分布式组件与Web服务集成技术研究

分布式组件技术将事务逻辑和系统服务相分离，简化了系统开发的复杂性，已经成为企业应用开发的主流技术．但缺乏Web接口和通信协议难于穿越防火墙的局限性制约了其在Internet环境下的应用。Web服务是近年来提出的一种新的面向服务的体系结构，主要用来开发基于Internet的服务。针对分布式组件技术在Internet环境下数据共享和应用集成的局限性。提出了分布式组件技术和Web服务集成的方案，并以CORBA为例说明了集成中的关键技术。     

DIVE: communication architecture and programming model

This article presents the distributed interactive virtual environment (DIVE) system, software architecture for the realization and implementation of wide-area Internet-based multi-user virtual environments. Over the years, DIVE has evolved into a generic tool that supports a wide range of applications and situations. The article focuses on the networking aspects that allow deployment of multi-user virtual environments on the Internet. Additionally, it presents the palette of programming interfaces and techniques offered by the system. This is highlighted by some example applications. Our experience has proven that DIVE's ability to mix interfaces has made it a system of choice for the implementation of distributed applications.     

InTouch基于CORBA的网络数据交换

介绍了InTouch组态软件的网络数据交换接口，并针对控制系统的网络化趋势，提出并设计实现了InTouch组态软件的CORBA网络数据交换接口，弥补了其原有接口的不足，使其更适合于设计分布式控制系统。     

An architecture for real-time multimedia communication systems

A multimedia communication system includes both the communication protocols used to transport the real-time data and the distributed computing system (DCS) within which any applications using the protocols must execute. The architecture presented attempts to integrate these communications protocols with the DCS in a smooth fashion in order to ease the writing of multimedia applications. Two issues are identified as being essential to the success of this integration: the synchronization of related real-time data streams, and the management of heterogeneous multimedia hardware. The synchronization problem is tackled by defining explicit synchronization properties at the presentation level and by providing control and synchronization operations within the DCS which operate in terms of these properties. The heterogeneity problems are addressed by separating the data transport semantics (protocols themselves) from the control semantics (protocol interfaces)     

The time-triggered architecture

The time-triggered architecture (TTA) provides a computing infrastructure for the design and implementation of dependable distributed embedded systems. A large real-time application is decomposed into nearly autonomous clusters and nodes, and a fault-tolerant global time base of known precision is generated at every node. In the TTA, this global time is used to precisely specify the interfaces among the nodes, to simplify the communication and agreement protocols, to perform prompt error detection, and to guarantee the timeliness of real-time applications. The TTA supports a two-phased design methodology, architecture design, and component design. During the architecture design phase, the interactions among the distributed components and the interfaces of the components are fully specified in the value domain and in the temporal domain. In the succeeding component implementation phase, the components are built, taking these interface specifications as constraints. This two-phased design methodology is a prerequisite for the composability of applications implemented in the TTA and for the reuse of prevalidated components within the TTA. This paper presents the architecture model of the TTA, explains the design rationale, discusses the time-triggered communication protocols TTP/C and TTP/A, and illustrates how transparent fault tolerance can be implemented in the TTA.     

SIMPPL: An Adaptable SoC Framework Using a Programmable Controller IP Interface to Facilitate Design Reuse

As the complexity of designing system-on-chips increases, so does the need to abstract low-level design issues to improve designer productivity. The reuse of previously designed Intellectual Property (IP) modules is a common form of abstraction used to reduce design time. However, different applications typically use a variety of physical interfaces, communication protocols, and global system-level control for IP modules, which complicates design reuse. In this paper, we describe the SIMPPL system model and an abstraction for IP modules, called the computing element (CE), that facilitate the SoC design for both field-programmable gate array (FPGA) and application-specific integrated circuit (ASIC) platforms. The CE abstraction decouples the datapath and system-level communication from the application-specific control to promote design reuse by localizing control redesign of IP for new applications. The SIMPPL model facilitates multi-clock domain SoC designs and expedites system integration by defining the intermodule links and communication protocols     

基于发布/订阅模型的WSN设计

为降低通信频率对节点能耗的影响同时提高大规模节点下传感器网络的连通率,本文设计了一种以发布/订阅模型作为应用层数据交互方式的无线传感器网络。该网络利用6LoWPAN技术实现组网,并以Contiki操作系统为平台完成了基于发布/订阅模型的MQTT-S应用层协议设计。测试结果表明,该设计能够有效降低节点的通信流量,实现对节点功耗以及网络通信优化,并能与互联网实现无缝连接减少开发成本,对大规模传感器网络的设计与应用具有重要意义。     

