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Maneuvering Target Tracking in Dense Clutter Based on Particle Filtering

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Chinese Journal of Aeronautics 2011年第2期24卷 171-180页

作者： yang xiaojun XING Keyi FENG Xingle School of Information Engineering Chang'an University Xi'an 710064 China The National Key Laboratory for Manufacturing System Engineering Xi 'an Jiaotong University Xi'an 710049 China

An improved particle filtering（IPF） is presented to perform maneuvering target tracking in dense *** proposed filter uses several efficient variance reduction methods to combat particle degeneracy,low mode prior probabilities and measure-ment-origin *** the framework of a hybrid state estimation,each particle samples a discrete mode from its poste-rior distribution and the continuous state variables are approximated by a multivariate Gaussian mixture that is updated by an unscented Kalman filtering（UKF）.The uncertainty of measurement origin is solved by Monte Carlo probabilistic data associa-tion method where the distribution of interest is approximated by particle filtering and *** data association and precise behavior mode detection are successfully achieved by the proposed method in the environment with heavy clutter and very low mode prior *** performance of the proposed filter is examined and compared by Monte Carlo simulation over typical target scenario for various clutter *** simulation results show the effectiveness of the proposed filter.

关键词： particle filtering Monte Carlo methods Kalman filter probability data association target tracking nonlinear filtering

Review on the adhesive tendrils of Parthenocissus

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Chinese Science Bulletin 2014年第2期59卷 113-124页

作者： xiaojun yang Wenli Deng College of Materials Science and Engineering South China University of Technology

320 years ago,the adhesive tendrils of Parthenocissus were ***,the permanent attachment system of the tendrils is retrieved *** microscopy,scanning electron microscopy and transmission electron microscopy observations provide sufficient information on the characteristic attachment ***,cytochemical and immunocytochemical methods unravel the sorts and the molecular compositions of the secreted adhesive *** review provides a general overview of the whole research history and the latest progress in this *** authors elaborate the adhesive tendrils of Parthenocissus from macroscopic morphology,through microscopic structure,secreted adhesive fluid,adhesive force and adhesion mechanism to bionic exploration and application.

关键词：爬山虎胶粘剂卷须电子显微镜观察扫描电子显微镜粘性液体微观结构光学显微镜

Review on ultra-lightweight flapping-wing nano air vehicles:Artificial muscles,flight control mechanism,and biomimetic wings

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Chinese Journal of Aeronautics 2023年第6期36卷 63-91页

作者： Liang WANG Bifeng SONG Zhongchao SUN xiaojun yang School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China yangtze River Delta Research Institute Northwestern Polytechnical UniversityTaicang 215400China

Flying insects are capable of flapping their wings to provide the required power and control forces for flight.A coordinated organizational system including muscles,wings,and control architecture plays a significant role,which provides the sources of inspiration for designing flapping-wing *** recent years,due to the development of micro-and meso-scale manufacturing technologies,advances in components technologies have directly led to a progress of smaller Flapping-Wing Nano Air Vehicles(FWNAVs)around gram and sub-gram scales,and these air vehicles have gradually acquired insect-like locomotive strategies and *** paper will present a selective review of components technologies for ultra-lightweight flapping-wing nano air vehicles under 3 g,which covers the novel propulsion methods such as artificial muscles,flight control mechanisms,and the design paradigms of the insect-inspired wings,with a special focus on the development of the driving technologies based on artificial muscles and the progress of the biomimetic *** challenges involved in constructing such small flapping-wing air vehicles and recommendations for several possible future directions in terms of component technology enhancements and overall vehicle performance are also discussed in this *** review will provide the essential guidelines and the insights for designing a flapping-wing nano air vehicle with higher performance.

关键词： Actuators Artificial muscle Biomimetic wings Flapping wing Flight control mechanism Nano Air Vehicles(NAVs)

A Brief Review on Aerodynamic Performance of Wingtip Slots and Research Prospect

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Journal of Bionic Engineering 2021年第6期18卷 1255-1279页

作者： Dan Liu Bifeng Song Wenqing yang xiaojun yang Dong Xue Xinyu Lang School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang215400China

Wingtip slots,where the outer primary feathers of birds split and spread vertically,are regarded as an evolved favorable feature that could effectively improve their aerodynamic *** have inspired many to perform experiments and simulations as well as to relate their results to aircraft *** paper aims to provide guidance for the research on the aerodynamic mechanism of wingtip *** a review of previous wingtip slot research,four imperfections are put forward:vacancies in research content,inconsistencies in research conclusions,limitations of early research methods,and shortage of the aerodynamic mechanism *** this basis,further explorations and expansion of the influence factors for steady state are needed;more attention should be poured into the application of flow field integration method to decompose drag,and evaluation of variation in induced drag seems a more rational *** and kinematic parameters of wingtip slot structure in the unsteady state,as well as the flexibility of wingtips,should be taken into *** for the aerodynamic mechanism of wingtip slots,the emphasis can be placed on the study of the formation,development,and evolution of wingtip vortices on slotted ***,some research strategies and feasibility analyses are proposed for each part of the research.

