Memory as a network abstraction

An approach to interprocesses communication over fast networks is described. It is based on the assumption that the essence of the problem was the network abstraction, that is, what model the hardware network interfaces provides to the computer. In this approach the network provides the abstraction of computer memory, directly to the application, with no operation system intervention required to effect the movement of data. Three systems based on this idea are examined. They are Memnet, Mether, and CapNet. UPWARDS, an attempt to develop software that can provide access to the bandwidth available in the future high-speed WANs, is also discussed     

基于IEEE标准的智能监测系统集成研究

文中针对综合监测系统传感器之间接口兼容及网络互操作性问题,基于IEEE1451智能传感器接口和CAN总线技术,对一款开放式、“即插即用”的智能监测系统集成研究。结合IEEE1451．2和IEEE1451．4接口标准,完成执行器模块（STIM）、TII接口电路及传感器电子数据表单（TEDS）方案的设计;基于CAN总线技术完成网络适配器（NCAP）硬件模块、容错协议和优先晋升算法的设计。节点通信实验分析表明,系统可靠性高,实时性良好。     

A service-centric model for wireless sensor networks

Most of the current research in wireless sensor networks (WSNs) is constraint driven and focuses on optimizing the use of limited resources (e.g., power) at each sensor. While such constraints are important, there is a energy for more general performance metrics to assess the effectiveness of WSNs. There is also a need for a unified formal model that would enable comparison of different types of WSNs and provide a framework for WSN operations. We propose a new service-centric model that focuses on services provided by a WSN and views a WSN as a service provider. A WSN is modeled at different levels of abstraction. For each level, a set of services and a set of metrics are defined. Services and their interfaces are defined in a formal way to facilitate automatic composition of services, and enable interoperability and multitasking of WSNs at the different levels. A two-way mapping between two neighboring levels is then defined as a decomposition (from higher to lower level) and composition (from lower to higher level). A composite mapping between metrics at different levels connects high-level, mission-oriented metrics and low-level, capability-oriented metrics. The service-centric model consists of mission, network, region, sensor, and capability layers. Each layer has associated semantics that use lower level components as syntactic units (except for the capability layer). Within each layer there are four planes or functionality sets; communication, management, application, and generational learning. The combination of layers and planes enables a service-based visualization paradigm that can provide better understanding of the WSN. The service-centric model provides a holistic approach to measuring and presenting WSNs effectiveness. In addition, it presents a general and flexible framework in which various more specific WSN models can be represented and evaluated.     

嵌入式系统网卡驱动模型设计与实现

以嵌入式系统下网卡驱动的功能为出发点,提出了一种嵌入式系统下网卡驱动设计模型,通过在网络协议层与网卡驱动之间增加一个网卡驱动功能抽象中间层,有效地隔离上层网络协议与底层具体的网卡驱动,使得驱动实现的细节对上层协议透明。中间层作为网卡驱动的抽象层,在提供网卡驱动控制服务的同时,可实现网络层协议与驱动之间的交互;有效地简化网卡驱动的设计工作。通过在合适的平台上进行验证和测试,实验结果证明该模型能有效指导嵌入式系统网卡驱动的设计,网卡驱动能正确,可靠地工作,网络通信功能正常。     

基于异步传输的IPSEC安全加密芯片应用

目前配电终端安全加密芯片与MCU之间主要采用SPI总线进行同步通信,由MCU输出网口数据实现配电终端应用层安全加密通信。为进一步提高安全加密防护能力,本文选用IPSEC安全加密芯片直接输出网口数据,芯片与MCU之间采用异步数据传输,实现网络层安全加密防护功能。在此基础上研究了基于安全加密芯片的配电网络双层加密防护应用,通过对内嵌安全加密芯片的终端进行软硬件设计,并研究配电终端与主站之间的加密应用,提升了配电终端加密通信的安全性与可靠性。通过IPSEC极限通信测试、应用加密测试以及现场实际测试,验证了内嵌安全加密芯片的配电终端的加密防护性能。     

IEEE Standard 1451 and a proposed time synchronization approach

This paper proposes enhancements for the IEEE 1451 set of standards for smart transducers. The implementation in a distributed network of the IEEE 1588 protocol to synchronize the real-time clocks included in the IEEE 1451 devices (TIMs and NCAP) that constitute the network is described in this paper, and the results obtained are presented. The measuring system uses the USB ports of the PC, which emulate the NCAP, to connect two TIMs, and the implementation in the distributed system of the IEEE 1588 protocol to synchronize the real-time clocks present in the TIMs allows trigger synchronization accuracies of several hundreds of nanoseconds.     

