Các bài báo

• DEVELOPMENT OF A SEMI-ANALYTICAL MODEL FOR SUBSURFACE STRESS IN ELASTIC CONTACT

  La Hoang De, Hoang Anh Le, Tat Tai Truong (Tác giả)

  Tóm tắt | PDF | Lượt xem: 32 | Tải xuống: 0

  The paper presents the development of a semi-analytical model to describe subsurface stress distribution in linear elastic contact problems. The model is constructed based on the Hertzian pressure distribution on the contact surface combined with a depth attenuation function derived from the Padé approximation of the Green’s function solution in an elastic half-space. By analyzing fundamental physical conditions of the problem, including boundedness at the surface, force equilibrium, and the asymptotic behavior of the Boussinesq solution, the study demonstrates that a cubic-order attenuation function provides a reasonable representation of the stress field with depth. The proposed model is capable of reproducing the three-dimensional stress distribution with small deviations compared to the classical Hertz–Boussinesq solution, while maintaining a compact analytical form suitable for efficient computation. The results indicate that the model has potential applications in contact mechanics, subsurface stress analysis, and preliminary evaluation of contact fatigue phenomena in elastic materials.

• PRELIMINARY STUDY ON THE IMPACT OF TEMPERATURE AND HUMIDITY INDEXES ON ANTLER PRODUCTION AND POST-HARVEST RECOVERY IN DEER IN DONG THAP PROVINCE

  Phong Tran Dac, Tuong Nguyen Huy, Si Nguyen Tien, Tham Ho Thanh (Tác giả)

  Tóm tắt | PDF | Lượt xem: 62 | Tải xuống: 0

  This study was conducted to evaluate the effects of the Temperature–Humidity Index (THI) on velvet antler yield and clinical recovery following antler harvesting in sika deer in Dong Thap Province, Vietnam. The experiment was carried out on six male sika deer aged 3–4 years, using an anesthesia protocol consisting of Xylazine hydrochloride and reversal with Yohimbine hydrochloride. The THI was recorded at three time points (before antler cutting, 15 minutes and 1 hours post-cutting). Four recovery milestones were also monitored, including induction of anesthesia, antler cutting, regaining consciousness, and complete recovery.

  Regression analysis showed that the THI measured before antler cutting had a statistically significant effect on the antler yield ratio (P = 0.033), with an adjusted coefficient of determination R²(adj) of 70.6%. During the antler harvesting procedure, the mean recovery time was very short, averaging 1.36 ± 1.13 minutes, and the deer were able to walk normally after 11.74 ± 4.41 minutes. Although environmental conditions fluctuated and the maximum THI reached 84.29, all experimental deer recovered rapidly, with no cases of respiratory depression or seizures observed, and all antler wounds remained dry within 24 hours after cutting. These preliminary findings suggest that monitoring and controlling THI, together with an appropriate anesthesia and recovery protocol, may contribute to improved velvet antler production and enhanced animal welfare in sika deer under practical farming conditions in Southern Vietnam.

• AN EXPLAINABLE DEEP LEARNING MODEL FOR ALZHEIMER’S DIAGNOSIS

  Khac Tuong Nguyen, Anh Cang Phan (Tác giả)

  Tóm tắt | PDF | Lượt xem: 59 | Tải xuống: 0

  Alzheimer’s disease is a neurodegenerative disorder causing cognitive decline and memory loss. This study proposes XAI-NET, a deep learning model leveraging architectures such as EfficientNet_V2, MobileNet_V2, and Xception for MRI-based diagnosis. Explainable AI techniques, including SHAP and LIME, are applied to enhance model transparency and interpretability. Experimental results on the ADNI dataset demonstrate high accuracy and robustness, supporting early and reliable Alzheimer’s diagnosis.

