声表面波辅助实现纸基微流分析

纸基微流器件往往难以实现样品前处理操作.提出了一种简单的纸基微通道制作方法及兼具有前处理操作功能的纸基微流分析方法.采用Protel设计微通道图案,采用印刷电路技术制作铜模板,并涂覆石蜡、覆盖滤纸,而后用电烙铁加热铜模板另一侧,熔融石蜡渗透入滤纸形成纸基微通道.制作的纸基器件放置于128°YX-LiNbO3压电基片上,当其上的叉指换能器在电信号作用下激发声表面波,输运待测微流体到达纸基微通道入口,并进而与其检测区中指示剂进行反应,实现微流分析.应用所提出的方法实现了葡萄糖和蛋白质的并行检测.该工作为纸基微流分析提供了一种新的纸基微通道的制作方法,同时,也为其解决了样品前处理操作难的问题,具有一     

Using multiple metrics for analysis of improvement

To make global decisions about a project or group of projects, it is necessary to analyse several metrics in concert, as well as changes in individual metrics. This paper discusses several approaches to collective metrics analysis. First, classification tree analysis is described as a technique for evaluating both process and metrics characteristics. Next, the notion of a multiple metrics graph is introduced. Developed initially as a way to evaluate software switch quality, a multiple metrics graph allows collections of metrics to be viewed in terms of overall product or process improvement.This work was done while the authors were affiliated with Contel Technology Center, Chantilly, Virginia, USA.     

基于声表面波技术探测微量气体的理论分析

声表面波延迟线振荡器的频率对沉积在延迟线表面上的薄膜很敏感,在延迟线路径上覆盖一层具有选择性的吸附薄膜,这层薄膜吸附对其敏感的气体物质后,其质量密度、弹性参数、介电常数、电导率都将发生变化。给出了传感器的理论分析,根据检测需要,设计最优化的气体传感器。     

Bayesian metrics for comparing response surface models of data with uncertainty

For many optimization applications a complicated computational simulation is replaced with a simpler response surface model. These models are built by fitting a limited number of evaluations of the full simulation with a simple function that captures the trends in the evaluated data. In many cases the values of the data at the evaluation points have some uncertainty. This paper uses Bayesian model selection to derive two objective metrics that can be used to determine which response surface model provides the most appropriate representation of the evaluated data given the associated uncertainty. These metrics are shown to be consistent with modelling intuition based on Occam’s principle. The uncertainty may be due to numerical error, approximations, uncertain input conditions, or to higher order effects in the simulation that do not need to be fit by the response surface. Two metrics, Q and G, are derived in this paper. The metric Q assumes that a good estimate of the simulation uncertainty is available. The metric G assumes the uncertainty, although present, is unknown. Application of these metrics in one and two dimensions are demonstrated. Received June 28, 2000     

Generalized metrics for the analysis of E-learning personalization strategies

For personalizing E-learning, several different strategies and characteristics can be used and considered by teachers and course authors/designers. In order to make appropriate decisions on how to best implement personalized E-learning, this paper focuses on the question: How to foresee personalization strategies that are appropriate for particular courses? To answer this question, we present an approach for recommending personalization strategies based on the learning objects included in the course as well as on how well they support particular combinations of learners’ characteristics. In particular, the paper presents generalized metrics which support teachers for analyzing and comparing personalization strategies, as well as deciding which one should be applied for personalizing each course. The approach was validated through experiments in order to test its feasibility and success when applied to a large number of learning objects and learners’ characteristics.     

Statistical methods for the analysis of software metrics data

The authors present case study applications of statistical methods for the analysis of software metrics data which recognize the discrete nature of such data. A procedure is also described which allows a component of complexity independent of size to be extracted from the usual Halstead's metrics and McCabe's cyclomatic number. The methods described are different from the usual regression and non-parametric methods previously applied to software metrics. With the software quality practitioner in mind, the paper explores how these new methods are helpful in understanding the relationships between software metrics.     

Materials choice criteria for surface acoustic wave sensors

The modern materials and types of the substrates used for the surface acoustic wave (SAW) devices are considered and their special requirements for the SAW sensors are discussed. A classification of the SAWsensors is given, and the factors of SAWsensors design and materials choice criteria are discussed.     

