330 research outputs found
Amodel of the Microclimate in Porous Shade Houses
The first shade-house microclimatic model was developed based on the energy and moisture balances of four shade-house system components - the shade cloth, inside air, canopy, and soil surface. The transport is parameterized by resistances for small-scale turbulence and by intermittent refreshment for large-scale non-local gusts. The temperature and humidity in a semi-infinite shade house are predicted when the six coupled differential equations based on the energy and moisture balances are simultaneously solved. The model includes liquid-water balances for surfaces. The model requires only weather data, and, if desired, measured shade-house characterization data. Weather data for running the model, inside temperature and humidity data for verifying the model, and energy balance and turbulence data for further development of the model processes were collected in a large commercial shade house near Pahoa, Hawaii from 10 January to 25 March 1992
Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases
We present a theoretical study of the ground state of the BCS-BEC crossover
in dilute two-dimensional Fermi gases. While the mean-field theory provides a
simple and analytical equation of state, the pressure is equal to that of a
noninteracting Fermi gas in the entire BCS-BEC crossover, which is not
consistent with the features of a weakly interacting Bose condensate in the BEC
limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of
the 2D mean-field theory indicates that the quantum fluctuations are much more
pronounced than those in 3D. In this work, we show that the inclusion of the
Gaussian quantum fluctuations naturally recovers the above features in both the
BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on
the boson chemical potential is recovered by the quantum fluctuations. Near the
quantum phase transition from the vacuum to the BEC phase, we compare our
equation of state with the known grand canonical equation of state of 2D Bose
gases and determine the ratio of the composite boson scattering length to the fermion scattering length . We find , in good agreement with the exact four-body calculation. We
compare our equation of state in the BCS-BEC crossover with recent results from
the quantum Monte Carlo simulations and the experimental measurements and find
good agreements.Comment: Published versio
Bayesian Hierarchical Model for Combining Two-resolution Metrology Data
This dissertation presents a Bayesian hierarchical model to combine two-resolution
metrology data for inspecting the geometric quality of manufactured parts. The high-
resolution data points are scarce, and thus scatter over the surface being measured,
while the low-resolution data are pervasive, but less accurate or less precise. Combining the two datasets could supposedly make a better prediction of the geometric
surface of a manufactured part than using a single dataset. One challenge in combining the metrology datasets is the misalignment which exists between the low- and
high-resolution data points.
This dissertation attempts to provide a Bayesian hierarchical model that can
handle such misaligned datasets, and includes the following components: (a) a Gaussian process for modeling metrology data at the low-resolution level; (b) a heuristic
matching and alignment method that produces a pool of candidate matches and
transformations between the two datasets; (c) a linkage model, conditioned on a
given match and its associated transformation, that connects a high-resolution data
point to a set of low-resolution data points in its neighborhood and makes a combined
prediction; and finally (d) Bayesian model averaging of the predictive models in (c)
over the pool of candidate matches found in (b). This Bayesian model averaging
procedure assigns weights to different matches according to how much they support
the observed data, and then produces the final combined prediction of the surface based on the data of both resolutions.
The proposed method improves upon the methods of using a single dataset as
well as a combined prediction without addressing the misalignment problem. This
dissertation demonstrates the improvements over alternative methods using both simulated data and the datasets from a milled sine-wave part, measured by two coordinate
measuring machines of different resolutions, respectively
Bi-Directional Generation for Unsupervised Domain Adaptation
Unsupervised domain adaptation facilitates the unlabeled target domain
relying on well-established source domain information. The conventional methods
forcefully reducing the domain discrepancy in the latent space will result in
the destruction of intrinsic data structure. To balance the mitigation of
domain gap and the preservation of the inherent structure, we propose a
Bi-Directional Generation domain adaptation model with consistent classifiers
interpolating two intermediate domains to bridge source and target domains.
Specifically, two cross-domain generators are employed to synthesize one domain
conditioned on the other. The performance of our proposed method can be further
enhanced by the consistent classifiers and the cross-domain alignment
constraints. We also design two classifiers which are jointly optimized to
maximize the consistency on target sample prediction. Extensive experiments
verify that our proposed model outperforms the state-of-the-art on standard
cross domain visual benchmarks.Comment: 9 pages, 4 figure
- …