网络化智能传感器中以太网接口设计

当前传感器向着微型化、数字化、智能化、网络化的方向发展,论文从网络化智能传感器的结构和特点入手,结合以太网和TCP/IP协议的功能特点,以W78E58单片机为核心控制器,以8029芯片为网络接入模块,提出了一种基于以太网的智能传感器设计思想,重点论述了该网络传感器的网络接口的软硬件设计方法.实验表明,采用该方法设计的以网络传感器具有良好的检测性能和网络通信性能,并且具有成本低廉、结构简单、组网灵活等优点.该网络传感器已经成功应用在广东省农业现代化的环境因子网络测控平台上.     

一种新的基于漫游代理的定向路由树算法

分析了以数据为中心的无线传感器网络中的定向扩散路由算法,提出了一种基于随机漫游的具有路由修复agent的定向路由树算法.该算法用泛洪策略构造一棵以汇聚节点为根的定向汇聚树,随后agent以等概率的方式在各个相邻传感器节点之间移动,当agent发现某两节点之间不再相邻时,即采取以该节点为中心的、逐步增加搜索范围的定向汇聚树的层次修复工作.研究表明,该算法具有良好的路由修复功能,同时也能节省能量并延长无线传感器网络的寿命.     

一种基片式光纤光栅应变增敏传感器

针对传统裸光栅直接粘贴式应变传感器应变灵敏度小的缺陷,提出了一种基片式光纤光栅应变增敏传感器,通过设计杠杆增敏结构的封装基片实现对光纤光栅的应变增敏.该传感器具有较大的应变放大机制,其测量精度与稳定性超过了裸光纤光栅.建立了该传感器的理论感知模型,并进行了与有限元仿真分析.由等强度悬臂梁标定实验可得该传感器实际应变灵敏度为6.122 pm/με,与理论结果和仿真结果一致,且线性度达到0.99998.通过动态激振实验对该应变增敏传感器的动态响应进行研究,实验结果表明该传感器能够在0～100 Hz范围内保持一致的增敏效果,能够良好的跟踪动态应变.该传感器在大型机械装备的健康监测与故障诊断方面具有良好的应用前景.     

静电自组装技术制备多巴胺传感器的研究

利用静电自组装技术研制一种多巴胺传感器.以高纯度Pt丝为基体,利用壳聚糖(chitosan)结合静电自组装方法固定酪氨酸酶(tyrosinase),再修饰Nafion膜,制备复合膜修饰的新型多巴胺传感器,并用该传感器监测给药后大鼠尾核中多巴胺浓度.测试结果显示:传感器线性范围为5×10-7～5×10-4 mol/L,R2=0.9961;重复性误差为3.43%;给药后,该传感器检测结果显示多巴胺浓度与药物剂量间存在相关性,达峰时间为40～45 min.该传感器具有良好的选择性、稳定性和重现性;在体测定结果表明:该传感器可用于在体监测多巴胺的实验研究.     

基于LCP衬底的柔性湿度传感器研究

介绍了一种新型柔性电容式湿度传感器.该柔性电容式湿度传感器采用液晶高分子聚合物(LCP)作为衬底,金属铜(Cu)作为叉指电极,聚酰亚胺(PI)作为湿度传感器的湿敏介质.LCP衬底的应用使得该传感器具有良好的柔性和可弯曲性.该柔性湿度传感器与传统硅基湿度传感器相比较具有成本低廉、结构简单、制作方便等优点.该柔性湿度传感器在25℃下的平均灵敏度为0.04%pF/%RH,最大回滞为±4.16%RH,其平均灵敏度在25℃~70℃范围内受温度影响较小.在25℃下其响应时间和恢复时间分别为36 s和39 s.该柔性湿度传感器可以应用于环境湿度检测、人工电子皮肤系统和可穿戴设备等领域.     

基于硼掺杂金刚石电极的酚生物传感器的研究

该文研究了以硼掺杂金刚石为基底电极的酪氨酸酶传感器.该酶传感器对酚的催化作用强于以玻碳为基底电极的酪氨酸酶传感器.在浓度为1.0×10-8～1.0×10-5mol/L的范围内传感器对邻苯二酚的响应具有良好的线性关系,检测下限为5.2×10-9mol/L.酶电极的Michaelis-Metent常数(Kapp m)为33.65μmol/L.酶电极对苯酚和对甲苯酚也有良好的响应,线性范围分别为:5.0×10-8～2.0×10-5mol/L、5.0×10-8～5.0×10-6 mol/L.酶传感器有较好的稳定性和重现性.     

固体电解质电位型甲烷传感器的气敏性能研究

研究了甲烷浓度和工作温度对氧化锆基混合电位型传感器响应值的影响.以氧化钇稳定的氧化锆(YSZ)为固体电解质,氧化锡(SnO2)为工作电极的传感器对(200~1000)×10 -6浓度的甲烷具有良好的传感性能,传感器响应值与甲烷浓度的对数值呈良好的线性关系,传感器在650℃时具有良好的传感性能,其中响应时间和恢复时间均低至5 s.     

基于纳米金探针的HCG快速定量生物传感器研究

一种基于免疫胶体金技术的快速定量生物传感器研究是以人绒毛膜促性腺激素(HCG)为切入点,成功制备出HCG快速定量生物传感器试条,进行免疫胶体金特征波长选取及最适抗体包被用量研究.使用该生物传感器配合自制光学定量检测系统进行HCG抗原初步实验,在10～50μg/mL浓度范围内获得检测结果.该定量该系统具有快速响应(15 min)、需样量小(20μL)、自动量化判读等特点,在临床急诊、社区农村卫生筛查等领域具有良好的应用前景.     

现场总线温湿度传感器节点的设计及应用

针对提高温湿度程序控制系统性能的需要,给出了以AT89C51CC01微控制器和数字温湿度传感器SHT71为核心组成CAN现场总线温湿度传感器节点的设计方法及其硬件构成,探讨了由温湿度传感器节点组成的多传感器信息融合技术及其在温室环境温湿度程序控制系统中的应用.文章认为该温湿度传感器节点性能先进、适用性强、成本低、可靠性高、使用方便,在温湿度控制系统和现场总线测控系统中具有良好的应用前景.     

传感器输出信号通用线性处理电路的研究

根据电量输出传感器测量物理量的范围,平分二段,分别建立拟合回归方程,并用电路实现之.这种线性处理方法具有通用性.以K型热电偶传感器为实验例子,未经线性处理前,理论线性度为3.2%,线性处理后,理论线性度为0.015%.测量数据标准差为0.00138.结果表明,该方法测量效果良好.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).