ECG databases for biometric systems: A systematic review

Computer-based biometric systems (CBBSs) individual recognition are expert and intelligent systems that are gaining increasing interest in many areas, such as securing financial systems, telecommunications and healthcare applications. The electrocardiogram (ECG) has been used as biometric feature for its low circumvention, large acceptability and uniqueness, thus being at the basis of several CBBSs. As ECG databases collected for clinical applications are not adequate for biometric applications, we have assisted to the development of other repositories of ECG, each one different from the others and highlighting certain issues of ECG-based biometric recognition. Through a systematic framework presented here, we quantitative analyse, evaluate and compare the acquisition hardware and the acquisition protocols of ECG databases available in literature and suited to develop CBBSs. Although the most recent ones, namely CYBHI and UofTDB, result the best for the acquisition hardware and the acquisition protocols, respectively, our survey shows that none is exhaustive for developing a robust and general enough CBBSs. The analysis also highlights the current lack of standardization in this field and the difficulty of performing an effective benchmarking activity. Since a publicly available database is essential for the research community in ECG-based CBBS to correctly assess the performance of existing algorithms or even commercial expert systems, we also discuss here the main features that an “optimal” repository for the intelligent application at hand.     

Searching biosignal databases by content and context: Research Oriented Integration System for ECG Signals (ROISES)

Technological advances in textile, biosensor and electrocardiography domain induced the wide spread use of bio-signal acquisition devices leading to the generation of massive bio-signal datasets. Among the most popular bio-signals, electrocardiogram (ECG) possesses the longest tradition in bio-signal monitoring and recording, being a strong and relatively robust signal. As research resources are fostered, research community promotes the need to extract new knowledge from bio-signals towards the adoption of new medical procedures. However, integrated access, query and management of ECGs are impeded by the diversity and heterogeneity of bio-signal storage data formats. In this scope, the proposed work introduces a new methodology for the unified access to bio-signal databases and the accompanying metadata. It allows decoupling information retrieval from actual underlying datasource structures and enables transparent content and context based searching from multiple data resources. Our approach is based on the definition of an interactive global ontology which manipulates the similarities and the differences of the underlying sources to either establish similarity mappings or enrich its terminological structure. We also introduce ROISES (Research Oriented Integration System for ECG Signals), for the definition of complex content based queries against the diverse bio-signal data sources.     

基于USB数据采集便携式心电监护仪的设计

主要针对人体心电信号微弱,易干扰,不易放大的特点,设计了心电信号采集放大的前端电路,并以此为基础进行模数转换,利用USB接口实现数据的PC上传,并对采集到心电信号数据进行分析和处理,同时存储、回显心电波形。设计了基于MFC可视化的上位机软件,具有简单,易用的特性。系统电路具有小型化,模块化,低功耗的特点,适用于家庭便携式的心电监。     

Development and Validation of Team Creativity Measures: A Complex Systems Perspective

Without formalizing the team creativity (TC) concept with reliable and valid measurement, it is difficult to conduct rigorous research to help teams generate creative ideas and problem solving at a high level, of good quality and great value. The one‐sidedness and lack of depth of existing research on team creativity leads to the limited reliability and validity of team creativity measurements. In order to solve these problems, we introduce the complex system theory and develop the TC Scale with nine items for team creativity from three dimensions: team creative thinking, team creative action and team creative outcome. The data is collected from three distinct positions of respondents (managers, team leaders and senior staff) in 183 creative teams. The results of reliability measures, exploratory factor analysis and confirmatory factor analysis strongly support our scale. Further, we test the correlation between team trust and team creativity to establish its predictive validity and make a further verification on the scale structure through second‐order confirmatory factor analysis. Finally, we discuss the implications for research and practice.     

