基于稀疏编码和集成学习的多示例多标记图像分类方法

该文基于稀疏编码和集成学习提出了一种新的多示例多标记图像分类方法。首先,利用训练包中所有示例学习一个字典,根据该字典计算示例的稀疏编码系数;然后基于每个包中所有示例的稀疏编码系数计算包特征向量,从而将多示例多标记问题转化为多标记问题;最后利用多标记分类算法进行求解。为了提高分类器的泛化能力,对多个分类器进行集成。在多示例多标记图像数据集上的实验结果表明所提方法与其它方法相比有更好的性能。     

Novel Direction Findings for Cyclostationary Signals in Impulsive Noise Environments

We consider the problem of direction-of-arrival (DOA) estimation for cyclostationary signals in impulsive noise modeled as a complex symmetric α-stable (SαS) process. Since the DOA estimation based on second-order cyclic statistics degrades seriously in an α-stable distribution noise environment, we define a novel pth-order cyclic correlation by fusing the fractional lower order statistics and second-order cyclic correlation. After briefly introducing the statistical characteristics of pth-order cyclic correlation and building the extended data model, we first propose a novel extended pth-order cyclic MUSIC algorithm (EX-POC-MUSIC) by exploiting both pth-order cyclic correlation and pth-order cyclic conjugate correlation. The algorithm allows us to select desired signals and to ignore interference in the communication system. Second, in order to increase the resolution capabilities and the noise robustness significantly, an improved EX-POC-MUSIC algorithm called the extended pth-order cyclic Root-MUSIC (EX-POC-RMUSIC) algorithm is also presented. This algorithm has all the merits of the EX-POC-MUSIC algorithm, and it is also a fast DOA estimation algorithm because it avoids spatial spectrum searching. Under some conditions, both proposed algorithms are able to handle more sources than the number of sensors. Simulation results strongly verify the effectiveness of the two algorithms.     

河道洪水实时预报模型及在寸滩—螺山河段的应用

采用水力学和水文学相结合的方法，根据河道非恒定流的圣维南方程组，建立了河道洪水相应涨至预报模型和扩散波洪水预报模型，既可预报流量，又可预报水位。在模型的实时校正技术中，采用了具有时变遗忘因子的递推最小二乘实时校正算法，提高了参数实时跟踪能力和辨识精度。相应涨差实时预报模型和扩散波实时预报模型在寸滩－螺山河段上的应用均获得较好的效果。     

污灌污染系统整体数学模型

依据污染物的迁移转化途径，建立了模拟预测迁移型污染物变化的整体数学模型，整体模型由表土层模型、下包气带模型、含水层模型组成，表土层模型为黑箱模型，下包气带模型为一维垂向迁移模型，含水层模型为二维平面迁移模型，子模型之间用流量和污染物浓度耦合·在河北省新河县污灌试验区进行的实例应用中，对求解复杂的含水层模型，采用美国IOWA大学教授陈景仁提出的有限分析法求解，经实测资料验证，整体模型是可靠的，并模拟预测了该区在现状污灌状态下，迁移型重金属As、Cr 6和可降解有机物BOD、COD的变化趋势，及其达标年限     

载荷频率对低碳马氏体钢腐蚀疲劳的影响

研究了恒定载荷和三种频率的动载荷条件下,经淬火及低温回火的两种低碳马氏体钢在25℃,3.5％NaCl水溶液中的裂纹扩展行为。结果表明载荷频率对低碳马氏体钢腐蚀疲劳裂纹扩展的动力学特征影响很大,特别是在K_(max)相似文献   

SLED中熔锥形透镜光纤耦合设计

文章提出一种熔锥形透镜光纤的设计方法,与常用的圆锥形保偏单模光纤相比,熔锥形透镜光纤与超辐射发光二极管(SLED)管芯的耦合效率可由原来的45%提高到60%,工作距离由7 μm达到超过15 μm,且前者的耦合容差远远大于后者.对于新设计的熔锥形透镜光纤,文章还给出了偏移和偏心与耦合效率的关系曲线图.     

Reconstruct azimuth signal and suppress interbeam ambiguities of SPCMB SAR with hybrid filterbank

Conventional Synthetic Aperture Radar （SAR） systems cannot obtain high-resolution and wide-swath illumination area due to the well-known minimum antenna area constraint. Single Phase Center MultiBeam （SPCMB） technique can overcome this limitation by adding spatial sampling through multiple receivers in azimuth direction. Unfortunately, this approach will lead to an increase of azimuth ambiguities （interbeam ambiguities）, because each receive beam＇s mainlobe overlaps with the other ones＇ sidelobes. This paper proves that the front part of SPCMB SAR systems can be considered to be a hybrid filterbank. Therefore, the azimuth signal can be reconstructed and the interbeam ambiguities can be effectively suppressed by a well-designed hybrid filterbank.     

基于DSP便携式数控测井系统的设计

为解决大型数控测井系统体积庞大,测井车本身所能提供的空间有限这一实际情况,提出一种基于DSP的便携式数控测井系统。着重论述系统的整体架构及地面系统中数据处理模块硬件电路的设计,通过CAN总线接口实现系统内部各个模块之间的数据通信,并利用USB接口完成与主机之间的数据交换,同时简要介绍软件设计流程。高性能DSP的使用及数据通信模块的改进．使系统可以满足参数处理实时性的要求,应用于生产测井过程当中。实践证明．该系统具有一定的可靠性及实用性。     

S波段280 W SiC内匹配脉冲功率管

现代雷达和通讯系统要求不断地提高微波功率器件的功率、效率以及带宽.     

频谱拍卖中投标者共谋策略与多频段拍卖中共谋问题的讨论

本文通过对单频段拍卖中共谋问题的研究,从抑制共谋的角度,提出了最优的拍卖机制是第一价格封闭式拍卖,论证了频谱拍卖中投标者的最优共谋策略,给出了拍卖方基于保留价格的应对投标者共谋的对策。在单频段拍卖研究的基础上,进一步将频谱拍卖中的共谋问题引申到多频段拍卖中,讨论了当待售频段之间具有互补性和替代性时的共谋情况。