Dop-DenseNet: Densely Convolutional Neural Network-Based Gesture Recognition Using a Micro-Doppler Radar

Le-Hai Cao,Hoang Van-Phuc,Doan Van Sang,Le Dai Phong 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.3

Hand gesture recognition is an efficient and practical solution for the non-contact human–machine interaction in smart devices. To date, vision-based methods are widely used in this research area, but they are susceptible to light conditions. To address this issue, radar-based gesture recognition using micro-Doppler signatures can be applied as an alternative. Accordingly, the use of a novel densely convolutional neural network model, Dop-DenseNet, is proposed in this paper for improving hand gesture recognition in terms of classification accuracy and latency. The model was designed with cross or skip connections in a dense architecture so that the former features, which can be lost in the forward-propagation process, can be reused. We evaluated our model with different numbers of filter channels and experimented with it using the Dop-Net dataset, with different time lengths of input data. As a result, it was found that the model with 64 3 × 3 filters and 200 time bins of micro-Doppler spectrogram data could achieve the best performance trade-off, with 99.87% classification accuracy and 3.1 ms latency. In comparison, our model remarkably outperformed the selected state-of-the-art neural networks (GoogLeNet, Res- Net-50, NasNet-Mobile, and MobileNet-V2) using the same Dop-Net dataset.

Laboratory Evaluation of Asphalt Mixtures Using Nano SIO2 to Improve Rutting Resistance

Van Bach Le,Van Phuc Le,Dong Nguyen 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

Rice husk, in large quantities, is released to the environment due to rice production in Vietnam. If this material can be utilized, it can solve not only the economic issues but also the environmental problems and sustainable development of the country. Laboratory evaluation of asphalt mixture using Nano silica made from rice husk to improve rutting resistance of asphalt mixtures was presented in this study. A 60/70 bitumen was used as control asphalt binder. The ratio of Nano SIO2 used in this study was 0.3%, 0,6%, 0,9%, 1,2%, and 1,5% by weight of powder. A dense gradation with nominal maximum aggregate size of 12.5mm was used for the asphalt mixtures. Marshall stability (MS) test and wheel tracking (WT) test were conducted to evaluate the rutting resistance of asphalt mixtures. It was found that the asphalt mixtures using 0.5%, 1.0%, and 1.5% Nano SIO2 have the rut depths of 5.35mm, 5.39mm, and 5.45mm, respectively, which is 30%, 31% and 29% lower than the control asphalt mixtures at 15,000 load cycles. Moreover, the static modulus of asphalt mixtures using 0.9% Nano SIO2 at 60oC is higher than the control mixtures. Based on the results of this study, it can be concluded that the addition of Nano SIO2 into asphalt mixtures can enhance the rutting performance of asphalt concrete under high temperatures significantly. It is noted that these conclusions were based on only on a limited number of samples and conditions. Further studies must be conducted to investigate the effect of Nano SIO2 on fatigue cracking and moisture damage of asphalt pavement in the field.

Performance Evaluation of 40/50 and 60/70 binder in Asphalt Mixtures

Van Hung Nguyen,Van Du Nguyen,Van Phuc Le 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

The main objective of this research study is the performance evaluation of 40/50 and 60/70 binder for asphalt mixtures in Vietnam. To accomplish the objective of this research, a dense gradation with nominal maximum aggregate size of 19.0mm is used for the asphalt mixtures. Marshall Stability (MS) test, Tensile Strength Ratio (TSR) test, Wheel Tracking (WT) test, and Dynamic modulus test are conducted to evaluate the rutting and cracking performance of 40/50 and 60/70 binder in asphalt mixtures. It was found that the Marshall stability of asphalt mixtures using 40/50 binder is about 12% higher than asphalt mixtures using 60/70 binder while the rutting resistance of the mixtures with 40/50 binder shows 2.5 times higher than 60/70 binder at 15,000 load cycles. Moreover, the TSR of asphalt concrete using 40/50 binder and 60/70 binder are approximately 95% and 79%, respectively which means that using 40/50 binder is very good for moisture damage resistance. Finally, the dynamic modulus test was done at a reference temperature of 20oC and frequency of 1,0Hz. The dynamic modulus of asphalt mixture with 40/50 binder is about 6257 MPa, which is two times higher than asphalt mixture using 60/70 binder. Based on the results of this study, it can be concluded that asphalt mixtures using 40/50 binder can improve the rutting and moisture damage resistance of asphalt concrete under high temperatures and moisture conditions significantly. It is noted that these conclusions were based on only on a limited number of samples and conditions. Further studies must be conducted to investigate the effect of 40/50 binder on fatigue cracking of asphalt pavement in the field.

