A Review of the Energy Efficient and Secure Multicast Routing Protocols for Mobile Ad hoc Networks

This paper presents a thorough survey of recent work addressing energy efficient multicast routing protocols and secure multicast routing protocols in Mobile Ad hoc Networks (MANETs). There are so many issues and solutions which witness the need of energy management and security in ad hoc wireless networks. The objective of a multicast routing protocol for MANETs is to support the propagation of data from a sender to all the receivers of a multicast group while trying to use the available bandwidth efficiently in the presence of frequent topology changes. Multicasting can improve the efficiency of the wireless link when sending multiple copies of messages by exploiting the inherent broadcast property of wireless transmission. Secure multicast routing plays a significant role in MANETs. However, offering energy efficient and secure multicast routing is a difficult and challenging task. In recent years, various multicast routing protocols have been proposed for MANETs. These protocols have distinguishing features and use different mechanismsComment: 15 page

Vitis: A Gossip-based Hybrid Overlay for Internet-scale Publish/Subscribe

Peer-to-peer overlay networks are attractive solutions for building Internet-scale publish/subscribe systems. However, scalability comes with a cost: a message published on a certain topic often needs to traverse a large number of uninterested (unsubscribed) nodes before reaching all its subscribers. This might sharply increase resource consumption for such relay nodes (in terms of bandwidth transmission cost, CPU, etc) and could ultimately lead to rapid deterioration of the system’s performance once the relay nodes start dropping the messages or choose to permanently abandon the system. In this paper, we introduce Vitis, a gossip-based publish/subscribe system that significantly decreases the number of relay messages, and scales to an unbounded number of nodes and topics. This is achieved by the novel approach of enabling rendezvous routing on unstructured overlays. We construct a hybrid system by injecting structure into an otherwise unstructured network. The resulting structure resembles a navigable small-world network, which spans along clusters of nodes that have similar subscriptions. The properties of such an overlay make it an ideal platform for efficient data dissemination in large-scale systems. We perform extensive simulations and evaluate Vitis by comparing its performance against two base-line publish/subscribe systems: one that is oblivious to node subscriptions, and another that exploits the subscription similarities. Our measurements show that Vitis significantly outperforms the base-line solutions on various subscription and churn scenarios, from both synthetic models and real-world traces

A Web-Based Collaborative Multimedia Presentation Document System

With the distributed and rapidly increasing volume of data and expeditious development of modern web browsers, web browsers have become a possible legitimate vehicle for remote interactive multimedia presentation and collaboration, especially for geographically dispersed teams. To our knowledge, although there are a large number of applications developed for these purposes, there are some drawbacks in prior work including the lack of interactive controls of presentation flows, general-purpose collaboration support on multimedia, and efficient and precise replay of presentations. To fill the research gaps in prior work, in this dissertation, we propose a web-based multimedia collaborative presentation document system, which models a presentation as media resources together with a stream of media events, attached to associated media objects. It represents presentation flows and collaboration actions in events, implements temporal and spatial scheduling on multimedia objects, and supports real-time interactive control of the predefined schedules. As all events are represented by simple messages with an object-prioritized approach, our platform can also support fine-grained precise replay of presentations. Hundreds of kilobytes could be enough to store the events in a collaborative presentation session for accurate replays, compared with hundreds of megabytes in screen recording tools with a pixel-based replay mechanism

Mecanismos para gerenciamento de banda passante em redes ópticas passivas Ethernet com clientes locatários de múltiplas unidades ópticas de redes

