基于数学结构的蛋白质二维数字表达及其应用研究

本文提出了蛋白质的一种二维数字表达,该表达考虑了组成蛋白质的核苷酸在DNA双螺旋结构中的对称性和密码子当中的核苷酸组成规律,使之与生物学意义相符合。Cosic’s 的一维共鸣识别方法是一种数学物理模型,它使用信号处理的方法识别蛋白质序列当中包含的信息。根据本文提出的蛋白质二维数字表达,并结合使用向量序列的傅里叶变换理论,提出了高维共鸣识别方法。结果显示,本文提出的二维数字表达和高维共鸣识别在判别双序列的蛋白质相似性问题时也是有效的。     

AAindex数据库中傅里叶方法的多重氨基酸指数选择

波谱学方法研究蛋白质时,蛋白质序列的特征频率与蛋白质的位点、功能、空间结构对应.基于时间序列傅里叶变换的交叉谱原理,本文提出的“一个蛋白质关于多种氨基酸指数的一致谱”能够获取一个或多个蛋白质序列较显著的特征频率,再由特征频率去筛选与之对应的氨基酸指数.该方法与Lazovi(c)的筛选方法和筛选意义不同.结果显示,筛选出的氨基酸指数对应的性质多数与蛋白质的空间结构性质有关.蛋白质特征频率也许是用于特征提取的好方法,氨基酸指数筛选可被看作蛋白质数字表达的一种优化.     

一种基于多阶畸变子模式相似性学习的序列识别方法

序列识别研究对于诸多应用研究领域有重要的意义。在序列识别中,由于多种因素的影响,同一类别标记的序列往往不具有严格的相似性。变化序列相似性描述的尺度对序列的相似性进行描述有利于获得更准确的序列相似性描述结果,为此提出了基于多阶畸变序列子模式的序列识别方法。通过定义序列多阶畸变子模式特征空间及其核变换函数,设计线性开销算法有效实现了序列畸变子模式高维特征向量的计算,进而利用半定规划对多阶畸变序列子模式的核变换矩阵进行优化。基于多阶畸变子模式相似性描述优化结果,支持向量机生成的识别方法比较好地适应了序列之间的不同程度的相似性畸变,而且具有柔性边界特征。本方法在蛋白质基准数据SCOP 1.37 PDB90上进行了实验,普遍提高了该数据集上33个不同家族蛋白质序列的识别结果。     

微博文本的句向量表示及相似度计算方法研究

在Word2vec框架内,针对微博文本的特点,提出采用词向量或高维词库映射计算句向量的方法。以3种算法构造句向量,即采用Word2vec对微博文本进行扩展后以TF-IDF方法表示句向量;将句子中每个词的词向量相加形成句向量;构建高维词库,将句子中的每个词映射到高维词库形成句向量。对比3种训练句向量的方法,选出最适合微博领域的模型。实验结果表明,采用高维词库映射的方法对微博的句向量计算的效果最佳。     

基于支持向量机的生物序列分析

支持向量机是一种比较新的机器学习方法,它满足结构风险最小的要求,并且能够适用于高维的特征空间,因此在生物序列分析中得到了广泛地应用。结合基因序列的特点,提出了一种新的核函数--位置权重子序列核函数。这个核函数融合了基因序列中子序列的组成特征和位置信息,能够比较充分地体现序列特征。将这个核函数用于基因剪接位点的识别分析,得到的结果表明,采用了位置权重子序列核函数的支持向量机能够很好的识别剪接位点,与其它方法相比,取得了更高的识别精度。     

一种基于LLM的高维时间序列数据异常检测方法

以国家重大建设项目稽察中的数据一致性判别问题为应用背景,针对时间序列型高维数据提出了一种基于局部线性映射(Local Linear Mapping,LLM)的数据变换方法,该方法将各高维数据点通过其相邻点的线性重构映射至低维空间,从而很好地保留了高维空间中各数据点与相邻数据点的相关性。基于LLM的映射特性,提出了三种异常指标,并将其应用于面向国家重大建设项目稽察数据一致性判别问题的高维时间序列数据异常检测中。数值计算表明,所提出的方法对时间序列异常检测具有很好的效果,适合于较大规模高维时间序列数据的异常检测应用。     

