一种高效的无线移动网络安全协议

无线移动网络具有节点资源受限的特点,为其设计和实现高效而可靠的安全协议很困难。基于可信第三方和fail-safe协议,提出了一种适合于资源受限网络环境的安全协议。利用SVO逻辑对协议的安全性进行了形式化验证。

铁路信号系统安全功能及安全保障措施研究

采用故障树分析方法,选取列车冲突、列车脱轨、相关人员伤亡等3个顶事件,系统分析影响行车安全和乘客安全的危险源。在总结铁路信号系统已实现的安全功能基础上,提出利用信号系统遍布中心、车站、轨旁和车上的完整传感信息,通过专业间协同、车地信息综合集成的方式扩展信号系统的安全功能。面向安全功能扩展,分析信号系统在物理安全、信息安全和功能安全等方面存在的威胁和问题,提出利用物联网、安全云、系统级故障—安全结构等安全保障措施来全方位提升信号系统的安全性。

列控系统安全防护技术模型研究

列控系统是保证高速列车运行安全、有序、高效的关键。随着铁路运输速度的提升,列车运行安全问题成为铁路运输的重中之重,因此有效地控制列车运行系统,实现列车的自动控制,提高运输效率进而保证行车安全就显得十分必要。文章重点论述了列控系统中的安全防护问题,对当前最常用的两种防护模型进行了较全面的研究,在此基础上对列控系统的安全防护问题进行探讨。

基于Petri网的车站预叠加发码建模与仿真

普速铁路站内轨道电路预叠加ZPW-2000电码化技术成为既有线车站改造或新建车站施工采用的主流技术,为普速铁路实现多次提速提供了有效的技术保障和安全屏障。文章通过离散事件系统建模工具Petri网对站内预叠加电码化进行建模与仿真,仿真模拟列车在站内走行过程中预叠加发码过程,实现对电码化安全性的提升。

微机联锁系统体系结构研究

通过对微机联锁体系结构的研究，阐述了微机联锁系统的软、硬件结构及其技术实现手段，提出了一套充分利用现有技术，具备开放型设计和规模化生产的完整的微机联锁系统体系结构。

64D半自动闭塞测试系统开发

根据64D半自动闭塞的技术要求和工作原理,设计出一种新的继电半自动闭塞设备的电子化测试系统,并对其硬件和软件设计作了详细说明,同时对该测试系统代替现有的64D半自动闭塞设备进行探讨。该测试系统的设计遵循"故障—安全"原则,保证了系统的安全性和可靠性。

CAUSALITY DIAGRAM BASED SAFETY ANALYSIS OF MICRO TURBOJET ENGINE

An improved safety analysis based on the causality diagram for the complex system of micro aero-engines is presented.The study is examined by using the causality diagram in analytical failure cases due to rupture or pentration in the receiver of micro turbojet engine casing,and the comparisons are also made with the results from the traditional fault tree analysis.Experimental results show two main advantages：（1）Quantitative analysis which is more reliable for the failure analysis in jet engines can be produced by the causality diagram analysis;（2）Graphical representation of causality diagram is easier to apply in real test cases and more effective for the safety assessment.

Design and Study of a High Security ATM System

Based on the characteristics of ATM system and the special requirement of financial transaction, an overall design of hardware and software structure of ATM was made. For software structure, the pattern of modules and table? drive is adopted to realize the security of financial transaction and the diagnosis of communication fault. A new method, which is based on the application layer, transport layer and network layer, is used for diagnosing communication fault. Supporting both magnetic card and IC card, the system has been put into use in real financial systems, and has brought about both economic and social effects.

Analysis on produce mechanism and influence factor of CO gas on the coal exploitation working face

Summarized the four main sources of CO gas on the working face based on investigation and local observation: firstly,it analyzed the mechanism that CO gas was produced by spontaneous combustion and oxygenation of gob residual coal;next,it illus- trated the theory that special coal seam deposits natural CO gas,and provided correlative experiment data;and then,it illustrated the reason of the CO gas in working face in- creased relatively in the course of coal cutter's shearing,according to the translation be- tween mechanism energy and inner energy and the rupture of carbon molecule side chain during coal exploitation;lastly,illustrated the reason of CO gas appearance and the rela- tively release quantity during coal mine blasting underground.We find out the source of CO gas on the working face accurately,and provide advantages for appropriate prevention and practical management measures.

