一种基于主从机制的认知Ad Hoc网络可靠路由方法

为了解决认知Ad Hoc网络中节点和链接失效问题,提出一种基于主从机制的认知Ad Hoc网络可靠路由构造方法MSMRC。该协议考虑了网络中主用户活动规律,引入链路可靠时长和信道可靠时长的度量来设计主路由和备份路由。当现有路由失效时,通过预先构造的备份路由快速恢复认知用户之间的通信。实验表明,MSMRC协议能够显著降低平均路由开销,而且可以提高网络的数据包投递率和链路修复率,保证了网络端到端通信的服务质量。     

1秒采集的三维头像摄影系统

为了实现高精度、快速度、低成本的三维头像建模,提出一个人体头部的三维摄影系统.该系统能够1 s采集用户的三维信息,3 min内建立照片真实感的三维模型.通过配置多目RGB-Depth相机摄影系统,保证1 s内完成对人体头部的全方位数据采集,进而对所得到的点云数据进行数据增强、配准、表面重建和着色,最终生成高逼真的三维头像模型.     

基于兼容性网格分割的骨骼参数计算

为了解决骨骼参数难以测量的问题,提出一种利用网格分割结果计算参数的方法.首先对骨骼网格模型在提取少量特征点的基础上进行语义分割;然后将分割得到的模板借助基于Laplacian变形的非刚性配准,指导同类骨骼模型实现快速兼容性分割;最后结合网格分割结果及特征点计算出骨骼的主要形态参数.实验结果表明,该方法仅需少量的用户交互就能获得较好的测量效果,结合模板的策略也支持大批量骨骼模型的参数测定.     

基于最大后验概率-马尔科夫随机场的二进制体数据优化

许多三维重建算法的结果以二进制体数据的形式给出,然而直接从中抽取等值面会造成阶梯化、锯齿化等走样现象.为此提出基于最大后验概率?马尔科夫随机场的二进制体数据优化方法.假设目标数据是随机变量并具有马尔科夫性,通过计算其最大后验概率推导了通用的优化公式,以及在常用模型下的优化公式;在此基础上,用户可选择不同的先验模型和观察模型来预测数据最有可能的取值,并将其作为优化结果.实验结果表明,文中方法可用于二进制体数据的可视化,光顺,去噪,修复等.     

双球面投影几何可量测全景模型的构建

针对全景影像难以提供空间度量的问题,提出一种基于双球面投影几何的可量测立体全景模型构建方法.该方法依据球面全景投影关系与多视几何原理,采用对应变换与本质变换求取旋转及平移参数,并推导出双球面核线约束;在此基础上,建立起双球面投影几何的立体全景模型,解决了球面全景的量测问题.实验结果表明,文中方法可使全景影像在真实呈现户外场景的同时,提供满足一定应用需求的量测分析功能.     

Stability analysis and control for switched stochastic delayed systems

This paper investigates almost sure exponential stability and feedback stabilization for switched time‐delay systems with nonlinear stochastic perturbations. The main contributions of this paper are threefold: (i) based on the non‐convolution type multiple Lyapunov functionals and the mathematical induction approach, a mean‐square exponential stability condition for nonlinear stochastic switched systems is first established, such that the obtained average dwell time does not rely on any given decay rate; (ii) by using the method developed in part (i) and the stochastic analysis techniques and limit methods in probability, an almost sure exponential stability criterion for switched delayed systems with nonlinear stochastic uncertainties is presented, and then a state feedback controller for the systems under consideration is designed; and (iii) when certain assumptions are made on the nonlinear stochastic perturbations, the results in this paper are further improved by relaxing some conditions. The effectiveness of the proposed method is demonstrated by three illustrative examples. Copyright © 2015 John Wiley & Sons, Ltd.     

Two general integral inequalities and their applications to stability analysis for systems with time‐varying delay

Integral inequalities have been widely used in stability analysis for systems with time‐varying delay because they directly produce bounds for integral terms with respect to quadratic functions. This paper presents two general integral inequalities from which almost all of the existing integral inequalities can be obtained, such as Jensen inequality, the Wirtinger‐based inequality, the Bessel–Legendre inequality, the Wirtinger‐based double integral inequality, and the auxiliary function‐based integral inequalities. Based on orthogonal polynomials defined in different inner spaces, various concrete single/multiple integral inequalities are obtained. They can produce more accurate bounds with more orthogonal polynomials considered. To show the effectiveness of the new inequalities, their applications to stability analysis for systems with time‐varying delay are demonstrated with two numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.     

Annular ring slot antenna design with reconfigurable polarization

A microstrip‐fed conventional annular ring slot (ARS) antenna with linear polarization (LP) is initially studied. To generate two orthogonal degenerate modes for circular polarization (CP) radiations, two identical meandering perturbation slots (MPS) are symmetrically loaded into the ARS. By further incorporating a PIN diode switch across each MPS, the proposed antenna can switch between left‐hand CP (LHCP), right‐hand CP (RHCP), and LP. All three polarizations have shown good impedance bandwidth and broad CP bandwidth that can satisfy the wireless local area network (WLAN) 2.4‐GHz operating band (2400–2480 MHz). Furthermore, desirable gains of 1.8–2.0 dBi and 2.40–2.84 dBic are also exhibited at LP and LHCP/RHCP, respectively. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:110–120, 2016.     

An SNN-Based Semantic Role Labeling Model with Its Network Parameters Optimized Using an Improved PSO Algorithm

Semantic role labeling (SRL) is a fundamental task in natural language processing to find a sentence-level semantic representation. The semantic role labeling procedure can be viewed as a process of competition between many order parameters, in which the strongest order parameter will win by competition and the desired pattern will be recognized. To realize the above-mentioned integrative SRL, we use synergetic neural network (SNN). Since the network parameters of SNN directly influence the synergetic recognition performance, it is important to optimize the parameters. In this paper, we propose an improved particle swarm optimization (PSO) algorithm based on log-linear model and use it to effectively determine the network parameters. Our contributions are two-folds: firstly, a log-linear model is introduced to PSO algorithm which can effectively make use of the advantages of a variety of different knowledge sources, and enhance the decision making ability of the model. Secondly, we propose an improved SNN model based on the improved PSO and show its effectiveness in the SRL task. The experimental results show that the proposed model has a higher performance for semantic role labeling with more powerful global exploration ability and faster convergence speed, and indicate that the proposed model has a promising future for other natural language processing tasks.