https://dev.vojs.vn/index.php/jwree/issue/feed 2026-03-16T02:55:39+00:00 Open Journal Systems https://dev.vojs.vn/index.php/jwree/article/view/3 2026-03-13T07:32:57+00:00 Phu Hung Dinh

The fusion of infrared (IR) and visible images aims to generate a composite image that is both highly informative and visually optimized for human perception or computer vision applications. This paper presents an innovative fusion approach designed to enhance the effectiveness of this process. The method begins by utilizing the Fast Guided Filter (FGF) to decompose input images into base and detail components. An improved visual saliency map technique is introduced to efficiently fuse the base components, while a local energy-based fusion strategy is applied to the detail components. Experimental evaluations demonstrate that the proposed approach outperforms conventional methods, delivering superior results in both subjective and objective assessments.

2026-03-13T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/4 2026-03-13T07:42:15+00:00 Nguyet Anh Pham Thi Lan Huong Nguyen Tuan Minh Nguyen

Alcohol consumption is a cultural practice in many countries around the world, including Vietnam. Estimating alcohol consumption is essential for making public health recommendations. Wastewater-based epidemiology (WBE) is a tool that can help estimate alcohol consumption within a community based on information such as the concentration of the alcohol biomarker ethyl sulfate (EtS) in wastewater, the population residing in the area, and the wastewater flow rate. This study determined the flow rate of the Kim Nguu River and analyzed its water quality in November 2023. The results indicate that the water quality of the Kim Nguu River is poor, with daily loads of approximately 21.3 tons of COD, 9.6 tons of BOD5, 17.59 tons of TSS, 5.35 tons of TN, and 0.96 tons of TP. Based on EtS concentrations referenced from another study, the estimated alcohol consumption in Hanoi is approximately 2.61±0.33 mL/person/day. These findings contribute to the recommendations for wastewater treatment and environmental pollution reduction in Hanoi, while also providing a preliminary estimate of alcohol consumption among the city's residents, which can inform public health recommendations.

2025-12-17T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/6 2026-03-13T07:56:39+00:00 Ngoc Huy Nguyen Thi Minh Hai Le Thi Ly Nguyen Nam Giang Pham

In this paper, we investigate the existence and uniqueness of periodic mild solutions to the non autonomous Oseen-Navier-Stokes equations (ONSE) in the exterior domain 3R  of a rotating obstacle that is translating with a time-dependent velocity. Our method is based on the p q L L smoothness of the evolution family corresponding to linearized equations in combination with interpolation spaces and fixed-point theorems.

2025-03-13T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/7 2026-03-13T08:03:23+00:00 Thi Hue Hoang Thi Hong Hanh Nguyen Thi Thu Trang Bui Thi Hoai Thuong Nguyen

Domestic solid waste (DSW) management in mountainous areas faces significant challenges due to limited infrastructure and low levels of public awareness. This study aims to assess the awareness, attitudes, and behaviors of residents in three mountainous communes of Tuyen Quang province (Nhu Khe, Luong Vuong, and Cong Da) regarding the implementation of the 2020 Law on Environmental Protection, particularly provisions on DSW segregation and collection. Using a sociological survey of 660 households, the study analyzes the factors influencing residents' waste management behaviors through a theoretical framework, descriptive statistics, exploratory factor analysis (EFA), and multivariate regression. The results reveal that while local resident attitudes toward DSW management are generally positive, with 80% expressing agreement with the necessity of proper waste management, but knowledge of local resident remains limited, especially regarding the calculation of service fees under new regulations. Key determinants of behavior include perceived behavioral control, legal knowledge, and social influence. Based on these findings, the study proposes policy recommendations aimed at enhancing communication strategies, improving DSW management infrastructure, and strengthening community participation to increase the effectiveness of DSW management in mountainous regions.

2025-12-11T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/8 2026-03-13T08:10:03+00:00 Dat Tran Anh

Counterfeit agricultural products recognition poses a significant challenge due to the high visual similarity between genuine and fake items. Existing methods often struggle to capture the subtle details necessary for reliable differentiation. This paper presents Focus on Detail (FoD), a novel approach that emphasizes the automatic discovery of trustworthy 'authenticity cues' on the products. By employing custom-designed loss functions and a semi-supervised training strategy, FoD learns to suppress distracting background regions and focus exclusively on the most critical local features. Experimental results demonstrate that FoD achieves superior performance on standard benchmark datasets, establishing a new state-of-the-art in both accuracy and speed.

