TrustGuard: GNN-based Robust and Explainable Trust Evaluation with Dynamicity Support

Trust evaluation assesses trust relationships between entities and facilitates decision-making. Machine Learning (ML) shows great potential for trust evaluation owing to its learning capabilities. In recent years, Graph Neural Networks (GNNs), as a new ML paradigm, have demonstrated superiority in dealing with graph data. This has motivated researchers to explore their use in trust evaluation, as trust relationships among entities can be modeled as a graph. However, current trust evaluation methods that employ GNNs fail to fully satisfy the dynamicity nature of trust, overlook the adverse effects of attacks on trust evaluation, and cannot provide convincing explanations on evaluation results. To address these problems, in this paper, we propose TrustGuard, a GNN-based accurate trust evaluation model that supports trust dynamicity, is robust against typical attacks, and provides explanations through visualization. Specifically, TrustGuard is designed with a layered architecture that contains a snapshot input layer, a spatial aggregation layer, a temporal aggregation layer, and a prediction layer. Among them, the spatial aggregation layer can be plugged into a defense mechanism for a robust aggregation of local trust relationships, and the temporal aggregation layer applies an attention mechanism for effective learning of temporal patterns. Extensive experiments on two real-world datasets show that TrustGuard outperforms state-of-the-art GNN-based trust evaluation models with respect to trust prediction across single-timeslot and multi-timeslot, even in the presence of attacks. In particular, TrustGuard can explain its evaluation results by visualizing both spatial and temporal views

Switching Behavior to Cloud Enterprise Information Systems in China

Cloud computing has recently become a popular information technology in China. Several China’s enterprises tend to move from client/server enterprise information systems (EISs) to cloud EISs. However, few studies have addressed the switching issues. This study aims to investigate factors that affect switching behavior from client/server EISs to cloud EISs. The research model draws from technology-organization-environment framework. We collected data from top managers and owners of China’s enterprises to analyze six hypotheses. The results show that technological context (perceived security and compatibility), and environmental context (supplier support and consultant support) significantly influence switching behavior. The findings are useful for understanding switching issues from client/server EISs to cloud EISs

STPrivacy: Spatio-Temporal Privacy-Preserving Action Recognition

Existing methods of privacy-preserving action recognition (PPAR) mainly focus on frame-level (spatial) privacy removal through 2D CNNs. Unfortunately, they have two major drawbacks. First, they may compromise temporal dynamics in input videos, which are critical for accurate action recognition. Second, they are vulnerable to practical attacking scenarios where attackers probe for privacy from an entire video rather than individual frames. To address these issues, we propose a novel framework STPrivacy to perform video-level PPAR. For the first time, we introduce vision Transformers into PPAR by treating a video as a tubelet sequence, and accordingly design two complementary mechanisms, i.e., sparsification and anonymization, to remove privacy from a spatio-temporal perspective. In specific, our privacy sparsification mechanism applies adaptive token selection to abandon action-irrelevant tubelets. Then, our anonymization mechanism implicitly manipulates the remaining action-tubelets to erase privacy in the embedding space through adversarial learning. These mechanisms provide significant advantages in terms of privacy preservation for human eyes and action-privacy trade-off adjustment during deployment. We additionally contribute the first two large-scale PPAR benchmarks, VP-HMDB51 and VP-UCF101, to the community. Extensive evaluations on them, as well as two other tasks, validate the effectiveness and generalization capability of our framework

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

An investigation of patient decisions to use eHealth : a view of multichannel services

eHealth service has received increasing attention. Patients can consult online doctors via the internet and then physically visit the doctors for further diagnosis and treatments. Although extant research has focused on the adoption of eHealth services, the decision-making process from online to offline health services remains unclear. This study aims to examine patients’ decisions to use online and offline health services by integrating the extended valence framework and the halo effect. By analyzing 221 samples with online consultation experiences, the results show that trust significantly influences perceived benefits and perceived risks, while trust, perceived benefits, and perceived risks significantly influence the intention to consult. The intention to consult positively influences the intention to visit. Considering the moderating effects of payment types, the influence of perceived risks on the intention to consult is larger for the free group than for the paid group. The findings are useful to better understand patients’ decisions to use eHealth

STUDY ON THE NON-LINEAR VIBRATION IN THE HYDRAULIC SCREW DOWN VERTICAL SYSTEM FOR ROLLING MILL

For vertical vibration systems tend to ignore the influence of hydraulic screw down system in the rolling mill,two degrees of freedom hydraulic screw down vertical vibration system model was established based on viscous damping between the hydraulic cylinder and the frame,nonlinear stiffness between the rolling interface. By means of a multiple scales method,the existence and stability of periodic solutions in a first order approximation close to the main parametric resonance were investigated,and the frequency-response equation was provided. The impacts of nonlinear stiffness and viscous damping on the rolling mill vibration were analyzed,and the impacts of excitation frequency on non-linear vertical vibration were analyzed by the phase plane method,the Poincare mapping method and the maximum Lyapunov exponent. Analysis’ s results provide a reference for engineering to solve the vibration problem of hydraulic screw down system

