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混凝土节段梁吊具机械臂辅助对位方法研究

起重运输机械 2022年第18期 36-43页

作者：纪晓宇方之遥肖浩董奇峰中交第二航务工程局有限公司武汉430040 长大桥梁建设施工技术交通行业重点实验室武汉430040 交通运输行业交通基础设施智能制造技术研发中心武汉430040 中交公路长大桥建设国家工程研究中心有限公司武汉430040

预制装配式建造技术是桥梁工程建设领域的主要发展方向之一,节段拼装技术采用离散化的思路解决了大型构件制造、运输和安装的难题,但其施工过程中存在着节段梁吊装次数多、周期长、人工成本高的问题。文中结合混凝土节段梁吊装少人化、... 详细信息

预制装配式建造技术是桥梁工程建设领域的主要发展方向之一,节段拼装技术采用离散化的思路解决了大型构件制造、运输和安装的难题,但其施工过程中存在着节段梁吊装次数多、周期长、人工成本高的问题。文中结合混凝土节段梁吊装少人化、无人化、高效率的实际需求,提出一种具有自动化抓取功能的吊具,并重点研究采用机械臂辅助对位的方法来实现吊具相对节段梁位置的固定和调整。首先介绍了自动化抓取吊具的主要组成部分和功能,其次建立了辅助对位机械臂运动学物理模型,结合应用需求使用几何法进行运动学分析,最后借助虚拟样机和运动分析结果对机械臂辅助对位方法进行了研究。

关键词：节段梁吊具自动化抓取机械臂对位方法

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基于有限元法的浅海移动平台机械结构分析

起重运输机械 2022年第16期 60-65页

作者：吴中正方之遥董奇峰纪晓宇中交第二航务工程局有限公司武汉430040 长大桥梁建设施工技术交通行业重点实验室武汉430040 交通运输行业交通基础设施智能制造技术研发中心武汉300404 中交公路长大桥建设国家工程研究中心有限公司武汉430040

浅海移动平台主体机械结构的机械性能决定了施工平台的可靠性,文中根据工程需求指标,基于有限元法并结合虚拟样机技术对施工平台核心部件进行机械结构静力学分析和模态分析。对悬挂支腿的静力学分析结果表明,极限工况下悬挂支腿最大应... 详细信息

浅海移动平台主体机械结构的机械性能决定了施工平台的可靠性,文中根据工程需求指标,基于有限元法并结合虚拟样机技术对施工平台核心部件进行机械结构静力学分析和模态分析。对悬挂支腿的静力学分析结果表明,极限工况下悬挂支腿最大应力和最大形变均在设计范围以内,其强度和刚度均满足要求;对施工平台主体机械结构的模态分析结果表明,液压站原动机工作时振动频率应小于31.133Hz或大于94.987Hz,平台作业平板与杆件之间应进行局部结构的加强处理。浅海移动平台机械结构静态特性和动态特性的分析研究能够对结构设计和原动机的选型提供理论依据,对提升施工平台的可靠性具有实际意义。

关键词：浅海移动平台有限元法静力学分析模态分析

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浅海移动平台悬挂电液控制系统优化与研究

起重运输机械 2022年第14期 34-39页

作者：董奇峰方之遥吴中正纪晓宇中交第二航务工程局有限公司武汉430040 长大桥梁建设施工技术交通行业重点实验室武汉430040 交通运输行业交通基础设施智能制造技术研发中心武汉430040 中交公路长大桥建设国家工程研究中心有限公司武汉430040

文中针对浅海移动平台悬挂系统响应滞后、控制精度较差的问题,采用理论分析和仿真实验的方法,通过对悬挂电液控制系统工作原理和核心元件的分析,基于电液控制系统对动力元件压力恒定和控制元件高频率响应的实际控制性能要求,将控制阀和... 详细信息

文中针对浅海移动平台悬挂系统响应滞后、控制精度较差的问题,采用理论分析和仿真实验的方法,通过对悬挂电液控制系统工作原理和核心元件的分析,基于电液控制系统对动力元件压力恒定和控制元件高频率响应的实际控制性能要求,将控制阀和液压泵作为主要优化对象,提出了悬挂电液比例位置控制系统优化方案。结合优化需求,根据系统特性搭建了优化后的悬挂电液控制系统物理仿真模型,并基于此模型添加了PID控制器。为验证优化方案的可行性,以阶跃信号为输入信号进行了仿真分析,分析结果表明,优化后的电液控制系统阶跃响应平稳且无超调,响应时间由原来的2 s提升到了0.6 s,满足浅海移动平台调平对悬挂系统的使用要求。