PSAR: power-source-aware routing in ZigBee networks

ZigBee is a recent wireless networking technology built on IEEE 802.15.4 standard and designed especially for low-data rate and low-duty cycle applications such as home and building automation and sensor networks. One of the primary goals of ZigBee is low power consumption and therefore long-living networks. Despite this goal, current network formation and routing protocols described in the ZigBee specification do not fully address power consumption issues. In this work, we propose a distributed routing algorithm to reduce power consumption of battery-powered devices by routing the communication through mains-powered devices whenever possible and consequently increasing the overall network lifetime. The proposed algorithm works on tree topologies supported by ZigBee and requires only minor modifications to the current specification. Our ns-2 simulation results showed that the algorithm is able to reduce the power consumption of battery-powered devices significantly with minimal communication overhead.     

An open architecture patient monitoring system using standardtechnologies

Computer-aided bedside patient monitoring is applied in areas where real-time vital function analysis takes place. Modern bedside monitoring requires not only the networking of bedside monitors with a central monitor but also other standard communication interfaces. In the paper, an approach to patient monitoring is introduced. A patient monitoring system was developed and implemented based on an existing industry standard communication network, using standard hardware components and software technologies. The open architecture system design offers scalability, standard interfaces, and flexible signal interpretation possibilities     

Reinforcement Learning for Multiple Access Control in Wireless Sensor Networks: Review, Model, and Open Issues

Wireless sensor networking is a viable communication technology among low-cost and energy-limited sensor nodes deployed in an environment. Due to high operational features, the application area of this technology is extended significantly but with some energy related challenges. One main cause of the nodes energy wasting in these networks is idle listening characterized with no communication activity. This drawback can be mitigated by the means of energy-efficient multiple access control schemes so as to minimize idle listening. In this paper, we discuss the applicability of distributed learning algorithms namely reinforcement learning towards multiple access control (MAC) in wireless sensor networks. We perform a comparative review of relevant work in the literature and then present a cooperative multi agent reinforcement learning framework for MAC design in wireless sensor networks. Accordingly, the paper concludes with some major challenges and open issues of distributed MAC design using reinforcement learning.     

CAN智能传感器设计

介绍了应用于某分布式运动控制系统和CAN智能传感器节点的软硬件设计.节点由80C196单片机最小系统、CAN通讯接口、位置检测模块等组成.节点设计方法适用于通用性的CAN总线工业测控系统.     

基于GPRS的土壤温湿度采集系统

设计了一种基于GPRS的土壤温湿度实时采集系统,给出了一种基于无线传感器网络的环境监测方案。无线传感器网络是由大量随机分布的传感器节点,通过无线通信技术自组织构成的网络,传感器节点具有数据采集处理、无线通信和自动组网能力。文中利用Telosb节点平台设计了传感器节点的硬件结构,并在TinyOS操作系统的基础上,完成了节点的软件设计。该系统可以对目标监测区内多点的温湿度进行实时采集,实现单跳和多跳的数据传输,同时利用GPRS进行高效可靠的远程传输,实现长期动态监测。     

Distributed control applications within sensor networks

Sensor networks are gaining a central role in the research community. This paper addresses some of the issues arising from the use of sensor networks in control applications. Classical control theory proves to be insufficient in modeling distributed control problems where issues of communication delay, jitter, and time synchronization between components are not negligible. After discussing our hardware and software platform and our target application, we review useful models of computation and then suggest a mixed model for design, analysis, and synthesis of control algorithms within sensor networks. We present a hierarchical model composed of continuous time-trigger components at the low level and discrete event-triggered components at the high level.     

基于IP的软件视频会议系统设计

随着网络通信和多媒体技术的发展,企业内部借助网络通信日趋频繁,基于网络的视频会议系统得到了广泛的关注。为了降低会议成本、提高会议效率,设计了一种基于IP网络的软件视频会议系统。该系统主要包括网络数据传输、音视频共享、数据交互和会议控制与管理四大功能模块,通过会议控制与管理模块控制集成以上功能模块并构成一个系统。通过该系统的实现进而改变机关事业单位内部传统的沟通方式,提高机关事业单位运作效率。     

Exploiting edge capability for wireless sensor networking

As considerable progress is being made in wireless sensor networking, it is envisioned that sensor nodes will be on the cubic millimeter scale, posing stringent constraints on the processing, communication, and storage capabilities of sensor nodes. While it is important to continue pursuing novel algorithms and protocols to squeeze the most out of the existing design space (sensor nodes), it is equally important to explore a new design paradigm for future sensor networks to reduce the complexity burden on sensor nodes. We propose to exploit capabilities at the network edge (i.e., an edge-based approach). We overview existing approaches to this end and present a novel edge-based routing protocol, called BeamStar, as a case study. We show that exploiting edge capability provides a new dimension of freedom for wireless sensor networking, and is effective in relieving the processing, communication, and storage requirements of sensor nodes.     

