VNUHCM Journal of Science and Technology Development

AiMA - An AI-Based Mobile System to Assist College Students with Math-Related Issues

Tan Duy Le — 2023-09-30

Introduction: As technology continues to progress, the importance and influence of mathematics in people's lives are growing. The emergence of mobile systems has brought about several benefits, such as portability, convenience, and accessibility, especially in the field of education. It is crucial to develop a mobile system that can cater not only to high school students but also to those enrolled in colleges and universities, offering solutions for basic calculations and highly specialized algorithms. To address this need, this research presents AiMA, an AI-based mobile system that assists college students with math-related issues.

Methods: In this paper, we discuss the limitations of current math-solving mobile applications and propose a solution that caters to specialized algorithms for university students. AiMA employs React Native on the front-end side to render the user interface and Flask-server on the back-end side to handle numerical data. Additionally, an AI model is implemented to handle input images stored in a cloud-based media management platform for detection.

Results: The system's functionality evaluation indicates that AiMA provides advantages over existing solutions by enabling users to solve complex calculus problems and receive tailored solutions for specific areas of mathematics.

Conclusion: This makes AiMA a highly valuable tool for college and university students who require specialized assistance with their math-related studies.

Removing tannins and debittering brewer’s spent yeasts by Tween 80

Thi Minh Xuan Nguyen — 2023-09-30

Introduction: Yeast extract from brewer's spent yeast cells is a promising nutrition source for many applications in the food industry and biomass production. However, because of the impurities that cause the bitter and astringent flavor attributed to hop resins during fermentation, brewer's spent yeasts in the industry have not been widely used. Contaminants have been withdrawn by using a variety of techniques. However, most reported methods have focused on removing iso-alpha acid rather than tannin, which has anti-digestive and antimicrobial properties. This study focuses on removing tannins and evaluating their impact on reusing brewer's spent yeast in biomass production.

Methods: In this work, Tween 80 was employed for the removal of tannins and other bitter substances from brewer’s spent yeasts. In addition to biochemical approaches, the efficiency of cultivating probiotics with autolysates from yeasts cleaned by various buffers is used to evaluate the effectiveness of eliminating tannins and bitter compounds.

Results: In tannin removal, the outstanding efficiency of Tween 80 was four times higher than that of water and hypotonic 0.5% NaCl solution. The debittering efficiency increases from 77% to 83.6% by using Tween 80. Therefore, the cell density of Lactobacillus fermentum 4C cultures with the autolysate from Tween 80-treated spent yeast cells increased by 16.5% and 10.2% compared to that of cultures washed with distilled water or 0.5% NaCl, respectively. The autolysate of Tween 80-treated yeast cells is rich in protein and α-amino nitrogen. It shows advantages in culturing different strains of probiotics.

Conclusions: By skipping the first stage of biomass creation, the reuse of spent yeasts in the production of yeast extracts will not only address environmental issues but also have a positive economic impact.

Synthesis of donor and acceptor monomers for conjugated polymers in organic optoelectronic applications

Minh Duy Hoang — 2023-09-30

Introduction: In today's life, conductive polymers play an increasingly important role, and it is very important to research and find materials with new properties and the ability to improve the performance of devices. The synthesis of monomer units as donor-acceptor structural units in conducting polymers is extremely important.

Methods: In this research, the process of synthesizing these potential monomer structural units with high efficiency has been described, including three main units, (4-hexyl-phenyl)(10H-phenoxazin-10-yl)methanone (HP-POzM) (58%, yield), 4,8-bis(hexyloxy)benzo[1,2-b:4,5-b']dithiophene (BHBDT) (90%, yield) and 5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (EHTPD) (95%, yield).

Results: The successful synthesis of monomers was demonstrated by qualitative analytical measurements of 1H NMR and TLC monitor. In addition, it is an overview of the direction that scientists are aiming for these monomer units, as D-A units in conductive polymers, applied in current fields and development orientation in the future.