一种用于监控系统的监控指标趋势分析方法

提出一种用于监控系统的监控指标的趋势分析方法,包括两种趋势分析,分别为预测分析和周期性分析,前者通过线性回归算法和指数回归算法预测指标的未来值;后者通过三角函数回归算法计算指标的周期性参数。根据趋势分析结果和事先设定的报警阈值确定是否预先报警,绘制该指标变化的周期性曲线。该方法能够实现网络监控系统在监控指标发生违例前预先报警,自动生成指标变化周期性曲线,为监控系统增加了趋势分析功能。     

Managerial use of metrics for object-oriented software: anexploratory analysis

With the increasing use of object-oriented methods in new software development, there is a growing need to both document and improve current practice in object-oriented design and development. In response to this need, a number of researchers have developed various metrics for object-oriented systems as proposed aids to the management of these systems. In this research, an analysis of a set of metrics proposed by Chidamber and Kemerer (1994) is performed in order to assess their usefulness for practising managers. First, an informal introduction to the metrics is provided by way of an extended example of their managerial use. Second, exploratory analyses of empirical data relating the metrics to productivity, rework effort and design effort on three commercial object-oriented systems are provided. The empirical results suggest that the metrics provide significant explanatory power for variations in these economic variables, over and above that provided by traditional measures, such as size in lines of code, and after controlling for the effects of individual developers     

A review of metrics on permutations for search landscape analysis

Search landscape analysis has become a central tool for analysing the dependency of the performance of stochastic local search algorithms on structural aspects of the spaces being searched. Central to search landscape analysis is the notion of distance between candidate solutions. This distance depends on some underlying basic operator and it is defined as the minimum number of operations that need to be applied to one candidate solution for transforming it into another one. For operations on candidate solutions that are represented by permutations, in almost all researches on search landscape analysis surrogate distance measures are applied, although efficient algorithms exist in many cases for computing the exact distances. This discrepancy is probably due to the fact that these efficient algorithms are not very widely known. In this article, we review algorithms for computing distances on permutations for the most widely applied operators and present simulation results that compare the exact distances to commonly used approximations.     

Power consumption analysis of surface acoustic wave sensor systems using ANSYS and PSPICE

The power consumption of a surface acoustic wave (SAW) sensor system was investigated using ANSYS and PSPICE. Simulation results show that several design parameters of the surface acoustic wave sensor, such as the center distance between two interdigital transducers (IDT), the thickness of the piezoelectric substrate, the finger space of the IDT, etc., can greatly affect the power consumption of the whole system. The results of this study will be helpful to optimum design and fabricate the SAW sensor systems with very low-power consumption.     

Optimal pressure-sensitive cuts for surface acoustic waves on langasite

The crystal langasite (La3Ga5SiO14; abbreviated as LGS), not only has temperature compensated orientations for SAW, but also has a stronger electromechanical coupling coefficient k2 of 0.5%, which is about 2―3 times greater than that of quartz. Another a…     

Semantic metrics through error flow analysis

Error flow analysis of a computer program derives information about how potential data state errors may arise and propagate as the program executes. This information can be used to measure the semantic effects on an execution path caused by changing statements along the path. A dynamic style of error flow analysis is defined and a system for performing this analysis called Dynamic Error Flow Analysis (DEFA) is described. Examples of several semantic metrics produced by running DEFA are given.     

An empirical analysis of package-modularization metrics: Implications for software fault-proneness

