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QoE oriented intelligent online learning evaluation technology in B5G scenario

Digital Communications and Networks 2024年第1期10卷 7-15页

作者： Mingzi Chen xin Wei Peizhong Xie zhe Zhang School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing210003China Institute of Higher Education Nanjing University of Posts and TelecommunicationsNanjing210003China

Students'demand for online learning has exploded during the post-COvID-19 pandemic ***,due to their poor learning experience,students'dropout rate and learning performance of online learning are not always *** technical advantages of Beyond Fifth Generation(B5G)can guarantee a good multimedia Quality of Experience(QoE).As a special case of multimedia services,online learning takes into account both the usability of the service and the cognitive development of the *** that affect the Quality of Online Learning Experience(OL-QoE)become more *** get over this dilemma,we propose a systematic scheme by integrating big data,Machine Learning(ML)technologies,and educational psychology ***,we first formulate a general definition of OL-QoE by data analysis and experimental *** formula considers both the subjective and objective factors(i.e.,video watching ratio and test scores)that most affect ***,we induce an extended layer to the classic Broad Learning System(BLS)to construct an Extended Broad Learning System(EBLS)for the students'OL-QoE *** the extended layer can increase the width of the BLS model and reduce the redundant nodes of BLS,the proposed EBLS can achieve a trade-off between the prediction accuracy and computation ***,we provide a series of early intervention suggestions for different types of students according to their predicted OL-QoE *** timely interventions,their OL-QoE and learning performance can be *** results verify the effectiveness oftheproposed scheme.

关键词： B5G Online learning Quality of experience

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Experimental and numerical study on protective effect of RC blast wall against air shock wave

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Defence Technology（防务技术） 2024年第1期31卷 567-579页

作者： xin-zhe Nian Quan-min Xie xin-li Kong Ying-kang Yao Kui Huang State Key Laboratory of Precision Blasting Jianghan UniversityWuhan430056China Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan430056China Hubei(Wuhan)Institute of Explosion and Blasting Technology Jianghan UniversityWuhan430056China College of Defense Engineering Army Engineering University of PLANanjing210007China Institute of Defense Engineering AMSPLALuoyang471023China

Prototype experiments were carried out on the explosion-proof performance of the RC blast *** mass of TNT detonated in the experiments is 5 kg and 20 kg *** shock wave overpressure was tested in different *** above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP *** results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP *** dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was *** to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are *** above results can provide a reference for the design and construction of the reinforced concrete blast wall.

关键词： Blast wall Shock wave Diffraction Overpressure Protection

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Magnetic resonance imaging-based lymph node radiomics for predicting the metastasis of evaluable lymph nodes in rectal cancer

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1849-1860页

作者： Yong-Xia Ye Liu Yang zheng Kang mei-Qin Wang Xiao-Dong Xie Ke-xin Lou Jun Bao mei Du zhe-Xuan Li Department of Radiology The Affiliated Cancer Hospital of Nanjing Medical University&Jiangsu Cancer Hospital&Jiangsu Institute of Cancer ResearchNanjing 210011Jiangsu ProvinceChina Department of Colorectal Surgery Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research and The Affiliated Cancer Hospital of Nanjing Medical UniversityNanjing 210000Jiangsu ProvinceChina1 Department of Pathology The Affiliated Cancer Hospital of Nanjing Medical University&Jiangsu Cancer Hospital&Jiangsu Institute of Cancer ResearchNanjing 210011Jiangsu ProvinceChina Colorectal Center The Affiliated Cancer Hospital of Nanjing Medical University&Jiangsu Cancer Hospital&Jiangsu Institute of Cancer ResearchNanjing 210011Jiangsu ProvinceChina

BACKGROUND Lymph node(LN)staging in rectal cancer(RC)affects treatment decisions and patient *** radiologists,the traditional preoperative assessment of LN metastasis(LNM)using magnetic resonance imaging(MRI)poses a *** To explore the value of a nomogram model that combines Conventional MRI and radiomics features from the LNs of RC in assessing the preoperative metastasis of evaluable *** In this retrospective study,270 LNs(158 nonmetastatic,112 metastatic)were randomly split into training(n=189)and validation sets(n=81).LNs were classified based on pathology-MRI *** MRI features[size,shape,margin,T2-weighted imaging(T2WI)appearance,and CE-T1-weighted imaging(T1WI)enhancement]were *** radiomics models used 3D features from T1WI and T2WI ***,a nomogram model combining conventional MRI and radiomics features was *** model used univariate analysis and multivariable logistic *** employed the receiver operating characteristic curve,with DeLong test for comparing diagnostic *** performance was assessed using calibration and decision curve *** The nomogram model outperformed conventional MRI and single radiomics models in evaluating *** the training set,the nomogram model achieved an area under the curve(AUC)of 0.92,which was significantly higher than the AUCs of 0.82(P<0.001)and 0.89(P<0.001)of the conventional MRI and radiomics models,*** the validation set,the nomogram model achieved an AUC of 0.91,significantly surpassing 0.80(P<0.001)and 0.86(P<0.001),*** The nomogram model showed the best performance in predicting metastasis of evaluable LNs.