2025-03-13T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/10 2026-03-13T09:03:06+00:00 Viet Duc Nguyen

Antiwash high performance concrete (AHPC) is a specialized type of concrete used for construction projects where concrete needs to be placed below the waterline. With the aim to extend the service life of the hydraulic structures under water, this paper attempts to study on AHPC and its usage for rehabilitating the structure submerged in water. To do so, four AHPC mixtures have been involved in the experiment, in which superplasticizer dosages varied from 1% to 2% in conjunction with a specialized anti-washout admixture. Besides, a particular AHPC mixture would be used for repairing the structure by underwater concreting. The experimental results have shown that at fresh state the higher superplasticizer dosage, the higher slump flow of the AHPC mixtures, and the higher mixture mass loss inside the water. Meanwhile, at hardened state the higher superplasticizer dosage, the higher compressive strength gains. The single AHPC, which achieved slump flow of 20 cm and strength class of 50MPa, was chosen for successfully rehabilitating the structure submerged in water by mean of tremie method. The proposed future work could involve the study on mechanical performance of the concerned structure after rehabilitation.

2025-12-17T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/11 2026-03-13T09:10:29+00:00 Thi thu Hien Le Van Chien Nguyen Duc Thuat Hoang

Methodologies for cavitation prediction on high-head spillways: Review and propose a hybrid approachCavitation on high-head spillways can cause rapid concrete damage, posing serious threats to structural safety during flood releases. This review synthesizes methodologies for predicting cavitation inception, intensity, and damage risk across laboratory, field, numerical, and machine learning approaches. Both physical and numerical methods have been widely applied; however, they present limitations such as high cost, time consumption, and applicability restricted to individual case studies. The literature indicates that for spillways with similar configurations, the locations most at risk of cavitation damage are typically the same. Building on this insight, this study introduces a novel procedure for predicting cavitation risk by integrating advanced techniques including machine learning and 3D CFD modeling to develop a rapid prediction tool for quantifying the cavitation index.

2025-12-18T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/12 2026-03-13T09:24:54+00:00 Thi Lan Phuong Dinh Thi Thu Ha Tran

This study synthesized Fe-Ni bimetallic material from the guava leaf extract for the removal of copper (Cu) from wastewater. The material composition was characterized using EDS and FT-IR spectra. SEM images indicated that particle sizes ranging from 60 to 90 nm, confirming the nanoscale nature of the material. Batch adsorption experiments were conducted with an initial Cu concentration in solution of 5 mg/L. The results showed that Fe-Ni exhibited Cu removal capability, as evidenced by EDS and FT-IR analyses after the adsorption process. The removal mechanism was proposed to involve adsorption and reduction processes on the material surface. Optimal conditions were found to be pH 6, Fe-Ni dosage of 0.8 g/L, temperature of 25°C, contact time of 150 minutes, achieving a maximum removal efficiency of 79%. These results suggest that Fe-Ni synthesized from guava leaves is a friendly and low-cost adsorbent with strong potential for Cu removal in water treatment applications.

2025-12-11T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/13 2026-03-13T09:28:46+00:00 Tuan Thanh Le Nguyen Xuan Truong Nguyen Minh Thu Dao Linh Manh Pham

This paper presents a novel cloud-based architecture for multi-agent simulations, built on top of the GAMA platform, to address computational limitations of the traditional desktop-based version. We propose a distributed system leveraging the cloud computing model, pub/sub messaging, and containerized deployment to enable scalable, parallel execution of complex socio-environmental simulations, especially for pig farming. Experimental results demonstrate significant performance improvements, with the system supporting concurrent simulations across multiple worker nodes. The solution reduces infrastructure costs by 40% compared to physical implementation while providing researchers with an accessible web interface for scenario execution. This work establishes a reusable framework for cloud-based agent-based modeling, with particular applicability to smart agriculture and epidemic management.

2025-12-18T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/14 2026-03-13T09:32:39+00:00 Lan Do Nam Giang Pham Thi Ly Nguyen

In this paper, we consider the three-dimensional Kelvin-Voigt equations involving unbounded delays in a bounded domain Ω⊂ℝ. We will study the asymptotical stability of stationary solutions via the construction of Lyapunov functionals.