关键词：浅海移动平台悬挂系统电液控制系统优化方案

Latitudinal and elevational patterns of phylogenetic structure in forest communities in China’s mountains

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Science China(Life Sciences) 2020年第12期63卷 1895-1904页

作者： Gheyur Gheyret Yanpei Guo Jingyun fang zhiyao Tang Institute of Ecology College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of EducationPeking UniversityBeijing 100871China

The phylogenetic structure incorporates both ecological and evolutionary processes to explain assembly of a local *** "phylogenetic niche conservatism"(PNC) hypothesis suggests that distributions of species along environmental gradients reflect both ancestral traits and ecological fitness of individual species. The temperature is generally regarded to change in similar ways along both latitudinal and elevational gradients but with different historical contingence. Therefore, comparing the latitudinal and elevational patterns of phylogenetic structure of communities is of help to depict the effects of ecological and evolutionary processes in shaping the community assembly. In this study, we explored the latitudinal, elevational and climatic patterns of phylogenetic structure of 569 angiosperm tree communities from 38 mountains across China. We found a larger mean abundance-weighted net relatedness index(NRI) than the presence/absence-based NRI;and the NRI decreased when the species pool downscaled from the full pool to county-level pool. The mean family age and phylogenetic species evenness decreased with latitude, and increased with temperature of the coldest month and precipitation;whilst NRI increased with latitude, and decreased with mean temperature of the coldest month. In most mountains, NRI, mean family age and phylogenetic species evenness showed non-significant trends along the elevational gradient. Our results support the main predictions of PNC for the latitudinal gradient, i.e., species tend to be more phylogenetically related to each other and clades are younger in temperate environments,compared to those in tropical environments. We suggested that independent species pools and abundance should be incorporated in analysis to fully represent the phylogenetic structure of communities.

关键词： community assembly phylogenetic niche conservatism phylogenetic structure environmental filtering species abundance species pool

Life forms affect beta-diversity patterns of larch forests in China

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Plant Diversity 2024年第1期46卷 49-58页

作者： Wenjing fang Qiong Cai Chengjun Ji Jiangling Zhu zhiyao Tang Jingyun fang School of Ecology and Environmental Science Yunnan UniversityKunming 650091China Department of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China

Beta-diversity reflects the spatial changes in community species composition which helps to understand how communities are assembled and biodiversity is formed and maintained. Larch(Larix) forests, which are coniferous forests widely distributed in the mountainous and plateau areas in North and Southwest China, are critical for maintaining the environmental conditions and species diversity. Few studies of larch forests have examined the beta-diversity and its constituent components(species turnover and nestedness-resultant components). Here, we used 483 larch forest plots to determine the total betadiversity and its components in different life forms(i.e., tree, shrub, and herb) of larch forests in China and to evaluate the main drivers that underlie this beta-diversity. We found that total betadiversity of larch forests was mainly dependent on the species turnover component. In all life forms,total beta-diversity and the species turnover component increased with increasing geographic, elevational, current climatic, and paleoclimatic distances. In contrast, the nestedness-resultant component decreased across these same distances. Geographic and environmental factors explained 20%-25% of total beta-diversity, 18%-27% of species turnover component, and 4%-16% of nestedness-resultant component. Larch forest types significantly affected total beta-diversity and species turnover component. Taken together, our results indicate that life forms affect beta-diversity patterns of larch forests in China, and that beta-diversity is driven by both niche differentiation and dispersal limitation. Our findings help to greatly understand the mechanisms of community assemblies of larch forests in China.

关键词： Beta-diversity Species turnover Nestedness-resultant Geographic distance Climatic distance Larch forest

Optimization of Face Recognition System Based on Azure IoT Edge

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Computers, Materials & Continua 2019年第9期61卷 1377-1389页

作者： Shen Li fang Liu Jiayue Liang Zhenhua Cai zhiyao Liang Sun Yat-sen University Guang Zhou510000China The Macao University of Science and Technology 999078Macao

With the rapid development of artificial intelligence,face recognition systems are widely used in daily *** recognition applications often need to process large amounts of image *** the accuracy and low latency is critical to face recognition *** analyzing the two-tier architecture“client-cloud”face recognition systems,it is found that these systems have high latency and network congestion when massive recognition requirements are needed to be responded,and it is very inconvenient and inefficient to deploy and manage relevant applications on the edge of the *** paper proposes a flexible and efficient edge computing accelerated *** offloading part of the computing tasks to the edge server closer to the data source,edge computing resources are used for image preprocessing to reduce the number of images to be transmitted,thus reducing the network transmission ***,the application code does not need to be rewritten and can be easily migrated to the edge *** evaluate our schemes based on the open source Azure IoT Edge,and the experimental results show that the three-tier architecture“Client-Edge-Cloud”face recognition system outperforms the state-of-art face recognition systems in reducing the average response time.

