8,474 research outputs found
Monte Carlo analysis of inaccuracies in estimated aircraft parameters caused by unmodeled flight instrumentation errors
An output error estimation algorithm was used to evaluate the effects of both static and dynamic instrumentation errors on the estimation of aircraft stability and control parameters. A Monte Carlo error analysis, using simulated cruise flight data, was performed for a high-performance military aircraft, a large commercial transport, and a small general aviation aircraft. The results indicate that unmodeled instrumentation errors can cause inaccuracies in the estimated parameters which are comparable to their nominal values. However, the corresponding perturbations to the estimated output response trajectories and characteristics equation pole locations appear to be relatively small. Control input errors and dynamic lags were found to be in the most significant of the error sources evaluated
Documentation of procedures for textural/spatial pattern recognition techniques
A C-130 aircraft was flown over the Sam Houston National Forest on March 21, 1973 at 10,000 feet altitude to collect multispectral scanner (MSS) data. Existing textural and spatial automatic processing techniques were used to classify the MSS imagery into specified timber categories. Several classification experiments were performed on this data using features selected from the spectral bands and a textural transform band. The results indicate that (1) spatial post-processing a classified image can cut the classification error to 1/2 or 1/3 of its initial value, (2) spatial post-processing the classified image using combined spectral and textural features produces a resulting image with less error than post-processing a classified image using only spectral features and (3) classification without spatial post processing using the combined spectral textural features tends to produce about the same error rate as a classification without spatial post processing using only spectral features
Therapeutic outcomes in a museum? âYou don't get them by aiming for themâ. How a focus on arts participation promotes inclusion and well-being
Background: The three year âWays of Seeingâ project was hosted by an award-winning museum and included adults with long-term diagnoses associated with mental health and physical impairments. The participants were involved throughout the project, preparing and curating artwork for a major public exhibition. Methods: Qualitative data were collected to explore meanings of the project from the perspective of participants, the project manager and the public, using interviews, participant observation and comment cards. Results: The project was successful in engaging the participants who had previously often felt excluded from mainstream art spaces. Findings about the benefits of arts participation echoed other studies but participants highlighted some difficulty with the ending of the project. Public perceptions were positive, acclaiming the thought-provoking quality of the exhibition. Interviews and participant observation revealed the importance of egalitarian leadership, mutual trust and the absence of any therapeutic agenda. Conclusion: Developing similar projects would offer opportunities to foster diverse artistic communities and empower people with experiences of disability and mental health conditions
Dynamics of hard-sphere suspension using Dynamic Light Scattering and X-Ray Photon Correlation Spectroscopy: dynamics and scaling of the Intermediate Scattering Function
Intermediate Scattering Functions (ISF's) are measured for colloidal hard
sphere systems using both Dynamic Light Scattering (DLS) and X-ray Photon
Correlation Spectroscopy (XPCS). We compare the techniques, and discuss the
advantages and disadvantages of each. Both techniques agree in the overlapping
range of scattering vectors. We investigate the scaling behaviour found by
Segre and Pusey [1] but challenged by Lurio et al. [2]. We observe a scaling
behaviour over several decades in time but not in the long time regime.
Moreover, we do not observe long time diffusive regimes at scattering vectors
away from the peak of the structure factor and so question the existence of a
long time diffusion coefficients at these scattering vectors.Comment: 21 pages, 11 figure
PP-waves with torsion and metric-affine gravity
A classical pp-wave is a 4-dimensional Lorentzian spacetime which admits a
nonvanishing parallel spinor field; here the connection is assumed to be
Levi-Civita. We generalise this definition to metric compatible spacetimes with
torsion and describe basic properties of such spacetimes. We use our
generalised pp-waves for constructing new explicit vacuum solutions of
quadratic metric-affine gravity.Comment: 17 pages, LaTeX2
Incorporation of random alloy GaBiAs barriers in InAs quantum dot molecules: alloy strain and orbital effects towards enhanced tunneling
Self-assembled InAs quantum dots (QDs), which have long hole-spin coherence
times and are amenable to optical control schemes, have long been explored as
building blocks for qubit architectures. One such design consists of vertically
stacking two QDs to create a quantum dot molecule (QDM). The two dots can be
resonantly tuned to form "molecule-like" coupled hole states from the
hybridization of hole states otherwise localized in each respective dot.
Furthermore, spin-mixing of the hybridized states in dots offset along their
stacking direction enables qubit rotation to be driven optically, allowing for
an all-optical qubit control scheme. Increasing the magnitude of this spin
mixing is important for optical quantum control protocols. To enhance the
tunnel coupling and spin-mixing across the dots, we introduce Bi in the GaAs
inter-dot barrier. Previously, we showed how to model InAs/GaBiAs in an
atomistic tight-binding formalism, and how the dot energy levels are affected
by the alloy. In this paper, we discuss the lowering of the tunnel barrier,
which results in a three fold increase of hole tunnel coupling strength in the
presence of a 7% alloy. Additionally, we show how an asymmetric strain between
the two dots caused by the alloy shifts the resonance. Finally, we discuss
device geometries for which the introduction of Bi is most advantageous.Comment: RevTex 4-2, 11 pages, 9 figure
HumanâBlack Bear Conflicts: A Review of Common Management Practices
The objective of this monograph is to provide wildlife professionals, who respond to humanâbear conflicts, with an appraisal of the most common techniques used for mitigating conflicts as well as the benefits and challenges of each technique in a single document. Most humanâblack bear conflict occurs when people make anthropogenic foods like garbage, dog food, domestic poultry, or fruit trees available to bears. Bears change their behavior to take advantage of these resources and may damage property or cause public safety concerns in the process. Managers and the public need to understand the available tools to stop humanâbear conflict and reduce effects on bear populations.https://digitalcommons.usu.edu/hwi_monographs/1002/thumbnail.jp
Multiband theory of quantum-dot quantum wells: Dark excitons, bright excitons, and charge separation in heteronanostructures
Electron, hole, and exciton states of multishell CdS/HgS/CdS quantum-dot
quantum well nanocrystals are determined by use of a multiband theory that
includes valence-band mixing, modeled with a 6-band Luttinger-Kohn Hamiltonian,
and nonparabolicity of the conduction band. The multiband theory correctly
describes the recently observed dark-exciton ground state and the lowest,
optically active, bright-exciton states. Charge separation in pair states is
identified. Previous single-band theories could not describe these states or
account for charge separation.Comment: 10 pages of ReVTex, 6 ps figures, submitted to Phys. Rev.
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