arXiv subjects

P. Guo

Publications and source records attributed to P. Guo.

5 recordsLinked to original sources

arXiv2023

Application of Machine Learning Method to Model-Based Library Approach to Critical Dimension Measurement by CD-SEM

The model-based library (MBL) method has already been established for the accurate measurement of critical dimension (CD) of semiconductor linewidth from a critical dimension scanning electron microscope (CD-SEM) image. In this work the MBL method has been further investigated by combing the CD-SEM image simulation with a neural network algorithm. The secondary electron linescan profiles were calculated at first by a Monte Carlo simulation method, enabling to obtain the dependence of linescan profiles on the selected values of various geometrical parameters (e.g., top CD, sidewall angle and height) for Si and Au trapezoidal line structures. The machine learning methods have then been applied to predicate the linescan profiles from a randomly selected training set of the calculated profiles. The predicted results agree very well with the calculated profiles with the standard deviation of 0.1% and 6% for the relative error distributions of Si and Au line structures, respectively. This result shows that the machine learning methods can be practically applied to the MBL method for the purpose of reducing the library size, accelerating the construction of the MBL database and enriching the content of an available MBL database.

physics.comp-ph↗

arXiv2018

PILAE: A Non-gradient Descent Learning Scheme for Deep Feedforward Neural Networks

In this work, a non-gradient descent learning (NGDL) scheme was proposed for deep feedforward neural networks (DNN). It is known that an autoencoder can be used as the building blocks of the multi-layer perceptron (MLP) DNN, the MLP is taken as an example to illustrate the proposed scheme of pseudoinverse learning algorithm for autoencoder (PILAE) in this paper. The PILAE with low rank approximation is a NGDL algorithm, and the encoder weight matrix is set to be the low rank approximation of the pseudoinverse of the input matrix, while the decoder weight matrix is calculated by the pseudoinverse learning algorithm. It is worth to note that only very few network structure hyper-parameters need to be tuned compared with classical gradient descent learning algorithm. Hence, the proposed algorithm could be regarded as a quasi-automated training algorithm which could be utilized in automated machine learning field. The experimental results show that the proposed learning scheme for DNN could achieve better performance on considering the tradeoff between training efficiency and classification accuracy.

cs.LG↗

arXiv2016

Three-body final state interaction in $\eta \to 3 \pi$ updated

In view of the recent high-statistic KLOE data for the $\eta \to \pi^+ \pi^- \pi^0$ decay, a new determination of the quark mass double ratio has been done. Our approach relies on a dispersive model that takes into account rescattering effects between three pions via subenergy unitarity. The latter is essential to reproduce the Dalitz plot distribution. A simultaneous description of the KLOE and WASA-at-COSY data is achieved in terms of just two real parameters. From a global fit, we determine $Q=21.6 \pm 1.1$. The predicted slope parameter for the neutral channel $\alpha=-0.025\pm 0.004$ is in reasonable agreement with the PDG average value.

hep-ph↗

arXiv2014

Dispersive Analysis of $\omega/\phi \rightarrow 3\pi,\,\pi \gamma^*$

The decays $\omega/\phi \rightarrow 3\pi$ are considered in the dispersive framework that is based on the isobar decomposition and sub-energy unitarity. The inelastic contributions are parametrized by the power series in a suitably chosen conformal variable that properly accounts for the analytic properties of the amplitude. The Dalitz plot distributions and integrated decay widths are presented. Our results indicate that the final state interactions may be sizable. As a further application of the formalism we also compute the electromagnetic transition form factors of $\omega/\phi \rightarrow \pi^0\gamma^*$.

hep-ph↗

arXiv2013

Positronium in MOFs: the Atom out of the box

Recently, evidence for positronium (Ps) in a Bloch state in self-assembled metal--organic frameworks (MOFs) has been reported [Dutta et al., Phys. Rev. Lett. 110, 197403 (2013)]. In this paper, we study Ps emission into vacuum from four different MOFs crystals: MOF-5, IRMOF-8, FMA and IRMOF-20. Our measurements of Ps yield and emission energy into vacuum provide definitive evidence of Ps delocalization. We determine with a different technique Ps diffusion lengths in agreement with the recently published results. Furthermore, we measure that a fraction of the Ps is emitted into vacuum with a distinctly smaller energy than what one would expect for Ps localized in the MOFs' cells. We show that a calculation assuming Ps delocalized in a Kronig--Penney potential reproduces the measured Ps emission energy.

physics.atom-ph↗