848 research outputs found
Planning and dynamic spectrum management in heterogeneous mobile networks with QoE optimization
The radio and network planning and optimisation are continuous processes that do not end after the network has been launched. To achieve the best trade-offs, especially between quality and costs, operators make use of several coverage and capacity enhancement methods. The research from this thesis proposes methods such as the implementation of cell zooming and Relay Stations (RSs) with dynamic sleep modes and Carrier Aggregation (CA) for coverage and capacity enhancements.
Initially, a survey is presented on ubiquitous mesh networks implementation scenarios and an updated characterization of requirements for services and applications is proposed. The performance targets for the key parameters, delay, delay variation, information loss and throughput have been addressed for all types of services. Furthermore, with the increased competition, mobile operatorâs success does not only depend on how good the offered Quality of Service (QoS) is, but also if it meets the end userâs expectations, i.e., Quality of Experience (QoE). In this context, a model for the mapping between QoS parameters and QoE has been proposed for multimedia traffic.
The planning and optimization of fixed Worldwide Interoperability for Microwave Access (WiMAX) networks with RSs in conjunction with cell zooming has been addressed. The challenging case of a propagation measurement-based scenario in the hilly region of CovilhĂŁ has been considered. A cost/revenue function has been developed by taking into account the cost of building and maintaining the infrastructure with the use of RSs. This part of the work also investigates the energy efficiency and economic implications of the use of power saving modes for RSs in conjunction with cell zooming. Assuming that the RSs can be switched-off or zoomed out to zero in periods when the trafïŹc exchange is low, such as nights and weekends, it has been shown that energy consumption may be reduced whereas cellular coverage and capacity, as well as economic performance may be improved.
An integrated Common Radio Resource Management (iCRRM) entity is proposed that implements inter-band CA by performing scheduling between two Long Term Evolution â Advanced (LTE-A) Component Carriers (CCs). Considering the bandwidths available in Portugal, the 800 MHz and 2.6 GHz CCs have been considered whilst mobile video traffic is addressed. Through extensive simulations it has been found that the proposed multi-band schedulers overcome the capacity of LTE systems without CA. Result shown a clear improvement of the QoS, QoE and economic trade-off with CA
Context-adaptive information flow allocation and media delivery in online social networks
This paper investigates context-driven flow allocation and media delivery in online social networks. We exploit information on contacts and content preferences found in social networking applications to provide efficient network services and operation at the underlying transport layer. We formulate a linear programming framework that maximizes the information flow-cost ratio of the transport network serving the nodes in the social graph. For practical deployments, we also design a distributed version of the optimization framework that provides similar performance to its centralized counterpart, with lower complexity. In addition, we devise a tracker-based system for efficient content discovery in peer-to-peer (P2P) systems based on social network information. Finally, we design a context-aware packet scheduling technique that maximizes the utility of media delivery among the members of the social network. We provide a comprehensive investigation of the performance of our optimization strategies through both simulations and analysis. We demonstrate their significant advantages over several performance factors relative to conventional solutions that do not employ social network information in their operation
Entropy-Based Dynamic Ad Placement Algorithms for In-Video Advertising
With the evolution of the Internet and the increasing number of users over last years, online
advertising has become one of the pillars models that sustains many of the Internet businesses.
In this dissertation, we review the history of online advertising, will be made, as well as the
state-of-the-art of the major scientific contributions in online advertising,in particularly in
respect to in-video advertising.
In in-video advertising, one of the major issues is to identify the best places for insertion of
ads. In the literature, this problem is addressed in different ways. Some methods are designed
for a specific genres of video, e.g., football or tennis, while others are independent of genre,
trying to identify the meaningful video scenes (a set of continuous and related frames) where
ads will be displayed.
However, the vast majority of online videos in the Internet are not long enough to identify
large scenes. So, in this dissertation we will address a new solution for advertisement insertion
in online videos, a solution that can be utilized independently of the duration and genre of the
video in question.
When developing a solution for in-video advertising, a major challenge rests on the intrusiveness
that the ad inserted will take upon the viewer. The intrusiveness is related to the place and
timing used by the advertising to be inserted. For these reasons, the algorithm has to take in
consideration the "where", "when" and "how" the advertisement should be inserted in the video,
so that it is possible to reduce the intrusiveness of the ads to the viewer.
In short, in addition to besides being independent of duration and genre, the proposed method
for ad placement in video was developed taking in consideration the ad intrusiveness to the
user.Com a evolução da Internet e o nĂșmero crescente de utilizadores ao longo destes Ășltimos anos,
a publicidade on-line tornou-se um dos modelos base que tem sustentado muitos negĂłcios na
Internet. Da mesma forma, vĂdeos on-line constituem uma parte significativa do trĂĄfego na
Internet. Ă por isso possĂvel entender desta forma, o potencial que ferramentas que possĂŁo
explorar eficientemente ambas estas ĂĄreas possuem no mercado.
