Search Results (5,872)

Traditional Case-Based Reasoning (CBR) methods face significant methodological challenges, including limited information resources in case databases, methodologically inadequate similarity calculation approaches, and a lack of standardized case revision mechanisms. These limitations lead to suboptimal case matching and insufficient solution adaptation, highlighting critical gaps in the development of CBR methodologies. This paper proposes a novel CBR framework enhanced by generative AI, aiming to improve and innovate existing methods in three key stages of traditional CBR, thereby enhancing the accuracy of retrieval and the scientific nature of corrections. First, we develop an ontology model for comprehensive case representation, systematically capturing scenario characteristics, risk typologies, and strategy frameworks through structured knowledge representation. Second, we introduce an advanced similarity calculation method grounded in triangle theory, incorporating three computational dimensions: attribute similarity measurement, requirement similarity assessment, and capability similarity evaluation. This multi-dimensional approach provides more accurate and robust similarity quantification compared to existing methods. Third, we design a generative AI-based case revision mechanism that systematically adjusts solution strategies based on case differences, considering interdependence relationships and mutual influence patterns among risk factors to generate optimized solutions. The methodological framework addresses fundamental limitations in existing CBR approaches through systematic improvements in case representation, similarity computation, and solution adaptation processes. Experimental validation using actual case data demonstrates the effectiveness and scientific validity of the proposed methodological framework, with applications in risk assessment and emergency response scenarios. The results show significant improvements in case-matching accuracy and solution quality compared to traditional CBR approaches. This method provides a robust methodological foundation for CBR-based decision-making systems and offers practical value for risk management applications. Full article

Orthogonal Frequency Division Multiplexing (OFDM) modulation currently dominates the physical layer design in modern transmission systems. Its primary advantage is the simple reconstruction of channel frequency response (CFR). However, the Least Squares (LS) algorithm commonly used here is prone to significant estimation errors due to noise interference. A promising and relatively simple alternative is a DFT-based strategy that uses a pre-computed refinement/correction matrix to improve estimation performance. This paper investigates two implementation approaches for CFR reconstruction with pre-computed matrices. Focusing on multiplication operations, a threshold number of active subcarriers was identified at which these two implementations exhibit comparable numerical complexity. A numerical performance factor was defined and a detailed performance analysis was carried out for different guard interval (GI) lengths and the number of active subcarriers in the OFDM signal. Additionally, to maintain channel estimation quality irrespective of GI length, a channel impulse response (CIR) energy detection procedure was introduced. This procedure refines the results of the symbol synchronization process and, by using the circular shift property, preserves constant values of the precomputed matrix coefficients without system performance loss, as measured by Bit Error Rate (BER) and Mean Square Error (MSE) metrics. Full article

With the increasing demand for urban rail transit capacity, shield tunneling has become the predominant method for constructing underground metro systems in densely populated cities. However, the spatial interaction between shield tunnels and adjacent retaining structures poses significant engineering challenges, potentially leading to excessive ground settlement, structural deformation, and even stability failure. This study systematically investigates the deformation behavior and associated risks of retaining systems during adjacent shield tunnel construction. An orthogonal multi-factor analysis was conducted to evaluate the effects of grouting pressure, grout stiffness, and overlying soil properties on maximum surface settlement. Results show that soil cohesion and grouting pressure are the most influential parameters, jointly accounting for over 72% of the variance in settlement response. Based on the numerical findings, a Bayesian network model was developed to assess construction risk, integrating expert judgment and field monitoring data to quantify the conditional probability of deformation-induced failure. The model identifies key risk sources such as geological variability, groundwater instability, shield steering correction, segmental lining quality, and site construction management. Furthermore, the effectiveness and cost-efficiency of various grouting reinforcement strategies were evaluated. The results show that top grouting increases the reinforcement efficiency to 34.7%, offering the best performance in terms of both settlement control and economic benefit. Sidewall grouting yields an efficiency of approximately 30.2%, while invert grouting shows limited effectiveness, with an efficiency of only 11.6%, making it the least favorable option in terms of both technical and economic considerations. This research provides both practical guidance and theoretical insight for risk-informed shield tunneling design and management in complex urban environments. Full article

