Weak Serializable Concurrency Control in Distributed Real-Time Database Systems

Most of the proposed concurrency control protocols for real time database systems are based on serializability theorem. Owing to the unique characteristics of real time database applications and the importance of satisfying the timing constraints of transactions, serializability is too strong as a correctness criterion and not suitable for real time databases in most cases. On the other hand, relaxed serializability including epsilon serializability and similarity serializability can allow more real time transactions to satisfy their timing constraints, but database consistency may be sacrificed to some extent. We thus propose the use of weak serializability(WSR) that is more relaxed than conflicting serializability while database consistency is maintained. In this paper, we first formally define the new notion of correctness called weak serializability. After the necessary and sufficient conditions for weak serializability are shown, corresponding concurrency control protocol WDHP(weak serializable distributed high priority protocol) is outlined for distributed real time databases, where a new lock mode called mask lock mode is proposed for simplifying the condition of global consistency. Finally, through a series of simulation studies, it is shown that using the new concurrency control protocol the performance of distributed real time databases can be greatly improved.

Real-Time Data and Visualization Monitoring of Computer Numerical Control Machine Tools Based on Hyper Text Markup Language 5

In order to ensure the safety,quality and efficiency of computer numerical control(CNC)machine tool processing,a real-time monitoring and visible solution for CNC machine tools based on hyper text markup language(HTML)5 is proposed.The characteristics of the real-time monitoring technology of CNC machine tools under the traditional Client/Server(C/S)structure are compared and analyzed,and the technical drawbacks are proposed.Web real-time communication technology and browser drawing technology are deeply studied.A real-time monitoring and visible system for CNC machine tool data is developed based on Metro platform,combining WebSocket real-time communication technology and Canvas drawing technology.The system architecture is given,and the functions and implementation methods of the system are described in detail.The practical application results show that the WebSocket real-time communication technology can effectively reduce the bandwidth and network delay and save server resources.The numerical control machine data monitoring system can intuitively reflect the machine data,and the visible effect is good.It realizes timely monitoring of equipment alarms and prompts maintenance and management personnel.

A Model Predictive Scheduling Algorithm inReal-Time Control Systems

Abstract-The ineffective utilization of power resources has attracted much attention in current years. This paper proposes a real-time distributed load scheduling algorithm considering constraints of power supply. Firstly, an objective function is designed based on the constraint, and a base load forecasting model is established when aggregating renewable generation and non-deferrable load into a power system, which aims to transform the problem of deferrable loads scheduling into a distributed optimal control problem. Then, to optimize the objective function, a real-time scheduling algorithm is presented to solve the proposed control problem. At every time step, the purpose is to minimize the variance of differences between power supply and aggregate load, which can thus ensure the effective utilization of power resources. Finally, simulation examples are provided to illustrate the effectiveness of the proposed algorithm.

e-Automation,an Architecture for Distributed Industrial Automation Systems

Due to the complexity of modern industrial systems, a conventional automation system is not capable of providing sufficient information management and high-level intelligent approaches, as achieving these functionalities requires the support of comprehensive data management and coordination between system devices and heterogenous information. This paper proposes the concept of e-Automation, in which computer networking and distributed intelligence agent technologies are applied to industrial automation systems, and presents a hardware and software architecture that implements this concept. An open infrastructure based on multi-agent systems is employed in the proposed architecture of e-Automation, which aims to allow the implementation of diverse tasks and to permit greater configurability than can be obtained from a traditional system. To evaluate our proposed e-Automation concept, this paper presents a case study of substation information management which adopts the proposed e-Automation architecture in power system domain.

Real-Time Traffic Signal Timing for Urban Road Multi-Intersection

this paper develops a real-time traffic signal timing model which is to be integrated into a single intersection for urban road, thereby solving the problem of traffic congestion. We analyze the current situation of the traffic flow with release matrix firstly, and then put forward the basic models to minimize total delay time of vehicles at the intersection. The optimal real-time signal timing model (non-fixed cycle and non-fixed split) is built with the Webster split optimal model. At last, the simulated results, which are compared with conventional model, manifest the promising properties of proposed model.

RTEX A REAL TIME EXECUTIVE FOR DCCS

This paper presents the design idea and implementation of a real time multiprocess executivededicated to a distributed computer control system(abbreviated as DCCS),RTEX.The hostprecessor is an INTEL 8344 microcontroller proper for mini size industrial control work station.A real time executive is designed to provide a friendly environment for users to develop their ownapplied software.In consideration of reliability and ease of maintenance the executive is imple-mented by a hierarchical structure with eight layers which include user applied programs,net-work communication,real time clock manager,interprocess communication,processcoordination,process manager,memory manager,hardware.For practical purpose the networkcommunication software is implemented by four layers,namely physical,datalink,transport andapplication.The bottom two layers are designed according to the Bit Bus protocol,so that thework station is compatible with the INTEL distributed system.Three parts,the kernel,networkcommunication and facilities for system initialization and applied software development are in-cluded.