Orientador: Nelson Luis Saldanha da FonsecaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: As atuais redes de acesso banda larga à Internet necessitam dar suporte às altas demandas de diversas aplicações tais como voz sobre IP (VoIP), streaming de vídeo UHD, videoconferência, internet das coisas (IoT) e jogos interativos. A tecnologia de redes ópticas passivas (PONs) é considerada promissora para fornecer alta capacidade de acesso com um custo-benefício aceitável. Existem duas diferentes tecnologias que disputam o mercado das redes ópticas; Ethernet PON (EPON) e Gigabit Capable PON(GPON). Devido ao alto custo de aquisição e manutenção de uma infraestrutura PON, muitas empresas (clientes) recorrem a fornecedores de infraestrutura (InP) para reduzir os altos custo, por meio do aluguel de uma porção dos recursos da PON. Esses clientes podem ser, por exemplo, operadores de rede móvel ou provedores de serviços virtuais, que podem adquirir múltiplas unidades da rede óptica (ONU) conectadas em uma única PON. Essa facilidade de alugar múltiplas ONUs pode gerar problemas de balanceamento de carga entre ONUs, uma vez que os atuais algoritmos de alocação de banda passante (DBA) são capazes de garantir banda para uma única ONU. Consequentemente, picos de demanda de banda passante podem ultrapassar a banda garantida em algumas ONUs e, ao mesmo tempo, subutilizar a banda garantida em outras ONUs de um mesmo cliente. Nesta dissertação, aborda-se o problema de gerenciamento de largura de banda para clientes multi-ONU nas redes EPON. Propõe-se um algoritmo de alocação dinâmica de banda passante (DBA) (MOS-IPACT) para dar suporte ao contrato de serviço (SLA) para clientes com várias ONUs. O mecanismo proposto distribui a largura de banda agregada entre ONUs de um mesmo cliente, com o objetivo de melhorar a utilização da largura de banda. Além disso propõe-se um algoritmo DBA para EPONs (subMOSIPACT) com o objetivo de garantir banda passante em diferentes níveis de granularidade. Este algoritmo é fundamental para clientes multi-ONU e que oferecem diversos tipos de serviços. Por exemplo, um operador da rede virtual pode alugar as ONUs de um InP para oferecer serviços corporativos e residenciais. Introduz-se, também, um algoritmo DBA para EPONs (coopMOS-IPACT) que permite a cooperação entre clientes. O algoritmo proposto permite que clientes cooperativos compartilhem banda passante não utilizada a fim de aumentar a banda disponível para alocação mas sem afetar seus SLAs individuais. Os resultados mostram que os três algoritmos propostos são capazes de garantir banda passante para clientes multi-ONU, mesmo em condições de tráfego desbalanceadas; Além de garantir banda passante em diferentes níveis de granularidade aumentando o suporte aos requisitos de qualidade de serviço (QoS). Resultados derivados por simulação mostraram que os algoritmos distribuem eficientemente a largura de banda entre os clientes multi-ONU bem como para clientes convencionais que possuem uma única ONU. Por fim, este trabalho mostra os benefícios do modelo de clientes cooperativos para aumentar a largura de banda disponívelAbstract: Current broadband access networks need to support the Quality of Service (QoS) requirements of diverse application such as voice over IP (VoIP), ultra-high video streaming, video conferencing, Internet of Things (IoT) and interactive gaming. Passive Optical Networks (PONs) is considered a promising solution to provides high access capacity with acceptable cost-benefit. Two different technologies share the optical access networks market: Ethernet PON (EPON) and Gigabit Capable PON (GPON). However, the deployment of PON infrastructure involves significant costs. On the other hand, Infrastructure Provider (InP) can alleviate these costs by leasing their PONs to several enterprises (customers). These customers can be Mobile Network Operators (MNOs), multi-site enterprises, or virtual service providers. New scenarios are envisioned in which customers owning multiple Optical Network Units (ONUs) (multi-ONUs customers) are connected to a single PON. However, current EPON Dynamic Bandwidth Allocation (DBA) algorithms are able to support only guaranteed bandwidth for individual ONUs. Consequently, peaks of bandwidth demand may surpass the guaranteed bandwidth for some ONUs and, at the same time, underutilize the bandwidth in other ONUs of a multi-ONU customer. In this work, the bandwidth management problem for multi-ONU customers in EPON network is addressed. This dissertation proposes a mechanisms for the support of multiONU Service Level Agreements (SLA) in DBA algorithms for EPONs. The proposed DBA algorithms (MOS-IPACT) allows customers owning multiple ONUs to redistribute the aggregated bandwidth of the group of ONUs to better balance the bandwidth utilization. This dissertation also proposes a DBA algorithm for EPON networks (subMOS-IPACT) with the objective of assuring bandwidth at different levels of granularity. This algorithm is quite important for multi-ONU customers offering diverse type of services. For example, a virtual network operator can lease ONUs from an InP to offer enterprise and residential services to its client.This work also introduce a DBA algorithm for EPONs (coopMOS-IPACT), which allows cooperation between customers. The proposed DBA algorithm allows cooperative customers share the unused bandwidth without affecting their individual multi-ONU SLAs. Results show that the three proposed Dynamic Bandwidth Allocation (DBA) algorithms are able to guarantee bandwidth for multi-Optical Network Unit (ONU) customers even in unbalancing traffic conditions. Furthermore, assuring bandwidth at different levels of granularity improves the Quality of Service (QoS) providing. Simulation results showed that the mechanisms efficiently distributes bandwidth between multi-ONU customers and traditional customers owning a single ONU. Finally, this work show the benefits of cooperative customers model in order to increase the available bandwidthMestradoCiência da ComputaçãoMestre em Ciência da Computação132308/2016-9CNP