Robot Gesture Control using Online Feedback Data with Multi-Tracking Capture System

Phu Xuan Do — 2023-09-30

This study employs a Vicon, high-speed and accurate marker-based motion capture system to develop a wireless low-latency gesture control method that requires no additional hardware components or onboard power sources. A novel control method is designed to track a rigid-body object's motion in the workspace and translate it into robot control signals. The system comprises five main components: a host PC with Vicon software named Tracker, a set of eight Vicon Vantage V8 infrared cameras, a client PC that receives Tracker's broadcasted data over Ethernet, a robot model named youBot provided by KUKA, and a rigid-body object that acts as the gesture controller. By using an Application Programming Interface (API) called DataStream, the rigid-body object's pose (position and orientation) can be estimated and used to remotely control the KUKA youBot robot with higher accuracy and an overall reduced latency of 0.3 seconds. In comparison to existing methods based on accelerometer-based and gyroscope-based controllers, the proposed gesture controller uses a set of retro-reflective markers for tracking purposes and requires no additional hardware systems. This proposed control method proves especially beneficial for the robotics prototyping development phase, where different control mechanisms can be easily replicated and tested within the motion capture system's operating range. Additionally, the robot's odometry can also be tracked during testing, making a motion capture system a valuable tool for evaluating motion control methods.

Effects of pasteurization on the physicochemical, sensory properties and microbiological quality of beetroot (Beta vulgaris L.) wine during storage

Giang Thi Huong Nguyen — 2023-09-30

Introduction: In the beverage sector, pasteurization is combined with another means of preservation such as concentration, acidification to extend product shelf-life by inactivating all non-spore-forming pathogenic bacteria and the majority of vegetative spoilage microorganisms, as well as inhibiting or stopping microbial and enzyme activity. The main objective of this study was to focus on the effect of pasteurization and storage on the physical, antioxidant, and microbiological properties of red beetroot (beta vulgaris l.) wine. Method: After fermentation in 10 days, the red beetroot wine was either pasteurized at 70⁰C in 10 minutes or unpasteurized before storing at 4⁰C in different time (1 month, 2 months). Physicochemical properties and microbiological quality of beetroot wine were analyzed to study effect of pasteurization and storage on those properties of beetroot wine. Results: Physical properties like pH, total dissolved solids content were significantly affected by pasteurization (higher pH and higher TTS in pasteurized samples than in unpasteurized samples) but they were not affected by storage time in this project. After fermentation, the TPC of red beetroot wine was lost but it kept unchanged after pasteurization. Vitamin C of the wine sample was lost after pasteurization only when storage. Pasteurization and 2 month-storage caused significant reduction on antioxidant capacity of red beetroot wine. Sensory quality of beetroot wine was not affected by pasteurization but it was in the case of storage. Microorganism quality of wine was acceptable for consumption. Pasteurization process is effective in increasing shelf life of red beetroot wine but does not significantly affect its nutritional and sensory values.

Keywords: Red beetroot spirit, pasteurization, storage, total phenolic content, antioxidant capacity, vitamin C.

A survey of AI-based robotic process automation for businesses and organizations

Thon-Da Nguyen — 2023-09-30

This paper explores the theories and practical applications of AI, AI-based RPA and RPAn in enterprises as well as in organizations. Recent advanced and modern techniques of AI, AI-based RPA and RPA are also presented and discussed in this study. In addition, this study also presents individual and combined solutions in applying AI-based RPA for small-cap companies to leading and multinational companies. Research results show that AI-based RPA technology has very good applications to replace human activities in many different fields and industries, such as economics, administration, business, banking, marketing, and medical care.

Synthesis of a self-healing polymer blend containing dynamic diels-alder and h-bond crosslinks

Mai Ly Nguyen Thi — 2023-09-30

Introduction: It is unquestioned that self-healing polymers are being applied in numerous applications due to their indiscernible advantages, such as the extension of materials’ life span. Not surprisingly, researchers throughout the world concentrate on boosting the progression of the polymer. However, it takes 24 h or 48 h for the self-healing process of polymer-based materials in manifold studies to be efficacious. This can be thought of as a problematic hurdle slowing its advancement and application. Therefore, our research was conducted in an attempt to create a blended structure through hydrogen interplay between (thio)urethane bonds and H-acceptor heterocyclic moieties.

