8,071 research outputs found
Fine-grained traffic state estimation and visualisation
Tools for visualising the current traffic state are used by local authorities for strategic monitoring of the traffic network and by everyday users for planning their journey. Popular visualisations include those provided by Google Maps and by Inrix. Both employ a traffic lights colour-coding system, where roads on a map are coloured green if traffic is flowing normally and red or black if there is congestion. New sensor technology, especially from wireless sources, is allowing resolution down to lane level. A case study is reported in which a traffic micro-simulation test bed is used to generate high-resolution estimates. An interactive visualisation of the fine-grained traffic state is presented. The visualisation is demonstrated using Google Earth and affords the user a detailed three-dimensional view of the traffic state down to lane level in real time
Topological code Autotune
Many quantum systems are being investigated in the hope of building a
large-scale quantum computer. All of these systems suffer from decoherence,
resulting in errors during the execution of quantum gates. Quantum error
correction enables reliable quantum computation given unreliable hardware.
Unoptimized topological quantum error correction (TQEC), while still effective,
performs very suboptimally, especially at low error rates. Hand optimizing the
classical processing associated with a TQEC scheme for a specific system to
achieve better error tolerance can be extremely laborious. We describe a tool
Autotune capable of performing this optimization automatically, and give two
highly distinct examples of its use and extreme outperformance of unoptimized
TQEC. Autotune is designed to facilitate the precise study of real hardware
running TQEC with every quantum gate having a realistic, physics-based error
model.Comment: 13 pages, 17 figures, version accepted for publicatio
Piloting mobile mixed reality simulation in paramedic distance education
New pedagogical methods delivered through mobile mixed reality (via a user-supplied mobile phone incorporating 3d printing and augmented reality) are becoming possible in distance education, shifting pedagogy from 2D images, words and videos to interactive simulations and immersive mobile skill training environments. This paper presents insights from the implementation and testing of a mobile mixed reality intervention in an Australian distance paramedic science classroom. The context of this mobile simulation study is skills acquisition in airways management focusing on direct laryngoscopy with foreign body removal. The intervention aims to assist distance education learners in practicing skills prior to attending mandatory residential schools and helps build a baseline equality between those students that study face to face and those at a distance. Outcomes from the pilot study showed improvements in several key performance indicators in the distance learners, but also demonstrated problems to overcome in the pedagogical method
Stacking designs: designing multi-fidelity experiments with target predictive accuracy
In an era where scientific experiments can be very costly, multi-fidelity
emulators provide a useful tool for cost-efficient predictive scientific
computing. For scientific applications, the experimenter is often limited by a
tight computational budget, and thus wishes to (i) maximize predictive power of
the multi-fidelity emulator via a careful design of experiments, and (ii)
ensure this model achieves a desired error tolerance with some notion of
confidence. Existing design methods, however, do not jointly tackle objectives
(i) and (ii). We propose a novel stacking design approach that addresses both
goals. Using a recently proposed multi-level Gaussian process emulator model,
our stacking design provides a sequential approach for designing multi-fidelity
runs such that a desired prediction error of is met under
regularity assumptions. We then prove a novel cost complexity theorem that,
under this multi-level Gaussian process emulator, establishes a bound on the
computation cost (for training data simulation) needed to achieve a prediction
bound of . This result provides novel insights on conditions under
which the proposed multi-fidelity approach improves upon a standard Gaussian
process emulator which relies on a single fidelity level. Finally, we
demonstrate the effectiveness of stacking designs in a suite of simulation
experiments and an application to finite element analysis
Domain-wall melting in ultracold boson systems with holes and spin-flip defects
Quantum magnetism is a fundamental phenomenon of nature. As of late, it has
garnered a lot of interest because experiments with ultracold atomic gases in
optical lattices could be used as a simulator for phenomena of magnetic
systems. A paradigmatic example is the time evolution of a domain-wall state of
a spin-1/2 Heisenberg chain, the so-called domain-wall melting. The model can
be implemented by having two species of bosonic atoms with unity filling and
strong on-site repulsion U in an optical lattice. In this paper, we study the
domain-wall melting in such a setup on the basis of the time-dependent density
matrix renormalization group (tDMRG). We are particularly interested in the
effects of defects that originate from an imperfect preparation of the initial
state. Typical defects are holes (empty sites) and flipped spins. We show that
the dominating effects of holes on observables like the spatially resolved
magnetization can be taken account of by a linear combination of spatially
shifted observables from the clean case. For sufficiently large U, further
effects due to holes become negligible. In contrast, the effects of spin flips
are more severe as their dynamics occur on the same time scale as that of the
domain-wall melting itself. It is hence advisable to avoid preparation schemes
that are based on spin-flips.Comment: 15 pages, 12 figures. Supplemental Material: 2 animations (avi)
comparing the domain-wall melting with and without defects, corresponding to
figures 3, 4 and the discussion in section V.B; minor improvements; published
versio
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