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Querying Big Data: Bridging Theory and Practice

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Journal of Computer Science & Technology 2014年第5期29卷 849-869页

作者：樊文飞怀进鹏 School of Informatics University of EdinburghEdinburgh EH8 9AB U.K. International Research Center on Big Data Beihang University School of Computer Science and Engineering Beihang University

Big data introduces challenges to query answering, from theory to practice. A number of questions arise. What queries are ＂tractable＂ on big data？ How can we make big data ＂small＂ so that it is feasible to find exact query answers？When exact answers are beyond reach in practice, what approximation theory can help us strike a balance between the quality of approximate query answers and the costs of computing such answers？ To get sensible query answers in big data,what else do we necessarily do in addition to coping with the size of the data？ This position paper aims to provide an overview of recent advances in the study of querying big data. We propose approaches to tackling these challenging issues,and identify open problems for future research.

关键词： big data query answering tractability approximation data quality

A nonlocal dispersal and time delayed HIV infection model with general incidences

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Applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 448-457页

作者： WU peng ZHANG Yu-huai WANG Ling School of Sciences Hangzhou Dianzi UniversityHangzhou 310018China School of Humanities and Management Zhejiang Chinese Medical UniversityHangzhou 311402China Public Foundational Courses Department Nanjing Vocational University of Industry TechnologyNanjing 210023China

Biologically,because of the impact of reproduction period and nonlocal dispersal of HIV-infected cells,time delay and spatial heterogeneity should be *** this paper,we establish an HIV infection model with nonlocal dispersal and infection ***,applying the theory of Fourier transformation and von Foerster rule,we transform the model to an integrodifferential equation with nonlocal time delay and *** well-posedness,positivity,and boundedness of the solution for the model are studied.

关键词： HIV model nonlocal dispersal time delay general incidences

Simple preparation of C(CS)/g-C_(3)N_(4)/Co carbon aerogel and its catalytic performance for ammonium perchlorate

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Defence Technology（防务技术） 2024年第3期33卷 186-196页

作者： Yujie Yan Bo jin Rufang peng State Key Laboratory of Environment-friendly Energy Materials School of Materials Science and EngineeringSouthwest University of Science and TechnologyMianyang621010China

Biomass chitosan(CS)was used as a template,graphitic phase carbon nitride(g-C_(3)N_(4))with high nitrogen content and certain catalytic activity was used as a dopant,and nano-transition metal cobalt(Co)was used as a catalytic center *** carbon aerogel(C(CS)/g-C_(3)N_(4)/Co)with a three-dimensional network-like structure was prepared by assembling the three materials through experimental operations such as freeze-drying and high-temperature *** was demonstrated by scanning and transmission characterization that the CS in the carbon aerogel could provide more active sites for the cobalt nanoparticles,and the doping of graphite-phase carbon nitride as a template dispersed the cobalt nanoparticles and changed the conductivity of the *** investigate the catalytic effect of carbon aerogel on ammonium perchlorate(AP),it was investigated by differential thermal analyzer and TG thermal *** carbon aerogel was very effective in catalyzing AP,and the 10 wt% content of the catalyst reduced the AP pyrolysis peak from 703.9 to 595.5 *** to further investigate the synergistic effect of the three materials,further carbon aerogels such as C(CS)/Co,g-C_(3)N_(4)/Co were prepared and applied to catalyze AP,and the same ratio reduced the AP pyrolysis peak by 98.1℃ and 97.7℃.This result indicates a synergistic effect of the assembly of the three materials.

关键词： g-C_(3)N_(4) Chitosan Co Ammonium perchlorate Pyrolysis kinetics

Guaranteed Cost Attitude Tracking Control for Uncertain Quadrotor Unmanned Aerial Vehicle Under Safety Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1447-1457页

作者： Qian Ma peng jin Frank L.Lewis School of Automation Nanjing University of Science and TechnologyNanjing 210094China UTA Research Institute University of Texas at ArlingtonFort WorthTexas 76118 USA IEEE

In this paper,guaranteed cost attitude tracking con-trol for uncertain quadrotor unmanned aerial vehicle(QUAV)under safety constraints is ***,an augmented system is constructed by the tracking error system and reference *** transformation aims to convert the tracking control prob-lem into a stabilization control ***,control barrier function and disturbance attenuation function are designed to characterize the violations of safety constraints and tolerance of uncertain disturbances,and they are incorporated into the reward function as penalty *** on the modified reward function,the problem is simplified as the optimal regulation problem of the nominal augmented system,and a new Hamilton-Jacobi-Bellman equation is ***,critic-only rein-forcement learning algorithm with a concurrent learning tech-nique is employed to solve the Hamilton-Jacobi-Bellman equa-tion and obtain the optimal *** proposed algorithm can not only ensure the reward function within an upper bound in the presence of uncertain disturbances,but also enforce safety *** performance of the algorithm is evaluated by the numerical simulation.

