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High frequency S wave envelope synthesis using a multiple non-isotropic scattering model: application to aftershocks from the 2008 Wenchuan earthquake

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Earthquake Engineering and Engineering Vibration 2013年第2期12卷 185-194页

作者： lin Gao Jing Yueling li jianbo The State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Earthquake Engineering Research Division Dalian University of Technology

Based on the formulation of a multiple non-isotropic scattering process, a characteristic source time is introduced to define the initial impulse width of energy density at the source. An analytical expression of the initial intensity spectral density of a seismic wave is incorporated into the integral equation of seismic wave energy density. And, a recursive formula of Green＇s function is derived to obtain the higher order Green＇s function, which is included to describe the stronger non-isotropic scattering process. Then, the effect of the scattering pattern on the energy density envelope is investigated by the modified scattering theory. Significant differences arc found in the decay of the energy density envelopes with distances using different scattering patterns. The envelope synthesized by the forward dominated scattering pattern is larger than the results obtained by the isotropic and backward dominated scattering pattern. Different scattering patterns are also used to fit the observation data from the aftershocks of the 2008 Wenchuan earthquake. It is concluded that the envelopes synthesized by the forward scattering pattern can match the data better than the isotropic and backward dominated scattering cases, and a new interpretation of the coda wave is given. Finally, using the forward dominated scattering pattern, the envelope broadening of the observed data is reproduced.

关键词： non-isotropic scattering coda wave envelope broadening energy transport theory (radiative transfer theory) directional scattering coefficient ground motion

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Dynamic interaction numerical models in the time domain based on the high performance scaled boundary finite element method

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Earthquake Engineering and Engineering Vibration 2013年第4期12卷 541-546页

作者： li jianbo liu Jun lin Gao The State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Institute of Earthquake Engineering School of Hydraulic EngineeringDalian University of Technology

Consideration of structure-foundation-soil dynamic interaction is a basic requirement in the evaluation of the seismic safety of nuclear power facilities. An efficient and accurate dynamic interaction numerical model in the time domain has become an important topic of current research. In this study, the scaled boundary finite element method （SBFEM） is improved for use as an effective numerical approach with good application prospects. This method has several advantages, including dimensionality reduction, accuracy of the radial analytical solution, and unlike other boundary element methods, it does not require a fundamental solution. This study focuses on establishing a high performance scaled boundary finite element interaction analysis model in the time domain based on the acceleration unit-impulse response matrix, in which several new solution techniques, such as a dimensionless method to solve the interaction force, are applied to improve the numerical stability of the actual soil parameters and reduce the amount of calculation. Finally, the feasibility of the time domain methods are illustrated by the response of the nuclear power structure and the accuracy of the algorithms are dynamically verified by comparison with the refinement of a large-scale viscoelastic soil model.

关键词： time domain analysis dynamic interaction acceleration impulse response function scaled boundary finiteelement method viscoelastic boundary

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Predicting Human Mobility via Long Short-Term Patterns

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Computer Modeling in Engineering & Sciences 2020年第9期124卷 847-864页

作者： Jianwei Chen jianbo li Ying li College of Computer Science and Technology Qingdao UniversityQingdao266071China

Predicting human mobility has great significance in Location based Social Network applications,while it is challenging due to the impact of historical mobility patterns and current *** these challenges,historical patterns tend to be crucial in the prediction ***,it is difficult to capture complex patterns from long historical *** by recent success of Convolutional Neural Network(CNN)-based methods,we propose a Union ConvGRU(UCG)Net,which can capture long short-term patterns of historical trajectories and sequential impact of current ***,we first incorporate historical trajectories into hidden states by a shared-weight layer,and then utilize a 1D CNN to capture short-term pattern of hidden ***,an average pooling method is involved to generate separated hidden states of historical trajectories,on which we use a Fully Connected(FC)layer to capture longterm pattern ***,we use a Recurrent Neural Net-work(RNN)to predict future trajectories by integrating current trajectories and long short-term *** demonstrate that UCG Net performs best in comparison with neural network-based methods.

