414 research outputs found
Can cooperation slow down emergency evacuations?
We study the motion of pedestrians through obscure corridors where the lack
of visibility hides the precise position of the exits. Using a lattice model,
we explore the effects of cooperation on the overall exit flux (evacuation
rate). More precisely, we study the effect of the buddying threshold (of
no--exclusion per site) on the dynamics of the crowd. In some cases, we note
that if the evacuees tend to cooperate and act altruistically, then their
collective action tends to favor the occurrence of disasters.Comment: arXiv admin note: text overlap with arXiv:1203.485
Region of interest-based adaptive multimedia streaming scheme
Adaptive multimedia streaming aims at adjusting
the transmitted content based on the available bandwidth such as losses that often severely affect the end-user perceived quality are minimized and consequently the transmission quality increases. Current solutions affect equally the whole viewing area of the multimedia frames, despite research showing that there are regions on which the viewers are more interested in than on others. This paper presents a novel region of interest-based adaptive scheme (ROIAS) for multimedia streaming that when performing transmission-related quality adjustments, selectively affects the quality of those regions of the image the viewers are the least interested in. As the quality of the regions the viewers are the most interested in will not change (or will involve little change),the proposed scheme provides higher overall end-user perceived
quality than any of the existing adaptive solutions
Stationary currents in particle systems with constrained hopping rates
We study the effect on the stationary currents of constraints affecting the
hopping rates in stochastic particle systems. In the framework of Zero Range
Processes with drift within a finite volume, we discuss how the current is
reduced by the presence of the constraint and deduce exact formulae, fully
explicit in some cases. The model discussed here has been introduced in Ref.
[1] and is relevant for the description of pedestrian motion in elongated dark
corridors, where the constraint on the hopping rates can be related to
limitations on the interaction distance among pedestrians
Does communication enhance pedestrians transport in the dark?
We study the motion of pedestrians through an obscure tunnel where the lack
of visibility hides the exits. Using a lattice model, we explore the effects of
communication on the effective transport properties of the crowd of
pedestrians. More precisely, we study the effect of two thresholds on the
structure of the effective nonlinear diffusion coefficient. One threshold
models pedestrians's communication efficiency in the dark, while the other one
describes the tunnel capacity. Essentially, we note that if the evacuees show a
maximum trust (leading to a fast communication), they tend to quickly find the
exit and hence the collective action tends to prevent the occurrence of
disasters
A Continuum Model for Morphology Formation from Interacting Ternary Mixtures: Simulation Study of the Formation and Growth of Patterns
Our interest lies in exploring the ability of a coupled nonlocal system of
two quasilinear parabolic partial differential equations to produce phase
separation patterns. The obtained patterns are referred here as morphologies.
Our target system is derived in the literature as the rigorous hydrodynamic
limit of a suitably scaled interacting particle system of Blume--Capel--type
driven by Kawasaki dynamics. The system describes in a rather implicit way the
interaction within a ternary mixture that is the macroscopic counterpart of a
mix of two populations of interacting solutes in the presence of a background
solvent. Our discussion is based on the qualitative behavior of numerical
simulations of finite volume approximations of smooth solutions to our system
and their quantitative postprocessing in terms of two indicators (correlation
and structure factor calculations). Our results show many similar features
compared to what one knows at the level of the stochastic Blume--Capel dynamics
with three interacting species. The properties of the obtained morphologies
(shape, connectivity, and so on) can play a key role in, e.g., the design of
the active layer for efficient organic solar cells
Anticipation decides on lane formation in pedestrian counterflow -- a simulation study
Human crowds base most of their behavioral decisions upon anticipated states
of their walking environment. We explore a minimal version of a lattice model
to study lanes formation in pedestrian counterflow. Using the concept of
horizon depth, our simulation results suggest that the anticipation effect
together with the presence of a small background noise play an important role
in promoting collective behaviors in a counterflow setup. These ingredients
facilitate the formation of seemingly stable lanes and ensure the ergodicity of
the system
Audio masking effect on inter-component skews in olfaction-enhanced multimedia presentations
Media-rich content plays a vital role in consumer applications today, as these applications try to find new and interesting ways to engage their users. Video, audio, and the more traditional forms of media content continue to dominate with respect to the use of media content to enhance the user experience. Tactile interactivity has also now become widely popular in modern computing applications, while our olfactory and gustatory senses continue to have a limited role. However, in recent times, there have been significant advancements regarding the use of olfactory media content (i.e., smell), and there are a variety of devices now available to enable its computer-controlled emission. This paper explores the impact of the audio stream on user perception of olfactory-enhanced video content in the presence of skews between the olfactory and video media. This research uses the results from two experimental studies of user-perceived quality of olfactory-enhanced multimedia, where audio was present and absent, respectively. Specifically, the paper shows that the user Quality of Experience (QoE) is generally higher in the absence of audio for nearly perfect synchronized olfactory-enhanced multimedia presentations (i.e., an olfactory media skew of between {−10,+10s}); however, for greater olfactory media skews (ranging between {−30s;−10s} and {+10s, +30s}) user QoE is higher when the audio stream is present. It can be concluded that the presence of the audio has the ability to mask larger synchronization skews between the other media components in olfaction-enhanced multimedia presentations
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