基于消息通信的安全管理系统的设计与实现

提出了一个基于消息通信的安全管理系统的模型,并描述了一个基于该模型的安全管理系统——SMP(SecurityManagementPlatform)的组成结构及其具体实现机制。讨论了系统实现中的关键技术问题及其解决方法,其中包括系统架构、消息通信机制、系统安全机制、安全风险模型、数据一致性维护等。     

异步消息机制原理挖掘与应用范畴分析

消息机制是面向对象系统和面向对象语言的基本特性,中间件的异步消息通信方式在现今异构、分布式的网络环境中异步通信得到了广泛应用。结合 GUI 框架对异步消息通信原理做了剖析,对其核心框架回调技术做了原理挖掘并不依赖语言、框架给出了实现,最后给出了异步通信的应用范畴分析,指出即使在单宿主机内的对象间通信,采用异步消息通信可改善性能及帮助解决某些基本和特殊问题。     

ZigBee消息在应用层的安全机制研究

通过对ZigBee通信协议的网络安全结构、加密算法的分析,提出可在应用层阶段加强ZigBee消息的安全性。然后通过对SOAP消息安全架构的研究和借鉴,并结合DES加密算法的原理,针对应用层的传递消息设计出加强消息安全的架构。与ZigBee协议中的原有的加密系统相比,不仅提高了加密效率,而且加强了密钥建立与管理的安全性,进而加强了内网安全性,对ZigBee通信网络的发展有重要的现实意义。     

基于ICS的嵌入式系统应用层软件架构及其应用

针对嵌入式应用软件并行设计和调试困难这一共性问题,研发了任务间通信服务ICS(Intertask Communication and Services)消息总线平台库,并据此提出一种基于ICS工作机制的嵌入式应用层软件架构.对复杂任务中相对独立的功能模块用进程来实现,创建进程的ICS邮箱,并借助于ICS消息总线平台来实现进程间安全的数据交互和流畅的行为控制.这使得进程化的不同模块可并行研发,并通过ICS消息实现模块间的并行通信和测试.最后介绍了这种架构模式在具体研发项目的应用和效果.     

一个领域消息驱动的Takia CQRS模型设计

随着企业级应用平台开发和设计的业务需求不断增长与扩大,应用系统对数据库处理效率的依赖也日渐增强。业务系统之间复杂的桥接关系,不但使业务逻辑变得更加复杂而难于解耦,也使数据访问效率变得低下。为此,实现一个基于领域消息驱动的DDD插件Takia,在不影响目前系统架构的基础上,完全兼容DDD设计,通过CQRS查询与命令分离的消息通信机制,有效地解决系统解耦问题,为企业信息系统的DDD建模提供有力的支撑。同时,这种模型不但在数据库处理效率上进行了大力提升,而且其系统稳定性也得到大幅度的改善。     

消息交互系统领域驱动测试框架研究与应用

为解决消息交互系统测试用例编写维护复杂、效率低下的问题,基于领域驱动测试思想,针对消息交互系统的特点,提出一种通用消息交互系统领域测试模型。在此基础上设计开发了消息交互系统领域驱动测试框架,用领域语言描述测试用例,采用领域驱动设计DDD四层架构,基于领域模型,对测试用例进行组织、设计和开发,并直接驱动执行,提高了消息交互系统的测试效率。     

MPI+TBB混合并行编程模型在分子动力学中的应用

为了提高分子动力学模拟在对称多处理(SMP)集群上的计算速度,在分子动力学并行方法中引入MPI+TBB的混合并行编程模型。基于该模型,在分子动力学软件LAMMPS中设计并实现混合并行算法,在节点间采用MPI及空间分解技术实施进程级并行,节点内采用TBB及临界区技术实施线程级并行。在SMP集群中的测试表明,该方法在体系较大以及节点数较多时可以明显减少通信时间,使加速比在纯MPI模型上提高45%。结果表明,MPI+TBB混合并行编程模型可促进分子动力学并行模拟且效率明显提升。     

无人车载网络高可靠HUB的设计

为满足无人车技术的不断发展及日趋复杂的车载网络带来的高带宽和高可靠性的使用要求,设计一种车载网络集线器(HUB)。采用时间触发协议(TTP),设计时间触发以太网(TTE)加星型TTP总线的架构。TTE提高数据带宽,在物理层与驱动设备采用点对点的连接方式代替总线型通信方式,提高可靠性,解决总线型通信方式一点断开,整体通信失效的问题。针对HUB的设计做详细阐述,通过实验验证了设计的可行性和可靠性,对车载网络的优化提供了可行的解决途径。     