RTIDDS在业务管理与资源优化系统中的拓展应用

RTI DDS是位于网络协议栈最上层的软件,它屏蔽底层网络代码,代之以通用的、基于标准的应用程序接口(API),规定了实时分布式系统中数据发布、传递和接收的接口和行为,通过API提供易于理解的基于发布/订阅的通讯模式。业务管理与资源优化是战术网络中用于对网络业务管理和网络资源优化的本地服务软件,利用DDS的总线服务功能,能够快速有效地将业务管理与资源优化前端同步拓展到多个使用平台上。     

基于国产密码算法的数控网络的认证与验证模型研究及安全评估

该文针对工业控制系统安全,提出面向数控系统(NCS)网络安全保护技术框架,选用国产密码系列算法中的SM2, SM3, SM4算法,设计并建立了数控网络(CNC)认证与验证模型(AUTH-VRF),分内外两层为数控网络提供安全防护。外层为数控网络设备间通信与传输进行安全认证实现网段隔离,内层验证通信协议完整性以确保现场设备接收运行程序的正确性与有效性;通过基于SM2, SM3, SM4算法设计和部署的外层防护装置,为分布式数控(DNC)设备与数控系统之间的通信提供身份认证与文件加密传输;同时针对工业控制网络的S7Comm工业通信协议数据,通过SM3算法验证专有工业协议数据完整性。通过网络攻击实验证明,AUTH-VRF模型可以为数控网络中工业生产数据提供有效的安全认证和资源完整性保护,为满足我国关键基础设施“国内、国外工业控制系统产品共同安全可控”和“安全技术深入工业控制系统各个层级”的需求提供了实际可行的技术参考方案。     

An all-IP software radio architecture under RTLinux

This paper presents an overview of software radio architectures for testing quality-of-service (QoS) aware IP data services over a typical third-generation radio interface. The testbed is implemented using a hard real-time micro-kernel known as RTLinux, running beneath the Linux operating system, for providing real-time end-to-end functionality. The testbed runs on a variety of Intel Pentium-based computing platforms including laptops and high-end servers. Layers 1 and 2 are compliant with the 3GPP specifications forTdd operation and layer 3 provides a direct interconnection with an IPv6 core network. The intent is to study the impact of an ip core network and QoS constraints on the physical and link layers as well as the co-design of physical layer configurations and IP layer networking.     

A software architecture for workstations supporting multimediaconferencing in packet switching networks

The software architecture of a multimedia workstation connected to an experimental packet switching network which is capable of switching voice, data, and video simultaneously is described. The user of a multimedia workstation may engage in several multimedia calls, each using multiple information streams consisting of voice, data, and images. The network interface software in the workstation maintains the temporal relationship among a given call's information streams. For each call, the network interface provides a multiple information channel interface to upper layer software supporting the notion of a multimedia virtual circuit. A connector mechanism is provided to control the information exchange among the network interface, the various voice, data, and image peripherals, and the computer programs used in a multimedia application. These information sources and sinks share a common abstraction called active devices     

基于软交换的个人监控通信

网络的融合及终端智能化程度的提高，为个人监控通信的实现提供了条件。借助于M2M技术，软交换网络可以为个人监控通信提供理想的实现平台。基于软交换的网络架构和实现原理，个人监控通信系统可分为网络侧和用户侧两部分。网络侧设备包括软交换机、现场业务中心等，位于核心控制层和业务层；用户侧设备包括监控设备、现场设备、网关和现场控制平台，位于接入层和现场设备层。通过基于软交换的个人监控通信系统可以实现家庭自动化、公共服务、资源调度、安全监测以及社群互助等多种人机通信业务。随着机器智能的提高和网络的融合，将来个人监控还会不断完善和发展，极有可能成为未来通信的主流业务之一。     

Implementation of an SDR platform using GPU and its application to a 2?��?2 MIMO WiMAX system