Nesta dissertação serå feita uma revisão da história da publicidade online, mas também serå
apresentado ao leitor uma revisĂŁo sobre o estado da arte das principais contribuiçÔes cientĂficas
para a publicidade on-line, em especial para a publicidade em video.
Na publicidade em vĂdeo, uma das principais preocupaçÔes Ă© identificar os melhores locais para
a inserir os anĂșncios. Na literatura, este problema Ă© abordado de diferentes maneiras, alguns
criaram mĂ©todos para gĂȘneros especĂficos de vĂdeo, por exemplo, futebol ou tĂ©nis, outros
mĂ©todos sĂŁo independentes do gĂȘnero, mas tentam identificar as cenas de vĂdeo (um conjunto
contĂnuo de frames relacionadas) e apenas exibir anĂșncios neles.
No entanto, a grande maioria dos vĂdeos on-line na Internet nĂŁo sĂŁo suficiente longos para serem
identificadas cenas suficientemente longas para inserir os anĂșncios. Assim, nesta dissertação
iremos abordar uma nova solução para a inserção de anĂșnicios em vĂdeos, uma solução que
pode ser utilizada de forma independente da duração e gĂȘnero do vĂdeo em questĂŁo.
Ao desenvolver uma solução para inserir anĂșncos em vĂdeos a grande preocupação recai sobre
a intromissĂŁo que o anĂșncio inserido poderĂĄ ter sobre o utilizador. A intrusĂŁo estĂĄ relacionada
com o local e tempo utilizado pela publicidade quando é inserida. Por estas razÔes, o algoritmo
tem que levar em consideração "onde", "quando" e "como" o anĂșncio deve ser inserido no vĂdeo,
de modo que seja possĂvel reduzir a intromissĂŁo dos anĂșncios para o utilizador.
Em suma, para alĂ©m de ser independente da duração e gĂȘnero do vĂdeo, o mĂ©todo proposto
serĂĄ tambĂ©m desenvolvido tendo em consideração a intromissĂĄo do anĂșncio para o utilizador.
Por fim, o método proposto serå testado e comparado com outros métodos, de modo a que seja
possivel perceber as suas capacidades
Heterogeneous Networks for the IoT and Machine Type Communications
The Internet of Things promises to be a key-factor in the forthcoming industrial and social revolution. The Internet of Things concept rely on pervasive communications where âthingsâ are âalways connectedâ. The focus of the thesis is on Heterogeneous Networks for Internet of Things and Machine Type Communications. Heterogeneous Networks are an enabling factor of paramount important in order to achieve the âalways connectedâ paradigm. On the other hand, Machine Type Communications are deeply different from Human-to-Human communications both in terms of traffic patterns and requirements. This thesis investigate both concepts. In particular, here are studied short and long range solutions for Machine-to-machine applications. For this work a dual approach has been followed: for the short-range solutions analysis an experimental approach has been privileged; meanwhile for the long-range solutions analysis a theoretical and simulation approach has been preferred. In both case, a particular attention has been given to the feasibility of the solutions proposed, hence solutions based on products that already exist in the market have been privileged
Serviços multimédia multicast de próxima geração
Mestrado em Engenharia ElectrĂłnica e TelecomunicaçÔesUma das mais recentes conquistas na evolução mĂłvel foi o 3G, permitindo o acesso a serviços multimĂ©dia com qualidade de serviço assegurada. No entanto, a tecnologia UMTS, tal como definida na sua Release â99, Ă© apenas capaz de transmitir em modo unicast, sendo manifestamente ineficiente para comunicaçÔes multimĂ©dia almejando grupos de utilizadores.
A tecnologia IMS surge na Release 5 do 3GPP que começou a responder jĂĄ a algumas necessidades, permitindo comunicaçÔes sobre IP oferecendo serviços Internet a qualquer momento e em qualquer lugar sobre tecnologias de comunicação mĂłveis fornecendo pela primeira vez sessĂ”es multimĂ©dia satisfatĂłrias. A Release 6 por sua vez trouxe a tecnologia MBMS que permite transmissĂ”es em broadcast e multicast para redes mĂłveis. O MBMS fornece os serviços de aplicaçÔes multimĂ©dia que todos estavam Ă espera, tanto para os utilizadores como para os prestadores de serviços. O operador pode agora fazer uso da tecnologia existente aumentando todo o tipo de benefĂcios no serviço prestado ao cliente. Com a possĂvel integração destas duas tecnologias passa a ser possĂvel desenvolver serviços assentes em redes convergentes em que os conteĂșdos sĂŁo entregues usando tecnologias unicast, multicast ou broadcast. Neste contexto, o principal motivo deste trabalho consiste essencialmente em fazer uso dos recursos da rede terminando com o desperdĂcio dos mesmos e aumentando a eficiĂȘncia dos serviços atravĂ©s da integração das tecnologias IMS e MBMS.
