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Source localization and calibration using TDOA and FDOA measurements in the presence of sensor location uncertainty

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Science China(Information Sciences) 2014年第4期57卷 156-167页

作者： LI JinZhou guo fucheng JIANG WenLi School of Electronics Science and Engineering National University of Defense Technology

Source localization accuracy is very sensitive to sensor location *** paper performs analysis and develops a solution for locating a moving source using time difference of arrival(TDOA)and frequency difference of arrival(FDOA)measurements with the use of a calibration *** a Gaussian random signal model,we first derive the Cram′er-Rao lower bound(CRLB)for source location estimate in this *** we analyze the differential calibration technique which is commonly used in Global Positioning *** is indicated that the differential calibration cannot attain the CRLB accuracy in most cases.A closed-form solution is then proposed which takes a calibration emitter into account to reduce sensor location *** is shown analytically that under some mild approximations,our approach is able to reach the CRLB *** simulations are included to corroborate the theoretical developments.

关键词： source localization calibration time difference of arrival(TDOA) frequency difference of arrival(FDOA) sensor location uncertainty Cram′er-Rao lower bound(CRLB)

Translocation and biotoxicity of metal (oxide) nanoparticles in the wetland-plant system

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Frontiers of Environmental Science & Engineering 2021年第6期15卷 471-483页

作者： Xiangyu Yang Qiang He fucheng guo Xiaobo Liu Yi Chen Key Laboratory of the Three Gorges Region’s Eco-Environment(Ministry of Education) College of Environment and EcologyChongqing UniversityChongqing 400044China National Centre for International Research of Low-Carbon and Green Buildings Chongqing UniversityChongqing 400044China

Engineered nanoparticles(ENPs)threaten the environment through wastewater ***,constructed wetlands(CWs)are efficient methods for ENPs ***,the biotoxicity of ENPs on plants in CWs is ***,we investigated the distribution and bio-impacts of different ENPs(Ag NPs,TiO_(2) NPs,and CeO_(2) NPs)in plants under 5-and 60-day exposure to 1 and 50 mg/L *** showed that ENPs appeared in the vascular bundle and mesophyll cell space,which induced the variation in antioxidase activities(e.g.,superoxide dismutase[SOD],peroxidase[POD],and catalase[CAT]activities)as well as overproduction of malondialdehyde(MDA).Additionally,Ag NPs inhibited photosynthesis rate and root activity during two exposure ***_(2) NPs had positive and negative impacts on plants in 5-and 60-day exposure,***,TiO_(2) NPs enhanced photosynthesis and root activity under 60-day ***,the contents of the C,N,and P elements in plants fluctuated in response to ENPs *** results have a positive correlation with the wetland performance under ENPs exposure except for TiO_(2) NPs ***,our study systematically reveals aquatic plants'responses to ENPs and provides a reference for building ecological treatment systems to purify wastewater containing ENPs.

关键词： Constructed wetlands Aquatic plants Nanoparticles Physiological activity Biomass

Solving Geometry Problems via Feature Learning and Contrastive Learning of Multimodal Data

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Computer Modeling in Engineering & Sciences 2023年第8期136卷 1707-1728页

作者： Pengpeng Jian fucheng guo Yanli Wang Yang Li North China University of Water Resources and Electric Power Zhengzhou450046China Henan University of Economics and Law Zhengzhou450046China

This paper presents an end-to-end deep learning method to solve geometry problems via feature learning and contrastive learning of multimodal data.A key challenge in solving geometry problems using deep learning is to automatically adapt to the task of understanding single-modal and multimodal *** methods either focus on single-modal ormultimodal problems,and they cannot fit each other.A general geometry problem solver shouldobviouslybe able toprocess variousmodalproblems at the same ***,a shared feature-learning model of multimodal data is adopted to learn the unified feature representation of text and image,which can solve the heterogeneity issue between multimodal geometry problems.A contrastive learning model of multimodal data enhances the semantic relevance betweenmultimodal features and maps them into a unified semantic space,which can effectively adapt to both single-modal and multimodal downstream *** on the feature extraction and fusion of multimodal data,a proposed geometry problem solver uses relation extraction,theorem reasoning,and problem solving to present solutions in a readable *** results show the effectiveness of the method.