Dependability Analysis for Fault-Tolerant Computer Systems Using Dynamic Fault Graphs

Dependability analysis is an important step in designing and analyzing safety computer systems and protection systems.Introducing multi-processor and virtual machine increases the system faults' complexity,diversity and dynamic,in particular for software-induced failures,with an impact on the overall dependability.Moreover,it is very different for safety system to operate successfully at any active phase,since there is a huge difference in failure rate between hardware-induced and softwareinduced failures.To handle these difficulties and achieve accurate dependability evaluation,consistently reflecting the construct it measures,a new formalism derived from dynamic fault graphs(DFG) is developed in this paper.DFG exploits the concept of system event as fault state sequences to represent dynamic behaviors,which allows us to execute probabilistic measures at each timestamp when change occurs.The approach automatically combines the reliability analysis with the system dynamics.In this paper,we describe how to use the proposed methodology drives to the overall system dependability analysis through the phases of modeling,structural discovery and probability analysis,which is also discussed using an example of a virtual computing system.

Distributed virtual environment-based safety control for Internet tele-robots

The inherent complexity and uncertainty of multi-operator multi-robot （MOMR） tele-operation system make its safeguard an essential problem. Hazardous factors in the system are analyzed using fault tree analysis（FTA） technology, and three-layer interactive safety architecture with information flow is designed in modules to control the factors according to the holistic control mode. After that, distributed virtual environment （DVE） including the characteristics of virtual guide （VG） technology is discussed to help the operators achieve some tasks through the visibility of control commands, time-delay, movement collision and operators＇ intentions. Finally an experiment is implemented to test the efficiency of safety control architecture by using two robots to place some building blocks in the same workspace.

Reliability Enhancement of the Diverse Protection System Regarding Common Cause Failures

The issue of CCF （common cause failure） in digital I ＆ C （instrumentation and control） systems is of great interest because an increasing number of such systems are implemented in nuclear power plants. For the mitigation of ATWS （anticipated transients without scram） as well as CCF within the PPS （plant protection system） and the ESF-CCS （engineered safety feature-component control system）, the ADPS （advanced diverse protection system） has been developed by KEPCO E ＆ C （KEPCO Engineering and Construction） Company for new nuclear units in Korea. As compared to the DPS （diverse protection system） design of APR1400, the ADPS has a diverse safety injection function considering a LBLOCA （large break loss of coolant accident） concurrent with the CCF of the PPS and ESF-CCS. Besides the function of SIAS （safety injection actuation signal） initiation, several CCF avoidance features, such as the changes of software design classification, communication methods, equipment platform, and man-machine interfaces, are introduced to enhance the reliability of the ADPS. In addition, the ADPS has recently incorporated four redundant channels with 2-out-of-4 voting logics to enhance its fault tolerant capability. Therefore, it is expected that the ADPS can provide an enhanced reliability regarding possible CCFs in the safety-grade digital I ＆ C systems as well as the ADPS itself.

A fault injection model-oriented testing strategy for component security

A fault injection model-oriented testing strategy was proposed for detecting component vulnerabilities.A fault injection model was defined,and the faults were injected into the tested component based on the fault injection model to trigger security exceptions.The testing process could be recorded by the monitoring mechanism of the strategy,and the monitoring information was written into the security log.The component vulnerabilities could be detected by the detecting algorithm through analyzing the security log.Lastly,some experiments were done in an integration testing platform to verify the applicability of the strategy.The experimental results show that the strategy is effective and operable.The detecting rate is more than 90%for vulnerability components.

Analysis of STC Fault in Urban Rail Transit Station of Mobile Block System

Mobile block system is a new type of block technology based on the theory of interval block. This article focuses on the analysis of safety key points, the efficient use of emergency time, the maximum efficiency of mobilizers, to reduce the loss of emergency incidents and casualties.

