Search
Author
- Anh-Tuan Le (12)
- Quan-Hoang Vuong (12)
- Ngo Xuan Dinh (8)
- Minh-Hoang Nguyen (7)
- next >
Subject
- Nanoparticles (4)
- Open Science (4)
- Compound droplet (3)
- Economics (3)
- next >
Has File(s)
Search Results
Remote sensing of vital signals, including respiration and heartbeat signals, is an essential application of ultra-wideband impulse (UWB) radar. UWB radar measures the vital signal by a small motion of the thorax in the breathing and cardiac activities. The motion caused by cardiac activity is small compared to the motion of respiration and challenging to be detected in a real-life application. In this paper, we propose an algorithm for the enhancement of the signal-to-noise ratio (SNR) of the heartbeat signal. The proposed algorithm analyzes the correlation of the multichannel vital signals for taking the common harmonic component corresponding to the heartbeat signal. Thus, the algorithm could improve the SNR of the heartbeat signal over the referenced methods such as continuous w... |
This paper endeavors to understand the research landscape of finance research in Vietnam during the period 2008 to 2020 and predict the key defining future research directions. Using the comprehensive database of Vietnam’s international publications in social sciences and humanities, we extract a dataset of 314 papers on finance topics in Vietnam from 2008 to 2020. Then, we apply a systematic approach to analyze four important themes: Structural issues, Banking system, Firm issues, and Financial psychology and behavior. Overall, there have been three noticeable trends within finance research in Vietnam: (1) assessment of financial policies or financial regulation, (2) deciphering the correlates of firms’ financial performances, and (3) opportunities and challenges in adopting innova... |
This paper deals with the prediction of surface roughness in manufacturing polycarbonate (PC) by applying Bayesian optimization for machine learning models. The input variables of ultraprecision turning—namely, feed rate, depth of cut, spindle speed, and vibration of the X-, Y-, and Z-axis—are the main factors affecting surface quality. In this research, six machine learning- (ML-) based models—artificial neural network (ANN), Cat Boost Regression (CAT), Support Vector Machine (SVR), Gradient Boosting Regression (GBR), Decision Tree Regression (DTR), and Extreme Gradient Boosting Regression (XGB)—were applied to predict the surface roughness (Ra). The predictive performance of the baseline models was quantitatively assessed through error metrics: root means square error (RMSE), mean... |
This paper deals with second-order optimality conditions for a quasilinear elliptic control problem with a nonlinear coefficient in the principal part that is finitely PC2 (continuous and C2 apart from finitely many points). We prove that the control-to-state operator is continuously differentiable even though the nonlinear coefficient is non-smooth. This enables us to establish “no-gap” second-order necessary and sufficient optimality conditions in terms of an abstract curvature functional, i.e., for which the sufficient condition only differs from the necessary one in the fact that the inequality is strict. A condition that is equivalent to the second-order sufficient optimality condition and could be useful for error estimates in, e.g., finite element discretizations is also prov... |
We present the features of the fully flipped 3-3-1-1 model and show that this model leads to dark matter candidates naturally. We study two dark matter scenarios corresponding to the triplet fermion and singlet scalar candidates, and we determine the viable parameter regimes constrained from the observed relic density and direct detection experiments. |
Solutions for mitigating and reducing environmental pollution are important priorities for many developed and developing countries. This study was conducted to better understand the degree to which inner-city citizens and foreigners perceive air pollution and respond to it, particularly how much they willingly contribute to improving air quality in Vietnam, a lower-middle-income nation in Southeast Asia. During mid-December 2019, a stratified random sampling technique and a contingent valuation method (CVM) were employed to survey 199 inhabitants and 75 foreigners who reside and travel within the inner-city of Hanoi. The data comprises four major groups of information on: (1) perception of air pollution and its impacts, (2) preventive measures used to mitigate polluted air, (3) comm... |
Inspired by an interesting counterexample to the cosmic no-hair conjecture found in a supergravity-motivated model recently, we propose a multi-field extension, in which two scalar fields are allowed to non-minimally couple to two vector fields, respectively. This model is shown to admit an exact Bianchi type I power-law solution. Furthermore, stability analysis based on the dynamical system method is performed to show that this anisotropic solution is indeed stable and attractive if both scalar fields are canonical. Nevertheless, if one of the two scalar fields is phantom then the corresponding anisotropic power-law inflation turns unstable as expected. |
Fagopyrum esculentum (buckwheat) is an annual herb that is commonly cultivated in Vietnam for ornamental and food purposes. Previous studies also indicated the medicinal potential of the plant due to its high content of bioactive compounds. However, every year, more than 300 ha of buckwheat cultivation has been discarded after flower festival in North Vietnam. The present study was conducted to clarify the main chemical constituents of F. esculentum aerial parts collected in Ha Giang, Vietnam. The investigation has led to the isolation and identification of nine compounds, specifically flavonoids (rutin, quercetin, quercetin 3-O-rhamnopyranoside, quercetin 3-O-galactopyranoside), lignan (isolariciresinol), phenylpropanoids linking with sucrose (lapathoside A, lapathoside D) and phyt... |
Logically, and by most common standards, academics would be pleased to be cited, considering it a form of recognition of their intellect. In return, especially those with high citation counts, such as Clarivate Analytics’ Highly Cited Researchers, can benefit through peer recognition, rewards, funding, securing a better position, or expanding a collaborative network. Despite known and untold benefits, one issue has not been discussed: the right to refuse to be cited or the right to refuse a citation. Academics might not want to be cited by papers published in truly predatory journals, papers with false authors, or sting papers with falsified elements that employ underhanded ethical tactics. Currently, academics generally have the freedom to select where they publish their findings a... |
This work reports on the synthesis, characterization, and photocatalytic performance of the TiO2 inverse opal nanostructure (IP-TiO2) and the IP-TiO2 modified by Ag nanoparticles (Ag@IP-TiO2). The IP-TiO2 is fabricated using polystyrene spheres as the template and TiCl4 as the precursor, and the Ag@IP-TiO2 is realized by photoreduction method. The morphological, structural, and optical properties of the materials are investigated by scanning electron microscopy, X-ray diffraction, ultraviolet–visible (UV-VIS) absorption spectroscopy, and photoluminescence spectroscopy. Their photocatalytic performances are studied by the degradation of rifampicin antibiotic under the visible-light irradiation generated by an LED lamp. The results demonstrate that the IP-TiO2 is composed of mesopores... |
