Electronic nose for space program applications

The ability to monitor air contaminants in the shuttle and the International Space Station is important to ensure the health and safety of astronauts, and equipment integrity. Three specific space applications have been identified that would benefit from a chemical monitor: (a) organic contaminants in space cabin air; (b) hypergolic propellant contaminants in the shuttle airlock; (c) pre-combustion signature vapors from electrical fires. NASA at Kennedy Space Center (KSC) is assessing several commercial and developing electronic noses (E-noses) for these applications. A short series of tests identified those E-noses that exhibited sufficient sensitivity to the vapors of interest. Only two E-noses exhibited sufficient sensitivity for hypergolic fuels at the required levels, while several commercial E-noses showed sufficient sensitivity of common organic vapors. These E-noses were subjected to further tests to assess their ability to identify vapors. Development and testing of E-nose models using vendor supplied software packages correctly identified vapors with an accuracy of 70-90%. In-house software improvements increased the identification rates between 90 and 100%. Further software enhancements are under development. Details on the experimental setup, test protocols, and results on E-nose performance are presented in this paper along with special emphasis on specific software enhancements.     

电子鼻及其在食品领域的应用

介绍了电子鼻的基本原理和组成,不同种类的电子鼻由不同的传感器阵列组成。并在应用方面可以对不同酒类的气味进行鉴别判断;对肉类进行微生物分析;对奶制品进行在线控制;还能够检测饮用水和饮料中不同微生物和重金属的含量;对不同品质的茶类能够迅速识别。     

基于集成气体传感器阵列的电子鼻系统

介绍一种基于集成气体传感器阵列的电子鼻系统硬件实现方法。描述了系统的一般组成,重点介绍了所采用的集成气体传感器及其信号拾取方法。该系统可实现对检测气体的自动数据采集、微机传送,具有高的灵敏性和可靠性。另外,对采用的集成气体传感器系列,该电子鼻系统具有一定的通用性。利用该系统对五种葡萄酒进行了检测,结果表明:该电子鼻系统可有效地用于葡萄酒的定性识别,识别准确率达到100%。     

基于PCA与BP混合神经网络算法的电子鼻系统

为了对食物品质进行非接触式评价,基于6种费加罗金属氧化物气体传感器阵列,通过由数据采集模块和微处理器模块组成的硬件设计方案,设计并研制了可对被测食物进行实时、无损检测的电子鼻系统。在软件设计方案上,该系统采用主成分分析(PCA)和反向传播(BP)混合神经网络模式,通过LabVIEW对气体"指纹信息"数据库进行分析。实验结果表明:该设计的电子鼻系统可以很好地区分不同种类的食醋,并提供了一种对食醋品质评价的便利方法。     

Electronic nose and sensorial analysis: comparison of performances in selected cases

Sensorial analysis based on the utilisation of human senses, is one of the most important and straightforward investigation methods in food analysis. It provides a unique information about the ‘food–man interaction’. Nevertheless, human senses, when considered as instruments, show several problems of reproducibility, stability and difficulties of expression, making it very hard to compare results between different panels. The electronic nose has been proven to be sufficiently accurate as an artificial approximation of the human olfaction apparatus when applied to well defined problems in food analysis. In this paper results obtained for tomato pastes and milk analysis, comparing a panel of tasters and an electronic nose will be presented and discussed.     

基于多BP子网络的电子鼻信息融合技术

针对电子鼻技术的应用中,利用常规BP(back-propagation)网络难以对复杂的混合气味进行识别这一问题,介绍了一种采用多BP网络联合进行电子鼻多传感器数据融合处理的新方法。利用这一方法并结合气体传感器阵列在不同温度条件下的响应信号,对不同品牌的葡萄酒样本进行定性识别,仿真验证结果表明该方法的识别准确率达到100%。     

基于Fe_2O_3系列气体传感器阵列的电子鼻系统

阐述了一种基于Fe2O3系列气体传感器阵列的电子鼻系统硬件实现方法及其系统的一般组成,介绍了Fe2O3系列气体传感器和传感器的加热电路。该系统以MSP430F149单片机为核心,实现对检测气体的自动数据采集、脱机和联机识别。利用该系统对甲烷、氢气和液化石油气进行检测,结果表明:该电子鼻系统能有效地对这3种气体进行定性识别,识别率接近100%。     