SOFTWARE AND HARDWARE DESIGN OF A MINIATURIZED MOBILE AUTONOMOUS ROBOT, OPERATING IN A WIRELESS SENSOR NETWORK

Nowadays wireless nodes are becoming more and more popular in the field of localization. Thanks to the high research effort in this area, wireless sensors become more and more sophisticated. From year to year the accuracy in terms of distance estimation increases. In comparison to other localization devices like a Local Positioning System (LPS) or Global Positioning System (GPS), the wireless nodes are considered as a cheap alternative. The Finnish defence department, police and fire department support current research activities within this area, in the hope that they will get beneficial applications. The target of this Master’s Thesis “Software and Hardware Design of a Miniaturized Mobile Autonomous Robot, Operating in a Wireless Sensor Network” was the construction of miniaturized autonomous robot acting within a Wireless Sensor Network (WSN). The robot consists of an Embedded Linux PC, a wireless node and a mobile platform that are connected with each other. In this Master’s Thesis we describe the software and hardware tasks that were necessary for the interaction between the three mentioned components. We also discuss the software implementation for the communication between the wireless nodes and the results of the distance measurements.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Efficient Buffer Management Protocol for Multicast Streaming in MANET

AbstractBuffer management techniques are essential while handling multicast streaming in MANET since real-time data will involve playback delay and jitter. In this paper, an efficient buffer management protocol is developed for streaming data in multicast groups. The frequently requested video data can be buffered in any intermediate nodes along the multicast tree from the source to the receivers. When packets are received, they are classified as real-time or non-real-time and placed into respective queues. Cumulative weight of the packets in the real-time buffer is then estimated based on number of hops, deadline and waiting time. Based on the estimated weight value, transmission priorities are assigned. The buffer space is dynamically adjusted depending on the number of intermediate nodes along the multicast tree from the source to the receivers. Simulation results show that the proposed buffer management protocol reduces the latency and energy consumption while increasing the packet delivery ratio

Fast factorisation of probabilistic potentials and its application to approximate inference in Bayesian networks

We present an efficient procedure for factorising probabilistic potentials represented as probability trees. This new procedure is able to detect some regularities that cannot be captured by existing methods. In cases where an exact decomposition is not achievable, we propose a heuristic way to carry out approximate factorisations guided by a parameter called factorisation degree, which is fast to compute. We show how this parameter can be used to control the tradeoff between complexity and accuracy in approximate inference algorithms for Bayesian networks