关键词： Attitude tracking control quadrotor unmanned aerial vehicle(QUAV) reinforcement learning safety constraints uncertain disturbances.

Heat exposure and hospitalizations for chronic kidney disease in China: a nationwide time series study in 261 major Chinese cities

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Military Medical Research 2024年第4期11卷 469-478页

作者： Fu-Lin Wang Wan-Zhou Wang Fei-Fei Zhang Su-Yuan peng huai-Yu Wang Rui Chen jin-Wei Wang peng-Fei Li Yang Wang Ming-Hui Zhao Chao Yang Lu-Xia Zhang Institute of Medical Technology Peking University Health Science CenterBeijing 100191China National Institute of Health Data Science at Peking University Beijing 100191China Department of Occupational and Environmental Health Sciences School of Public HealthPeking UniversityBeijing 100191China Renal Division Department of MedicinePeking University First HospitalPeking University Institute of NephrologyBeijing 100034China Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases Chinese Academy of Medical SciencesBeijing 100034China Advanced Institute of Information Technology Peking UniversityHangzhou 311215China National Climate Center China Meteorological AdministrationBeijing 100081China Peking-Tsinghua Center for Life Sciences Beijing 100034China

Background:Climate change profoundly shapes the population health at the global ***,there was still insufficient and inconsistent evidence for the association between heat exposure and chronic kidney disease(CKD).Methods:In the present study,we studied the association of heat exposure with hospitalizations for cause-specific CKD using a national inpatient database in China during the study period of hot season from 2015 to *** time-series regression models and random-effects Meta-analysis were developed to estimate the city-specific and national averaged associations at a 7 lag-day span,***:A total of 768,129 hospitalizations for CKD was recorded during the study *** results showed that higher temperature was associated with elevated risk of hospitalizations for CKD,especially in sub-tropical *** a 1℃ increase in daily mean temperature,the cumulative relative risks(RR)over lag 0-7 d were 1.008[95% confidence interval(CI)1.003-1.012]for *** attributable fraction of CKD hospitalizations due to high temperatures was 5.50%.Stronger associations were observed among younger patients and those with obstructive *** study also found that exposure to heatwaves was associated with added risk of hospitalizations for CKD compared to non-heatwave days(RR=1.116,95%CI 1.069-1.166)above the effect of daily mean ***:Short-term heat exposure may increase the risk of hospitalization for *** findings provide insights into the health effects of climate change and suggest the necessity of guided protection strategies against the adverse effects of high temperatures.

关键词： Chronic kidney disease Hospitalization Climate change Temperature Time-series study

Highly efficient capture of thorium ion by citric acid-modified chitosan gels from aqueous solution

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Chinese Chemical Letters 2024年第5期35卷 361-365页

作者： Linshan peng Qihang peng Tianxiang jin Zhirong Liu Yong Qian State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices East China University of TechnologyNanchang 330013China

A novel citric acid-modified chitosan gel(CSCA)was synthesized through a simple one-step process and was used to extract thorium ions from *** CSCA samples with varying chemical compositions were analyzed using SEM with mapping EDS,FT-IR,and static water contact angle measurements,and their adsorption behaviors were studied in *** results showed that the adsorption performance of CSCA improves with the increase of CA content in the *** possesses an impressive capacity for thorium adsorption of 279.8 mg/***,it showed an ultra-fast adsorption rate and reached equilibrium within 30 *** terms of recyclability,the CSCA still retained more than 86%of its initial adsorption capacity after 6 cycles of *** functional theory(DFT)analysis reveals that the good selectivity of this material towards thorium ions should be attributed to the high density of adsorption sites and strong interaction between carboxyl groups and thorium *** work could be beneficial in the design and synthesis of new polymer materials for extracting thorium.