Optimization of Telephone Occlusion Method on Urban Rail Transit in Shanghai

Telephone occlusion method is a backup manual occlusion method during an urban rail transit signal equipment failure, which ensures that metro operated safely and orderly. Through the results of several telephone occlusion exercises, find out the shortcomings oftclcphone occlusion method and optimizing it.

Study on fault source diagnosis technology and air velocity trans- ducers placement for underground

The current mine safety monitoring system used can only get the air volume change of roadway placed air velocity transducers, as this change is caused by this roadway, or for other roadway, and fault source has one point or more, which be- longs to the problem of fault source diagnosis for ventilation system. Ventilation system fault can be attributed to the variation of air resistance of branch in the entire network. If the changes of air resistance for each branch in ventilation system are ana- lyzed, then it is impossible to place air velocity transducers in every branch. Therefore, the problem of the minimum quantities and location for placing air velocity transducers should be mainly studied. The relationship of air resistance and air volume variation of matrix method has been proposed, which can reflect the variation relationship between the air volume of the branch and air resistance of the relevant branches. Fault roadway range library of ventilation network built to determine fault roadway range will cause air velocity to exceed the limit. Minimum and full coverage of distribution method has been proposed, and the concept of branch coverage degree and impact roadway range library has also been brought forword to get the macro-distribution of air velocity transducers.

The Study on Wireless Mesh Networks Security based on Improved Coding Scheme

In a multi-hop wireless mesh network, wireless links are vulnerable due to severe channel fading, interference and physical damage. In this paper, we will provide a coding scheme to protect from multiple failures in wireless mesh networks to achieve high throughput where the redundancy is considered for the average number of failures. Our coding scheme is designed to protect from the average number of failures to increase the network throughput. When the number of failures is more than the average case, the destination will have to wait for more coded packets in the following time slots.

Preliminary Level 1 PSA Results for Sodium-Cooled Fast Reactor KALIMER-600 Conceptual Design

Core damage accident scenarios are identified for the metal-fueled, sodium-cooled fast reactor （SFR）, KALIMER-600, which is under development at KAERI. A level 1 probabilistic safety assessment （PSA） model is developed using the identified accident scenarios and the system fault tree models for the safety systems which are needed to mitigate the accidents. Using the preliminary level 1 PSA models, core damage frequency is estimated for the metal fueled KALIMER-600 conceptual design. Sensitivity studies for various design alternatives of safety systems are performed to find out optimal configurations in point of view of risk minimization.

铁路信号系统安全功能及安全保障措施研究

随着时代的发展,我国的经济水平得到了快速的发展进步。人们的日常生活水平越来越高,出行的频率也有了大幅度的提升,地面交通压力越来越大。近几年来,我国对于铁路建设的重视程度不断加深,铁路信号系统安全功能是确保铁路线路运行稳定的关键,本文主要采用故障分析法,针对列车冲突、列车脱轨、人员伤亡等几个重点问题进行分析研究,提出信号系统的改进完善措施,面向安全功能拓展,不断融入先进的信息技术,提高信号系统的安全性和全面性,提高铁路运行的时效性和安全性。

Fault tolerant channel-encrypting quantum dialogue against collective noise

In this paper,two fault tolerant channel-encrypting quantum dialogue(QD)protocols against collective noise are presented.One is against collective-dephasing noise,while the other is against collective-rotation noise.The decoherent-free states,each of which is composed of two physical qubits,act as traveling states combating collective noise.Einstein-Podolsky-Rosen pairs,which play the role of private quantum key,are securely shared between two participants over a collective-noise channel in advance.Through encryption and decryption with private quantum key,the initial state of each traveling two-photon logical qubit is privately shared between two participants.Due to quantum encryption sharing of the initial state of each traveling logical qubit,the issue of information leakage is overcome.The private quantum key can be repeatedly used after rotation as long as the rotation angle is properly chosen,making quantum resource economized.As a result,their information-theoretical efficiency is nearly up to 66.7%.The proposed QD protocols only need single-photon measurements rather than two-photon joint measurements for quantum measurements.Security analysis shows that an eavesdropper cannot obtain anything useful about secret messages during the dialogue process without being discovered.Furthermore,the proposed QD protocols can be implemented with current techniques in experiment.