Satellite UMTS/IMT2000 W-CDMA air interfaces

The third-generation IMT-2000 initiative of the International Telecommunication Union is aiming at the provision of a limited family of global standards providing worldwide multimedia wireless services in a host of environments encompassing indoor picocells to satellite megacells. The ITU IMT-2000 initiative has been supported by several regional standardization bodies such as the European Telecommunication Standard Institute with its Universal Mobile Telecommunication System. In this article a few air interface proposals for the satellite component of UMTS/IMT-2000 based on adaptation of the emerging terrestrial wideband CDMA standards are reviewed. In particular, S-UMTS requirements are examined together with W-CDMA applicability to the satellite environment. It is shown that with minor adaptations, the terrestrial W-CDMA air interface provides an efficient solution for the satellite UMTS component. This commonality will certainly help in the realization of low-cost low-size dual-mode user terminals encompassing both terrestrial and satellite components     

Modeling and Interoperability Test Case Generation of a Real-Time QoS Monitoring Protocol

QoS monitoring is a kind of real-time systems which allows each level of the system to track the ongoing QoS levels achieved by the lower network layers. For these systems, real-time communication between corresponding transport protocol objects is essential for their correct behavior. When two or more entities are employed to perform a certain task as in the case of communication protocols, the capability to do so is called interoperability and considered as the essential aspect of correctness of communication systems. This paper describes a formal approach on modeling and interoperability test case generation of a real-time QoS monitoring protocol. For this, we specify the behavior of flow monitoring of transport layer QoS protocol, i.e., METS protocol, which is proposed to address QoS from an end-to-end's point of view, based on QoS architecture model which includes ATM network in lower layers. We use a real-time Input/Output Finite State Machine to model the behavior of real-time flow monitoring over time. From the modeled real-time I/OFSM, we generate interoperability test cases to check the correctness of METS protocol's flow monitoring behaviors for two end systems. A new approach to efficient interoperability testing is described and the method of interoperability test cases generation is shown with the example of METS protocol's flow monitoring. The current TTCN is not appropriate for testing real-time and multimedia systems. Because test events in TTCN are for message-based system and not for stream-based systems, the real-time in TTCN can only be approximated. This paper also proposes the notation of real-time Abstract Test Suite by means of real-time extension of TTCN. This approach gives the advantages that only a few syntactical changes are necessary, and TTCN and real-time TTCN are compatible. This formal approach on interoperability testing can be applied to the real-time protocols related to IMT-2000, B-ISDN and real-time systems.     

TFT-LCD技术的研究进展与发展趋势

介绍了近年来世界ＴＦＴ ＬＣＤ技术的研究现状,论述了未来ＴＦＴ ＬＣＤ技术的发展趋势     

阵列双稳随机共振在微弱信号检测中的应用研究

阵列双稳随机共振(stochastic resonance, SR)系统可利用噪声在单个双稳SR系统基础上进一步增强微弱信号检测的能力,为强噪声背景下微弱信号的检测开创了新方法。本文应用阵列双稳SR原理进行微弱信号检测的研究,采用理论和数值仿真相结合,通过稳态自协方差函数,分析了阵列双稳SR系统输出信噪比（signal-to-noise ratio, SNR）增益。在此基础上,分别讨论了阵列噪声、外部噪声及阵列单元数对检测性能的影响。并与单个双稳SR检测弱信号进行性能比较,分析和仿真结果都表明,在相同条件下,采用阵列双稳SR比采用单个双稳SR检测微弱信号性能有较大改善。这些研究结果对于阵列双稳SR的进一步发展及应用具有重要意义。      

基于KPCA和类峰值特征的模拟电路诊断方法

针对传统的核主成分分析方法(KPCA)无法解决在故障样本交叠严重时多分类性能较差的问题,提出一种基于改进KPCA的特征提取和类峰值特征辅助识别分类相结合的模拟电路故障诊断方法.在预处理阶段,提出了一种图像混合欧氏距离用于建立核函数,进行核主成分分析特征提取,克服了传统KPCA的局限性;并且设计了一种用类峰值特征识别的方...     

