融合反距离加权和矩阵填充的位置指纹库构建

为解决位置指纹定位在离线阶段构建位置指纹库时耗费的人力和时间成本较大,构建指纹库效率低和利用空间插值法构建的指纹库精度不高的问题,提出了一种融合反距离加权和矩阵填充的位置指纹库构建算法。该算法仅需人工采集定位区域内少量参考点的接收信号强度值用作信标点指纹信息,结合反距离加权算法特性计算出次信标点指纹信息,根据位置指纹库数据矩阵的低秩性,应用奇异值阈值矩阵填充算法构建出位置指纹数据库。仿真实验结果表明,所提算法有效降低了矩阵填充算法构建位置指纹库所需的人工和时间成本,构建出的位置指纹库定位性能优于反距离加权和克里金空间插值法,接近传统人工采集法,显著地提高了位置指纹库的构建效率。     

基于RSS空间线性相关的WLAN位置指纹定位算法

针对RSS(接收信号强度)时变性以及不同终端信号接收能力的差异性,导致WLAN位置指纹定位不稳定的问题,基于RSS空间线性相关性提出一种新颖的位置指纹定位算法.在每个参考点分别采集多组RSS样本形成特征矩阵,并构建离线位置指纹数据库.定位时,通过计算实时RSS矩阵与指纹库参考点相关性,得到最相关的k个参考点,利用二次加权质心算法计算用户的最终位置.为了有效降低信号时变性的影响,采样时进行了滤波、排序等处理,构建离线指纹数据库时尽量增加采样次数,但需要对样本进行聚合处理以适应定位相关性计算.实验结果表明,该算法在保证较高定位准确度的同时,针对不同终端有更好的定位稳定性.     

基于线性化数据处理的位置指纹算法

为了进一步提高室内定位精度,提出了一种改进的位置指纹定位算法。该算法离线阶段采集采样点信号强度构建数据库,在线阶段采用线性拟合和最小二乘法相结合求出待测点的估计位置。仿真结果表明,改进的算法尤其适用于不大于10 m~*10 m的小区域网络的高精度定位,与传统的位置指纹算法相比较,改进的位置指纹定位算法使得平均定位误差降低了22.2%,提高了定位精度。     

基于RSS相关性的位置指纹室内定位方法

解决设备差异性造成的Wi-Fi信号强度不确定问题是位置指纹室内定位应用与推广的关键.一种基于设备间接收信号强度(Received Signal Strength,RSS)相关性的位置指纹室内定位方法被提出.以智能手机为用户终端,离线阶段,通过智能手机扫描的Wi-Fi信号强度信息,经过数据处理,筛选稳定的接入点(Access Point,AP),构建离线指纹数据库;在线定位阶段,对于实时获取的Wi-Fi信号强度信息,进行筛选处理后,挑选与离线指纹共同拥有的AP,并根据该AP集合,形成新的离线指纹和在线指纹.对离线指纹按RSS的大小降序排序;在线指纹,则以同一次序对RSS排序,然后利用皮尔逊相关系数和杰卡德相似系数,计算指纹相似度并排序,通过K最近邻(K-Nearest Neighbor,KNN)算法实现用户定位.实验表明该方法可有效解决设备差异性问题,并实现精确定位,平均定位误差达到1.7 m.     

基于RSSI的Wi-Fi室内定位常用算法对比

WiFi定位是室内定位的方法之一,其观测值主要为WiFi的信号强度(received signal strength indication,RSSI),利用信号强度进行室内定位的方法基本上可以分为两种,一种根据模型计算接收节点与发射节点的距离,估计接收节点的位置;另一种是根据事先采集的信号强度指纹进行空间匹配。通过在不同场景下对两种定位算法的比较,基于信号强度指纹匹配的定位精度明显高于基于估计接收节点的定位精度,但与指纹匹配法相比,位置估计法更加灵活。     

基于压缩感知信号重构的wifi室内定位算法研究

针对位置指纹定位算法在训练阶段信号数据采集量大和定位精度不高的问题,提出一种压缩感知(CS,Compressed Sensing)与K均值改进支持向量机(SVM,Support Vector Machine)相结合的定位算法模型(CS-KSVM)。CS算法在训练阶段利用已采集到的部分参考点wifi信号强度数据对整个指纹信号库进行重构以降低信号采集工作量,再用K均值改进SVM算法来实现测试点的准确分类。实验仿真结果表明,CS-KSVM算法在相同采样点条件下的定位精度明显要高于传统定位算法,同时在相同定位精度条件下大大减少了定位需要的采样点数。CS-KSVM算法在3米之内的定位准确度可以达到93.2%。     

基于最小三角形算法的室内可见光三维定位方法

为进一步提高室内可见光三维定位的精度，提出了一种基于最小三角形算法的室内可见光三维定位方法。该方法采用视距链路模型，由定位终端接收携带发光二极管位置信息的光强信号，利用最小三角形算法和接收信号强度指示方法来计算接收机在室内的三维位置信息，再引入加权质心算法降低光路受遮挡所造成的影响。仿真结果表明：在室内5 m×5 m×3 m的定位区域内，提出的定位方法平均定位误差约为4.35 cm，平均高度误差约为1.65 cm，定位精度优于传统的室内可见光三维定位方法。     

一种基于RSSI的权重值选择及加权定位算法

提出了一种基于Wi-Fi网络的接收信号强度指示(RSSI)的权重值选择及加权定位算法。该算法在离线阶段为每个接入点(AP)在每个参考位置点的RSSI设定了变化区间;在定位阶段,将扫描到的每个AP的RSSI落在该区间的所有位置点的权重值加1,然后采用加权算法计算定位目标的估计位置。实验证明,该算法减少了RSSI随机变化引起的定位误差,能获得较好的定位精确度。     

基于指纹的室内可见光定位方法

为了实现低成本、低复杂度以及高精度的室内定位系统,提出了基于指纹的室内可见光定位方法。该方法利用可见光发光二极管作为信号源,根据接收到的可见光信号强度信息,结合三角定位算法和指纹定位算法,实现室内高精度定位。定位过程主要分为两步:第一步,通过三角定位算法确定移动目标粗略的位置范围;第二步,以该位置范围作为限制条件,使用指纹定位算法实现更精确定位。实验结果表明,该方法与传统的基于可见光信号强度的定位方法相比,平均定位精度提高了64.71%;同时,与传统的基于指纹的定位方法相比,可以在更低复杂度的情况下,实现更精确定位。     

基于RSSI的井下人员定位算法改进

在无线传感器网络中，针对接收信号强度指示(Received Signal Strength Indication, RSSI)在煤矿井下长距离巷道内信号衰减快、测距精度偏差大等问题，提出了一种基于RSSI的高斯滤波加权质心定位算法。采用高斯滤波对采集的RSSI值进行修正，一定程度上减轻环境造成的影响。将RSSI测距算法与改进加权质心算法相结合，得出待测节点坐标位置。仿真试验表明，该改进算法与原有定位算法相比，定位误差明显降低，可基本满足煤矿井下人员的安全生产和定位需求。     

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.