Adaptive distributed synchronization of heterogeneous multi-Agent systems over directed graphs with time-Varying edge weights

Time-varying edge weights represent dynamical interactions between any two nodes in multi-agent systems (MASs). In this paper, we consider a synchronization problem for heterogeneous MASs over directed graphs with time-varying edge weights from a control-theoretic perspective. We seek for an adaptive control protocol that drives the synchronization error in the presence of time-varying edge weights to converge in terms of asymptotic stability. We propose a class of observer networks for estimating leaders and output regulation equation solvers built on directed graphs with time-varying edge weights. Finally, we use a simulation study to verify the effectiveness of the proposed protocol.     

Cooperative surrounding control with collision avoidance for networked Lagrangian systems

This paper investigates the cooperative surrounding control problem for networked multi-agent systems with nonlinear Lagrangian dynamics. With the consideration of the target with constant and time-varying velocity, two cooperative surrounding control algorithms with collision avoidance are proposed, in which possible collision among agents is prevented so as to achieve a more reliable and safer performance. For the case when the target has a constant velocity, a velocity observer is designed firstly for each agent. Secondly, to handle the nonlinear dynamics and avoid collisions, the neural networks and potential functions are used for the controller design. Then, the cooperative surrounding control algorithm is proposed such that all the agents surround the target with the desired relative positions. For the case when the target has a time-varying velocity, the velocity observer is designed under the assumption that the target’s partial acceleration is known for each agent. Then, the cooperative surrounding control algorithm is proposed such that the surrounding error between the target and each agent is bounded. The main difference between these two algorithms is that the former can ensure the collision avoidance among target and agents, while the latter can do so only among agents because the target’s velocity is time-varying. The Lyapunov theory is used to prove the stability of the cooperative surrounding control algorithms. The simulation illustrates the effectiveness of the theoretical results.     

异种胰岛移植中供体猪的筛选:现状与进展(英文)

猪胰岛细胞异种移植是一种极具潜力治疗糖尿病的方法。其临床应用主要面临两大挑战:高质量的活性胰岛短缺与异种免疫排斥反应。合适的猪供体筛选(年龄、性别、品系、基因表型)是获取充足的高性能胰岛移植物的重要前提,并可有效地减轻胰岛异种抗原性及体内异种排斥反应,进而延长移植物的功能存活时间。在文中,我们总结了异种移植中猪胰岛的相关研究进展,为供体猪的筛选提供了依据;同时表明了无特殊病原体的成年转基因猪可能是目前最佳的异种胰岛供体,有望在未来的临床研究中大规模应用。     

对修订《普通高等学校图书馆规程》的若干建议

对2002年教育部印发的《普通高等学校图书馆规程》(修订),从修订原则、谋篇布局,对高校图书馆的性质、目标的再认识,组织体制、运行机制的再完善,服务理念的再深化,网络服务的时代化,改革创新促管理等方面,按章节顺序逐条提出修订意见和理由。     

基于SCI引文的物流合作研究网络分析

本文基于社会网络分析方法,利用UCINET软件,以2008-2012年SCI收录的物流论文为基础,对世界物流研究领域的合作研究趋势、跨国家或地区的物流研究合作变化以及主要国家或地区间的合作研究情况进行了分析.研究发现近五年来在物流研究领域研究人员合作比较紧密,美国在物流合作研究领域占据最核心的地位,资源控制能力最强,而中国等亚洲国家的物流研究跨国家或地区的合作也不断增加.     

Mars entry guidance based on nonlinear model predictive control with disturbance observer

This paper investigates entry guidance of a capsule for pinpoint landing on Mars. In this scenario, the capsule is subject to the external disturbances caused by the atmosphere that can result in control saturation, and then undesired landing errors. To this end, a new guidance scheme to satisfy entry constraints, high-accuracy landing at high elevation sites, is proposed. The technical contributions of this work are two-fold: first, in order to mitigate the effects caused by large disturbance, a function describing the joint constraints of bank angle and slacked height is proposed; based on the nonlinear model predictive control (NMPC), a new algorithm is developed, where the constraints of dynamics, bank angle, slacked height, are sufficiently considered and precisely modeled; second, a state-space observer to improve the prediction of disturbance is introduced, which can significantly improve the accuracy of landing performance. The numerical simulations show the feasibility and validity of the proposed scheme.     

数字金融能够促进工业经济绿色转型发展吗？ ——基于规模以上工业企业数据经验分析

试图回答数字金融如何促进工业经济绿色转型的问题.运用北京大学数字普惠金融指数和2011—2018年我国30个省份的面板数据,对数字金融影响工业经济绿色转型的作用效果、作用机制等进行理论分析与实证检验,结果表明数字金融显著促进工业经济绿色转型,同时无论是数字金融的综合指数层面还是覆盖率指数、使用深度指数以及数字化程度指数层面,对工业经济绿色转型都具有显著的促进作用;机制分析表明数字金融促进工业经济绿色转型主要通过提高工业绿色技术研发能力和水平、提高工业企业经营绩效等途径机制予以实现;进一步研究表明,数字金融一方面通过提高工业企业融资效率进而提高其绿色技术研发能力和水平,从而促进工业经济绿色转型,另一方面通过提高工业企业创新创业水平进而提高其经营绩效水平,从而促进工业经济绿色转型.根据研究结论,提出努力提高数字金融发展水平,特别是提高数字金融的覆盖面积、使用深度以及数字化程度,支持工业行业创新创业发展,以及加强数字金融与新金融业态协同配合、促进数字技术与金融业务深度融合等对策建议.     

融合科学计量和知识可视化方法的技术预见模型研究

基于德尔菲法的技术预见活动方法体系在主观性方面存在较多争议,改善技术预见方法成为各国技术预见活动中普遍关注的问题。文章在分析已开展的技术预见主要方法和问题、科学计量和知识可视化方法在技术预见中的作用基础上,提出了区域产业科技创新规划和企业技术创新中的技术预见模型建议。     

Evaluation of wireless bat swing speed sensors

Batter swing speed is an important parameter in understanding the performance of baseball and softball players. A number of swing speed sensors have recently been introduced and are commercially available. The aim of this study was to compare three wireless swing sensors with high speed video. Swing speed from high speed video was measured by differentiating the position coordinates of tracking markers on the bat barrel. On average, the wireless bat swing sensors reported speeds 8% slower than that found from video tracking. The agreement was better at low swing speeds, suggesting that the current generation of wireless sensors is best suited for developing players. Spatial measures, such as swing angle, were not in good agreement with video tracking.