This study utilizes Ka-band millimeter-wave cloud radar (MMCR), assisted by a precipitation phenomenon instrument, to conduct case studies and analyses of convective precipitation, cumulus precipitation, and stratus precipitation in the Xi’an region. Using the Doppler spectral data of the MMCR, dynamic parameters such as vertical air motion velocity (updraft and downdraft) and particle terminal fall velocity within these three types of cloud precipitation were retrieved. The results show that above the melting layer, the maximum updraft velocity in convective clouds reaches 15 m·s⁻¹, and the strong updraft drives cloud droplets to move upward at an average velocity of about 5 m·s⁻¹. The average updraft velocity in cumulus clouds is greater than that in stratus clouds, with updrafts in cumulus and stratus mainly distributed within 1.5–3 m·s⁻¹ and 1–2 m·s⁻¹, respectively. The reflectivity factor of precipitation particles (Ze) is used to correct the equivalent reflectivity factor (Ka-Ze) after attenuation correction below the MMCR melting layer. The accuracy of calculating the raindrop concentration using the Ka-Ze of MMCR was improved below the melting layer. Based on the relationship between terminal fall velocity and particle diameter and using the conversion between the MMCR power spectrum and raindrop spectrum, the concentration, fall velocity, and particle diameter of raindrops are calculated below the melting layer. The results show that the average reflectivity factor, average concentration, and average particle diameter of raindrops follow the order of convective precipitation > cumulus precipitation > stratiform precipitation. However, the average terminal fall velocity distribution of raindrop particles follows a different order: convective precipitation > stratiform precipitation > cumulus precipitation. Full article

Peng–Robinson equation of state (PR EoS) has good prediction accuracy for phase diagrams of pure substances or mixtures, but liquid density, especially for high polar substances, is known to be ~20% lower value compared with experimental data at standard atmospheric temperature and pressure (SATP) conditions. To overcome this issue, translation via entropy-based solubility parameter (eSP) Peng–Robinson EoS (eSPT-PR EoS) is proposed in this work. The technique uses eSP for the liquid phase at SATP conditions and correlates the ideal value and a constant C for each substance as a correction. As a result, the C value can be linearly correlated with critical compressibility factor (Z_C). Finally, the liquid density was improved and gave an average relative deviation (ARD) value of 4.2% for the generally used 27 chemicals selected at SATP condition. Furthermore, critical density was also improved and gave ARD values of 3.9% compared with the original PR EoS of 21.8%. Thus, a universal calculation method based on PR EoS was developed for improving liquid density representation with the eSPT-PR EoS. Full article

Background: Tetralogy of Fallot is a congenital heart defect that requires early surgical correction. However, in developing countries, many patients undergo delayed treatment due to limited healthcare resources. This study aims to identify risk factors for postoperative complications in humanitarian patients undergoing late Tetralogy of Fallot repair, defined as surgery performed after 12 months of age. Methods: A retrospective analysis was conducted on 115 humanitarian paediatric patients with a median age of 1444 days (approximately 4 years) who underwent complete Tetralogy of Fallot correction. In this humanitarian programme, patients from developing nations underwent surgical repair at our tertiary referral centre in a high-resource country. Postoperative complications were monitored within the first 30 days after surgery. Two multivariable logistic regression models were used to analyse pre/perioperative (Model 1) and postoperative (Model 2) risk factors for complications. Results: Complications occurred in 24.3% of patients. No deaths were recorded. In Model 1, smaller pulmonary valve annulus (OR = 0.066; p < 0.01) and the use of right ventricle to pulmonary artery conduit (OR = 13.252; p < 0.01) were significantly associated with a higher risk of complications. In Model 2, prolonged invasive ventilation time (OR = 1.068; p < 0.01) and extended hospitalisation time (OR = 1.093; p = 0.04) were significantly associated with complications. Conclusions: Late surgical correction of Tetralogy of Fallot in humanitarian paediatric patients can be performed with low mortality but carries a significant risk of postoperative complications. The predictive models provide useful tools for proactive clinical monitoring, personalised management, and optimisation of hospital resources. Full article