关键词： Human mobility prediction CNN average pooling

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Research on the attribution evaluating methods of dynamic effects of various parameter uncertainties on the in-structure floor response spectra of nuclear power plant

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Earthquake Engineering and Engineering Vibration 2017年第1期16卷 47-54页

作者： li jianbo lin Gao liu Jun li Zhiyuan State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China Ocean Engineering Joint Research Center of D UT- UWA Dalian University of Technology Dalian 116024 China

： Consideration of the dynamic effects of the site and structural parameter uncertainty is required by the standards for nuclear power plants （NPPs） in most countries. The anti-seismic standards provide two basic methods to analyze parameter uncertainty. Directly manually dealing with the calculated floor response spectra （FRS） values of deterministic approaches is the first method. The second method is to perform probability statistical analysis of the FRS results on the basis of the Monte Carlo method. The two methods can only reflect the overall effects of the uncertain parameters, and the results cannot be screened for a certain parameter＇s influence and contribution. In this study, based on the dynamic analyses of the floor response spectra of NPPs, a comprehensive index of the assessed impact for various uncertain parameters is presented and recommended, including the correlation coefficient, the regression slope coefficient and Tornado swing. To compensate for the lack of guidance in the NPP seismic standards, the proposed method can effectively be used to evaluate the contributions of various parameters from the aspects ＆sensitivity, acuity and statistical swing correlations. Finally, examples are provided to verify the set of indicators from systematic and intuitive perspectives, such as the uncertainty of the impact of the structure parameters and the contribution to the FRS of NPPs. The index is sensitive to different types of parameters, which provides a new technique for evaluating the anti-seismic parameters required for NPPs.

关键词： uncertain parameter floor response spectra (FRS) soil-structure interaction (SSI) seismic analysis andstructural design nuclear power plant (NPP)

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Flight dynamics modeling and analysis for a Mars helicopter

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Chinese Journal of Aeronautics 2023年第9期36卷 221-230页

作者： Hong ZHAO Zhiwei DING Gen LENG jianbo li National Key Laboratory of Helicopter Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Helicopter Research&Development Institute Jingdezhen 33300China

Flight dynamics modeling for the Mars helicopter faces great *** modeling of coaxial rotor with high confidence and high computational efficiency is a major difficulty for the *** paper builds an aerodynamic model of coaxial rotor in the extremely thin Martian atmosphere using the viscous vortex particle *** aerodynamic forces and flow characteristics of rigid coaxial rotor are computed and ***,a high fidelity aerodynamic surrogate model is built to improve the computational efficiency of the flight dynamics *** in this paper reveal that rigid coaxial rotor can bring the Mars helicopter sufficient controllability but result in obvious instability and control couplings in forward *** highlights the great differences in flight dynamics characteristics compared with conventional helicopters on Earth.

关键词： Aerodynamic modeling Coaxial rotor Flight dynamics Mars helicopter Viscous Vortex Particle Method(VVPM)

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Strain and kinematic vorticity analysis of the Louzidian low-angle ductile shear detachment zone in Chifeng,Inner Mongolia,China

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Science China Earth Sciences 2010年第11期53卷 1611-1624页

作者： li jianbo WANG Tao OUYANG ZhiXia Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China East China Institute of Technology Fuzhou 344000China

