检索结果-南通市图书馆

Computers, Materials & Continua 2024年第4期79卷 1679-1703页

作者： Dingping Chen Zhiheng Zhu Jinyang Fu jilin He college of Mechanical and Electrical Engineering Central South UniversityChangsha410083China Department of Geotechnical Guangdong Hualu Transportation Technology Company LimitedGuangzhou510000China National Engineering Research Center of High-Speed Railway Construction Technology Changsha410075China

The detection of crack defects on the walls of road tunnels is a crucial step in the process of ensuring travel safetyand performing routine tunnel maintenance. The automatic and accurate detection of cracks on the surface of roadtunnels is the key to improving the maintenance efficiency of road tunnels. Machine vision technology combinedwith a deep neural network model is an effective means to realize the localization and identification of crackdefects on the surface of road *** propose a complete set of automatic inspection methods for identifyingcracks on the walls of road tunnels as a solution to the problem of difficulty in identifying cracks during manualmaintenance. First, a set of equipment applied to the real-time acquisition of high-definition images of walls inroad tunnels is designed. Images of walls in road tunnels are acquired based on the designed equipment, whereimages containing crack defects are manually identified and selected. Subsequently, the training and validationsets used to construct the crack inspection model are obtained based on the acquired images, whereas the regionscontaining cracks and the pixels of the cracks are finely labeled. After that, a crack area sensing module is designedbased on the proposed you only look once version 7 model combined with coordinate attention mechanism (CAYOLOV7) network to locate the crack regions in the road tunnel surface images. Only subimages containingcracks are acquired and sent to the multiscale semantic segmentation module for extraction of the pixels to whichthe cracks belong based on the DeepLab V3+ network. The precision and recall of the crack region localizationon the surface of a road tunnel based on our proposed method are 82.4% and 93.8%, respectively. Moreover, themean intersection over union (MIoU) and pixel accuracy (PA) values for achieving pixel-level detection accuracyare 76.84% and 78.29%, respectively. The experimental results on the dataset show that our proposed two-staged

关键词： Road tunnel crack inspection crack area sensing multiscale semantic segmentation CA-YOLO V7 DeepLab V3+

Decoding the inconsistency of six cropland maps in china

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The Crop Journal 2024年第1期12卷 281-294页

作者： Yifeng Cui Ronggao Liu Zhichao Li Chao Zhang Xiao-Peng Song jilin Yang Le Yu Mengxi Chen Jinwei Dong Institute of Geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China university of Chinese Academy of sciences Beijing 100049China Department of Geographical sciences University of MarylandCollege ParkMD 20740USA college of Grassland science and Technology China Agricultural UniversityBeijing 100193China Ministry of Education Ecological Field Station for East Asian Migratory Birds Department of Earth System ScienceInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China Ministry of Education Ecological Field Station for East Asian Migratory Birds Beijing 100084China Tsinghua university(Department of Earth System science)-Xi’an Institute of Surveying and Mapping Joint Research Center for Next-Generation Smart Mapping Beijing 100084China Institute of Remote Sensing and Geographic Information System Peking UniversityBeijing 100871China Department of Forest and Conservation sciences University of British ColumbiaVancouverBCV6T 1Z4Canada

Accurate cropland information is critical for agricultural planning and production,especially in foodstressed countries like *** widely used medium-to-high-resolution satellite-based cropland maps have been developed from various remotely sensed data sources over the past few decades,considerable discrepancies exist among these products both in total area and in spatial distribution of croplands,impeding further applications of these *** factors influencing their inconsistency are also *** this study,we evaluated the consistency and accuracy of six cropland maps widely used in china in circa 2020,including three state-of-the-art 10-m products(i.e.,Google Dynamic World,ESRI Land Cover,and ESA WorldCover)and three 30-m ones(i.e.,GLC_FCS30,GlobeLand 30,and CLCD).We also investigated the effects of landscape fragmentation,climate,and agricultural *** using a ground-truth sample revealed that the 10-m-resolution WorldCover provided the highest accuracy(92.3%).These maps collectively overestimated Chinese cropland area by up to 56%.Up to 37%of the land showed spatial inconsistency among the maps,concentrated mainly in mountainous regions and attributed to the varying accuracy of cropland maps,cropland fragmentation and management practices such as *** work shed light on the promotion of future cropland mapping efforts,especially in highly inconsistent regions.

关键词： Consistency and accuracy 10-and 30 m Cropland mapping Agricultural management china

CSST Dense Star Field Preparation:A Framework for Astrometry and Photometry for Dense Star Field Images Obtained by the china Space Station Telescope(CSST)

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Research in Astronomy and Astrophysics 2024年第7期24卷 158-169页

作者： Yining Wang Rui Sun Tianyuan Deng Chenghui Zhao Peixuan Zhao Jiayi Yang Peng Jia Huigen Liu jilin Zhou college of Electronic Information and Optical Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Astronomy&Space science Nanjing UniversityNanjing 210093China Peng Cheng Lab Shenzhen 518066China

The china Space Station Telescope(CSST)is a telescope with 2 m diameter,obtaining images with high quality through wide-field *** its first observation cycle,to capture time-domain observation data,the CSST is proposed to observe the Galactic halo across different *** data have significant potential for the study of properties of stars and ***,the density of stars in the Galactic center is high,and it is a well-known challenge to perform astrometry and photometry in such a dense star *** paper presents a deep learning-based framework designed to process dense star field images obtained by the CSST,which includes photometry,astrometry,and classifications of targets according to their light curve *** simulated CSST observation data,we demonstrate that this deep learning framework achieves photometry accuracy of 2%and astrometry accuracy of 0.03 pixel for stars with moderate brightness mag=24(i band),surpassing results obtained by traditional ***,the deep learning based light curve classification algorithm could pick up celestial targets whose magnitude variations are 1.7 times larger than magnitude variations brought by Poisson photon *** anticipate that our framework could be effectively used to process dense star field images obtained by the CSST.

关键词： techniques photometric-methods data analysis-astrometry

High-efficiency and flexible photonic microwave harmonic down-converter based on self-oscillation optical frequency combs

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Chinese Optics Letters 2024年第6期22卷 196-204页

作者： Xin Zhang Tao Pu Huatao Zhu Yunshan Zhang Gengze Wu Jin Li jilin Zheng college of Information and Communications National University of Defense TechnologyWuhan 430010China college of Communications Engineering Army Engineering University of PLANanjing 210007China college of Electronic and Optical Engineering&college of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Photonic microwave harmonic down-converters (PMHDCs) based on self-oscillation optical frequency combs (OFCs) are interesting because of their broad bandwidth compared with plain optoelectronic oscillators. In this paper, a high-efficiency and flexible PMHDC is proposed and demonstrated. The properties of the OFC, such as the carrier-to-noise ratio (CNR),bandwidth and free spectral range (FSR), and the influence of optical injection, are investigated. The broadband OFC provides a frequency tunable and high-quality local oscillation (LO), which guarantees flexible down-conversion for the radio frequency (RF) signal. The sideband selective amplification (SSA) effect not only improves the conversion efficiency but also promotes single-sideband modulation. The conversion range can reach 100 GHz. The 12–40 GHz RF signal can be downconverted to intermediate frequency (IF) signals with a high conversion efficiency of 14.9 dB. The fixed 40-GHz RF signal is flexibly down-converted to an IF signal with the frequency from 55.4 to 2129.4 MHz. The phase noise of an IF signal at a frequency offset of 10 kHz is the same as that of the input RF signal. The PMHDC shows great performance and will find applications in radio-over-fiber (RoF) networks, electronic warfare receivers, avionics, and wireless communication systems.

关键词： frequency down-conversion optical frequency comb optical injection optoelectronic oscillation

Mitochondrial DNA analysis of ancient Sampula population in Xinjiang

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Progress in Natural science:Materials International 2007年第8期17卷 927-933页

作者： Xie Chengzhi~(1,2) Li Chunxiang~2 Cui Yinqiu~(1,2) Cai Dawei~(1,2) Wang Haijing~2 Zhu Hong~1 Zhou Hui~(1,2**) (1.Research Center for Chinese Frontier Archaeology,jilin university,changchun 130012,china 2.college of Life science,jilin university,changchun 130023,china) Research Center for Chinese Frontier Archaeology Jilin University Changchun 130012 China college of Life science Jilin University Changchun 130023 China

The archaeological site of Sampula cemetery was located about 14 km to the southwest of the Luo County in Xinjiang Khotan,china,belonging to the ancient Yutian kingdom.14C analysis showed that this cemetery was used from 217 *** 283 A.D. Ancient DNA was analyzed by 364 bp of the mitochondrial DNA hypervariable region I （mtDNA HVR-I）,and by six restriction fragment length polymorphism （RFLP） sites of mtDNA coding *** successfully extracted and sequenced intact stretches of maternally inher- ited mtDNA from 13 out of 16 ancient Sampula *** analysis of mtDNA haplogroup distribution showed that the ancient Sampula was a complex population with both European and Asian *** joining network of U3 sub-haplogroup and multi-dimen- sional scaling analysis all showed that the ancient Sampula had maternal relationship with Ossetian and Iranian.

