In order to speedup the encoding process of H.264/AVC and Scalable Video Coding (SVC), Temporal and Spatial Correlation-based Merging and Splitting (TSCMS) fast mode decision algorithm and Coded Block Pattern (CBP)-based fast mode decision algorithm are proposed in this thesis. TSCMS and CBP-based fast mode decision algorithms are applied to H.264/AVC and SVC, respectively. In TSCMS, Temporal Correlation (TC) is used to predict the Motion Vectors (MVs) of 8¡Ñ8 blocks in each macroblock. In addition, the merging and splitting procedure is adopted to predict the motion vectors of other blocks. Afterwards, the spatial correlation is performed to merge 16¡Ñ16 blocks instead of the conventional merge scheme. CBP value is the syntax used at each Macroblock (MB) header to indicate whether an MB contains residual information or not in CBP-based fast mode decision algorithm. The proposed algorithm can exclude the invalid modes for the mode prediction of the current MB in Enhancement Layer (EL) through the CBP values and MB modes of adjacent MBs in EL and the co-located Base Layer (BL) MB modes. Experimental results show that the proposed algorithms reduce computations significantly with negligible PSNR degradation and bit increase when compared to JM 12.3, JSVM 9.12, and the other existing methods.

Video streaming on the Internet is increasingly using Dynamic Adaptive Streaming over HTTP (DASH), in which the video is converted into various quality levels and divided into two-second segments. A client can then adjust its video quality over time by choosing to download the appropriate quality level for a given segment using standard HTTP. Scalable Video Coding (SVC) is a promising enhancement to the DASH protocol. With SVC, segments are divided into subset bitstream blocks. At playback, blocks received for a given segment are combined to additively increase the current quality. Unlike traditional DASH, which downloads segments serially, this encoding creates a large space of possible ways to download a video; for example, if given a variable download rate, when should the client try to maximize the current segment's video quality, and when should it instead play it safe and ensure a minimum level of quality for future segments? In this work, we examine the impact of SVC on the client's quality selection policy, with the goal of maximizing a performance metric quantifying user satisfaction. We use acombination of analysis, dynamic programming, and simulation to show that, in many cases, a client should use a diagonal quality selection policy, balancing both of the aforementioned concerns, and that the slope of the best policy flattens out as the variation in download rateincreases.

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To reinforce its Inez network, which was operated close to its stability limits, American Electric Power (AEP) undertook two major developments, one being the installation of a Static Var Compensator (SVC) in November, 1980 and the other one being the installation of the world's first Unified Power Flow Controller (UPFC) in 1998. The controllers in the system include the Automatic Voltage Regulators (AVRs) of the generators, the controllers of the SVC, and UPFC. To coordinate the control actions of these controllers and prevent voltage instability resulting from their fighting against each other, a two level hierarchical control scheme using fuzzy logic has been developed and its performance was assessed via simulations. The second level of the hierarchy determines the set points of the local controllers of the AVRs, SVC, and UPFC and defines the switching sequences of the capacitor banks, the goal being to maximize the reactive reserve margins of the Inez subsystem. Numerous simulations were carried out on this system to determine the actions of the fuzzy controller required to prevent the occurrence of voltage collapse under double contingency. Simulations have revealed the occurrence of nonlinear interactions between the machines resulting in stable limit cycles, nonlinear oscillations undergoing period doubling leading to chaos and possible voltage collapse. The proposed fuzzy scheme provides a fast, simple and effective way to stretch the stability limit of the system for double contingency conditions, up to 175 MW in some cases. This is a significant increase in the system capacity. / Master of Science

Les réseaux opportunistes sont des réseaux mobiles qui se forment spontanément et de manière dynamique grâce à un ensemble d'utilisateurs itinérants dont le nombre et le déplacement ne sont pas prévisibles. En conséquence, la topologie et la densité de tels réseaux évoluent sans cesse. La diffusion de bout-en-bout d'informations, dans ce contexte, est incertaine du fait de la forte instabilité des liens réseaux point à point entre les utilisateurs. Les travaux qui en ont envisagé l'usage visent pour la plupart des applications impliquant l'envoi de message de petite taille. Cependant, la transmission de données volumineuses telles que les vidéos représente une alternative très pertinente aux réseaux d'infrastructure, en cas d'absence de réseau, de coût important ou pour