谐波分析光谱角制图高光谱影像分类

目的 针对光谱角制图(SAM)分类算法对高光谱像元光谱曲线的局部特征和其辐射强度不敏感,而且易受噪声和维数灾难影响,致使分类效率低和精度较差等缺陷,将谐波分析(HA)技术引入到SAM高光谱影像分类中,提出一种基于谐波分析的光谱角制图(HA-SAM)高光谱影像分类算法.方法 利用HA技术将高光谱影像从光谱维变换到能量谱特征维空间,并提取低次谐波分量及特征系数(谐波余项、相位和振幅),用特征系数组成的向量代替光谱向量,对高光谱影像进行SAM分类.结果 将SAM和HA-SAM同时应用于EO-1卫星的Hyperion高光谱影像分类,通过对比和分析,验证了HA-SAM的优越性,再选择AVIRIS(airborne visible infrared imaging spectrometer)高光谱影像对HA-SAM进行验证,结果表明该算法具有较强的普适性.结论 HA-SAM提高了传统SAM高光谱影像分类的效率和精度,而且适用性较强具有良好的应用前景.     

无线传感器网络分簇路由节能研究

在大规模传感和环境监测中,节约能源延长传感器节点生命已成为无线传感器网络最重要的研究课题之一。提供合理的能源消耗和改善无线网络生命周期的传感器网络系统,必须设计一种新的有效的节能方案和节能路由体系。方案采用一种聚类算法减少无线传感器网络的能量消耗,创建一种cluster-tree分簇路由结构的传感器网络。该方案主要目标是做一个理想的分簇分配,减少传感器节点之间的数据传输距离,降低传感器节点能源消耗,延长寿命。实验结果表明,该方案有效地降低了能源消耗从而延长无线传感器网络生命。     

虚拟环境下Web服务动态负载均衡策略改进

为了提高Web服务集群的伸缩性和自动化能力,从虚拟化和负载均衡两方面研究集群系统,对现有负载采集策略做了改进,设计并实现了一种可根据负载值自动控制集群规模的模型XCluster。新模型运行在Xen提供的虚拟化环境中,实时监视宿主机层和虚拟机层的负载状态,随着集群系统总负载的增长,逐渐引入新的虚拟机来扩大集群规模,同时将任务合理分配到各个虚拟机节点上;当总负载下降时,逐渐关闭虚拟机缩小集群规模,释放出来的硬件资源又可以提供给其他集群系统使用。理论分析和实验结果表明,XCluster只需占用很少的网络通信量完成信息收集和命令下达,能够充分利用虚拟机易于管理的优势完成后端节点的调度,并且在任务总量相同的情况下,使用尽可能少的集群节点来执行任务。     

山西冷锋云系的数值模拟研究

利用NCEP再分析资料和CAMS中尺度云分辨模式,对2010-04-20—04-21发生在山西省的大到暴雨、局部强对流天气过程进行了客观模拟,主要得出以下4点结论：①对比2010-04-20T08：00—04-21T08：00的24 h降水预报与实况可见,山西省中南部降水情况与实况值接近,山西省北部降水情况略大于实况值,模拟域中降水量的最大值略小于实况值,雨带分布与实况非常接近。②2010-04-20T13：00—04-20T17：00,云系处于发展阶段,云内含水量和雪含水量呈增加趋势。其中,云水在2010-04-20T17：00,2.5 km处达到最大值0.24 g/kg,顶高为3.5 km,分布在1.2～3.9 km处,雪最大值为0.25 g/kg,位于0℃层上方;雨滴在暖层,雪和云水的增大区对应着雨的增加区,雪和云水是雨滴形成的主要粒子,且雪和云水是降水的主要原因;云系进入消散阶段,至2010-04-21T10：00降水基本结束。③云系在2010-04-20T10：00开始发展,2010-04-20T18：00到达旺盛阶段,随后开始逐渐消散,至2010-04-21T10：00云体基本消散。垂直上升气流的速度多为0.1 m/s,最大为0.5 m/s,符合层状云系的特征。④在8 km以上的区域,雪会通过凝华、雪花与冰晶碰并和冰晶向雪的自动转化等方式增长。其中,凝华增长起主要作用,最高所占比例为100%.在5～8 k m的区域,雪花通过凝华增长;在4～5 km的区域,雪花通过凝华和冰晶向雪的自动转化增长;在3～4 km的区域,雪花通过凝华和结淞增长,凝华增长最高所占比例为100%.     

