Search

The availability of accurate toponyms in user tweets is crucial for geolocating Twitter users.However, existing methods for locating Twitter users often suffer from limited quantity and reliability of acquired toponyms, thus impacting the accuracy of user geolocation.To address this issue, a twitter user geolocation method based on single-point toponym matching and local toponym filtering was proposed.A toponym type discriminating algorithm based on the aggregation degree of locations of the toponym was designed.In the proposed algorithm, a single-point toponym database was generated to provide more reliable toponyms extracted from tweets.Then, according to a proposed local place name filtering algorithm based on the aggregation degree of user location, the aggregation degree of user location centered on the longitude and latitude of toponyms and the average longitude and latitude of users were calculated.This process helped in extracting local toponyms with a high aggregation degree, which enhances the reliability of toponyms used in geolocation.Finally, a user-toponym heterogeneous graph was constructed based on user social relationships and user mentions of toponyms, and users were located by graph representation learning and neural networks.A large number of user geolocation experiments were conducted based on two commonly used public datasets in this field, namely GEOTEXT and TW-US.Comparisons with nine existing typical methods for Twitter user geolocation, including HGNN, ReLP, and GCN, demonstrate that our proposed method achieves significantly higher geolocation accuracy.On the GEOTEXT dataset, the average error is reduced by 7.3～342.8 km, the median error is reduced by 2.4～354.4 km, and the accuracy of large area-level geolocation is improved by 1.3%～26.3%.On the TW-US dataset, the average error is reduced by 8.6～246.6 km, the median error is reduced by 5.7～149.7 km, and the accuracy of large area-level geolocation is improved by 1.5%～20.5%.

Objective To evaluate the morphology of the upper airway of children with obstructive sleep apnea-hypopnea syndrome (OSAHS) using cone-beam computed tomography (CBCT) combined with polysomnography (PSG) and provide references for clinical practice. Methods CBCT data of 45 OSAHS children and 45 normal children and PSG data of the OSAHS group were retrospectively collected. Three-dimensional reconstructions were performed using NNT 9.0 software. The total upper airway volume, nasopharyngeal volume, palatopharyngeal volume, glossopharyngeal volume, laryngopharyngeal volume, minimum cross-sectional area, anterior-posterior diameter of the minimum cross-section, and lateral diameter of the minimum cross-section were measured and recorded. According to PSG monitoring results, patients with an obstructive apnea hypopnea index (OAHI) and lowest oxygen saturation (LSaO2) were assessed. Body mass index (BMI) was recorded. The correlation between airway volume parameters, BMI and PSG test results was analyzed. Results The total upper airway volume, nasopharyngeal volume, palatopharyngeal volume, glossopharyngeal volume, laryngopharyngeal volume, minimum cross-sectional area, anterior-posterior diameter of the minimum cross-section, and lateral diameter of the minimum cross-section of the OSAHS group were significantly reduced compared with those of the control group (P0.05). No significant correlation was noted between BMI and PSG in the OSAHS group (P>0.05). Conclusion The morphology of the upper airway of children with OSAHS was significantly smaller than that of normal children. CBCT three-dimensional technology for analyzing the upper airway has a certain value in evaluating the morphology and degree of obstruction of the upper airway in children with OSAHS.

The rotating blade is a key component of an aero-engine, and its vibration characteristics have an important impact on the performance of the engine and are vital for condition monitoring. This paper reviews the research progress of blade dynamics, including three main aspects: modeling of blades, solution methods, and vibration characteristics. Firstly, three popular structural dynamics models for blades are reviewed, namely lumped-mass model, finite element model, and semi-analytical model. Then, the solution methods for the blade dynamics are comprehensively described. The advantages and limitations of these methods are summarized. In the third part, this review summarizes the properties of the modal and vibration responses of aero-engine blades and discusses the typical forms and mechanisms of blade vibration. Finally, the deficiencies and limitations in the current research on blade modeling and vibration analysis are summarized, and the directions for future efforts are pointed out. The purpose of this review is to provide meaningful insights to researchers and engineers in the field of aero-engine blade modeling and dynamic characteristics analysis. [ABSTRACT FROM AUTHOR]

In order to study the seismic performance of cold-formed, thin-walled C-shaped steel composite wall, a set of cold-formed thin-walled C-shaped steel skeleton structure and a set of composite wall covered with fireproof straw boards on both sides were tested with a low cyclic alternative load. The seismic performance indexes, such as bearing capacity characteristic value, lateral stiffness, ductility coefficient, energy dissipation coefficient and stiffness degradation, were analysed by obtaining the backbone curves of each group of specimens. The effects of fireproof straw boards on the seismic performance of the composite wall were compared, and a mechanical analysis model of the cold-formed thin-walled C-shaped steel composite wall was established by using ANSYS/structural finite element software. The results show that the damage patterns, backbone curves and capacity characteristic values of the finite element model are in general agreement with the tests. The bearing capacity and lateral stiffness of the light steel skeleton structure without boards is very low, while the bearing capacity of the composite wall with straw boards on both sides is significantly increased. The lateral stiffness increased by 10.76%, the ductility coefficient increased by 27.34% and the energy dissipation coefficient decreased by 45.8%. [ABSTRACT FROM AUTHOR]

In this paper, a Multi-Index Nonlinear Robust Adaptive Control (MINRAC) method was proposed for ultra-complex multi-input multi-output power systems with uncertain parameter factors and external disturbances. The controller designed by this method has excellent static and dynamic characteristics. Under the condition of the uncertainty of system parameters and external disturbance at the same time, the MINRAC method can ensure that the multiple indexes concerned by ultra-complex power systems can be controlled at their expected values. The simulation results showed that the control mechanism of MINRAC method was consistent in both single-machine infinite bus system and multi-machine interconnected coupling system. The output function chooses power angle, angular frequency and terminal voltage as constraints. When the system has parameter uncertainty and external interference, the uncertain parameter values are adjusted by adaptive control to force these indicators to tend to the given expected value. For three-phase short circuit, which is the most serious fault in power system, the use of multi index nonlinear robust controller can ensure that the system is stable in a wide range and has better dynamic performance. [ABSTRACT FROM AUTHOR]

Turmeric (Curcuma longa L.) is a perennial tuberous plant from the genus Curcuma (Zingiberaceae) and has been widely used in foods for thousands of years. The present study examined the ethanol extract of turmeric for its chemical composition, antimicrobial activity, and free radical scavenging properties. UHPLC-MS/MS analysis tentatively identified eight compounds in the turmeric extract. Potential antimicrobial effects of 0.1, 1.0, and 10 mg turmeric equivalents (TE)/mL were evaluated in vitro against a variety of Gram-negative bacteria (i.e., Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp.) and Gram-positive bacteria (i.e., Enterococcus faecalis, Listeria innocua, and Staphylococcus aureus). Concentrations of 0.1 and 1.0 mg TE/mL inhibited the growth of S. aureus and significantly suppressed that of Pseudomonas sp., E. faecalis, and L. innocua. The growth of all strains, including E. coli, was inhibited by 10 mg TE/mL. Moreover, free radical scavenging capacities were determined using HO●, ABTS●+, and DPPH● (HOSC, ABTS, and RDSC, respectively) radicals. The turmeric ethanol extract had a TPC value of 27.12 mg GAE/g, together with HOSC, RDSC, and ABTS values of 1524.59, 56.38, and 1.70 μmol TE/g, respectively. Our results suggest that turmeric extract has potential applications for use in functional foods to reduce microbial burdens and oxidative stress-related health problems. [ABSTRACT FROM AUTHOR]