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Snake-worm: A Bi-modal Locomotion Robot

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Journal of Bionic Engineering 2022年第5期19卷 1272-1287页

作者： Zhouwei Du Hongbin Fang Jian Xu School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China Institute of AI and Robotics Fudan UniversityShanghai 200433China Engineering Research Center of AI and Robotics Ministry of EducationFudan UniversityShanghai 20043China Shanghai Engineering Research Center of AI and Robotics Fudan UniversityShanghai 200433China

Inspired by the morphology characteristics and the locomotion mechanisms of the earthworm,and the snakes’morphology characteristics and motivated by the demands for multi-modal locomotion robots in variable working environments,this paper presents a novel bi-modal robot named as Snake-Worm Locomotion Robot(SWL-Robot).Two fundamentally different locomotion mechanisms,the earthworm’s peristaltic rectilinear locomotion and the snake’s lateral undulation,are synthesized in the SWL-Robot design.In detail,the SWL-Robot consists of six earthworm-like body segments interconnected by rotational joints and a head segment equipped with a couple of independently driven wheels.By actuating the segments following a peristaltic wave-like gait,the robot as a whole could perform earthworm-like rectilinear crawling.The robot could also perform snake-like undulatory locomotion driven by differential motions of the wheels at the head segment.To understand the relationship between the design parameters and the robotic locomotion performance,kinematic models of the SWL-Robot corresponding to the two locomotion modes are developed.Rich locomotion behaviors of the SWL-Robot are achieved,including the peristaltic locomotion inside a tube,multiple planar motions on a flat surface,and a hybrid motion that switches between the tube and the flat surface.It shows that the measured trajectories of the SWL-Robot agree well with the theoretical predictions.The SWL-Robot is promising to be implemented in tasks where both tubular and flat environments may be encountered.

关键词： Multi-modal locomotion Peristaltic locomotion Planar locomotion Worm-like robot Snake-like robot

Analysis of the Pull Effect of Local Government Special-Purpose Bond Investment on Economic Growth Under the Input-Output Framework

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Journal of Systems Science and Information 2023年第4期11卷 451-465页

作者： xuguang SUN Jian Xu School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China

In this paper,we discuss the development process of local government special bonds,and the role channels of local government special debt investment in driving China’s economic growth.Based on the specific decomposition of Xinjiang local government special bond investment,this paper uses the non-competitive input-output model for the first time to analyze the net pulling effect of Xinjiang local government special bond investment on Xinjiang’s GDP and employment in 2020.Two measure calibers are set in this paper based on whether the financing costs are considered or not;in addition,we set up four scenarios based on two conditions:Whether to consider retained fun and whether to consider using special-purpose bond investment to leverage social capital.The results show that:1)when financing costs are not considered,the RMB77.4 billion local government special-purpose bonds can push the GDP of Xinjiang to grow by RMB42.27 billion,RMB35.12 billion,RMB77.548billion and RMB69.34 billion respectively under the four scenarios;2)when financing costs are not considered,the number of jobs driven by the RMB77.4 billion local government special-purpose bonds was respectively 372,300,324,500,718,500 and 601,300 in the four scenarios;3)when financing costs are considered,the RMB77.4 billion local government special-purpose bonds can push the GDP of Xinjiang to grow by RMB71.876 billion and RMB64.268 billion under scenario 3)and scenario 4).

关键词： local government special purpose bond investment non-competitive input-output model value-added

Potential Characteristics of Supervisory Board,Company Asset Scale and Irregularity of Listed Companies:Empirical Analysis Based on Heckman Two-Stage Model

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Journal of Systems Science and Information 2023年第2期11卷 179-203页

作者： Yang CHEN Jian Xu School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China

Based on heterogeneity extraction,this paper analyzes four potential characteristics of the supervisory board,they are Individual Heterogeneity of the Supervisory Member(Internal Heterogeneity),Organization Size of the Supervisory Board(Organization Size),Structural Characteristics of the Supervisory Board(Structural Characteristics)and Identity Background of the Supervisory Board(Identity Background);and verifies the impact and action path of the potential characteristics on irregularities.Then,systematically evaluates the micro enterprise organization construction and corporate governance behavior by using the methods of factor analysis and Heckman two-stage model.Empirical research shows that the scale of corporate assets does have an important impact on corporate irregularities and the governance of the board of supervisors.Under the regulation of the company scale,the three potential characteristics:Organization Size,Identity Background and Structural Characteristics have played a significant inhibitory role on irregularities,and the Internal Heterogeneity has no significant effect.When using violation behavior as an alternative variable of supervision performance,the sample selection deviation will be caused by the lack of information disclosure.This paper suggests that we should pay attention to the team of the board of supervisors scientifically and reasonably,weaken the appropriate personalized differences within the board of supervisors,and comprehensively consider the interaction between the company scale,asset quality and the performance of the board of supervisors when formulating the corporate internal management system.

关键词： heterogeneous factors potential characteristics company asset scale factor analysis Heckman two-stage model

Low-degree toroidal modes from the Sumatra-Andaman event observed by superconducting gravimeters

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Geodesy and Geodynamics 2019年第6期10卷 477-484页

作者： Chuang xu Hangtao Yu Guangyu jian Shiqi Deng Boyang Zhou Yihao Wu Department of Surveying Engineering School of Civil and Transportation EngineeringGuangdong University of TechnologyNo.100 Waihuan Xi RoadGuangzhou 510006China State Key Laboratory of Geodesy and Earth’s Dynamics Institute of Geodesy and GeophysicsChinese Academy of SciencesNo.340 Xu Dong AvenueWuhan 430077China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China School of Earth Science and Engineering Hohai UniversityNanjing 210098China

The complex frequencies of the low-degree toroidal modes are helpful in constraining the mantle structure.In the early years,the traditional method to detect the low-degree toroidal modes is seismic approach,which is primarily limited by the horizontal noise of seismometers.Recently,it has been proved that gravity method is competitive.Therefore,we re-estimated or newly estimated the complex frequencies of the toroidal modes below 1.5 mHz excited by the 2004 Sumatra-Andaman event using gravity method in this paper.The results show that(1)The quality factors of0 T5-0 T9 and1 T2-1 T3 are estimated from superconducting gravity data for the first time;(2)The estimated frequencies and quality factors for0 T2-0 T9 and1 T2-1 T3 are consistent with those provided by previous publications,which verifies the correctness and effectiveness of our estimations;(3)The maximum difference of frequencies between our results and those from CPREM is on the order of 0.01 mHz and the maximum difference of quality factors is at the level of 10.

关键词： Low-degree toroidal modes Superconducting gravity data Complex frequency Quality factor

Effects of time-delayed vibration absorber on bandwidth of beam for low broadband vibration suppression

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Applied Mathematics and Mechanics(English Edition) 2023年第10期44卷 1629-1650页

作者： Xiuting SUN Yipeng QU Feng WANG Jian Xu School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China

The effects of time-delayed vibration absorber(TDVA) on the dynamic characteristics of a flexible beam are investigated. First, the vibration suppression effect of a single TDVA on a continuous beam is studied. The first optimization criterion is given,and the results show that the introduction of time-delayed feedback control(TDFC) is beneficial to improving the vibration suppression at the anti-resonance band. When a single TDVA is used, the anti-resonance is located at a specific frequency by the optimum design of TDFC parameters. Then, in order to obtain low-frequency and broad bands for vibration suppression, multiple TDVAs are uniformly distributed on a continuous beam,and the relationship between the dynamic responses and the TDFC parameters is investigated. The obtained relationship shows that the TDVA has a significant regulatory effect on the vibration behavior of the continuous beam. The effects of the number of TDVAs and the nonlinearity on the bandgap variation are discussed. As the multiple TDVAs are applied, according to the different requirements on the location and bandwidth of the effective vibration suppression band, the optimization criteria for the TDFC parameters are given, which provides guidance for the applications of TDVAs in practical projects such as bridge and aerospace.

关键词： time-delayed vibration absorber(TDVA) time-delayed feedback control(TDFC) parameter design criterion broadband vibration suppression

A bibliometric review on stability and reinforcement of special soil subgrade based on CiteSpace

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第2期9卷 223-243页

作者： Haiying Wang Wei Zhang Yingzhi Zhang Jian Xu School of Construction Machinery Chang’an UniversityXi'an 710064China Shaanxi Transportation Holding Group Co. Ltd.Xi'an 710075China School of Management Xi’an University of Science and TechnologyXi'an 710054China

To establish a scientific foundation for further studies and to better understand special soil subgrade research foci and development directions,a visualization analysis of 2601 and 2102 article from 2005 to 2019 was conducted based on the China National Knowledge Infrastructure(CNKI)and Web of Science(WOS)core databases.Time distribution feature,country/region distribution,organization distribution,main source journal distribution,research hotspots and frontier of literature are all analyzed,and the knowledge domain maps are plotted with CiteSpace visualization software.It was found that from 2005 to 2019,the analysis uncovered that China,USA,Australia,Iran and India as the top five most productive countries publishing about subgrade stability and reinforcement with special soil,but results from the USA are the most influential ones in this field,the national/regional quantitative analysis showed that the density of international co-occurrence network is higher than that of China,which indicated that the international research on the subgrade stability and reinforcement with special soil is relatively concentrated,and the CNKI research was focused on dynamic compaction methods,adding CFG pile and geogrid to strengthen the soil subgrade and the WOS researches were focused on the use of geosynthetics to strengthen the subgrade.The current researches of CNKI were revealed to be the compression and deformation characteristics of lightweight foam soil fill subgrade whereas soft soil subgrade problems and numerical analysis methods were the current research foci in the WOS.

