人脸检测的继承式集成学习方法

基于"遗传+变异"模式,提出继承式集成学习方法框架,它可以训练出四种不同形式的层叠分类器。除了基于"无遗传"模式的基本层叠分类器与基于"全部遗传"模式的嵌入式层叠分类器两种传统方法之外,还有基于"部分遗传+部分变异"模式的特征继承层叠分类器与弱分类器继承层叠分类器。虽然后两种层叠分类器都有一定的继承代价,但是其拟合性更好,可以更好地均衡收敛速度和扩展性能,其综合性能优于传统方法。基于RAB、GAB算法与LUT弱分类器的正面直立人脸检测实验结果表明了新的继承式集成学习方法的有效性。     

复杂背景下弱小目标的检测*

复杂背景下低信噪比弱小目标的检测是当今目标捡测的一个热点课题。为了检测到弱小目标,首先对图像进行复杂背景抑制,以达到抑制背景、提高信噪比的目的,然后比较三种方法的背景抑制能力,最后对抑制效果好的图像进行图像分割来进行弱小目标检测。     

基于奇异值分解算法的瑞雷波相速度反演研究

进行瑞雷波相速度反演时,在对其频散曲线的线性化过程中,因误差的引入会导致系数矩阵奇异或近似奇异。为解决此问题,利用奇异值分解算法进行瑞雷波相速度反演,可提高低速软弱夹层的反演精度和可靠性;反演时引入权重矩阵提高了数据分辨率;采用自适应修改阻尼因子以提高迭代效果并协调分辨率与解的关系。实测资料试算结果表明,利用奇异值分解算法对瑞雷波相速度进行反演,不但具有稳定性好、精度高、分辨能力强的特点,而且能自动分层和反演地层参数。     

协整检验在SAS／ETS中的实现

SAS系统是大型集成的应用信息系统,拥有完备的数据访问、数据管理、数据分析和数据呈现功能。利用SAS的ETS模块做协整检验,不仅可以充分实现模型的设定和多样的估计,而且可以集成其他模块完善输出结果。     

一种基于方差的图像边缘检测算法

鉴于传统微分边缘检测算法不适用于识别图像中与背景灰度区别较小的弱边缘,提出了基于方差的图像边缘检测算法,并介绍了其原理和算法实现过程。实验表明,该算法能较好检测出背景灰度区别较小的物体边缘,并有一定的抗噪能力,提高了图像边缘检测效果。     

Generic Transformation from Weakly to Strongly Unforgeable Signatures

Current techniques for transforming unforgeable signature schemes （the forged message has never been signed） to strongly unforgeable ones （the forged message could have been signed） require supplementary components to be added onto the original key pairs of the schemes. In addition, some of them can only be applied to a certain type of signature schemes. In this paper, we propose a new generic transformation technique which converts any unforgeable signature scheme into a strongly unforgeable one without modifying any component in the original key pair. This makes our technique especially compatible for practical use. Our technique is based on strong one-time signature schemes. We show that they can be constructed efficiently from any one-time signature scheme that is based on one-way functions. The performance of our technique also compares favorably with that of current ones. Besides, it is shown in this paper that our transformation can further be applied to schemes satisfying only a weak variant of unforgeability without any further modification. Furthermore, our technique can also be used for constructing strongly unforgeable signature schemes in other cryptographic settings which include certificateless signature, identity-based signature, and several others. To the best of our knowledge, similar extent of versatility is not known to be supported by any of those comparable techniques. Finally and of independent interest, we show that our generic transformation technique can be modified to an on-line/off-line signature scheme, which possesses a very efficient signing process.     

一种新的改进AdaBoost弱分类器训练算法

AdaBoost是机器学习中比较流行的分类算法.通过研究弱分类器的特性,提出了两种新的弱分类器的阈值和偏置计算方法,二者可以使弱分类器识别率大于50%,从而保证在弱分类器达到一定数目的情况下,AdaBoost训练收敛.对两种阈值和偏置计算方法的仿真实验结果表明,在错分率降可接受的范围内,二者均使用较少的弱分类器便可获得高识别率的强分类器.     

Stability of solutions of stochastic functional-differential equations with poisson switchings and entire prehistory

The Markov properties of the solutions of Ito-Skorokhod stochastic functional-differential equations (SFDEs) with entire prehistory are considered, the concept of a weak infinitesimal operator is introduced for a Markov process that is a solution of an SFDE, and the strong solution of the SFDE is analyzed for stability. Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 123–134, January–February 2009.     

传感器弱信号的放大应用电路

介绍了几种弱信号放大的基本方法和一些典型的应用电路。     

Weak-link behavior in superconducting thick films

The surface impedance of melt-processed thick films of YBa₂Cu₃O_7–x on yttria-stabilized zirconia substrates has been measured as a function of temperature over the frequency range 9–18 GHz using an endwall replacement technique. The temperature dependence of both the penetration depth and the surface resistance of thisp-type cuprate system can be described within a two-gap weak-link model. The surface resistance scaled to 10 GHz by the observedf ² frequency dependence gives a value of 1.8 m at 77 K, which compares favorably with the lowest reported values for thick films of this material at microwave frequencies. Trends in material processing indicate that increasing the grain size would further decrease the surface resistance at microwave frequencies.