154092 research outputs found
Sort by
MO-SMAC:Multiobjective Sequential Model-Based Algorithm Configuration
No full textAutomated algorithm configuration aims at finding well-performing parameter configurations for a given problem, and it has proven to be effective within many AI domains, including evolutionary computation. Initially, the focus was on excelling in one performance objective, but, in reality, most tasks have a variety of (conflicting) objectives. The surging demand for trustworthy and resource-efficient AI systems makes this multiobjective perspective even more prevalent. We propose a new general-purpose multiobjective automated algorithm configurator by extending the widely-used SMAC framework. Instead of finding a single configuration, we search for a nondominated set that approximates the actual Pareto set. We propose a pure multiobjective Bayesian optimization approach for obtaining promising configurations by using the predicted hypervolume improvement as acquisition function. We also present a novel intensification procedure to efficiently handle the selection of configurations in a multiobjective context. Our approach is empirically validated and compared across various configuration scenarios in four AI domains, demonstrating superiority over baseline methods, competitiveness with MO-ParamILS on individual scenarios, and an overall best performance
Automation Support for Giving Feedback in Learning Programming by Doing
Get PDFProviding effective feedback on open-ended programming assignments is a challenge, particularly at scale. This challenge impacts student learning, as timely and accurate feedback is crucial to improve their programming and program design skills. We intend to develop an approach leveraging automation to support the feedback process, without requiring changes to assignments that enable full automation. This method aims to improve the consistency and efficiency of giving feedback, helping students learn more effectively.</p
Synergistic effect of Hypoxic Conditioning and Cell‐Tethering Colloidal Gels enhanced Productivity of MSC Paracrine Factors and Accelerated Vessel Regeneration (Adv. Mater. 3/2025):Graphical Abstract
Get PDFMesenchymal stem cells tethered to mechanically robust oxygen-generating injectable colloidal hydrogel significantly increased the secretion of various angiogenic cytokines and a chemokine that induced anti-inflammatory responses, reduced cellular apoptosis, and improved blood flow restoration and muscle regeneration in ischemic diseases. More details can be found in article number 2408488 by Mark W. Feinberg, Su Ryon Shin, and co-workers
The Role of SOX17 in the Shear Stress Response of the Arterial Endothelium
Get PDFBackground: Pulmonary arterial hypertension (PAH) is a fatal lung disease characterized by pulmonary vascular remodeling. Recently, genetic variations in SOX17 were shown to worsen the PAH phenotype and accelerate disease progression. Although SOX17 is a well-known embryonic endothelial-specific transcription factor that contributes to arterial differentiation and angiogenesis, its function in the adult vasculature is unclear. We hypothesized that SOX17 reinforces the arterial endothelium under fluid shear stress to protect against damage, and that impaired SOX17 expression predisposes the pulmonary vasculature for PAH development.Methods & Results: SOX17 expression was higher in healthy pulmonary artery endothelial cells (PAECs) as compared to pulmonary microvascular endothelial cells (MVECs). Expression of SOX17, but not related members of the SoxF family SOX7 or SOX18, increased two-fold when PAECs were subjected to 72 hours of 15 dyn/cm2 of fluid shear stress. SOX17 depletion using short hairpin RNA (shRNA) resulted in increased cell size, and significantly reduced elongation in the flow direction. Reducing SOX17 expression induced gap formation between cells both under static and shear conditions, and Electric Cell-Substrate Impedance Sensing (ECIS) of SOX17-depleted PAECs showed a reduction in barrier integrity. In line with this impaired barrier function, we found reduced levels of VE-cadherin upon depletion of SOX17, a phenotype that could be reproduced in a 3D vessel-on-a-chip model as well. Next to VE-cadherin, RNA expression of cell-cell adhesion proteins like β-catenin and ESAM were strongly reduced in SOX17-depleted PAECs. Regenerative capacity was disturbed, as indicated by a significant reduction in the number of Ki67-positive cells in a scratch assay and decreased RNA expression of cell cycle markers CyclinD1 and CyclinE1. Mechanistically, we identified the endothelial-secreted molecular guidance cue Semaphorin 3G (SEMA3G) downstream of SOX17, and found that addition of SEMA3G to SOX17-depleted PAECs could rescue the phenotype and recovered the expression of VE-cadherin at the adherens junctions.Conclusion: The presence of SOX17 is crucial for the maintenance of the cell junctions and barrier integrity under fluid shear stress. Impaired SOX17 expression could sensitize the arterial endothelium to damage, contributing to the pulmonary vascular remodeling observed in PAH.Figure legend: Upon SOX17-depletion, gaps form between the endothelial cells with fluid shear stress. The size of these gaps ranges from a mild to a more severe phenotype, depending on which primary donor is used. Both the total gap area and the number of gaps is significantly increased in the SOX17-depleted PAECs
The relationships between online vigilance, mental health, stress, and fear of missing out:A cross-sectional study
No full textBackground: The role of social media in daily life has been growing, especially during the COVID-19 pandemic. This has increased the problem of online vigilance (OV), which is a psychological connection towards social media, even when not actively engaging in it. Being online has previously been associated with adverse effects on mental health (MH). However, research on the effects of OV on MH, as well as related concepts like stress and fear of missing out (FoMO), is limited. Objective: The current study investigated the relationship between OV, MH, stress, and FoMO. The moderating effects of participants' age and gender were examined. Methods: 260 individuals participated in this cross-sectional online study, which contained the Online Vigilance Scale, Mental Health Continuum Short Form, Perceived Stress Scale, and Fear of Missing Out Scale. The data were analyzed using Spearman's rank correlation and (moderated) mediation analyses. Results: Findings indicate a negative association between OV and MH. Stress mediates this relationship, while evidence of FoMO being a moderator is lacking. No moderation effect of age or gender on the mediated relationship between OV and MH was found. Conclusion: This study significantly contributed to previous literature by elaborating on the relationships between OV, MH, stress, and FoMO. The findings can be utilised to raise awareness of the negative impacts OV can have on MH. Managing stress levels could reduce adverse mental health outcomes. Nonetheless, future research is needed to replicate the results to increase the generalisability and further validate the findings.</p
