An architecture for adaptive replication-based multimedia streaming in P2P networks

This PhD thesis addresses the issue of scalable media streaming in large-scale networking environments. Multimedia streaming is one of the largest sink of network resources and this trend is still growing as testified by the success of services like Skype, Netflix, Spotify and Popcorn Time (BitTorrent-based). In traditional client-server solutions, when the number of consumers increases, the server becomes the bottleneck. To overcome this problem, the Content-Delivery Network (CDN) model was invented. In CDN model, the server copies the media content to some CDN servers, which are located in different strategic locations on the network. However, they require heavy infrastructure investment around the world, which is too expensive. Peer-to-peer (P2P) solutions are another way to achieve the same result. These solutions are naturally scalable, since each peer can act as both a receiver and a forwarder. Most of the proposed streaming solutions in P2P networks focus on routing scenarios to achieve scalability. However, these solutions cannot work properly in video-on-demand (VoD) streaming, when resources of the media server are not sufficient. Replication is a solution that can be used in these situations. This thesis specifically provides a family of replication-based media streaming protocols, which are scalable, efficient and reliable in P2P networks. First, it provides SCALESTREAM, a replication-based streaming protocol that adaptively replicates media content in different peers to increase the number of consumers that can be served in parallel. The adaptiveness aspect of this solution relies on the fact that it takes into account different constraints like bandwidth capacity of peers to decide when to add or remove replicas. SCALESTREAM routes media blocks to consumers over a tree topology, assuming a reliable network composed of homogenous peers in terms of bandwidth. Second, this thesis proposes RESTREAM, an extended version of SCALESTREAM that addresses the issues raised by unreliable networks composed of heterogeneous peers. Third, this thesis proposes EAGLEMACAW, a multiple-tree replication streaming protocol in which two distinct trees, named EAGLETREE and MACAWTREE, are built in a decentralized manner on top of an underlying mesh network. These two trees collaborate to serve consumers in an efficient and reliable manner. The EAGLETREE is in charge of improving efficiency, while the MACAWTREE guarantees reliability. Finally, this thesis provides TURBOSTREAM, a hybrid replication-based streaming protocol in which a tree overlay is built on top of a mesh overlay network. Both these overlays cover all peers of the system and collaborate to improve efficiency and low-latency in streaming media to consumers. This protocol is implemented and tested in a real networking environment using PlanetLab Europe testbed composed of peers distributed in different places in Europe.

Control de dispositivos con Android

Este proyecto de final de carrera de la titulación de Ingeniería en Informática de Gestión consiste en el diseño y desarrollo de un sistema de control de dispositivos conectados a Raspberry Pi y gestionados desde un dispositivo Android. Se podrán llevar a cabo diferentes acciones como encender, apagar, programar la calefacción y consultar la temperatura actual remotamente desde un dispostivo conectado a la red wifi doméstica o desde de cualquier red que esté conectada a internet.

The rare cancer network: ongoing studies and future strategy.

The Rare Cancer Network (RCN) was formed in the early 1990's to create a global network that could pool knowledge and resources in the studies of rare malignancies whose infrequency prevented both their study with prospective clinical trials. To date, the RCN has initiated 74 studies resulting in 46 peer reviewed publications. The First International Symposium of the Rare Cancer Network took place in Nice in March of 2014. Status updates and proposals for new studies were heard for fifteen topics. Ongoing studies continue for cardiac sarcomas, thyroid cancers, glomus tumors, and adult medulloblastomas. New proposals were presented at the symposium for primary hepatic lymphoma, solitary fibrous tumors, Rosai-Dorfman disease, tumors of the ampulla of Vater, salivary gland tumors, anorectal melanoma, midline nuclear protein in testes carcinoma, pulmonary lymphoepithelioma-like carcinoma, adenoid cystic carcinoma of the trachea, osteosarcomas of the mandible, and extra-cranial hemangiopericytoma. This manuscript presents the abstracts of those proposals and updates on ongoing studies, as well a brief summary of the vision and future of the RCN.

Same-Destination-Intermediate Grouping vs. End-to-End Grouping for Waveband Switching in WDM Mesh Networks

We investigate waveband switching (WBS) with different grouping strategies in wavelength-division multiplexing (WDM) mesh networks. End-to-end waveband switching (ETEWBS) and same-destination-intermediate waveband switching (SD-IT-WBS) are analyzed and compared in terms of blocking probability and cost savings. First, an analytical model for ETEWBS is proposed to determine the network blocking probability in a mesh network. For SD-IT-WBS, a simple waveband switching algorithm is presented. An analytical model to determine the network blocking probability is proposed for SD-IT-WBS based on the algorithm. The analytical results are validated by comparing with simulation results. Both results match well and show that ETE-WBS slightly outperforms SD-IT-WBS in terms of blocking probability. On the other hand, simulation results show that SD-IT-WBS outperforms ETE-WBS in terms of cost savings.

