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Satellite Navigation 2020年第1期1卷 68-80页

作者： Xiangdong An xiaolin meng Weiping Jiang GNSS Research Center Wuhan University129 Luoyu RoadWuhan 430079China Nottingham Geospatial Institute University of NottinghamNottingham NG72TUUK.

Precise point positioning(PPP)is famous for its capability of high-precision positioning with just one station as long as the receiver can receive global navigation satellite system(GNSS)*** the rapid development of BDS and Galileo,the number of available satellites for positioning has increased *** addition,GPS III,GLONASS-K,BDS,and Galileo satellites can transmit triple-frequency *** potentials of multi-constellation GNSS PPP requires further analysis on a global ***,we selected 96 multi-GNSS experiment(MGEX)stations with a global distribution and used 1 week’s data to assess the PPP *** results show that the PPP based on multi-frequency raw observations with spatial and temporal constraints has better performance than PPP using dual-frequency ionospheric-free *** main contribution of multi-constellation GNSS PPP is to shorten the convergence *** convergence time for GPS PPP is approximately 40 min,which can be shortened to less than 20 min in multi-GNSS *** convergence,the positioning accuracy of multi-GNSS PPP is improved by 0.5 to 1.0 cm compared with GPS or GLONASS *** positioning accuracy of multi-GNSS could be further improved in the future with the BDS and Galileo precise products of orbits,clock and phase center offset/variation.

关键词： Precise point positioning Multi-frequency and multi-constellation GNSS PPP convergence Multi-GNSS experiment

Assessment of tomographic window and sampling rate efects on GNSS water vapor tomography

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Satellite Navigation 2023年第1期4卷 155-166,I0005页

作者： Fei Yang Yilin Sun xiaolin meng Jiming Guo Xu Gong College of Geoscience and Surveying Engineering China University of Mining and Technology-BeijingBeijing 100083China College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China

The ground-based Global Navigation Satellite System(GNSS)water vapor tomography is increasingly important in GNSS *** the multi-GNSS and more ground-based GNSS sites can be incorporated into the regional water vapor tomographic model,determining the tomographic window and sampling rate is crucial for the modelling of the water vapor *** two factors afect not only the number of available signal rays from the satellites,but also the number of tomographic voxels crossed by the signal *** study uses Hong Kong as the research area to explore the impact of 12 schemes with diferent tomographic window and sampling rate on the three water vapor tomography methods,including Least squares,Kalman fltering,and Multiplicative Algebraic Reconstruction Technique(MART).Numerical results show that the tomographic results with the three methods get better as the width of the tomographic window decreases and the sampling rate increases in these 12 schemes,and it is found that the Least squares method is most afected by the two factors,followed by Kalman fltering and MART *** is recommended to set a tomographic window width of 10 min and a sampling rate of 300 s in a GNSS water vapor tomographic experiment with dense GNSS site like Hong Kong.

关键词： GNSS meteorology Water vapor Tomography

A versatile 3D-printable hydrogel for antichondrosarcoma,antibacterial,and tissue repair

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Journal of Materials Science & Technology 2023年第5期136卷 200-211页

作者： Wenxiang Zhu Zheng Zhou Yuting Huang Hairong Liu Ning He Xiaolong Zhu Xiaoxiao Han Dengming Zhou Xuanchu Duan Xin Chen Yahui He xiaolin meng Shuai Zhu College of Materials Science and Engineering Hunan UniversityChangsha 410082China College of Biology Hunan UniversityChangsha 410082China State Key Laboratory of Advanced Design and Manufacture for Vehicle Body Hunan UniversityChangsha 410082China Department of Ophthalmology The Second Xiangya HospitalCentral South UniversityChangsha 410011China Aier Glaucoma Institute Changsha 410000China Aier School of Ophthalmology Central South UniversityChangsha 410000China Changsha Aier Eye Hospital Aier Eye Hospital GroupChangsha 410000China