Analysis of clinical and CT characteristics of patients with Klebsiella pneumoniae liver abscesses: an insight into risk factors of metastatic infection

Purpose: To compare the clinical and CT characteristics of patients with Klebsiella pneumoniae liver abscess (KPLA), with or without metastatic infection. Materials and Methods: Clinical information (age, sex, clinical symptoms, underlying disease, hematological parameters, abscess-related mortality) and CT characteristics of abscesses were analyzed to investigate associations with metastatic infection. Metastatic infections were divided into septic pulmonary embolism (SPE) and extra-pulmonary metastatic infection (EMI). Results: We identified 66 consecutive patients with KPLA. Metastatic infection occurred in 22/66 patients (33.3%); 8/66 (12.1%) patients had SPE, 6/66 (9.09%) patients had EMI; and 8/66 (12.1%) patients had both SPE and EMI. Patients with SPE were younger than patients without SPE (47.7 ± 13.7 y vs.55.6 ± 12.0 y; p = 0.03). Unilocular abscess was significantly more common in patients with SPE than the non-SPE group (43.75% vs 18.0%, p = 0.036). The mean maximal diameter of EMI was 56.5 ± 21.3 mm and was significantly smaller than that of the non-EMI which was 79.9 ± 31.4 (p = 0.011). SPE was significantly associated with development of EMI (50% vs17.3%, p = 0.011). Conclusion: Unilocular liver abscess is associated with SPE, and SPE is strongly associated with EMI among patients with KPLA. A maximal diameter of KPLA<55 mm can be used as a predictor of EMI

Metabolic Characterization of Peripheral Host Responses to Drainage-Resistant Klebsiella pneumoniae Liver Abscesses by Serum 1H-NMR Spectroscopy

Purpose: To explore the metabolic characterization of host responses to drainage-resistant Klebsiella pneumoniae liver abscesses (DRKPLAs) with serum 1H-nuclear magnetic resonance (NMR) spectroscopy.Materials and Methods: The hospital records of all patients with a diagnosis of a liver abscess between June 2015 and December 2016 were retrieved from an electronic hospital database. Eighty-six patients with Klebsiella pneumoniae (K. pneumoniae) liver abscesses who underwent percutaneous drainage were identified. Twenty patients with confirmed DRKPLAs were studied. Moreover, we identified 20 consecutive patients with drainage-sensitive Klebsiella pneumoniae liver abscesses (DSKPLAs) as controls. Serum samples from the two groups were analyzed with 1H NMR spectroscopy. Partial least squares discriminant analysis (PLS-DA) was used to perform 1H NMR metabolic profiling. Metabolites were identified using the Human Metabolome Database, and pathway analysis was performed with MetaboAnalyst 3.0.Results: The PLS-DA test was able to discriminate between the two groups. Five key metabolites that contributed to their discrimination were identified. Glucose, lactate, and 3-hydroxybutyrate were found to be upregulated in DRKPLAs, whereas glutamine and alanine were downregulated compared with the DSKPLAs. Pathway analysis indicated that amino acid metabolisms were significantly different between the DRKPLAs and the DSKPLAs. The D-glutamine and D-glutamate metabolisms exhibited the greatest influences.Conclusions: The five key metabolites identified in our study may be potential targets for guiding novel therapeutics of DRKPLAs and are worthy of additional investigation

Laboratory experimental study of the evaporation and mechanical behaviour of deposited tailings

Surface deposition has been widely used in the mining industry to manage mill tailings. Tailings are generally discharged in the form of a slurry into tailings ponds. The slurried tailings are deposited in layers that undergo complex processes, e.g. evaporation, desiccation and consolidation. The evaporation of the deposited tailings controls their geotechnical engineering behaviour, which is necessary to characterise the physical properties. In this study, a constant temperature device was employed in evaporation tests to investigate two classes of deposited tailings, and the effects of the initial concentration, particle size, exposure area and deposited layer thickness on the evaporation processes were analysed. The test results showed four stages in the evaporation processes of deposited coarse and fine tailings. Dewatering of the deposited tailings occurred during the first two stages, which were keys to improving the desiccation efficiency of the tailings in the pond. The exposure area and deposited layer thickness also had a considerable influence on evaporation. The evaporation rate increased with the exposure area and layer thickness. Direct shear tests were performed to measure the shear strength of intact tailings during evaporation and used to determine the variation law of the mechanical properties of the test tailings. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature