Search Results (3,534)

Motorcycle-dominated mixed traffic challenges vehicle-behavior modeling because motorcycles and cars differ in footprint, maneuverability, and longitudinal speed regulation. This study used roadside-video trajectories from six arterial sites in Hanoi, Vietnam. The trajectory pipeline produced 202,296 valid vehicle records, and the primary analysis included 158,821 motorcycles and 38,175 private cars. A focused manual identity-continuity audit of two 30 s clips yielded overall MOTA values of 0.9938 and 0.9977 and IDF1 values of 0.9931 and 0.9932. Motorcycles traveled faster on average but showed more stable longitudinal speed profiles: motorcycle speed standard deviation was 45% lower than the car value, and motorcycle coefficient of variation was less than half the car value. The directions of the mean-speed, speed-standard-deviation, and coefficient-of-variation contrasts were consistent across all six sites. Diagnostic reruns using lower speed bounds of 0–5 km/h and minimum trajectory lengths of 10–30 frames retained the same motorcycle–car stability direction ($r_{\mathrm{rb}}=-0.759$ to $-0.643$ for speed standard deviation and $-0.828$ to $-0.728$ for coefficient of variation). A three-component Gaussian mixture model was retained as a parsimonious engineering partition. Repeated-subsample stability was excellent for motorcycles (median adjusted Rand index, ARI, 0.970) and moderate for cars (median ARI 0.706), while mean maximum posterior probabilities exceeded 0.93 for both classes. Savitzky–Golay smoothing substantially increased usable acceleration coverage, but the inferred class contrast changed with the smoothing window; acceleration was therefore excluded from the primary clustering. A high-speed/high-variability rule flagged 4.62% of cars and 0.58% of motorcycles. This rule is an operational kinematic-screening heuristic, not a crash-probability model. The results provide class-specific evidence for mixed-traffic simulation calibration and cautious operational screening under the observed Hanoi arterial conditions. Full article

Lasiodiplodia theobromae is an important postharvest fruit rot pathogen that reduces the shelf life and marketability of durian. This study developed an ultrasound-assisted submicron curcumin-removed turmeric oleoresin and chitosan coating and evaluated its antifungal activity against L. theobromae in ‘Ri 6’ durian. An optimum formulation of 250 g L⁻¹ CRTO and 11.18 g L⁻¹ chitosan was obtained using response surface optimisation and prepared with ultrasound energy input of 384 J mL⁻¹. The optimised dispersion showed a hydrodynamic droplet size of 514 nm, a low polydispersity index of 0.16, a positive ζ-potential of +38 mV, and an emulsification efficiency of 86.16%; it retained one of the highest degrees of visual homogeneity among the 15 design formulations after 7 months of storage at 25 °C. In vitro assays showed strong dose-dependent inhibition of L. theobromae, with mycelial growth suppressed by 98.4–100% at 0.10 C₀ and 0.20 C₀; the two concentrations did not differ significantly (p > 0.05). Lesion development on wounded-inoculated fruit was reduced by 84.8–88.6% in CRTO–chitosan-coated fruit compared with the untreated control. Ultrasound-assisted submicron CRTO–chitosan coating is therefore a promising natural strategy for controlling postharvest fruit rot caused by L. theobromae in ‘Ri 6’ durian. The study was limited to one cultivar and one harvest batch, and postharvest quality, sensory attributes, and long-term dispersion stability were not assessed. Full article

Stand-up paddleboarding (SUP) at Sun Moon Lake, Taiwan, requires selective attribute prioritisation under operational and environmental constraints. This study develops a five-stage theoretical–procedural framework that organises participant needs through Schmitt’s experiential modules, classifies asymmetric quality functions using Kano analysis, links attributes to acceptable price and behavioural intention, and compares Kano-derived priorities with an evaluation–outcome priority matrix (EOPM). A quantitatively dominant sequential mixed-method design combined interviews with four operators and one certified coach, field observations, online reviews, and an electronic survey administered from 8 to 24 May 2023 to a purposive convenience sample of participants with prior SUP experience at Sun Moon Lake; 450 of 499 responses were usable (90.1%). Analyses included descriptive statistics, Kano classification, Satisfaction Improvement and Dissatisfaction Reduction Coefficients (SIC/DRC), 5000-resample bootstrap subgroup comparisons, correlation analysis, exploratory factor analysis, multiple regression, and the EOPM. Relaxation (SIC = 0.749) and happiness (SIC = 0.744) produced the largest satisfaction gains, whereas safety (DRC = −0.636) and shower facilities (DRC = −0.607) showed the strongest dissatisfaction sensitivity. Professional coaching (r = 0.349), skill instruction (r = 0.339), and safety (r = 0.331) were the strongest correlates of composite behavioural intention (Cronbach’s α = 0.941). Exploratory factor analysis identified experiential–relational enhancement and operational–competence support; both predicted behavioural intention (β = 0.174 and 0.296, respectively; adjusted R² = 0.182). The EOPM identified safety and skill instruction as strategic strengths, while professional coaching remained an improvement priority, illustrating partial convergence between asymmetric quality and outcome-based prioritisation. The framework supports selective investment in non-negotiable operational foundations and high-leverage experiential enhancements in eco-sensitive sport tourism. Full article

