State Estimation of Drive-by-Wire Chassis Vehicle Based on Dual Unscented Particle Filter Algorithm

Accurate vehicle dynamic information plays an important role in vehicle driving safety.However,due to the characteristics of high mobility and multiple controllable degrees of freedom of drive-by-wire chassis vehicles,the current mature application of traditional vehicle state estimation algorithms can not meet the requirements of drive-by-wire chassis vehicle state estimation.This paper proposes a state estimation method for drive-by-wire chassis vehicle based on the dual unscented particle filter algorithm,which make full use of the known advantages of the four-wheel drive torque and steer angle parameters of the drive-by-wire chassis vehicle.In the dual unscented particle filter algorithm,two unscented particle filter transfer information to each other,observe the vehicle state information and the tire force parameter information of the four wheels respectively,which reduce the influence of parameter uncertainty and model parameter changes on the estimation accuracy during driving.The performance with the dual unscented particle filter algorithm,which is analyzed in terms of the time-average square error,is superior of the unscented Kalman filter algorithm.The effectiveness of the algorithm is further verified by driving simulator test.In this paper,a vehicle state estimator based on dual unscented particle filter algorithm was proposed for the first time to improve the estimation accuracy of vehicle parameters and states.

Representation of the Stratospheric Circulation in CRA-40 Reanalysis:The Arctic Polar Vortex and the Quasi-Biennial Oscillation

The representation of the Arctic stratospheric circulation and the quasi-biennial oscillation(QBO)during the period 1981–2019 in a 40-yr Chinese global reanalysis dataset(CRA-40)is evaluated by comparing two widely used reanalysis datasets,ERA-5 and MERRA-2.CRA-40 demonstrates a comparable performance with ERA-5 and MERRA-2 in characterizing the winter and spring circulation in the lower and middle Arctic stratosphere.Specifically,differences in the climatological polar-mean temperature and polar night jet among the three reanalyses are within±0.5 K and±0.5 m s^(–1),respectively.The onset dates of the stratospheric sudden warming and stratospheric final warming events at 10 hPa in CRA-40,together with the dynamics and circulation anomalies during the onset process of warming events,are nearly identical to the other two reanalyses with slight differences.By contrast,the CRA-40 dataset demonstrates a deteriorated performance in describing the QBO below 10 hPa compared to the other two reanalysis products,manifested by the larger easterly biases of the QBO index,the remarkably weaker amplitude of the QBO,and the weaker wavelet power of the QBO period.Such pronounced biases are mainly concentrated in the period 1981–98 and largely reduced by at least 39%in 1999–2019.Thus,particular caution is needed in studying the QBO based on CRA-40.All three reanalyses exhibit greater disagreement in the upper stratosphere compared to the lower and middle stratosphere for both the polar region and the tropics.

基于皮肤本态数据库的中青年女性面部皮肤综合状态评价模型构建

从中国女性皮肤本态数据库(北京工商大学)中随机抽取22~42岁女性志愿者1 085例,采集志愿者的皮肤数据,通过相关性分析初步降噪,得到皮肤状态核心指标,并采用KMO检验和巴利特球形检验方法进行检验。根据主成分分析法计算评价模型的各项系数,最终构建皮肤状态综合评价模型。皮肤状态相关的核心指标包括:年龄、皮肤总弹性、皮肤光泽度、黑色素含量、血红素含量、水分含量、经皮水分散失量、肤色ITA°、油脂含量、毛孔数量等10项。该模型对女性的综合皮肤状态给予客观的量化判定,弥补了肉眼判断受到的周围环境以及个人主观意识的影响,解决了皮肤评价的时空限制,采集相关指标数据即可对女性皮肤进行有效评价。研究结果可为女性皮肤状态综合判定提供技术支持。

Effects of Estrogen on Mucosal Structure and Numbers and Distribution of Intraepithelial Lymphocytes and Goblet Cells in Small Intestine of Rats

To study the effects of estrogen on the structure of the intestinal mucosal barrier, 18 healthy female Wistar Rats underwent estrus synchronization. In diestrus, they were divided into three groups: one sham operated control group (SHAM); one ovariectomized group (OVX); and one ovariectomized plus estradiol benzoate group (OVX+E2). Intestinal mucosal epithelial cells, intraepithelial lymphocytes (IEL), and goblet cells (GCs) were observed by light microscope. The results showed that in the OVX group, the intestinal mucosa damaged obviously, the villus atrophied, the ratio of villus height to crypt depth reduced, and the number of IELs and GCs reduced. The indicators of OVX+E2 group were significantly higher than OVX group, but some indicators were lower than SHAM. These indicated that the function of intestinal mucosal barrier was greatly damaged in ovariectomied rat, and proper dosage of estradiol benzoate would improve the function of small intestinal mucosal barrier in ovariectomied rat to some degree.