关键词： Face recognition edge computing azure iot edge computation offloading

Ensemble Learning Based on GBDT and CNN for Adoptability Prediction

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Computers, Materials & Continua 2020年第11期65卷 1361-1372页

作者： Yunfan Ye fang Liu Shan Zhao Wanting Hu zhiyao Liang School of Design Hunan UniversityChangsha410082China College of Computer National University of Defense TechnologyChangsha410073China Canvard College Beijing Technology and Business UniversityBeijing100037China School of Science and Technology Macao University999078Macao

By efficiently and accurately predicting the adoptability of pets,shelters and rescuers can be positively guided on improving attraction of pet profiles,reducing animal suffering and *** prediction methods usually only used a single type of content for ***,many pets contain not only textual content,but also *** make full use of textual and visual information,this paper proposed a novel method to process pets that contain multimodal *** employed several CNN(Convolutional Neural Network)based models and other methods to extract features from images and texts to obtain the initial multimodal representation,then reduce the dimensions and fuse ***,we trained the fused features with two GBDT(Gradient Boosting Decision Tree)based models and a Neural Network(NN)and compare the performance of them and their *** evaluation result demonstrates that the proposed ensemble learning can improve the accuracy of prediction.

关键词： Adoptability of pets multimodal representation CNN GBDT ensemble learning

Feature Selection Method Based on Class Discriminative Degree for Intelligent Medical Diagnosis

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Computers, Materials & Continua 2018年第6期55卷 419-433页

作者： Shengqun fang Zhiping Cai Wencheng Sun Anfeng Liu fang Liu zhiyao Liang Guoyan Wang College of Computer National University of Defense TechnologyChangsha 410073China Computer Science and Technology Central South UniversityChangsha 999078China School of Data and Computer Science Sun Yat-sen UniversityGuangzhou 510006China Faculty of Information Technology Macao University of Science and TechnologyMacao 410073MO. Xuzhou University of Technology Xuzhou 221002China

By using efficient and timely medical diagnostic decision making,clinicians can positively impact the quality and cost of medical ***,the high similarity of clinical manifestations between diseases and the limitation of clinicians’knowledge both bring much difficulty to decision making in ***,building a decision support system that can assist medical staff in diagnosing and treating diseases has lately received growing attentions in the medical *** this paper,we employ a multi-label classification framework to classify the Chinese electronic medical records to establish corresponding relation between the medical records and disease categories,and compare this method with the traditional medical expert system to verify the *** select the best subset of patient features,we propose a feature selection method based on the composition and distribution of symptoms in electronic medical records and compare it with the traditional feature selection methods such as chi-square *** evaluate the feature selection methods and diagnostic models from two aspects,false negative rate(FNR)and *** experiments have conducted on a real-world Chinese electronic medical record *** evaluation results demonstrate that our proposed feature selection method can improve the accuracy and reduce the FNR compare to the traditional feature selection methods,and the multi-label classification framework have better accuracy and lower FNR than the traditional expert system.

关键词： Medical expert system EMR multi-label classification feature selection class discriminative degree

Global patterns and climatic drivers of above-and belowground net primary productivity in grasslands

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Science China(Life Sciences) 2021年第5期64卷 739-751页

作者： Yuanfeng Sun Yuanhe Yang Xia Zhao zhiyao Tang Shaopeng Wang Jingyun fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Understanding patterns and determinants of net primary productivity(NPP)in global grasslands is ongoing challenges,especially for belowground NPP(BNPP)and its fraction(fBNPP).By developing a comprehensive field-based dataset,we revealed that,along with gradients of mean annual precipitation,actual evapotranspiration,and aridity,aboveground NPP(ANPP),BNPP,and total NPP(TNPP)exhibited hump-shaped patterns,whereas fBNPPshowed an opposite *** and TNPP showed positive correlations with mean annual temperature,but fBNPPwas negatively correlated with *** relationship between BNPP and climatic factors was considerably weak,indicating that BNPP was relatively stable regardless of the climate *** also observed that the sensitivities of ANPP and BNPP to interannual temperature variability and those of BNPP to interannual precipitation fluctuations exhibited large variations among different study sites,and differed from those at the spatial *** contrast,the temporal sensitivities of ANPP to interannual precipitation variability were highly similar across all the individual sites and much smaller than those at the spatial ***,these results highlight that precipitation,temperature and evapotranspiration all play vital roles in shaping ANPP pattern and its partitioning to belowground and that the patterns of BNPP along climatic gradients do not mirror those of the ANPP.

关键词： net primary productivity productivity partition climate change grasslands precipitation temperature