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Underwater square-root cubature attitude estimator by use of quaternion-vector switching and geomagnetic field tensor

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Journal of Systems Engineering and Electronics 2020年第4期31卷 804-814页

作者： HUANG Yu wu lihua YU Qiang Acoustic Science and Technology Laboratory Harbin Engineering UniversityHarbin 150001China Key Lab of In-fiber Integrated Optics Ministry Education of ChinaCollege of Physics and Optoelectronic EngineeringHarbin Engineering UniversityHarbin 150001China College of Automation Harbin Engineering UniversityHarbin 150001China

This paper presents a kind of attitude estimation algorithm based on quaternion-vector switching and square-root cubature Kalman filter for autonomous underwater vehicle(AUV).The filter formulation is based on geomagnetic field tensor measurement dependent on the attitude and a gyro-based model for attitude propagation. In this algorithm, switching between the quaternion and the three-component vector is done by a couple of the mathematical transformations. Quaternion is chosen as the state variable of attitude in the kinematics equation to time update, while the mean value and covariance of the quaternion are computed by the three-component vector to avoid the normalization constraint of quaternion. The square-root forms enjoy a continuous and improved numerical stability because all the resulting covariance matrices are guaranteed to stay positively semidefinite. The entire square-root cubature attitude estimation algorithm with quaternion-vector switching for the nonlinear equality constraint of quaternion is given. The numerical simulation of simultaneous swing motions in the three directions is performed to compare with the three kinds of filters and the results indicate that the proposed filter provides lower attitude estimation errors than the other two kinds of filters and a good convergence rate.

关键词： attitude estimator geomagnetic field tensor quaternion-vector switching square-root cubature Kalman filter autonomous underwater vehicle(AUV)

User Modeling for Personalized Recommender Systems

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Tsinghua Science and Technology 2005年第z1期10卷 772-777页

作者： LIU Lu wu lihua School of Economics and Management Beihang University Beijing 100083 China Department of Information Systems Beijing Information Science and Technology UniversityBeijing 100101 China

This paper models a user's interest and value related characteristics based on the extension by using neural networks and econometric techniques to the concept of user model in recommender systems. A two-dimensional taxonomy of user model was proposed in terms of the content and persistence of user characteristics. A user interest model and a customer lifetime value model were developed for the proposed taxonomy framework, to capture the time-dependent evolving nature of user's interests and his/her long-term profitability. The proposed models were empirically validated by using real customer data from a bee product company in health care industry. The experimental results show that these models provide effective assistant tools for the company to target its most valuable customers and implement one-to-one personalized services.

关键词： user interest model customer lifetime value (CLV) recommender systems customer relationship management (CRM) e-commerce

A self-adaptive correction method for perspective distortions of image

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Frontiers of Computer Science 2019年第3期13卷 588-598页

作者： lihua wu Qinghua SHANG Yupeng SUN Xu BAI School of Measurement and Communication Harbin University of Science and Technology Harbin 150080 China

Frequently, the shooting angles available to photograph an object are limited, and the resultant images contain perspective distortions. These distortions make more difficult to perform subsequent tasks like feature extraction and information identification. This paper suggested a perspective correction method that extracts automatically distortion features through edge detection. Results showed that this method is powerful in correcting images with perspective distortions. The corrected image has virtually little information missing, clear features and high recovery rate.

关键词： perspective correction perspective transformation Hough transform edge detection

A Dynamic Bandwidth Allocation Solution Based on User Behavior and Software Defined EPS

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China Communications 2016年第9期13卷 80-90页

作者： Bo Zhu Hao Jiang lihua wu Shuwen Yi Hai Wang School of Electronic Information Wuhan UniversityWuhan430072China Collaborative Innovation Center for Geospatial Technology Wuhan430079China

For telecommunication operators, how to improve the utilization of bandwidth resources is always a problem which worthy of study, nowadays, this issue has become more and more important, since the traffic load bursting in the mobile Internet. So the key to solving this problem is that we need to find a kind of traffic model to predict the traffic load that users need. According to the predicted traffic load to allocate bandwidth to each base station *** the traffic consumption behavior of a single base station is random, it is difficult to predict[ 1 ]. For this reason, we based on reality that, when the user moves, it may get traffic load from different base stations, therefore, there will have some kind of relationship between those base *** use this relationship to establish a kind of Spatial Collaborative ***, we make use of stability algorithm to divided those base station cluster into different communities, According to the traffic load usage rules which these communities indicated to us, we get a traffic *** the same time, we studied bow to use this traffic model in the future networks to dynamically allocate bandwidth resources, then we propose a new kind of EPS architecture based on SDN, on this platform, we can deploy our strategy through it＇s programmable ***, we designed an experiment to test the performance of our dynamic strategy, and the result shows that our method enables bandwidth utilization has been greatly improved.

