青藏铁路综合安全实时监测平台技术方案研究

分析了在青藏铁路特殊环境下综合安全实时监测平台应具备的功能,构建了该平台的体系架构.分析了平台对于实时数据的闭环处置流程,给出了平台建设的技术实现要点.综合安全实时监测平台的建设将为青藏铁路公司各相关部门或领导建立一个综合性的全面的公司运营安全情况视图,为领导的决策、安全管理及综合性维护等提供依据.将形成较为完整的铁路运营安全保障体系,实现对各类安全监控信息资源的综合、高效利用,填补高原铁路综合监控技术的空白.     

Safety assessment of the NET Predesign

Work carried out by European Associations on Safety and Environment inside the EC Fusion Technology Programme and by NET has been concentrated on safety-related guidance and on safety assessment of the NET Predesign. Emphasis has been put on analysis of accident sequences of regulatory concern up to worst case accidents, including quantification of consequences to components, systems, and plant, and of doses to the public. Probabilistic safety studies for the most important systems and broadly for the entire plant have been performed to supplement the calculated accidental doses by expectation values for their occurrence rate, and to check the relevance of the reference accident sequences selected initially by judgment. Waste masses per year of operation and for decommissioning have been quantified. For two countries and according to the practices and regulations of these countries, volumes of radioactive waste packaged for final disposal have been determined.Presented at the IAEA Technical Committee Meeting on Developments in Fusion Safety, Toronto, June 7–11, 1993.     

Adaptive prescribed time control for quadrotor formation with stochastic links failure

The formation control for multiple quadrotors subject to maintaining the formation configuration and collision avoidance in the situation of stochastic links failure is investigated in this paper. First, the distributed formation controller is designed, the position controller is developed to manage the desired formation of position, and the attitude controller is developed to control the translation and rotation movements of the quadrotor. Then, in order to avoid the collisions between multiple quadrotors and the obstacles, a potential energy function method is introduced into the quadrotor formation control combined with the nest adaptive control. Inspired by the design of event trigger controller, a communication compensation controller is designed to ensure the stability of quadrotor formation under the condition of random communication interruption and recovery. Moreover, a prescribed time function is designed, which means the convergence time of the formation system can be set in advance. The prescribed time stability of the formation control system is proved by Lyapunov theory. Finally, the simulation results verify the effectiveness and superiority of this method.     

EPA功能安全协议的研究与实现

现场总线在通信传输过程中,会受到各种通信故障的影响,而现场总线与功能安全的结合可降低这种影响。该文描述EPA功能安全通信模型,针对通信传输过程中可能出现的通信错误,采用时间戳、序列号、CRC校验等功能安全通信技术。给出EPA功能安全协议层的报文结构,阐述功能安全协议层的具体实现过程。     

1553B通信协议的可依赖性讨论

1553B是飞机电传系统的通信协议,由于硬件上抗干扰仅考虑了系统内部自生的干扰,实际环境要严重得多;因为只按奇偶位作校验,所以错字漏检的概率比较大;由于回传状态字内容不全面,在漏检错字时会发生假冒错;由于指令字出错不易纠正,最好情况下靠2次重传,丢帧可能性大.漏检错帧和丢帧多会使多重冗余的表决机制失效,也会使网络管理类指令失效,成为潜伏的故障.通过定量分析,确定了一些情况下的失效率,例如假定取CAN,Profesafe同样的误码率ber=0.01时,除去最大值/最小值再取均值时的4冗余系统因错字漏检引起的每小时失效可达2×10-1次.     

Unicast-based fault-tolerant multicasting in wormhole-routed hypercubes

A unicast-based fault-tolerant multicasting method is proposed for hypercubes, which can still work well when the system contains enough faults. A multicast message may be unable to reach a destination if Hamming distance between the destination and the multicast source is large enough. A multicast message fails if any one of the destinations is unreachable from the source. An effective destination ordering scheme of the destinations is proposed for one-port systems first, it is extended to all-port systems for unicast-based fault-tolerant multicasting. Unreachable destinations from the source based on the local safety information are forwarded to a reachable destination, where the multicast message can be routed reliably. Destination ordering is completed based on Hamming distance. A multiple round p-cube routing scheme is presented for a deadlock-free fault-tolerant routing for each unicast step in hypercubes, where the same virtual channel is used for each round of p-cube routing. Sufficient simulation results are presented by comparing with the previous methods.     

Towards a Mobile Code Management Environment for Complex,Real-Time,Distributed Systems

We present a novel mobile code management environment,currently under design and development. Our design employs anopen architecture, suitable for ``plug-and-play' with COTS andother groups' tools. While we have studied new algorithms, costand objective functions, and other fundamental issues, the maincontribution of this experimental research work is in the environmentitself. It should be noted that networked platforms, such asthe World Wide Web, are inherently not suitable for traditional,predictable real-time applications. Thus, real-time concernsnecessarily need to be blended with others concerns, and thetarget applications, making use of our environment, will toobe a blend of partially hard real-time and partially (or mostly)soft-real- time ones. The prototype environment will thereforesupport performance-based analysis and management focusing notonly on predictability but also on compilation, efficiency, safetyand other tradeoffs. We have selected the Java language and itsbytecode format as a representation for mobile code as well asa language for our implementation.     

彗星试验在农药安全评价中的应用

彗星试验(Comet assay)，又称单细胞凝胶电泳试验(SCGE)，是一种快速、简便、灵敏的检测单个细胞DNA断裂的新技术，由于其具备其它试验无可比拟的优越性，因此应用前景十分广泛。本文就该技术的原理、操作程序和方法作一介绍，并预测其在农药安全评价中将有广阔的应用前景。     

白河发电隧洞结构安全分析

密云水库白河发电隧洞在0＋104～0＋130、0＋147～0＋159、0＋207～0＋237三段存在设计配筋量不足,后经回填灌浆和固结灌浆处理,在运行过程中发现实际外水压力比设计外水压力小;水轮机导叶关闭时间比设计短,引起的水击比设计高。本文对原设计、施工、加固资料进行了整理,对白河发电隧洞结构安全进行了分析。     

地方中小水利水电工程建设安全工作不容忽视

针对当前地方中小水利水电工程施工中存在的各类安全问题,分析归纳了安全事故产生的原因,提出加强政府监管、规范监理执业行为、加强监理岗前准入制和执法监管力度等解决施工安全问题的措施。