关键词： Slotted wingtip Tip vortex Drag reduction Unsteady state Flexibility

Impact of essential oils and organic acids on the growth performance,digestive functions and immunity of broiler chickens

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Animal Nutrition 2018年第4期4卷 388-393页

作者： Xin yang Hongliang Xin Chengbo yang xiaojun yang College of Animal Science and Technology Northwest A&F UniversityYangling712100China Jefo Nutrition Inc. Saint-HyacintheQuebecJ2S 7B6Canada

The aim of the experiment was to study the effects of feeding blends of sorbic acid, fumaric acid, and thymol(EOA) on growth performance, digestive functions, and immunity of broiler chickens. A total of 640 one-day-old male Cobb 500 chicks with similar BW(41.8 ± 0.6 g) were randomly divided into 4dietary treatment groups consisting of 10 replicates with 16 birds per replicate and fed a basal diet until d 42(CON) or diets with 0.15 g/kg enramycin during the grower period(AG), 0.30 g/kg EOA during the grower period(EG), or 0.30 g/kg EOA during the finisher period(EF). At d 42, the feed conversion ratio was reduced(P < 0.05) for birds in EG group compared with other groups. Birds in EG group showed a higher villus height of the duodenum and jejunum and muscular layers of the duodenum and ileum than birds in CON group(P < 0.05). Compared with other groups, crypt depth of the jejunum and ileum was markedly increased(P < 0.05) by EOA supplementation during the finisher period at d 42. The EOA supplementation during grower period increased significantly lipase, trypsin and chymotrypsin activities of the duodenum at d 21 and 42, as well as lipase and trypsin at d 21, and trypsin and chymotrypsin at d 42 in the jejunum, and trypsin and chymotrypsin activities of the ileum at d 21 compared to the control diet(P < 0.05). Birds of EG and EF groups showed a higher(P < 0.05) spleen index than birds of CON group. The level of secretory immunoglobulin A in duodenal and ileal mucosa was increased(P < 0.05) in EF group at d 42 compared with other groups. In conclusion, the results indicate that EOA can be effectively applied in broiler diets, especially during the grower phase by improving intestinal morphology and increasing digestive enzyme activity.

关键词： Broiler chicken Digestive functions Essential oils Growth performance Immunity Organic acids

Ultrasonic Nondestructive Signals Processing Based on Matching Pursuit with Gabor Dictionary

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Chinese Journal of Mechanical Engineering 2011年第4期24卷 591-595页

作者： GUO Jinku WU Jinying yang xiaojun LIU Guangbin Xi＇an Research Institute of High Technology Hongqing Town Xi＇an 710025 China Department of Automation Tsinghua University Beijing 100084 China

The success of ultrasonic nondestructive testing technology depends not only on the generation and measurement of the desired waveform, but also on the signal processing of the measured waves. The traditional time-domain methods have been partly successful in identifying small cracks, but not so successful in estimating crack size, especially in strong backscattering noise. Sparse signal representation can provide sparse information that represents the signal time-frequency signature, which can also be used in processing ultrasonic nondestructive signals. A novel ultrasonic nondestructive signal processing algorithm based on signal sparse representation is proposed. In order to suppress noise, matching pursuit algorithm with Gabor dictionary is selected as the signal decomposition method. Precise echoes information, such as crack location and size, can be estimated by quantitative analysis with Gabor atom. To verify the performance, the proposed algorithm is applied to computer simulation signal and experimental ultrasonic signals which represent multiple backscattered echoes from a thin metal plate with artificial holes. The results show that this algorithm not only has an excellent performance even when dealing with signals in the presence of strong noise, but also is successful in estimating crack location and size. Moreover, the algorithm can be applied to data compression of ultrasonic nondestructive signal.