This study examines how retailers’ in-store green promotion influences consumers’ repurchase intention toward green food products in Vietnamese supermarkets. Although prior research has examined green perceived value, green trust, and green purchase intention, less is known about how retailer-driven promotion at the point of purchase is associated with repeat purchase decisions, particularly through value-based and trust-based mechanisms in emerging market supermarket settings. Drawing on signaling theory and consumption value theory, the study conceptualizes in-store green promotion as a set of retailer-provided signals that help consumers evaluate credence attributes of green food, and develops a model in which green trust and four dimensions of green perceived value—emotional value, conditional value, functional value, and social value—mediate the relationship between in-store green promotion and repurchase intention. Data were collected through a survey of 412 consumers who had previously purchased green food products from supermarkets in Vietnam. The model was tested using confirmatory factor analysis and structural equation modeling. The findings show that in-store green promotion has a positive direct effect on repurchase intention and significantly enhances green trust and all four dimensions of green perceived value. Green trust and the four value dimensions also positively predict repurchase intention. Mediation analysis indicates that the effect of in-store green promotion on repurchase intention is transmitted through both green trust and multidimensional green perceived value. The study contributes to green marketing research by shifting attention from general green communication to retailer-driven in-store promotion and by explaining green food repurchase intention through integrated signaling-based, value-based, and trust-based mechanisms. Full article

Leakage identification in water distribution networks must estimate leak locations and magnitudes under demand fluctuations, similar adjacent-node responses, and superimposed multiple-leak signals. This study combines physics-based joint inversion with ExtraTrees candidate re-ranking. Using an EPANET model of the Hanoi network, emitter candidates were placed at pipe midpoints, and scenarios were generated across demand periods, global demand factors, and four regional demand fluctuations. Sixteen pressure residuals and 22 flow residuals formed the observation vector. The physical stage enumerated zero- to three-leak combinations and used bounded least squares to estimate leakage flows and demand corrections; standardized pressure-flow residuals and penalty terms produced the candidate pool. ExtraTrees then re-ranked candidates using candidate structure, physical scores, flow statistics, and operating-period features. In 2000 independent blind-test scenarios, complete localization accuracy, leak-number identification accuracy, and total leakage-flow MAE were 90.55%, 97.10%, and 0.841 L/s; for 1500 leakage scenarios, they were 87.53%, 96.27%, and 1.117 L/s. Re-ranking increased leakage-scenario complete localization from 76.13% to 87.53%, while final candidate-pool recall reached 99.15%. Robustness tests involving measurement noise, hydraulic-model mismatch, sensor density, computational time, and Net1 indicated that the method improves candidate discrimination under simulation, although roughness bias and weak multiple-leak signals remain challenging. Full article

Accurate segmentation of non-small cell lung cancer (NSCLC) on positron emission tomography/computed tomography (PET/CT) is an essential prerequisite for automated metabolic tumor volume (MTV) quantification and staging. Although deep learning models achieve high performance on large-scale datasets, their generalization across different clinical domains is limited by variations in imaging protocols and patient demographics. This study aims to evaluate several deep learning architectures and investigate a transfer learning strategy to mitigate domain shift. Three architectures, including ResNet-backbone 3D U-Net, nnU-Net v2, and Swin UNETR, were benchmarked from scratch and compared with a fine-tuned nnU-Net initialized with AutoPET II weights. Results on the internal dataset showed that the fine-tuned nnU-Net achieved a Dice similarity coefficient (DSC) of 83.4 ± 6.5%, a 95% Hausdorff distance (HD95) of 5.1 ± 3.6 mm, and a precision of 89.6 ± 8.2%. Compared to the nnU-Net v2, the fine-tuned nnU-Net improved the absolute DSC by 6.8% while reducing local training time by 37.5% by bypassing the initial feature-learning phase. The fine-tuned nnU-Net model also demonstrated a high correlation between the MTV and the ground truth (Pearson r = 0.96, p < 0.001), indicating its potential as a reliable automated approach for quantitative MTV extraction and NSCLC prognostic-related analysis. Full article