Improved digital photogrammetry technique for crack monitoring

Inspections to evaluate the safety, durability, and service life of aging infrastructure play an important role in determining the countermeasures that need to be taken, such as reinforcement, repair, and reconstruction. In infrastructure containing concrete, such as bridges and tunnels, crack widths and patterns on surfaces are two of the most important signs used to estimate durability. Current conventional techniques used for this purpose suffer from challenges such as tediousness, subjectivity, and high cost. Consequently, a new measurement technique that overcomes these challenges while measuring crack displacement with high accuracy and precision in aging civil engineering structures is needed. In this paper, we proposed a technique for measuring crack displacement using a digital camera image. In the proposed technique, reflective targets are established around both sides of a crack as gauges, and subsequent digital camera images of the targets are subjected to image processing to determine the displacements of the targets. These displacements can be measured using images captured from any arbitrary camera position. The results of experiments conducted to verify the efficacy of the proposed method show that crack displacements of less than 0.10 mm can be measured with high accuracy and precision using digital images captured at a distance of 10.0 m from the target, while less than 0.20 mm changes in the tensile displacement of the crack can be measured from an image captured at 25.0 m from the crack. Measurement results obtained from a tunnel are also presented to show that cracks in the walls of an actual tunnel can be identified through simple measurements. These measurements, taken over a period of one year, indicate that the tendency of crack displacement and slide movements are in close agreement.     

欧美电子监听技术标准研究

根据欧洲电信标准委员会（ETSI）及美国《通讯协助法》（CALEA）关于电子监听标准的研究和规定,本文分析了在电子监听中执法机构对电信服务提供者的要求、监听的相关数据类型以及交接接口标准等问题。对规范我国电子监听标准、开展电子监听工作有一定的借鉴和帮助。     

A new instrument with rainfall monitoring potential

Abstract

The new Special Sensor Microwave Imager (SSM/I) is introduced, and its global data acquisition pattern illustrated. Through an image for the morning of 29 July 1987 covering north-western Europe in general, and southern Britain in particular, its rainfall monitoring potential is illustrated and explained. An initial comparison with digital outputs from the FRONTIERS radar system of the U.K. Meteorological Office is presented, revealing very promising spatial correspondences between SSM/I and radar-derived rain areas.     

Electronic performance monitoring: A review of research issues

The research literature on electronic performance monitoring (EPM) has attributed different outcomes to monitoring, including improved worker performance, reduced job satisfaction and increased job stress. A variety of research methods (case study, cross-sectional and laboratory designs) has been utilized to study these effects of EPM. In this paper, these methods are reviewed, and the results of several studies are summarized. The existing literature often does not clearly specify what is meant by monitoring. Future research on outcomes associated with monitoring should describe carefully the type of monitoring technology and system used - who does the monitoring, when it is done, and what aspect of performance is monitored. It is further suggested that future EPM research should describe in greater detail the work environment, the job tasks, and the organizational climate of monitored and non-monitored workers to determine whether these groups are comparable with respect to these factors, and that observed outcomes are not misattributed to EPM.     

航空结构健康监测的压电夹层设计

根据智能夹层思想和真实航空飞行器结构特点,研究了面向航空结构健康监测的压电夹层技术,并将该技术应用到了某无人机机翼盒段结构健康监测验证实验中。实验结果表明:压电夹层工作性能稳定,寿命长,压电元件的一致性良好,抗干扰、串扰能力较好,该技术对于结构健康监测技术实用化具有推动作用。     

直接监测钢筋锈蚀的光纤传感技术

介绍了直接监测混凝土结构中钢筋锈蚀的光纤传感技术和各监测方法的原理、监测参数及优缺点,并提出改进这些监测方法的思路.鉴于土木工程中钢筋锈蚀环境的复杂性和监测的长期性,监测方法必须反映混凝土中钢筋锈蚀的实际环境,传感器设计必须保证监测精度和耐久性,并尽量扩大钢筋锈蚀率的测量范围,以使其在土木工程中具有可行性.     

无线技术在工业废气监测中的应用

<正>1概述随着工业化和城市化建设的发展,各种工厂及汽车等急速增长,工厂、汽车等排出的废气严重污染了大气,对人类的生活产生了极大的危害(图1)。世界各国对此表现出极大的重视,提出了各种保护环境的倡议并制定了各种环境保护的法律法规。     

无线技术在高速公路气象监测中的应用

<正>1概述高速公路是交通现代化的重要标志,也是国家现代化的重要标志。改革开放30年来,我国高速公路建设经历了从无到有、从起步建设到拥有5.39万公里网络的巨大变化,实现了跨越式的发展。高速公路的建设逐步向着高速、     

A video monitoring technique for investigating computer-based learning programs

Few studies of computer-based learning materials concentrate upon the learner-computer interaction. Fewer studies have focused on the way children learn science using computer-based learning programs. The studies that have been done employed observational methods. A video monitoring technique, which produces a synchronized record of the computer output and the children's use of the computer program is described. The technique affords a greater precision of data than observational techniques. A study which employed this technique is described.