2025-12-11T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/15 2026-03-13T09:47:01+00:00 Truong Van Anh Huynh Thi Lan Huong Thi Nguyet Minh Hoang Kieu Duy Tran

Streamflow forecasting in small mountainous basins faces significant challenges due to non homogeneous and discontinuous observational data caused by sensor failures, irregular sampling, and missing records. This study presents a Long Short-Term Memory (LSTM) deep learning approach to handle discontinuous time series for water level forecasting in the Nam Pan River basin, northern Vietnam. The methodology integrates multiple data preprocessing techniques including linear and PCHIP interpolation, outlier removal, and Z-score normalization to address data irregularities. Input features comprise rainfall observations from multiple stations, lagged water levels (6–24 hours), and cyclical time encoding. The LSTM model achieves Nash–Sutcliffe Efficiency of 0.86–0.91 for 6-hour forecasts and 0.70–0.78 for 24-hour forecasts, with R² values of 0.88–0.94 and forecast assurance of 82–90%. Results demonstrate the model's robustness in handling imperfect data, confirming its applicability for operational flash flood early warning systems in data-limited mountainous catchments.

2025-12-17T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/16 2026-03-13T10:01:05+00:00 Quang Chieu Ta Dac Phuong Thao Nguyen Quang Minh Ngo Van Hung Hoang

Groundwater is essential for keeping the ecosystem in balance and meeting the water needs of homes, farms, and businesses, especially in big cities like Hanoi, which are strongly affected by climate change and overuse. In the context of climate change and overexploitation, accurate groundwater level forecasts not only help successful water resource management, but also serve as a foundation for long-term development. However, the intricacy, nonlinearity, and long-term dependency of groundwater levels present significant problems for standard approaches. Ours provides a novel approach for predicting groundwater levels at monitoring station Q64 in the Hanoi area using four deep learning models: RNN, LSTM, Transformer and Autoformer. We forecast short-term (48 hours), medium-term (120 hours) and long-term (360 hours). Experimental results reveal that Autoformer is clearly superior in forecasting situations and performs well in short-term, in the medium term forecasting. This demonstrates that the model based on an attention-based architecture ơan capture long-term properties of groundwater level time series. These findings support the use of deep learning in groundwater level forecasting, paving the way for the creation of intelligent forecasting systems, aiding decision-making in water resource management, and developing ways to adapt to climate change in large cities.

2025-12-19T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/17 2026-03-13T10:24:41+00:00 Van Dac Nguyen

In this article, we study an inverse source problem related to the generalized Rayleigh–Stokes equations on Hilbert scales, with weak-valued nonlinearities and memory effects depending on the history of the state function. We establish a representation of the mild solution and then investigate crucial properties of the associated resolvent operators. Based on these analyses, the existence result is obtained by applying Banach’s fixed-point principle. Finally, an illustrative example is provided to demonstrate the theoretical results.

2025-12-18T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/18 2026-03-13T10:32:42+00:00 Thi Thu Trang Bui Thi Hong Hanh Nguyen

This study investigates residents' awareness, attitudes, and behaviors concerning domestic solid waste management in Hanoi. Statistical analysis identifies "knowledge of domestic solid waste management" as the primary determinant of household waste segregation behavior. Consequently, it is recommended that the Hanoi municipal government implement targeted educational interventions to enhance environmental knowledge. Such measures are essential for promoting waste classification at the source, thereby minimizing environmental discharge and alleviating the operational burden on waste management authorities.

2025-12-18T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/19 2026-03-16T01:41:42+00:00 Ngoc Hung Nguyen Van Manh Nguyen Ngoc Linh Nguyen Tuan Anh Tran

This paper investigates a piezoelectric-electromagnetic hybrid energy harvester (PEM-HEH) which has only been developed recently where a linear electromagnetic harvester is attached to the free end of a cantilevered piezoelectric bimorph. First, the electromechanical model of PEM-HEH is introduced based on Euler–Bernoulli theory and Lagrange’s equations. It is demonstrated the coupling between the linear transverse motion of the piezoelectric bimorph and the nonlinear axial motion of the magnet inside the electromagnetic harvester. It turns out that the combination of two linear harvesters leads to a frequency-doubling effect in a nonlinear system. Next, a sample test is implemented to verify the characteristics of the nonlinearity of the system in phase portrait. Finally, relevant conclusions could be drawn.