• PREVALENCE AND TREATMENT EFFICACY OF ABOMASAL WORM INFECTION IN CASTLE IN TAN HO CO AND TAN THANH COMMUNES DONG THAP PROVINCE

  Tri Nguyen Duc, Tam Quach Thi Thanh (Tác giả)

  Tóm tắt | PDF | Lượt xem: 38 | Tải xuống: 0

  This study was conducted to determine the prevalence of bovine abomasal nematodes infection in cattle in Tan Ho Co and Tan Thanh communes, Dong Thap Province, and to evaluate the efficacy of fenbendazole and Portulaca oleracea in the treatment of bovine abomasal worm infection. The treatment experiment consisted of four treatment groups, with 18 cattle each group: NT1 (fenbendazole), NT2 (SAM250), NT3 (SAM300), and NT4 (SAM350) received P. oleracea at doses of 250g, 300g, and 350g/100 kg cattle, respectively. The results showed that the prevalence of bovine abomasal nematodes infection in cattle in Tan Ho Co commune (46.71%) was significantly higher than that in Tan Thanh commune (28.48%) (p< 0.05). In terms of therapeutic efficacy, cattle in NT4 (SAM350) and NT3 (SAM300) achieved anthelmintic efficacy with 100% against abomasal nematodes, equivalent to NT1 (fenbendazole) and significantly higher than NT2 (SAM250) at 72,22% (p<0,05). Furthermore, body weight gain was significantly improved in NT4 (8.52 kg/head) and NT3 (8.45 kg/head) compared to NT1 (6.95 kg/head) and NT2 (5.20 kg/head) ( ). No adverse clinical reactions were observed in cattle receiving Portulaca oleracea in NT4 (SAM350), NT3 (SAM300) và NT2 (SAM250) during the experimental period. These findings demonstrate that administering 300g or 350g of Portulaca oleracea per 100 kg of body weight exhibits significant potential for controlling abomasal nematode infections and enhancing growth performance in cattle under the current study conditions, thereby providing a promising approach to minimize the reliance on pharmaceutical anthelmintics in parasite management.

• ANALYZING FUSION MECHANISMS IN MULTI-BEHAVIOR RECOMMENDATION SYSTEMS

  Hien Le Thi Hanh, Tuong Nguyen Lan, Khoa Ho Chan, Thanh Ta Minh, Nghe Nguyen Thai (Tác giả)

  Tóm tắt | PDF | Lượt xem: 45 | Tải xuống: 0

  Analysis of fusion mechanisms in multi-behavior recommendation on the Taobao dataset for predicting purchase behavior under sparse and imbalanced conditions. Four fusion strategies are examined: early fusion (BPR-MF with Weighted Sum), late fusion (NeuMF), intermediate fusion (MBGCN), and model-level fusion (PLE). Experimental results show that PLE achieved the highest Recall and Precision, while MBGCN achieved the highest NDCG, reflecting its ability to improve ranking quality at the top positions. Overall, simultaneously leveraging multiple auxiliary user behaviors such as viewing, liking, and adding to cart enhances the effectiveness of predicting purchase behavior in a sparse and unbalanced data environment.

• ANALYSIS OF BRAKING DYNAMICS AND THERMAL CHARACTERISTICS IN PASSENGER CARS BASED ON A BIDIRECTIONAL INTERACTION MODEL

  Võ Huỳnh Phi, Vân Nguyễn Thái, Vũ Dương (Tác giả)

  Tóm tắt | PDF | Lượt xem: 147 | Tải xuống: 102

  This paper investigates the bidirectional interaction between brake actuation parameters and vehicle dynamics, alongside thermal analysis of disc brake assemblies based on a simplified equivalent thermal model. A generalized Matlab-based algorithm is developed to simulate the variation of braking dynamic state parameters under optimal braking (forward approach) and evaluate Mean Fully Developed Deceleration (MFDD) in accordance with UN R13-H regulations (inverse approach). Simulation results across various load cases demonstrate consistent alignment between brake actuation parameters and braking dynamics, while confirming that MFDD values satisfy international standards. Furthermore, a simplified thermal model in Ansys Workbench verifies that the temperatures generated at the friction interfaces remain within the stable friction zone of the brake components.

• INVESTIGATION OF FACTORS AFFECTING EXTRACTION YIELD AND ANTIBACTERIAL ACTIVITY OF PIPER BETLE LEAF ESSENTIAL OIL WITH ESCHERICHIA COLI

  Thai Do Quoc, Tuong Nguyen Huy, Hao Pham Chi (Tác giả)

  Tóm tắt | PDF | Lượt xem: 35 | Tải xuống: 0

  The present study was conducted to evaluate the factors affecting the essential oil content obtained by steam distillation and to assess the antibacterial activity of betel leaf (Piper betle L.) essential oil against E. coli bacteria. The results showed that (i) the highest essential oil yield was 0.43% with the sample of pureed leaves soaked in warm water for 30 minutes, extracted for 120 minutes, with a 15% NaCl concentration, a 700 ml volume of water added to the flask, and at a temperature of 100°C; (ii) the main antibacterial components of betel leaf essential oil included phenolic and terpene compounds characteristic of betel leaf essential oil, most notably eugenol acetate (17.95%); (iii) betel leaf essential oil exhibited strong antibacterial activity against E. coli bacteria, where the 100% essential oil concentration resulted in the largest diameter of the inhibition zone.

