基于SLA的网格监控体系GSLMA及其实验床

从体系结构的角度出发,将现有网格监控工具分为3类,对每一类网格监控结构进行了分析 和对比,并提出了一种基于服务级别协定SLA(Service Level Agreement)的网格服务监控体系结构GSLMA(Grid Service Level Monitoring Architecture).GSLMA采用基 于面向服务的体系结构SOA(Service Oriented Architecture)的松散耦合结构,通过动态部 署解决了对新增服务的监控扩展,并提供第三方的监控功能,是一个具有高灵活性和高可伸 缩性的网格监控体系结构.最后,介绍了实现GSLMA实验床中的关键技术,包括:对开放网格 服务体系结构OGSA(Open Grid Service Architecture)容器进行扩展,采用Web服务级别协定WSLA(Web Service Level Agreement)解决被监控服务信息的统一描述等等.      

基于扭矩特性的航空发动机起动系统数学模型

简述了起动过程,分析了起动过程中起动扭矩与发动机扭矩及其负载扭矩特性间的关系,给出了起动机的选择原则,从而建立了基于起动机扭矩及发动机扭矩特性的发动机起动系统数学模型,并给出起动时间的计算方法。最后以典型发动机起动系统作为仿真实例验证了此方法的可行性。      

俄罗斯标准化的变革与发展

简要叙述俄罗斯标准化的发展历史,分析俄罗斯标准化的现状。同时,着重对俄罗斯新出台的《技术调节法》进行了介绍。     

我校大学生心理健康状况不容乐观

本文用SCL-90症状自评量表方法,对我校三个年级的部分班级进行了测查.分析表明我院大学生的心理健康状况不容乐观.本文还对学生管理现状提出了进一步改进建议.     

数字式频分多路遥测系统副载波解调器的设计

提出一种新的数字式频分多路遥测系统副载波解调器的设计方案。详细论述该数字式解调器的工作原理和关键技术 ,并给出硬件设计方案。该系统的特点是 :灵活性强 ,易与计算机相结合构成数字式 FM- FM遥测数据处理系统。     

液氧／煤油补燃火箭发动机氧路低频动特性分析

液体火箭发动机氧路系统低频动特性研究是进行运载火箭POGO振动分析和判别的必要工作。以某型液氧／煤油补燃循环火箭发动机为研究对象,采用模块化建模方法建立了基于自动控制理论的发动机氧路系统线性小偏差的传递矩阵模型,分别对发动机氧路系统和试车台氧化剂输送系统动特性进行数值仿真,并对比分析了试车数据和仿真结果。研究表明,数学模型和计算方法具有一定的正确性;熵波对系统的低频动特性有一定影响。     

航天器遥控FPGA片上容错设计技术研究

结合深空探测项目研制任务研究遥控数据接收处理电路FPGA片上容错设计技术。在研究航天器遥控数据接收处理电路数据模型的基础上,提出遥控数据接收处理电路FPGA片上小粒度自主备份容错设计方法;应用此新方法进行遥控指令通道FPGA设计优化;针对FPGA缺陷成团性,进行遥控指令通道FPGA布局优化,最终设计出能够自主容错,容错能力更强,可以应对缺陷成团性影响的新一代遥控指令通道FPGA。这一FPGA的实现,验证了文中提出的新方法,也为未来深空探测项目、微小卫星等提供新的遥控产品。     

遥测系统再认识

遥测系统是闭环系统,不是惯称的开环系统。与控制系统相比,遥测系统具有三大特点:测量信息源的不确定性;反馈通道与主通道的相关性;系统误差主要源于主通道。研究并获取系统传递函数是系统设计的重要内容,而机理分析和系统辨识正是适合该需求的有效措施。     

Minimum of PDOP and its applications in inter-satellite links (ISL) establishment of Walker-δ constellation

Within the next decade, there will be a number of GNSS (Global Navigation Satellite System) available, i.e. modernized GPS, Galileo, restored GLONASS, BeiDou and many other regional GNSS augmentation systems. Thus, measurement redundancies and geometry of the satellites can be improved. GDOP (Geometric Dilution of Precision) and PDOP (Position Dilution of Precision) are associated with the constellation geometry of satellites, and they are the geometrically determined factors that describe the effect of geometry on the relationship between measurement error and position error. GDOP and PDOP are often used as standards for selecting good satellites to meet the desired positioning precision. In this paper, the related conclusions of minimum of GDOP which was discussed are given, and it is used to study the minimum of PDOP for two cases that the receiver is on the earth’s surface and the receiver is on satellite. The corresponding theorem and constructive solutions of minimum of PDOP are given. Then, the rationality of the ISL (inter-satellite link) establishment criteria in Walker-δ constellation is discussed by using the theory of minimum of PDOP. Finally, the minimum of PDOP is calculated when the number of satellites is 4–10, and these results are verified by using Monte Carlo method.     

Novel radar target detection

Herein, a novel method of radar target detection based on 2-dimensional (2-D) fractal dimension is proposed. The proposed approach exploits both range information and azimuth information to estimate fractal dimension. Moreover, the approach can increase the number of data points. The above two merits result in the fractal dimension estimated by this method are more accurate and robust than the previous method. The detection performance is also better than the previous, which only makes use of 1-dimensional (1-D) information to estimate fractal dimension. Theoretical analysis and experimental results show that the proposed method performs well in a strong clutter background. The proposed method is also validated by real-life radar data, and the better result has been achieved.