NAP序列核函数在话者识别中的应用

针对话者识别系统中特征向量不定长和交叉信道干扰等问题,提出一种基于超向量的扰动属性投影(NAP)核函数。该函数是一种新型的序列核函数,使支持向量机能在整体语音序列上分类,移除核函数空间中与话者识别无关的信道子空间信息。仿真实验结果表明,该函数可有效提高支持向量机的分类性能和话者识别系统的识别准确率。     

Cla_Factor:一个基于支持向量机的人类转录因子分类方法

转录因子识别对于理解转录机制起着重要作用,转录因子根据DNA绑定域的结构可以分为四大类.随着数据库中新蛋白序列的快速增加,设计一个高通量、高准确率的分类器来预测新蛋白是否转录因子及其类别是非常重要的,提出了一个基于支持向量机的人类转录因子分类算法Cla_Factor. Cla_Factor使用蛋白域作为向量基来表示蛋白质序列,在此高维向量表示方法下利用支持向量机来对人类转录因子分类.通过对来自于Transfac, Swiss_Prot的数据进行交叉验证测试、推广能力测试,证明了Cla_Factor算法同其他算法相比,具有更高准确率、敏感性、特异性以及推广能力.     

基于线性对数似然核函数的说话人识别

为了提高文本无关的说话人识别系统的性能,提出了基于线性对数似然核函数的说话人识别系统。线性对数似然核函数利用高斯混合模型对频谱特征序列进行压缩;将频谱特征序列之间的相似程度转化为高斯混合模型参数之间的距离;根据距离表达式,利用极化恒等式求得频谱特征序列向高维矢量空间的映射方法;最后,在高维矢量空间,采用支持向量机(SVM)为目标说话人建立模型。在美国国家标准技术署公布的说话人识别数据库上的实验结果表明,所提核函数具有优异的识别性能。     

一种求解高维数据最佳鉴别向量的新算法

针对线性鉴别分析LDA(Linear Discriminant Analysis)方法在高维人脸图像识别领域的应用,提出一种计算最佳鉴别向量的新算法,无需对高维图像数据进行降维预处理,直接计算最佳鉴别向量。算法得到的鉴别向量相互正交,与已有的算法得到的鉴别向量相比,具有更好鉴别性能。在ORL和VALID人脸数据库上的实验结果证明了本算法的有效性。     

基于离散傅里叶不变特征的人脸识别

给出了一种基于离散傅里叶不变特征的人脸识别方法。从连续傅里叶变换出发,讨论连续傅里叶变换情况下的傅里叶变换性质,给出离散傅里叶变换情况下的傅里叶变换性质。依据离散傅里叶变换性质,推导出离散傅里叶变换的不变特征,并将其用于人脸图像识别。人脸识别结果表明方法具有很好的识别能力。     

基于人脸图像的性别识别技术

以原始人脸图像为基础,用灰度拉伸、灰度均衡、中值滤波、图像锐化和图像变换等多种处理方法对人脸图像进行预处理,用分形几何的关联维方法提取人脸图像的特征值,并通过BP网络建立性别识别模型。在此基础上,用上述各种预处理方法对29个未参与建模的人脸图像处理,然后进行性别识别。结果表明,用灰度拉伸和傅立叶变换处理的人脸图像,性别识别效果较好;图像变换比其他处理方法的识别效果好;先对人脸图像作灰度拉伸,然后作傅立叶变换,性别识别效果最佳。     

Single-channel SEMG using wavelet deep belief networks for upper limb motion recognition