关键词： ancient DNA mitochondrial DNA Sampula ancient populations

Arnold's theorem on properly degenerate systems with the Russmann nondegeneracy

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science china Mathematics 2005年第12期48卷 1656-1669页

作者： HAN Yuecai & LI Yong college of Mathematics, jilin university, changchun 130012, china college of Mathematics Jilin University Changchun China

In this paper, we investigate the persistence of invariant tori for the nearly in-tegrable Hamiltonian system H(x,y) = h(y) + εp(x,y) + ε2Q(x,y), where h(y) and εp(x,y) satisfy the Russmann non-degenerate condition. Mainly we overcome the difficulties that the order of the parameter E in the perturbation ε2Q(x,y) is not enough and that the measure estimate involves in parts of frequencies with small parameter.

关键词： Arnold’s theorem the Russmann non-degenerate condition.

A software cascading faults model

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science china(Information sciences) 2011年第11期54卷 2454-2458页

作者： LIU YanHeng 1,2,LIU XueLian 3 & WANG Jian 1,2 1 Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education,jilin university,changchun 130012,china 2.college of Computer science and Technology,jilin university,changchun 130012,china 3 college of Software,jilin university,changchun 130012,china Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun China college of Computer science and Technology Jilin University Changchun China college of Software Jilin University Changchun China

Functions and call relations are extracted into nodes and edges,respectively,by which a novel topological model is *** directional edges and the corresponding weight values express the call relations and tightness *** introducing two concepts of function fault-tolerant capability and software fault intensity and by designing a allocation rule on fault-tolerant capability,a cascading fault model is built to explore fault propagation *** on practical software networks show that a weak fault intensity,a small number of initial faults,and a strong fault-tolerant capability can slow down the spreading *** functions with more call relations and more closer tightness contribute more to the stability of the whole system.

关键词： software fault tolerant cascading faults fault-tolerant capability fault intensity

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Modal extension rule

Progress in Natural science:Materials International 2005年第6期15卷 550-558页

作者： WU Xia*, SUN Jigui, LIN Hai and FENG Shasha(college of Computer science and Technology, jilin university, changchun 130012, china Key Laboratory for Symbolic Computation and Knowledge Engineering, jilin university, changchun 130012, china) college of Computer science and Technology Jilin University Changchun 130012 China Key Laboratory for Symbolic Computation and Knowledge Engineering Jilin University Changchun 130012 China

Modal logics are good candidates for a formal theory of agents. The efficiency of reasoning method in modal logics is very important, because it determines whether or not the reasoning method can be widely used in systems based on agent. In this paper, we modify the extension rule theorem proving method we presented before, and then apply it to P-logic that is translated from modal logic by functional transformation. At last, we give the proof of its soundness and completeness.

关键词： theorem proving extension rule modal logics functional transformation.

Construction of EGFP-tagged rBCG of *** and distribution in chickens

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science china(Life sciences) 2009年第3期52卷 278-283页

作者： WANG QiuYue1,LI JianHua1,ZHANG XiChen1,LIU ChengWu2,CAO LiLi1,REN KeYan3,GONG PengTao1,CAI YaNan11 college of animal science and veterinary medicine,jilin university,changchun 130062,china 2 Shenyang Police Dog Training School,Shenyang 110034,china 3 veterinary science Institute of jilin Province,changchun 130062,china college of animal science and veterinary medicine Jilin University Changchun China Shenyang Police Dog Training School Shenyang China veterinary science Institute of jilin Province Changchun China

Chicken coccidiosis is a major parasitic disease with substantial economic burden to the poultry *** green fluorescent protein(EGFP) tagged recombinant Bacille Calmette-Guerin(rBCG),as a fusion protein with coccidian rhomboid antigen was constructed to track rBCG in vivo in chickens in this *** of chickens with one dose of rBCG pMV361-Rho/EGFP induced humoral immune *** colonization of rBCG in liver,spleen,lung,kidney and caecum was observed by laser confocal ***-time quantitative RT-PCR showed a rise expression level of rhomboid protein on the 7th day and a peak on the 14th day and disappearance on the 28th day after *** results have significant implications for the development of rBCG vaccines against avian coccidiosis.

关键词： coccidiosis rBCG EGFP rhomboid laser confocal microscopy real-time RT-PCR