关键词： Geometry problems multimodal feature learning multimodal contrastive learning automatic solver

A new iterative algorithm for geolocating a known altitude target using TDOA and FDOA measurements in the presence of satellite location uncertainty

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Chinese Journal of Aeronautics 2015年第5期28卷 1510-1518页

作者： Cao Yalu Peng Li Li Jinzhou Yang Le guo fucheng School of Internet of Things (Io T) Engineering Jiangnan University College of Electronic Science and Engineering National University of Defense Technology Synergetic Innovation Center of Food Safety and Nutrition

This paper considers the problem of geolocating a target on the Earth surface whose altitude is known previously using the target signal time difference of arrival （TDOA） and frequency difference of arrival （FDOA） measurements obtained at satellites. The number of satellites available for the geolocation task is more than sufficient and their locations are subject to random errors. This paper derives the constrained Cramor-Rao lower bound （CCRLB） of the target position, and on the basis of the CCRLB analysis, an approximately efficient constrained maximum likelihood estimator （CMLE） for geolocating the target is established. A new iterative algorithm for solving the CMLE is then proposed, where the updated target position estimate is shown to be the globally optimal solution to a generalized trust region sub-problem （GTRS） which can be found via a simple bisection search. First-order mean square error （MSE） analysis is conducted to quantify the performance degradation when the known target altitude is assumed to be precise but indeed has an unknown but deterministic error. Computer simulations are used to compare the performance of the proposed iterative geolocation technique with those of two benchmark algorithms. They verify the approximate efficiency of the proposed algorithm and the validity of the MSE analysis.

关键词： Constrained Cram6r-Raolower bound (CCRLB):Frequency difference ofarrival (FDOA) Generalized trust regionsub-problem (GTRS):Performance analysis:Time difference of arrival(TDOA)

Reversible self-assembly of gold nanorods mediated by photoswitchable molecular adsorption

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Nano Research 2019年第7期12卷 1563-1569页

作者： Qian Wang Di Li Junyan Xiao fucheng guo Limin Qi Beijing National Laboratory for Molecular Sciences (BNLMS) College of ChemistryPeking UniversityBeijing 100871China

Stimuli-responsive self-assembly of nanoparticles represents a powerful strategy to achieve reconfigurable materials with novel functionalities and promising *** this regard,light-induced reversible self-assembly (LIRSA) of nanoparticles is most attractive but it is usually limited by the prerequisite yet cumbersome chemical functionalizations of the particle *** we describe an innovative method to realize LIRSA of gold nanorods (GNRs) without surface functionalization through photoswitchable adsorption of an anionic azobenzene derivate *** LIRSA of GNRs is caused by the reversible change between a nearly neutral state and a highly charged state of the GNRs arising from the photoswichable adsorption of AzoNa triggered by *** LIRSA behavior can be readily adjusted by changing the concentration of AzoNa and the aspect ratio of the *** new LIRSA strategy may provide a convenient and efficient route toward light-triggered reversibly reconfigurable nanomaterials.

关键词： self-assembly of nanoparticles gold nanorods reversible self-assembly photoswichable adsorption reconfigurable nanomaterials

Evaluation of the compatibility between rubber and asphalt based on molecular dynamics simulation

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Frontiers of Structural and Civil Engineering 2020年第2期14卷 435-445页

作者： fucheng guo Jiupeng ZHANG Jianzhong PEI Weisi MA Zhuang HU Yongsheng GUAN Key Laboratory for Special Area Highway Engineering of Ministry of Education Chang'an UniversityXi'an 710064China Jiangsu Sinoroad Engineering Research Institute Co. LtdNanjing 211806China

Using of rubber asphalt can both promote the recycling of waste tires and improve the performance of asphalt ***,the segregation of rubber asphalt caused by the poor storage stability always appears during its *** stability of asphalt and rubber is related to the compatibility and also influenced by rubber *** this study,molecular models of different rubbers and chemical fractions of asphalt were built to perform the molecular dynamics *** solubility parameter and binding energy between rubber and asphalt were obtained to evaluate the compatibility between rubber and asphalt as well as the influence of rubber content on *** show that all three kinds of rubber are commendably compatible with asphalt,where the compatibility between asphalt and cis-polybutadiene rubber(BR)is the best,followed by styrene-butadiene rubber(SBR),and natural rubber(NR)is the *** optimum rubber contents for BR asphalt,SBR asphalt,and NR asphalt were determined as 15%,15%,and 20%,*** addition,the upper limits of rubber contents were found as between 25%and 30%,between 20%and 25%,and between 25%and 30%,respectively.