可佩戴式远程心电采集终端的设计与实现

心电数据是诊断人体心脏状态的重要指标,在互联网大数据时代,远程医疗已成为一种趋势。为解决传统心电采集移动性和远程传输问题,而研制出一款可佩戴式远程心电采集终端。它由心电采集模块ADS1198、中央处理模块STM32、显示OLED液晶模块、USB模块、4G模块构成。能实时采集人体心电信号,并进行滤波处理,再通过OLED液晶模块大致显示心电波形。该设备具有通过USB模块传输数据至电脑实行近程心电数据管理或4G模块传输数据至医院监听端实现远程心电接收的功能。其体积为,重量仅为50g,工作电流仅为12.8mA。设备体积小巧,功耗低,便于佩戴,能采集医院分析病理的标准12导联心电数据,适用于在家庭中使用。     

Towards depth estimation in a single aerial image

ABSTRACT

Nowadays, depth estimation from a single image is a task that has been successfully addressed by Convolutional Neural Network (CNN) architectures. In this regard, several authors have taken advantage of depth datasets publicly available to the scientific community to train their CNN-based methods. From a project of Karlsruhe Institute of Technology and Toyota Technological Institute at Chicago has emerged KITTI (acronym derived from the institutions' names) as one of the most popular public datasets providing depth estimates associated to RGB (Red, Green, Blue) images. Regarding the depth data in KITTI and typically in many other datasets, these include monocular or stereo RGB images associated with depth images obtained via laser, stereo cameras or a combination of both. These images and depth data have been collected by driving around outdoor urban environments with cameras looking forward to the horizon. In contrast, in this work, we are interested in CNN-based depth estimation in a single aerial image for which depth datasets are not available. In addition, popular CNN architectures for depth estimation in a single-image struggle to estimate depth in aerial scenes due to the fact that the camera angle and object appearance in aerial imagery are significantly different. Nevertheless, we propose to harvest the depth information available in KITTI in order to tackle the problem of depth estimation in a single aerial image. To this end, our approach is a two-step methodology based on patch processing that is later used as input for a set of proposed CNN architectures. Our results indicate that this approach is promising, and those datasets such as KITTI may indeed be exploited in other domains, especially where the data acquisition may be expensive or difficult to be carried out such as for aerial scenes.     

便携式无线心电采集装置的研究及实现

在对人体心电信号研究的基础上,设计实现了便携式无线心电采集装置。首先设计搭建了心电采集的信号调理电路,其中包括前置放大电路、右腿驱动电路、屏蔽驱动电路以及滤波电路等;然后在此基础上应用无线单片机nRF9E5来实现所采集心电数据的无线收发;为了无线数据传输的准确可靠,制定了通信协议并采取了数据校验措施,同时进行了系统的软件设计;最后对装置进行了测试,试验结果表明所设计方案是可行的和有效的。     

可穿戴心电信号采集与分析系统的设计与实现

针对传统心电采集设备的移动限制性以及佩戴的不舒适性,根据可穿戴计算特点,设计并实现了穿戴式心电采集与分析系统。系统采用自主研发的12/单导联心电采集模块进行心电信号采集,数据可存于采集设备或经3G网络传输到服务器端,同时所开发的软件可对心电图进行辅助病情分析,实现对佩戴人的心电监护。还研究并制作了插入式电极和织物电极,并通过二者的结合提高了采集心电信号的质量。实际佩戴和使用结果表明,使用插入式织物电极的可穿戴式心电采集设备具有良好的舒适性,心电信号波形的质量能够达到临床监控的要求。     

基于心电脉搏特征的视觉疲劳状态识别

为从生物医学信号角度检测和评估视觉疲劳，模拟VDT作业环境，对35位健康被试者进行1.5 h的VDT疲劳实验。使用MP425数据采集卡和LabVIEW构成的数据采集系统同步采集心电(ECG)和脉搏波信号，经信号预处理分析后，提取实验前后的ECG和脉搏波信号特征。研究结果表明，ECG和脉搏波信号特征在实验前后有较大变化，采用支持向量机法对实验前后的ECG脉搏组合特征进行分类，正确率可达100%。     

