Nanofiber‐Reinforced Silver Nanowires Network as a Robust,Ultrathin, and Conformable Epidermal Electrode for Ambulatory Monitoring of Physiological Signals

Extremely soft and thin electrodes with high skin conformability have potential applications in wearable devices for personal healthcare. Here, a submicrometer thick, highly robust, and conformable nanonetwork epidermal electrode (NEE) is reported. Electrospinning of polyamide nanofibers and electrospraying of silver nanowires are simultaneously performed to form a homogeneously convoluted network in a nonwoven way. For a 125 nm thick NEE, a low sheet resistance of ≈4 Ω sq^?1 with an optical transmittance of ≈82% is achieved. Due to the nanofiber‐based scaffold that undertakes most of the stress during deformation, the electric resistance of the NEE shows very little variation; less than 1.2% after 50 000 bending cycles. The NEE can form a fully conformal contact to human skin without additional adhesives, and the NEE shows a contact impedance that is over 50% lower than what is found in commercial gel electrodes. Due to conformal contact even under deformation, the NEE proves to be a stable, robust, and comfortable approach for measuring electrocardiogram signals, especially when a subject is in motion. These features make the NEE promising for use in the ambulatory measurement of physiological signals for healthcare applications.     

ECG biometric authentication based on non-fiducial approach using kernel methods

Identity recognition faces several challenges especially in extracting an individual's unique features from biometric modalities and pattern classifications. Electrocardiogram (ECG) waveforms, for instance, have unique identity properties for human recognition, and their signals are not periodic. At present, in order to generate a significant ECG feature set, non-fiducial methodologies based on an autocorrelation (AC) in conjunction with linear dimension reduction methods are used. This paper proposes a new non-fiducial framework for ECG biometric verification using kernel methods to reduce both high autocorrelation vectors' dimensionality and recognition system after denoising signals of 52 subjects with Discrete Wavelet Transform (DWT). The effects of different dimensionality reduction techniques for use in feature extraction were investigated to evaluate verification performance rates of a multi-class Support Vector Machine (SVM) with the One-Against-All (OAA) approach. The experimental results demonstrated higher test recognition rates of Gaussian OAA SVMs on random unknown ECG data sets with the use of the Kernel Principal Component Analysis (KPCA) as compared to the use of the Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA).     

基于ARM-Linux指纹识别系统的设计

生物识别技术应用越来越广泛,指纹识别技术尤为突出。设计了以ARM9为核心的硬件平台,并进行了嵌入式Linux内核的移植,结合硬件特点,将优化后的指纹识别算法作为应用程序移植到软硬件平台。实验表明,系统运行稳定,算法效率和精确度较高,在嵌入式生物识别技术应用领域有一定的参考价值。     

一种机器人自主思维方法

类人智能一直是人工智能和机器人领域的研究重点,如何完善周边信息及对大数据的获取、处理、存储、信息挖掘更是当前研究热点。文中根据人体生物特征,利用多传感器综合对周边环境进行完整,利用数据降维与稀疏学习的技术完成大数据的处理及信息挖掘,并建立一种机器人自主思维模型。进一步提升了机器人的智能性,使之能对实时环境的空间大数据实行处理,并做出自主性反应,具有更强实用性。     

基于人脸表情变化的身份识别

将人脸表情变化作为一种生物识别特征用于身份识别.首次在三维人脸数据上进行了表情变化的身份信息提取,提出了将表情运动方向和运动距离两种新的特征用于身份识别.针对人类普遍存在的六种表情,采用三种不同的特征,以及五种不同的融合策略进行身份识别.在BU-3 DFE数据库上进行了系统的实验,分析比较了不同表情、不同特征以及不同的融合策略的识别性能.实验结果表明将表情变化作为一种生物识别特征是可接受的,并可作为其他生物识别特征的一种有益补充.     

Common interface for connecting of low profile biometric modules

For improving interoperability and gaining in many more benefits, standard interfaces for connecting modules in Information Technology （IT） are a need. Biometrics is not different from other IT fields. In fact in Biometrics those interfaces are needed at different levels： applications, data interchange, processing modules or sensors. Standardization bodies have already published standards related to data interchange and application programming interfaces （API）, but some others are still missing. Authors present in this paper a first approach for a definition of a common interface for those biometric related modules to be integrated in small and low cost embedded systems. Definition is done at two different levels, leaving open the final implementation, but outlining such implementation with state of the art communication protocols.     

Survey of qualitative traits of European sea bass cultivated in different rearing systems

The purpose of this study was to evaluate the main qualitative traits of European sea bass fattened in farms adopting different rearing techniques (offshore cages, inshore cages, land‐based basins) but fed the same diets in each production cycle, in a three year survey (2006, 2007, 2008). Three farms were chosen for each rearing technique and two sampling sessions of ten fish each were carried out for each rearing cycle. Proximate composition, fatty acid profile, and cholesterol content were evaluated in the fillet of marketable size fish as well as morpho‐biometric parameters and indices. Diets administered in 2008 had higher amounts of lipids, lower proportions of n–3 polyunsaturated fatty acids (PUFA) and higher proportions of n–6 PUFA compared to 2006 and 2007 diets. The chemical and fatty acid composition of the fish fillet was affected by the diet composition: fish fattened in 2008 exhibited statistically higher amounts of fat and cholesterol, lower proportions of n–3 PUFA and higher proportions of n–6 PUFA in comparison with fish cultivated in 2006 and 2007. Fish cultivated in cages, both offshore and inshore cages, exhibited leaner fillets, lower amounts of cholesterol and higher proportions of n–3 PUFA than fish cultivated in basins. Practical applications: In this study we have analyzed the combined effects of feeding and rearing systems of sea bass in a 3‐year survey for the first time. The results showed that feeding is the main factor affecting fish quality as regards both the chemical composition and the fatty acid profile. The partial substitution of fish meal and fish oil with vegetable sources, with the aim of saving the wild fish biomass as well as formulating less expensive diets, strongly alters the fillet composition. We also showed that the rearing system of fish in offshore cages makes it is possible to obtain better quality products.     

基于MRP的可撤销模板设计及其分析

 针对基于生物特征认证系统中的存储及传输安全问题,并且考虑到基于VQ(Vector Quantization)算法声纹认证系统训练数据少,存储空间和训练时间也比较小的优点,在基于VQ算法声纹认证系统的基础上,采用MRP(Multispace Random Projection)提出一种可撤销声纹模板.通过特征点与特征点,特征点与码字之间的距离变换前后保持不变,说明平均量化误差不变,从而证明该方法满足可撤销模板的性能保持性.通过随机矩阵和不定方程的分析证明该方法满足不可逆性,即是安全的.初步实验结果的认证率达96%,说明该方法的有效性.     

基于相位一致性最大响应方向的虹膜识别方法

为了进一步提高虹膜识别的准确性,提出了一种基于相位一致性最大响应方向的虹膜识别方法.该方法对人眼图像进行图像预处理,得到归一化的虹膜图像;然后,提取像素对于相位一致性的最大响应方向作为可区分性特征,并将最大响应方向的序号编码为简单易处理的二进制虹膜代码;最后,通过计算两个虹膜代码之间的加权汉明距离衡量二者的差异,并给出识别结果.实验结果表明,该方法的等错率为0.871 5%,正确识别率为99.851 8%.与经典的虹膜识别方法相比,该方法具有更高的识别准确性.