The Louzidian low-angle ductile shear detachment zone at the south of Chifeng is a SE-dipping, low-angle normal fault system. It is composed mainly of ductile shear zone, ductile-brittle shear zone and brittle fault zone. The ductile shear zone consists of, from bottom to top, mylonitic rocks, protomylonites and mylonites. Finite strain measurement of feldspar strain markers from those rocks using the Rf /φ method shows that strain intensities (Es) of the mylonite at core of the ductile shear zone (Es=0.65-0.96) are higher than those of the mylonitic rocks close to the granite intrusions (Es=0.59-0.62) and of the protomylonites at top of the ductile shear zone (Es= 0.47-0.70), and the strain types of the protomylonites and mylonties are elongate strain and plane-flattening strain, respectively. The kinematic vorticity values (Wk) estimated by the Polar Mohr diagram and the Rigid Grain Net range from 0.81 to 0.90 with an average of 0.85 for the protomylonites, and from 0.53 to 0.80 with 0.66 on average for the mylonites; Wk values of the extensional crenulation cleavage, i.e., C′, estimated by C′ method range from 0.63 to 0.37 with an average of 0.50. The angles between the maximum principal stress and shearing direction determined using the Maximum effective moment criterion evolved from 61° to 69° and to 75°, and finally normal to shearing direction. The results of strain and kinematic vorticity measurements suggest that high strain corresponds to low kinematic vorticity. Kinematic vorticity measurements show that the Louzidian low-angle ductile shear detachment zone is a result of a combination of simple-dominated general shearing at the early stage and pure-dominated general shearing at the late stage. All these, together with isotope geochronology and regional tectonic background, suggest that the Louzidian ductile shear detachment zone resulted from a combination of crust extension and magma intrusion. The model of simple shear at the early stage and pure shear

关键词： Louzidian low-angle ductile shear detachment zone mylonite strain intensity kinematic vorticity principal stress

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Hierarchical Carbon Microtube@Nanotube Core-Shell Structure for High-Performance Oxygen Electrocatalysis and Zn-Air Battery

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Nano-Micro Letters 2020年第8期12卷 46-59页

作者： Wenfu Xie Jianming li Yuke Song Shijin li jianbo li Mingfei Shao State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China Petroleum Geology Research and Laboratory Center Research Institute of Petroleum Exploration and Development(RIPED)PetroChinaBeijing 100083People’s Republic of China

Zinc-air batteries(ZABs)hold tremendous promise for clean and efficient energy storage with the merits of high theoretical energy density and environmental ***,the performance of practical ZABs is still unsatisfactory because of the inevitably decreased activity of electrocatalysts when assembly into a thick electrode with high mass ***,we report a hierarchical electrocatalyst based on carbon microtube@nanotube core-shell nanostructure(CMT@CNT),which demonstrates superior electrocatalytic activity for oxygen reduction reaction and oxygen evolution reaction with a small potential gap of 0.678 ***,when being employed as air-cathode in ZAB,the CMT@CNT presents an excellent performance with a high power density(160.6 mW cm^−2),specific capacity(781.7 mAhgZn^−1)as well as long cycle stability(117 h,351 cycles).Moreover,the ZAB performance of CMT@CNT is maintained well even under high mass loading(3 mg cm−2,three times as much as traditional usage),which could afford high power density and energy density for advanced electronic *** believe that this work is promising for the rational design of hierarchical structured electrocatalysts for advanced metal-air batteries.

关键词： Hierarchical structure Carbon microtube@nanotube Core–shell Zinc–air battery

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Seed Selection for Data Offloading Based on Social and Interest Graphs

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Computers, Materials & Continua 2018年第12期57卷 571-587页

作者： Ying li jianbo li Jianwei Chen Minchao Lu Caoyuan li College of Computer Science and Technology Qingdao UniversityQingdao266071China School of Computer Beijing Institute of TechnologyBeijing100081China Faculty of Engineering and Information Technology University of Technology SydneyNSW 2006Australia

The explosive growth of mobile data demand is becoming an increasing burden on current cellular *** address this issue,we propose a solution of opportunistic data offloading for alleviating overloaded cellular *** principle behind it is to select a few important users as seeds for data *** three critical steps are detailed as *** first explore individual interests of users by the construction of user profiles,on which an interest graph is built by Gaussian graphical *** then apply the extreme value theory to threshold the encounter duration of user ***,a contact graph is generated to indicate the social relationships of ***,a contact-interest graph is developed on the basis of the social ties and individual interests of *** on different graphs,three strategies are finally proposed for seed selection in an aim to maximize overloaded cellular *** evaluate the performance of our algorithms by the trace data of real-word *** demonstrates the effectiveness of the strategy of taking social relationships and individual interests into account.

