磁保持射频继电器在移动通信设备自动测试系统中的应用研究

介绍了磁保持继电器的原理和移动通信设备自动测试系统的体系结构,重点阐述了磁保持射频继电器在直放站自动测试系统中的应用方法,并提出了使用磁保持射频继电器提高自动测试系统的安全性,防止意外损坏射频程控仪器的新方案和相应的软硬件设计.该方案在实际自动测试系统中已得到成功应用。     

A H-QoS-demand personalized home physiological monitoring system over a wireless multi-hop relay network for mobile home healthcare applications

For the elderly and chronic patients with cardiovascular disease who live alone, it is necessary to constantly monitor their physiological parameters, especially the electrocardiogram (ECG), to effectively prevent and control their health condition and even to provide urgent treatment or care while an emergency such as the abnormal variation of heart rate (HR) occurs. In this paper, a wireless in-home physiological monitoring system, based on multi-hop relay communications, which can ubiquitously and continuously monitor the patient's ECG at any time or any place at home without space limit and the “dead spot” due to the extended communication coverage by multi-hop wireless connectivity, is proposed. The system consists of a mobile-care device, which is responsible for capturing and wirelessly sending the patient's ECG data, a wireless multi-hop relay network (WMHRN) that is in charge of relaying the data sent by the former, and a residential gateway (RG), which is responsible for gathering and uploading the received ECG data to the remote care server through the Internet to carry out the patient's health condition monitoring and the management of pathological data. However, in order to assure that the ECG data can be effectively and timely forwarded, from the mobile-care device to the RG through the WMHRN, to meet the healthcare quality of service (H-QoS) demand for reliable and real-time end-to-end ECG transmission, the analysis of WMHRN latency in data-forwarding stage and the deployment consideration of wireless relay nodes are investigated in detail in this work. Moreover, an emergency alert service using short message service (SMS), based on the detection of abnormal variation of HR, is also used in the RG to further enhance the healthcare service quality. A prototype of this system has been developed and implemented. Finally, the experimental results are presented to verify the feasibility of the proposed system.     

特征模型方法在中继星天线指向控制中的应用

主要研究基于特征模型的自适应控制方法在中继星天线指向跟踪控制中的应用.利用由Newton-Euler方法建立的挠性多体卫星的混合坐标方程动力学简化模型进行数学仿真,分别采用基于特征模型的自适应控制方法和经典PID方法进行卫星本体姿态和天线指向跟踪控制,并比较两种控制方法的控制稳定性和控制精度,仿真结果表明用特征模型自适应控制方法设计的控制器能满足系统性能要求,并具有很强的鲁棒性和抗干扰性.     

基于超程时间测量的电磁继电器故障检测

针对现有电磁继电器隐性故障检测率较低的问题,提出一种基于超程时间测量的电磁继电器故障检测方法。首先,通过离线优化获取最优模糊阈值,然后应用线性回归方法,对超程时间监测数据进行在线预测,并利用拟合误差将预测值扩展为预测区间;其次,根据最优模糊阈值,将监测数据和预测区间分别转换为当前和预测故障证据,利用区间证据推理迭代融合积累、当前、预测3种故障证据,获取更新后的积累故障证据;最后,按照故障判据,由积累故障证据得到继电器故障检测结果。所提方法充分考虑了继电器隐性故障的渐变性特征以及超程时间测量过程所包含的不确定性,使故障证据更贴近于继电器实际工况。实验结果表明,与现有方法相比,所提方法在证据准确性和收敛速度上具有显著优势,能够有效提升电磁继电器隐性故障的检测精度。     

海上风电交流送出线路继电保护优化设计

针对海上风电运行环境恶劣、平台面积资源有限以及电缆线路电容电流显著等问题,提出一种适用于海上风电送出线路的高压线路保护与电抗器保护一体化设计的新方案。首先,将输电线路和电抗器视为一个电气设备,设计了集成优化整体方案,避免了传统的电抗器支路电流的迭代计算。然后,对比研究了传统差动和行波差动对电缆线路电容电流的补偿效果,提出了线路保护优化处理技术。通过引入更为适合的线路零序电流作为电抗器零序差动的制动电流,提出了电抗器保护功能优化策略。最后,仿真实验验证了所提的优化处理技术能够提高海缆线路差动保护和电抗器零序差动保护的灵敏性和可靠性。     

A fixed clustering protocol based on random relay strategy for EHWSN

In Energy Harvesting Wireless Sensor Networks (EHWSN), the communication protocol will directly affect the final performance of the network, so it is necessary to study the communication protocol based on EHWSN. In this paper, for the low-cost fixed clustering problem, a fixed clustering protocol RRCEH is based on random relaying. Our proposed RRCEH abandons the inefficient inter-cluster communication method of the traditional fixed clustering protocol. To coordinate the data upload of the cluster head, RRCEH allocates different random relay vectors to each ring area of the network, and combines all the random relay vectors into a random relay matrix of RRCEH. In each communication round, the cluster head node randomly selects its relay target node to send data according to the probability distribution in the random relay vector in the area. For two different cluster head configuration scenarios, by optimizing the random relay matrix, RRCEH can effectively reduce the network's configuration requirements for cluster head energy harvesting capability, thus reducing the deployment cost of EHWSN.     

重载电力牵引系统馈线保护及故障点测距苦干问题与对策

本文分析了重载电力牵引供电系统在机车再生制动、机车过电分相等运行工况及接触线／正馈线断线接地故障时,馈线保护的动作行为,提出了一种自适应距离继电器。同时分析了目前ＡＴ供电系统采用的“ＡＴ中性点吸上电流比”原理的故障测距装置在经济性、可靠性、适用性和精确性等方面的不足,介绍了一种新型的故障点测距装置。     

A test of the fail-safe N for self-help programs.

A meta-analysis of published studies on the clinical efficacy of selected self-help programs (F. Scogin et al; see record 1990-15222-001) indicated that such conditions were more effective than no-treatment controls. Calculation of a fail-safe N showed that 53 nonsignificant studies would have to exist to render the conclusions of the meta-analysis invalid. Results indicate that unpublished research is unlikely to threaten the validity of the original meta-analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

矿区35kV电网线路继电保护的现状及改进措施

分析了矿区35 kV电网线路继电保护的现状,指出存在的主要问题是保护定值整定、上下时限配合困难,容易引起保护拒动、越级跳闸等故障;提出了采用先进的数字式继电保护装置、采用输电线路纵联保护、增加低电压闭锁保护、加装故障录波装置等线路继电保护改进措施,并通过GPRS分布式故障录波报警系统在矿区电网线路继电保护中的应用实例说明了采用先进的技术装备可提高矿区电网继电保护的可靠性和电网运行的安全稳定性。     

基于继电保护测试仪的数据存储设计

为解决便携式继电保护测试仪在数据处理及存储方面的相关问题,提出基于USB芯片CH375的解决方案。通过分析CH375的命令集和工作时序,编写了MSP430处理器与U盘的数据通信应用程序。使用结果表明,由此构建的USB接口能够与各种U盘进行数据高速传输和存储。