Surface electromyography (SEMG) has been widely used in different fields such as human machine interaction and motion recognition. A hybrid classification model based on singular value decomposition (SVD) and wavelet deep belief networks (WDBN) is firstly proposed in this paper, which allows the machine to recognize the single-joint motions of upper limb by using one channel. In this experiment, the three-joint SEMG signals of upper limb are respectively recorded through different two channels, which are employed for subsequent comparison to obtain the best single-channel of each joint. Afterwards, the collected raw signals are enhanced by SVD processing. Wavelet function is applied to replace sigmoid function as activation function for feature learning, and the spectrum signals processed by fast Fourier transform (FFT) are input to WDBN model. The results demonstrate that the recognition rates of three joint movements can be up to 100% by SVD-WDBN method, which is much better than support vector machine (SVM), back propagation (BP) neural network and extreme learning machine (ELM) model. The proposed method makes it more possible to control wearable devices with different single-channel SEMG signals, thereby the work efficiency of smart wearable devices can be improved, as well as the complexity of operations between human and machine can be reduced.     

A Fourier-LDA approach for image recognition

Fourier transform and linear discrimination analysis (LDA) are two commonly used techniques of image processing and recognition. Based on them, we propose a Fourier-LDA approach (FLA) for image recognition. It selects appropriate Fourier frequency bands with favorable linear separability by using a two-dimensional separability judgment. Then it extracts two-dimensional linear discriminative features to perform the classification. Our experimental results on different image data prove that FLA obtains better classification performance than other linear discrimination methods.     

Scale-Free Registrations in 3D: 7 Degrees of Freedom with Fourier Mellin SOFT Transforms

Fourier Mellin SOFT (FMS) as a novel method for global registration of 3D data is presented. It determines the seven degrees of freedom (7-DoF) transformation, i.e., the 6-DoF rigid motion parameters plus 1-DoF scale, between two scans, i.e., two noisy, only partially overlapping views on objects or scenes. It is based on a sequence of the 3D Fourier transform, the Mellin transform and the SO(3) Fourier transform. This combination represents a non-trivial complete 3D extension of the well known Fourier-Mellin registration for 2D images. It is accordingly based on decoupling rotation and scale from translation. First, rotation—which is the main challenge for the extension to 3D data - is tackled with a SO(3) Fourier Transform (SOFT) based on Spherical Harmonics. In a second step, scale is determined via a 3D Mellin transform. Finally, translation is calculated by Phase-Matching. Experiments are presented with simulated data sets for ground truth comparisons and with real world data including object recognition and localization in Magnetic Resonance Tomography (MRT) data, registration of 2.5D RGBD scans from a Microsoft Kinect with a scale-free 3D model generated by Multi-View Vision, and 3D mapping by registration of a sequence of consecutive scans from a low-cost actuated Laser Range Finder. The results show that the method is fast and that it can robustly handle partial overlap, interfering structures, and noise. It is also shown that the method is a very interesting option for 6-DoF registration, i.e., when scale is known.     

Comparisons of a neural network and a nearest-neighbor classifiervia the numeric handprint recognition problem

A comparison is made of two techniques for recognizing numeric handprint characters using a variety of features including 2D fast Fourier transform coefficients, geometrical moments, and topological features. A backpropagation network and a nearest neighbor classifier are evaluated in terms of recognition performance and computational requirements. The results indicate that for complex problems, the neural network performs comparably to the nearest-neighbor classifier while being significantly more cost effective.     

Signal recognition: Fourier transform vs. Hartley transform

The new generic feature representation approach was utilized for Gaussian recognition. Approach consists of using simultaneously two new recognition features: real and imaginary Fourier components with taking into account the covariance between features.

Advanced time–frequency technique, short time Fourier transform was considered.

The recognition effectiveness between the new approach and Hartley based approach was compared. It was shown for Gaussian recognition that Hartley approach is not an optimal and is not even a particular case of the proposed approach. The use of the proposed approach provides an essential effectiveness gain in comparison with Hartley approach.     

基于小波变换和分形维数的车牌汉字识别

提出一种基于小波变换与分形维数的车牌汉字识别方法.对字符图像进行预处理和小波变换,应用改进的微分盒维法计算图像分形盒维值,并构造特征向量,利用支持向量机分类器对字符进行分类与识别.实验结果表明,该方法对模糊字符的识别具有鲁棒性,可提高汉字识别率.