éviter la censure d'un contenu. La diffusion des informations de grande taille en général et de vidéos en particulier dans des réseaux oppnets constitue un challenge important. En effet, permettre, dans un contexte réseau très incertain et instable, au destinataire d’une vidéo de prendre connaissance au plus vite du contenu de celle-ci, avec la meilleure qualité de lecture possible et en encombrant le moins possible le réseau reste un problème encore très largement ouvert. Dans cette thèse, nous proposons un nouveau mécanisme de diffusion de vidéos dans un réseau opportuniste de faible densité, visant à améliorer le temps d'acheminement de la vidéo tout en réduisant le délai de lecture à destination. La solution proposée se base sur le choix d'encoder la vidéo en utilisant l'encodage SVC, grâce auquel la vidéo se décline en un ensemble de couches interdépendantes (layers), chacune améliorant la précédente soit en terme de résolution, soit en terme de densité, soit en terme de perception visuelle. Notre solution se décline en trois contributions. La première consiste à proposer une adaptation du mécanisme de diffusion Spray-and-Wait, avec comme unités de diffusion, les couches produites par SVC. Les couches sont ainsi diffusées avec un niveau de redondance propre à chacune, adapté à leur degré d'importance dans la diffusion de la vidéo. Notre seconde contribution consiste à améliorer le mécanisme précédent en prenant en compte une granularité plus fine et adaptative en fonction de l'évolution de la topologie du réseau. Cette amélioration a la particularité de ne pas engendrer de coût de partitionnement, les couches vidéos dans l'encodage SVC étant naturellement déclinées en petites unités (NALU) à base desquelles l'unité de transfert sera calculée. Enfin, la troisième contribution de cette thèse consiste à proposer un mécanisme hybride de complétion des couches vidéos arrivées incomplètes à destination. Cette méthode se caractérise par le fait d'être initiée par le destinataire. Elle combine un protocole de demande des parties manquantes aux usagers proches dans le réseau et des techniques de complétion de vidéo à base d’opérations sur les frames constituant la vidéo. / Opportunistic networks are human-centric mobile ad-hoc networks, in which neither the topology nor the participating nodes are known in advance. Routing is dynamically planned following the store-carry-and-forward paradigm, which takes advantage of people mobility. This widens the range of communication and supports indirect end-to-end data delivery. But due to individuals’ mobility, OppNets are characterized by frequent communication disruptions and uncertain data delivery. Hence, these networks are mostly used for exchanging small messages like disaster alarms or traffic notifications. Other scenarios that require the exchange of larger data are still challenging due to the characteristics of this kind of networks. However, there are still multimedia sharing scenarios where a user might need switching to an ad-hoc alternative. Examples are the cases of 1) absence of infrastructural networks in far rural areas, 2) high costs due limited data volumes or 3) undesirable censorship by third parties while exchanging sensitive content. Consequently, we target in this thesis a video dissemination scheme in OppNets. For the video delivery problem in the sparse opportunistic networks, we propose a solution that encloses three contributions. The first one is given by granulating the videos at the source node into smaller parts, and associating them with unequal redundancy degrees. This is technically based on using the Scalable Video Coding (SVC), which encodes a video into several layers of unequal importance for viewing the content at different quality levels. Layers are routed using the Spray-and-Wait routing protocol, with different redundancy factors for the different layers depending on their importance degree. In this context as well, a video viewing QoE metric is proposed, which takes the values of the perceived video quality, delivery delay and network overhead into consideration, and on a scalable basis. Second, we take advantage of the small units of the Network Abstraction Layer (NAL), which compose SVC layers. NAL units are packetized together under specific size constraints to optimize granularity. Packets sizes are tuned in an adaptive way, with regard to the dynamic network conditions. Each node is enabled to record a history of environmental information regarding the contacts and forwarding opportunities, and use this history to predict future opportunities and optimize the sizes accordingly. Lastly, the receiver node is pushed into action by reacting to missing data parts in a composite backward loss concealment mechanism. So, the receiver asks first for the missing data from other nodes in the network in the form of request-response. Then, since the transmission is concerned with video content, video frame loss error concealment techniques are also exploited at the receiver side. Consequently, we propose to combine the two techniques in the loss concealment mechanism, which is enabled then to react to missing data parts.