New Approach to Construct Master Curve of Damaged Asphalt Concrete Based on Falling Weight Deflectometer Back-Calculated Moduli

Le, Van Phuc,Lee, Hyun Jong,Flores, Julius Marvin,Kim, Won Jae,Baek, Jongeun American Society of Civil Engineers 2016 Journal of transportation engineering Vol.142 No.11

<P>In this study, a frequency-temperature correction model and an approach to construct the master curve of damaged asphalt concrete based on falling weight deflectometer back-calculated moduli were presented. Falling weight deflectometer (FWD) testing and field coring was conducted in 26 locations in Seoul City in which back-calculated and laboratory measured modulus were compared. A frequency-temperature correction model is developed based on the frequency-temperature superposition principle and was verified by comparing to current temperature correction models. The proposed model has the lowest prediction error of 8.2% in comparing asphalt concrete dynamic modulus, but is limited within the linear range of the dynamic modulus and reduced frequency curve in a logarithmic scale. A new procedure in establishing damaged asphalt concrete (AC) master curves is proposed considering a damage factor which is used in determining damaged and parameters. It is verified using laboratory-measured modulus curves and is validated using FWD data obtained from literature. The validation study showed that the proposed procedures have an average error of 11.5%. Further study is recommended to enhance the proposed procedure to minimize error.</P>

Production of high purity rare earth mixture from iron-rich spent fluid catalytic cracking (FCC) catalyst using acid leaching and two-step solvent extraction process

Le-Phuc Nguyen,Yen Thi Hai Pham,Phuong Thuy Ngo,Tri Van Tran,Loc Vinh Tran,Nam Thi Hoai Le,Luong Huu Nguyen,Tung Thanh Dang,Duc Anh Nguyen,Marco Wenzel,David Hartmann,Karsten Gloe,Jan J. Weigand,Klaus 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5

Acid leaching and a two-step solvent extraction procedure were developed to produce high purity mixture of La and Ce from iron-rich spent FCC catalyst discharged from Dzung Quat refinery (Vietnam). Acid leaching of the spent catalyst with 2M HNO3 and a solid-to-liquid ratio of 1/3 at 80 oC in 1 h dissolved almost 90% of La while 12% of Al and 25% of Fe were transferred to the leachate. The extraction of RE metals and main impurities such as Al and Fe by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) was investigated. Experiments showed that it was necessary to remove Fe before extracting RE and the optimum extraction conditions for a high recovery of RE while 0% of Al extraction were pH1, contact time=10min, and D2EHPA/TBP volume ratio= 4 : 1. At these conditions, the extraction yields of La(III) and Ce(III) were 72% and 89%, respectively. A two-step solvent extraction was developed to achieve a high purity of RE mixture, which included (1) the removal of impurity Fe by 25% (v/v) diisooctyl phosphinic acid (DiOPA) in n-octane for 140 min, (2) the extraction of rare earths by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) in n-octane for 10 min without the need for adjusting the pH of the leaching solution.

Mental Health Among Healthcare Workers During the COVID-19 Pandemic in Vietnam

Nhan Phuc Thanh Nguyen,Ha Phan Ai Nguyen,Cao Khoa Dang,Minh Tri Phan,Huynh Ho Ngoc Quynh,Van Tuan Le,Chinh Van Dang,Tinh Huu Ho,Van Trong Phan,Van Trong Phan,Thang Phan,Dang Thi Anh Thu 대한예방의학회 2024 예방의학회지 Vol.57 No.1

