Tạp chí Khoa học Trường Đại học Vinh

Enhancing network performance with improved random early de-tection

Vu Van Dien — Tue, 19 Aug 2025 10:03:34 +0700

Congestion has become an important issue affecting the performance of network systems. Active Queue Management (AQM) algorithms are crucial in ensuring network stability. The first active queue management technique deployed to control congestion was Random Early Detection (RED). RED compares the average queue length with predefined thresholds to mark or discard packets. DyRED [1] has improved RED based on changing the upper threshold. The author proposes an enhanced DyRED algorithm called ImRED (Improved DyRED) to enhance network performance further. Through simulation evaluation on the NS2, the author observed that ImRED outperforms DyRED regarding packet loss rate and average queue delay.

The agro-biological characteris-tics of some orange varieties, including BH, Bu Ha Tinh and Ron, grown in Quy Hop, Nghe An province

Tran Ngoc Toan — Tue, 19 Aug 2025 10:03:56 +0700

The research was carried out on three common orange varieties grown in the Quy Hop district, Nghe An province, including BH, Bu Ha Tinh and Ron, by using the questionnaire on the characteristics of 7-year-old orange varieties grown according to the production process of Nghe An Department of Agriculture and Rural Development. The results obtained on the agro-biological characteristics of 3 orange varieties named BH, Bu Ha Tinh and Ron, are the basis to help farmers understand the characteristics of orange varieties to identify, as well as provide scientific data for research institutions, management units in conservation, selection, production, supply and management of orange varieties in Nghe An province and the whole country.

Fixed point theorems for A-contractive mappings in bound-edly compact and T-orbitally compact metric spaces

Nguyen Huu Hoc — Tue, 19 Aug 2025 10:04:13 +0700

In this paper we prove some fixed point theorems for map-pings satisfying an implicit contractive conditions in metric spaces. Our re-sults improve and extend some results in the literature [6]. Some examplesare also given to illustrate our findings.

Gradient descent method and parameter selection for image restoration problem

Nguyen Dinh Dung — Tue, 19 Aug 2025 10:04:44 +0700

Image enhancement is a meaningful problem in many practical applications. It plays an important role in preprocessing steps for recognition and information extraction. Image restoration is often considered one of the data processing steps before the training process for machine learning models is performed. Image restoration problems are often solved by iterative algorithms, where the choice of iteration parameters plays an important role in improving the algorithm's convergence rate. The problem is determining the parameters that ensure the algorithm has the fastest convergence rate. In this paper, we propose a parameter selection method for the Gradient descent algorithm to recover the original image data from the image obtained after performing morphological transformation on the original image. According to this method, we analyze the eigenvalues of the morphological transformation matrix to derive a formula to determine the optimal parameters for the Gradient descent algorithm. We have proven that the iterative process converges from the parameter determination formula. The experimental results also show that the proposed theory is consistent and confirms that the approximate solution converges to the solution of the original problem.

A common fixed point theorem for mappings satisfying (E.A) - property via C-class functions in b-metric spaces

Tran Van An — Tue, 19 Aug 2025 10:05:08 +0700

In this paper, we give and prove a common fixed point theorem for mappings satisfying (E.A)-property via C-class functions and some its corollaries in b-metric spaces. Our results are generalizations of some given results. Also, an example is given to illustrate the obtained main result.

Finite convergence of the proxi-mal point method for solving equilibrium problems on Hada-mard manifolds

Nguyen Thi Thu — Tue, 19 Aug 2025 10:05:30 +0700

In this paper, we prove the finite convergence of sequences generated by (inexact and exact) proximal point methods for solving pseudomonotone equilibrium problems on Hadamard manifolds under the linear conditioning of the solution set.

Diversity of genus syzygium Gaertn. (Myrtaceae Juss.) in the North Central Region of Vi-etnam

Do Ngoc Dai, Le Thi Huong — Tue, 19 Aug 2025 10:06:16 +0700

This paper presents some research results on the diversity of the genus Syzygium in the North Central region of Vietnam from January 2022 to December 2023. There are 46 species belonging to Syzygium here; among 42 species that were collected and identified, 04 species were inherited from previous studies, and five species are newly recorded for the plant list of Central region of Vietnam. The stem forms of species are trees or shrubs, trees with 37 species and shrubs with nine species. The number of valuable plant species of the Syzygium is categorized as follows: 44 species supply essential oil (represented 95.65%), 32 species for timber (69.57%), 18 for edible and medicinal plants (39.13%).

Optimization of condition for methyl pheophorbide a formation and conversion to chlorin e6

Tue, 19 Aug 2025 10:07:15 +0700

Chlorin e6 is a stable chlorophyll derivative and can be used in photodynamic therapy (PDT) to treat cancer. One of the synthetic pathways of chlorin e6 is via the transformation of chlorophyll a to methyl pheophorbide a. In this study, we optimize the experimental condition for obtaining methyl pheophorbide a from chlorophyll extracted from Spirulina. The preliminary study showed that the suitable solvent system for extracting chlorophyll from the extract was dichloromethane and n-hexane in a ratio of 1:1. To determine the optimal parameters of 4 factors: time, temperature, chlorophyll/H₂SO₄ ratio (w/v), chlorophyll/MeOH ratio (w/v) to obtain the highest conversion efficiency of methyl pheophorbide a. The experimental matrix followed the Box-Behnken design to investigate the optimal region, with experiments for four factors at three levels to build the indicator surface. The optimal conditions for preparing methyl pheophorbide a from chlorophyll: Chlorophyll/H₂SO₄ ratio was 4/5 (w/v), chlorophyll/CH₃OH ratio was 6/50 (w/v), time was 4.4 hours and temperature was 44^oC. Chlorin e6 was successfully prepared from methyl pheophorbide a.