Polyhydroxyalkanoates (PHAs) are biodegradable microbial polyesters that may reduce dependence on petroleum-derived plastics, but broader use remains constrained by production costs and tightly controlled cultivation. Thermophilic microorganisms have attracted increasing attention as promising PHA producers because they can be cultivated at elevated temperatures, reducing contamination risks and operational costs. In this study, a thermophilic Geobacillus sp. strain SL28 isolated from a Vietnamese hot spring was evaluated for its PHA-producing capability. Temperature, initial pH, carbon and nitrogen sources, C/N ratio, and cultivation time were examined. Intracellular inclusions were assessed by Sudan Black B and Nile Blue A staining and transmission electron microscopy, whereas the recovered polymer was characterized by FE-SEM, Fourier-transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), ¹H- and ¹³C-nuclear magnetic resonance (NMR) spectroscopy, capillary viscometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. Under the optimized cultivation conditions identified by one-factor experimentation (50 °C, pH 7.0, sucrose, peptone, C/N 25:1, and 72 h), SL28 reached a dry cell weight of 2.215 ± 0.16 g/L and a PHA concentration of 1.383 ± 0.04 g/L, equivalent to 62.57 ± 2.82% of DCW. Structural characterization confirmed that the recovered polymer was poly(3-hydroxybutyrate) (PHB). The purified PHB also exhibited favorable thermal stability, a relatively high molecular weight, and satisfactory mechanical properties. These results demonstrate the potential of thermophilic Geobacillus sp. SL28 as a promising candidate for PHB production. Full article

Smart home provision faces many challenges, resulting from the growing demand for monitoring smart home services in uncertain environments, such as rural areas, and regions with high humidity, pollution, and unstable electricity supply. Effective data processing in decision-support cyber–physical systems for smart environments is challenging given that the raw data [collected from context-aware networked sensor-based systems under dynamic uncertainty] is typically imprecise, inaccurate, and potentially incomplete. Addressing this challenge requires effective data processing. To address this challenge, in this paper we present our proposed novel Fuzzy Knowledge Graph Model to enable the processing of raw data derived from a smart home environment. The experimental testing of the proposed model includes data preparation, reasoning, and action control. To evaluate the performance of the proposed model we utilise four evaluation metrics: accuracy, precision, recall, and F1-score. The evaluation shows that the proposed model achieves good statistically significant results in terms of accuracy (recall: 100% with low false positives; precision: 94.74%), leading to an F1-score of 97.3%. The results indicate that the proposed model demonstrates high levels of performance in terms of accuracy, with good precision, recall, and F1-score. Moreover, the reported results confirm the reliability, stability, efficacy, and utility of our proposed model, which we posit has the capability to be generalised to smart home domains. Full article

This study explored the microbial diversity of Vietnamese cocoa fermentation and the antifungal potential of indigenous bacteria. Cocoa beans were collected from three Vietnamese regions at different fermentation stages. Bacteria were isolated and identified using 16S rRNA gene sequencing. A total of 22 lactic acid bacteria (LAB) and 9 acetic acid bacteria (AAB) strains were identified, belonging to the genera Lactiplantibacillus, Limosilactobacillus, Levilactobacillus, Lacticaseibacillus, Pediococcus, Acetobacter, Gluconobacter, and Komagataeibacter. Four strains, including three LAB strains (L. plantarum L11E48, L. plantarum L15E48, L. brevis L8DN24) and one AAB strain (A. ghanensis G63E48), were evaluated for their ability to inhibit Aspergillus flavus and Fusarium foetens on agar media and bread. All strains demonstrated strong antifungal activity, inhibiting 51–100% mycelial growth of both fungi after 7 days of incubation. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of cell-free supernatant were 640 μL/mL against A. flavus and varied from 160 to 320 μL/mL against F. foetens. When applied in breadmaking, L. plantarum L15E48, L. brevis L8DN24, and A. ghanensis G63E48 delayed fungal growth for 1–2 days. These findings provide valuable baseline data on Vietnamese cocoa fermentation microbiota and highlight the potential of indigenous LAB and AAB strains for biocontrol, food preservation applications, and starter culture development. Full article

