Modeling wireless fading channels via stochastic differential equations: identification and estimation based on noisy measurements

This paper is concerned with modeling and identification of wireless channels using noisy measurements. The models employed are governed by stochastic differential equations (SDEs) in state space form, while the identification method is based on the expectation-maximization (EM) algorithm and Kalman filtering. The algorithm is tested against real channel measurements. The results presented include state space models for the channels, estimates of inphase and quadrature components, and estimates of the corresponding Doppler power spectral densities (DPSDs), from sample noisy measurements. Based on the available measurements, it is concluded that state space models of order two are sufficient for wireless flat fading channel characterization.     

One-to-Many and Many-to-One Optical Chaos Communications Using Semiconductor Lasers

A theoretical construction of one-to-many (OTM) and many-to-one (MTO) chaos synchronization communications using semiconductor lasers is presented. One center laser provides strong injections (strong link) to other side lasers, and the side lasers also provide weak injections (weak link) to the center one. Simulation results show that the side lasers synchronize with the center laser through injection-locking. In addition, messages transmitted via the strong links or the weak links experience strong chaos pass filtering, enabling us to realize OTM and MTO communications.     

基于MoCA标准的家庭网络研究

本文描述了一种基于MOCA标准的家庭网络,并对该网络及设备进行了基本性能的测试.本文首先介绍了家庭网络的发展现状,对目前的各种家庭网络标准进行了比较.在此基础上详细描述了基于MOCA标准的家庭网络,并对该网络的设计,实现、网络性能进行了详述.然后对该网络进行了测试并得出了相关的测试结论.最后指出该网络的不足及改进之处.     

基于m法线性有限元分析在桩基计算中的应用

针对目前各类有限元软件在工程设计中的应用已相当普遍,提出了通过有限元模型解决桩基的强度验算和水平位移的计算,不仅使桩的设计变得简单,而且还可在相当的精度内考虑桩基和上部结构的共同作用。     

农村通自来水工程若干技术问题初探

根据在农村通自来水工程实践中积累的经验,提出并较好地解决了农村供水工程的评价标准,设计供水时间的确定,输配水管网设计中的优化等问题,对建好、管好和用好农村自来水工程具有一定的帮助作用.     

建筑物下采煤方法设计

论文针对了北掌矿井井田范围建(构)筑物多、压煤严重等特点,在分析比较充填开采和条带式开采等"建下"开采方法的技术上,确定了比较适合该矿的冒落条采法开采技术,指出新建矿井以建筑物下开采为主也可获得较好的经济社会效益。在此基础上,对条采工作面长度,保留煤柱宽度及主要指标进行了设计。     

Optimal and self‐tuning fusion Kalman filters for discrete‐time stochastic singular systems

Based on the optimal fusion estimation algorithm weighted by scalars in the linear minimum variance sense, a distributed optimal fusion Kalman filter weighted by scalars is presented for discrete‐time stochastic singular systems with multiple sensors and correlated noises. A cross‐covariance matrix of filtering errors between any two sensors is derived. When the noise statistical information is unknown, a distributed identification approach is presented based on correlation functions and the weighted average method. Further, a distributed self‐tuning fusion filter is given, which includes two stage fusions where the first‐stage fusion is used to identify the noise covariance and the second‐stage fusion is used to obtain the fusion state filter. A simulation verifies the effectiveness of the proposed algorithm. Copyright © 2008 John Wiley & Sons, Ltd.     

生物质合成气一步法合成二甲醚的研究

用共沉淀沉积法制备了生物质合成气直接合成二甲醚(DME)的催化剂,考察了固定床中温度、压力、空速等工艺条件对二甲醚合成性能的影响,同时基于Gibbs自由能最小法对合成DIME反应的化学平衡进行模拟计算,并与实际测试结果相比较.结果表明,模拟结果与测试结果吻合较好.     

镍氢电池负极用低成本储氢合金的研究

研究了ABS型储氢合金在低Co含量条件下，随B组元替代元素Co，Al，Si等含量的变化对合金电化学性能的影响规律，同时研究了A组元中不同La／Ce比对合金电化学性能的影响情况。结果表明，随合金中Co含量的降低，合金的活化性能和放电容量得以改善，但合金的循环寿命下降也比较明显；在试验范围内，随Al元素的加入，合金的循环寿命得以改善，但材料的放电容量和活化性能均有所下降；随合金La／Ce比的降低，合金的放电容量略有下降，但其循环寿命和放电电压平台有较大提高。     

钢包钢水保温覆盖剂的开发

研制了钢包钢水新型保温覆盖剂，主要成分为（%）；15-25C，20-35SiO2,10-20Al2O3,2-5Fe2O3,15-25CaO,2-5MgO，新覆盖剂铺展性与保温性能良好。经转炉钢水160t钢包生产使用，统计数据表明，镇静15min后钢水降温速度由原碳化稻壳覆盖剂1.33℃/min降低到0.93℃/min。