Libreria per comunicazioni ad-hoc per android basate su bluetooth

La tesi sviluppa, attraverso un processo definito e gestito, una libreria Android che permette di far comunicare diversi dispositivi mobili tramite Bluetooth. Inoltre gestisce: • le richieste di connessione sia che esse provengano dall’esterno, sia che partano dal dispositivo stesso; • la dinamicità del sistema utilizzando dispositivi mobili, cioè capaci di muoversi in diverse direzioni costantemente. In tal senso, la lista dei dispositivi vicini è costantemente aggiornata. • la comunicazione in stile Peer-to-Peer(P2P). In questo caso si viene a formare un gap in quanto la libreria Android di Bluetooth usa lo stile Master-Slave per i suoi dispositivi. Per colmare questo gap, la libreria sviluppata crea un layer soprastante la libreria Bluetooth di Android e maschera lo stile di comunicazione di quest’ultima a favo- re di una comunicazione paritaria, nella quale un dispositivo può sia accettare le richieste di connessione, sia connettersi ad altri dispositivi.

Sviluppo di sistemi mobile ad alta densita basati su comunicazioni opportunistiche wireless

In questa tesi ci si pone l'obiettivo di sviluppare sistemi distribuiti composti da device mobile che si scambiano informazioni tramite comunicazioni opportunistiche wireless peer-to-peer. Vengono inizialmente analizzate le principali tecnologie di comunicazione wireless adatte allo scopo, soffermandosi sulle reti Wifi ad hoc, delle quali vengono studiate le performance in sistemi di larga scala tramite il simulatore di reti ns-3. Successivamente viene esposto lo sviluppo di componenti software, basati su Akka Stream, per la costruzione di campi computazionali tramite comunicazioni opportunistiche tra device Android, effettuate tramite reti Wifi ad hoc.

A neural network algorithm to simplify 2D meshes

In this paper we propose a neural network model to simplify and 2D meshes. This model is based on the Growing Neural Gas model and is able to simplify any mesh with different topologies and sizes. A triangulation process is included with the objective to reconstruct the mesh. This model is applied to some problems related to urban networks.

Ferramenta de gestão de redes MESH

Mestrado em Engenharia Electrotécnica e de Computadores - Área de Especialização de Telecomunicações

Estudo e análise das redes centradas em conteúdos

A Internet, conforme a conhecemos, foi projetada com base na pilha de protocolos TCP/IP, que foi desenvolvida nos anos 60 e 70 utilizando um paradigma centrado nos endereços individuais de cada máquina (denominado host-centric). Este paradigma foi extremamente bem-sucedido em interligar máquinas através de encaminhamento baseado no endereço IP. Estudos recentes demonstram que, parte significativa do tráfego atual da Internet centra-se na transferência de conteúdos, em vez das tradicionais aplicações de rede, conforme foi originalmente concebido. Surgiram então novos modelos de comunicação, entre eles, protocolos de rede ponto-a-ponto, onde cada máquina da rede pode efetuar distribuição de conteúdo (denominadas de redes peer-to-peer), para melhorar a distribuição e a troca de conteúdos na Internet. Por conseguinte, nos últimos anos o paradigma host-centric começou a ser posto em causa e apareceu uma nova abordagem de Redes Centradas na Informação (ICN - information-centric networking). Tendo em conta que a Internet, hoje em dia, basicamente é uma rede de transferência de conteúdos e informações, porque não centrar a sua evolução neste sentido, ao invés de comunicações host-to-host? O paradigma de Rede Centrada no Conteúdo (CCN - Content Centric Networking) simplifica a solução de determinados problemas de segurança relacionados com a arquitetura TCP/IP e é uma das principais propostas da nova abordagem de Redes Centradas na Informação. Um dos principais problemas do modelo TCP/IP é a proteção do conteúdo. Atualmente, para garantirmos a autenticidade e a integridade dos dados partilhados na rede, é necessário garantir a segurança do repositório e do caminho que os dados devem percorrer até ao seu destino final. No entanto, a contínua ineficácia perante os ataques de negação de serviço praticados na Internet, sugere a necessidade de que seja a própria infraestrutura da rede a fornecer mecanismos para os mitigar. Um dos principais pilares do paradigma de comunicação da CCN é focalizar-se no próprio conteúdo e não na sua localização física. Desde o seu aparecimento em 2009 e como consequência da evolução e adaptação a sua designação mudou atualmente para Redes de Conteúdos com Nome (NNC – Named Network Content). Nesta dissertação, efetuaremos um estudo de uma visão geral da arquitetura CCN, apresentando as suas principais características, quais os componentes que a compõem e como os seus mecanismos mitigam os tradicionais problemas de comunicação e de segurança. Serão efetuadas experiências com o CCNx, que é um protótipo composto por um conjunto de funcionalidades e ferramentas, que possibilitam a implementação deste paradigma. O objetivo é analisar criticamente algumas das propostas existentes, determinar oportunidades, desafios e perspectivas para investigação futura.