混合机制下的SpaceWire传输延时仿真分析

为确保SpaceWire网络中高实时性消息的确定性端到端传输延时,提出将网络消息分为时间触发消息和事件触发消息的设计方法。通过对时间触发消息发送时刻的调度以及对虫洞路由器工作时间轴的规划,实现对网络消息传输的控制,设计开发一套仿真系统;构建3类网络场景,对消息传输延时仿真结果进行分析评价,验证了该系统兼并事件触发网络与时间触发网络的特点;提出一种基于SpaceWire组路由特点的网络重构方案,仿真实验验证了该方案的可行性。     

基于消息的嵌入式系统应用框架研究

为达到可重用、可扩展、可维护等要求,应用程序框架一般要采用多种设计模式进行设计,消息是Windows平台的基本驱动模式,基于消息驱动的方式,采用MVC/P及Observer等设计模式,设计一种基于消息的应用程序框架结构,该架构不受限于具体的嵌入式系统平台,可实现模块内部的紧耦合以及模块之间的松耦合,将该框架成功应用于多种机型的战术数据系统中,验证了其正确性和适用性。     

Decentralized event-triggered control strategy in distributed networked systems with delays

Event-triggered control strategies have been recently proposed as alternatives to traditional time-triggered periodic sampling for feedback control systems. This paper studies the event-triggered control problem for distributed networked control systems (NCS). In order to reduce the network traffic and the resource of computation, we propose a new decentralized event-triggered scheme for the NCS, where a subsystem broadcast its state information to its neighbors only when the subsystem’s local state error exceeds a threshold with on-line adaption. The asymptotic stability of the resulting closed-loop system is guaranteed by the event-triggered feedback scheme. In addition, the paper gives the maximal allowable positive bounds on transmission delays for the networked control systems. Finally, the results are illustrated to be efficient by one simulated example.     

Dynamic configuration management in reliable distributed real-timeinformation systems

A new architecture for large-scale information systems is presented. The original aspects of the architecture are mainly: (1) the time-triggered, message-triggered object (TMO) structuring of the middleware and the application software of distributed real-time information systems; and (2) the dynamic configuration management subsystem (DCMS), based on the supervisor-based network surveillance (SNS) scheme. The positive impacts of this TMO structuring on maintainability and service interruption bounds are first discussed, with distributed replicated information service systems and other systems as examples. The main discussion is on the DCMS architecture. As a component of the DCMS, the network surveillance (NS) subsystem enables fast learning, by each interested fault-free node in the system, of the faults or repair completion events occurring in other parts of the system. Currently, concrete real-time NS schemes that are effective in distributed systems based on point-to-point network architectures are scarce. The SNS scheme presented in this paper is a semi-centralized real-time NS scheme which is effective in a variety of point-to-point networks. This scheme is highly scalable. An efficient implementation model for the SNS scheme is presented that can be easily adapted to various commercial operating system kernels. This paper also presents a formal analysis of the SNS scheme, on the basis of the implementation model, to obtain its strongly competitive tight bounds on the fault detection latency. Finally, some DCMS implementation issues are discussed that remain to be addressed in future research     

基于网络化的航天器智能GNC系统体系架构研究

智能化的导航制导与控制系统(GNC)是提高航天器在轨自主运行能力及其智能性的关键分系统。本文从航天器GNC系统智能化的意义、智能GNC的基本特征、智能等级划分、国内外航天器智能信息系统研究现状等方面进行了介绍,结合国内航天器GNC系统研究现状,提出了下一代基于时间触发以太网(TTE)技术的航天器智能GNC系统体系架构,指出了需要研究的主要内容及关键技术,为航天器智能GNC系统的发展提供技术参考。     

Dependable and predictable time-triggered Ethernet networks with COTS components

TTEthernet is a cross-industry communication standard that supports the integration of predictable time-triggered communication and event-triggered standard Ethernet traffic. This paper explores the ability of extending the firmware of Commercial-Off-The-Shelf (COTS) routers in order to support TTEthernet. Thereby, we can achieve a significant cost reduction, upgrade existing infrastructures and make field-failure rates of COTS devices available for certification. Based on a generic model of a COTS router, we introduce four methods for extending a COTS router with support for time-triggered and event-triggered message exchanges. The extended COTS router redirects time-triggered messages within pre-planed time intervals, while also processing event-triggered messages when no time-triggered message are scheduled. We achieve temporal predictability and low jitter by minimizing the effect of event-triggered messages onto the timing of time-triggered messages. Furthermore, experimental results from a prototype implementation provide insight into the performance differences between a COTS router and dedicated hardware.     

