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FMCW-InISAR imaging for high-speed target based on bistatic configuration

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Science China(Technological Sciences) 2020年第8期63卷 1452-1469页

作者： WANG Yong RONG JiaJia ZhanG QingXiang han tao Research Institute of Electronic Engineering Technology Harbin Institute of TechnologyHarbin 150001China

Interferometric inverse synthetic aperture radar(InISAR)imaging has been proved to be a powerful means for obtaining threedimensional(3-D)space shape of noncooperative *** modulated continuous wave(FMCW)InISAR(FMCWInISAR)has unique advantages of low power,low cost,and small volume compared with traditional coherent pulsed ***,FMCW-InISAR imaging has two additional issues to consider,the one is the invalidation of the assumption of stop&go,which is caused by the relatively long sweep interval of FMCW;the other is the isolation of the transmitting and receiving antennas,which is the inherent issue of the transmitter-receiver community radar *** solve these two problems,a bistatic FMCW-InISAR imaging algorithm for high-speed targets is proposed in this *** improving the isolation of the transmitting and receiving antennas,a bistatic configuration based FMCW-InISAR system is *** to the characteristics of bistatic,a bistatic equivalent motion model and corresponding signal model are *** the assumption of stop&go is invalid in the case of FMCW,indicating that the target cannot be viewed as motionless during a sweep repetition interval(SRI),a parametric estimation based quadratic phase factor(QPF)compensation method is investigated to eliminate the range walk caused by the radial motion of the target during the *** addition,considering the farfield trait of the target and combining the traditional InISAR imaging process,a combined QPF compensation technique is proposed to reduce the computational burden of the ***,the effectiveness and the robustness of the proposed algorithm are evaluated by some simulations.

关键词： interferometric inverse synthetic aperture radar(InISAR) frequency modulated continuous wave(FMCW) bistatic configuration radial motion compensation high-speed target imaging

Breakdown of Landau Fermi liquid theory： Restrictions on the degrees of freedom of quantum electrons

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Frontiers of physics 2018年第2期13卷 119-137页

作者： Yue-Hua Su han-tao Lu Department of Physics Yantai University Yantai 264005 China Center for Interdisciplinary Studies Lanzhou University Lanzhou 730000 China

One challenge in contemporary condensed matter physics is to understand unconventional electronic physics beyond the paradigm of Landau Fermi-liquid theory. Here, we present a perspective that posits that most such examples of unconventional electronic physics stem from restrictions on the degrees of freedom of quantum electrons in Landau Fermi liquids. Since the degrees of freedom are deeply connected to the system＇s symmetries and topology, these restrictions can thus be realized by external constraints or by interaction-driven processes via the following mechanisms：（i） symmetry breaking, （ii） new emergent symmetries, and （iii） nontrivial topology. Various examples of unconventionM elec- tronic physics beyond the reach of traditional Landau Fermi liquid theory are extensively investigated from this point of view. Our perspective yields basic pathways to study the breakdown of Landau Fermi liquids and also provides a guiding principle in the search for novel electronic systems and devices.

关键词： breakdown of the Landau Fermi liquids degrees of freedom symmetry topology

Infinitely Many Solutions for Schrödinger–Choquard–Kirchhoff Equations Involving the Fractional p-Laplacian

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Acta Mathematica Sinica,English Series 2021年第2期37卷 315-332页

作者： Li WANG tao han Ji Xiu WANG College of Science East China Jiaotong UniversityNanchang 330013P.R.China School of Mathematics and Statistics Hubei University of Arts and ScienceXiangyang 441053P.R.China

In this article,we show the existence of infinitely many solutions for the fractional p-Laplacian equations of Schrödinger–Kirchhoff type equation M([u]_(s,p)^(p))(−Δ)_(p)^(s)u+V(x)|u|^(p−2)u=λ(Iα∗|u|^(p_(s,α)^(∗)))|u|^(p_(s,α)^(∗)−2)u+βk(x)|u|^(q−2)u,x∈R^(N),where(−Δ)s p is the fractional p-Laplacian operator,[u]s,p is the Gagliardo p-seminorm,0

关键词： Schrödinger–Choquard–Kirchhoff type fractional p-Laplacian variational methods critical Sobolev exponent

A Micro Perspective of Research Dynamics Through“Citations of Citations”Topic Analysis