The traditional radio wave propagation models exhibit several limitations when they are employed to predict the path loss for vehicular ultra-shortwave wireless communication. To addresses these challenges, an optimized approach for Egli model based on the high-resolution remote sensing satellite image is proposed in this study. The optimization process includes three components. First, a method for calculating the actual equivalent antenna height is introduced, utilizing high-precision remote sensing satellite imagery to obtain communication path profiles. This method accounts for the antenna’s physical length, vehicular height, and local terrain characteristics, thereby providing an accurate representation of the antenna’s effective height within its operational environment. Second, an equivalent substitution method for ground loss is developed, utilizing surface information derived from high-precision remote sensing satellite images. This method integrates ground loss directly into the Egli model’s calculation process, eliminating the need for separate computations and simplifying the model. Third, leveraging the Egli model as a foundation, the least squares method (LSM) is employed to fit the relief height, ensuring the model meets the requirements for ultra-short wave communication distances under line-of-sight (LOS) conditions and enhances suitability for real-world vehicular communication systems. Finally, the validity and accuracy of the optimization model are verified by comparing the measured data with the theoretical calculated values. Compared with the Egli model, the Egli model with additional correction factors, and the measured data, the average error of the optimized model is reduced by 8.98%, 2.09%, and the average error is 0.45%. Full article

Diaphragm springs, as critical components in commercial vehicle clutch assemblies, directly determine the clutch’s working performance. The design of diaphragm springs, which possess a distinct symmetrical structure that underpins their mechanical behavior, centers on obtaining the large-end nonlinear load–displacement curve—a typical large deformation-induced nonlinear problem. Traditional design relies on the A-L formula, but studies show finite element analysis (FEA) yields results closer to actual measurements. This study established an FEA model of the diaphragm spring’s disc spring (excluding separation fingers) and validated its correctness by comparing it with the A-L formula. Then, using FEA on models with separation fingers, it analyzed factors influencing the large-end load–displacement characteristics. Leveraging the inherent symmetry of the diaphragm spring structure, particularly the symmetrical distribution of separation fingers, the analysis process efficiently captures uniform mechanical responses during deformation, while this symmetric arrangement also ensures balanced load distribution during clutch operation, a critical factor for stabilizing the load–displacement curve. Results indicate the separation finger root is a key factor, with larger root holes, square holes (compared to circular ones), and more separation fingers reducing stiffness to effectively adjust the curve; in contrast, the tip and length of separation fingers have little impact, making the latter unsuitable for design adjustments. Full article

Urinary incontinence (UI) is a widespread worldwide gynecological pathology with a negative impact on women’s quality of life. We performed a narrative review and present a general, descriptive, and comprehensive perspective about surgical techniques for urinary incontinence in young women. Even though parity and vaginal births represent important risk factors for the occurrence of UI, it is also common among young women who are nulliparous. Lifestyle, obesity, smoking, alcohol consumption, and excessive stretching exercises can contribute to the occurrence of UI. Correct diagnosis and treatment may reduce the negative effects of UI on daily activities. Disease management varies depending on the three types of UI: stress, urge, and mixed. Conservative treatment involves lifestyle changes, pharmacological therapy, and pelvic floor muscle training. If symptoms persist, surgical techniques such as midurethral/suburethral slings, anterior colporrhaphy, and retropubic/laparoscopic colposuspension are necessary. Transvaginal tension-free vaginal tape obturator (TVT-O) is the most common surgical technique for the treatment of UI. Its effectiveness has been proven by reducing symptoms and improving quality of life. Alternative modern treatment methods are vaginal laser therapy, periurethral bulking agents injection, or local injection with autologous platelet-rich plasma. Surgical techniques for the treatment of UI are in continuous development and improvement considering the increased incidence of this pathology and the need of patients to improve symptoms and quality of life. Full article

