12,354 research outputs found
Joint in-network video rate adaptation and measurement-based admission control: algorithm design and evaluation
The important new revenue opportunities that multimedia services offer to network and service providers come with important management challenges. For providers, it is important to control the video quality that is offered and perceived by the user, typically known as the quality of experience (QoE). Both admission control and scalable video coding techniques can control the QoE by blocking connections or adapting the video rate but influence each other's performance. In this article, we propose an in-network video rate adaptation mechanism that enables a provider to define a policy on how the video rate adaptation should be performed to maximize the provider's objective (e.g., a maximization of revenue or QoE). We discuss the need for a close interaction of the video rate adaptation algorithm with a measurement based admission control system, allowing to effectively orchestrate both algorithms and timely switch from video rate adaptation to the blocking of connections. We propose two different rate adaptation decision algorithms that calculate which videos need to be adapted: an optimal one in terms of the provider's policy and a heuristic based on the utility of each connection. Through an extensive performance evaluation, we show the impact of both algorithms on the rate adaptation, network utilisation and the stability of the video rate adaptation. We show that both algorithms outperform other configurations with at least 10 %. Moreover, we show that the proposed heuristic is about 500 times faster than the optimal algorithm and experiences only a performance drop of approximately 2 %, given the investigated video delivery scenario
A hybrid decision approach for the association problem in heterogeneous networks
The area of networking games has had a growing impact on wireless networks.
This reflects the recognition in the important scaling advantages that the
service providers can benefit from by increasing the autonomy of mobiles in
decision making. This may however result in inefficiencies that are inherent to
equilibria in non-cooperative games. Due to the concern for efficiency,
centralized protocols keep being considered and compared to decentralized ones.
From the point of view of the network architecture, this implies the
co-existence of network-centric and terminal centric radio resource management
schemes. Instead of taking part within the debate among the supporters of each
solution, we propose in this paper hybrid schemes where the wireless users are
assisted in their decisions by the network that broadcasts aggregated load
information. We derive the utilities related to the Quality of Service (QoS)
perceived by the users and develop a Bayesian framework to obtain the
equilibria. Numerical results illustrate the advantages of using our hybrid
game framework in an association problem in a network composed of HSDPA and 3G
LTE systems.Comment: 5 pages, 4 figures, IEEE Infocom, San Diego, USA, March 2010
An agent-based model of product competition: network structure and coexistence under different information regimes
The paper analyzes how the structure of interaction networks affects the diffusion patterns and market shares of different products in case of local network externalities and imperfect information. The diffusion of the different products/technologies in the market is modelled as the result of two (only partly) interrelated dynamics: i) the interaction between idiosyncratic individual thresholds and local network externalities; ii) the diffusion of the information about the product (via broadcast diffusion and word-of-mouth). The average clustering coefficient affects the overall outcome and the actual possibility that one product corners the market. Moreover, in case of small-world networks, despite the high clustering coefficient which increases the probability of an outcome with coexistence, the increase in the speed of diffusion impinges on the actual realization of such an outcome in case of sequential entry of the different technologies and/or imperfect information.Agent-based model, innovation diusion, network eects,social networks, small-world
Generalized Multivariate Extreme Value Models for Explicit Route Choice Sets
This paper analyses a class of route choice models with closed-form
probability expressions, namely, Generalized Multivariate Extreme Value (GMEV)
models. A large group of these models emerge from different utility formulas
that combine systematic utility and random error terms. Twelve models are
captured in a single discrete choice framework. The additive utility formula
leads to the known logit family, being multinomial, path-size, paired
combinatorial and link-nested. For the multiplicative formulation only the
multinomial and path-size weibit models have been identified; this study also
identifies the paired combinatorial and link-nested variations, and generalizes
the path-size variant. Furthermore, a new traveller's decision rule based on
the multiplicative utility formula with a reference route is presented. Here
the traveller chooses exclusively based on the differences between routes. This
leads to four new GMEV models. We assess the models qualitatively based on a
generic structure of route utility with random foreseen travel times, for which
we empirically identify that the variance of utility should be different from
thus far assumed for multinomial probit and logit-kernel models. The expected
travellers' behaviour and model-behaviour under simple network changes are
analysed. Furthermore, all models are estimated and validated on an
illustrative network example with long distance and short distance
origin-destination pairs. The new multiplicative models based on differences
outperform the additive models in both tests
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