Postoperative delirium screening: Delirium observation screening scale versus single-channel EEG after cardiac surgery
Get PDFIntroduction / Purpose: Delirium in elderly patients following cardiac surgery is associated with increased complications and prolonged hospitalization. Early identification of delirium in high-risk patients is essential and is supported by an ERAS 1B recommendation. Although various screening tools are available, hypoactive delirium is frequently missed by nurse-reported assessments. In this study, we compared single-channel electroencephalography (SC-EEG) with the nurse-reported Delirium Observation Screening Scale (DOSS) for detecting postoperative delirium and assessing its impact on length of hospital stay after cardiac surgery.Materials and Method: In a prospective, quasi-experimental study conducted at the nursing ward, we compared DOSS screening (442 patients) and SC-EEG screening (462 patients) to identify postoperative delirium in cardiac surgery patients aged over 70 years. Definitive delirium diagnosis was made according to DSM-5 criteria, and analyses were adjusted for baseline differences using multivariable regression models. FindingsThe SC-EEG group demonstrated a higher delirium detection rate (20%) comparedto the DOSS group (14%) (p = 0.016) as determined with segmented linear regression. In unadjusted analyses, delirious patients identified via SC-EEG had a significantly shorter median hospital stay (p = 0.002). However, multivariable analysis showed that pneumonia and extended cardiopulmonary bypass time, rather than the screening method, were responsible for this difference (p = 0.54). In all patients, the SC-EEG-screened group had a 0.11-day shorter hospital stay (95% CI:-0.18 to -0.04) compared to the DOSS group (p = 0.002).Discussion / ConclusionThis new screening instrument SC-EEG screening showed an improved delirium detection rate following cardiac surgery. Although, it did not led to a reduction in length of stay among patients diagnosed with delirium, a modest reduction in length of stay for all patients with and without delirium in the SC-EEG cohort was found. These findings hightllight the potential value of objective delirium screening. The impact for clinical relevance should be further explored
2D sonar techniques for monitoring the canal bed morphology of entrances to navigation locks
Get PDFNavigation locks are essential components of inland waterways. They enabling vessels to traverse sections with differing water levels. These structures are increasingly vulnerable to damages caused by (1) scour i.e., erosion of sediment due to natural water flow and ship-induced currents, and (2) sediment or debris obstructing lock gates. Scour-induced damage threatens the structural integrity of locks, leading to costly maintenance, prolonged closures, and economic and environmental consequences. Traditional monitoring methods, including visual inspections and fixed instrumentation, are often hampered by water turbidity, high costs, and susceptibility to debris damage. Sonar technologies provide a non-invasive, cost-effective alternative for detailed underwater imaging, even in challenging environments. This paper explores the application of 2D sonar imaging for monitoring navigation lock approaches, with a focus on bed morphology and scour progression. Using the Prinses Beatrix Lock in the Netherlands as a case study, the paper demonstrates the effectiveness of 2D sonar systems in (i) detecting morphological changes such as scour and sediment transport from bed protection layers and (ii) estimating ship drafts. The findings underscore the importance of integrating sonar-based structural health monitoring systems to extend the lifespan of navigation locks, enhance safety, and optimize maintenance strategies for aging waterway infrastructure
Maxwell à la Helmholtz:Frequency-robust formulations for electromagnetic scattering by perfect conductors via Helmholtz integral operators
Get PDFLinear-Quadratic Optimal Control for Boundary Controlled Networks of Waves
Get PDFLinear-quadratic (LQ) optimal controls are computed for a class of boundary controlled, boundary observed hyperbolic infinite-dimensional systems, which may be viewed as networks of waves. The main results of this paper consist in converting the infinite-dimensional continuous-time systems into infinite-dimensional discrete-time systems for which the operators' dynamics are matrices, in solving the LQ-optimal control problem in discrete time, and then in interpreting the solution in the continuous-time variables, giving rise to the optimal boundary control input. The results are applied to two examples, a small network of three vibrating strings and a co-current heat-exchanger, for which boundary sensors and actuators are considered.</p
Periodic normal forms for bifurcations of limit cycles in DDEs
Get PDFA recent work [1] by the authors on the existence of a periodic smooth finite-dimensional center manifold near a nonhyperbolic cycle in delay differential equations motivates the derivation of normal forms. In this paper, we prove the existence of a special coordinate system on the center manifold that allows us to describe the local dynamics on the center manifold near the cycle in terms of periodic normal forms. To construct the linear part of this coordinate system, we prove the existence of time periodic smooth Jordan chains for the original and adjoint system. Moreover, we establish duality and spectral relations between both systems by using tools from the theory of delay and Volterra integral equations, dual perturbation theory, duality theory, and evolution semigroups.</p