Design and Construction of Electronic Nose for Multi-purpose Applications by Sensor Array Arrangement Using IBGSA

Technological progresses in the gas sensor fields provide the possibility of designing and construction of Electronic nose (E-nose) based on the Biological nose. E-nose uses specific hardware and software units; Sensor array is one of the critical units in the E-nose and its types of sensors are determined based on the application. So far, many achievements have been reported for using the E-nose in different fields of application. In this work, an E-nose for handling multi-purpose applications is proposed, and the employed hardware and pattern recognition techniques are depicted. To achieve higher recognition rate and lower power consumption, the improved binary gravitational search algorithm (IBGSA) and the K-nearest neighbor (KNN) classifier are used for automatic selecting the best combination of the sensors. The designed E-nose is tested by classifying the odors in different case studies, including moldy bread recognition in food and beverage field, herbs recognition in the medical field, and petroleum products recognition in the industrial field. Experimental results confirm the efficiency of the proposed method for E-nose realization.     

炭黑填充聚乙烯导电复合材料气敏性能研究

采用溶液共混法成功制备出炭黑/聚乙烯导电气敏复合材料,研究了在苯、甲苯、二甲苯三种有机溶剂蒸汽中的电阻变化.实验结果表明,该复合材料在二甲苯蒸汽中电阻变化最大,在苯蒸汽中电阻变化最小.进一步研究了其在100 ppm至800 ppm(ppm=10-6)二甲苯蒸汽中的气敏响应性,实验结果表明:复合材料的灵敏度从0.04增大至0.11.     

Poly(3-hexylthiophene) and hexafluoro-2-propanol-substituted polysiloxane based OFETs as a sensor for explosive vapor detection

The organic field effect transistors (OFETs) with regioregular poly 3-hexylthiophene (rr-P3HT) and hexafluoro-2-propanol-substituted polysiloxane (SXFA) as an organic layer, have been used for detection of explosive vapors with excellent sensitivity of less than 70 ppt for 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and less than 100 ppt for 2,4,6-trinitrotoluene (TNT). The sensor response (% change in saturation current) was found to be 125 ± 10% for TNT and 90 ± 10% for RDX. It was also observed that the incorporation of Cu^II tetraphenylporphyrin (CuTPP) into rr-P3HT/SXFA matrix resulted in an improved selectivity for the vapors of nitro based analytes (TNT, RDX and DNB) as compared to the vapors of non explosive oxidizing agents such as nitrobenzene (NB), benzoquinone (BQ) and benzophenone (BP). This is attributed to the increased binding of the vapors containing nitro compound to the thin films due to the presence of CuTTP. Spin coated thin films were further characterized by Atomic Force Microscopy (AFM) and Electrostatic Force Microscopy (EFM).     

监测挥发性有机物的SAW传感器的研究进展

综述了可以连续操作和用于原位监测有机挥发性化合物的声表面波(SAW)化学传感器的研究进展。不锈钢包装和集成电路板的应用,使SAW传感器可以用于空气、土壤和水等在内的多种环境中监测有机挥发性化合物(VOCs)。介绍了根据常见地下水污染物氯代脂肪烃(如三氯乙烯)选择的高分子膜以及对传感器进行的优化。     

Optical parameters of calix[4]arene films and their response to volatile organic vapors

The Langmuir-Blodgett (LB) technique was employed to produce thin LB films using an amphiphilic calix-4-resorcinarene onto different substrates such as quartz, gold coated glass and quartz crystals. The characteristics of the calix LB films are assessed by UV-visible, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR) measurements. UV-vis and QCM measurements indicated that this material deposited very well onto the solid substrates with a transfer ratio of >0.95. Using SPR data, the thickness and refractive index of this LB film are determined to be 1.14 nm/deposited layer and 1.6 respectively. The sensing application of calixarene LB films towards volatile organic vapors such as chloroform, benzene, toluene and ethanol vapors is studied by the SPR technique. The response of this LB film to saturated chloroform vapor is much larger than for the other vapors. The response is fast and fully recoverable. It can be proposed that this sensing material deposited onto gold coated glass substrates has a good sensitivity and selectivity for chloroform vapor. This material may also find potential applications in the development of room temperature organic vapor sensing devices.     