Background/Objectives: The transcription factor 7-like 2 (TCF7L2) rs7903146 polymorphism has been strongly associated with type 2 diabetes mellitus (T2DM) in various populations; however, its impact on different ethnic groups is not fully understood. Given the distinct minor allele frequency in Chinese populations, this study aimed to analyze the association of rs7903146 with the risk of T2DM in a Han Chinese cohort and its relationship with relevant clinical parameters. Methods: We conducted a case–control study including 600 patients with type 2 diabetes mellitus (T2DM) and 511 sex-matched non-diabetic controls of Han Chinese descent. The TCF7L2 rs7903146 (C/T) polymorphism was genotyped using a TaqMan™ SNP assay. Clinical parameters, including body mass index (BMI), fasting plasma glucose, hemoglobin A1c, lipid profile, and high-sensitivity C-reactive protein (hs-CRP), were compared between genotypes. Logistic regression analyses were performed under a dominant genetic model (CT/TT vs. CC), adjusting for age, sex, systolic and diastolic blood pressure, BMI, and smoking status. Subgroup analyses were conducted by sex, BMI category, age at diagnosis, and family history of T2DM. Given the exploratory nature of this study and the low frequency of the TT genotype, no formal correction for multiple testing was applied. Results: Frequencies of the CT and TT genotypes were higher in the diabetic group (p = 0.045) and were significantly associated with an increased risk of T2DM under a dominant genetic model (adjusted OR = 2.24, p = 0.025). Individuals with CT/TT genotypes had elevated fasting glucose and hs-CRP levels; these genotypes were also linked to higher BMI in the female T2DM patients. The T allele frequency varied across ethnic groups, being lowest in East Asians and highest in Latin (Brazilian/mixed ancestry) populations. Mechanistically, the T allele may contribute to T2DM via altered TCF7L2 expression, impaired insulin secretion, inflammation, and metabolic dysregulation. Conclusions: The TCF7L2 rs7903146 T allele was associated with an increased risk of T2DM and higher fasting glucose and hs-CRP levels in this Han Chinese cohort. The CT/TT genotypes were also associated with higher BMI in the female T2DM patients. While the findings are consistent with the known effects of this variant in other populations, mechanistic hypotheses such as the involvement of inflammatory or metabolic pathways remain hypothetical and warrant further functional validation. Full article

Fault-tolerant control for bionic robotic fish presents significant challenges due to the complex dynamics and asymmetric propulsion introduced by joint failures. To address this issue, this paper proposes a fault-tolerant following control framework for multi-joint bionic robotic fish by combining fuzzy control methodologies and dynamic model correction. Firstly, offline fault analysis is conducted based on the dynamic model under multi-variable parameter conditions, quantitatively deriving influence factor functions that characterize the effects of different joint faults on velocity and yaw performance of the robotic fish. Secondly, an adaptive-period yaw filtering algorithm combined with an improved line-of-sight navigation method is employed to accommodate the motion characteristics of bionic robotic fish. Thirdly, a dual-loop following control strategy based on fuzzy algorithms is designed, comprising coordinated velocity and yaw control loops, where velocity and yaw influence factors serve as fuzzy controller inputs with expert experience-based rule construction. Finally, extensive numerical simulations are conducted to verify the effectiveness of the proposed method. The obtained results indicate that the bionic robotic fish can achieve fault-tolerant following control under multiple fault types, offering a valuable solution for underwater operations in complex marine environments. Full article

This study presents a novel design for emulating wheelset curving dynamics by implementing a laterally constrained wheelset and two independently powered rollers. The new configuration extends the test capability of the existing Virginia Tech-Federal Railroad Administration (VT-FRA) roller rig from a single wheel to a wheelset (i.e., two wheels). The redesigned rig is intended for evaluating both the tangent track and curving dynamics of a wheelset on a railcar. Test data from earlier experiments with a single wheelset is analyzed to assess the control system’s ability to maintain the commanded roller speed. This evaluation determines whether the new system can accurately emulate curves. The study develops correction factors to account for the dissimilar contact patch sizes and longitudinal creep forces resulting from the dissimilar roller diameters. A novel force measurement method is proposed to resolve the creep forces at each contact patch independently. An assessment of the existing VT-FRA roller rig data indicates a maximum roller speed deviation of 0.37% from actual values, which is deemed to be within the intended accuracy for future tests with the redesigned rig. An analysis of the force measurements by a load platform demonstrates the feasibility of accurately determining the wheel–rail contact forces for the new design rig, identical to the original design. Despite the numerous challenges in integrating a new wheel and roller into the existing VT-FRA roller rig, the study demonstrates that such a redesign can be achieved within the space and kinematic constraints, while maintaining the intended measurement accuracy. Full article