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Journal of Data and Information Science 2020年第4期5卷 19-34页

作者： Xiaoli Chen tao han National Science Library Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Purpose:Research dynamics have long been a research *** is a macro perspective tool for discovering temporal research trends of a certain discipline or subject.A micro perspective of research dynamics,however,concerning a single researcher or a highly cited paper in terms of their citations and“citations of citations”(forward chaining)remains ***/methodology/approach:In this paper,we use a cross-collection topic model to reveal the research dynamics of topic disappearance topic inheritance,and topic innovation in each generation of forward ***:For highly cited work,scientific influence exists in indirect *** modeling can reveal how long this influence exists in forward chaining,as well as its *** limitations:This paper measures scientific influence and indirect scientific influence only if the relevant words or phrases are borrowed or used in direct or indirect *** or semantically similar concept may be neglected in this *** implications:This paper demonstrates that a scientific influence exists in indirect citations through its analysis of forward *** can serve as an inspiration on how to adequately evaluate research ***:The main contributions of this paper are the following three ***,besides research dynamics of topic inheritance and topic innovation,we model topic disappearance by using a cross-collection topic ***,we explore the length and character of the research impact through“citations of citations”content ***,we analyze the research dynamics of artificial intelligence researcher Geoffrey Hinton’s publications and the topic dynamics of forward chaining.

关键词： Research dynamics Forward chaining Topic model Scientific influence Citations content analysis

Test research on sticking mechanism during hot rolling of SUS 430 ferritic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 573-578页

作者： Jun-xian Liu Yong-jun Zhang Jing-tao han School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The sticking phenomenon during hot rolling of SUS 430 ferritic stainless steel was investigated by means of a two-disc type high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel （HiCr） and high-speed steel （HSS） rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average surface roughnesses （Ra） of HiCr and HSS rolls change from 0.502 and 0.493 μm at the initial stage to 0.837 and 0.530 μm at the saturation stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more benefi- cial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.

关键词： ferritic steel stainless steel hot rolling sticking rolls

El Ni?o/Southern Oscillation during the 4.2 ka event recorded by growth rates of corals from the North South China Sea

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Acta Oceanologica Sinica 2020年第1期39卷 110-117页

作者： Shaohua Dang Kefu Yu Shichen tao tao han Huiling Zhang Wei Jiang Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi UniversityNanning 530004China Coral Reef Research Center of China Guangxi UniversityNanning 530004China School of Marine Sciences Guangxi UniversityNanning 530004China South China Sea Institute of Oceanology Chinese Academy of SciencesGuangzhou 510301China College of Ocean Engineering Guangdong Ocean UniversityZhanjiang 524088China

The 4.2 ka event that occurred during the period from 4 500–3 900 a BP was characterized by cold and dry climates and resulted in the collapse of civilizations around the world. The cause of this climatic event, however, has been under debate. We collected four corals(Porites lutea) from Yongxing Island, Xisha Islands, South China Sea, dated them with the U-series method, and measured the annual coral growth rates using X-ray technology. The dating results showed that the coral growth ages were from 4 500–3 900 a BP, which coincide well with the period of the4.2 ka event. We then reconstructed annual sea surface temperature anomaly(SSTA) variations based on the coral growth rates. The growth rate-based SSTA results showed that the interdecadal SSTA from 4 500–3 900 a BP was lower than that during modern times(1961–2008 AD). A spectral analysis showed that the SSTA variations from4 500–3 900 a BP were under the influence of El Nino-Southern Oscillation(ENSO) activities. From 4 500–4 100 a BP, the climate exhibited La Nina-like conditions with weak ENSO intensity and relatively stable and lower SSTA amplitudes. From 4 100–3 900 a BP, the climate underwent a complicated period of ENSO variability and showed alternating El Nino-or La Nina-like conditions at interdecadal time scales and large SSTA amplitudes. We speculate that during the early and middle stages of the 4.2 ka event, the cold climate caused by weak ENSO activities largely weakened social productivity. Then, during the end stages of the 4.2 ka event, the repeated fluctuations in the ENSO intensity caused frequent extreme weather events, resulting in the collapse of civilizations worldwide. Thus, the new evidence obtained from our coral records suggests that the 4.2 ka event as well as the related collapse of civilizations were very likely driven by ENSO variability.