关键词： ultrasonic signal processing sparse representation matching pursuit Gabor dictionary

Age-associated changes in caecal microbiome and their apparent correlations with growth performances of layer pullets

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Animal Nutrition 2021年第3期7卷 841-848页

作者： Yanli Liu Tao Yan Zhouzheng Ren xiaojun yang College of Animal Science and Technology Northwest A&F UniversityYangling 712100China

The microbiome in gastrointestinal tracts play an important role in regulating nutrient utilization and absorption, gut immune function, and host growth or development. This study was conducted to investigate the composition and dynamic distribution of caecal microbiota in pullets during the first 16 weeks. Growth performance, immune organs index, and intestinal morphology of pullets were analyzed at 3, 6, 12 and 16 weeks of age. The caecal contents were collected for microbiota analysis by 16S rRNA gene sequencing method. With advancing ages in pullets, the gradually increased average daily feed intake (ADFI), feed conversion ratio (FCR) and intestinal villus height, but the gradually decreased organs index of thymus and bursa were determined. Meanwhile, more abundant caecal bacterial com-munities were determined from pullets at 12 and 16 weeks of age than those at 3 and 6 weeks of age. Furthermore, the dominant microflora of pullets from different weeks of age were analyzed by using LEfSe: The higher abundance of Blautia, Prevotella, Alistipes, and Eggerthella were found at 6 weeks;Anaerostipes, Oscillospira, Enterococcus and Methanobrevibacter were determined at 12 weeks;and the higher abundance of Parabacteroides, Anaerofustis, Lactobacillus and Butyricimonas were determined at 16 weeks. Further functional predicted analysis by PICRUSt revealed that the endocrine system and car-bohydrate metabolism were significantly developed at 3 weeks. The development of the immune system was predicted to be mainly during 6 to 12 weeks, while cardiovascular diseases and circulatory system were during 12 to 16 weeks. In addition, the significantly negative correlation between Bacteroides and villus height, the significantly negative correlation between growth parameters (ADFI and FCR) and Bacteroides, Oscillospira and Alistipes;and the significantly positive relations between growth parameters (ADFI and FCR) and Bilophila, Lactobacillus, Rikenella and Anaerofustis were determi

关键词： 16S rRNA Caecal microbiota Laying hen Developmental stage Intestinal health

Dependence of dielectric properties on BT particle size in EP/BT composites

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Rare Metals 2006年第z2期25卷 250-254页

作者： yang xiaojun yang Zhimin MAO Changhui DU Jun Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China

The polymer-ceramic composites of epoxy resin (EP) and barium titanate (BT) were prepared. BT powders of different BT particle sizes from 100 nm to 1 μm were used in the preparation. The dielectric properties, such as dielectric constant, dielectric loss and electrical breakdown strength, of the EP/BT composites were studied. The morphology of the composites was characterized by the means of scanning electron microscopy (SEM). The results show that the dielectric constant of the composites is much higher than the epoxy matrix at frequency range from 1 kHz to 10 MHz, and it is also obviously dependent on the size of BT particles. The electrical breakdown strength of the composites decreases with the increase of the BT content. The dependence of electrical breakdown strength on BT particle sizes was also discussed.

关键词： dielectric property barium titanate (BT) EP/BT composites

Design and Experimental Verification of a Roll Control Strategy for Large Wingspan Flapping-Wing Aerial Vehicle

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Journal of Bionic Engineering 2024年第4期21卷 1644-1661页

作者： Rui Meng Bifeng Song Jianlin Xuan xiaojun yang Dong Xue School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang215400China

Most flapping-wing aircraft wings use a single degree of freedom to generate lift and thrust by flapping up and down,while relying on the tail control surfaces to manage ***,these aircraft have certain limitations,such as poor accuracy in attitude control and inadequate roll control *** paper presents a design for an active torsional mechanism at the wing's trailing edge,which enables differential variations in the pitch angle of the left and right wings during *** simple mechanical form significantly enhances the aircraft's roll control *** experimental verification of this mechanism was conducted in a wind tunnel using the RoboEagle flapping-wing aerial vehicle that we *** study investigated the effects of the control strategy on lift,thrust,and roll moment during flapping ***,the impact of roll control on roll moment was examined under various wind speeds,flapping frequencies,angles of attack,and wing ***,several rolling maneuver flight tests were performed to evaluate the agility of RoboEagle,utilizing both the elevon control strategy and the new roll control *** results demonstrated that the new roll control strategy effectively enhances the roll control capability,thereby improving the attitude control capabilities of the flapping-wing aircraft in complex wind field *** conclusion is supported by a comparison of the control time,maximum roll angle,average roll angular velocity,and other relevant parameters between the two control strategies under identical roll control input.

关键词： Roll control Bio-inspired Roll moment Flapping wing aerial vehicle