Stability analysis and H∞ control for hybrid complex dynamical networks with coupling delays

This paper formulates and studies a model of complex dynamical networks with switching topology and coupling delays. Based on the hybrid control and Lyapunov function, the stability and robust H_∞ control of such networks with impulsive and switching effects, which have not been studied before, are addressed with some criteria derived. Examples are given to illustrate the effectiveness of the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.     

Delay‐dependent stability for Markovian genetic regulatory networks with time‐varying delays

This paper is concerned with the problem of stochastic stability analysis for a class of genetic regulatory networks with Markovian jump parameters and time‐varying delays. A delay‐dependent stability criterion is derived by using a novel mode‐dependent Lyapunov functional. The derived stability criterion is expressed in terms of linear matrix inequalities and is less conservative than the existing ones in the literature. A numerical example is provided to demonstrate the effectiveness of the proposed stability criterion. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Comparing ANN and GMM in a voice conversion framework

In this paper, we present a comparative analysis of artificial neural networks (ANNs) and Gaussian mixture models (GMMs) for design of voice conversion system using line spectral frequencies (LSFs) as feature vectors. Both the ANN and GMM based models are explored to capture nonlinear mapping functions for modifying the vocal tract characteristics of a source speaker according to a desired target speaker. The LSFs are used to represent the vocal tract transfer function of a particular speaker. Mapping of the intonation patterns (pitch contour) is carried out using a codebook based model at segmental level. The energy profile of the signal is modified using a fixed scaling factor defined between the source and target speakers at the segmental level. Two different methods for residual modification such as residual copying and residual selection methods are used to generate the target residual signal. The performance of ANN and GMM based voice conversion (VC) system are conducted using subjective and objective measures. The results indicate that the proposed ANN-based model using LSFs feature set may be used as an alternative to state-of-the-art GMM-based models used to design a voice conversion system.     

Distributed match-making

In many distributed computing environments, processes are concurrently executed by nodes in a store- and-forward communication network. Distributed control issues as diverse as name server, mutual exclusion, and replicated data management involve making matches between such processes. We propose a formal problem called distributed match-making as the generic paradigm. Algorithms for distributed match-making are developed and the complexity is investigated in terms of messages and in terms of storage needed. Lower bounds on the complexity of distributed match-making are established. Optimal algorithms, or nearly optimal algorithms, are given for particular network topologies.The work of the second author was supported in part by the Office of Naval Research under Contract N00014-85-K-0168, by the Office of Army Research under Contract DAAG29-84-K-0058, by the National Science Foundation under Grant DCR-83-02391, and by the Defence Advanced Research Projects Agency (DARPA) under Contract N00014-83-K-0125. Current address of both authors: CWI, Kruislaan 413, 1098 SJ Amsterdam, The Netherlands.     

基于压缩感知的无线传感器网络的数据编码

近年来,基于压缩感知的无线传感器网络数据编码的研究取得了一定的进展,但大部分研究是基于"单跳"的传输模型或者没有考虑网络内节点之间的合作。本文提出了一种基于压缩感知和分簇的传感器网络数据编码方法。首先,节点根据自己的编号伪随机的产生一个M维的列向量,把感知的数据xi投影到此向量上,然后把自己的编号和投影的数据一同传输给簇头。簇头把收到的数据进行求和,并且把计算后的结果传送给下一个簇头,直到sink节点。通过仿真实验和理论分析,验证了本文提出的方法比传统的方法能更好地减少网络内数据传输量。     

栅栏覆盖最大化生存周期调度算法

栅栏覆盖是近年来无线传感器网络的研究热点之一,如何延长生存周期是无线传感器网络研究的一个重要问题。针对无线传感器网络的栅栏覆盖应用,设计了两种最大化网络生存周期的调度算法:集中式的Greedy调度算法和分布式的DBCS调度算法。仿真实验表明:两种算法显著地延长了网络的生存周期;在较稀疏的网络中,DBCS算法与Greedy算法性能接近,分布式的DBCS算法适合应用于大规模传感器网络。     

一种无线链状网络路由算法的研究与应用

文章基于货运列车状态监控的无线传感器网络应用,针对网络节点能量有限以及链状网络节点负载不均衡的问题进行分析和研究,提出一种适合该应用的新型路由算法,该算法基于网络节点可通过功率控制来调整通信距离这一前提,为每个传感器节点选择合适的数据传输路径,以达到整个网络节省能耗,负载均衡的目的。仿真结果验证了该算法有效地平衡了网络负载,节省了网络能量,提高了网络生命周期。     

焊缝跟踪技术的研究与展望

本文回顾了电弧焊接的焊缝跟踪技术，并重点对该技术的发展趋势进行了介绍与分析，     

基于改进YOLOv3的运动目标分类检测算法研究

提出一种基于改进YOLOv3算法的一类运动目标检测算法. 为进一步提高YOLOv3的检测精度,采用基于DIoU优化的边界框回归损失函数进行计算; 优化非极大值抑制,有效减少了目标框重叠的现象,提高检测精度; 针对运动目标检测,提出一种基于目标框多中心点位移的检测算法. 经UA-DETRAC数据集上的实验表明,改进后的算法在提高检测精度的同时保证了较快的速度,准确率和召回率相比原始YOLOv3分别提高了 8.07%和3.87%,对运动目标的检测速度可达20 fps/s,可满足实时检测的要求.     

Facile Fabrication of Poly(vinyl alcohol)/Polyquaternium-10 (PVA/PQ-10) Anion Exchange Membrane with Semi-Interpenetrating Network

Anion exchange membranes (AEMs) are one of the core components of AEM fuel cells. A series of poly(vinyl alcohol)/polyquaternium-10 (PVA/PQ-10) AEMs with semi-interpenetrating networks (s-IPNs) are prepared by a simple solution-casting method using glutaraldehyde (GA) as a cross-linking agent. Subsequently, the prepared PVA/PQ-10 cross-linked membranes are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, mechanical analysis, water uptake and swelling ratio tests, ion exchange capacity (IEC) tests, ionic conductivity measurements, and oxidative/alkaline stability tests. The effects of the mass ratio of PVA and PQ-10 and the amount of cross-linking agent GA on the performance of the PVA/PQ-10 cross-linked membranes are systematically explored. The results show that the cross-linked PVA/PQ-10 AEMs have high IEC and low water uptake and swelling ratio, and its maximum ionic conductivity can reach 79.37 mS cm^–1 at 80 °C. In addition, the PVA/PQ-10 cross-linked membrane has good oxidative and alkaline stability under optimal preparation conditions. These results may provide valuable insights toward more effective scheme designs and new, simple preparation methods for AEMs with s-IPN structures.