双中心节点的网络软RAID系统的设计与实现

随着计算机技术与网络技术的快速发展,基于网络的分布式存储逐渐成为研究的重点,通过网络提供方便、可靠与大容量的存储服务成为可能。该文设计并实现了双中心节点的网络软RAID系统,并对系统结构、工作原理和技术要点进行了详细介绍。     

综合布线系统

综合布线是近年发展起来的一种布线技术,其核心思想是采用星型拓扑结构的模块化设计,以达到快捷的路由配线和简便的设备扩充。综合布线系统的质量直接影响着网络系统的性能。本文重点阐述了综合布线的基本原理及施工具体要求。     

CFOSAT散射计几何定位验证与精度初步评估

采用STK软件对中法海洋卫星（CFOSAT）散射计几何定位算法进行了验证。针对CFOSAT散射计扇形波束扫描观测体制,分别就扇形波束扫描散射计几何定位原型算法、包含天线安装误差的完整几何定位算法利用STK进行了详细验证。结果表明了CFOSAT扇形波束散射计几何定位算法的准确性,与STK几何定位结果偏差在100 m以内。在此基础上,结合有源定标器实验数据,对CFOSAT实际观测数据几何定位参数进行了校正,给出了CFOSAT散射计几何定位精度的初步评估。     

分布式天基空间监视雷达编队构形

为克服地基观测系统时空监视能力的限制,提出分布式天基空间监视雷达编队的定位原理,并在平均定位误差最小的意义下对三星编队构形进行设计。其主雷达采用收发的工作方式,而2颗辅助雷达只进行接收。三星的几何布局在轨道运行过程中为动态变化,变化过程由三星构形决定。     

不同载噪比条件下误码性能测试分析

基于IDR／IBS体制,从诸多参数的概念入手,分析卫星通信中栽噪比、信噪比与误码率的关系,以及如何利用频谱分析仪准确测量接收卫星信号的载噪比。测试分析结果表明：不能为降低误码率而刻意提高（C0＋N0）／N0,必须经过认真的测试调整,寻求最佳值。     

基于IMS的下一代网络

IMS（IP多媒体子系统）是目前业界公认实现FMC（固定移动网络融合）的最佳途径,详细阐述了IMS的标准化进程、体系架构。并介绍了IMS的技术特点。     

A band-ratio algorithm for retrieving open-lake chlorophyll values from satellite observations of the Great Lakes

The U.S. Environmental Protection Agency's Great Lakes National Program Office (GLNPO) has collected water quality data from the five Great Lakes annually since 1993. We used the GLNPO observations made since 2002 along with coincident measurements made by the Sea-viewing Wide Field-of-View Sensor (SeaWiFS) and the Moderate-resolution Imaging Spectroradiometer (MODIS) to develop a new band-ratio algorithm for estimating chlorophyll concentrations in the Great Lakes from satellite observations. The new algorithm is based on a third-order polynomial model using the same maximum band ratios employed in the standard NASA algorithms (OC4 for SeaWiFS and OC3M for MODIS). The sensor-specific coefficients for the new algorithm were obtained by fitting the relationship to several hundred matched field and satellite observations. Although there are some seasonal variations in some lakes, the relationship between the observed chlorophyll values and those modeled using the new coefficients is fairly stable from lake to lake and across years. The accuracy of the satellite chlorophyll estimates derived from the new algorithm was improved substantially relative both to the standard NASA retrievals and to previously published algorithms tuned to individual lakes. Monte-Carlo fits to randomly selected subsets of the observations allowed us to estimate the uncertainty associated with the retrievals purely as a function of the satellite data. Our results provide, for the first time, a single simple band ratio method for retrieving chlorophyll concentrations in the offshore “open” waters of the Great Lakes from satellite observations.     

卫星地面试验系统半物理仿真通信机制研究

以实际卫星项目的研制过程为基础,对卫星地面试验系统中的半物理仿真通信进行了研究.给出了具有数据保障和同步机制的通信方案,实现了在含有通信机制的半物理仿真环境下的卫星通信软件框架,实现了数据的中断实时收发,保证了数据正确有效传输.半物理仿真阶段,将实际的电器接口和硬件通信机制引入到模型仿真之中,采用与卫星上相同的软硬件接口,运行相同的星上协议,可以在这个阶段进行实际卫星上大部分软件的设计,保持软件系统的稳定性和可移植性.     

3G底层核心实时状态检测模块的设计

本文首先提出了3G底层技术统一平台的概念,介绍了本平台及系统控制子系统的框架结构;然后给出了实时状态检测模块的功能和结构设计,包括其在整个系统中的位置、和其它功能模块的联系等;进而重点分析了该模块各个进程和任务的处理流程,并对它们是如何分工合作、实现对整个底层工作状态的实时性检测和控制等技术做了详细说明.     

A method for estimating direct normal solar irradiation from satellite data for a tropical environment

In order to investigate a potential use of concentrating solar power technologies and select an optimum site for these technologies, it is necessary to obtain information on the geographical distribution of direct normal solar irradiation over an area of interest. In this work, we have developed a method for estimating direct normal irradiation from satellite data for a tropical environment. The method starts with the estimation of global irradiation on a horizontal surface from MTSAT-1R satellite data and other ground-based ancillary data. Then a satellite-based diffuse fraction model was developed and used to estimate the diffuse component of the satellite-derived global irradiation. Based on this estimated global and diffuse irradiation and the solar radiation incident angle, the direct normal irradiation was finally calculated. To evaluate its performance, the method was used to estimate the monthly average hourly direct normal irradiation at seven pyrheliometer stations in Thailand. It was found that values of monthly average hourly direct normal irradiation from the measurements and those estimated from the proposed method are in reasonable agreement, with a root mean square difference of 16% and a mean bias of −1.6%, with respect to mean measured values. After the validation, this method was used to estimate the monthly average hourly direct normal irradiation over Thailand by using MTSAT-1R satellite data for the period from June 2005 to December 2008. Results from the calculation were displayed as hourly and yearly irradiation maps. These maps reveal that the direct normal irradiation in Thailand was strongly affected by the tropical monsoons and local topography of the country.