NERD—middleware for IoT human machine interfaces

Industrial control systems (ICS), such as smart grid systems, are frequently composed of hundreds of devices distributed over a large geographic area. While mobile applications have been used with good success in managing ICSs, traditional methods of distributing applications (e.g., app stores) are not well suited to the task of discovering, distributing, and building human machine interfaces (HMIs) for ICS, as the highly individualized and often proprietary individual components of ICSs have vastly different interfaces leading to a need to download hundreds of applications. We propose the No Effort Rapid Development (NERD) middleware framework to address the challenges of in-field HMI discovery, provisioning, communication, and co-evolution with related ICSs. Middleware services offer the ability to simplify on-demand HMI distribution and operation of ICSs. NERD leverages existing ICS device-markers (e.g., QR-codes or RFID tags) or Bluetooth low-energy protocols for rapid cyber-physical discovery and provisioning of HMIs in the field. Device-markers and Bluetooth low-energy protocols have a very limited data capacity and transmission speed, and to achieve on-device storage of HMIs, we propose using a compact data-driven domain-specific language that emphasizes data sources and sinks between the HMI and IC.     

Smart grid sensor data collection,communication, and networking: a tutorial

The smart grid is an innovative energy network that will improve the conventional electrical grid network to be more reliable, cooperative, responsive, and economical. Within the context of the new capabilities, advanced data sensing, communication, and networking technology will play a significant role in shaping the future of the smart grid. The smart grid will require a flexible and efficient framework to ensure the collection of timely and accurate information from various locations in power grid to provide continuous and reliable operation. This article presents a tutorial on the sensor data collection, communications, and networking issues for the smart grid. First, the applications of data sensing in the smart grid are reviewed. Then, the requirements for data sensing and collection, the corresponding sensors and actuators, and the communication and networking architecture are discussed. The communication technologies and the data communication network architecture and protocols for the smart grid are described. Next, different emerging techniques for data sensing, communications, and sensor data networking are reviewed. The issues related to security of data sensing and communications in the smart grid are then discussed. To this end, the standardization activities and use cases related to data sensing and communications in the smart grid are summarized. Finally, several open issues and challenges are outlined. Copyright © 2012 John Wiley & Sons, Ltd.     

相控阵雷达分布式温湿度调控系统可靠性设计

雷达长期在复杂的温湿度环境中工作,容易造成其内部的电子元器件失效而影响整个雷达的稳定运行。 针对这种状况,根据某相控阵雷达分布式温湿度调控系统的可靠性设计需求,运用可靠性理论分别对该系统在硬件和软件方面的 可靠性进行设计。其中,硬件可靠性设计主要包括滤波技术、隔离技术、屏蔽技术、接地技术等;软件可靠性主要包括恢复 技术与低功耗模式、时间冗余技术、集成电路通信、RS485 通信、FATFS文件系统等。对系统进行相关试验验证,结果表 明:系统在给定的试验环境中能够正常稳定地运转,其温度和湿度的重复性、迟滞性结果均满足相应的标准,所采集和反馈的数据与试验环境数据相符,能够满足可靠性设计要求。     

点对多点多任务无线通信

本文详细的介绍了无线通信在各种通信系统中的应用，单片机MCU与无线收发模块的硬件接口设计，点对多点无线通信协议的编写，点对多点无线通信系统打包与解包的软件设计。为无线通信系统的软硬件设计提供了可靠的解决方案。     

Medusa: a scalable MR console using USB

Magnetic resonance imaging (MRI) pulse sequence consoles typically employ closed proprietary hardware, software, and interfaces, making difficult any adaptation for innovative experimental technology. Yet MRI systems research is trending to higher channel count receivers, transmitters, gradient/shims, and unique interfaces for interventional applications. Customized console designs are now feasible for researchers with modern electronic components, but high data rates, synchronization, scalability, and cost present important challenges. Implementing large multichannel MR systems with efficiency and flexibility requires a scalable modular architecture. With Medusa, we propose an open system architecture using the universal serial bus (USB) for scalability, combined with distributed processing and buffering to address the high data rates and strict synchronization required by multichannel MRI. Medusa uses a modular design concept based on digital synthesizer, receiver, and gradient blocks, in conjunction with fast programmable logic for sampling and synchronization. Medusa is a form of synthetic instrument, being reconfigurable for a variety of medical/scientific instrumentation needs. The Medusa distributed architecture, scalability, and data bandwidth limits are presented, and its flexibility is demonstrated in a variety of novel MRI applications.