关键词： Thorium Adsorption Citric acid Chitosan DFT calculation

Revolutionizing plasmonic platform via magnetic field-assisted confined ultrafast laser deposition of high-density,uniform,and ultrafine nanoparticle arrays

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International Journal of Extreme Manufacturing 2024年第3期6卷 428-438页

作者： jin Xu Lingfeng Wang Peilin Yang Haoqing Jiang huai Zheng Licong An Xingtao Liu Gary J Cheng School of Industrial Engineering Purdue UniversityWest LafayetteIN 47906United States of America Institute of Technological Sciences Wuhan UniversityWuhanHubei 430072People’s Republic of China

The remarkable capabilities of 2D plasmonic surfaces in controlling optical waves havegarnered significant ***,the challenge of large-scale manufacturing of uniform,well-aligned,and tunable plasmonic surfaces has hindered their *** address this,we present a groundbreaking tunable plasmonic platform design achieved throughmagnetic field(MF)assisted ultrafast laser direct deposition in *** precise control of metal nanoparticles(NPs),with cobalt(Co)serving as the model material,employing an MF,and fine-tuning ultrafast laser parameters,we have effectively converted coarse and non-uniform NPs into densely packed,uniform,and ultrafine NPs(~3 nm).This revolutionary advancement results in the creation of customizable plasmonic‘hot spots,’which play a pivotal role insurface-enhanced Raman spectroscopy(SERS)*** profound impact of this designable plasmonic platform lies in its close association with plasmonic resonance and *** the plasmonic nanostructures resonate with incident light,they generate intense local electromagnetic fields,thus vastly increasing the Raman scattering *** enhancement leads to an outstanding 2–18 fold boost in SERS performance and unparalleled sensing sensitivity down to 10^(-10)***,the plasmonic platform also demonstratesrobustness,retaining its sensing capability even after undergoing 50 cycles of rinsing andre-loading of ***,this work adheres to green manufacturing standards,making it an efficient and environmentally friendly method for customizing plasmonic‘hot spots’inSERS *** study not only achieves the formation of high-density,uniform,and ultrafine NP arrays on a tunable plasmonic platform but also showcases the profound relation betweenplasmonic resonance and energy *** outstanding results observed in SERS sensors further emphasize the immense potential of this technology for energy-relatedapplications,including photocatalysis,ph

关键词： magnetic field manipulation laser deposition metasurface SERS

Multi-Scale Binocular Stereo Matching Based on Semantic Association

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Chinese Journal of Electronics 2024年第4期33卷 1010-1022页

作者： jin ZHENG Botao JIANG Wei peng Qiaohui ZHANG State Key Laboratory of Virtual Reality Techonology and Systems Beihang University School of Computer Science and Engineering Beihang University

Aiming at the low accuracy of existing binocular stereo matching and depth estimation methods, this paper proposes a multi-scale binocular stereo matching network based on semantic association. A semantic association module is designed to construct the contextual semantic association relationship among the pixels through semantic category and attention mechanism. The disparity of those regions where the disparity is easily estimated can be used to assist the disparity estimation of relatively difficult regions, so as to improve the accuracy of disparity estimation of the whole image. Simultaneously, a multi-scale cost volume computation module is proposed. Unlike the existing methods, which use a single cost volume, the proposed multi-scale cost volume computation module designs multiple cost volumes for features of different scales. The semantic association feature and multi-scale cost volume are aggregated, which fuses the high-level semantic information and the low-level local detailed information to enhance the feature representation for accurate stereo matching. We demonstrate the effectiveness of the proposed solutions on the KITTI2015 binocular stereo matching dataset, and our model achieves comparable or higher matching performance, compared to other seven classic binocular stereo matching algorithms.

关键词： Costs Accuracy Attention mechanisms Fuses Computational modeling Semantics Estimation

Advancements in machine learning for material design and process optimization in the field of additive manufacturing

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China Foundry 2024年第2期21卷 101-115页

作者： Hao-ran Zhou Hao Yang huai-qian Li Ying-chun Ma Sen Yu Jian shi jing-chang Cheng peng Gao Bo Yu Zhi-quan Miao Yan-peng Wei National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China School of Materials Science and Engineering Nanyang Technological University639798Singapore

Additive manufacturing technology is highly regarded due to its advantages,such as high precision and the ability to address complex geometric ***,the development of additive manufacturing process is constrained by issues like unclear fundamental principles,complex experimental cycles,and high *** learning,as a novel artificial intelligence technology,has the potential to deeply engage in the development of additive manufacturing process,assisting engineers in learning and developing new *** paper provides a comprehensive overview of the research and applications of machine learning in the field of additive manufacturing,particularly in model design and process ***,it introduces the background and significance of machine learning-assisted design in additive manufacturing *** then further delves into the application of machine learning in additive manufacturing,focusing on model design and process ***,it concludes by summarizing and forecasting the development trends of machine learning technology in the field of additive manufacturing.

关键词： additive manufacturing machine learning material design process optimization intersection of disciplines embedded machine learning