关键词： rubber asphalt compatibility rubber content molecular dynamics simulation

Effect of wetland plant fermentation broth on nitrogen removal and bioenergy generation in constructed wetland-microbial fuel cells

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Frontiers of Environmental Science & Engineering 2022年第12期16卷 89-100页

作者： Yiting Chen Jun Yan Mengli Chen fucheng guo Tao Liu Yi Chen Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment(Ministry of Education) Chongqing UniversityChongqing400045China College of Environment and Ecology Chongqing UniversityChongqing400045China

Constructed wetlands(CWs)are widely used as a tertiary treatment technology,and the addition of carbon sources can significantly improve advanced nitrogen ***,excessive carbon sources would lead to an increase in the effluent chemical oxygen demand in CWs,and microbial fuel cells(MFCs)can convert these into *** this study,constructed wetland-microbial fuel cells(CW-MFCs)were built to achieve simultaneous nitrogen removal and electricity generation,using wetland plant litter fermentation broths as carbon *** total nitrogen removal in the groups with fermentation broth addition(FGs)reached 83.33%,which was 19.64%higher than that in the CG(group without fermentation broth),and the mean voltages in the FGs were at least 2.6 times higher than that of the ***,two main components of the fermentation broths,acetic acid(Ac)and humic acid(HA),were identified using a three-dimensional excitation emission matrix and gas chromatograph and added to CW-MFCs to explore the influence mechanism on the treatment *** and electrogenesis presented the same tendency:Ac&HA>Ac>CG’(groups without Ac and HA).These results indicate that Ac and HA increased the abundance of functional genes associated with nitrogen metabolism and electron *** study demonstrated that CW-MFC fermentation broth addition can be a potential strategy for the disposal of secondary effluent and bioelectricity generation.

关键词： Constructed wetland Microbial fuel cell Nitrogen removal Bioenergy generation Carbon source

Utilization of Modified Spherical Coordinates for Satellite to Satellite Bearings-Only Tracking

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空间科学学报 2009年第6期29卷 627-634页

作者： LI Qiang SHI Lihui WANG Hongxian guo fucheng 63961 Unit People＇s Liberation Army Beijing 100012 School of Electronic Science and Engineering National University of Defense Technology

A new satellite to satellite passive tracking method using Bearings-Only measurements in Modified Spherical Coordinates(MSC) is *** system dynamics and measurement process are presented in three-dimensional MSC,and then the tracking method is deduced in details based on the Cartesian *** of the new method is validated through computer simulations,which proved that the proposed method is effective in terms of the estimation accuracy and convergence time compared with the Cartesian method no matter the Initial State Errors(ISE) and measurement errors are large or small.

关键词：航天器飞行力学 MSC 侦察特殊问题

A new satellite to satellite tracking algorithm from Doppler-shifted frequency measurements

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Progress in Natural Science:Materials International 2007年第10期17卷 1226-1234页

作者： Li Qiang, guo fucheng and Zhou Yiyu(School of Electronic Science & Engineering, National University of Defense Technology, Changsha 410073, China) School of Electronic Science & Engineering National University of Defense Technology Changsha 410073 China

A new satellite to satellite tracking (SST) algorithm from Doppler-shifted frequency measurements is proposed. The estimation principle is demonstrated and the mathematic model of SST is established. The state estimation methods for a user (the cooperative case) and target satellites (the non-cooperative case) are presented based on particle swarm optimization (PSO). The Cramer-Rao lower bounds (CRLB) are deduced as well. Performance of the new algorithm is validated through computer simulations, which proved that the proposed method is effective in terms of the estimation quality compared with CRLB and superior in accuracy to the Bearings-Only (BO) method in almost all simulation cases except for the case that an enough long tracking arc-length is obtained for a user satellite.

关键词： satellite to satellite tracking (SST) Doppler-shifted frequency (DSF) Space Surveillance Network (SSN) particle swarm optimization (PSO).