Accurate rainfall information is essential for water-related hazard assessment in mountainous regions, where complex terrain and sparse gauge networks limit monitoring reliability. This study evaluated long-term rainfall characteristics and the performance of three satellite precipitation products—CHIRPS, GPM IMERG, and GSMaP—along the National Highway 6 corridor in northern Vietnam. Daily gauge observations from 11 meteorological stations with station-dependent records between 1961 and 2024 were used to characterize rainfall variability and heavy-rainfall frequency. Matched gauge–satellite records from 2001 to 2024 were evaluated using continuous statistical indicators, contingency-table metrics, empirical cumulative distribution functions, and percentile-based analysis. Data from 2025 were additionally examined as an extreme-rainfall case study, supplemented by visual gauge–satellite comparisons; however, these data were not used as an independent satellite-validation period. The long-term gauge records showed marked spatial variability in rainfall magnitude and threshold-exceedance frequency. In 2025, all 11 stations recorded daily rainfall exceeding 50 mm, while eight stations recorded events exceeding 100 mm. Satellite-product performance varied substantially among stations, rainfall thresholds, and evaluation metrics, and no product was uniformly superior. At the 100 mm/day threshold, the probability of detection ranged from 0.024 to 0.276, whereas the false alarm ratio ranged from 0.781 to 0.916. Upper-tail analysis showed contrasting product-specific behavior: at the 99th percentile, CHIRPS and GPM IMERG underestimated gauge rainfall by 20.95 and 8.95 mm, respectively, whereas GSMaP overestimated it by 35.57 mm. These findings demonstrate that local validation, uncertainty assessment, and application-specific adjustment are necessary before satellite precipitation products are used for flash-flood, rainfall-induced landslide, drainage-risk, and transportation-infrastructure assessments in mountainous regions. Full article

Offshore wind development in the Binh Thuan–Phu Quy offshore domain requires regional, multi-variable preliminary metocean screening that extends beyond wind-resource mapping alone. This study presents a 32-year integrated wind–wave–bathymetry screening of four representative offshore wind sites in the Binh Thuan–Phu Quy offshore domain, Vietnam, using hourly ERA5 reanalysis data (1993–2024) and GEBCO 2025 bathymetry. The sites span four water-depth classes: shallow nearshore (BT01, 27 m), bottom-fixed (BT02, 49 m), transitional (BT03, 81 m), and floating-suitable (BT04, 161 m). For the IEA Wind 15 MW reference turbine at 150 m hub height, mean wind speed increases from 7.71 m s⁻¹ at BT01 to 9.75 m s⁻¹ at BT04, gross single-turbine capacity factor from 46.7% to 62.2%, and gross annual energy production from 61.4 to 81.7 GWh yr⁻¹. Along the selected BT01–BT04 sequence, mean significant wave height increases from 1.06 m to 1.49 m, with P95 $H_{\mathrm{s}}$ rising from 2.15 to 3.27 m. The northeast monsoon (November–March) dominates both wind and wave energy at all sites, whereas the mildest sea states occur during the April–May transition months. These conditions identify April–May as having the lowest monthly mean sea states; monthly means alone do not define operational weather windows. Interannual variability of annual gross capacity factor is moderate, with coefficients of variation of 9.8–10.2%. The integrated screening matrix shows that wind resource, energy yield, water depth, and wave exposure increase together along the selected four-site sequence, without implying a causal depth relationship or a domain-wide trend: the highest-yield site requires a floating substructure under the most exposed conditions, whereas the most benign site yields the least energy. All reported values are gross, reanalysis-based screening indicators rather than bankable resource estimates. From a sustainability perspective, the framework supports balanced early-stage planning by considering energy yield together with depth and marine exposure, while its open, long-term datasets provide reproducible, comparatively low-cost decision support for data-scarce emerging offshore wind markets. It does not quantify lifecycle, ecological, social, or economic sustainability. Full article