• SEMANTIC RETRIEVAL FOR RECOMMENDATION SYSTEMS WITH  LARGE LANGUAGE MODEL

  Mai Tran Thu, Bao Tran Thai, Kha Nguyen Cong, Thanh Ta Minh, Nghe Nguyen Thai (Tác giả)

  Tóm tắt | PDF | Lượt xem: 39 | Tải xuống: 0

  Recommender systems (RS) are widely used to reduce information overload by predicting user preferences and suggesting relevant items based on historical data. Many traditional methods rely heavily on user-item interaction data, which can be sparse and difficult to reuse when deployed to different data domains. In this paper, we build a semantic recommendation pipeline based on text content vector representations. The system proposes a method for matching text features by domain, then uses a large language model (LLM) to create vector embedding to encode descriptive information of items combining text fields according to each data domain and retrieves recommendations based on cosine similarity to improve recommendation quality and efficiency. The pipeline is applied to four data domains: Books, Magazines, Movies, and Beauty, all of which support thumbnails for visualizing the results.

• EVALUATION OF THE TOTAL POLYPHENOL CONTENT, TOTAL FLAVONOID CONTENT, ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF BOESENBERGIA PANDURATA RHIZOME EXTRACT

  Kiệp Đỗ Minh, Lãm Nguyễn Trường, My Ngô Nguyễn Trà, Thảo Trần Thanh, Vân Phan Cẩm (Tác giả)

  Tóm tắt | PDF | Lượt xem: 62 | Tải xuống: 0

  This study investigated the total polyphenol content (TPC) and total flavonoid content (TFC) as well as evaluated the antioxidant and antibacterial activities of the methanol extract of the Boesenbergia pandurata rhizomes. The results demonstrated that the methanol was rich in total polyphenol content and total flavonoid content, with the TPC and TFC values of 191.44 ± 5.66 mg GAE/g extract and 121.23 ± 3.82 mg QE/g extract, respectively. Furthermore, this extract also exhibited good antioxidant activity via the DPPH assay with the IC₅₀ value of 36.02 ± 0.13 mg/mL and it had strong antibacterial activity against Gram-positive strains, S. aureus, B. subtilis, and L. fermentum with the IC₅₀ values of 6.63 ± 0.41, 5.83 ± 0.35, and 9.18 ± 0.51 mg/mL, respectively. However, it was inactive with the Gram-negative strains, S. enterica, E. coli, and P. aeruginosa. Our findings suggest that B. pandurata rhizomes could be a promising source of the antioxidant and antibacterial activities.

• COOPERATIVE GOVERNANCE IN COMMUNITY-BASED TOURISM FOR SUSTAINABLE DEVELOPMENT: A COMPARATIVE CASE STUDY OF CON CHIM (VINH LONG) AND THIENG LIENG

  Hoang Thi Tham, Nguyen Thi Kieu Nga, Duong Duy Khanh (Tác giả)

  Tóm tắt | PDF | Lượt xem: 54 | Tải xuống: 0

  This study analyzes the current state of cooperative governance in community-based tourism development at Con Chim (Vinh Long), a context where community-based tourism models in Vietnam still face limitations in organizational and governance mechanisms. A qualitative approach is employed through in-depth interviews with key stakeholders, combined with a case study analysis. In addition, the community-based tourism model in Thieng Lieng (Ho Chi Minh City) is selected as a reference case to derive practical lessons. The findings indicate that the cooperative in Thieng Lieng plays a central role in coordinating activities, distributing benefits, and enhancing community capacity, whereas the cooperative at Con Chim still exhibits limitations in organizational structure, financial transparency, managerial capacity, and market linkages. Based on these findings, the study proposes an analytical framework for cooperative governance in support of sustainable development and offers policy implications for similar models.

