基于WSN的温室温度分布式事件触发控制系统研究

在温室温度控制系统中,针对无线传感器网络的通信带宽及节点资源受限问题,提出分布式事件触发控制方案。在分布式事件触发机制下,各传感器节点基于自身信息,仅在系统有控制需求时发送状态采样值,有效地节约了系统资源。因为算法简单且能改善早熟收敛问题,采用基于混沌变异的粒子群算法计算最优控制量,仿真表明,分布式事件触发机制下节点数据发送率大大降低,系统仍能达到满意的控制效果。     

基于ZigBee和WLAN的智能家居监控系统的设计

综合zigBee无线传感器网络和无线局域网(WLAN),设计了集多传感、分布式处理和事件触发监视于一体的具有双层网络结构的智能家居多媒体监控系统.ZigBee网络由标量传感节点和多媒体传感节点(网关)基于IEEE 802.15.4/ZigBee协议构建.负责采集标量数据上传到WLAN或执行来自上层的指令.多媒体传感节点基于WLAN连接到远程监控中心形成远程视频监控网络,将ZigBee网络上汇聚来的传感数据、报警信号和压缩视音频流等多媒体数据发送到监控中心及用户.利用此系统,为用户提供家居环境参数监测、报警、事件触发或持续的远程家居监控功能.     

ZigBee技术在智能家居系统中的应用

基于ZigBee协议栈构建了组网配置灵活且稳定的无线自组织网络系统,并在此基础上通过利用各种传感器和光耦合嚣等将其应用于智能家居系统.采用温度传感器和光照度传感嚣采集信息监测环境,根据环境温度和光照强度信息,使用光耦合嚣智能控制空调电源和电灯开关,同时设计遥控节点和上位机可以随时控制开关.     

基于压电振动能量采集器的无线监测传感节点

环境振动状况监测对设备的安全运营至关重要。通过压电振动能量采集器可实现对环境振动信息的感知,再经过智能信息处理方法无线监测设施的安全运营状态。将无线传感与深度学习相结合,在充分研究压电振动能量采集器输出信号特征的基础上,提出了优化的卷积神经网络模型,用于识别环境异常振动模式,并设计实现了智能感知无线监测传感节点。系统工作时,节点可监测环境振动、温度信息并报警异常事件。测试结果表明, 该传感节点在无线传输距离超过100 m 的情况下,实现了环境振动事件的实时监测,报警时间小于5 s,环境振动模式识别准确率可达95．7%,监测环境温度状况并准确报警异常燃烧事件的时间小于3．7 s。该节点在野外目标监测等场合有广泛的应用前景。     

基于ZigBee的低功耗无线传感节点设计与实现

以CC2430芯片为核心设计一种用于温湿度测量的无线传感节点,为了降低节点功耗,在ZigBee协议栈的基础上进行改进,为传感节点设计了空闲、触发和主动等3种工作模式,使节点能够按照实际需求控制采样的时机和速率,以减少传感节点用于无线通信的能量开销,从而满足无线传感器网络对节点低功耗的设计要求,同时根据已知参数预测传感节...     

Zigbee睡眠模式与路由算法在智能家居中的性能研究

针对Zigbee工作模式在智能家居系统中的能耗分析,从无线节点睡眠模式入手,研究分析改进树型路由算法(Cluster-tree)配合睡眠机制在智能家居系统中的应用。重点考虑了Zigbee无线模块的两种工作模式在智能家居系统中的能量消耗,以此为平台改进路由算法并结合无线节点睡眠机制。仿真结果表明,改进路由算法并合理设定无线节点睡眠时间,既能保证无线网络通信质量,又能更进一步降低系统无线节点能耗,并降低无线节点的路由开销。     

事件触发下非线性网络控制系统的H∞ 故障检测

研究了非线性网络控制系统存在时变时滞、丢包、传感器扇区非线性时的故障检测问题.针对时间触发周期采样带来的网络资源浪费问题,提出了一种满足给定触发条件来判断采样数据是否需要传输的事件触发机制.根据Lyapunov稳定性理论和线性矩阵不等式将故障检测问题转换成求解H∞凸优化问题.最后,以电机伺服控制系统为例,通过Matla...     

基于聚类模型预测的无线传感网自适应采样技术研究

该文利用无线传感网(WSNs)的数据空间相关性,提出一种基于数据梯度的聚类机制,聚类内簇头节点维护簇成员节点的数据时间域自回归(AR)预测模型,在聚类内范围实施基于预测模型的采样频率自适应算法。通过自适应优化调整采样频率,在保证数据采样精度的前提下减少了冗余数据传输,提高无线传感网的能效水平。该文提出的时间域采样频率调整算法综合考虑了感知数据的时空联合相关性特点,仿真结果验证了该文算法的性能优势。     

时间触发总线技术研究与实现

传统的机载总线采用事件触发的机制,时间传输具有不确定和不可预知性的特点。随着飞机系统对总线的确定性、安全性和可靠性的指标要求越来越高,基于时间触发机制的TTP总线技术获得了越来越广泛的应用。在分布式实时控制系统中,采用时间触发模式能够将可用的通信资源合理地静态分配给系统内每个节点,通过时间触发的协议排除了事件触发通信协议要考虑的资源共享冲突和恢复操作等问题,提高系统的确定性和安全性。文章对TTP总线技术做出分析,并提出一种TTP节点的设计与测试方法。     

基于ZigBee的智能家居设备设计

针对传统智能家居存在布线困难、移动性差、维护成本高等缺点,提出了一种基于Zig Bee无线传感网技术的智能家居方案。整个系统以S3C2440作为服务器,结合Zig Bee组网技术,实现了通过协调器控制子节点终端。具体的子节点终端设备由STM32单片机控制,设备包括家居环境信息实时显示、十级调光和模拟窗帘。经测试验证,系统在液晶屏上实时显示当前日期(包括阴历和星期)、时间以及室内温度;通过在智能手机终端界面发送指令,灯光亮度和窗帘闭合度实现0~100%可调。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.