Following operative treatment of chondrosarcoma,post-surgery tissue reconstruction may be confronted with daunting challenges,including the delayed self-repair of defective tissue,tumor recurrence,and bac-terial *** overcome these challenges,a methacrylic anhydride(MA)modified sericin(SerMA)solution mixed with procyanidins(PC)loaded polydopamine(PDA)modified ZIF-8(PC@ZIF-8@PDA)nanoparticles to form a multifunctional PC@ZIF-8@PDA/SerMA hydrogel after exposure under blue *** products with pre-designed shapes were printed out by using the SerMA solution carrying PC@ZIF-8@PDA nanoparticles and chondrocytes,indicating that PC@ZIF-8@PDA/SerMA hydrogels with personalized shapes can be fabricated via 3D *** PC@ZIF-8@PDA/SerMA hydrogel is able to kill chondrosarcoma cells and bacteria,like Staphylococcus aureus(***),and Escherichia coli(***),by its photothermal activity combined with near-infrared radiation(NIR).The PC@ZIF-8@PDA/SerMA hydrogel exhibited an antioxidative activity and a good biocompatibility and was easily monitored by its florescent and photoacoustic *** articular cartilage defects were efficiently repaired by PC@ZIF-8@PDA/SerMA hydrogels with encapsulated corresponding autologous chondrocytes,and mice skin burning wounds were swiftly regenerated by applying this ***,the PC@ZIF-8@PDA/SerMA hydrogel can be potentially applied to the clinic treatment of chondrosarcoma and tissue defect repair after chondrosarcoma resection due to its multifunction in the future.

关键词： Hydrogel Sericin ZIF-8 Chondrosarcoma Cartilage repair

Scheme of adaptive polarization filtering based on Kalman model

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Journal of Systems Engineering and Electronics 2006年第1期17卷 13-18页

作者： Song Lizhong Qi Haiming Qiao xiaolin meng Xiande Inst. of Electronic Engineering Harbin Inst. of Technology Harbin 150001 P. R. China

A new kind of adaptive polarization filtering algorithm in order to suppress the angle cheating interference for the active guidance radar is presented. The polarization characteristic of the interference is dynamically tracked by using Kalman estimator under variable environments with time. The polarization filter parameters are designed according to the polarization characteristic of the interference, and the polarization filtering is finished in the target cell. The system scheme of adaptive polarization filter is studied and the tracking performance of polarization filter and improvement of angle measurement precision are simulated. The research results demonstrate this technology can effectively suppress the angle cheating interference in guidance radar and is feasible in engineering.

关键词： guidance radar polarization adaptive filter Kalman filtering interference suppression.

Development and evaluation of the refined zenith tropospheric delay(ZTD)models

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Satellite Navigation 2021年第1期2卷 296-304页

作者： Fei Yang xiaolin meng Jiming Guo Debao Yuan Ming Chen College of Geoscience and Surveying Engineering China University of Mining and Technology-Beijing100083 BeijingChina Global Geospatial Engineering Ltd. The Sino-UK Geospatial Engineering Centre18 Radford Bridge RoadNottingham NG81NAUK School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan 430079China National Geomatics Center of China Beijing 100830China.

The tropospheric delay is a significant error source in Global Navigation Satellite System(GNSS)positioning and *** is usually projected into zenith direction by using a mapping *** is particularly important to establish a model that can provide stable and accurate Zenith Tropospheric Delay(ZTD).Because of the regional accuracy difference and poor stability of the traditional ZTD models,this paper proposed two methods to refine the Hopfield and Saastamoinen ZTD *** is by adding annual and semi-annual periodic terms and the other is based on Back-Propagation Artificial Neutral Network(BP-ANN).Using 5-year data from 2011 to 2015 collected at 67 GNSS reference stations in China and its surrounding regions,the four refined models were *** tropospheric products at these GNSS stations were derived from the site-wise Vienna Mapping Function 1(VMP1).The spatial analysis,temporal analysis,and residual distribution analysis for all the six models were conducted using the data from 2016 to *** results show that the refined models can effectively improve the accuracy compared with the traditional *** the Hopfield model,the improvement for the Root Mean Square Error(RMSE)and bias reached 24.5/49.7 and 34.0/52.8 mm,*** values became 8.8/26.7 and 14.7/28.8 mm when the Saastamoinen model was refined using the two *** exploration is conducive to GNSS navigation and positioning and GNSS meteorology by providing more accurate tropospheric prior information.

