Multi-exposure image fusion aims to fuse a series of images with different exposures for the samescene, and it is the main-stream method for high dynamic range imaging. To obtain more realistic results, aMulti-Exposure image Fusion Network(MEF-Net) based on deep guided and self-learning is proposed. Thisnetwork is designed to fuse any number of images with different exposures in an end-to-end way, and generatethe best-fused results in an unsupervised way. In terms of the loss function, an intensity fidelity constraint termand the weighted Multi-Exposure image Fusion Structural SIMilarity(MEF-SSIM) are introduced to improvethe fusion quality. Moreover, a self-learning method is adopted to fine-tune and optimize the pre-learned model,considering the fusion problem of two images under extreme exposure to mitigate the halo phenomenongenerated by fusion. Based on abundant testing data, experimental results show that the proposed algorithmout performs other mainstream methods in terms of both quantitative measurement and visual fused quality

Rosacea is a chronic inflammatory skin disorder that manifests abnormal enhanced sensitivity to environmental stimuli. The decreased prevalence of rosacea in aged population has been reported, but the underlying mechanism is unclear. In this study, we confirm that the rosacea-like skin inflammation induced by cathelicidin LL37 is alleviated in aged mice and mice with progeria. Primary mouse keratinocytes isolated from aged mice and human dermal fibroblasts that undergo senescence present a much lower sensitivity to proinflammatory stimuli. Mechanistically, toll-like receptor 2 (TLR2) is downregulated in the skin of both aged population and mice. Knockdown of TLR2 in young human dermal fibroblasts mimics the attenuated immune response to LL37 and TNF-a evidenced in aged human dermal fibroblasts, whereas overexpression of TLR2 in aged human dermal fibroblasts rescued this attenuation. At the molecular level, in response to inflammatory stimuli, SIRT7 mediates the upregulation of TLR2, which promotes the activation of NF-kB signaling. The decay of SIRT7 confers an age-related decline of TLR2-NF-kB signaling. Although the overexpression of exogenous Sirt7 ab-rogates skin immune reactivity reduction in aged mice, loss of Sirt7 alleviates the rosacea-like features in mice. Thus, we reveal a SIRT7-TLR2-NF-kB axis that can be targeted for the improvement of rosacea. Journal of Investigative Dermatology (2022) 142, 2580e2590; doi:10.1016/j.jid.2022.03.026

针对GPS信号遮挡严重的室内环境下基于微惯性测量单元(MIMU)的行人导航系统导航定位误差随时间不断累积的问题,研究利用行人运动学特性建立双脚间步长约束的导航误差修正算法.将两个MIMU分别固定在行人双脚上,通过步态特性分析和零速区间检测,构建了结合单脚零速修正与双脚间步长约束的误差修正模型;通过加速度计输出数据推算步长实现约束的自适应调节,提高行人步态发生变化时的误差修正效果.实际行走实验结果表明,步长变化情况下,利用所提出方法推算步长的误差率在5.8％以下,修正后双脚位置误差相比固定步长约束减小约46.43％,轨迹更加符合实际.

随着2020年初新型冠状病毒肺炎疫情的爆发，线上课程已经成为国内高校常用的教学方式。本文通过《信号与系统》英文线上课程建设的具体实践，详细分析了线上英文教学的优势与局限，然后从线上教学、平时作业、课程实践和期末考试四个阶段出发，面向学生实际学习情况详细建设线上课程，从最终建设结果来看成效良好，可以为其他高校线上教学提供参考。

For the airborne SAR imaging, the motion compensation (MOCO) is required because of the phase error caused by the atmospheric turbulence. In the case of ultrahigh-resolution and wide-swath, the phase error may be range-dependent (RD), which may induce a RD residual-RCM after the correction of range cell migration (RCM) by using the range migration algorithm (RMA). Currently, phase gradient autofocus (PGA) is widely used to estimate the phase error from the raw data. However, the RD residual-RCM may degrade the accuracy of the PGA. To overcome such a problem, we present a CZT correction algorithm to correct the RD residual-RCM. Processing of airborne real data validates the effectiveness of the proposed algorithm.

To realize the individual navigation when losing GPS signal,a pedestrian navigation scheme based on micro inertial measurement unit (MIMU) is proposed.Since the inertial navigation error is accumulated with time,a dual-MIMU navigation scheme is given to correct the position estimation of the pedestrian navigation.Two MIMUs are fixedly connected on the individual's feet,and according to the gait characteristics when walking,the zero-speed detecting and correcting on the individual navigation results are conducted by using the zero-speed detector based on hypothesis testing and maximum likelihood estimation of the Generalized Likelihood Ratio Test.According to maximum step size constraint of individual walking,an ellipsoidal constraint Kalman filtering algorithm is designed to further adjust the individual navigation results.Experiment results show that the of the feet's positioning RMS error of the proposed method is reduced by 41.46％,compared with that of the method without feet-position constraint.

针对具有热流、动压、过载以及多个禁飞区约束的再入轨迹优化问题,提出采用序列凸优化方法快速求解.利用归一化时间作为自变量解决终端时间自由问题,并引入辅助控制变量以减少序列优化结果中的高频振荡,在此基础上,通过线性化、离散化和非凸约束的凸化处理,将非凸非线性优化问题转化为二阶锥规划(Second Order Conic Programming,SOCP)问题,然后采用凸优化求解算法快速求解.数值优化结果与对比验证表明该方法能快速高效求解多约束条件下的再入轨迹优化问题,且计算效率和性能均优于传统的非线性规划方法.