Scalable and interference aware wi-fi mesh networks using cots devices

A crescente tendencia no acesso móvel tem sido potenciada pela tecnologia IEEE 802.11. Contudo, estas redes têm alcance rádio limitado. Para a extensão da sua cobertura é possível recorrer a redes emalhadas sem fios baseadas na tecnologia IEEE 802.11, com vantagem do ponto de vista do custo e da flexibilidade de instalação, face a soluções cabladas. Redes emalhadas sem fios constituídas por nós com apenas uma interface têm escalabilidade reduzida. A principal razão dessa limitação deve-se ao uso do mecanismo de acesso ao meio partilhado Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) em topologias multi-hop. Especificamente, o CSMA/CA não evita o problema do nó escondido levando ao aumento do número de colisões e correspondente degradação de desempenho com impacto direto no throughput e na latência. Com a redução da tecnologia rádio torna-se viável a utilização de múltiplos rádios por nó, sem com isso aumentar significativamente o custo da solução final de comunicações. A utilização de mais do que um rádio por nó de comuniações permite superar os problemas de desempenho inerentes ás redes formadas por nós com apenas um rádio. O objetivo desta tese, passa por desenvolver uma nova solução para redes emalhadas multi-cana, duar-radio, utilizando para isso novos mecanismos que complementam os mecanismos definidos no IEEE 802.11 para o estabelecimento de um Basic Service Set (BSS). A solução é baseada na solução WiFIX, um protocolo de routing para redes emalhadas de interface única e reutiliza os mecanismos já implementados nas redes IEEE 802.11 para difundir métricas que permitam à rede escalar de forma eficaz minimizando o impacto na performance. A rede multi-hop é formada por nós equipados com duas interfaces, organizados numa topologia hierárquica sobre múltiplas relações Access Point (AP) – Station (STA). Os resultados experimentais obtidos mostram a eficácia e o bom desempenho da solução proposta face à solução WiFIX original.

An automated framework for the management of P2P traffic in ISP infrastructures

Peer-to-Peer (P2P) is nowadays a widely used paradigm underpinning the deployment of several Internet services and applications. However, the management of P2P traffic aggregates is not an easy task for Internet Service Providers (ISPs). In this perspective, and considering an expectable proliferation in the use of such ap- plications, future networks require the development of smart mechanisms fostering an easier coexistence between P2P applications and ISP infrastructures. This paper aims to contribute for such research efforts presenting a framework incorporating useful mechanisms to be activated by network administrators, being also able to operate as an automated management tool dealing with P2P traffic aggregates.

StatusDroid : aplicació d'accés a la xarxa StatusNet per Android

Actualment en el món de les xarxes i el de les aplicacions mòbils està en contínua evolució i cada dia sorgeixen noves idees e implementacions que aprofundeixen en aquests aspectes. Aquest projecte uneix en un mateix desenvolupament tots dos punts presentant una aplicació Android per a connectar-se a la xarxa de microblogging lliure StatusNet.