关键词： GNSS Tropospheric delay ZTD Refined model ANN

Towards Data-Driving Multi-View Evaluation Framework for Scratch

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Tsinghua Science and Technology 2024年第2期29卷 517-528页

作者： xiaolin Chai Yan Sun Yan Gao Department of Computer Science Beijing University of Posts and TelecommunicationBeijing 100876China Intellectual Property Institute Shandong Polytechnic CollegeJining 272067China

As one of the most popular visual programming languages,Scratch has a lot of evaluation around *** evaluation can help programmers understand their projects *** the same time,it can also provide a reference for them to browse other projects in the online *** of the existing evaluations on Scratch are carried from three perspectives:Computational Thinking(CT)ability,visual presentation aesthetics,and code *** them,the assessment of CT and code quality is mainly carried out from the program script,while the evaluation of visual aesthetics is analyzed from the perspective of image sequences generated by project *** single-view evaluation focuses on the performance of a program in a certain aspect and is *** this paper,we propose a multi-view evaluation framework to integrate various evaluations using different *** quantitatively analyze the assessment of different views driven by *** with overall evaluations that represent human opinions,we analyze their differences and *** experiments,we determine the weights of different integration policies,the proposed multi-view evaluation method can generate evaluation results similar to human opinions.

关键词： Scratch Computational Thinking(CT) visual aesthetic static analysis integration policy machine learning

First results of BDS positioning for LBS applications in the UK

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Satellite Navigation 2021年第1期2卷 111-129页

作者： Yan Xia xiaolin meng Yusong Yang Shuguo Pan Qing Zhao Wang Gao School of Instrument Science and Engineering Southeast UniversityNanjing 210096China Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology Ministry of EducationNanjing 210096China Nottingham Geospatial Institute The University of NottinghamNottingham NG72TUUK Global Geospatial Engineering Ltd./Sino-UK Geospatial Engineering Centre Radford Bridge RoadNottingham NG81NAUK State Key Laboratory of Media Convergence Production Technology and Systems Beijing 100031China School of Transportation Southeast UniversityNanjing 210096China.

The last satellite of BeiDou Navigation Satellite System with Global Coverage(BDS-3)constellation was successfully launched on June 23rd,2020,and the entire system began to provide Positioning,Navigation,and Timing(PNT)services *** evaluated the performance of location services using BDS with a smartphone that can track the Global Navigation Satellite System(GNSS)satellites in Nottingham,*** static and kinematic experiments were conducted in an open meadow and a lakeside route covered by trees,*** results show that BDS has good visibility,and its overall signal carrier-to-noise density ratio(C/N0)is comparable to that of Global Positioning System(GPS).The average C/N0 of BDS-3 satellites with elevation angles above 45°on B1 band is the highest among all systems,reaching 40.0 dB·*** noise level of the BDS pseudorange measurements is within 0.5 m,and it has a good consistency among *** the static experiment,the standard deviations of BDS position-ing in the east,north and up directions are 1.09,1.16,and 3.02 m,respectively,and the R95 value of the horizontal position is 2.88 *** harsh environments,the number of BDS satellites tracked by the smartphone is susceptible to environmental *** bias Root Mean Squares(RMS)in the three directions of the whole kinematic positioning are 6.83,6.68,11.67 m,in which the positioning bias RMS values in a semi-open environment are only 2.81,1.11,3.29 ***,the inclusion of BDS in multiple GNSS systems can significantly improve the positioning *** study intends to provide a reference for the further improvements of BDS global PNT services,particularly for Location-Based Services(LBS).