Improvement of gas sensing performance of carbon black/waterborne polyurethane composites: Effect of crosslinking treatment

When carbon black (CB) filled waterborne polyurethane (WPU) composites are exposed to organic solvent vapors, electrical resistance of the materials increases rapidly. They can thus serve as gas sensors. To improve the composites’ performance for practical applications, crosslinking agent was added to the composite latexes, forming intra-molecular crosslinked networks among the matrix polymer of the composites. The method greatly increased the filler/matrix interfacial interaction and reduced the mobility of CB particles. In the composites that had absorbed solvent vapors, reconstruction of conduction paths through re-aggregation of the disconnected filler particulates became difficult. As a result, the unwanted negative vapor coefficient (NVC) effect was significantly weakened, while the gas sensitivity and the performance reproducibility were enhanced as well.     

基于电子鼻系统的番茄苗不同种类损伤的区分效果研究

通过对早疫病病害番茄苗、灰霉病病害番茄苗、机械损伤番茄苗和对照番茄苗的电子鼻响应信号的对比,可以看出不同处理的番茄苗样本电子鼻的响应信号是不同的,表明用电子鼻响应信号对番茄苗不同种类损伤进行预测是可行的.从PCA结果来看,早疫病病害的番茄苗和灰霉病病害的番茄苗能很好区分开,机械损伤的番茄苗和正常处理的番茄苗产生了重叠现...     

Applying reliability models to the space shuttle

The experience of a team that evaluated many reliability models and tried to validate them for the on-board system software of the National Aeronautics and Space Administration's (NASA's) space shuttle is presented. It is shown that three separate but related functions comprise an integrated reliability program: prediction, control, and assessment. The application of the reliability model and the allocation of test resources as part of a testing strategy are discussed     

A Software-Reuse Approach to Build Monitor Programs for Soft Real-Time Applications

Thispaper describes the implementation of an integration frameworkto build real-time monitor programs based on software reuse.A custom-made real-time monitor program can be built very quicklyby integrating existing monitor programs on commercial operatingsystems, where limited real-time system support is provided.We address issues related to software control, output re-processing,data age, and interactivities of program executions. The feasibilityof this framework is demonstrated by the construction of an integrationenvironment and a monitor program built by the environment forsoft real-time applications in the Microsoft Windows operatingsystems. We also measure the incurred system overheads of thisapproach.     

Orthogonal gas sensor arrays with intelligent algorithms for early warning of electrical fires

The feasibility of utilizing chemical sensor arrays and multivariable analyses as the basis for an early-warning combustion alarm for electrical fires was evaluated. During the pre-combustion phase of electrical fires, electronic components will heat up, resulting in an out-gassing of chemical vapors, which generally will precede the formation of smoke, scorching and fire. A variety of materials (PVC, Teflon^®, Kapton^®, and silicone rubber) that are frequently used as wire insulation were subjected to electrically induced thermal excursions, thereby simulating an electrical failure and possible pre-combustion condition. The off-gassing vapors from the various coatings can serve as chemical signatures for a pending fire and were detected by an array of chemical sensors (e.g., an electronic nose). Principal component analyses and KNN identification algorithms applied to the sensor response patterns successfully identified the various vapor sources. A 20-sensor array including electrochemical sensors, quartz microbalance (QMB) sensors with different polymer coatings, and heated metal oxide sensors (MOXs) was evaluated and the optimal performance was obtained using the electrochemical and MOXs. The use of heterogeneous orthogonal sensors increased the information content of sensor array signals and a diminutive array can still identify fire materials and extent of damage. The small, lightweight, inexpensive and low power sensors used to detect vapors during pre-fire conditions were ideal for space or commercial aircraft applications.     