Video Recognition for Analyzing the Characteristics of Vehicle–Bicycle Conflict

Vehicle–bicycle conflict incurs a higher risk of traffic accidents,particularly as it frequently takes place at intersections.Mastering the traffic characteristics of vehicle–bicycle conflict and optimizing the design of intersections can effectively reduce such conflict.In this paper,the conflict between right-turning motor vehicles and straight-riding bicycles was taken as the research object,and T-Analyst video recognition technology was used to obtain data on riding(driving)behavior and vehicle–bicycle conflict at seven intersections in Changsha,China.Herein,eight typical traffic characteristics of vehicle–bicycle conflict are summarized,the causes of vehicle–bicycle conflict are analyzed using 18 factors in three dimensions,the internal relationship between intersection design factors and traffic conflicts is explored,and the guiding of design optimization based on the width of bicycle lanes and the soft separation between vehicles and bicycles is discussed.The results showed that colored paved bicycle lanes were better,performing better at a width of 2.5 m compared to 1.5 m.However,the colored pavement was not suitable for the entire road and had to be set at the position,at which the trajectories of a bicycle and motor vehicle overlapped.Thus,a 2.5-m-wide bicycle lane provides good safety.However,there are still defects in the existing safety indicators,so it is necessary to develop new indicators to reflect real vehicle–bicycle conflict situations more comprehensively.

A potential-driven switch of activity promotion mode for the oxygen evolution reaction at Co_(3)O_(4)/NiO_(x)H_(y) interface

Co_(3)O_(4)spinel oxides have manifested promising activity toward the oxygen evolution reaction(OER)through effective modifications.For them to become top electrocatalysts,however,accurate accounts of the catalytic kinetics are essential to gain a deep understanding of the activity promotion mechanisms.Herein,we use a newly proposed kinetic model based on energetic span as the rate-determining term for the electrocatalytic reaction to throw light on the promotion mechanism of Co_(3)O_(4)interfaced with nickel hydroxides(NiO_(x)H_(y))for the OER.We find that depending on the electrode potential,the OER kinetics at the designed interface between Co_(3)O_(4)and NiO_(x)H_(y)are boosted in entirely different ways.As a result,the OER can occur at a lower onset potential as well as a low Tafel slope.This work emphasizes the benefit of using rational theoretical models for electrocatalyst design.

Integrated microdevice with a windmill-like hole array for the clog-free,efficient,and self-mixing enrichment of circulating tumor cells

Circulating tumor cells(CTCs)have tremendous potential to indicate disease progression and monitor therapeutic response using minimally invasive approaches.Considering the limitations of affinity strategies based on their cost,effectiveness,and simplicity,size-based enrichment methods that involve low-cost,label-free,and relatively simple protocols have been further promoted.Nevertheless,the key challenges of these methods are clogging issues and cell aggregation,which reduce the recovery rates and purity.Inspired by the natural phenomenon that the airflow around a windmill is disturbed,in this study,a windmill-like hole array on the SU-8 membrane was designed to perturb the fluid such that cells in a fluid would be able to self-mix and that the pressure acting on cells or the membrane would be dispersed to allow a greater velocity.In addition,based on the advantages of fluid coatings,a lipid coating was used to modify the membrane surface to prevent cell aggregation and clogging of the holes.Under the optimal conditions,recovery rates of 93%and 90%were found for A549 and HeLa cells in a clinical simulation test of our platform with a CTC concentration of 20-100 cells per milliliter of blood.The white blood cell(WBC)depletion rate was 98.7%(n=15),and the CTC detection limit was less than 10 cells per milliliter of blood(n=6).Moreover,compared with conventional membrane filtration,the advantages of the proposed device for the rapid(2 mL/min)and efficient enrichment of CTCs without clogging were shown both experimentally and theoretically.Due to its advantages in the efficient,rapid,uniform,and clog-free enrichment of CTCs,our platform offers great potential for metastatic detection and therapy analyses.