基于递归修正Hough变换域的舰船多尾迹检测方法

针对SAR图像舰船尾迹的图像特征差异大的特点,提出基于递归修正Hough变换域的舰船多尾迹检测方法,即通过Hough变换域最大峰值检测出最明显的尾迹,再去掉Hough变换域最大峰以突出次大峰来检测第二条尾迹,由此递归修正Hough变换域多峰结构,直到检测完高于设定阈值的尾迹,从而实现线段对比度与宽度不同的舰船多尾迹检测。SAR图像多尾迹检测实验表明,该方法能有效检测具有图像特征差异的多直线尾迹。

基于修正最小和的简化差分域LDPC译码算法

在深刻分析差分域LDPC译码算法的基础上,提出了基于修正最小和的简化差分域LDPC译码算法。仿真结果表明,在加性高斯白噪声信道环境下,BPSK调制时,提出的译码算法在极大地降低计算复杂度的情况下,性能明显优于对数域的最小和算法并且相比对数域置信算法和差分域译码算法几乎没有性能损失。

符号几何规划及其可行域修正算法

本文脱离了影响较广泛的文献１、２的思路，不依赖反向几何规划，直接讨论符号几何规划，不增变量个数和约束个数。利用集约化思想构造了一个可行城修正算法。本文还对文献２中的一个疏漏作了修改。

一种精确确定电压暂降凹陷域的算法

提出一种基于节点阻抗矩阵确定电压暂降凹陷域的算法,根据电压暂降幅值与传输线故障距离的解析关系式,计算得到各种短路故障情况下各电压限值对应的临界故障点。对任意给定网络参数的电力系统,可确定各种短路故障情况下不同电压限值对应的电压暂降凹陷域。并在此基础上考虑电压暂降持续时间、相位跳变等因素,对电压暂降凹陷域进行修正,从而更加精确地确定凹陷域。利用该算法对IEEE 39节点标准测试系统进行凹陷域分析,并与传统故障点法得到的结果进行比较,验证了算法的精确性和实用性。

智能变电站IEEE1588以太网交换机故障案例复现测试及分析

为解决和预防智能变电站IEEE1588交换机在特定网络环境下运行可能会带来的潜在风险,针对智能变电站IEEE1588交换机运行的网络拓扑结构,给出了一种逐级隔离的故障分析方法。通过某智能变电站IEEE1588交换机的具体应用故障案例,对故障现象进行离线的复现与分析,总结出了故障产生原因并给出了整改建议。案例分析表明,通过逐级隔离的分析方法,可以快速地进行故障分析和定位,通过对故障现象的复现,可有效地进行故障原因分析,从而得出相应的解决方案。

Modified method for extraction of watershed boundary with digital elevation modeling

Boundary extraction of watershed is an important step in forest landscape research. The boundary of the upriver wa-tershed of the Hunhe River in the sub-alpine Qingyuan County of eastern Liaoning Province, China was extracted by digital elevation modeling (DEM) data in ArcInfo8.1. Remote sensing image of the corresponding region was applied to help modify its copy according to Enhanced Thematic Mapper (ETM) image抯 profuse geomorphological structure information. Both the DEM-dependent boundary and modified copy were overlapped with county map and drainage network map to visually check the effects of result. Overlap of county map suggested a nice extraction of the boundary line since the two layers matched precisely, which indicated the DEM-dependent boundary by program was effective and precise. Further upload of drainage network showed discrepancies between the boundary and the drainage network. Altogether, there were three sections of the extraction result that needed to correct. Compared with this extraction boundary, the modified boundary had a better match to the drainage network as well as to the county map. Comprehensive analysis demonstrated that the program extraction has generally fine precision in position and excels the digitized result by hand. The errors of the DEM-dependant extraction are due to the fact that it is difficult for program to recognize sections of complex landform especially altered by human activities, but these errors are discernable and adjustable because the spatial resolution of ETM image is less than that of DEM. This study result proved that application of remote sensing information could help obtain better result when DEM method is used in extraction of watershed boundary.

结合稳像补帧与VIBE算法的抖动视频前景目标提取方法

在动态场景下进行目标检测与跟踪处理时,提取的前景目标往往会因受到背景抖动干扰而出现目标误判、轮廓不完整等问题,为此提出结合稳像与补帧、VIBE算法与连通域修正的抖动视频前景目标提取方法。首先利用ORB对相邻两帧图像进行特征匹配,使用RANSAC剔除误匹配点,以运动目标为中心调整图像边距,裁剪与修补不重合的部分,通过统计法求相邻两帧的偏移均值,完成视频稳像处理;其次利用稠密光流法计算相邻两帧图像的位移,通过位置重映射生成中间帧,实现视频补帧;然后将VIBE算法增加形态学处理与连通域修正,结合Canny算子进行边缘检测,增加目标轮廓的完整性;最后使用视频实例进行测试,与其他视频目标提取算法进行比较分析,精度、召回率至少提高10%,漏检率、错分率至少降低15%。实验结果表明,所提方法能有效去除抖动带来的影响,提取的目标完整性较高。

Determination of fractional energy loss of waves in nearshore waters using an improved high-order Boussinesq-type model

Fractional energy losses of waves due to wave breaking when passing over a submerged bar are studied systematically using a modified numerical code that is based on the high-order Boussinesq-type equations.The model is first tested by the additional experimental data,and the model's capability of simulating the wave transformation over both gentle slope and steep slope is demonstrated.Then,the model's breaking index is replaced and tested.The new breaking index,which is optimized from the several breaking indices,is not sensitive to the spatial grid length and includes the bottom slopes.Numerical tests show that the modified model with the new breaking index is more stable and efficient for the shallow-water wave breaking.Finally,the modified model is used to study the fractional energy losses for the regular waves propagating and breaking over a submerged bar.Our results have revealed that how the nonlinearity and the dispersion of the incident waves as well as the dimensionless bar height(normalized by water depth) dominate the fractional energy losses.It is also found that the bar slope(limited to gentle slopes that less than 1:10) and the dimensionless bar length(normalized by incident wave length) have negligible effects on the fractional energy losses.

电子束光刻研制高分辨X射线波带片透镜最新进展

首先综述了当前X射线透镜的分辨率和效率的水平,预测并讨论了发展我国波带片透镜、赶超国际先进水平的技术路径图。在原有100 nm分辨率波带片和会聚透镜工艺基础上,综述了电子束光刻结合金电镀进一步发展30~70 nm分辨率的X射线波带片的最新进展。在研发30 nm分辨率的波带片中,电子束光刻中的邻近效应严重限制了波带高宽比,而现有商业软件(基于蒙特卡罗模型和显影动力学)的邻近效应修正在同时处理从微米到30 nm的各种图形时效果甚微。为此,本团队针对70 nm分辨率的硬X射线波带片采用了图形修正法,实现了20:1的波带高宽比,针对50 nm分辨率的硬X射线波带片采用了分区域修正法,获得了15:1的波带高宽比;30 nm波带片透镜的金属化摒弃了传统的直流电镀工艺,采用脉冲金电镀,实现了金环均匀电沉积,成功研制了30 nm分辨率的软X射线波带片透镜和30~100 nm的大高宽比分辨率测试卡。所有研制的波带片透镜在上海同步辐射装置得到了X射线光学成像验证。