Adaptive trajectory generation based on real-time estimated parameters for impaired aircraft landing

ABSTRACT

This paper is motivated by a need to address the challenge of securing a safe landing after suffering from inflight impairment. In this paper, a new adaptive generalised model predictive static programming (G-MPSP) is developed to generate a safe emergency landing trajectory for impaired aircraft. Utilising the computationally efficient G-MPSP framework, the proposed algorithm enables adaptation of model parameters based on the prediction errors to ensure reasonable guidance performance. Based on the estimated parameters, a feasible landing trajectory is then generated by the flexible finite-horizon G-MPSP with input constraints. The integrated approach features explicit closed-form solutions for both parameter estimation and trajectory generation. Its effectiveness is demonstrated by simulations in the presence of parameter uncertainties and noises and by comparison studies with the non-adaptive G-MPSP.     

Preserving global features of fluid animation from a single image using video examples

We synthesize animations from a single image by transferring fluid motion of a video example globally.Given a target image of a fluid scene,an alpha matte is required to extract the fluid region.Our me...     

重庆市小城镇风貌特色规划的探讨

加快小城镇建设是统筹城乡发展、积极解决"三农"问题、推动城镇化进程的有效途径。而目前的快速发展中,重庆市小城镇传统的、具有差异性的城镇特色正逐渐缺失。该文通过对重庆市小城镇建设整体定位、风貌特色及规划体系建构的讨论,尝试提出较为系统的、具有可操作性的风貌规划策略,对小城镇建设与管理提供参照。     

连续梁顶推、落梁工艺及质量控制

针对重庆某大桥副跨为50×5＋36m顶推连续梁,其箱梁断面为单箱三室,分上下游各单室预制的特点,介绍连续梁顶推、落梁施工工艺和质量控制。     

新型连续流三维粒子电极反应器的设计及处理效能的研究

本项目在板框式反应器基础上设计制作出新型连续流三维粒子电极反应器,采用溶胶-凝胶法制备了负载Sb掺杂SnO2平板电极及粒子电极;以杀稗净农药废水为研究对象,优化了粒子电极的催化反应参数。     

Estimation of Travel Times on Signalized Arterials

This paper describes procedure for estimation of travel time on signalized arterial roads based on multiple data sources with application of dimensionality reduction. Travel time estimation approach incorporates forecast of transportation nodes impendence and travel time on network links. Forecasting period is two hours and the estimation is based on historical data and real time data on traffic conditions. Travel time estimation combines multivariate regression, principal component analysis, KNN （k-nearest neighbours）, cross validation and EWMA （exponentially weighted moving average） methods. When comparing estimation methodologies, relevantly better results were achieved by KNN method than with EWMA method. This is true for every time interval considered except for evening time interval when signalized arterial roads were uncongested.     

A geostatistical approach for groundwater head monitoring network optimisation: case of the Sfax superficial aquifer (Tunisia)

In many developing countries, the groundwater monitoring network is randomly designed, and consequently needs to be revised and optimised to reduce operation time and cost, remove redundant piezometric data, and strengthen sparseness data zone with supplementary observation well. The geostatistical approach used in this work is based on the universal kriging variance combined with cross‐validation test. Hence, a rational interpolation of water table elevations was performed to evaluate the accuracy of data employed in the piezometric head modelling. In this study, the groundwater monitoring network of the Sfax superficial aquifer in the south east of Tunisia was optimised. The elimination of five observation wells induces the invariability in the variance of estimate due to their less contribution in interpretations of the groundwater level behaviour. However, 38 wells were added at areas of high variance of the kriging in order to ameliorate the spatial coverage of the monitoring network.     

全力推进一级安全标准化企业创建促进企业高质量安全发展

中联同力推进成员企业积极创建国家一级安全标准化体系,建立安全生产责任和目标,指导和督促企业贯彻落实安全管理体系,防范安全风险,规范安全行为,排查治理事故隐患,使生产各环节符合安全生产法律法规和标准规范的要求,通过安全体系“计划、实施、检查、改进”PDCA动态循环模式,建立安全绩效持续改进的长效机制,实现安全健康管理系统化、岗位操作行为规范化、设备设施本质安全化、作业环境器具定置化,防止和减少生产安全事故。     

基于互协方差的L型嵌套阵列二维波达方向估计

为了解决L型均匀阵列波达方向（DOA）估计分辨率较低、估计信源数受限于阵元数、估计精度易受信噪比影响等问题,提出一种基于互协方差的L型嵌套阵列二维DOA估计算法。利用不同子阵间互协方差矩阵产生较长无冗余阵元的虚拟阵列,消除噪声干扰;利用虚拟阵列及其共轭矩阵构建等效协方差矩阵,实现虚拟阵列信号的解相干;采用旋转不变子空间技术对等效协方差矩阵进行处理,得到目标的角度信息;基于虚拟阵列等效信源的唯一性进行空间信源的角度匹配。对所提算法的DOA估计有效性进行仿真验证,结果表明,在阵元数相同情况下,该算法与L型均匀阵列相比在低信噪比环境下拥有更高的估计精度,能够辨识更多的空间信源。