基于AOP技术的通用线程监控平台的研究与实现

在传统的OOP编程中,由于需求空间是N维而实现空间是一维的,导致了软件开发中横切关注点的代码纠缠问题,严重影响了软件的质量.作为OOP的补充,AOP很好地解决了横切关注点带来的问题,提供了核心关注点和横切关注点互相分离的解决方案.本文从具体工程中开发线程监控这一需求所暴露的问题出发,提出了为什么需要AOP编程;然后着重讨论如何通过AOP技术解决这一问题,提出并实现了基于AOP技术的通用线程监控平台.该平台可以在不手工改变系统源代码的情况下通过工具植入系统内部,实现对运行线程信息的监视、对指定线程运行速度的变换和对整个系统运行行为的控制.     

A style for integrating MS‐Windows software applications to client–server systems using Java technology

Developing software systems by integrating the existing applications/systems over the network has become an established and practical technique. The Microsoft (MS) Windows operating systems today support a huge number of software applications. If these commercial applications could be transformed to software components, this may accelerate the construction of new components. This paper proposes an architectural style to support a three‐phase process for integrating MS‐Windows applications in a distributed system using Java technologies. This style provides a solution with clear documentation and sufficient information that is helpful for the rapid integration of MS‐Windows applications. Finally, an exemplary graphical construction part management system that assembles two MS‐Windows applications was developed in this study to demonstrate the feasibility of this style. Copyright © 2006 John Wiley & Sons, Ltd.     

Detection and discrimination of coliform bacteria with gas sensor arrays

Electronic noses, which are used for characterizing complex vapors and aromas, may be useful for detection of bacterial contamination or diagnosis of infections, if minimal standards of selectivity and sensitivity can be met. A culture of Enterobacter aerogenes is readily discriminated from an Escherichia coli strain using principal components analysis (PCA) of data generated by an array of eight quartz microbalance (QMB), eight metal oxide semiconductor (MOX), and four electrochemical gas sensors. Two strains of E. coli were not discriminated under identical conditions. Retaining headspace air in a sealed vial containing growing bacteria results in an enhancement of sensitivity, so that a concentration of bacteria of about 5×10⁸/ml may be both detected and distinguished from other species. Improvements in sensitivity to levels useful for practical applications will require enhancement of sensors, sampling system, and pattern classification.     

基于HACMP V5的信息系统高可用性应用研究和管理

HACMP是IBM公司在P系列AIX操作系统上的高可用集群软件,目的是配置冗余,消除单点故障,保证整个系统连续可用性和安全可靠性。对如何应用HACMP V5实现主机和信息系统高可用性进行了技术研究,介绍了无锡供电公司应用HACMP V5保障主机和管理信息系统高可用性的实现过程,并结合实际经验对日常的运行维护管理要点进行整理,为企业实施信息系统高可用性提供了参考。     

Vapor recognition with an integrated array of polymer-coated flexural plate wave sensors

Preliminary testing of a prototype instrument employing an integrated array of six polymer-coated flexural plate wave (FPW) sensors and an adsorbent preconcentrator is described. Responses to thermally desorbed samples of individual organic solvent vapors and binary and ternary vapor mixtures are linear with concentration, and mixture responses are equivalent to the sums of the responses of the component vapors, which co-elute from the preconcentrator in most cases. Limits of detection as low as 0.3 ppm are achieved from a 60-s (34 cm³) air sample and peak widths at half-maximum range from 1 to 4 s. Tests at different flow rates suggest that the kinetics of vapor sorption in the sensor coating films may limit responses at higher flow rates, however, low data acquisition rates may also be contributory. Assessments of array performance using independent test data and Monte Carlo simulations with pattern recognition indicate that individual vapors and certain binary and ternary mixtures can be recognized/discriminated with very low error. More complex mixtures, and those containing homologous vapors, are problematic. This is the first report demonstrating multi-vapor analysis with an integrated FPW sensor array.     

