Adaptive output feedback stabilization for a class of nonlinear systems with inherent nonlinearities and uncertainties

This paper investigates the problem of adaptive stabilization by output feedback for a class of uncertain nonlinear systems. The distinguishing feature of such a class of systems is the presence of uncertain control coefficient and unmeasured states dependent growth with growth rate of polynomial‐of‐output multiplying an unknown constant. First, new high‐gain K‐filters with two dynamic gains are introduced, and an appropriate state observer is constructed based on the K‐filters. Then, motivated by the universal control idea, the backstepping scheme is successfully developed for the adaptive output feedback control design. By appropriate choice of the design parameters, the global stability of the closed‐loop system can be guaranteed. Finally, numerical simulations are provided to illustrate the correctness of the theoretical results. Copyright © 2010 John Wiley & Sons, Ltd.     

Coherent H∞ Control for Linear Quantum Systems With Uncertainties in the Interaction Hamiltonian

This work conducts robust H∞ analysis for a class of quantum systems subject to perturbations in the interaction Hamiltonian. A necessary and sufficient condition for the robustly strict bounded real property of this type of uncertain quantum system is proposed. This paper focuses on the study of coherent robust H∞ controller design for quantum systems with uncertainties in the interaction Hamiltonian. The desired controller is connected with the uncertain quantum system through direct and indirect couplings. A necessary and sufficient condition is provided to build a connection between the robust H∞ control problem and the scaled H∞ control problem. A numerical procedure is provided to obtain coefficients of a coherent controller. An example is presented to illustrate the controller design method.      

Underwater Localization for Multiple AUVs Based on Bearing and Range Measurements

A novel underwater localization algorithm for autonomous underwater vehicle （AUVs） is proposed. Taking aim at the high cost of the traditional ＂leader-follower＂ positioning, a ＂parallel＂ model is adopted to describe the localization problem. Under an unknown-but-bounded assumption for sensor noise, bearing and range measurements can be modeled as linear constraints on the configuration space of the AUVs. Merged these constraints, a convex polyhedron representing the set of all configurations consistent with the sensor measurements can be induced. Estimates for the,uncertainty in the position of a single AUV or the relative positions of two or more AUVs can then be obtained by projecting this polyhedron into appropriate subspaces of the configuration space. The localization uncertain region for each AUV can be recovered by an approximation algorithm to realize underwater localization for multiple AUVs. The deduced theoretically and the simulated results show that it is an economical and practical localization method for the AUV swarm.     

离散不确定系统分布式鲁棒融合滤波器设计

针对一类离散多传感器动态模型的不确定系统,将鲁棒滤波理论与数据融合技术相结合,基于参数依赖Lyapunov函数,研究该离散系统的鲁棒融合滤波器设计问题。在集中式鲁棒融合滤波器的基础上,探讨了分布式加权融合滤波器的设计方法,通过仿真实验比较了鲁棒融合滤波器的性能。结果表明,利用该分布式加权融合算法,不仅对于解决当系统模型中存在参数不确定性时的滤波问题有较好的鲁棒性能和较低的计算量,而且在多传感器系统中对于满足不同精度鲁棒融合滤波器的设计需要具有较大的灵活性。     

一种对不确定区域再分类的路面检测算法

路面检测是智能汽车领域的一个重要研究课题。基于学习的方法将获取的汽车前方的图像划分为一些区域,然后分别将这些区域分类为路面区域或非路面区域。由于现实场景的复杂性,存在一些既包含路面又包含非路面的不确定区域,只是将其分类为路面区域或非路面区域是不合理的。针对上述问题,提出了一种新的基于分割的路面检测算法,其核心是不确定区域再分类算法RCUR（Re-classification on Uncertain Regions）。该算法检测出不确定区域后,利用不同分割算法的互补性将不确定区域分割为若干子区域,通过对子区域的组合、分类可以有效地区分出不确定区域中的路面与非路面部分。实验表明该算法能够在现实场景中适应路面的多样性,提高路面检测的正确率,降低噪声对路面检测结果的影响。     