Modular support for developing mobile ad hoc applications

Abstract This PhD thesis addresses the issue of alleviating the burden of developing ad hoc applications. Such applications have the particularity of running on mobile devices, communicating in a peer-to-peer manner and implement some proximity-based semantics. A typical example of such application can be a radar application where users see their avatar as well as the avatars of their friends on a map on their mobile phone. Such application become increasingly popular with the advent of the latest generation of mobile smart phones with their impressive computational power, their peer-to-peer communication capabilities and their location detection technology. Unfortunately, the existing programming support for such applications is limited, hence the need to address this issue in order to alleviate their development burden. This thesis specifically tackles this problem by providing several tools for application development support. First, it provides the location-based publish/subscribe service (LPSS), a communication abstraction, which elegantly captures recurrent communication issues and thus allows to dramatically reduce the code complexity. LPSS is implemented in a modular manner in order to be able to target two different network architectures. One pragmatic implementation is aimed at mainstream infrastructure-based mobile networks, where mobile devices can communicate through fixed antennas. The other fully decentralized implementation targets emerging mobile ad hoc networks (MANETs), where no fixed infrastructure is available and communication can only occur in a peer-to-peer fashion. For each of these architectures, various implementation strategies tailored for different application scenarios that can be parametrized at deployment time. Second, this thesis provides two location-based message diffusion protocols, namely 6Shot broadcast and 6Shot multicast, specifically aimed at MANETs and fine tuned to be used as building blocks for LPSS. Finally this thesis proposes Phomo, a phone motion testing tool that allows to test proximity semantics of ad hoc applications without having to move around with mobile devices. These different developing support tools have been packaged in a coherent middleware framework called Pervaho.

Iowa Plan for Brain Injury, 2007-2010

Traumatic Brain Injury (TBI) impacts the lives of thousands of Iowans every year. TBI has been described as the “Silent Epidemic” because so often the scars are not visible to others. The affects of brain injury are cognitive, emotional, social, and can result in physical disability. In addition to the overwhelming challenges individuals with brain injury experience, families also face many difficulties in dealing with their loved one’s injury, and in navigating a service delivery system that can be confusing and frustrating. In 1998, the Iowa Department of Public Health (IDPH) conducted a comprehensive statewide needs assessment of brain injury in Iowa. This assessment led to the development of the first Iowa Plan for Brain Injury, “Coming Into Focus.” An updated state plan, the Iowa Plan for Brain Injuries 2002 – 2005, was developed, which reported on progress of the previous state plan, and outlined gaps in service delivery in Iowa. Four areas of focus were identified by the State Plan for Brain Injuries Task Force that included: 1) Expanding the Iowa Brain Injury Resource Network (IBIRN); 2) Promoting a Legislative and Policy Agenda, While Increasing Legislative Strength; 3) Enhancing Data Collection; and, 4) Increasing Funding. The IDPH utilized “Coming Into Focus” as the framework for an application to the federal TBI State Grant Program, which has resulted in more than $900,000 for plan implementation. Iowa continues to receive grant dollars through the TBI State Grant Program, which focuses on increasing capacity to serve Iowans with brain injury and their families. Highlighting the success of this grant project, in 2007 the IDPH received the federal TBI Program’s “Impacting Systems Change” Award. The Iowa Brain Injury Resource Network (IBIRN) is the product of nine years of TBI State Grant Program funding. The IBIRN was developed to ensure that Iowans got the information and support they needed after a loved one sustained a TBI. It consists of a hospital and service provider pre-discharge information and service linkage process, a resource facilitation program, a peer-to-peer volunteer support network, and a service provider training and technical assistance program. Currently over 90 public and private partners work with the IDPH and the Brain Injury Association of Iowa (BIA-IA) to administer the IBIRN system and ensure that families have a relevant and reliable location to turn for information and support. Further success was accomplished in 2006 when the Iowa legislature created the Brain Injury Services Program within the IDPH. This program consists of four components focusing on increasing access to services and improving the effectiveness of services available to individuals with TBI and their families, including: 1) HCBS Brain Injury Waiver-Eligible Component; 2) Cost Share Component; 3) Neuro-Resource Facilitation; and, 4) Enhanced Training. The Iowa legislature appropriated $2.4 million to the Brain Injury Services Program in state fiscal year (SFY) 2007, and increased that amount to $3.9 million in SFY 2008. The Cost Share Component models the HCBS Brain Injury Waiver menu of services but is available for Iowans who do not qualify functionally or financially for the Waiver. In addition, the Neuro-Resource Facilitation program links individuals with brain injury and their families to needed supports and services. The Iowa Plan for Brain Injury highlights the continued need for serving individuals with brain injury and their families. Additionally, the Plan outlines the paths of prevention and services, which will expand the current system and direct efforts into the future.

Voltage fluctuations in IC power supply distribution

The supply voltage decrease and powerconsumption increase of modern ICs made the requirements for low voltage fluctuation caused by packaging and on-chip parasitic impedances more difficult to achieve. Most of the research works on the area assume that all the nodes of the chip are fed at thesame voltage, in such a way that the main cause of disturbance or fluctuation is the parasitic impedance of packaging. In the paper an approach to analyze the effect of high and fast current demands on the on-chip power supply network. First an approach to model the entire network by considering a homogeneous conductive foil is presented. The modification of the timing parameters of flipflops caused by spatial voltage drops through the IC surface are also investigated.