Infrared, Bluetooth, WiFi, mobile network interface etc. Due to the popularity of mobile devices, Mobile Ad Hoc Networks have been more widespread than ever. However, movable nodes and the constantly changing topology could cause transmission interruption. Therefore, “how to obtain trustworthy information from trusty nodes” is a significant issue. This thesis geared toward the social network which is inseparable from our lives at this moment. In this thesis, social network analysis is employed, and the relationship data is used as the base of relay. We propose a relay-node selection strategy of Ego-Centric Social Network Routing (ECSNR), and apply the method of using candidate list. All these can be used to speed up the transmission process. Because the candidate nodes are the closest ones to the overloaded nodes, the relay process can be more efficient and speedy. The transmission can also be done through the stable and trustworthy nodes. When a message can not be transmitted through the social network aided nodes, the interest based nodes can help to transmit according to the interest similarity. The results of experiment simulations show that along with the increase of network nodes, the packet delivery ratio can be improved by 7.4% ~ 15.8%. The end to end delay can be improved by 10% ~ 15.2%, and the average control overhead is within 9.4%. The average hop count can be reduced by 1.7 hops. Given the nodes are moving, the packet delivery ratio can be improved by 8%~24.2%, and the average control overhead is within 8.8%. The end to end delay can be improved by 4.7% ~ 15.2%, and the average hop count can be reduced by 2.4 hops.