Bandwidth sensitive fast failure recovery scheme for Metro Ethernet

Restoration in Ethernet has evolved over the years as specified in various standards: first the classical reconstruction of spanning trees was proposed in 802.1d; later 802.w specified RSTP to reduce the convergence time required in the STP protocol. Recently, the use of multiple spanning tree was suggested in 802.1s standard. In addition, there have been several proposals to implement multiple tree based restoration. Even though the results are promising they fall short of elevating Ethernet to a carrier grade technology. In this paper, we develop a distributed fast failure recovery spanning tree scheme, which restores lost facilities within tens of milliseconds. Recovery algorithm is localized around the point of failure on the spanning tree, thus avoiding disruption of the entire network. Failures are repaired using pre-configured sub spanning trees which are computed based on traffic requirements and resource availability. This paper also proposes possible enhancements to the failure recovery method using IEEE link aggregation standard to further reduce restoration time and provide differentiated survivability.     

Bruise detection on Jonagold apples by visible and near-infrared spectroscopy

The visible and near-infrared spectra of bruised and intact spots on Jonagold apples were acquired from 400 to 1700 nm with spectrophotometers. Multiplicative scatter correction (MSC) and Norris' first derivative were applied to pre-process the spectra. Afterwards, partial least squares (PLS) analysis was performed on the processed spectral data. In terms of the total classification accuracy, the Norris' first derivative processed data performed better than MSC processed data. A total classification accuracy of more than 90% could be achieved. This research shows that visible and near infrared spectroscopy has the potential to be used for detecting bruises on Jonagold apples.     

基于NTP的uIP协议栈改进与实现

传统uIP协议栈使用系统定时器作为时钟信号,在面向同步控制时容易引起服务器端设备的循环读取。针对这一问题,引入NTP网络授时协议和估计误差系数k,并通过测试确定误差系数k。通过定制uIP协议栈中的UDP报文格式,实现了NTP客户端的功能。在AVR Network网络开发板上进行了时钟偏移测试。测试结果表明ping响应控制在1 ms以内,平均时钟精度提高至0.002 9 ms。     

Frequency-domain iterative learning control of a marine vibrator

To the purpose of marine seismic acquisition, new acoustic sources have been developed to reduce the environmental impact. The use of marine vibrators makes it possible to define emission frequency ranges, consequently allowing limitation of the frequencies that disturb marine animal life. Constructing marine vibrators with high efficiency and linear dynamics is however difficult, and the vibrators suffer from both friction, backlash and high-order harmonics. These nonlinear effects, in combination with drifting dynamics, make the required control a crucial and challenging problem. This paper presents a model-based iterative learning control solution, performed in the frequency-domain. Additionally, an adaptive reidentification algorithm is developed to cope with drifting dynamics. The proposed solutions are successfully evaluated in experiments with a marine vibrator.     

高斯过程集成算法的发酵过程软测量建模

针对谷氨酸发酵过程一些关键参数不能在线测量而导致的建模精度不高的问题,Bagging和高斯过程回归算法相结合,提出一种基于Bagging算法集成高斯过程的软测量建模方法。该算法使用Bagging技术从训练样本集中选取若干子训练样本集,利用该若干子集形成许多高斯过程模型,并通过平均组合方式进行集成,得到最终的模型输出。将该集成算法应用到谷氨酸发酵过程的软测量建模中,实现了对谷氨酸浓度的准确预测,相对于单一高斯过程模型,具有更高的预测精度和鲁棒性。     

快速Blob分析算法在气门摇臂位置检测中的应用

针对基于机器视觉的气门摇臂安装位置检测中的高实时性图像处理要求,提出了一种基于游程的快速Blob分析算法．通过使用游程链表和动态数组,每个游程仅需扫描一次,不必与相邻所有游程进行比较．在算法中增加追溯扫描过程,消除标记冲突引起的标记误差,简化了判断过程,提高了操作效率．实验结果表明算法具有鲁棒、高效的特性,已在气门摇臂位置检测系统得到应用．     

Data-driven output-feedback fault-tolerant control for unknown dynamic systems with faults changing system dynamics

This paper studies the data-driven output-feedback fault-tolerant control (FTC) problem for unknown dynamic systems with faults changing system dynamics. In a framework of active FTC, two basic issues are addressed: the fault detection employing only the measured input–output information; the controller reconfiguration to achieve optimal output-feedback control in the presence of multiple faults. To detect faults and write the system state via the input–output data, an approach to data-driven design of a residual generator with a full-rank transformation matrix is presented. An output-feedback approximate dynamic programming method is developed to solve the optimal control problem under the condition that the unknown linear time-invariant discrete-time plant has multiple outputs. According to the above results and the proposed input–output data-based value function approximation structure of time-varying plants, a model-free output-feedback FTC scheme considering optimal performance is given. Finally, two numerical examples and a practical example of a DC motor control system are used to demonstrate the effectiveness of the proposed methods.     

No-reference image blur index based on singular value curve

We describe a new no-reference blur index for still images based on a singular value curve (SVC). The algorithm is composed of two steps. First, the singular value decomposition is performed on the image to be blur-assessed. Then an image blur index is constructed from the singular value curve. Experimental results obtained on four simulated blur databases and on the Real Blur Image Database show that the proposed SVC algorithm achieves high correlation against human judgments when assessing the blur distortion of images.