Pour avoir une idée sur la qualité du réseau, la majorité des acteurs concernés (opérateurs réseau, fournisseurs de service) se basent sur la Qualité de Service (Quality of Service). Cette mesure a montré des limites et beaucoup d’efforts ont été déployés pour mettre en place une nouvelle métrique qui reflète, de façon plus précise, la qualité du service offert. Cette mesure s’appelle la qualité d’expérience (Quality of Experience). La qualité d’expérience reflète la satisfaction de l’utilisateur par rapport au service qu’il utilise. L’évaluation de la qualité d’expérience est devenue primordiale pour les fournisseurs de services et les fournisseurs de contenus. Cette nécessité nous a poussés à innover et mettre en place des nouvelles méthodes pour estimer la QoE. Dans cette thèse, nous travaillons sur l’estimation de la QoE dans le cas des communications Voix sur IP et dans le cas de la vidéo sur IP. Nous étudions les performances et la qualité des codecs iLBC, Speex et Silk pour la VoIP et les codecs MPEG-2 et H.264/SVC pour la vidéo sur IP. Nous étudions l’impact que peut avoir la majorité des paramètres réseaux, des paramètres sources (au niveau du codage) et destinations (au niveau du décodage) sur la qualité finale. Afin de mettre en place des outils précis d’estimation de la QoE en temps réel, nous nous basons sur la méthodologie Pseudo-Subjective Quality Assessment. La méthodologie PSQA est basée sur un modèle mathématique appelé les réseaux de neurones artificiels. En plus des réseaux de neurones, nous utilisons la régression polynomiale pour l’estimation de la QoE dans le cas de la VoIP. / Quality of Experience (QoE) is the key criteria for evaluating the Media Services. Unlike objective Quality of Service (QoS) metrics, QoE is more accurate to reflect the user experience. The Future of Internet is definitely going to be Media oriented. Towards this, there is a profound need for an efficient measure of the Quality of Experience (QoE). QoE will become the prominent metric to consider when deploying Networked Media services. In this thesis, we provide several methods to estimate the QoE of different media services: Voice and Video over IP. We study the performance and the quality of several VoIP codecs like iLBC, Speex and Silk. Based on this study, we proposed two methods to estimate the QoE in real-time context, without any need of information of the original voice sequence. The first method is based on polynomial regression, and the second one is based on an hybrid methodology (objective and subjective) called Pseudo-Subjective Quality Assessment. PSQA is based on the artificial neural network mathematical model. As for the VoIP, we propose also a tool to estimate video quality encoded with MPEG-2 and with H.264/SVC. We studied also the impact of several network parameters on the quality, and the impact of some encoding parameters on the SVC video quality. We tested also the performance of several SVC encoders and proposed some SVC encoding recommendations.

Le but de cette thèse est de proposer des mécanismes efficaces pour l'ordonnancement des chunks et l'allocation de la bande passante dans le contexte de la transmission vidéo sur les réseaux P2P,afin d'offrir une meilleure qualité de service pour l'utilisateur final. Dans un premier temps nousavons proposé un mécanisme d'ordonnancement des chunks pour la transmission de vidéomulticouche dans les réseaux P2P. Le mécanisme proposé est basé sur une nouvelle technique quipermet de sélectionner les chunks adéquats et les demander des pairs les plus appropriés. Ensuitenous avons proposé un mécanisme d'allocation de la bande passante, toujours dans le cadre detransmission de vidéo multicouche dans les réseaux P2P. Le pair émetteur organise une enchère pour«vendre » sa bande passante. L'allocation tient en considération la priorité des pairs et l'importancedes couches demandées. Finalement nous avons proposé un mécanisme d'adaptation lisse « smooth» d'une vidéo multicouche transportée sur un réseau P2P.Après une introduction, nous présentons dans le chapitre 2 les motivations du travail le but du travailet les problèmes recherche qui demeurent. Dans ce chapitre nous présentons les composants dessystèmes P2P et tout particulièrement la distribution et l'adaptation de