Monitoring of deforestation and land use in Indonesia with multitemporal ERS data

The ESA ERS1-pilot project PP2-D11 was aimed at investigating the capabilities of the ERS-1/2 satellites for continuous land use and deforestation monitoring over a period of 5 years (1993-1997) in a tropical rain forest environment. Deploying texture analysis techniques, several land use classes and different forest types could be identified in single ERS-1/2 Synthetic Aperture Radar (SAR) images. The texture features created allowed the discrimination of (1) undisturbed forest of at least two different types, (2) shifting cultivation and agriculture, (3) secondary forest, (4) selectively logged forest, (5) clearings by fire and clearcutting, and (6) settlements and major roads. The results of multitemporal data analysis showed that changes in area of classes (2), (4) and (5) can be readily detected in a multitemporal sequence of ERS SAR images. KFA1000 photographs from the Russian MIR Space Station, Landsat Thematic Mapper (TM) images and ground data acquired during two extensive field excursions served as a reference for the interpretation of the ERS images. All evaluation procedures were performed with standard computer equipment and commercial software packages to ensure operationality and technology transfer towards Indonesia. The results suggest that the European radar satellites ERS-1/2 can be used to monitor and analyse forest conversion and land use patterns in tropical rain forests at scales 1:100000.     

A distributed Bragg reflector porous silicon layer for optical interferometric sensing of organic vapor

In this study, we successfully demonstrated the rapid, sensitive, and reversible sensing of organic vapor using a distributed Bragg reflector (DBR) porous silicon (PS) layer. We fabricated the DBR PS layer on a p⁺-type silicon substrate and investigated its reflectance spectra before, during, and after exposure to the different concentrations of various organic vapors. When the DBR PS layer sample was exposed to methanol, acetone, ethanol, and isopropanol vapors, the maximum reflectance peak promptly shifted toward longer wavelengths by about 4.5, 23.2, 26.0, and 38.2 nm, respectively. We determined that the red-shift in the reflectance spectrum could be attributed to the changes in the refractive index induced by the capillary condensation of the organic vapor within the pores of the DBR PS layer. The DBR PS layer showed excellent sensing ability under the different concentrations and types of organic vapors. In addition, a slight hysteresis of the red-shift was observed during repeated exposure to organic vapors at different concentrations. After removing the organic vapors, the reflectance spectrum promptly returned to its original state.     

Kinco CD伺服成功应用于喷气织机

喷气织机是采用喷射气流牵引纬纱穿越梭口的无梭织机。Kinco伺服系统在喷气织机送机,卷取机构上优异的表现得到了客户的高度认可和肯定。     

NASA's Manned Spacecraft Computers

Many people believe that NASA's extensive use of computers has kept the agency at the forefront of computer development. This study evaluates the hypothesis in regard to computers used on board manned spacecraft. The results show that NASA's contributions to computer science were made primarily in the areas of software verification and fault tolerance, and that overall, NASA has adopted proved technology for manned space flight operations. This technology is consistently behind the state of the art in terms of hardware, but the continued use of older technology in manned spacecraft is not necessarily a negative development. The computer power used in the Apollo, Gemini, and shuttle programs has been sufficient for the requirements of the missions. Most important, reliability has been ensured.     

轮胎压力监测及控制系统

轮胎内的气压实时状况对于汽车的行驶安全以及性能来说都是非常重要的,如何对轮胎内的气压进行监测、控制、以及保持汽车所有轮胎内的气压相对平衡,一直以来就是一项十分重要的研究课题。然而目前市场上应用的轮胎压力监测系统TPMS（Tire Pressure Monitoring System）,仅仅能对轮胎的气压进行监测,而不能自动的对轮胎内的气压做出反馈,来及时控制轮胎内的气压并保持所有轮胎内的气压平衡。为了解决这个问题,介绍设计的一种闭环汽车轮胎压力监测及控制系统,主要包括总体方案、硬件设计、软件设计、加密算法、性能分析。经试验和实际测试表明：该系统监测的数据可靠,更新及时,系统能有效的保持汽车所有轮胎内的气压相对平衡来增加了汽车的燃油效率,有很强的实用性。