9,593 research outputs found
Probability Thermodynamics and Probability Quantum Field
In this paper, we introduce probability thermodynamics and probability
quantum fields. By probability we mean that there is an unknown operator,
physical or nonphysical, whose eigenvalues obey a certain statistical
distribution. Eigenvalue spectra define spectral functions. Various
thermodynamic quantities in thermodynamics and effective actions in quantum
field theory are all spectral functions. In the scheme, eigenvalues obey a
probability distribution, so a probability distribution determines a family of
spectral functions in thermodynamics and in quantum field theory. This leads to
probability thermodynamics and probability quantum fields determined by a
probability distribution. There are two types of spectra: lower bounded
spectra, corresponding to the probability distribution with nonnegative random
variables, and the lower unbounded spectra, corresponding to probability
distributions with negative random variables. For lower unbounded spectra, we
use the generalized definition of spectral functions. In some cases, we
encounter divergences. We remove the divergence by a renormalization procedure.
Moreover, in virtue of spectral theory in physics, we generalize some concepts
in probability theory. For example, the moment generating function in
probability theory does not always exist. We redefine the moment generating
function as the generalized heat kernel, which makes the concept definable when
the definition in probability theory fails. As examples, we construct examples
corresponding to some probability distributions. Thermodynamic quantities,
vacuum amplitudes, one-loop effective actions, and vacuum energies for various
probability distributions are presented
Algorithm and experiments of six-dimensional force/torque dynamic measurements based on a Stewart platform
AbstractStewart platform (SP) is a promising choice for large component alignment, and interactive force measurements are a novel and significant approach for high-precision assemblies. The designed position and orientation (P&O) adjusting platform, based on an SP for force/torque-driven (F/T-driven) alignment, can dynamically measure interactive forces. This paper presents an analytical algorithm of measuring six-dimensional F/T based on the screw theory for accurate determination of external forces during alignment. Dynamic gravity deviations were taken into consideration and a compensation model was developed. The P&O number was optimized as well. Given the specific appearance of repeated six-dimensional F/T measurements, an approximate cone shape was used for spatial precision analysis. The magnitudes and directions of measured F/Ts can be evaluated by a set of standards, in terms of accuracy and repeatability. Experiments were also performed using a known applied load, and the proposed analytical algorithm was able to accurately predict the F/T. A comparison between precision analysis experiments with or without assembly fixtures was performed. Experimental results show that the measurement accuracy varies under different P&O sets and higher loads lead to poorer accuracy of dynamic gravity compensation. In addition, the preferable operation range has been discussed for high-precision assemblies with smaller deviations
Optimal Nonparametric Inference on Network Effects with Dependent Edges
Testing network effects in weighted directed networks is a foundational
problem in econometrics, sociology, and psychology. Yet, the prevalent edge
dependency poses a significant methodological challenge. Most existing methods
are model-based and come with stringent assumptions, limiting their
applicability. In response, we introduce a novel, fully nonparametric framework
that requires only minimal regularity assumptions. While inspired by recent
developments in -statistic literature (arXiv:1712.00771, arXiv:2004.06615),
our approach notably broadens their scopes. Specifically, we identified and
carefully addressed the challenge of indeterminate degeneracy in the test
statistics a problem that aforementioned tools do not handle. We
established Berry-Esseen type bound for the accuracy of type-I error rate
control. Using original analysis, we also proved the minimax optimality of our
test's power. Simulations underscore the superiority of our method in
computation speed, accuracy, and numerical robustness compared to competing
methods. We also applied our method to the U.S. faculty hiring network data and
discovered intriguing findings.Comment: 29 pages, 3 figure
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