CC1101无线通信模块的智能开关设计?

为满足智能开关在大型公共建筑物智能用电系统中的功能需要,设计了基于 CC1101无线通信模块的智能开关,介绍了各组成部分的电路原理,利用 STC 单片机全球唯一 ID 研究了一种简单实用的无线组网方法,并详细介绍了电量计量芯片 RN8209G 的校准方法。     

Fault estimation observer design for discrete‐time systems in finite‐frequency domain

This paper proposes a framework of fault estimation observer design in finite‐frequency domain for discrete‐time systems. First, under the multiconstrained idea, a full‐order fault estimation observer in finite‐frequency domain is designed to achieve fault estimation by using the generalized Kalman–Yakubovich–Popov lemma to reduce conservatism generated by the entire frequency domain. Then, a reduced‐order fault estimation observer is constructed, which results in a new fault estimator to realize fault estimation using current output information. Furthermore, by introducing slack variables, improved results on full‐order fault estimation observer and reduced‐order fault estimation observer design with finite‐frequency specifications are obtained such that different Lyapunov matrices can be separately designed for each constraint. Simulation results are presented to illustrate the advantages of the theoretic results obtained. Copyright © 2014 John Wiley & Sons, Ltd.     

A User‐Centric Evaluation Procedure for the Design of Child‐Resistant Medicine Bottles

Recently, people have begun to realize the importance of child‐resistant (CR) medicine packaging. However, most manufacturers and designers have not been able to effectively provide prevention strategies or design criteria to protect consumers. This research proposes a systematic approach to analyze CR packaging design problems and experiments to evaluate the identified design parameters and to generate the most suitable CR medicine packaging design. The design of a CR packaging bottle is used as an example to help explain the development procedure. During the development procedure, user trials, questionnaires, and children's anthropometric data on bottle opening and hand operations are analyzed. Five design parameters, specifically the cap diameter, cap height, bottle height, bottle diameter, and torsion, are identified and used to perform a Taguchi orthogonal array experimental analysis. A computer‐aided design system is also built to help generate the most suitable design alternatives. The results should assist designers in determining the most important CR design parameters and their most suitable combinations for bottle and related CR medicine packaging design.     

Efficient link scheduling with joint power control and successive interference cancellation in wireless networks无线网络中联合功率控制和串行干扰消除的高效链路调度算法

Existing works have addressed the interference mitigation by any two of the three approaches: link scheduling, power control, and successive interference cancellation (SIC). In this paper, we integrate the above approaches to further improve the spectral efficiency of the wireless networks and consider the max-min fairness to guarantee the transmission demand of the worst-case link. We formulate the link scheduling with joint power control and SIC (PCSIC) problem as a mixed-integer non-linear programming (MINLP), which has been proven to be NP-complete. Consequently, we propose an iterative algorithm to tackle the problem by decomposing it into a series of linear subproblems, and then the analysis shows that the algorithm has high complexity in the worst case. In order to reduce the computational complexity, we have further devised a two-stage algorithm with polynomial-time complexity. Numerical results show the performance improvements of our proposed algorithms in terms of the network throughput and power consumption compared with the link scheduling scheme only with SIC.     

有限元法的轴向运动梁的激励功率谱辨识

主要考虑弯曲变形的细长轴向运动梁,可以作为工程中广泛应用在航天器天线、液体输送管道、汽车驱动带、电梯缆索等的简化机构.对轴向运动柔性梁线性微分方程,采用复模态分析方法导出两端简支和固支边界条件下的固有频率方程;采用Ritz法建立轴向运动梁的有限单元法模型.基于该模型在多种边界条件下进行梁的横向振动分析,并开展定点激励下激励功率谱的辨识.仿真结果表明,与传统的Galerkin截断方法相比.有限元方法能够克服分析方法的建模困难,对复杂边界梁进行有效的分析,对激励的功率谱能够有效地辨识.     

A B-spline curve extension algorithmB 样条曲线延伸算法

B-spline curve extension is an important operation in computer aided design systems. In this paper, we present a new extension algorithm for B-spline curves. The algorithm uses curve unclamping to generate a uniform B-spline curve segment from the original curve and gradually extends the segment to pass through every target point. Algorithms of uniform B-spline curves are used such that our algorithm has a low time cost and can easily handle arbitrary-order derivative constraints at the target points. Generalization for non-uniform rational B-spline curve extension is also discussed, and examples show the efficiency of our method.