contenus. Dans ce cadre,nous proposons une classification des applications de streaming vidéo P2P ainsi que des mécanismesd'allocation de bande passante et d'ordonnancement pour le streaming pair-à-pair. Nous nousintéressons également aux techniques d'adaptation de la qualité en se focalisant plusparticulièrement sur la norme SVC (Scalable Video Coding).Le chapitre 3 propose des mécanismes de priorisation pour la planification de streaming P2P multicouches.Nous proposons une heuristique pour résoudre un problème général d'affectationgénéralisé (Generalized Assignment Problem – GAP). La solution présentée est ensuite adaptée aucas du streaming non multicouches. Les résultats issus des simulations montrent que les solutionsproposées donnent de meilleurs résultats que les solutions traditionnelles.Le chapitre 4 décrit un mécanisme d'allocation dynamique de la bande passante pour les réseaux destreaming P2P multicouches qui se base sur l'allocation d'une bande passante aux pairs tout enassurant un minimum de qualité de service à l'ensemble des pairs. Les bonnes performances desmécanismes proposés, qui sont détaillées à travers l'étude du ratio concernant l'utilisation de labande passante ainsi que du niveau de satisfaction des pairs, montrent que ces derniers permettentd'obtenir une utilisation optimale de la bande passante.Le chapitre 5 porte sur le lissage du streaming multicouches dans les réseaux P2P en se basant sur lesmétriques liées à la variation de la fréquence et de l'amplitude. Les mécanismes proposés ont étéimplémentés dans un banc d'essai réel et l'évaluation des performances montrent l'efficacité desmécanismes pour le lissage du streaming.Dans le chapitre 6 (conclusion and perspectives), nous résumons les contributions proposées danscette thèse ainsi qu’une ouverture sur les travaux futures / Recently we witnessed an increasing demand for scalable deployment of real-time multimediastreaming applications over Internet. In this context, Peer-to-Peer (P2P) networks are playing asignificant role for supporting large-scale and robust distribution of multimedia content to end-users.However, due to peers’ dynamicity, heterogeneity of terminals and access networks, the deploymentof real-time video streaming applications over P2P networks arises lot of challenges. Indeed, animportant issue in P2P overlays is the capacity to self-organize in the face of the dynamic behavior ofpeers in order to ensure content availability and continuity. In addition, the heterogeneity in networks,terminals, and P2P characteristics make the situation more challenging. In this context, layered videostreaming in P2P networks has drawn great interest to overcome these challenges, since it can notonly accommodate large numbers of users, but also handle heterogeneity of peers. However, there isstill a lack of comprehensive studies on video data blocks (chunks) scheduling and bandwidthallocation for the smooth playout in layered streaming over P2P networks.The aim of this thesis is to analyze these concerns and to propose an efficient real-time chunksscheduling and bandwidth allocation mechanisms for QoS provisioning of layered streamingapplications over P2P networks. Our contributions in this thesis are threefold. First, we propose ascheduling mechanism for layered P2P streaming. The proposed mechanism relies on a novelscheduling algorithm that enables each peer to select appropriate stream layers, along withappropriate peers to provide them. The presented mechanism makes efficient use of networkresources and provides high system throughput. Second, we propose a bandwidth allocation modelfor P2 layered streaming systems based on auction mechanisms to optimize the allocation of senderpeers’ uploads bandwidth. The upstream peers organize auctions to “sell” theirs items (links’bandwidth) according to bids submitted by the downstream peers taking into consideration the peerspriorities and the requested layers importance. The ultimate goal is to satisfy the quality levelrequirement for each peer, while reducing the overall streaming cost. Finally, we present a smoothingmechanism for layered streaming in P2P networks. The mechanism aims to reduce the number oflayer changes under varying network conditions, and ensure a smooth playout for the end-user.

