Mitigating Data Scarcity for Neural Language Models

In recent years, pretrained neural language models (PNLMs) have taken the field of natural language processing by storm, achieving new benchmarks and state-of-theart performances. These models often rely heavily on annotated data, which may not always be available. Data scarcity are commonly found in specialized domains, such as medical, or in low-resource languages that are underexplored by AI research. In this dissertation, we focus on mitigating data scarcity using data augmentation and neural ensemble learning techniques for neural language models. In both research directions, we implement neural network algorithms and evaluate their impact on assisting neural language models in downstream NLP tasks. Specifically, for data augmentation, we explore two techniques: 1) creating positive training data by moving an answer span around its original context and 2) using text simplification techniques to introduce a variety of writing styles to the original training data. Our results indicate that these simple and effective solutions improve the performance of neural language models considerably in low-resource NLP domains and tasks. For neural ensemble learning, we use a multi-label neural classifier to select the best prediction outcome from a variety of individual pretrained neural language models trained for a low-resource medical text simplification task

Automatic limit and shakedown analysis of 3-D steel frames

This paper presents an efficient algorithm for both limit and shakedown analysis of 3-D steel frames by kinematical method using linear programming technique. Several features in the application of linear programming for rigid-plastic analysis of three-dimensional steel frames are discussed, as: change of the variables, automatic choice of the initial basic matrix for the simplex algorithm, direct calculation of the dual variables by primal-dual technique. Some numerical examples are presented to demonstrate the robustness, efficiency of the proposed technique and computer program

Retrieval of target structure information from laser-induced photoelectrons by few-cycle bicircular laser fields

Citation: Hoang, V. H., Le, V. H., Lin, C. D., & Le, A. T. (2017). Retrieval of target structure information from laser-induced photoelectrons by few-cycle bicircular laser fields. Physical Review A, 95(3), 6. doi:10.1103/PhysRevA.95.031402By analyzing theoretical results from a numerical solution of the time-dependent Schrodinger equation for atoms in few-cycle bicircular laser pulses, we show that high-energy photoelectron momentum spectra can be used to extract accurate elastic scattering differential cross sections of the target ion with free electrons. We find that the retrieval range for a scattering angle with bicircular pulses is wider than with linearly polarized pulses, although the retrieval method has to be modified to account for different returning directions of the electron in the continuum. This result can be used to extend the range of applicability of ultrafast imaging techniques such as laser-induced electron diffraction and for the accurate characterization of laser pulses

Factorization of high-harmonic generation yields in impurity-doped materials

We present a theoretical investigation of high-harmonic generation (HHG) from impurity-doped materials using the time-dependent Schr\"odinger equation (TDSE) approach. We demonstrate the factorization of HHG yields as a product of an electron wave packet and the recombination cross section, in analogy to HHG from atoms and molecules in the gas phase. Furthermore, we show that the quantitative rescattering model based on this factorization accurately reproduces the TDSE results. This opens up new possibilities to study impurities in materials using the available techniques from strong-field physics

FDI spill-overs, absorptive capacity and domestic firms' technical efficiency in Vietnamese wearing apparel industry

This study empirically examines relationship between FDI spill-overs and technical efficiency of domestic firms and role of the absorptive capacity of domestic firms. Data on Vietnamese Annual Enterprises Survey are exploited to build a firm-level panel data on the Vietnamese wearing apparel industry from 2009 to 2013. By applying stochastic production frontier model, this paper shows that there are positive vertical spill-over effects but no horizontal effects. Moreover, this study finds the negative impact of the absorptive capacity of domestic firms on benefits reaped from FDI externalities

An optimal Hardy-Littlewood-Sobolev inequality on Rn−k×Rn\mathbf R^{n-k} \times \mathbf R^n and its consequences

For $n > k \geq 0$, $\lambda >0$, and $p, r>1$, we establish the following optimal Hardy-Littlewood-Sobolev inequality $$\Big| \iint_{\mathbf R^n \times \mathbf R^{n-k}} \frac{f(x) g(y)}{ |x-y|^\lambda |y''|^\beta} dx dy \Big| \lesssim \| f \| _{L^p(\mathbf R^{n-k})} \| g\| _{L^r(\mathbf R^n)}$$ with $y = (y', y'') \in \mathbf R^{n-k} \times \mathbf R^k$ under the two conditions $$\beta < \left\{ \begin{aligned} & k - k/r & & \text{if } \; 0 < \lambda \leq n-k,\\ & n - \lambda - k/r & & \text{if } \; n-k < \lambda, \end{aligned} \right.$$ and $$\frac{n-k}n \frac 1p + \frac 1r + \frac { \beta + \lambda} n = 2 -\frac kn.$$ Remarkably, there is no upper bound for $\lambda$, which is quite different from the case with the weight $|y|^{-\beta}$, commonly known as Stein-Weiss inequalities. We also show that the above condition for $\beta$ is sharp. Apparently, the above inequality includes the classical Hardy-Littlewood-Sobolev inequality when $k=0$ and the HLS inequality on the upper half space $\mathbf R_+^n$ when $k=1$. In the unweighted case, namely $\beta=0$, our finding immediately leads to the sharp HLS inequality on $\mathbf R^{n-k} \times \mathbf R^n$ with the \textit{optimal} range $$0<\lambda<n-k/r,$$ which has not been observed before, even for the case $k=1$. Improvement to the Stein-Weiss inequality in the context of $\mathbf R^{n-k} \times \mathbf R^n$ is also considered. The existence of an optimal pair for this new inequality is also studied.Comment: 26 pages, 0 figur

Ectopic Pregnancy Located at Pelvic Wall and Liver: Two Uncommon Case Reports From Vietnam and Mini-Review Literature

INTRODUCTION AND IMPORTANCE: Abdominal ectopic pregnancy (AEP) located at hepatic region and pelvic-wall ectopic pregnancy (EP) are rare entities, that provoking a potentially life-threatening condition. Due to insufficient data, a proper management of non-specific types remains a challenge for all gynecologists worldwide. CASE PRESENTATION: Two child-bearing age women were hospitalized due to delayed menstruation and a urine pregnancy test was positive without a determination of intrauterine pregnancy. The first EP case was located at the pelvic wall which identified incidentally during laparoscopy for a presumed tubal ectopic pregnancy on ultrasonography throughout. The second EP case was found at the hepatic region due to intermittent pain rising from the right upper quadrant region and serial ultrasonic findings. In our management, both cases were successfully assessed by laparoscopy and laparotomy without requiring further intervention, respectively. CLINICAL DISCUSSION: An accurate diagnosis of EP location at liver and pelvic wall is totally difficult since its uncommon location. An initial assessment should be based on clinical symptoms and the treatment remains controversial. The surgical management including laparotomy and laparoscopy depends on clinical evaluation, experience of surgeon, and interdisciplinary team. Thus, these abnormal sites of ectopic pregnancy ought to take into consideration for all gynecologists in an emergency condition with a major hemorrhage. CONCLUSIONS: In reproductive age women, primary EP at liver and pelvic wall should be considered with high index of suspicion if intrauterine pregnancy is totally excluded. Timely diagnosis, rational management by surgical excision, and a multidisciplinary team can reduce substantially adverse outcomes