面向有毒气体监测的无线传感器网络系统的实现

针对化工企业在生产过程中对有毒气体监测的需要,提出了一种面向有毒气体监测的无线传感器网络系统。该系统由ZigBee网络和计算机监控中心组成。ZigBee网络采用网关节点、路由器节点和传感器节点构建树状网络拓扑结构。所有节点硬件利用片上系统CC2530通信模块实现片上系统方案,节点软件利用TI公司推出的ZigBee协议栈软件Z-Stack进行开发。系统实验测试表明:基于ZigBee的无线传感器网络系统具有组网灵活,节点数量多,覆盖面广的特点,较好地解决了大区域监测环境下易于产生监测盲区的问题。     

矿井火灾环境信息动态感知与应急隔离系统

火灾区域隔离是有效控制火灾发展和蔓延的主要方法,能够切断次生事故的反应链,缩小火灾影响范围。针对常用的火灾密闭隔离措施无法对密闭环境进行实时动态监测及预报的问题,设计了矿井火灾环境信息动态感知与应急隔离系统。在预先判定的危险区域布置监测节点,通过多参数传感器和红外摄像仪对多个测点的环境信息进行同步采集并传输至地面监控平台。当监测到异常数据时,系统报警并通过远程控制方式控制密闭隔离装置开启,实现密闭囊袋充填,囊袋通过预设滑轨传动系统从存储仓扩展至整个断面,实现应急密闭隔离。通过高精度压力传感器对囊袋内部气压进行实时监测,当囊袋内部压力低于安全范围下限时,启动囊袋自动补气装置,为囊袋补充气量;当内部压力达到设定范围上限时,自动停止充气,以提升密闭效果。现场试验结果表明,该系统实现了火灾环境参数实时采集和报警、密闭隔离装置远程控制等功能,密闭囊袋可在5min内完成开启,停止充气后,囊袋内部压力基本保持稳定,满足现场应用要求。     

基于ZigBee的隧道结构安全实时监测系统设计

为避免隧道在施工过程中发生事故，针对隧道结构安全监测设计了一套完整的监测方案。该方案基于ZigBee无线通信方式，结合施工隧道特定的场景，设计了隧道结构安全监测的传感器节点、中继节点以及网关节点，并提出一种新的隧道监测数据传输策略。该系统在实验室环境下进行测试，实验结果显示，设计的监测方案各项指标能够适应在建隧道结构安全监测的需求。     

移动云环境中基于节点自适应配置的可靠服务架构

为了解决移动云计算系统中因链接断开和网络分区对服务可靠性的影响问题,提出一种基于服务副本管理和节点自适应配置的服务软件架构。其由通信中间件、监测系统、上下文管理器以及副本管理器组成。根据监测到的服务需求和节点信息,副本管理器通过一种自适应配置算法来激活或休眠节点,使任务能够在当前最适合的节点中执行,以此提高计算服务系统的可靠性。案例结果表明,该方案能够保证动态网络环境中的服务可靠性。     

基于4G无线通信技术的湿地水质COD在线监测节点设计

高效动态掌握城中湿地水体COD数据对常规地表水质监测具有重要意义。针对实验室分析COD效率低下，ZigBee网络节点通信距离有限等问题，设计了基于4G无线通信技术的湿地水质COD在线监测节点。该监测节点主控MCU选用了TI公司MSP430系列超低功耗单片机，工业级COD传感器通过隔离式RS485通信接口读取传感器数据，COD数据经4G LTE DTU模块发送至云服务器。节点采用太阳能电池板和锂电池的组合供电模式，软硬件系统采取了多种低功耗设计，保证了节点长期稳定运行。经试验分析，该监测节点运行可靠，COD数据采集精度满足要求。     

P2P系统的信任研究

由于P2P系统的开放、匿名等特点,使得P2P系统对节点缺乏约束机制,节点间缺乏信任。针对以上问题,本文提出了一种新的P2P系统信任模型,该模型根据系统中节点的历史交易情况和系统中其它节点的推荐计算节点的信任度,节点根据计算的结果决定是否进行交易。仿真试验及分析表明,该模型能有效地评估节点的信任度,隔离恶意节点,提高下载成功率。     

面向环境监测的无线传感器网络节点的软件设计

环境监测是无线传感器网络的重要应用领域。本文介绍了一种无线传感器网络节点的软件设计方案,该方案利用了基于ZigBee技术的射频芯片CC2430。节点的软件设计基于任务调度机制,用于监测某一区域内空气温湿度和土壤温湿度等环境信息。实验结果表明,节点工作状态稳定,故障率低。节点可以按照用户设置,准确地对环境信息进行采集。整个系统具备数据可靠、功耗低、可远程控制等显著优点,具有广阔的应用前景。     

温室环境无线监控系统设计

为提高温室环境监控的效率,针对传统的有线温室监控系统接线复杂和节点放置不灵活等缺点,提出一种基于无线传感器网络的温室环境监控系统的方案,并详细给出主节点和子节点的软硬件设计方案。试验结果表明,系统具有运行可靠、成本低、组网灵活以及人机交互界面友好等特点,实现了温室环境的本地监控和远程监控,能够满足当前我国温室环境监控的实际需要。     

基于车载GPS终端的城市环境健康监测平台设计

针对当前应用的空气质量监测系统定点、定时监测存在的范围局限、实时性差等问题,设计并研发了基于车载GPS终端的城市环境健康监测平台系统。系统包括车载环境感知节点、数据服务中心和PC监测终端。以STM32为主处理器的环境感知节点采集SO2、PM2.5、温湿度等空气质量信息,通过SIM5320模块获取节点的实时位置信息并与数据服务中心进行数据通信。PC监测终端可实时查看节点当前位置的空气质量状况,并绘制区域空气质量分布监测云图。系统实时准确地监测环境质量状况,弥补了当前宏观环境监测的不足,为有效控制污染及解决环境问题提供了有力参考。     

基于云平台的选煤厂环境监测系统

选煤厂环境复杂、监测面积大、监测点数量多且分散,环境参数的人工定点定时采样方式实时性差、数据准确率低,有线监测系统部署不便、成本高、线路易损坏,基于NB-IoT与LoRa技术的无线监测系统网络覆盖不足。针对上述问题,采用ZigBee无线传输技术,设计了基于云平台的选煤厂环境监测系统,介绍了系统架构、监测节点(终端节点、路由节点、网关节点)的软硬件设计及云端数据管理软件设计方案。该系统通过终端节点对选煤厂环境参数进行实时采集与处理,由路由节点汇总监测数据并转发至网关节点,网关节点对数据进行封装处理后,通过以太网上传至云平台服务器,由云端数据管理软件实现数据存储、分析与展示。测试结果表明,该系统运行稳定,数据传输准确,可实现选煤厂环境参数实时监测与告警、历史数据查询等功能。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。