Objectives: The objective of this study was to characterize mental health issues among Vietnamese healthcare workers (HCWs) and to identify related factors.Methods: A cross-sectional study was conducted with 990 HCWs in 2021. Their mental health status was measured using the Depression, Anxiety, and Stress Scale.Results: In total, 49.9%, 52.3%, and 29.8% of respondents were found to have depression, anxiety, and stress, respectively. The multivariable linear regression model revealed that factors associated with increased anxiety scores included depression scores (β, 0.45; 95% confidence interval [CI], 0.39 to 0.51) and stress scores (β, 0.46; 95% CI, 0.41 to 0.52). Factors associated with increased depression scores included being frontline HCWs (β, 0.57; 95% CI, 0.10 to 1.10), stress scores (β, 0.50; 95% CI, 0.45 to 0.56), and anxiety scores (β, 0.41; 95% CI, 0.36 to 0.47), while working experience was associated with reduced depression scores (β, -0.08; 95% CI, -0.16 to -0.01). Factors associated with increased stress scores included working experience (β, 0.08; 95% CI, 0.00 to 0.16), personal protective equipment interference with daily activities (β, 0.55; 95% CI, 0.07 to 1.00), depression scores (β, 0.54; 95% CI, 0.48 to 0.59), and anxiety scores (β, 0.45; 95% CI, 0.39 to 0.50), while age was associated with reduced stress scores (β, -0.12; 95% CI, -0.20 to -0.05).Conclusions: Specific interventions are necessary to enhance and promote the mental health of HCWs so they can successfully cope with the circumstances of the pandemic.

Brand Anthropomorphism, Brand Reputation, and Consumer Engagement in the Distribution of Smartphone Brands

Ngoc Dan Thanh NGUYEN(Ngoc Dan Thanh NGUYEN ),Trong Phuc NGO(Trong Phuc NGO ),Ngoc Van MAI(Ngoc Van MAI ),Kim Ngan TRA(Kim Ngan TRA ),Tran Huy Hoang LE(Tran Huy Hoang LE ) 한국유통과학회 2023 유통과학연구 Vol.21 No.4

Purpose: This study aims to analyze the impact of Brand Anthropomorphism and Intimacy on Brand Engagement, and at the same time analyze the regulatory effect of Brand Reputation on the relationship between Brand Anthropomorphism and Intimacy and the relationship between Intimacy and Brand Engagement in terms of distribution brand. Results: The findings show that Brand Anthropomorphism, Intimacy, and Brand Reputation are important value factors in customers’ minds toward their behavior, and from there, they will contribute to creating positive emotions and interactions between consumers and brands. Research design, data, and methodology: This article used the quantitative technique utilizing PLS-SEM software to test the hypothesis with 1,060 samples. Collected data shows that consumers in Ho Chi Minh City have positive emotions and interactive and social behaviors toward smartphone brands. Conclusion: The study has demonstrated the conclusions and proposed solutions to help smartphone brands build Brand Anthropomorphism while enhancing Brand Reputation thereby achieving Intimacy, which leads to consumer Brand Engagement. In addition, this study complements the concept of Brand Anthropomorphism which is lacking in theoretical background and is the first study in Vietnam to explore the prefixes and suffixes of the concept of Brand Anthropomorphism and the regulatory role of Brand Reputation.

ADSORPTION OF ZINC (Ⅱ) ONTO MnO₂/CHITOSAN COMPOSITE: EQUILIBRIUMAND KINETIC STUDIES

Van-Phuc Dinh,Ngoc-Chung Le,Ngoc-Tuan Nguyen 대한환경공학회 2015 대한환경공학회 학술발표논문집 Vol.2015 No.10

Delay Minimized and Energy-Efficient Data Collection with Dynamic Traffic in Wireless Sensor Networks

Phuc Nguyen Van,Le Duc Thang,Hyunseung Choo(추현승) 한국정보과학회 2013 한국정보과학회 학술발표논문집 Vol.2013 No.6

Switching and Electrical Memory Effect in the Colossal Permittivity Material La2NiO4+δ

Le Van Hong,Tran Dang Thanh,Dao Nguyen Hoai Nam,,Nguyen Xuan Phuc 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

La2NiO4+δ ceramic samples were manufactured by using a solid state reaction method. The crystalline structural, magnetic and dielectric properties of the material were recorded and analyzed. A dielectric resonance, which is thought to be associated with the multiferroic behavior of the material, was observed at frequencies below 1 MHz. The I/V characteristics were easured on a capacitor-like structure, which exhibited resistance and capacitance switching when opposite voltage pulses of about 2.5 volts with a duration time of 500 ms were applied. The maximum ratios of the changes in the resistance and the capacitance were estimated to be of about 50 % and 35 % at room temperature, respectively. The electrical switching was reversible, with resistive states remaining for a rather long time. The observed capacitance switching and memory effects provide evidence for the presence of charge transfer and accumulation in the material.