Conventional communication systems have been implemented using digital signal processors (DSPs) and/or field programmable gate arrays (FPGAs), especially for software defined radio (SDR) functionality. We propose a scheme that uses a graphics processing unit (GPU) in place of the conventional DSPs or FPGAs for the implementation of an SDR-based communication system. The GPU, a high-speed parallel processor with multiple arithmetic logic units, is adopted for the signal processing of the physical layer required for the parallel processing in an SDR system. The compute unified device architecture (CUDA) based on the C language provides a software development kit (SDK) for the modem application of the GPU. Therefore we utilize the CUDA SDK to implement the real-time modem function. This paper presents an implementation of a 2 × 2 multiple-input multiple-output (MIMO) WiMAX system employing a GPU as the real-time modem. By installing a radio frequency module on top of the GPU modem, we implement a real-time transmission system for video data. The performance of the proposed GPU-based system is demonstrated by comparing its operation time against that of the conventional DSP-based system.     

An icon-based approach to system control development

The implementation of an icon-based manufacturing message specification (MMS) messaging system for system control in a manufacturing automation protocol (MAP environment) is described. The system was designed with a four-layer hierarchy. The top layer acts as a user interface and essentially provides a data manipulation service. The next layer invokes the appropriate firmware calls to manage the communication process. The third layer consists of the firmware that handles the actual transmission of data across the network. The lowest level is the actual network hardware. Twelve MMS services were implemented in order to provide the capability to carry out a typical control session. The system was tested using software that simulates the external communications of an MMS virtual manufacturing device. The LabVIEW MAP environment used imposed at least two limitations on the operation of the system. First, LabVIEW makes no provision for data structures; therefore, each parameter had to be passed from the MMS layer to the code VI layer as a variable of a specific data type. Second, LabVIEW provides no convenient way to maintain global variables throughout a diagram     

Matisse: A System-on-Chip Design Methodology Emphasizing Dynamic Memory Management

MATISSE is a design environment intended for developing systems characterized by a tight interaction between control and data-flow behavior, intensive data storage and transfer, and stringent real-time requirements. Matisse bridges the gap from a system specification, using a concurrent object-oriented language, to an optimized embedded single-chip hardware/software implementation. Matisse supports stepwise exploration and refinement of dynamic memory management, memory architecture exploration, and gradual incorporation of timing constraints before going to traditional tools for hardware synthesis, software compilation, and inter-processor communication synthesis. With this approach, specifications of embedded systems can be written in a high-level programming language using data abstraction. Application of MATISSE on telecom protocol processing systems in the ATM area shows significant improvements in area usage and power consumption.     

The Grid Application Toolkit: Toward Generic and Easy Application Programming Interfaces for the Grid

Core Grid technologies are rapidly maturing, but there remains a shortage of real Grid applications. One important reason is the lack of a simple and high-level application programming toolkit, bridging the gap between existing Grid middleware and application-level needs. The Grid Application Toolkit (GAT), as currently developed by the EC-funded project GridLab, provides this missing functionality. As seen from the application, the GAT provides a unified simple programming interface to the Grid infrastructure, tailored to the needs of Grid application programmers and users. A uniform programming interface will be needed for application developers to create a new generation of "Grid-aware" applications. The GAT implementation handles both the complexity and the variety of existing Grid middleware services via so-called adaptors. Complementing existing Grid middleware, GridLab also provides high-level services to implement the GAT functionality. We present the GridLab software architecture, consisting of the GAT, environment-specific adaptors, and GridLab services. We elaborate the concepts underlying the GAT and outline the corresponding application programming interface. We present the functionality of GridLab's high-level services and demonstrate how a dynamic Grid application can easily benefit from the GAT. All GridLab software is open source and can be downloaded from the project Web site.     