Toimprove the precision andtrackingperformance of indoor position system and adapttothe complex indoor environment, the position systems of pedestrian dead reckoning and ultrasonic transducerwereintegrated. What’s more, the fusion algorithm of noise power factors assisting covariance weighted fusion based on Square Root Unscented Kalman Filterwas proposed, and the globally optimal state estimation as feedbackwas introduced into the algorithm too. To solve the problem of measuring pedestrian’s course angle with ultrasonic, a simple and effective geometry methodwas proposed. The simulation resultshowsthat in the simulative and dynamic indoor environment including the influence of multipath effectandcumulative error of inertia device,the position accuracy of fusion algorithm is always better thanthat ofsingle position model’s. Moreover the fusion algorithm has good convergence performance, stability and adaptation performance. So the study has positive effect on indoor position research and application.

在个人导航和基于位置服务(LBS)领域,如何实现低成本、高可靠性、高精度、连续的室内定位仍是研究的热点;然而依靠单一技术的室内定位结果很难满足上述定位要求;文章用粒子滤波(PF)对INS和RFID技术进行融合;对低精度INS使用行人航迹推算算法(PDR),其中步数和步长由峰值检测和Weinberg算法分别测算;根据位置信息对RFID使用加权KNN算法;仿真结果表明:组合定位纠正了INS的累计误差和漂移,实现了自主可靠的连续定位,提高了定位精度,极大程度上优化了系统性能。

专业实验室是加强学生实际动手能力，培养学生想象力和创造力的主要场所，是专业建设中极为重要的环节。文章从探测制导与控制技术特色专业人才培养需求出发，结合中南大学航空航天学院的实际情况，探讨了国防特色专业实验室的建设和管理，以便为其他专业实验室的建设提供参考。

设计了一种基于低成本MEMS加速度计的无陀螺车载捷联惯导系统,将高精度的MEMS加速度计安放在载体非质心处,代替陀螺来测量载体角运动信息,实现车辆的GPS信号被遮挡时短时间内的导航定位定姿要求;仿真结果表明:对于300 s时间内导航的载体,无陀螺车载捷联惯导系统的位置误差达到了0.0002°,满足导航的精度要求。

A linear model including J2 perturbation in the Cartesian coordinates is presented for spacecraft formation flight.The Lagrange method is used to obtain this model by including the absolute effect on the reference orbit and the relative effect on the relative motion of the formation satellites under the J2 perturbation.This model accounts for the short-period perturbation of the orbital radius of the reference satellite and the angular velocities of the chief-fixed rotating reference frame,which also does not neglect the coupling terms between the out-of-plane and in-plane equations,thus leading to the improvement of accuracy.A numerical simulation illustrates that the relative trajectory error of this model is only 10% with respect to the nonlinear two body propagator model,and the relative radius error of the projected circular formation is less than 1%.At the same time,the model is linear state space form that is convenient to design the guidance,navigation and control system in formation flight missions.

针对飞机防滑刹车系统的复杂性和非线性,在分析滑移率控制式飞机防滑刹车系统的工作原理基础上,提出了一种基于无模型自适应控制的飞机防滑刹车控制算法;该算法无需精确的动力学模型,直接利用输入输出信息实现飞机防滑刹车的最佳滑移率控制;仿真结果表明:采用无模自适应防滑刹车控制算法,在5s之内就能获得稳定的滑移率,为提高飞机刹车的效率提供了一条新的思路。

Solving the problem of algorithm in modern communication channel,a new method of quasi-Newton least mean square adaptive equalization is proposed.By replacing inverse matrix calculation of LMS/Newton correlation function by symmetric positive-definite Hesse matrix,the proposed algorithm reduces the influence of traditional auto-correlation matrix estimate error for the algorithm convergence.Equalization simulation shows that higher convergence speed and lower bit error rate are obtained.

To solve the practical problem of inertial components de-noising in INS,a multi-scale real-time Kalman filtering based on interval orthogonal wavelet transform was proposed.With the ability of the interval wavelet transform to restrain terrible edge effects and its real-time decomposition characteristics in a sliding data window,a multi-scale dynamic systems framework for real-time Kalman filter was established.The results show that under the condition of given wavelet decomposition scale,the algorithm,while maintaining a certain real-time,has a good performance,and variances of filter errors are reduced by at least one order of magnitude.

The interval wavelet transforms are integrated with linear mean square(LMS) and new Quasi-Newton algorithm,from which a new Quasi-Newton LMS adaptive noise canceling in the interval discrete wavelet transform domain(IDWT-QNLMS) is presented.With good environmental adaptability,the algorithm can reduce the impact of the step-size factor selection and the input signal autocorrelation matrix estimate error on the convergence rate and steady-state error.The computer simulation results indicate that the higher convergence rate and stronger ability to eliminate noise are obtained by using this algorithm in comparison with other LMS algorithms,and the new algorithm is effectively applicable to adaptive noise canceling systems.

Sound environment,among several different kinds of ladders-or simple classroom,has been investigated and argued via grey correlative degree analysis.The point of view was presented,constructing harmonious sound field couldn't be despised in theater and the good quality of acouticst with sound absorption material.