O trabalho realizado começa com o estudo do estado da arte das telecomunicaçÔes mĂłveis com referĂȘncia Ă s tecnologias referidas, seguindo-se a apresentação da possĂvel integração IMS-MBMS e terminando com o projecto de uma plataforma de demonstração que no futuro possa ser uma implementação de serviço multimĂ©dia multicast. O objectivo principal Ă© mostrar os benefĂcios de um serviço que era normalmente executado em unicast relativamente ao modo multicast, fazendo uso da nova convergĂȘncia de tecnologias IMS e MBMS. Na conclusĂŁo do trabalho sĂŁo referidas as vantagens do uso de portadoras multicast e broadcast, tendo como perspectiva de que este trabalho possa ser um ponto de partida para um novo conjunto de serviços poupando recursos de rede e permitindo uma eficiĂȘncia considerĂĄvel em serviços inovadores.3G is bang up to date in the mobile phone industry. It allows access to multimedia services and gives a guarantee of quality of service. The UMTS technology, defined in 3GPP Release â99, provides an unicast transmission, but it is completely inefficient when it comes to multimedia group communications.
The IMS technology first appeared in Release 5 that has already started to consider the interests of the clients. It provides communications over IP, offering Internet services anytime, anywhere on mobile communication technologies. Also, it offers for the first time satisfactory multimedia sessions. On the other hand, Release 6 gave rise to the MBMS technology that provides broadcast and multicast transmissions for mobile networks. The MBMS provides multimedia applications services that everyone was waiting, including users and service providers. Now the operator makes use of existing technology in order to provide better costumer services. The possible integration of these two technologies will contribute to develop services based on converged networks in which contents are delivered through the unicast, multicast or broadcast technologies. Therefore, the objective of this work is basically to make use of network resources avoiding wastes and improving customer services through the integration of the IMS and the MBMS technologies.
The executed work starts with the mobile telecommunications state of the art with reference to the referred technologies, followed by the IMS-MBMS convergence presentation and finishing with the proposal for implementation of a service platform that can be used for a multimedia multicast service. The main point is to show the benefits of a service that has been normally executed in unicast mode over the multicast mode, making use of the new IMS and MBMS technologies integration. To closure the work it is referred the advantages to use multicast and broadcast bearers, with the perspective that this work could be a starting point to a new set of services, saving network resources and allowing for innovate services a considerable efficency
An Economic Framework For Resource Management And Pricing In Wireless Networks With Competitive Service Providers
A paradigm shift from static spectrum allocation to dynamic spectrum access (DSA) is becoming a reality due to the recent advances in cognitive radio, wide band spectrum sensing, and network aware real--time spectrum access. It is believed that DSA will allow wireless service providers (WSPs) the opportunity to dynamically access spectrum bands as and when they need it. Moreover, due to the presence of multiple WSPs in a region, it is anticipated that dynamic service pricing would be offered that will allow the end-users to move from long-term service contracts to more flexible short-term service models. In this research, we develop a unified economic framework to analyze the trading system comprising two components: i) spectrum owner--WSPs interactions with regard to dynamic spectrum allocation, and ii) WSP--end-users interactions with regard to dynamic service pricing. For spectrum owner--WSPs interaction, we investigate various auction mechanisms for finding bidding strategies of WSPs and revenue generated by the spectrum owner. We show that sequential bidding provides better result than the concurrent bidding when WSPs are constrained to at most single unit allocation. On the other hand, when the bidders request for multiple units, (i.e., they are not restricted by allocation constraints) synchronous auction mechanism proves to be beneficial than asynchronous auctions. In this regard, we propose a winner determination sealed-bid knapsack auction mechanism that dynamically allocates spectrum to the WSPs based on their bids. As far as dynamic service pricing is concerned, we use game theory to capture the conflict of interest between WSPs and end--users, both of whom try to maximize their respective net utilities. We deviate from the traditional per--service static pricing towards a more dynamic model where the WSPs might change the price of a service almost on a session by session basis. Users, on the other hand, have the freedom to choose their WSP based on the price offered. It is found that in such a greedy and non-cooperative behavioral game model, it is in the best interest of the WSPs to adhere to a price threshold which is a consequence of a price (Nash) equilibrium. We conducted extensive simulation experiments, the results of which show that the proposed auction model entices WSPs to participate in the auction, makes optimal use of the common spectrum pool, and avoids collusion among WSPs. We also demonstrate how pricing can be used as an effective tool for providing incentives to the WSPs to upgrade their network resources and offer better services
CHORUS Deliverable 2.1: State of the Art on Multimedia Search Engines
Based on the information provided by European projects and national initiatives related to multimedia search as well as domains experts that participated in the CHORUS Think-thanks and workshops, this document reports on the state of the art related to multimedia content search from, a technical, and socio-economic perspective.
The technical perspective includes an up to date view on content based indexing and retrieval technologies, multimedia search in the context of mobile devices and peer-to-peer networks, and an overview of current evaluation and benchmark inititiatives to measure the performance of multimedia search engines.
From a socio-economic perspective we inventorize the impact and legal consequences of these technical advances and point out future directions of research
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