关键词： Radiomics Lymph node metastasis Rectal cancer Magnetic resonance imaging

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Biderivations of Hom-Lie Algebras and Superalgebras

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2337-2358页

作者： La mei YUAN Jia xin LI School of Mathematics Harbin Institute of Technology

On Hom-Lie algebras and superalgebras, we introduce the notions of biderivations and linear commuting maps, and compute them for some typical Hom-Lie algebras and superalgebras,including the q-deformed W(2, 2) algebra... 详细信息

关键词： 17A30 17A60 17B05 17B60 17B70 biderivations Hom-Lie algebras linear commuting maps q-deformed W(2 2) algebra q-deformed Witt algebra q-deformed Witt superalgebra

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Effect of End Shape on Flow and Heat Transfer Characteristics of Two Parallel Plates

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Journal of Thermal Science 2024年第3期33卷 815-832页

作者： ZHANG Guang HONG Tianxiao WANG Dongrui xin Jialin TAO Junyu LIN zhe Key Laboratory of Fluid Transmission Technology of zhejiang Province Zhejiang Sci-Tech UniversityHangzhou310018China

Flow around a pair of flat plates is a basic hydrodynamics *** this paper,the flow and heat transfer characteristics of two parallel plates with different edge shapes are numerically *** different inclined angles,the influence of chamfered and rounded structures with different sizes at the end-edge on unsteady flow and heat transfer characteristics of two parallel plates are *** is found that the instability and unsteadiness of flow decrease with the increase of end-edge size,and the non-uniformity of wake velocity of both rounded and chamfered plates decreases *** non-uniformity of wake temperature increases firstly and then decreases at a small inclined angle,and the amplitude becomes the largest when S_(rou)(S_(cha))=3,while it basically keeps monotonically increasing at a large inclined ***,the global heat transfer performance of the flat plate is obviously affected by the end-edge modification,especially the chamfered *** the increase of chamfered size,the global Nusselt number basically shows the decreasing *** study provides a theoretical basis for the application of plate-shape structure in engineering fields.

关键词： two parallel plates end shape flow characteristic heat transfer numerical simulation

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Experimental study on the size effect on the equation of state of concretes under shock loading

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Defence Technology（防务技术） 2024年第3期33卷 160-167页

作者： mei Li Jian Cui Yanchao Shi Baijian Tang xin Chen Key Laboratory of Coast Civil Structural Safety of the Ministry of Education Tianjin UniversityTianjin 300072China School of Civil Engineering Suzhou University of Science and Technology1701 Binhe RoadSuzhou 215011JiangsuChina School of Civil Engineering Tianjin UniversityTianjin 300072China

Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which depicts the shear properties of *** experiments on the EoS of concrete is always challenging due to the technical difficulties and equipment limitations,especially for the specimen size effect on the *** some researchers investigate the shock properties of concretes by fly-plate impact tests,the specimens used in their tests are usually in one *** this paper,the fly-plate impact tests on concrete specimens with different sizes are performed to investigate the size effect on the shock properties of concrete *** mechanical background of the size effect on the shock properties are revealed,which is related to the lateral rarefaction effect and the deviatoric stress produced in the *** to the tests results,the modified EoS considering the size effect on the shock properties of concrete are proposed,which the bulk modulus of concrete is unpredicted by up to 20% if size effects are not accounted for.

关键词： Concrete Equation of state Size effect Shock wave Fly-plate impact test

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Machine learning-driven optimization of plasma-catalytic dry reforming of methane

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Journal of Energy Chemistry 2024年第9期96卷 153-163页

作者： Yuxiang Cai Danhua mei Yanzhen Chen Annemie Bogaerts xin Tu Department of Electrical Engineering and Electronics University of LiverpoolLiverpool L693GJUK Research Group PLASMANT Department of ChemistryUniversity of AntwerpUniversiteitsplein 1BE-2610 Wilrijk-AntwerpBelgium College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816JiangsuChina

This study investigates the dry reformation of methane(DRM)over Ni/Al_(2)O_(3)catalysts in a dielectric barrier discharge(DBD)non-thermal plasma reactor.A novel hybrid machine learning(ML)model is developed to optimize the plasma-catalytic DRM reaction with limited experimental *** address the non-linear and complex nature of the plasma-catalytic DRM process,the hybrid ML model integrates three well-established algorithms:regression trees,support vector regression,and artificial neural networks.A genetic algorithm(GA)is then used to optimize the hyperparameters of each algorithm within the hybrid ML *** ML model achieved excellent agreement with the experimental data,demonstrating its efficacy in accurately predicting and optimizing the DRM *** model was subsequently used to investigate the impact of various operating parameters on the plasma-catalytic DRM *** found that the optimal discharge power(20 W),CO_(2)/CH_(4)molar ratio(1.5),and Ni loading(7.8 wt%)resulted in the maximum energy yield at a total flow rate of∼51 mL/***,we investigated the relative significance of each operating parameter on the performance of the plasma-catalytic DRM *** results show that the total flow rate had the greatest influence on the conversion,with a significance exceeding 35%for each output,while the Ni loading had the least impact on the overall reaction *** hybrid model demonstrates a remarkable ability to extract valuable insights from limited datasets,enabling the development and optimization of more efficient and selective plasma-catalytic chemical processes.

