121,746 research outputs found
The Effects of Technology and Innovation on Society
Various models of the information society have been
developed so far and they are so different from country to
country that it would be rather unwise to look for a single, allencompassing definition. In our time a number of profound
socio-economic changes are underway. The application of these
theories and schools on ICT is problematic in many respects.
First, as we stated above, there is not a single, widely used
paradigm which has synthesised the various schools and theories
dealing with technology and society. Second, these fragmented
approaches do not have a fully-fledged mode of application to the relationship of ICT and (information) society. Third, SCOT,
ANT, the evolutionary- or the systems approach to the history of technology when dealing with information society – does not take into account the results of approaches studying the very essence of the information age: information, communication and
knowledge. The list of unnoticed or partially incorporated
sciences, which focuses on the role of ICT in human information
processing and other cognitive activities, is much longer
Effects of communication efficiency and exit capacity on fundamental diagrams for pedestrian motion in an obscure tunnel|a particle system approach
Fundamental diagrams describing the relation between pedestrians speed
and density are key points in understanding pedestrian dynamics.
Experimental data evidence the onset of complex behaviors in which the
velocity decreases with the density and different logistic regimes are
identified. This paper addresses the issue of pedestrians transport and of fundamental diagrams for a scenario involving the motion of pedestrians
escaping from an obscure tunnel.
% via a simple one--dimensional particle system model.
We capture the effects of the communication efficiency and
the exit capacity by means of two thresholds controlling the rate
at which particles (walkers, pedestrians) move on the lattice.
Using a particle system model, we show that in absence of limitation in communication among
pedestrians we reproduce
with good accuracy the standard fundamental diagrams, whose
basic behaviors can be interpreted in terms of the exit capacity
limitation.
When the effect of a limited communication ability is considered, then
interesting non--intuitive phenomena occur. Particularly, we shed light on
the loss of monotonicity of the typical speed--density curves,
revealing the existence of a
pedestrians density optimizing the escape.
We study both the discrete particle dynamics as well as the corresponding hydrodynamic limit (a porous medium equation and a transport (continuity) equation). We also point out the dependence of the effective transport coefficients on the two thresholds -- the essence of the microstructure information
Challenges of digital innovations : a set-top box based approach
The chapter analyses the challenges of digital technology for television audience measurement systems. First, the current state of audience measurement in Belgium is described. In the Belgian case, the traditional television audience measurement system is contested by small broadcasters and challenged by the opportunities that the emergence of digital television and, more specifically, the widespread diffusion of set-top boxes provide. Second, three major challenges for traditional measurement techniques are analysed. This section deals with people’s changing viewing habits, for example on-demand and time-shifted viewing, the provision of more accurate data by set-top boxes, and the increasing interests of platform operators acting as gatekeepers to access to this data. In the final section, conclusions are made
Coping with creeping catastrophes: national political systems and the challenge of slow-moving policy problems
No abstract available
Flow Level QoE of Video Streaming in Wireless Networks
The Quality of Experience (QoE) of streaming service is often degraded by
frequent playback interruptions. To mitigate the interruptions, the media
player prefetches streaming contents before starting playback, at a cost of
delay. We study the QoE of streaming from the perspective of flow dynamics.
First, a framework is developed for QoE when streaming users join the network
randomly and leave after downloading completion. We compute the distribution of
prefetching delay using partial differential equations (PDEs), and the
probability generating function of playout buffer starvations using ordinary
differential equations (ODEs) for CBR streaming. Second, we extend our
framework to characterize the throughput variation caused by opportunistic
scheduling at the base station, and the playback variation of VBR streaming.
Our study reveals that the flow dynamics is the fundamental reason of playback
starvation. The QoE of streaming service is dominated by the first moments such
as the average throughput of opportunistic scheduling and the mean playback
rate. While the variances of throughput and playback rate have very limited
impact on starvation behavior.Comment: 14 page
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