Post-processing in wireless sensor networks: Benchmarking sensor trace files for in-network data aggregation

Wireless sensor network research usually focuses on the reliable and efficient collection of data. In this paper we target on the next step in the lifetime of traces: we aim at investigating and evaluating, by qualitative and quantitative means, data repositories of already collected measurements. Concerning the collected datasets, several important topics arise like the need of exchanging traces between researchers using a common representation of the traces and the need for common classification of the traces based on a commonly agreed set of statistical characteristics for in retrospect utilization. In order to qualitatively address these issues, we propose the use of a novel set of metrics focusing on the in-network data-aggregation problem class. These metrics enable reliable evaluation of algorithms using the same benchmark traces (both in average cases and “stressful” setups) removing the need for running algorithms in a real testbed, at least in the initial development stage. We present the results of our research as a first approach for addressing this problem, and in order to confirm our method, we characterized several traces with the proposed metrics. We validate the metrics by predicting the performance of three data-aggregation schemes using the available traces and checking the results by actually running the algorithms.     

基于DSP数字心电图机的设计

介绍12导联数字心电图机研制开发,采用双CPU架构,包括数字信号处理TMS320F206和微控制器AT89C55.该仪器利用数字信号处理器TMS320F206PZ实现实时对心电信号进行滤波和心电参数计算;热敏打印心电图形和检测结果;存储病人的心电数据,心电图形的回放打印,与PC机进行数据通主,建立病人的心电数据库,进一步研究分析.     

Collaborative data visualization for Earth Sciences with the OptIPuter

Collaborative visualization of large-scale datasets across geographically distributed sites is becoming increasingly important for Earth Sciences. Not only does it enhance our understanding of the geological systems, but also enables near-real-time scientific data acquisition and exploration across distant locations. While such a collaborative environment is feasible with advanced optical networks and resource sharing in the form of Grid, many technical challenges remain: (1) on-demand discovery, selection and configuration of supporting end and network resources; (2) construction of applications on heterogeneous, distributed environments; and (3) use of novel exotic transport protocols to achieve high performance. To address these issues, we describe the multi-layered OptIPuter middleware technologies, including simple resource abstractions, dynamic network provisioning, and novel data transport services. In this paper, we present an evaluation of the first integrated prototype of the OptIPuter system software recently demonstrated at iGrid 2005, which successfully supports real-time collaborative visualizations of 3D multi-gigabyte earth science datasets.     

Raw data extraction from electrocardiograms with Portable Document Format

During the last two decades there has been a thorough research and development of standards and protocols in order to cope with different electrocardiogram formats from heterogeneous acquisition systems. Despite the efforts of public and private consortiums on creating a standardized electrocardiogram (ECG) storage format, there is still not a single one. Indeed, there is also the necessity of access to raw data of the ECGs previously acquired. Most of these documents have been saved as Adobe PDF files, since for medical staff it is an easy format for later visualization. However, this format presents difficulties when trying to access original raw data for subsequent studies and signal analysis. In this manner, this paper presents an application that obtains plain numerical data from ECG files stored with PDF format. Data can also be exported to one of the most common file formats in existence, to be easily accessed thereafter.     

基于ICA的胎儿心电提取系统

设计并实现了一种基于母体腹部表皮电极的胎儿心电提取系统。系统由硬件采集电路和分析软件两部分组成。硬件模块包含8路心电放大器（可扩展）、模拟滤波器和A／D转换电路;软件模块包含多通道数据采集和存储控制、数字滤波、ICA提取算法以及输入、输出波形的实时显示和回放等子模块。通过临床数据和实测仿真数据验证,本系统能有效地从母体心电中分离出胎儿心电,相应的软、硬件模块也均能够满足设计要求。实验表明,设计的胎儿心电系统具有较高的临床价值,同时也进一步验证了ICA算法应用于胎儿心电获取的可行性。最后,说明了本系统与相关系统对比具有的优势,并且提出了系统的优化方向和应用前景。     

