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59 - Jianjun Xu , Wenquan Cui 2020
This article studies global testing of the slope function in functional linear regression model in the framework of reproducing kernel Hilbert space. We propose a new testing statistic based on smoothness regularization estimators. The asymptotic dis tribution of the testing statistic is established under null hypothesis. It is shown that the null asymptotic distribution is determined jointly by the reproducing kernel and the covariance function. Our theoretical analysis shows that the proposed testing is consistent over a class of smooth local alternatives. Despite the generality of the method of regularization, we show the procedure is easily implementable. Numerical examples are provided to demonstrate the empirical advantages over the competing methods.
144 - Haoyu Zhang , Jianjun Xu , Ji Wang 2019
In this paper, we propose a novel pretraining-based encoder-decoder framework, which can generate the output sequence based on the input sequence in a two-stage manner. For the encoder of our model, we encode the input sequence into context represent ations using BERT. For the decoder, there are two stages in our model, in the first stage, we use a Transformer-based decoder to generate a draft output sequence. In the second stage, we mask each word of the draft sequence and feed it to BERT, then by combining the input sequence and the draft representation generated by BERT, we use a Transformer-based decoder to predict the refined word for each masked position. To the best of our knowledge, our approach is the first method which applies the BERT into text generation tasks. As the first step in this direction, we evaluate our proposed method on the text summarization task. Experimental results show that our model achieves new state-of-the-art on both CNN/Daily Mail and New York Times datasets.
Einstein-Podolsky-Rosens paper in 1935 is discussed in parallel with an EPR experiment on $K^0bar{K}^0$ system in 1998, yielding a strong hint of distinction in both wave-function and operators between particle and antiparticle at the level of quantu m mechanics (QM). Then it is proposed that the CPT invariance in particle physics leads naturally to a basic postulate that the (newly defined) space-time inversion (${bf x}to -{bf x},tto -t$) is equivalent to the transformation between particle and its antiparticle. The evolution of this postulate from nonrelativistic QM via relativistic QM till the quantum field theory is discussed in some detail. The Klein paradox for both Klein-Gordon equation and Dirac equation is also discussed. Keywords: CPT invariance, Antiparticle, Quantum mechanics, Quantum field theory
Based on the precision experimental data of energy-level differences in hydrogenlike atoms, especially the 1S-2S transition of hydrogen and deuterium, the necessity of establishing a reduced Dirac equation (RDE) with reduced mass as the substitution of original electron mass is stressed. The theoretical basis of RDE lies on two symmetries, the invariance under the space-time inversion and that under the pure space inversion. Based on RDE and within the framework of quantum electrodynamics in covariant form, the Lamb shift can be evaluated (at one-loop level) as the radiative correction on a bound electron staying in an off-mass-shell state--a new approach eliminating the infrared divergence. Hence the whole calculation, though with limited accuracy, is simplified, getting rid of all divergences and free of ambiguity.
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