A note on matchings and regu-larity of graphs

Dao Thi Thanh Ha — Tue, 19 Aug 2025 10:07:40 +0700

Let be a simple graph. We introduce the notion of comb-match , and prove that reg comb-match +1. This improves some known bounds.

The results of culture snub-nose pompano (Trachinotus blochii Lacépède, 1801) in the “in Pond Raceway System” in Khanh Hoa province

Tue, 19 Aug 2025 10:08:39 +0700

The study aims to evaluate the environmental parameters and growth rate of snu-bnose pompano cultured in the “In Pond Raceway System - IPRS”. Fingerlings 5-6 cm in length were stocked at a density of 72 fish/m³ of 220 m³ raceway (22 m length x 5 m width x 2 m depth) and placed in a 10,500 m² pond (125 m in length x 84 m in width) and 2.5 m depth. Fish fed by commercial pellet food (slow sinking food) contented 45-48% of protein at 7 am (30-40%) and at 4 pm (60-70%) with the feeding rate of 5-7% per day for small fish and 2-5% per day for a bigger size. After 7 months of culture, the fish achieved an average weight of 753 g. The absolute growth rate (in weight) reached 3.4 g per day, the specific growth rate (in length) 0.1 cm per day and the survival rate of 96.6%, and the total biomass reached 11,574 kg, equivalent to the productivity of 52.6 kg/m³. This is an important step in the research and implementation of advanced technology in Khanh Hoa province and coastal culture areas to improve production and productivity per unit of water surface area.

Some results on the concept of {a_(m,n,i,j) }-stochastic domination for double arrays of random variables

Nguyen Thi Thanh Hien — Tue, 19 Aug 2025 10:09:02 +0700

In this paper, we prove some results on the concept of - stochastic domination for double arrays of random variables, where and are two sequences of positive integers and is sequences of positive constants satisfying... The main results establish double sum versions of Theorem 2.1 and Theorem 2.6 of Thành (2023).

Chemical compositions and cy-totoxic activity of essential oils extracted from Hedychium coro-narium J.Koenig grown in Vi-etnam

Tue, 19 Aug 2025 10:09:22 +0700

Hedychium coronarium, commonly known as white ginger lily (Zingiberaceae), is a native species in Asian forests. The plant has long been used as a traditional medicine for treating pain and inflammatory conditions and as a food-flavouring spice. In this work, the essential oil samples prepared from Hedychium coronarium leaves, rhizomes, and stems were analyzed by gas chromatography coupled with the mass spectrometry (GC/MS) method, which gave information on the main chemical components of leaf essential oil [β-pinene (27.90%), caryophyllene (23.93%), caryophyllene oxide (17.31%)], rhizome essential oil [β-pinene (29.56%), sabinene (12.05%), coronarin E (10.91%), p-cymene (10.39%), and α-pinene (10.06%)], and stem essential oil [α-phellandrene (18.71%), p-cymene (12.68%), β-pinene (12.18%)]. Three essential oils were also evaluated for their cytotoxic effects against SK-LU-1 cells (lung adenocarcinoma). The leaf essential oil was shown to be the most potent cytotoxic agent with an IC50 value of 80.19 ± 3.32 µg/mL. The cytotoxic activity against SK-LU-1 cells of the essential oils of Hedychium coronarium was reported for the first time. The results of this investigation indicated the similarities and differences among the chemical compositions of leaf, rhizome, and stem parts of Hedychium coronarium collected in Vietnam, which can be considered a potential and inexpensive resource of zingiberaceous essential oils.

Oroxylin A, as a potential inhibi-tor of rheumatoid arthritis: in silico experiment based on net-work pharmacology and molecu-lar docking.

Nguyen Thi Thuy Tram, Cao Hoang Minh Chau, Ngu Thi Tra Giang, Phan Thi Thuy — Tue, 19 Aug 2025 10:10:09 +0700

Oroxylin A is a potential inhibitory compound that could be applied to treat rheumatoid arthritis (RA). Rheumatoid arthritis is a chronic, systemic autoimmune disease that can lead to joint damage, deformity, and disability if not effectively treated. Current research utilizes network pharmacology and molecular docking methods to predict the primary mechanism of action of oroxylin A against rheumatoid arthritis. Through screening via protein-protein interaction networks (PPI), 67 potential RA-related targets have been identified, with EGFR, PTGS2, ESR1, MMP9, and GSK3B potentially serving as central targets. KEGG pathway analysis indicates that these 67 potential targets are associated with pathways related to metabolism, pathways in cancer, PI3K-Akt signalling pathway, Ras signalling pathway, and microRNAs in cancer. Molecular docking has been applied to determine the binding mode and affinity of oroxylin A with these five central RA-related targets. These findings offer the potential to inhibit relevant biological targets and provide a basis for further research into the mechanism of oroxylin A against RA.