基于 STM32 处理器的手机监控心电的设计

传统的心电采集系统操作平台基于有线装置,与现有的个人通信终端(如移动电话、便捷式电脑)不兼容,且存在不灵活、价格昂贵、操作复杂、连续运行不稳定等缺点。针对上述问题,本作品拟设计以可穿戴式心电采集系统为设计主题,通过 STM32 对心电数据进行采集与处理,实现远程监控心电信号,并允许多户同时链接。同时,通过联合使用互联网,可实现在医院等场所进行长期稳定的心电数据监控,为医疗监护提供有利的帮助。     

Understanding the role of behavioural integration in ISD teams: an extension of transactive memory systems concept

The transactive memory system (TMS) has been considered as one critical element for effective teamwork. However, viewing TMS as a second‐order construct that mixes cognitive (specialty and credibility) and behavioural (coordination) components leads to confusion and increases the difficulty in interpreting study results. This study follows the concept proposed by one recent study and attempts to distinguish between behavioural and cognitive components. Furthermore, drawing on the need for diverse members to be integrated behaviourally, we also attempt to extend the TMS research stream by proposing a more comprehensive behavioural component of TMS. We argue that to obtain better teamwork outcomes, information system development (ISD) team members need to integrate the expertise possessed by each individual, make decisions jointly and interlink all individual actions. In light of this, our study aims to replace coordination with team behavioural integration, a more comprehensive behavioural consequence of cognition and explore the critical role of behavioural integration in ISD teams by understanding its impact on ISD teamwork project team performance. The study result, based on data collected from 205 information system project managers, supports our hypotheses that expertise specialty, credibility and their interaction positively affect team behavioural integration. This, in turn, leads to enhanced project team performance.     

Why is Your Team More Creative Than Mine? The Influence of Shared Mental Models on Intra‐group Conflict,Team Creativity and Effectiveness

In competitive and dynamic contexts team members need to be creative to ensure that teams achieve high levels of performance and feel satisfied with their work. At the same time, team members need to have a shared understanding regarding relevant aspects related to task accomplishment and team interaction. In this study we investigate the mediating mechanisms of intra‐group conflict and creativity in the relationship between shared mental models and team effectiveness (team performance and satisfaction). We tested our model in a sample of 161 teams (735 individuals) performing in a management simulation. We collected data at three time points. Our results suggest that high shared mental models are related to low levels of intra‐group conflict, foster creativity, and in turn improve team performance and satisfaction. These findings contribute to a scarce thematic – the relationship between shared mental models and creativity – emphasizing the importance of a shared understanding for creativity and team effectiveness.     

An automated data extraction system from 12 lead ECG images

A software based normalized ECG data acquisition system is developed for both normal and abnormal ECG records. This system can transfer wave data recorded on paper to the digital time database. A flatbed scanner is used to form an image database of each 12 lead ECG signal. These TIF formatted gray tone images are then converted into two tone binary images with the help of histogram analysis. Smearing runlength technique is used to remove the vertical and horizontal line segments of graphical papers. Thinning algorithm is applied to each image to obtain the skeleton (1 pixel representation) of each image, which is essential to avoid excess data points in the database. After extracting pixel to pixel co-ordinate information of images of each of the signal of 12 lead ECG records, the data are sorted to regenerate the signal. From standard deviation of the database a graphical analysis is performed to examine the consistency of our database.     

无线体域网节点数据压缩节能方法

无线体域网(WBAN)节点通常采用电池供电,能量有限且不易频繁更换.为降低节点能耗,提出了一种数据压缩节能方法,采用稀疏表示分类算法识别正常信号,运用压缩感知(CS)理论进行信号压缩采样,将压缩信号发送至基站并进行重构.对WBAN节点采集的心电图信号进行仿真分析,结果表明:心电图信号经压缩后,具有较好的识别与重构性能,在确保数据传输精度前提下,减少了数据采集量和传输量,有效地降低了WBAN节点能耗.