Orientador: Prof. Dr. Edmarcio Antonio Belati / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2017. / Esta pesquisa propõe uma metodologia baseada no Fluxo de Potência Ótimo Reativo (FPOR), para a operação dos sistemas de transmissão sob emergência usando o mínimo corte de carga em associação com dispositivos Static VAr Compensator (SVC). O SVC é modelado pelo método da susceptância variável e inserido no problema do FPOR. A função multiobjetivo é formada em três partes, perdas de potência ativa, desvio da tensão e cortes de carga. Propõese um procedimento para calcular os valores dos pesos das funções de perdas e desvio da tensão sendo uma das contribuições deste trabalho. A função de mínimo corte de carga foi associada a uma variável que pode ser contínua ou binária, que corta uma porcentagem (contínua) ou a totalidade (binária) da potência da barra candidata, tratando-se assim como problemas de programação não linear (PNL) ou programação não linear inteira mista (PNLIM) respectivamente. O conjunto de barras candidatas ao corte de carga foi formado pelas barras críticas do sistema para cada situação de contingência e foi definido por meio de uma estratégia proposta neste trabalho para identificar as barras mais susceptíveis ao corte de carga. Para o tratamento das variáveis binárias do problema, foi usado o algoritmo Branch &Bound associado com o FPOR. A metodologia foi testada nos sistemas IEEE de 14 e 118 barras modificados para as diferentes situações de contingência simuladas neste trabalho. / This research proposes a methodology based on the Optimal Reactive Power Flow (ORPF) for the operation of the emergency transmission systems using the minimum load shedding in association with Static VAr Compensator (SVC) devices. The SVC was modeled as a variable susceptance and inserted in the ORPF problem. A multi-objective function was formed by three parts, namely, active power losses, voltage deviation and load shedding was device. Propose a procedure to calculate the values of the weights of the loss functions and the voltage deviation, one of the contributions of this research. The minimum load shedding function uses a variable that can be continuous or binary, which turns off a percentage (continuous) or all (binary) loads of candidate power buses, resulting in a Nonlinear Programming Problems (NLP) or Mixed Integer Nonlinear Programming (MINLP) respectively. The critical buses of the system for each contingency formed the candidate set of buses for the load shedding and was defined by a strategy proposed in this research to identify the bus most susceptible to the load shedding. For the treatment of the binary variables of the problem, a Branch & Bound algorithms associated with the ORPF was used. This methodology was tested in the modified IEEE 14 and 118-bus systems for the different contingency situations simulated in this research.

Denna uppsats undersöker värdet av att inkludera hållbarhet och ESG i en due diligence-process inom kontexten för internationella företagsförvärv. Ett konsultperspektiv tillämpades på grund av externa rådgivares vidsträcka erfarenhet och insyn i denna relativt nya process. Analysen har utgått från två kompletterande perspektiv på värdeskapande, Gemensamt värdeskapande och Stakeholder Value Creation Model med rötter inom Intressentmodellen. Genom kvalitativ metod och semi-strukturerade intervjuer med konsulter med hållbarhetsprofil har perspektiv kring värdeskapande i samband med ESG due diligence framkommit. Analysen visar att potential för värdeskapande på längre sikt finns men att det kortsiktiga värdeskapandet är begränsat. Mindre fördelaktiga ESG-resultat hos målföretaget kan översättas till värdeskapande möjligheter. / This essay examines the value of incorporating sustainability and ESG factors in a due diligence process within the context of international acquisitions. A consulting perspective was applied due to external advisors'  extensive experience and insight into this relatively new process. The analysis has been based in two complementary perspectives on value creation, Shared Value Creation, and the Stakeholder Value Creation Model rooted in the Stakeholder Model. Through qualitative methods and semi-structured interviews with consultants specializing in sustainability, perspectives on value creation related to ESG due diligence have emerged. This analysis indicates that there is potential for long-term value creation, but short term value creation is limited. Less favorable ESG outcomes in the target company can be translated into value creation opportunities.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / In the past few years, an evolution has been occurring in test range network topologies. With the proliferation of IP-based networks at the desktop, range officers are seeking ways to extend IP-based networks to the test range, to derive the cost and operational benefits offered with IP technology. This transition is not without its own set of problems. The operational transition from the traditional, ATM-based ranges to IP-based ranges must be addressed. In many cases, it is desired to maintain the ATM range, and add IP capabilities as time and budget permits. The net result is that frequently a mixed protocol network emerges. Terawave Communications has been developing telemetry transport solutions for both ATM and IP-based networks, along with technology to enable convergence of additional services such as video, voice, and data across test ranges. Terawave has developed a solution for various network topologies from ATM-only and IP-only to mixed protocol implementations, which supports end-to-end interworking of telemetry, video, and additional services over mixed protocol networks. In this paper, Terawave will detail the implementation decisions made in the course of application development, and share a framework for enabling seamless intra- and inter- range communication of telemetry and mixed services.