Method: The integration of 5 wt%, 10 wt% and 20 wt% blended copolymer capable of forming H-bonds into the network structure was performed to gain a network blend. Furthermore, ATR-FTIR spectroscopy, shape-memory and self-healing tests were employed for the determination of hydrogen bond formation coupled with various properties.

Result: From the ATR-FTIR results, the occurrence of H-bonds was proven. In addition, the blends’ rates of shape recovery and shape fixity rates were more than 99%. It contributes to the mechanical recovery at 82.75% with the addition of 10 wt% of the blended copolymer after 10 h at 70 °C, surpassing those of the 5 wt% and 20 wt% blends.

Conclusion: This study will pave the way for self-heling polymers to be utilized in different fields in the future.

Improving the performance of the GPS/INS integrated navigation system by using the real-time kinematic method

Dung Quoc-Tien Tran — 2023-09-30

Introduction: This paper presents a method for improving the accuracy of a GPS/INS integrated navigation system. Estimating the yaw angle, which is the degree of deviation from the north, is a crucial aspect in the navigation and control of autonomous robots.

Methods: We can use an inertial measurement unit (IMU) to calculate the yaw angle, but the accuracy is heavily reliant on the Earth's magnetic field. This field can vary in value as the vehicle moves and is easily disturbed by external sources such as electrical devices and motors. To circumvent these limitations, a dual-antenna GPS with the real-time kinematic (RTK) method is utilized to improve the quality of the yaw angle estimation.

Results: This approach eliminates the use of magnetometers, and the experimental results show that the error can be significantly reduced to 0.16 degrees with a baseline of 1 meter.

Conclusion: When compared to the standard GPS/INS system, the proposed method using GPS-RTK provides better accuracy, even when the GPS signal is lost.

Self-couplings of gauge bosons in 3-4-1 models

L. T. Hue — 2023-09-30

Feynman rules for self-couplings of the gauge bosons in the general 3-4-1 model based on the gauge group $SU(3)_c\otimes SU(4)_L \otimes U(1)_X$ will be presented in this work. The results are checked to be consistent with previous works. The results also confirm important relations between different triple and quartic gauge couplings assumed previously for constructing general one-loop contributions to physical processes searched by experiments.

Determination of ethanol in hand sanitizers by a self-built headspace device and gas chromatography

Gia-Huy H. D. — 2023-09-30

Introduction: Headspace sampling coupled with gas chromatography (HS-GC) has been proven to be a very useful technique for the determination of volatile and semivolatile components in complex matrices by avoiding tedious sample preparation. In this study, the HS system was fabricated at low cost, exploiting unused GC sensor-heaters.

Methods: The accuracy and stability of the self-built HS were evaluated, and the HS-GC-FID system was applied to the determination of ethanol in hand sanitizer gels. The HS operating conditions, including temperature and equilibrium time, were optimized using a central composite face-centered design (CCFC) and MODDE 5.0 software. Samples incubated at 80 °C for 25 min gave the best results with respect to sensitivity and reproducibility (RSD < 3%).

Results: The calibration curve showed high linearity (R2 > 0.998) in the range of 0.25 to 2.5% (w/w) ethanol, using acetonitrile 1% (w/w) as an internal standard. The recovery ranged between 104.1 and 108.3% using spiked samples on real matrices. A small survey of 11 commercially available samples collected in the local markets showed that only one of them did not meet the standards set by the FDA.

Sensitivity of secondary particle emission to hadronic physics models in GATE/Geant4 proton therapy simulations at 100 MeV

Pham Thi Cam Lai — 2023-09-30

Introduction: Proton therapy simulations rely on Monte Carlo techniques, such as the GATE code based on the Geant4 toolkit, to predict dose distribution and secondary particle production. The accuracy of these simulations is heavily influenced by the chosen physics models.

Methods: In this study, we analyzed three Geant4 hadronic physics models, BIC, BERT, and INCL++, by calculating the angular and energy distributions of secondary neutrons and gamma particles. We conducted GATE/Geant4 simulations on a water phantom irradiated with a 100 MeV proton beam.