2025-12-17T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/20 2026-03-16T02:06:05+00:00 Thanh Le Tran Thi Thoang Ta Thi Nguyet Minh Hoang Thi Thuong Nguyen

Permeability (K) is a fundamental parameter governing the design, construction, and operation of underground projects. Various methods have been developed to determine K; among them, estimation from grain size distribution is widely regarded as a simple and cost-effective approach. This study aims to estimate K from grain-size data using several empirical formulas applied to 14 samples collected during the hydrogeological-geotechnical investigations of the Van Cao-Hoa Lac metro project. The estimated K values were subsequently validated through two field pumping tests conducted at the corresponding boreholes with the purpose of identifying the most appropriate method for determining K. The mean K values obtained from different empirical methods varied by several orders of magnitude, with the Hazen method showing the closest agreement with those derived from pumping tests. The results indicate that grain-size-based formulas provide a reliable approach for evaluating aquifer permeability and offer valuable support during the preliminary design stage of the metro project.

2025-12-18T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/21 2026-03-16T02:13:40+00:00 Thi Phuong Mai Nguyen Dac Hai Do Ngoc Nhu Y Ho Gia Khiem Nguyen

The Vietnamese Mekong Delta (VMD), responsible for over half of Vietnam’s rice production and most of its aquaculture and fruit yields, is facing freshwater shortages due to intensified salinity intrusion (SI) and climate change impacts. This study integrates field measurements and MIKE 3D numerical modelling to analyze the spatial and temporal dynamics of salinity intrusion in the Dinh An branch of the Hau River. Results show that peak salinity concentration (Smax) typically occurs near the bottom, lagging 1–2 hours behind maximum water level during tidal cycles and 4-6 days in fortnightly tidal cycle during the neap–spring transition. The Dinh An estuary exhibits partial mixing with moderate stratification, with freshwater availability extending approximately 30 km inland during the dry season. The research results provide an important scientific basis for optimizing sluice gate operations to manage freshwater intake

2025-12-09T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/22 2026-03-16T02:17:47+00:00 Thanh Tung Hoang

The Cau River basin, particularly the segment flowing through Thai Nguyen province, is undergoing rapid urbanization and industrialization, leading to profound changes in land cover and adverse impacts on the hydrological regime. This paper presents a rapid assessment of these impacts using an integrated methodology that combines the analysis of statistical land use data from 2000-2020, remote sensing spatial data, and the SCS CN method. The results reveal an intense "concretization" process in new industrial centers like Pho Yen and Song Cong, where impervious surface areas have surged by 221% to over 458%, permanently converting more than 10,000 hectares of natural pervious land. This transformation has significantly increased the area-weighted Curve Number (CN) of the sub-basins (by up to 8%), leading to a drastic rise in the effective runoff coefficient (up to 167% for small rainfall events) and a massive increase in runoff volume during major storms. Spatial analysis has identified "hotspots" with the highest flood risk, concentrated downstream of industrial zones and in the low-lying areas of Thai Nguyen City. The study acknowledges limitations regarding hydraulic modeling of pipe networks but confirms that surface runoff generation has exceeded natural capacities.

2025-12-18T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/23 2026-03-16T02:20:54+00:00 Tien Quang Nguyen Van Anh Truong Le An Ngo Van Dai Hoang

Satellite-based monitoring of reservoir operations in transboundary, data-scarce basins remains a major challenge due to limited in situ observations and restricted data sharing. This study develops an end-to-end workflow on Google Earth Engine to monitor a cascade of nine Chinese reservoirs in the upper Da River and assess their influence on Viet Nam’s downstream Lai Chau reservoir. DEM-derived area–elevation–volume curves are generated from NASADEM and reservoir polygons, while a fast Sentinel-1 OtsuSmart classifier produces 7-day water-surface area series that are converted to water level and storage. Validation against survey curves for Lai Chau and Huoi Quang yields r = 1.00, with RMSE values of 1.86 and 0.23 km², respectively, while reconstructed Lai Chau water levels achieve r ≈ 0.80 and RMSE ≈ 5.6 m. Cascade and regulation indices along the Jupudu–Gelantan–Tukahe–Lai Chau chain show that Chinese operations exert first-order control on Lai Chau’s seasonal water-level regime, with positive correlations and 0–2-month lags at the monthly scale, while most net dry-season release originates from upstream branches. Daily lag-correlation analysis further reveals tight synchrony between Gelantan and Tukahe but a compensating, one-week out-of-phase response at Lai Chau, indicating active buffering. The framework uses only global open data and is transferable to other transboundary basins.

