1,019 research outputs found
Trapping and Steering on Lattice Strings: Virtual Slow Waves, Directional and Non-propagating Excitations
Using a lattice string model, a number of peculiar excitation situations
related to non-propagating excitations and non-radiating sources are
demonstrated. External fields can be used to trap excitations locally but also
lead to the ability to steer such excitations dynamically as long as the
steering is slower than the field's wave propagation. I present explicit
constructions of a number of examples, including temporally limited
non-propagating excitations, directional excitation and virtually slowed
propagation. Using these dynamical lattice constructions I demonstrate that
neither persistent temporal oscillation nor static localization are necessary
for non-propagating excitations to occur.Comment: 16 pages, 5 figures, RevTex4, references added, figure captions
improved, to appear in Physical Review
Topological IIR Filters over Simplicial Topologies via Sheaves
Topology offers a means to formally generalize digital filtering methods
based on digital linear translation-invariant (LTI) filters while also, in
principle, incorporating translation-variant and nonlinear methods as well as
studying large scale (global) properties of filter problems. In this letter we
show how the full content of LTI digital filter theory can be incorporated into
the formalism of topological filters as introduced by Robinson. In particular,
we will give the feedback filter construction associated with infinite impulse
responses (IIR). The result allows for direct translation of LTI filters into
topological filters, which are sheaves of finite vector spaces and suitably
constructed linear maps over simplicial topologies.Comment: 5 pages, 3 figures, accepted for publication: IEEE Signal Processing
Letter
Exploiting road traffic data for very short term load forecasting in smart grids
If accurate short term prediction of electricity consumption is available, the Smart Grid infrastructure can rapidly and reliably react to changing conditions. The economic importance of accurate predictions justifies research for more complex forecasting algorithms. This paper proposes road traffic data as a new input dimension that can help improve very short term load forecasting. We explore the dependencies between power demand and road traffic data and evaluate the predictive power of the added dimension compared with other common features, such as historical load and temperature profiles
Hooking up Web Audio to WebGL Typography
Presented at the 2nd Web Audio Conference (WAC), April 4-6, 2016, Atlanta, Georgia.This presentation was presented as part of a poster/demo session on April 5, 2016. Timestamp: 09:41 - 10:31.This demo introduces programmable text rendering that enables temporal typography in web browsers. Textual interaction is seen not only as a dynamic but interactive process facilitating both scripted and live musical expression in various contexts such as audio-visual performance using keyboards and live coding visualization. We transform plain text into a highly audiovisual medium and a musical interface which is visually expressive by transforming textual properties using real-time web audio signal. Technical realization of the concept uses Web Audio API, WebGL and GLSL shaders. We show a number of examples that illustrate instances of the concept in various scenarios ranging from simple textual visualization, live coding environments and interactive writing platform
The effect of cross-boundary management on the trajectory to commonness in biological invasions
The number of alien species introduced and undergoing range expansion in novel environments is steadily increasing, with important consequences for native ecosystems. The efficacy of management planning and decision making to limit such invasions can be improved by understanding how interventions will impact the population dynamics of recently introduced species. To do so, here we expand on a typological framework that enables the classification of populations over time into 10 categories of commonness, and apply it to a spatially discrete metapopulation with heterogeneous abundance across spatial units (patches). We use this framework to assess the effect of cross-boundary management on the capacity of a metapopulation with different demographic and dispersal characteristics, including time lags in population growth, to become common. We demonstrate this framework by simulating a simple theoretical metapopulation model capable of exploring a range of environments, species characteristics, and management actions. Management can vary in the efficacy of propagule interception between patches, and in the synchronisation of the implementation of these measures across patches (i.e. if management is implemented simultaneously across patches). Simulations show that poor interception efficacy that only modestly reduces the number of propagules entering a given spatial unit cannot be compensated for by strong management synchronisation between spatial units. Management synchronisation will nonetheless result in a reduction in rates of spread once a critical threshold of interception efficacy has been met. Finally, time lags in population growth that may result in delayed spread are an important aspect to be considered in management as they can amplify the efficacy of management. Our results demonstrate how a typological framework of categories of commonness can be used to provide practical insights for the management of biological invasions
Empathy: A clue for prosocialty and driver of indirect reciprocity.
Indirect reciprocity has been proposed to explain prosocial behavior among strangers, whereby the prosocial act is returned by a third party. However, what happens if the prosocial act cannot be observed by the third party? Here, we examine whether empathy serves as a clue for prosociality and whether people are more generous toward more empathetic people. In a laboratory study, we measured prosocial behavior as the amount sent in the dictator game and empathy based on the Interpersonal Reactivity Index (IRI). By using an incentivized task, we find that people believe that more empathetic participants send more money in the dictator game. Thus, people see empathy as a clue for prosocial behavior. Furthermore, in a second dictator game, participants indirectly reciprocate by sending more money to more empathetic recipients. Therefore, we suggest that empathy can replace a reputation derived from observable prosocial behavior in triggering indirect reciprocity
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