轨道交通乘客信息系统的设计

基于综合计算机网络技术和数字多媒体技术,提出了轨道交通乘客信息系统的一种设计方案,详细阐述了系统总体结构、主要功能和运行模式.该系统采用模块化设计,由控制中心子系统、车站子系统、网络子系统、车载子系统组成,具有正常、准实时、录播等多种运行模式,可实现运行信息播报和显示、视频资讯、告警、自诊断、图像监控等功能,并可与其他系统进行数据交换,不仅支持多任务管理,而且支持多用户管理.该系统的设计与实现可以为乘客提供直观、高效和人性化的服务,提高地铁运营管理水平,扩大地铁对乘客服务范围.     

Systematic formal verification for fault-tolerant time-triggeredalgorithms

Many critical real-time applications are implemented as time-triggered systems. We present a systematic way to derive such time-triggered implementations from algorithms specified as functional programs (in which form their correctness and fault-tolerance properties can be formally and mechanically verified with relative ease). The functional program is first transformed into an untimed synchronous system and, then, to its time-triggered implementation. The first step is specific to the algorithm concerned, but the second is generic and we prove its correctness. This proof has been formalized and mechanically checked with the PVS verification system. The approach provides a methodology that can ease the formal specification and assurance of critical fault-tolerant systems     

Mixed-triggered communication with limited elastic slot boundaries

Time-triggered systems provide dependable and deterministic communication based on strict time boundaries for tasks and messages. On the other hand, event-triggered communication is less strict on requirements and more flexible, but it is difficult to provide fault isolation. Thus, the combination of time-triggered and event-triggered communication is desirably extending a time-triggered communication system by a dynamic property. This paper improves a novel mixed-triggered communication approach based on ESBs which adds limited delay tolerance to an otherwise strict real-time communication. The presented approach overcomes the problem of delayed respectively missing messages by adding fail-operational behavior to the ESB-based communication. This is achieved by extending the basic mechanism using additional fault-tolerant features. The presented mechanism allows the system to stay operable even when messages occasionally violate their planned slot boundaries and provides fault isolation for timing violations beyond a predefined tolerance budget. The introduced fault-tolerant features are analyzed via Monte-Carlo simulations where the resulting data throughput is compared to two straightforward hard real-time communication approaches. As our results show, the proposed guards enable the system to handle extended message reception delays while, compared to strictly bounded communication, having a better performance of successfully transmitted messages.     

事件触发双模分布式预测控制

本文针对有界扰动作用下的线性离散大系统,提出了事件触发双模分布式预测控制设计方法.利用输入状态稳定性(input-to-state stability,ISS)理论建立了仅与子系统自身信息相关的事件触发条件.只有子系统满足相应的事件触发条件,才进行状态信息的传输和分布式预测控制优化问题的求解,并与邻域子系统交互最优解作用下的关联信息.当子系统进入不变集时,采用状态反馈控制律进行镇定,并与进入不变集的邻域子系统不再交互信息.分析了算法的递推可行性和系统的闭环稳定性,给出了扰动的上界.最后,通过车辆控制系统对算法进行仿真验证,结果表明,本文提出的方法能够有效降低优化问题的求解次数和关联信息的交互次数,节约计算资源和通信资源.     

Decentralized adaptive control of nonlinear systems using radialbasis neural networks

Stable direct and indirect decentralized adaptive radial basis neural network controllers are presented for a class of interconnected nonlinear systems. The feedback and adaptation mechanisms for each subsystem depend only upon local measurements to provide asymptotic tracking of a reference trajectory. Due to the functional approximation capabilities of radial basis neural networks, the dynamics for each subsystem are not required to be linear in a set of unknown coefficients as is typically required in decentralized adaptive schemes. In addition, each subsystem is able to adaptively compensate for disturbances and interconnections with unknown bounds     

基于AVR的时间触发嵌入式系统

介绍一种基于AVR单片机的时间触发嵌入式系统,重点描述了该操作系统的结构.系统具有所占存储单元少,可靠性好,安全性高的特点.可以预测,这种基于单片机AVR的时间触发嵌入式系统有很好的应用市场前景.