宫腔镜检查在不明原因复发性自然流产中的应用

目的：部分复发性自然流产病因不明确,本研究通过宫腔镜检查,探讨宫腔镜在不明原因复发性自然流产中的病因诊断作用。方法：对2008年1月至2010年1月在我院就诊的原因不明的复发性自然流产患者38例行宫腔镜检查,并取内膜活检。结果：38例患者中,宫腔镜检查4例有轻度宫腔粘连,4例子宫内膜有炎症表现,病理诊断确诊5例有慢性子...     

基于三维分层图模型的复杂情况下多运动目标跟踪

复杂情况下的多运动目标跟踪是视频监控中的关 键问题,在多目标运动中相互遮挡时二维视觉信息容易丢失而造 成无法准确跟踪识别目标。本文采用kinect摄像机获取三维视觉信息,从节点、边、空间结 构三个层次上建立目标的三维分 层图模型表征目标的三维特征,并在每层进行通过视频帧间的匹配从而获得三维分层图模型 匹配结果,并根据匹配结果先初 步分析目标跟踪情况,如发生遮挡则通过遮挡区域聚类块与三维分层图模型中各特征匹配确 定其匹配结果,从而得到多运动 目标在复杂运动情况中的跟踪结果。实验表明,在实验室kinect拍摄的视频序列上当目标出 现遮挡等复杂情况,也能取得较 好的跟踪结果,在实验视频中比经典方法的跟踪总体性能指标改善约3%,说明本方法能较好 地实现复杂情况下的多运动目标跟踪。     

基于OSGI的智能家庭系统的设计与实现

为了解决普适环境下智能家庭各类设备组网困难的问题,本系统采用OSGi(Open Service Gateway Initiative)服务框架和LonWorks现场总线技术,利用低压电力线载波手段来设计和实现智能家庭系统.利用上述方法可以极大地实现不同标准设备的组网,并且可以实现对智能家庭设备管理的灵活性和便捷性.     

Sintering of Inkjet-Printed Silver Nanoparticles at Room Temperature Using Intense Pulsed Light

Intense pulsed light (IPL) was used to sinter printed silver nanoink patterns consisting of 20-nm to 40-nm silver nanoparticles dispersed in diethylene glycol (DEG). Three consecutive pulses at 50 J/cm² in less than 30 ms was sufficient to adequately sinter silver nanoink patterns for printed electronics without degradation of the substrates. This is an exceptionally short time compared with that of the conventional thermal sintering process. On the sintered conductive silver patterns, neck-like junctions between nanoparticles were observed using scanning electron microscopy (SEM). The melting temperature, 194.1°C, of silver nanoparticles was found using differential scanning calorimetry (DSC). Also, x-ray diffraction (XRD) was used to find the grain size of the printed silver nanoink patterns. The IPL-sintered silver pattern had a grain size of 86.3 ± 7.2 nm. From this work, it was found that the IPL-sintered silver pattern had a low resistivity of 49 ± 3 nΩ m, which is low enough to be used for printed electronics.     

基于方形腔耦合金属波导结构的全光等离子体开关

提出了一种新型的方形腔耦合金属波导结构,该结构由两个相互平行的矩形金属波导和一个内嵌可连通的方形谐振腔构成。利用方形谐振腔局域表面等离子体实现带阻滤波特性,并通过多路复用实现双端口全光等离子体开关。采用时域有限差分方法(FDTD)研究了方形腔的边长、折射率和谐振距离对强透射特性的影响。结果表明,基于方形腔耦合金属波导结构的光开关在工作中具有较好的阻带特性和透射特性,其最大透射率可达92%,最小阻带透射率达0.2%,工作波长范围为607~785nm。