Volatile organic compounds (VOCs) are common indoor air pollutants known to pose significant health risks, yet little is known about how internal exposure varies across populations and environments. This study investigated the associations between indoor air pollutants and urinary VOC biomarkers in a nationally representative sample. We analyzed data from 1880 adults in the eighth Korea National Health and Nutrition Examination Survey (2020–2021) who completed an indoor air quality (IAQ) survey and provided urine samples, assessing the influence of sociodemographic, behavioral, and environmental factors. Indoor concentrations of PM_2.5, CO₂, formaldehyde, total VOCs, benzene, ethylbenzene, toluene, xylene, and styrene were measured, alongside the urinary concentrations of nine VOC biomarkers. Associations between pollutants, sociodemographic variables, and biomarkers were evaluated using univariate and multivariable linear regression with Bonferroni correction. Older age, female, lower socioeconomic status (SES), and smoking were associated with higher urinary VOC biomarker concentrations, with smoking showing the strongest associations. Indoor ethylbenzene, styrene, benzene, and CO₂ were also associated with multiple metabolites. These findings indicated significant associations between household air pollutants and urinary VOC metabolites, with disparities by age, sex, SES, and smoking status, underscoring the importance of targeted IAQ interventions for vulnerable populations. Full article

Spatial navigation involves the use of external (allocentric) and internal (egocentric) processing. These processes interact differentially depending on age. In order to explore the effectiveness of these interactions in different age groups (study 1), we compared the performance of children and adults in a two-session spatial maze task. This task was performed under deprived vision, thus preventing visual cues critical for allocentric processing. Number of correct performances and performance time were recorded as outcome measures. We recruited thirty healthy participants for the children (mean age 10.97 ± 0.55) and the adult (mean age 21.16 ± 1.76) groups, respectively. The results revealed a significantly higher number of correct actions and shorter performance times during maze solving in children compared to adults. These differences between children and adults might be due to developmental and cortical reorganization factors influencing egocentric processing. Assuming that activation of the posterior parietal cortex (PPC) facilitates egocentric spatial processing, we applied excitatory anodal tDCS over the right PPC in a second study with a different healthy adult group (N = 30, mean age 21.23 ± 2.01). Using the same spatial navigation task as in study 1, we evaluated possible performance improvements in adults associated with this neuromodulation method. Compared to a sham stimulation group, anodal tDCS over the right PPC did not significantly improve spatial task performance. Full article

Background: Examining medico-legal cases within hospitals aids in identifying care-related problems, facilitating necessary corrections and emphasizing successful preventive measures. The case of Meyer Children’s Hospital is particularly noteworthy as it offers insights into the evolution of litigation in regard to a tertiary pediatric hospital. Methods: The study sample comprised 158 malpractice claims received by Meyer Children’s Hospital from 1 January 2010 to 31 December 2023, which were managed by the Claims Management Committee (CMC) responsible for civil liability within the hospital. In this observational retrospective study, the following variables were analyzed: (1) The characteristics of the patients (age–sex) and the manner in which they interacted with the hospital, ultimately resulting in the compensation claim (method of access, area of specialty, outcomes based on the International Classification of Patient Safety (ICPS)). (2) Medico-legal factors: the details of the compensation claim, the significant issues noted in various cases, and the findings of the medico-legal inquiry conducted by the CMC. In cases of ADR (Alternative Dispute Resolution), we evaluated the nature of the procedure, the results, and the amount of compensation awarded. Results: We conducted a descriptive statistical analysis to delineate the trend of claims and identify specific deficiencies within structures or departments over time. Invasive procedures and surgical operations were identified as the leading causes of accidents, resulting in heightened mortality rates and serious injuries. The most common errors observed were diagnostic and therapeutic. Conclusions: The data that emerged highlighted a low rate of claims (11.28/year) and a low claim/service ratio (0.0002%), suggesting a high level of safety of patient care at the hospital. The acceptance rate (32%), the percentage of rejected cases (48/158~30% of total, or 48/99~49% of resolved claims), the average compensation (EUR 68,312), and the percentage of cases (92%) with judicial opinions consistent with those of the CMC indicate a tendency to pursue exploratory compensation requests and the effectiveness of CMC’s activity. Meanwhile, the predominant error types (surgical and diagnostic) are in accordance with national and international data. Finally, the scarcity of disputes concerning informed consent reflects the impressive effectiveness of the communication strategies utilized by the pediatricians at this center. Full article