关键词： bandwidth utilization user's behaviour traffic module SDN

Defect-mediated Rashba engineering for optimizing electrical transport in thermoelectric BiTeI

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npj Computational Materials 2020年第1期6卷 774-780页

作者： Xin Li Ye Sheng lihua wu Shunbo Hu Jiong Yang David J.Singh Jihui Yang Wenqing Zhang Materials Genome Institute Shanghai University99 Shangda Road200444 ShanghaiChina Materials Science and Engineering Department University of WashingtonSeattleWA 98195USA Department of Physics and Astronomy and Department of Chemistry University of MissouriColumbiaMO 65211USA Department of Physics and Shenzhen Institute for Quantum Science&Technology Southern University of Science and Technology518055 ShenzhenGuangdongChina Guangdong Provincial Key Laboratory of Computational Science and Material Design and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and Technology518055 ShenzhenGuangdongChina

The Rashba effect plays a vital role in electronic structures and related functional *** strength of the Rashba effect can be measured by the Rashba parameter α_(R);it is desirable to manipulate α_(R) to control the functional *** current work illustrates how α_(R) can be systematically tuned by doping,taking BiTeI as an example.

关键词： properties Rashba doping

An Experimental Study on Optimization of Large-volume Airgun Source Excitation Conditions in a Reservoir

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Earthquake Research in China 2016年第3期30卷 355-363页

作者： Chen Huifang Lin Binhua Jin Xing wu lihua Cai Huiteng Earthquake Administration of Fujian Province Fuzhou 350003 China Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China

Through manual pickup of seismic phases,the number of recording stations,the farthest observation distance of station and received energy are determined,then optimal operating condition processing software is developed to evaluate the excitation effect of operating conditions. The optimal operating conditions in the Mianhuatan Reservoir are determined using this software. They are: optimal water depth 25 m,airgun array sink depth 9m and airgun array size 7m × 7m. At the same time,accumulative stacking results for every 10 times are analyzed for 300 fixed-point excitations. It is concluded that the excitation effect shows a rapidly rising trend at 10 to 90 times stacking,a slowly rising trend at 100 to 150 times stacking,a rapidly rising trend at 160 to 240 times stacking,and a slowly rising trend at 250 to 300 times stacking. As the number of stacking increases,the propagation distance and the number of recording stations also increase gradually.

关键词： Optimum operating condition Stacking analysis Excitation effect Observation distance

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

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npj Computational Materials 2016年第1期2卷 216-232页

作者： Jiong Yang Lili Xi wujie Qiu lihua wu Xun Shi Lidong Chen Jihui Yang Wenqing Zhang Ctirad Uher David J Singh Materials Genome Institute Shanghai UniversityShanghaiChina State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghaiChina Department of Physics East China Normal UniversityShanghaiChina Material Science and Engineering Department University of WashingtonSeattleWAUSA Department of Physics University of MichiganAnn ArborMIUSA Department of Physics and Astronomy University of MissouriColumbiaMOUSA

During the last two decades,we have witnessed great progress in research on *** are two primary *** is the fundamental understanding of electrical and thermal transport,enabled by the interplay of theory and experiment;the other is the substantial enhancement of the performance of various thermoelectric materials,through synergistic optimisation of those intercorrelated transport *** we review some of the successful strategies for tuning electrical and thermal *** electrical transport,we start from the classical but still very active strategy of tuning band degeneracy(or band convergence),then discuss the engineering of carrier scattering,and finally address the concept of conduction channels and conductive networks that emerge in complex thermoelectric *** thermal transport,we summarise the approaches for studying thermal transport based on phonon–phonon interactions valid for conventional solids,as well as some quantitative efforts for *** also discuss the thermal transport in complex materials with chemical-bond hierarchy,in which a portion of the atoms(or subunits)are weakly bonded to the rest of the structure,leading to an intrinsic manifestation of part-crystalline part-liquid state at elevated *** this review,we provide a summary of achievements made in recent studies of thermoelectric transport properties,and demonstrate how they have led to improvements in thermoelectric performance by the integration of modern theory and experiment,and point out some challenges and possible directions.

关键词： electrical thermal theory

Dynamic evaluation of digital and green development policies based on text mining of the PMC framework

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Journal of Southeast University(English Edition) 2024年第3期40卷 319-326页

作者： Ye Chunmei wu lihua School of Economics and Management Southeast UniversityNanjing 211189China

Aiming to identify policy topics and their evolutionary logic that enhance the digital and green development(dual development)of traditional manufacturing enterprises,address weaknesses in current policies,and provide resources for refining dual development policies,a total of 15954 dual development-related policies issued by national and various departmental authorities in China from January 2000 to August 2023 were *** on topic modeling techniques and the policy modeling consistency(PMC)framework,the evolution of policy topics was visualized,and a dynamic assessment of the policies was *** results show that the digital and green development policy framework is progressively refined,and the governance philosophy shifts from a“regulatory government”paradigm to a“service-oriented government”.The support pattern evolves from“dispersed matching”to“integrated symbiosis”.However,there are still significant deficiencies in departmental cooperation,balanced measures,coordinated links,and multi-stakeholder *** policy improvements should,therefore,focus on guiding multi-stakeholder participation,enhancing public demand orientation,and addressing the entire value *** steps aim to create an open and shared digital industry ecosystem to promote the coordinated dual development of traditional manufacturing enterprises.

关键词： digital and green development text mining topic modeling policy modeling consistency(PMC)framework machine learning

Decentralized Safe Diagnosis of Fuzzy Discrete-Event Systems

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Decentralized Safe Diagnosis of Fuzzy Discrete-Event Systems