cdma1x无线子系统导频信道功率分配分析

分析了目前联通CDMA网络建设中的主要问题之一——导频功率分配问题。主要介绍了cdma 1x系统的信道类型，以及前向链路信道功率分配原则，并且对导频信道功率与无线网络覆盖和容量之间的关系进行了初步探讨。     

GPRS业务模型和无线网络的研究

根据GPRS业务及业务发展情况，对GPRS业务模型进行深入研究，并对GPRS无线网络进行了更深入的探讨。     

A direct numerical simulation of transition phenomena in a mixed convection channel flow

This study intends to provide an increased understanding of the laminar-turbulent transition phenomena for the buoyancy-assisted heated vertical channel flow during the early transient stage. The spectral method with weak formulation is applied in the direct numerical simulation. Initial disturbances consist of the finite-amplitude two-dimensional TS wave and a pair of three-dimensional oblique waves for the K-type disturbances. The results from the harmonic energy competitions of different wave modes show that for the buoyancy-assisted heated flow, the (k_x=1, k_z=1) or (1,1) and (1,0) modes would gain energy immediately and start to rise at almost the same rate. This phenomenon is different from that of the buoyancy-opposed flow, where the (1,1) mode decays slowly in the beginning until other modes gain enough energy and then it begins to grow quickly and overtakes the (1,0) mode after a short time period. These different transition patterns match with the experimental results that the flow transition is supercritical and subcritical for the buoyancy-assisted and -opposed flows, respectively. Buoyancy-assisted heated flow transition follows the general trend of an isothermal flow in the beginning, but the thermal-buoyant force is crucial in accelerating the instability and also causing notable differences during the subsequent transition process. All of the results for the vortex structures development, kinetic energy budget of the disturbances, flow visualization by tagged fluid particles, and the local temperature fluctuations are consistent in pointing to a clear pattern for the buoyancy-assisted heated flow transition.     

河道冲刷和清水水流河床冲刷率

在冲积河流里。水流条件变化如洪水、水库泄放清水、河道渠化等使挟沙力不饱和引起冲刷，称为河道冲刷。这与水工建筑造成的局部冲刷不同。河道冲刷深度主要决定于冲刷率和冲刷历时。本研究通过对各种泥沙大量实验，证明了河床冲刷率正比于水流提供的冲刷功率并依赖于泥沙粒径和容重，首次提出了冲刷率公式。经验证，该公式可以用于非恒定流输沙和河流洪水冲刷计算。     

光接入网中DWMT调制技术的研究

研究了光纤－电缆调制解调器接入技术的上行信道调制方式，分析了离散小波多音（DWMT）调制与其它调制方式相比所具有的特点和优势，提出了DWMT调制解调器的实现模型，设计了使用DWMT调制解调器的光纤－电缆调制解调器双向传输的系统方案；并对DWMT调制的系统特性进行了计算机仿真分析。仿真结果表明，DWMT调制是一项能有效实用于光纤－电缆调制解调器系统上行信道的技术。     

基于运动矢量的视频图象数字水印算法

数字水印技术是近年发展起来的一种用于数字产品版权保护和真伪性论证的新兴技术。与静止图象相比，视频水印技术要满足盲检的要求。本文根据运动矢量的特征值ρl，提出了一种视频图象水印新算法。实验结果表明，所提出的水印算法简单、快速，能满足视频编码的实时性要求；算法与现有的视频压缩标准有很好的兼容性；水印的提取具有盲检功能，无需原图象；水印的嵌入不影响I帧的图象质量，与嵌入水印前的原压缩图象相比，嵌入水印后的视频图象信噪比损失很小。     

Nonlinear adaptive algorithms for equalisation in mobile satellite communications

This paper considers the equalisation problem in Quadrature Phase-Shift Keying (QPSK) modulated signals which have been distorted by the passage through a transmission channel. The channel is modelled as a Rician fading channel to simulate the behaviour of the transmission channel in the mobile satellite context. The equalisation is treated as the generalisation of the channel behaviour, and some algorithms with the structure of an artificial neural network using the Multilayer Perceptron, Volterra Series and Radial Basis Function are described. Results for the BER performance of typical transversal equalisers, with Square-Root Kalman adaptation algorithm, and algorithms with artificial neural network structure are also reported and evaluated. Improved performance is exhibited by the artificial neural network approaches.     

RAID的存储信道分析

本文从冗余磁盘阵列的信道模型出发，研究各部分组成的理论与技术。文中在给出系统的模型描述之后，着重分析了冗余信息元生与检纠错、数据分割与同步。还研究了系统中的负荷平衡问题，指出了磁盘优化调度的方向。     

控制决策的信息传输

本文讨论了在一条通讯通道上执行基本控制决策的信息传输问题。结果表明当且仅当第一条通道可模拟另一条通道的操作时，则第一条通道在任何情况下比另一条通道都有优势。     

短模型上的明渠非恒定流试验

水工整体模型试验中,明渠非恒定流至今大多被简化为恒定流,而效果有时并不理想。本文指出,只要设置固定式曲线尾门,并有必要的动态量测设备,便可模拟原型非恒定流;即使模型偏短,也能得出比恒定流试验更接近原型的成果。在同一模型上,既做恒定流试验,又进行必要的非恒定流试验,二者相辅相成,必将有助于试验水平的提高。作为例证,本文介绍了泄洪调度导致航道水面波动的一项试验成果,并以岩基冲刷、通航水流条件、围堰过水、河床冲淤等研究课题为例,讨论了采用“短模型非恒定流试验方式”的必要性与可行性。