关键词： BDS Android smartphone Observation quality LBS UK

Motion Planning for Autonomous Driving with Real Traffic Data Validation

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 74-86页

作者： Wenbo Chu Kai Yang Shen Li xiaolin Tang Western China Science City Innovation Center of Intelligent and Connected Vehicle Chongqing 400044China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China School of Civil Engineering Tsinghua UniversityBeijing 100084China

Accurate trajectory prediction of surrounding road users is the fundamental input for motion planning,which enables safe autonomous driving on public *** this paper,a safe motion planning approach is proposed based on the deep learning-based trajectory prediction *** begin with,a trajectory prediction model is established based on the graph neural network(GNN)that is trained utilizing the INTERACTION ***,the validated trajectory prediction model is used to predict the future trajectories of surrounding road users,including pedestrians and *** addition,a GNN prediction model-enabled motion planner is developed based on the model predictive control ***,two driving scenarios are extracted from the INTERACTION dataset to validate and evaluate the effectiveness of the proposed motion planning approach,i.e.,merging and roundabout *** results demonstrate that the proposed method can lower the risk and improve driving safety compared with the baseline method.

关键词： Trajectory prediction Graph neural network Motion planning INTERACTION dataset

Experimental Study of Temperature Control Based on Composite Phase Change Materials during Charging and Discharging of Battery

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Journal of Thermal Science 2024年第2期33卷 578-590页

作者： LI xiaolin WANG Jun CAO Wenxiang ZHANG Xuesong School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China

This study is to utilize the heat-absorbing and releasing capabilities of phase change materials(PCM)to regulate the surface temperature fluctuations of batteries during charging and *** goal is to keep the battery within the optimal operating temperature *** impact of PCM thickness and phase change temperature on battery temperature is investigated by encircling a cylindrical battery with a PCM *** improve the thermal conductivity of PCM,expanded graphite(EG) is added to make a composite phase change material(CPCM),and the effects of various EG mass ratios on battery surface temperature and CPCM utilization level are *** findings indicate that increasing PCM thickness effectively extends temperature control time,but its impact is *** difference in phase change temperature of PCM controls the battery temperature in different temperature *** phase change temperatures are unsuitable for controlling battery temperature in high temperature *** addition of EG enhances the thermal conductivity of PCM,leading to further control of battery *** results show that the addition of 6%(mass ratio) EG to CPCM extends the effective temperature control time by 11 min and improves by 28% compared to a single *** CPCM utilization is also more satisfactory and achieved a balance between heat storage and thermal conductivity in a battery thermal management system(BTMS) based on PCM.

关键词： phase change material expanded graphite thermal management system effective control time

How Does the Government Facilitate the Co-Production of Digital Public Safety Services?——Based on Empirical Evidence from Shenzhen

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Social Sciences in China 2024年第2期45卷 113-134页

作者： Wu xiaolin Zhou Enlai School of Government Nankai University

The application of big data technology provides support for the co-production of public safety *** research often focuses on how technology influences co-production,but lacks attention to the key actors that drive co-production and the mechanisms that facilitate *** study examines the role of government in the digital co-production of public safety services,using the practice of Shenzhen as a case *** has built 125 information systems based on over 100 billion pieces of big data,forming a model of digital safety service *** study reveals three types of digital co-production,characterized by"government-business joint planning,passive participation of businesses and the public,and active cooperation among government,businesses,and the public"in the"design-production-application"*** study shows that the government is not only a co-producer but also a proactive actor in activating the willingness of non-governmental entities to *** governments mobilize non-governmental participation through three mechanisms:empowerment,profit enhancement,and value ***"power-interest-value"paradigm is applicable for analyzing the co-production of public services and helps to explain the transformation mechanisms of co-production behavior.

关键词： public safety co-production smart emergency response digital public safety