The northern margin of the East Asian tropics harbors exceptional endemism, yet its freshwater fish fauna remains poorly characterized. Tachysurus virgatus, long considered a single widespread species in this region, exemplifies this taxonomic gap. Through integrative taxonomic analyses combining morphological and molecular evidence, we uncovered remarkable cryptic diversity within this species. Phylogenetic reconstructions reveal that true T. virgatus is restricted to the Wanquan River basin on Hainan Island, whereas nine additional lineages from other drainages represent previously unrecognized species described in this study. Together with two known congeners (T. spilotus and T. kyphus), these form the monophyletic T. virgatus species group for which we provide morphological diagnoses. Pronounced incongruence between morphological and molecular divergence characterizes this group, underscoring the necessity of integrative approaches for species delimitation in morphologically conserved lineages. Moreover, distinct habitat specialization patterns were identified within the group, with species exhibiting adaptations to three ecological niches: mainstem river, montane streams, and generalist habitats occupying both. Correlations between habitat preferences and functional morphology were preliminarily discussed. Using our revised taxonomic framework, we evaluated the conservation status of all species under IUCN Red List criteria, with several newly described taxa warranting threatened status due to extremely limited distributions. This study highlights the pervasive cryptic diversity of freshwater fishes in the north margin of East Asian tropics and emphasizes the critical importance of rigorous taxonomic resolution to guide effective conservation in this biogeographically complex region. Full article

Background/Objectives: Osteoporotic vertebral fractures (OVFs) can cause persistent pain and loss of independence. This study quantified impairment in basic and instrumental activities of daily living and identified independent cross-sectional correlates in postmenopausal women with OVFs. Methods: This cross-sectional analysis included 184 postmenopausal women from a 200-patient OVF cohort at a spine clinic in Vietnam. Functional status was assessed using the Barthel Index (BI) and Lawton Instrumental Activities of Daily Living (IADL) scale. Primary analyses used multivariable linear regression with HC3 robust inference; ordered-logistic and model-specification analyses assessed robustness. Results: Mean age was 69.95 ± 7.78 years and mean visual analog scale (VAS) pain score was 6.69 ± 1.58. Basic-activity dependence was present in 81.5% of participants (mean BI, 82.96 ± 16.45), and 66.8% had at least one IADL limitation (mean IADL, 5.84 ± 2.04). In the adjusted BI model, higher VAS pain intensity was the strongest observed correlate of poorer function (B = −7.996; β = −0.769; p < 0.001), and higher body mass index was associated with lower BI. In the adjusted IADL model, higher VAS pain intensity (B = −0.694; β = −0.538; p < 0.001) and older age were associated with lower scores. Ordinal sensitivity analyses confirmed the pain association, whereas the BMI finding was attenuated. Conclusions: Pain intensity was the strongest observed cross-sectional correlate of both functional domains. The findings support comprehensive functional assessment and hypothesis-driven longitudinal studies, but they do not establish that pain reduction will cause functional recovery. Full article

Background: Current evidence on the relationship between upper airway morphology and respiratory function remains inconsistent and inconclusive. Although anatomical narrowing is often linked to respiratory impairment, its effect on measurable pulmonary function in asymptomatic individuals has not been consistently demonstrated. Methods: This cross-sectional study included 50 healthy young adults who underwent cone-beam computed tomography (CBCT) and spirometry. Airway volume, minimum cross-sectional area (MCA), and computational fluid dynamics (CFD)-derived airflow parameters were analyzed. Associations between structural and functional variables were assessed using Spearman’s correlation. Results: Significant correlations were found among structural airway parameters, particularly between MCA and total airway volume (ρ = 0.8025, p < 0.001). However, no significant associations were observed between airway morphology and spirometric indices (FVC, FEV₁, MEF). Similarly, CFD-derived airflow velocity and pressure showed no correlation with pulmonary function. Conclusions: Within this cohort, no statistically detectable association was observed between upper airway morphology and pulmonary function, suggesting that structural assessment alone may not capture functional respiratory capacity in young, healthy adults. Given the cross-sectional design and sample size, this finding should be interpreted as an absence of a detectable association in this specific cohort rather than evidence against a relationship in the general population. Full article

This study proposes a comprehensive design framework for computer mice tailored to Vietnamese users, based on anthropometric data collected from 610 university students using a cross-sectional survey. Three important parameters—hand length, finger length, and palm width—were used to specify five optimal size groups with an overall satisfaction rate of 81.7%. The average hand length of 186 mm places Vietnamese users within the 20th–30th percentile of the U.S. population (ANSUR), suggesting that devices designed as medium-sized in Western markets may be oversized in Vietnam. Parametric modeling combined with Fitts’ Law and ISO 9241 produced geometrically precise designs that reduce discomfort at inclination angles of 25–30%, while also enabling the development of a user-friendly tool for selecting the most appropriate mouse size for consumers. Full article