关键词： Road engineering Special soil subgrade Research hotspots CiteSpace Visualization analysis

Single-Cell Transcriptome Analysis in Plants:Advances and Challenges

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Molecular Plant 2021年第1期14卷 115-126页

作者： Rahul Shaw Xin Tian Jian Xu Department of Plant Systems Physiology Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJ Nijmegenthe Netherlands Department of Biological Sciences and Centre for Bioimaging Sciences National University of SingaporeSingapore 117543Singapore

The rapid and enthusiastic adoption of single-cell RNA sequencing(scRNA-seq)has demonstrated that this technology is far more than just another way to perform transcriptome analysis.It is not an exaggeration to say that the advent of scRNA-seq is revolutionizing the details of whole-transcriptome snapshots from a tissue to a cell.With this disruptive technology,it is now possible to mine heterogeneity between tissue types and within cells like never before.This enables more rapid identification of rare and novel cell types,simultaneous characterization of multiple different cell types and states,more accurate and integrated understanding of their roles in life processes,and more.However,we are only at the beginning of unlocking the full potential of scRNA-seq applications.This is particularly true for plant sciences,where single-cell transcriptome profiling is in its early stage and has many exciting challenges to overcome.In this review,we compare and evaluate recent pioneering studies using the A rabidopsis root model,which has established new paradigms for scRNA-seq studies in plants.We also explore several new and promising single-cell analysis tools that are available to those wishing to study plant development and physiology at unprecedented resolution and scale.In addition,we propose some future directions on the use of scRNA-seq technology to tackle some of the critical challenges in plant research and breeding.

关键词： bioinformatics pipelines cell types and states plant development and physiology single-cell RNA sequencing single-cell transcriptome analysis

Evidence-based practices in sustainable travel behavior intervention: A knowledge graph-based systematic review

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 293-311页

作者： jian Li Chenjie xu Key Laboratory of Road and Traffic Engineering of the Ministry of Education College of Transportation EngineeringTongji UniversityShanghai 201804China

Sustainable travel behavior intervention is an essential strategy to promote the development of urban transportation.The interventions offer personalized strategies based on certain scenario and participants to promote its effectiveness over hard travel restrictions.However,personalized strategies may also bring about difficulties to identify the actual effect of the measures.Furthermore,based on current practice,to make full use of travel behavior interventions,it is necessary to construct a unified methodological evidencebased framework to assess the reliability and effectiveness of travel behavior intervention studies.In response to these issues,we applied evidence-based knowledge graph to the field of sustainable travel behavior interventions to help decision supporters design sustainable travel behavior interventions wisely and in turn avoid excessive use of hard travel restrictions.We introduced concept of evidence-based practice to conduct a systematic analysis concerning reliability and validity of current full volume empirical studies by dimensions of scenarios,types of interventions and targets.In addition,we took advantage of high extensivity and integrability of knowledge graph to organize evidence-based related elements.Result of the systematic analysis shows that in terms of reliability of evidence,school intervention is the best scenario,knowledge incentive is the best intervention type and promoting public transit and walking proportion are the best targets.Oppositely,the reliability of interventions in workplace,belonging to reward and threat along with aiming at changing travel patterns generally and lowering travel carbon emission need to be enhanced.From the study,various research prospects are raised to promote evidence quality in the field of travel behavior intervention implementation.As a pioneer study,our research contributes to the field of urban transportation in introducing concepts of evidence-based practice and enabling optimization and extension of our achievement via the usage of k

关键词： Evidence-based decision-making Evidence assessment Knowledge graph Travel behavior intervention Sustainable travel

Optimal Frequency Regulation Based on Characterizing the Air Conditioning Cluster by Online Deep Learning

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CSEE Journal of Power and Energy Systems 2022年第5期8卷 1373-1387页

作者： Yeyan xu Liangzhong Yao Siyang Liao Yaping Li Jian Xu Fan Cheng School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China China Electric Power Research Institute Nanjing 210008China China Electric Power Research Institute Beijing 100085China

The air conditioning cluster(ACC)is a potential candidate to provide frequency regulation reserves.However,the effective assessment of the ACC willing reserve capacity is often an obstacle for existing demand response(DR)programs,influenced by incentive prices,temperatures,etc.In this paper,the complex relationship between the ACC willing reserve capacity and its key influence factors is defined as a demand response characteristic(DRC).To learn about DRC along with real-time frequency regulation,an online deep learning-based DRC(ODLDRC)modeling methodology is designed to continuously retrain the deep neural network-based model.The ODL-DRC model trained by incoming new data does not require massive historical training data,which makes it more time-efficient.Then,the coordinate operation between ODL-DRC modeling and optimal frequency regulation(OFR)is presented.A robust decentralized sliding mode controller(DSMC)is designed to manage the ACC response power in primary frequency regulation against any ACC response uncertainty.An ODL-DRC model-based OFR scheme is formulated by taking the learning error into consideration.Thereby,the ODL-DRC model can be applied to minimize the total operational cost while maintaining frequency stability,without waiting for a well-trained model.The simulation cases validate the superiority of the OFR based on characterizing the ACC by online learning,which can capture the real DRC and simultaneously optimize the regulation performance with strong robustness against any ACC response uncertainty and learning error.

关键词： Air conditioning demand response characteristic online deep learning optimal frequency regulation sliding mode control