音乐数据库的基于内容检索及一种基于ICA算法的按调查询系统的提出

目前音频数据库的研究相对于图象处于滞后,文中侧重音乐角度,结合MPEG标准和基于内容检索的应用,综述了音频检索的研究现状,分析了音频方面研究的特殊性和相关应用中的问题;并提出基于独立分量分析（ICA）的按调查询（QBH）的系统,较好地解决了特征提取中的鸡尾酒会效应问题。系统的查询结果置于三维声效环境中加速了查询。     

SGCMG系统框架角轨迹跟踪自适应补偿控制

作为应用在航天器上的惯性执行机构,单框架控制力矩陀螺（GSGCMG）系统框架角空间的轨迹跟踪性能对航天器姿态控制（或稳定）精度有着极大的影响,为提高SGCMG系统框架角轨迹跟踪性能,本文在轨迹跟踪控制中,采用了“PD＋自适应补偿”的控制器结构,通过分析可以发现,此种控制器不但可使轨迹跟踪误差收敛至零,实现有限时间跟踪控制,而且可使轨迹跟踪误差每一分量的绝对值指数收敛,对应用在航天器上的金宁塔形4－SGCMG系统框架角空间轨迹跟踪控制的仿真结果表明,上述控制算法是可行的。     

Detection and Tracking of Multiple,Partially Occluded Humans by Bayesian Combination of Edgelet based Part Detectors

Detection and tracking of humans in video streams is important for many applications. We present an approach to automatically detect and track multiple, possibly partially occluded humans in a walking or standing pose from a single camera, which may be stationary or moving. A human body is represented as an assembly of body parts. Part detectors are learned by boosting a number of weak classifiers which are based on edgelet features. Responses of part detectors are combined to form a joint likelihood model that includes an analysis of possible occlusions. The combined detection responses and the part detection responses provide the observations used for tracking. Trajectory initialization and termination are both automatic and rely on the confidences computed from the detection responses. An object is tracked by data association and meanshift methods. Our system can track humans with both inter-object and scene occlusions with static or non-static backgrounds. Evaluation results on a number of images and videos and comparisons with some previous methods are given. Electronic Supplementary Material Supplementary material is available in the online version of this article at     

FireFly: a cross-layer platform for real-time embedded wireless networks

We propose a cross-layer approach with tightly-coupled time synchronization for real-time support and predictable lifetime in battery-operated sensor networks. Our design spans a sensor hardware platform with hardware-based global time synchronization, a TDMA link layer protocol with collision-free multi-hop support and node scheduling algorithms for maximum concurrency and streaming. Our dual-radio sensor platform, FireFly, features an IEEE 802.15.4 transceiver and supports global time synchronization indoors by using an AM radio carrier-current method and an atomic clock receiver for outdoors. A TDMA-based link protocol, RT-Link, leverages the hardware for fixed and mobile nodes with a near-optimal and predictable node lifetime of over 2 years. It outperforms comparable sensor network link protocols such as B-MAC and S-MAC in terms of end-to-end latency and throughput and node lifetime across all duty cycle ratios. Operating over RT-Link is MAX, a scheduling framework which offers optimal transmission concurrency and bandwidth management for networks with regular structure. Through analysis and experiments we show that global time sync is a robust, economical and scalable alternative to in-band software-based techniques. To illustrate the capabilities and flexibility of our platform, we describe our experiences with two-way voice streaming over multiple hops. We have deployed a 42-node network with sub-100 μs synchronization accuracy in the NIOSH experimental coal mine for people-tracking and voice communication.

Real-time predictive zoom tracking for digital still cameras

Zoom tracking is becoming a standard feature in digital still cameras (DSCs). It involves keeping an object of interest in focus during the zooming-in or zooming-out operation. Zoom tracking is normally achieved by moving the focus motor in real-time according to the so-called trace curves in response to changes in the zoom motor position. A trace curve denotes in-focus motor positions versus zoom motor positions for a specific object distance. A zoom tracking approach is characterized by the way these trace curves are estimated and followed. In this paper, a new zoom tracking approach, named predictive zoom tracking (PZT), is introduced based on two prediction models: auto-regressive and recurrent neural network. The performance of this approach is compared with the existing zoom tracking approaches commonly used in DSCs. The real-time implementation results obtained on an actual digital camera platform indicate that the developed PZT approach not only achieves higher tracking accuracies but also effectively addresses the key challenge of zoom tracking, namely the one-to-many mapping problem.

Real time 3D face and facial feature tracking

Detecting and tracking human faces in video sequences is useful in a number of applications such as gesture recognition and human-machine interaction. In this paper, we show that online appearance models (holistic approaches) can be used for simultaneously tracking the head, the lips, the eyebrows, and the eyelids in monocular video sequences. Unlike previous approaches to eyelid tracking, we show that the online appearance models can be used for this purpose. Neither color information nor intensity edges are used by our proposed approach. More precisely, we show how the classical appearance-based trackers can be upgraded in order to deal with fast eyelid movements. The proposed eyelid tracking is made robust by avoiding eye feature extraction. Experiments on real videos show the usefulness of the proposed tracking schemes as well as their enhancement to our previous approach.

时滞大系统分散鲁棒跟踪控制器设计: LMI 方法

针对一类满足匹配条件的不确定性关联时滞系统,导出了分散鲁棒输出跟踪控制器存在的充分条件。基于不确定项的表达形式,给出了存在分散鲁棒跟踪控制器的线性矩阵不等式（LMI）条件。通过建立求解受LMIs约束的凸优化问题,提出了具有较小反馈增益LMI设计方法,使受控系统渐近跟踪给定的参考输入。仿真示例说明了该方法的应用。     

动态滑模控制及其在移动机器人输出跟踪中的应用

针对轮式移动机器人的输出跟踪问题,提出一种动态滑模控制方法,首先给出机器人的动力学简化模型,然后将其分解成两个低阶子系统,并给出其输出跟踪的动态滑模控制器设计方法,仿真试验表明该方法能明显地削弱滑模控制系统的抖振。     

超混沌系统自周期轨道链接式控制

基于混沌同步和周期轨道理论提出一种超混沌系统自周期轨道链接式控制法。从超混沌系统状态变量的时间序列中提取周期轨道并用于对系统的实时控制,可使混沌系统稳定运行于某一周期轨道。将提周期轨道经链接组合后用于系统控制,可得到大量的大周期轨道。对4阶蔡氏电路进行数字仿真实验,获得了满意的结果。     

连续时间混沌系统控制与同步的状态反馈方法

将连续时间混沌系统的控制与同步问题统一处理,在系统的非线性是Lipschitz非线性的条件下,基于Lyapunov稳定性理论,提出一种实现连续时间混沌系统控制与同步的状态反馈方法。无论驱动系统处于何种状态,该方法都可使响应系统按照驱动系统给定的轨道演化。该方法对系统参数不匹配及噪声干扰具有一定的鲁棒性。数值仿真结果表明了所提出方法的有效性。