基于小波域隐马尔科夫树模型的图像分割

改进了传统的基于小波域隐马尔科夫树模型的图像分割方法.由于传统方法均为直接选择小波子带系数作为训练特征,不能直接得到像素级分割结果;同时传统方法在后融合方面对所有尺度均采用同一种上下文背景,而忽略不同尺度上初分割类标志图的特点.因此,本文在粗分割阶段首先处理了训练时参数设置的问题,并选取了更能表征纹理的特征,能直接得到像素级分割结果;在多尺度融合阶段,充分利用不同尺度上类标志图的特性,不仅考虑粗尺度信息对融合结果的影响也考虑了细尺度信息对结果的影响.实验表明本文算法的视觉效果好干与本文进行比较的Choi提出的HMTseg以及孙强提出的WD-HMTseg遥感图像分割算法.     

无驱动硅微机械陀螺信号解调的研究

从无驱动硅微机械陀螺的敏感结构原理出发，对它的输出信号特征进行了分析，建立了相应的数学模型，提出使用最小均方差（LMSD）的算法对输出信号进行解调。使用MATLAB的数据处理方法，对仿真转台上得到的波形数据进行数字解调，将得到的结果与实际输入相比较，结果表明采用LMSD算法能够解调出陀螺的俯仰和偏航角速度信号。     

基于邻居节点平均距离的网络覆盖判别模型

在 SITE(信息技术与工程学院)算法基础上,提出了 ADDM(基于邻居节点平均距离的网络覆盖判别模型)算法,通过计算所有邻居节点与本节点的平均距离和交叠区域的圆心角来判别该节点是否为冗余节点。理论分析与仿真实验表明,AD-DM算法较大地改善了 SITE算法,成功解决了 SITE算法没有考虑距离大于感知半径的节点对覆盖冗余贡献的问题,从而用更少的节点实现了区域的覆盖,节省了网络节点的活动数目,延长了网络的生存时间。     

强激光远场焦斑重构算法研究

通过CCD图像采集单元结合传统的列阵相机测量高功率固体激光器的远场焦斑分布,采用图像处理技术的边缘算子提取焦斑的几何中心,提出通过几何中心对心的焦斑嵌套重构算法,解决了光斑饱和时的对心难题,实现了快捷准确测量激光焦斑,为激光器的实时控制提供参考数据。     

柱几何Rayleigh-Taylor不稳定性的数值模拟

给出了柱几何中流体力学方程组及其在数值模拟中采用的计算方法。对二维柱几何Rayleigh-Taylor不稳定性进行数值模拟,在线性阶段与线性理论符合得很好;不稳定性增长进入非线性区域的阈值依赖于界面的位置,并且明显不同于平面情况。     

Steady-state analysis of the long LMS adaptive filter

For the well-known LMS adaptive algorithm no general analytic solutions are available for the steady-state weight-error statistics under stationary stochastic excitation. Only approximate tools have been developed using certain assumptions (like the “independence assumption”) and producing more or less reliable results in practical situations. It is only for the case of a vanishingly small stepsize that such assumptions are not required. There a closed-form solution can be determined for any colouring of the input signal and the additive noise.Here another particular problem is analyzed: the long filter, i.e. a tapped-delay line structure with a large number of taps. For the limiting case of an infinitely long filter, exact closed-form solutions are derived for the steady-state weight-error correlations and the associated “misadjustment”, again valid for any colouring of the input signal and the additive noise, and now also for any stepsize guaranteeing stability.The analysis is based upon a feedback approach, with a forward branch generating the above-mentioned solution for vanishing stepsize and a peculiar feedback branch responsible for higher-order corrections. As in any feedback structure, instability can occur beyond a critical value of the feedback parameter. In our case an experimentally supported maximum stepsize is found, beyond which spontaneous oscillations might occur.     

基于加气站槽车调度的模型建立与算法研究

通过对CNG的发展形势介绍,深入到要研究的具体问题——槽车调度,槽车调度就是加气站母站向子站调度发送槽车。匈牙利算法是用到线性规划上解决最优化最优解的问题。考虑到槽车调度优化的问题的特殊性,因此在匈牙利算法的思想基础上,提出了最大差值法。此方法能更高效率地运算出最优解。     

A vectorial algorithm with finite element method for prediction of powder segregation in metal injection molding

The design of the mold and the choice of the injection parameters for metal injection molding (MIM) is required to maintain homogeneity of the filled mixture. However, powder segregation is unavoidable in MIM because of the significant difference in densities of the metallic powder and the polymer binder. To achieve an effective prediction of segregation effect, a biphasic model based on mixture theory is employed. The viscous behaviors of each phase and the interaction coefficient between the flows of the two phases should be determined. The solution of two coupled Navier–Stokes equations results in a tremendous computation effort. The previous development of an explicit algorithm makes the biphasic simulation much faster than that of the classic methods. However, it is strongly desired to reduce or even eliminate the numerous global solutions for pressure fields at each time step. Hence, a new vectorial algorithm is proposed and developed to perform the simulation only by vectorial operations. It provides the anticipated efficiency in the simulation of biphasic modeling, and the advantage to use the classic elements of equal‐order interpolations. Some results produced by the two algorithms are compared with the experimental values to validate the new vectorial algorithm. Copyright © 2012 John Wiley & Sons, Ltd.     

An optimal energy‐efficient clustering method in wireless sensor networks using multi‐objective genetic algorithm

In this study, an optimal method of clustering homogeneous wireless sensor networks using a multi‐objective two‐nested genetic algorithm is presented. The top level algorithm is a multi‐objective genetic algorithm (GA) whose goal is to obtain clustering schemes in which the network lifetime is optimized for different delay values. The low level GA is used in each cluster in order to get the most efficient topology for data transmission from sensor nodes to the cluster head. The presented clustering method is not restrictive, whereas existing intelligent clustering methods impose certain conditions such as performing two‐tiered clustering. A random deployed model is used to demonstrate the efficiency of the proposed algorithm. In addition, a comparison is made between the presented algorithm other GA‐based clustering methods and the Low Energy Adaptive Clustering Hierarchy protocol. The results obtained indicate that using the proposed method, the network's lifetime would be extended much more than it would be when using the other methods. Copyright © 2011 John Wiley & Sons, Ltd.     

地杂波背景下运动点目标的SAR成像算法

以理想面目标回波作为地杂波的近似，对面目标特征、面目标回波信号及其处理进行了分析，给出了以面目标为背景的运动点目标SAR成像算法，通过具体实例模拟仿真出独立运动点目标的SAR成像图和以面目标为背景的运动点目标SAR成像图。