69,026 research outputs found
Modelling Users, Intentions, and Structure in Spoken Dialog
We outline how utterances in dialogs can be interpreted using a partial first
order logic. We exploit the capability of this logic to talk about the truth
status of formulae to define a notion of coherence between utterances and
explain how this coherence relation can serve for the construction of AND/OR
trees that represent the segmentation of the dialog. In a BDI model we
formalize basic assumptions about dialog and cooperative behaviour of
participants. These assumptions provide a basis for inferring speech acts from
coherence relations between utterances and attitudes of dialog participants.
Speech acts prove to be useful for determining dialog segments defined on the
notion of completing expectations of dialog participants. Finally, we sketch
how explicit segmentation signalled by cue phrases and performatives is covered
by our dialog model.Comment: 17 page
Neuromorphic analogue VLSI
Neuromorphic systems emulate the organization and function of nervous systems. They are usually composed of analogue electronic circuits that are fabricated in the complementary metal-oxide-semiconductor (CMOS) medium using very large-scale integration (VLSI) technology. However, these neuromorphic systems are not another kind of digital computer in which abstract neural networks are simulated symbolically in terms of their mathematical behavior. Instead, they directly embody, in the physics of their CMOS circuits, analogues of the physical processes that underlie the computations of neural systems. The significance of neuromorphic systems is that they offer a method of exploring neural computation in a medium whose physical behavior is analogous to that of biological nervous systems and that operates in real time irrespective of size. The implications of this approach are both scientific and practical. The study of neuromorphic systems provides a bridge between levels of understanding. For example, it provides a link between the physical processes of neurons and their computational significance. In addition, the synthesis of neuromorphic systems transposes our knowledge of neuroscience into practical devices that can interact directly with the real world in the same way that biological nervous systems do
Cooperativity in the enhanced piezoelectric response of polymer nanowires
We provide a detailed insight into piezoelectric energy generation from
arrays of polymer nanofibers. For sake of comparison, we firstly measure
individual poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFe)) fibers
at well-defined levels of compressive stress. Under an applied load of 2 mN,
single nanostructures generate a voltage of 0.45 mV. We show that under the
same load conditions, fibers in dense arrays exhibit a voltage output higher by
about two orders of magnitude. Numerical modelling studies demonstrate that the
enhancement of the piezoelectric response is a general phenomenon associated to
the electromechanical interaction among adjacent fibers, namely a cooperative
effect depending on specific geometrical parameters. This establishes new
design rules for next piezoelectric nano-generators and sensors.Comment: 31 pages, 11 figures, 1 tabl
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