ContextIn a large object-oriented software system, packages play the role of modules which group related classes together to provide well-identified services to the rest of the system. In this context, it is widely believed that modularization has a large influence on the quality of packages. Recently, Sarkar, Kak, and Rama proposed a set of new metrics to characterize the modularization quality of packages from important perspectives such as inter-module call traffic, state access violations, fragile base-class design, programming to interface, and plugin pollution. These package-modularization metrics are quite different from traditional package-level metrics, which measure software quality mainly from size, extensibility, responsibility, independence, abstractness, and instability perspectives. As such, it is expected that these package-modularization metrics should be useful predictors for fault-proneness. However, little is currently known on their actual usefulness for fault-proneness prediction, especially compared with traditional package-level metrics.ObjectiveIn this paper, we examine the role of these new package-modularization metrics for determining software fault-proneness in object-oriented systems.MethodWe first use principal component analysis to analyze whether these new package-modularization metrics capture additional information compared with traditional package-level metrics. Second, we employ univariate prediction models to investigate how these new package-modularization metrics are related to fault-proneness. Finally, we build multivariate prediction models to examine the ability of these new package-modularization metrics for predicting fault-prone packages.ResultsOur results, based on six open-source object-oriented software systems, show that: (1) these new package-modularization metrics provide new and complementary views of software complexity compared with traditional package-level metrics; (2) most of these new package-modularization metrics have a significant association with fault-proneness in an expected direction; and (3) these new package-modularization metrics can substantially improve the effectiveness of fault-proneness prediction when used with traditional package-level metrics together.ConclusionsThe package-modularization metrics proposed by Sarkar, Kak, and Rama are useful for practitioners to develop quality software systems.     

覆盖聚合物敏感膜的水平剪切型声表面波气体传感器机理分析

采用微扰理论分析了覆盖聚合物敏感膜的水平剪切型声表面波气体传感器(SH-SAW)的响应机理.以针对有机磷毒剂具有良好选择性的含氟多羟基聚硅氧烷(FPOL)膜材料为例,分析了聚合物膜厚以及传感器工作频率在敏感膜吸附气体时对传感器响应的影响.计算结果表明,SH-SAW气体传感器对于不同浓度的甲基磷酸二甲酯(DMMP)气体响应随FPOL膜厚和传感器工作频率的改变呈现非线性变化.为了获得线性特性的传感器响应及较小的声波衰减,在一定的DMMP气体浓度检测范围内,通过理论计算提取出了优化的FPOL敏感膜膜厚和传感器工作频率等参数.     

High-throughput micromixers based on acoustic streaming induced by surface acoustic wave

Flow characteristics in microfluidic devices is naturally laminar due to the small channel dimensions. Mixing based on molecular diffusion is generally poor. In this article, we report the fabrication and characterization of active surface-acousticwave-driven micromixers which exploit the acoustic streaming effect to significantly improve the mixing efficiency. A side-by-side flow of water and fluorescent dye solution was driven by a syringe pump. Surface wave with a frequency of 13 MHz was launched perpendicular to the flow. The wave was generated by two designs of interdigitated electrodes on LiNbO₃ substrate: parallel electrodes and focusing electrodes. The mixing efficiency was observed to be proportional to the square of the applied voltage. Under the same applied voltage, the focusing type offers a better mixing efficiency. The fabrication of the micromixer is compatible to current technology such as soft lithography and deep reactive ion etching. Despite the high throughput and fast mixing time, the mixer design is simple and could be integrated into any microfluidic platform.     

声表面波RFID接收机的设计

设计了一款基于超外差技术的声表面波SAW RFID读卡器,其工作频率在915 MHz。该读卡器不仅可以在金属物体、高温、强磁场干扰等恶劣环境中正常工作,而且在不增加任何传感器的情况下可以反映出物体的温度值。详细阐述了整个接收机的设计方案,给出了硬件模块的电路设计,并对镜像干扰及其抑制方法进行了研究。     

声表面波阵列传感器研究进展

声表面波(SAW)阵列传感器具有许多独特的优点,目前已成为检测化学毒剂的重要手段之一:近年来,随着以SAW阵列传感器为主要技术的电子鼻的发展,使得SAW阵列传感器在食品检测、环境治理等领域得到了广泛应用.对SAW阵列传感器的发展及其应用进行了综述.     

常见气体声表面波传感器研究进展

声表面波(SAW)气体传感器由于具有响应时间快、灵敏度高、体积小、成本低、稳定性好等特点受到广泛关注.本文侧重从敏感材料方面介绍了用于检测几种常见的有毒气体的声波面波传感器的研究进展.     

面向对象设计复杂性度量计算与分析

软件维护在软件开发过程中占有相当重要的位置,但是其成本往往是很难控制的.在对一种能够对软件维护性能进行预测的面向对象复杂性度量进行分析的基础上,结合实际情况分析了该算法集3个度量的缺点及联系.对于3个度量不够深入的地方补充了一些新观点.