A Statistical Method for Reconfiguration of Cognitive Radios

Recent developments in computer technology have enabled radio developers to accomplish in software what traditionally was performed with application-specific integrated circuits. A radio that has the core of its functionality implemented in software is called a software-defined radio. When an SDR has the capability to sense, reason, and dynamically adapt to requirements and environmental change, we call this more capable device a cognitive radio. Many private and public agencies are investing in the promise of CR to improve the utilization of radio frequency spectrum. They envision devices that can sense frequency vacancies and dynamically reconfigure to utilize idle channels. The promise of CR depends on the capability of a radio to change operating frequencies, power, and/or modulation schemes (physical layer flexibility). In addition to this physical layer flexibility, there are a large number of opportunities to capitalize on the interplay of the CR physical layer configuration and other parameters in the radio network protocol stack. At the core of CR functionality is the ability to select from thousands of potential configurations to maximize performance-be it in terms of spectrum use, throughput, or reliability. In this article, we describe a method for selecting from a number of potential configurations to fulfill the communication requirements of a CR network. By using accepted statistical methods, we show how parameters at the physical, data link, network, and application layers interact to affect performance. We build upon this parametric insight with our presentation of a technique for predicting radio performance.     

Packet Switching in the MICRONET Network Computer

Packet switching is a communication technology which has been used extensively in geographically distributed computer networks. It is also applicable to the communication subnetworks of compact multimicrocomputers known as network computers. This paper describes the use of the language Concurrent Pascal to build a packet-switching subsystem for the MICRONET network of DEC LSI-11 microcomputers. Examples of actual Concurrent Pascal source code taken from the system demonstrate the usefulness of high-level languages with abstract data types for complex communication software.     

Timing Synchronization in MF-TDMA Systems for Geostationary Satellites[Topics in Radio Communications]

The most expensive costs in satellite communication are incurred by the space segment. Therefore, effort should be focused on the efficient use of this resource. One aspect is the optimization of the physical layer, to approach the Shannon limit of channel capacity. In IP-based networks, communication between arbitrary terminals can be established, which must hold for IP-based satellite networks as well. A commonly used topology is the star network, where data are routed via the master station, which in case of satellite communications introduces a double hop for terminal-to-terminal connections [1]. A double hop requires twice the bandwidth and twice the response time, which is very unattractive for interactive services. This drawback is avoided with a fully meshed topology, where terminals can communicate directly. Of course, an appropriately designed access system is required in this context. The well-known multi-frequency, time-division multiple access (MF-TDMA) scheme slices the channel capacity along both time and frequency axes. Each fragment (slot) can be used by any station for direct communication [2, 3]. This article describes the method on an abstraction layer, starting with the high-level timing that copes with frame numbers; the low-level timing that maps the frame numbers to time instants of the local time scale; and ends with the time stamp handled in the hardware, where calculation delays and filter flushing affect the received time stamp. Compared to commercial systems, the method described in this article uses differential time stamps, which reduces the effort of the synchronization procedure.     

基于5G的警务集群系统

通过分析集群通信系统沿专网与公网方向发展演进的技术趋势,结合公安调度需求研究了基于5G切片的警务集群系统体系结构,包括应用层、服务层、传输层、终端层、标准及管理体系和安全保障体系。在网络组网架构方面,通过超高可靠低时延通信(Ultra-reliable and Low Latency Communications,uRLLC)切片传输控制信号,增强型移动宽带(Enhanced Mobile Broadband,eMBB)切片传输业务内容,并提出集群业务软件中通信调度业务逻辑、综合业务适配和维护管理软件的模块组成,对其应用的协同算法、时延保证、安全可靠性和可扩展性等关键技术问题给出建议。基于多智能体控制模型提出多接入边缘计算(Multiple Access Edge Computing,MEC)服务器之间状态同步协调算法,为警务集群系统在5G技术体制下的进一步发展提供了基础。     

面向CAN总线健壮性的形式化建模与验证

为评估控制器局域网络（Controller Area Network,CAN）攻击者入侵风险的影响,增强CAN总线设计的健壮性,提出了一种基于UPPAAL SMC的CAN总线健壮性验证方案。该方案首先针对嵌入式软件系统需求对CAN总线数据链路层与应用层进行形式化建模,采用模型检测技术对总线控制、收发、仲裁、应用层等功能进行仿真;其次使用攻击报文对CAN总线系统抗攻击性能进行验证与分析,开发人员可根据验证结果改进软件需求参数指标。实验结果表明,参数优化后,在总线被攻击情况下节点传输的准确率保持在75%以上,应答正确率可提升12.4%,加强了总线抗攻击能力。该方法为嵌入式软件通信总线系统设计的合理性提供了理论指导,规避开发后期的风险,可广泛应用于通信总线安全性能验证领域。