关键词： Plasma catalysis Machine learning Process optimization Dry reforming of methane Syngas production

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Prevalence and Related Factors of Falls among the Elderly in an Urban Community of Beijing

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Biomedical and Environmental Sciences 2009年第3期22卷 179-187页

作者： PU-LIN YU ZHAO-HUI QIN JING SHI JUAN ZHANG mei-zhe xin zheNG-LAI WU zheN-QIU SUN School of Public Health Central South University Changsha 410078 Hunan China Department of Public Health Xuzhou Medical College Xuzhou 221002 Jiangsu China Institute of Geriatrics Beijing Hospital Ministry of Health Beijing 100730 China Department of Applied Health Science Indiana University 47408 Bloomington Indiana USA Office of Program Management Chinese Preventive Medicine Association Beijing 100009 China Department of Epidemiology Peking Union Medical College Beijing 100005 China

Objective To understand the prevalence, consequences and risk factors of falls among urban community-dwelling elderly in Beijing. Methods A cross-sectional study was conducted in Longtan Community, Beijing. A total of 1512 individuals aged 60 years or over were selected by stratified cluster sampling. Data regarding the frequency of falls in the previous year, as well as circumstances, consequence and related factors of falls were collected from the elderly through face-to-face interviews with questionnaires in their home. Results The prevalence of falls was 18.0% on the average among 1512 participants, higher in women （20.1%） than in men （14.9%）（P=0.006）, and increased with age （Х^2 for trend=10.37, P=0.001）. The total rate of falls-induced injuries among the fallers was 37.7%. Falls usually resulted in soft-tissues bruises （58.7%）, fear of repeated episodes of falls （58.8%）, loss of independence and confidence in movement （35.7%） and even in hip fracture. In addition to the burden of medical care, falls also generated a big economic burden. Occurrence of falls was significantly associated with both intrinsic and extrinsic factors. The related factors of falls in the elderly included age≥60-70 years, femininity, less physical activities, fear of future falls, living alone, severely impaired vision, health problem-impacted activities of daily living, chronic diseases （diabetes, hypertension, postural hypotension, stroke sequela, cataract, arthritis, dementia and depression）, medications （psychoactive, anti-diabetic）, gait imbalance, high bed and faintly-lighted stairway. Conclusion The prevalence of falls among urban community-dwelling elderly in Beijing is closely associated with significant associated with intrinsic and extrinsic factors. Efforts to prevent falls in the elderly should be made at community level.

关键词： Falls Prevalence Old people Prevention

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The influences of perforating phase and bedding planes on the fracture deflection in laminated shale

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Petroleum Science 2024年第2期21卷 1221-1230页

作者： Ming-zhe Gu Mao Sheng Xiao-Ying Zhuang xin-Yi Li Gen-Sheng Li National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China College of Petroleum Engineering China University of PetroleumBeijing102249China College of Civil Engineering Tongji UniversityShanghai200092China

The perforating phase leads to complex and diverse hydraulic fracture propagation behaviors in laminated shale formations. In this paper, a 2D high-speed imaging scheme which can capture the interaction between perforating phase and natural shale bedding planes was proposed. The phase field method was used to simulate the same conditions as in the experiment for verification and hydraulic fracture propagation mechanism under the competition of perforating phase and bedding planes was *** results indicate that the bedding planes appear to be no influence on fracture propagation while the perforating phase is perpendicular to the bedding planes, and the fracture propagates along the perforating phase without deflection. When the perforating phase algins with the bedding planes, the fracture initiation pressure reserves the lowest value, and no deflection occurs during fracture propagation. When the perforating phase is the angle 45°, 60°and 75°of bedding planes, the bedding planes begin to play a key role on the fracture deflection. The maximum deflection degree is reached at the perforating phase of75°. Numerical simulation provides evidence that the existence of shale bedding planes is not exactly equivalent to anisotropy for fracture propagation and the difference of mechanical properties between different shale layers is the fundamental reason for fracture deflection. The findings help to understand the intrinsic characteristics of shale and provide a theoretical basis for the optimization design of field perforation parameters.

关键词： Shale Propagation Perforating Bedding Structure

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Highly dispersed MgInCe-mixed metal oxides catalyzed direct carbonylation of glycerol and CO_(2)into glycerol carbonate

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Chinese Journal of Chemical Engineering 2024年第8期72卷 153-163页

作者： Xufang Chen xin Shu Yanru Zhu Jian Zhang Zhigang Chai Hongyan Song zhe An Jing He State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Quzhou Institute for Innovation in Resource Chemical Engineering Quzhou 324000China

Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so *** direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol *** investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.

关键词： Catalytic reaction engineering Glycerol carbonate Direct carbonylation from glycerol Carbon dioxide Mixed metal oxides Synergistic catalysis

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