Comments on “Adaptive ILC for a class of discrete-time systems with iteration-varying trajectory and random initial condition”

This note points out some errors in the proof of the asymptotic learning convergence of the tracking error in Chi, Hou and Xu [Chi, R.H., Hou, Z.S., & Xu, J.X. (2008) Adaptive ILC for a class of discrete-time systems with iteration-varying trajectory and random initial condition. Automatica, 44(8), 2207-2213].     

毫米波雷达微弱行人轨迹跟踪-预测一体化方法

针对城市道路场景微弱行人目标雷达回波信号极易被强背景杂波淹没,导致目标轨迹跟踪及预测失效难题,提出了一 种基于调频连续波-多输入多输出毫米波雷达的微弱行人轨迹跟踪-预测一体化方法。 首先,利用递归贝叶斯检测前跟踪算 法,直接从未经阈值处理的雷达三维原始频谱数据中提取目标运动轨迹,解决了传统阈值决策信息丢失带来的跟踪性能下降问 题,并在此基础上提出了一种基于 Transformer 的端到端轨迹预测模型,进一步挖掘隐藏在跟踪轨迹中的时空相关性,完成了微 弱行人目标轨迹的精准预测。 实验结果表明,方法在信噪比大于-20 dB 时,预测轨迹的平均位移误差和最终位移误差分别小 于 0. 706、1. 215 m,均优于高斯过程、长短期记忆网络等传统方法。     

The design process and the ‘crisis’ in the UK information technology industry

The competitive position of UK information technology (IT) manufacturers in the expanding markets for IT equipment is declining. A recent report published by the National Economic Development Council (NEDC)¹ describes the situation facing the UK IT industry as one of ‘crisis’.This paper reports some of the findings of an investigation, conducted by the Design Innovation Group at the Open University, into the role of design in the competitiveness of manufacturers of IT equipment. The approach to design and development of four UK companies is examined in detail. It is argued that the supplier's lack of attention to design for user needs contributes to the ‘crisis’ situation expressed by the NEDC.     

Contributors to ozone episodes in three U.S./Mexico border twin-cities

The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of ± 15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma.     

考虑地层方位漂移特性的定向井轨道设计方法

按照地层划分方位漂移规律进行了定向井轨道设计,建立了井眼轨道的自然曲线模型,给出了更为简洁的井眼轨道数学模型。分析了井斜单元和方位单元之间的耦合关系,得到了计算单元的划分方法。论述了定向井和水平井方位漂移轨道设计的特点,提出了约束方程和设计方法。解决了按地层划分方位漂移规律的井眼轨道设计问题,适用于各种定向井和水平井的漂移轨道设计。定向井和水平井的设计实例验证了该设计方法的科学性和实用性。     

Combining group-based trajectory modeling and propensity score matching for causal inferences in nonexperimental longitudinal data.

A central theme of research on human development and psychopathology is whether a therapeutic intervention or a turning-point event, such as a family break-up, alters the trajectory of the behavior under study. This article describes and applies a method for using observational longitudinal data to make more transparent causal inferences about the impact of such events on developmental trajectories. The method combines 2 distinct lines of research: work on the use of finite mixture modeling to analyze developmental trajectories and work on propensity score matching. The propensity scores are used to balance observed covariates and the trajectory groups are used to control pretreatment measures of response. The trajectory groups also aid in characterizing classes of subjects for which no good matches are available. The approach is demonstrated with an analysis of the impact of gang membership on violent delinquency based on data from a large longitudinal study conducted in Montréal, Canada. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

产品设计中用户需求的系统化分析方法

对产品设计师来说,用户需求分析的重要性都是毋庸置疑的。本文分析了用户需求对产品设计内容的决定性作用,提出了用户需求的分类和系统化分析方法,并以不同实例说明了用户需求的系统化分析方法在产品设计过程中的应用。     

基于人性化网站界面设计的用户建模

为了能够实现网站界面风格的人性化和和谐化,通过对部分用户的调查来研究用户因素和网页界面因素之间的相互关系,并从错综复杂的用户和网页界面因素中提取起决定性作用的因素.基于这些决定性因素,用神经网络的方法建立了一个用于个性化网站界面风格和布局设计的用户模型.利用所建立的模型设计了一个针对老年人的网页界面,经过测试验证,此模型能收到良好的效果,提高了用户对网站界面风格和布局的整体满意度.     

三维井眼抽油杆与油管防偏磨技术研究与应用

抽油杆、管偏磨主要受力学因素和油井产出物的影响,其根本原因是抽油杆、管之间的摩擦力造成的;偏磨点的预测模型由实测数据进行修正或标定使预测更加准确;降低抽油杆、管之间的偏磨方法主要是降低杆、管之间的摩擦力;降低抽油杆对油管的正压力采用传力式加重杆加重,使抽油杆中和点下移;使用抽油杆防偏磨节箍,降低了杆、管之间的摩擦系数;现场应用219口井表明,延长了检泵周期、提高了井下效率和经济效益。     

国内外水平井钻井技术现状初探

由于水平井技术和其它技术一起能提高油田的采收率，所以近几年国外水平井技术和在水平井基础上发展起来的其它有关技术得到长足的发展。大位移井钻井技术，除了钻井装置强化外，井眼轨迹控制方式、测井方式和完井方式等都发生了变化，使水平位移达到8000m以上。多分支水平井技术，解决了封隔性、进入性和液压密封性难题，可望在更广的范围内应用。这些技术的发展都依赖于工具、仪器和设备的不断升档升级。我国应加强科研力度，进一步提高水平井技术的综合能力。