不确定数据库中概率top-k和排序查询算法

传感器网络等技术的广泛应用产生了大量不确定数据。近年来,对于不确定数据的处理和查询成为数据库和数据挖掘领域研究的热点。其中,传统关系数据库中的top-k查询和排序查询怎样拓展到不确定数据是其中的焦点之一。研究近年来提出的不确定数据库上top-k查询和排序查询算法,归纳和比较目前各种不同查询算法所适应的语义世界和应用场景,并详细分析各种算法的执行效率和算法复杂度。另外,对于不确定数据top-k查询和排序查询所面临的挑战和可能的研究方向进行了总结。     

Linear random vibration by stochastic reduced‐order models

A practical method is developed for calculating statistics of the states of linear dynamic systems with deterministic properties subjected to non‐Gaussian noise and systems with uncertain properties subjected to Gaussian and non‐Gaussian noise. These classes of problems are relevant as most systems have uncertain properties, physical noise is rarely Gaussian, and the classical theory of linear random vibration applies to deterministic systems and can only deliver the first two moments of a system state if the noise is non‐Gaussian. The method (1) is based on approximate representations of all or some of the random elements in the definition of linear random vibration problems by stochastic reduced‐order models (SROMs), that is, simple random elements having a finite number of outcomes of unequal probabilities, (2) can be used to calculate statistics of a system state beyond its first two moments, and (3) establishes bounds on the discrepancy between exact and SROM‐based solutions of linear random vibration problems. The implementation of the method has required to integrate existing and new numerical algorithms. Examples are presented to illustrate the application of the proposed method and assess its accuracy. Copyright © 2009 John Wiley & Sons, Ltd.     

不确定数据频繁项集挖掘方法综述

近几年来,不确定数据广泛出现在传感器网络、Web应用等领域中。不确定数据挖掘已经成为了新的研究热点,主要包括聚类、分类、频繁项集挖掘、孤立点检测等方面,其中频繁项集挖掘是重点研究的问题之一。综述了传统的频繁项集挖掘的两类基本算法,分析了在此基础上提出的适用于不确定数据以及不确定数据流的频繁项集挖掘的方法,并探讨了今后可能的研究方向。     

基于曼哈顿距离的不确定移动对象概率Skyline查询

在众多应用中,由于受到测量仪器精度、更新延迟、网络带宽等限制,不同形式的数据不确定性广泛存在。目前,不确定数据中的信息查询受到数据库研究领域学者的关注,并且为不确定数据寻找高效的分析方法也成为了一个热门课题。本文针对基于曼哈顿距离的不确定移动对象概率Skyline查询问题,提出一个基于曼哈顿距离的概率Skyline模型用于求解不确定移动对象在某时刻是Skyline的概率,并得到一个p-t-Skyline结果集,此集合包含所有在t时刻Skyline概率至少是p的移动对象。在实际应用中,计算大量不确定移动对象的Skyline概率过程繁琐,代价高昂。为提高概率Skyline查询过程的计算效率,本文提出包含“采样-限定-修剪-精炼”4个步骤的解决方案。同时,为进一步减少Skyline运算开销,本文使用一个多维索引结构VCI树以加快数据检索的效率。实验结果表明该解决方案在不同数据规模以及维度的数据集上均具有较高的效率。     

工时不确定条件下的车间作业调度技术

为解决工时偏差快速调整、多种调整要求综合协调的问题,提出了面向多品种、变批量生产模式的工时不确定条件下的车间作业动态调度技术。通过分析工时不确定条件下车间作业调度方案制定的不确定性、执行过程的动态性、变更影响的关联性以及响应的实时性内涵,提出了解决工时不确定下调度问题的缓解、隔离和快速响应相结合的处理策略;在对工序移动、变换顺序、调整设备和重调度处理流程综合分析的基础上,建立了统一的模块化作业调度方案动态调整流程;基于调度方案数据结构的建模,提出了受影响工序遍历及其关联树构建算法;提出了工时偏差容忍度的概念,实现了对调度问题影响范围的有效缓冲;提出了工时扰动偏差驱动下的前后移动调整、顺序调整、设备更换调整和重调度调整等动态调度算法,解决了作业计划与执行现场同步的问题。最后,通过实例分析说明了该技术的有效性。