• BLOOD CELL DETECTION AND CLASSIFICATION USING FASTER R-CNN, RETINANET, AND YOLOv12

  Quyen Nguyen Ngoc Hoang, Cang Phan Anh (Tác giả)

  Tóm tắt | PDF | Lượt xem: 36 | Tải xuống: 0

  Detection and classification of blood cells play an important role in supporting the diagnosis of hematological diseases by reducing errors associated with manual microscopic examination. In this study, we propose an automated system for detecting and classifying 13 types of peripheral blood cells from microscopic images based on three deep learning models, namely RetinaNet, Faster R-CNN, and YOLOv12. Experimental results demonstrate that YOLOv12 achieves the best overall performance with stable detection capability and effective balance across different blood cell classes. These findings highlight the potential of deep learning–based object detection models for automated blood smear analysis and hematological diagnosis.

• INVESTIGATION OF FACTORS AFFECTING EXTRACTION YIELD AND ANTIBACTERIAL ACTIVITY OF PIPER BETLE LEAF ESSENTIAL OIL WITH ESCHERICHIA COLI

  Tuong Nguyen Huy, Thai Do Quoc, Hao Pham Chi (Tác giả)

  Tóm tắt | PDF | Lượt xem: 0 | Tải xuống: 0

  The present study was conducted to evaluate the factors affecting the essential oil content obtained by steam distillation and to assess the antibacterial activity of betel leaf (Piper betle L.) essential oil against E. coli bacteria. The results showed that (i) the highest essential oil yield was 0.43% with the sample of pureed leaves soaked in warm water for 30 minutes, extracted for 120 minutes, with a 15% NaCl concentration, a 700 ml volume of water added to the flask, and at a temperature of 100°C; (ii) the main antibacterial components of betel leaf essential oil included phenolic and terpene compounds characteristic of betel leaf essential oil, most notably eugenol acetate (17.95%); (iii) betel leaf essential oil exhibited strong antibacterial activity against E. coli bacteria, where the 100% essential oil concentration resulted in the largest diameter of the inhibition zone.

• FACTORS INFLUENCING SAVING BEHAVIOR AMONG UNIVERSITY STUDENTS IN VINH LONG PROVINCE

  Nguyen Dang My Hanh, Nguyen Thi Hong Nga, Pham Phuong Mai, Tran Nguyen Tuyet Nhi (Tác giả)

  Tóm tắt | PDF | Lượt xem: 86 | Tải xuống: 0

  This study examines the factors influencing saving behavior among university students in the context of the growing importance of personal financial literacy for long-term financial stability. Data were collected from 314 students across various universities and analyzed using quantitative methods, including reliability testing, exploratory factor analysis (EFA), and ordinary least squares (OLS) regression. The results indicate that financial knowledge, financial attitude, and family influence have positive effects on students’ saving behavior, whereas peer influence exhibits a negative effect. Personal income also plays a significant role in promoting saving behavior. This study provides empirical evidence from Vietnam and offers policy implications for enhancing financial education among university students.

• EFFECT OF WATERCRESS POWDER ADDITION LEVEL ON PHYSICAL PROPERTIES AND SENSORY QUALITY OF COOKIES

  Tram Giap Pham Ngoc, Yen Tran Tieu, Phuc Tran Minh, Nhung Huynh Thi Hong, Mai Do Thi Tuyet (Tác giả)

  Tóm tắt | PDF | Lượt xem: 39 | Tải xuống: 0

  This study evaluated the effect of watercress powder incorporation (0–15%) on the physical properties and sensory quality of biscuits. A one-factor experimental design was applied with four treatments: a control without watercress powder and biscuits supplemented with 5%, 10% and 15% watercress powder. Watercress is convection-dried at 40°C, finely ground, mixed with flour, and used to prepare cookies according to a specific recipe. Biscuits were baked at 160°C for 40 min and analyzed for moisture content, water activity (a_w), color parameters (L*, a*, b*), spread ratio, cutting force, and sensory attributes. The results showed that increasing the level of watercress powder increased moisture content from 1.41% to 1.88% and a_w from 0.18 to 0.21, while the spread ratio decreased from 6.52 to 5.47. Cutting force increased from 18.36 N to 28.67 N, and biscuit color became darker, as indicated by a decrease in L* from 46.28 to 37.15. The overall acceptability score decreased from 7.87 to 6.73. The research results showed that 10% added watercress powde was suitable for biscuit production, improving both physical and sensory properties within acceptable consumer limits, with a moisture content of 1.62%, a_w 0.19, swelling capacity of 6.00, shear strength of 25.18 N, and preference score of 7.23. Therefore, the incorporation of 10% watercress powder is recommended for the production of value-added biscuits.