Results: Our investigation revealed notable differences in the angular and energy distributions of emitted particles among the three models.

Conclusion: This study emphasizes the necessity of carefully selecting a hadronic physics model for GATE/Geant4 simulations in proton therapy.

Study on the flowering in rice plant (Oryza sativa cv. OM5451)

Tran Minh Hong Linh — 2023-09-30

Introduction: The consumption of rice is rising in response to worldwide population development. The purpose of this study was to determine the stages of plant development, specifically the transition stage from panicle initiation to the flowering stage, which determines the number of spikelets per branch. In addition, this research studied the changes in physiology and morphology during the flowering development of rice in a garden.

Methods: Plant height, number of leaves, number of tillers, and flowering time were all measured. Plant growth regulators such as cytokinin, auxin, gibberellic acid (GA), and acid abscisic (ABA) in the apical shoot at different stages of flower development were analyzed.

Results: The activities of indole acetic acid (IAA), zeatin, and gibberellins in the apical shoot of the stem elongation stage are higher than those in plants of the panicle initiation stage. At the flowering stage, the rates of photosynthesis and respiration of the leaves at positions 1, 2, and 3 were higher than those of the other leaves. In addition, photosynthetic pigments at leaf positions 2, 3, and 4 were higher than those at positions 1 and 3.

Conclusion: The results show that the relationship between changes in morphological, physiological, and biochemical indicators during the rice growth stages was discussed.

Stable strong duality for cone-constrained set-valued optimization problems: A perturbation approach

Dinh Nguyen — 2023-09-30

In this paper we consider a general set-valued otimimization problem of the model

Winf F(x), s.t. x in X

where $F\colon X\rightrightarrows Y\cup\{+\infty_{Y}\}$ is a proper mapping. The problem is then embed into a parametric problem and can be express as

(P) $\mathop{\winf}\bigcup\limits_{x\in X}\Phi(x,0_Z)$

where $\Phi\colon X\times Z\rightrightarrows Y^\bullet$ is a proper set-valued {\it perturbation mapping} such that $ \Phi(x,0_Z) = F(x) $. A representation of the epigraph of the conjugate mapping $\Phi^\ast$ is established (Theorem 1) and it is used as the basic tool for establishing a general stable strong duality for the problem (P) (Theorem 3). As applications, the mentioned general strong duality result is then applied to a cone-constrained set-valued optimization problem (CSP) to derive three dual problems for (CSP): The Lagrange dual problem and two forms of Fenchel-Lagrange dual problems for (CSP). Consequently, three stable strong duality results for the three primal-dual pairs of problems are derived (Theorems 4 and 5), among them, one is entirely new while the others extend some known ones in the literature.

Behavioral activities of the giant water bug Lethocerus indicus (Lepeletier et Serville, 1775)

Sakkouna Phommavongsa — 2023-09-30

The study on behavioral activities of the giant water bug Lethocerus indicus was conducted at the Centre for Biodiversity Resources Education and Development (CEBRED), Hanoi National University of Education (HNUE). Twelve types of behavioral activity (BA) were identified and described: BA1: Horizontally floating, BA2: Diagonally floating, BA3: Swimming on the water surface, BA4: Swimming under the water surface, BA5: Respiration by extension and retraction pair of siphon, BA6: Capturing and eating prey, BA7: Vibrating legs, BA8: Openning and flapping wings, BA9: Clinging to each other, BA10: Crawling out of water, BA11: Death-feigning, and BA12: Attacking and cannibalizing each other. These 12 behavioral activities observed descended in the following order: (1) BA2 (17,24%) >(2) BA4 (16,94%) >(3) BA3 (15,75%) >(4) BA5 (14,86%) >(5) BA1 (12,18%) >(6) BA6 (11,14%) >(7) BA9 (6,99%) >(8) BA7 (2,97%) >(9) BA8 (1,34%) >(10) BA12 (0,30%) >(11) BA10 (0,15%) >(12) BA11 (0,15%). These behavioral activities can be grouped into 3 groups based on their scientific basis: Genetically (92%) >Ecologically (4.5%) >Physiologically (3.5%). This research on the behavioral activities of the giant water bug Lethocerus indicus can be considered an important scientific basis to be implemented in the raising and sustainable conservation of the species listed in The Vietnam Red Data Book since 1992.