关键词： 4.2 ka event ENSO variability SSTA coral growth rate Xisha Islands

Extraction and imaging of indicator elements for non-destructive,in-situ,fast identification of adverse geology in tunnels

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International Journal of Mining Science and Technology 2023年第12期33卷 1437-1449页

作者： Fumin Liu Peng Lin Zhenhao Xu Ruiqi Shao tao han School of Qilu Transportation Shandong UniversityJinan 250061China Geotechnical and Structural Engineering Research Center Shandong UniversityJinan 250061China

The lag in quantitative methods and detection techniques for geologic information has resulted in time-consuming and human-experienced geologic analysis in *** indicators of rocks can be used to identify adverse geology and to explain the intrinsic causes of damage to normal *** study proposes a method to identify adverse geology by extracting and imaging the indicator *** mapping relationship between rock components and geologic bodies is quickly determined by indicator element extraction based on factor analysis,and then the data are gridded for image *** location and size of the target adverse geology are visually identified through the distribution images of the indicator elements,thus reducing data dimensions and analysis time.A non-destructive,in-situ and fast element detection technique in tunnels was adopted to speed up the process of geology *** accuracy of the detection was validated by comparing field and laboratory test *** study further confirms and refines the previous research,and the results provide references for geological,mining and underground projects.

关键词： Adverse geology identification Indicator elements Rock geochemistry Tunnel engineering Geological analysis

Carbon efficiency modeling and optimization of solar-powered cellular networks

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Science China(Information Sciences) 2024年第5期67卷 228-243页

作者： Yuxi ZHAO Xiaohu GE Wen YAN tao han Yi ZHONG School of Electronic Information and Communications Huazhong University of Science and Technology Huawei Technology Co. Ltd.

As wireless communication traffic experiences rapid growth, the carbon emissions caused by the communication industry are also on the rise. To achieve “carbon neutrality”, researchers are considering the use of renewable energy sources to power cellular networks, thereby reducing carbon emissions. However, a challenge arises when using renewable energy, specifically owing to the unpredictable nature of both the energy consumption of the cellular network and the power generation from renewable sources. This inconsistency results in low renewable energy utilization and reduced carbon efficiency. Herein, we construct a carbon efficiency model of solar-powered cellular networks using practical data from solar radiation. We propose a mechanism that alternately optimizes the performance of the renewable energy network and the cellular network. This approach is based on convex optimization theory and the Dinkelback algorithm, and it leads to the design of a carbon efficiency optimization algorithm. This algorithm aims to improve the carbon efficiency of cellular networks and reduce their carbon emissions. Simulation results demonstrate that our optimization scheme yields a maximum improvement of 2.56 × 108bps/g in the carbon efficiency of the cellular network as compared to conventional power allocation schemes such as the traditional water filling method and heuristic energy sharing and charge/discharge algorithms.

关键词： cellular networks renewable energy carbon efficiency convex optimization theory dinkelbach

Find truth in the hands of the few:acquiring specific knowledge with crowdsourcing

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Frontiers of Computer Science 2021年第4期15卷 5-16页

作者： tao han Hailong SUN Yangqiu SONG Yili FANG Xudong LIU SKLSDE Lab School of Computer Science and EngineeringBeihang UniversityBeijing 100191China Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang UniversityBeijing 100191China Department of Computer Science and Engineering Hong Kong University of Science and TechnologyClearwater BayHong Kong 999077China School of Computer and Information Engineering Zhejiang Gongshang UniversityHangzhou 310018China

Crowdsourcing has been a helpful mechanism to leverage human intelligence to acquire useful ***,when we aggregate the crowd knowledge based on the currently developed voting algorithms,it often results in common knowledge that may not be *** this paper,we consider the problem of collecting specific knowledge via *** the help of using external knowledge base such as WordNet,we incorporate the semantic relations between the alternative answers into a probabilisticmodel to determine which answer is more *** formulate the probabilistic model considering both worker’s ability and task’s difficulty from the basic assumption,and solve it by the expectation-maximization(EM)*** increase algorithm compatibility,we also refine our method into semi-supervised *** results show that our approach is robust with hyper-parameters and achieves better improvement thanmajority voting and other algorithms when more specific answers are expected,especially for sparse data.

关键词： crowdsourcing knowledge acquisition EM algorithm label aggregation