2025-12-17T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/25 2026-03-16T02:31:58+00:00 Tuan Anh Nguyen Duc Ngoc Nguyen Thang Binh Hoang Thi Hien Duong

This paper presents the design of a robust control mechanism that integrates the Super-Twisting Sliding Mode Control with a fuzzy logic scheme (FSTSMC). The selected control law mitigates chattering effects while maintaining a simple structural form. The theoretical stability of the closed-loop system is examined using Lyapunov criteria to guarantee convergence. The control parameter is adjusted through a fuzzy mechanism with two inputs to improve the system’s adaptability to parameter uncertainties, which are typically neglected in conventional control law design. Numerical simulation results demonstrate that the proposed controller achieves superior tracking performance compared with conventional SMC. Specifically, the Root Mean Square (RMS) tracking error does not exceed 0.04% in the absence of parameter uncertainties and remains below 3.55% when uncertainties are considered, except for the motor current (5.867%). In addition, the proposed scheme significantly suppresses chattering, which is still seen in conventional SMC.

2025-12-17T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/26 2026-03-16T02:40:48+00:00 Van Si Do Bich Ngoc Nguyen Thi Hong Nguyen Van Hiep Tran

Residual stresses significantly influence the mechanical performance and dimensional accuracy of metal components fabricated via additive manufacturing. This study investigates the residual stress fields and tensile properties of thin-walled specimens produced by metal 3D printing using stainless steel SS316L. Residual stresses were characterized through both numerical simulations and experimental measurements employing the hole-drilling method. Tensile testing was conducted to evaluate the effect of residual stresses on mechanical strength. Results indicate a strong correlation between the residual stress distribution and tensile behavior of SS316L specimens. The difference between the residual stress simulation and the measured experiment is 10%. The findings provide valuable insights for optimizing additive manufacturing parameters to enhance the structural integrity and reliability of metal 3D printed parts.

2025-12-02T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/27 2026-03-16T02:46:49+00:00 Van Thinh Le

This study applies Principal Component Analysis (PCA) to identify and quantify the dominant factors influencing soil erosion in the Da River Basin, Vietnam. Using the Revised Universal Soil Loss Equation (RUSLE) and long-term hydro meteorological, soil, and land use data, ten key parameters were analyzed. PCA reduced these interrelated variables to four principal components explaining 77.3% of total variance. The first component, accounting for 36.7%, highlights rainfall erosivity, precipitation, and sand content as primary drivers of erosion. The second and third components represent the effects of slope, soil erodibility, and silt content, while the fourth reflects the influence of land management and conservation practices. Regression analysis confirmed a strong positive association between rainfall–soil texture interactions and erosion intensity.

2025-12-12T00:00:00+00:00 Copyright (c) 2026 https://dev.vojs.vn/index.php/jwree/article/view/28 2026-03-16T02:55:39+00:00 Ngoc Thang Thai Van Chinh Le Ngoc Toan Bui

This study validates the measurement model of factors influencing the adoption of Building Information Modeling (BIM) in construction project management in Vietnam using Confirmatory Factor Analysis (CFA) with a sample of 200 experts. Six latent constructs were examined, including Institutional - Policy, Human Resources, Management, Technology, Economics, and Environment. The results indicate that the measurement model achieved a good overall model fit (χ²/df = 1.925; GFI = 0.901; CFI = 0.932; TLI = 0.918; RMSEA = 0.054). The measurement scales demonstrated satisfactory composite reliability (CR ≥ 0.89), convergent validity (AVE ≥ 0.57), and discriminant validity. This research contributes a statistically validated measurement instrument tailored to the Vietnamese context, providing a solid academic foundation for subsequent causal relationship analyses in future studies.

2025-12-12T00:00:00+00:00 Copyright (c) 2026