Toward Plasmon-Controlled Generation of the Activating Ag Hotspot Nanospheres for Quantitative SERS Analysis

Nguyen Tran Gia Bao — 2023-10-10

Introduction: Surface-enhanced Raman scattering (SERS) has attracted enormous concern as a robust vibrational spectroscopy technique with widespread applications, primarily for the ultrasensitive detection of low-concentration molecules and selective identification. Nevertheless, the optimization of SERS efficiency has been impeded by limitations in controlling the size of nanoparticles utilized in this technique. Method: In this study, the morphology, structure, chemical components, and optical properties of the as-synthesized Ag nanoparticles (Ag NPs) via a hydrothermal method were thoroughly investigated by sophisticated analyses. The synthesized Ag NPs were characterized for its morphological characteristics using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis absorption spectroscopy, Raman spectroscopy, and assessed for their SERS performance in detecting organic substances including Crystal Violet (CV) and Rhodamine B (RhB). Results: The results showed that Ag NPs with different sizes could be obtained from 10 to 30 nm. These sizes corresponded to the duration of the hydrothermal method, which was 15, 20, and 25 hours, respectively. The optimal sample exhibited the capability to detect dye molecule solutions at diluted-low concentrations as low as 10^-8 M. Conclusion: Through these results, we contribute to advancing the understanding of tailored nanoparticle synthesis for superior SERS performance, thus opening avenues for enhanced molecular detection in various applied analytical fields.

A study on the optical properties of a novel flower-core photonic crystal fiber infiltrated with CCl4

Thuy Nguyen Thi — 2023-10-10

A novel design of photonic crystal fiber with a flower-core is proposed for the first time to optimize dispersion suitable for broadband supercontinuum generation. The numerical simulation of the propagation of light modes in optical fibers is computed by solving Maxwell's wave equations with the full-vector finite-difference eigenmode method. As a result, near-zero ultra-flat all-normal and anomalous dispersion was achieved with fluctuations of ±0.978 ps/nm.km in the 294 nm wavelength region and ±1.168 ps/nm.km in the 432 nm wavelength region, respectively. Furthermore, the dispersion value at the pump wavelength is about 10 times lower than in previous papers. The combination of CCl₄ infiltration into the hollow core and the air hole's size heterogeneity in the cladding also enhances the nonlinear properties of the fibers. The effective mode areas less than 2 µm² at the pump wavelength can help the supercontinuum spectrum to broaden further towards the red wavelength region. Three fibers with structural parameters Ʌ = 0.8 µm, d₁/Ʌ = 0.45, Ʌ = 0.9 µm, d₁/Ʌ = 0.5, and Ʌ = 0.9 µm, d₁/Ʌ = 0.45 are proposed for supercontinuum generation with low peak power due to the nonlinear coefficients as high as hundreds W⁻¹.km⁻¹. These fibers are a new class of optical fibers, highly efficient laser sources that replace traditional glass-core optical fibers.

Analysis of the Influence of Financial Informatization on Improving Financial Control Ability

Jun Gao — 2023-09-30

This paper mainly conducts in-depth research on the influence of financial informatization on improving financial control ability. According to the advantages of combining financial management and informatization, it expounds the role of financial informatization in improving financial control ability, such as constantly improving the quality of financial internal control, helping to improve the quality of financial management, achieving the integration of financial and business management development objectives, improving the work quality of financial personnel, strengthening the ability to control enterprise risk, and providing a high-quality platform for enterprise financial management and assessment. Then, it puts forward some feasible measures for the construction of informatization, mainly including employees continuously improving financial management consciousness, innovating financial management methods and systems, promoting the full use of financial information and strengthening the informatization construction of enterprise financial management work safeguard mechanisms to realize financial informatization construction and improve financial control ability.