基于残差决策的自动飞行控制系统远程实时故障诊断

针对自动飞行控制系统结构复杂、关联部件众多,发生故障时诊断时间长,从而影响飞机运行效率的问题,提出一种基于飞机通信寻址报告系统(ACARS)的远程实时故障诊断方案。首先,分析自动飞行控制系统的故障特点,设计搭建检测滤波器;然后,利用ACARS数据链实时发送的自动飞行控制系统的关键信息进行相关部件的残差计算,并根据残差决策算法进行故障诊断及定位;最后,针对不同故障部件残差间的差异大、决策门限无法统一的缺点,提出基于二次差值的残差决策改进算法,减缓了检测对象的整体变化趋势,降低了随机噪声和干扰的影响,避免了将瞬态故障诊断为系统故障的情况。实验仿真结果表明,基于二次差值的改进残差决策算法避免了多决策门限的复杂性,在采样时间为0.1 s的情况下,故障检测所需时间大约为2 s,故障检测时间大幅降低,有效故障检测率大于90%。     

Championing and promoting innovation in UK megaprojects

In this article we explore the role of innovation champions and the ways innovation is championed and promoted in five selected UK megaprojects. To date, this research area is surprisingly under-explored in the megaproject management literature. The study is based on thirty interviews with innovation champions to capture their own perceptions and narratives on the ways innovation is stimulated and promoted in megaprojects, combined with relevant textual materials. Innovation was commonly defined as a step change or best practice that creates value that could be financial, environmental, societal etc. The data demonstrate the role of CEOs and their collaboration with innovation champions and academic partners in introducing innovation into the vocabulary of megaprojects, developing and formalising innovation strategy, and transferring experiences across megaprojects. The data show the ways different communication channels are used to promote innovations by champions such as forums, portals, platforms, campaigns, events etc.     

Event-triggered controller design of nonlinear discrete-time networked control systems in T-S fuzzy model

This article is concerned with event-triggered fuzzy control design for a class of discrete-time nonlinear networked control systems (NCSs) with time-varying communication delays. Firstly, a more general mixed event-triggering scheme (ETS) is proposed. Secondly, considering the effects of the ETS and communication delays, based on the T-S fuzzy model scheme and time delay system approach, the original nonlinear NCSs is reformulated as a new event-triggered networked T-S fuzzy systems with interval time-varying delays. Sufficient conditions for uniform ultimately bound (UUB) stability are established in terms of linear matrix inequalities (LMIs). In particular, the quantitative relation between the boundness of the stability region and the triggering parameters are studied in detail. Thirdly, a relative ETS is also provided, which can be seen as a special case of the above proposed mixed ETS. As a difference from the preceding results, sufficient conditions on the existence of desired fuzzy controller are derived to ensure the asymptotic stability of the closed-loop system with reduced communication frequency between sensors and controllers. Moreover, a co-design algorithm for simultaneously determining the gain matrices of the fuzzy controller and the triggering parameters is developed. Finally, two illustrative examples are presented to demonstrate the advantage of the proposed ETS and the effectiveness of the controller design method.     

Enriching Context Information for Entity Linking with Web Data

Journal of Computer Science and Technology - Entity linking (EL) is the task of determining the identity of textual entity mentions given a predefined knowledge base (KB). Plenty of existing...     

Looking at both sides of relationship dynamics in virtual communities: A social exchange theoretical lens

This study draws on social exchange theory to investigate the relationship dynamics of the member–community dyad in virtual community settings. Using a longitudinal design and multiple measurement sources, the findings indicate that social and task communication styles have unique effects on members’ community commitment velocity, which in turn influences member gratitude and entitlement behaviors. A moderated path analysis demonstrates that the effects of social and task communication styles on community commitment velocity are both positively moderated by attachment anxiety and attachment avoidance. It also reveals that members’ level of popularity augments the influence of community commitment velocity on member entitlement behavior.     

基于消息队列的通信系统异步传送控制仿真

传统方法对通信系统异步传送控制效果不佳,存在信号干扰及传送时间间隔较长等问题。为此引入消息队列技术,提出一种新的传送控制方法来解决以上问题。对通信系统的空时信道进行空时编码设计,实现空时信道的编码增益与分集增益;利用空时编码实现通信系统中继节点的空间分集,根据空间分集结果制订异步空时传送方案;采用消息队列技术构建通信系统异步传送控制模型,实现通信系统的异步传送控制。为了验证所提方法异步传送控制效果,设计对比实验。实验结果表明,上述方法的传送时间间隔较短,抗干扰能力强,平均分集增益高,说明所提方法更适用于通信系统的异步传送控制。     

Scheduler-based state estimation over multiple channels networks

We investigate the remote state estimation problem for networked systems over parallel noise-free communication channels. Due to limited network capabilities in practical network environments, communication schedulers are implemented at the transmit side of each subchannel to promote resource efficiency. Specifically, the processed signals are transmitted only when it is necessary to provide the real-time measurements to the remote estimator. The recursive approximate minimum mean-square error estimator is established to restore the state vector of a target plant by utilizing the scheduled transmission signals. All the information coming from the individual subchannels, even if no measurement is sent, will contribute to improve the estimation performance in an analytical form. Finally, a numerical example is given to illustrate the effectiveness of the main results.     

淮北矿业集团煤矿瓦斯监控集成系统数据采集协议的分析

淮北矿业集团是个拥有13对生产矿井，3个大型选煤厂，年产达原煤2000万t国有特大型企业。随着煤炭行业信息化和网络化的发展，淮北矿业集团采用了多种不同安全生产瓦斯监测监控系统，并在实际应用当中发挥了重要的作用，但出于国内生产的各种安全生产监测监控系统多为封闭系统，互不兼容。     

气液联合冲击器参数优化设计

分析了液压冲击器冲击机构的控制形式,得出气液联合冲击器采用后腔控制式的结构比较合理。经理论分析与计算表明，在多档冲击器的某一档上确定的最优抽象设计变量α，在其它各档上也同样适合。以此为基础得出了冲击活塞系统的基本参数设计计算公式，并以液压冲击器供油峰值流量最小为优化设计目标，进行了优化设计，求得了抽象设计变量最优值αu。     

信息科技在采矿工业中的应用与展望

采矿等传统产业要实现飞跃发展，必须与信息科技相结合。从计算机技术、人工智能、通信技术等三个方面阐述了信息科技在采矿工业中的应用与发展；最后指出：目前我国矿山企业信息化改造的薄弱环节是生产 技术的改造，有必要将信息技术直接嵌入到采矿生产工艺与过程中去。