关键词： Mobile social network social data offloading extreme value model Gaussian graphical model

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The Early Mesozoic NE-SW Extensional Model and Exhumation Processes at the Southeastern Margin of the Central Asian Orogenic Belt:Insights from the Strain and Kinematic Vorticity Analysis of the Sonid Zuoqi Ductile Detachment Zone

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1141-1153页

作者： li jianbo SONG Zhijie LEI Hengcong ZENG Tao East China University of Technology Nanchang 344000China

The Sonid Zuoqi ductile detachment zone is located at the southeastern margin of the Central Asian orogenic belt(CAOB),striking EW and dipping to the *** major rock type of the Sonid Zuoqi ductile detachment zone is mylonite derived from *** sequence of mylonite features is:(1)S and C foliations of mylonite,and(2)extensional crenulation cleavage(ecc)or C′and the kinematic vorticity(Wk)value changed from 0.70 to 0.95 and from 0.37 to 0.69,respectively;the strain type of the mylonites within the Sonid Zuoqi ductile detachment zone is compressional to planar *** strong deformation mylonite and Halatu plutons yielded a zircon U-Pb age of 244 Ma and a zircon(U-Th)/He age of 214 Ma,*** on the strain and kinematic vorticity analysis,together with the zircon U-Pb and zircon(U-Th)/He ages and the regional tectonic background,the study area experienced three stage evolution:tangential simpleshear(244 Ma),simple-shear-dominated general shear represented by upper crustal extension(224 Ma)and pure-shear-dominated general shear represented by the Halatu pluton doming(214 Ma),which constrained the early Mesozoic NE-SW crustal extension at the southeastern margin of the *** NE-SW extension probably originated from the postorogenic extensional collapse of the CAOB,subsequent exhumation being controlled by the far afield effects of the closure of the Mongol-Okhotsk belt.

关键词： strain simple shear pure shear kinematic vorticity ductile detachment zone

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Collaborative City Digital Twin for the COVID-19 Pandemic:A Federated Learning Solution

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Tsinghua Science and Technology 2021年第5期26卷 759-771页

作者： Junjie Pang Yan Huang Zhenzhen Xie jianbo li Zhipeng Cai the College of Computer Science and Technology Qingdao UniversityQingdao 266000China the Business School Qingdao UniversityQingdao 266000China the College of Computing and Software Engineering Kennesaw State UniversityAtlantaGA 30060USA the College of Computer Science and Technology Jilin UniversityChangchun 130012China the Department of Computer Science Georgia State UniversityAtlantaGA 30303USA

The novel coronavirus,COVID-19,has caused a crisis that affects all segments of the *** the knowledge and understanding of COVID-19 evolve,an appropriate response plan for this pandemic is considered one of the most effective methods for controlling the spread of the *** studies indicate that a city Digital Twin(DT)is beneficial for tackling this health crisis,because it can construct a virtual replica to simulate factors,such as climate conditions,response policies,and people's trajectories,to help plan efficient and inclusive ***,a city DTsystem relies on long-term and high-quality data collection to make appropriate decisions,limiting its advantages when facing urgent crises,such as the COVID-19 *** Learning(FL),in which all clients can learn a shared model while retaining all training data locally,emerges as a promising solution for accumulating the insights from multiple data sources ***,the enhanced privacy protection settings removing the privacy barriers lie in this *** this work,we propose a framework that fused city DT with FL to achieve a novel collaborative paradigm that allows multiple city DTs to share the local strategy and status *** particular,an FL central server manages the local updates of multiple collaborators(city DTs),providing a global model that is trained in multiple iterations at different city DT systems until the model gains the correlations between various response plans and infection *** approach means a collaborative city DT paradigm fused with FL techniques can obtain knowledge and patterns from multiple DTs and eventually establish a"global view"of city crisis ***,it also helps improve each city's DT by consolidating other DT's data without violating privacy *** this paper,we use the COVID-19 pandemic as the use case of the proposed *** experimental results on a real dataset with various response plans val

关键词： COVID-19 Digital Twin(DT) Federated Learning(FL) deep learning

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