Implementation of Distributed Control System for Rice Mill Using C#

The paper presents the distributed control system for rice mill using C#language.The real-time manufacturing system can be implemented by utilizing the signal from the real time control units that is more operative than other old-fashioned control systems in the extent of modern industrial days.The software-based Distributed Control System(DCS)is novel fashionable than any other conventional control systems in the state-ofthe-art manufacturing developments.This research study emphasizes on the implementation of the DCS-based rice mill using visual C#.net.The Industrial Ethernet(IE)is realized between the top level controller for the operator and the controlled station for the remote devices.The model of client-server approach is more appropriate for the automation and manufacturing research purposes.In this study,the computer graphical simulation of the complete control development is depicted in real-time status quo by visual C#language under Visual Studio 2008 software.The parallel ports in the computers of remote terminal level and the master terminal level controllers have been interconnected with port interface coding by visual C#program.

Simple, Flexible, and Interoperable SCADA System Based on Agent Technology

SCADA (Supervisory Control and Data Acquisition) is concerned with gathering process information from industrial control processes found in utilities such as power grids, water networks, transportation, manufacturing, etc., to provide the human operators with the required real-time access to industrial processes to be monitored and controlled either locally (on-site)or remotely (i.e., through Internet). Conventional solutions such as custom SCADA packages, custom communication protocols, and centralized architectures are no longer appropriate for engineering this type of systems because of their highly distribution and their uncertain continuously changing working environments. Multi-agent systems (MAS) appeared as a new architectural style for engineering complex and highly dynamic applications such as SCADA systems. In this paper, we propose an approach for simply developing flexible and interoperable SCADA systems based on the integration of MAS and OPC process protocol. The proposed SCADA system has the following advantages: 1) simple (easier to be implemented);2) flexible (able to adapt to its environment dynamic changes);and 3) interoperable (relative to the underlying control systems, which belongs to diverse of vendors). The applicability of the proposed approach is demonstrated by a real case study example carried out in a paper mill.

合流制溢流污染的影响及其控制技术发展

合流制溢流即未经处理的雨污废水直接流入受纳水体,是造成受纳水体污染和城市内涝的主要来源。首先,对合流制溢流的污染特征及其影响因素进行了总结,简要梳理了源头控制、处理设施、调蓄设施、雨天合流雨污水处理最新技术及其控制效果,以及合流制溢流控制实时控制、监测和预测的智能控制方法。合流制溢流灰色和绿色基础设施都是必要的,随着监测、降水预报、城市水文和水力模型及实时控制技术的成熟,合流制溢流系统向实时控制和模型优化预测策略发展。

自动驾驶载货汽车速度轨迹模型预测跟踪控制方法

为避免车辆质量变化与道路坡度对自动驾驶载货汽车纵向车速控制的干扰,通过智能导航系统获取车辆速度轨迹及道路坡度信息,建立车辆纵向动力学模型和压缩天然气(CNG)发动机动力学模型,并基于模型预测控制(MPC)框架设计了一种实时的动态规划(DP)速度轨迹跟踪控制器。仿真结果表明,在新欧洲驾驶循环(NEDC)和全球统一轻型车辆测试循环(WLTC)工况下,该控制器在载货汽车质量变化和道路坡度干扰条件下能使车速保持稳定,并可在优化速度跟踪误差的同时降低发动机天然气消耗量。

空间视觉测量相机地面检测及显示系统

为了给空间视觉测量相机的研制提供测试环境,充分测试空间视觉测量相机的功能及性能,基于相机的工作特点和实际测试需求,设计了空间视觉测量相机的地面检测及显示系统。地面检测及显示系统由一台高性能计算机、一台图像接收设备、图像显示软件和通信软件组成,适用于空间视觉测量相机单机、环境试验等多种情况测试。通信软件采取分布式设计,分为1个中心服务器软件、4个客户端软件;软件采用MFC架构,多线程方式运行,软件间采取TCP/IP协议进行通信。其中中心服务器软件负责与相机之间进行通信,通信协议为RS422;4个客户端软件分别实现对相机的指令控制、遥测数据的显示及监测、自动运行及在轨更新功能验证。经过多次单机测试及超过400 h的环境试验测试,空间视觉测量相机地面检测及显示系统运行稳定,对相机的各项功能及性能均能实现测试覆盖,能够满足相机研制过程中的各项测试及试验需求,提高了相机研制的测试效率。

基于Unity3D的油田抽油机三维可视化监控系统设计

针对抽油机监测形式单一、三维可视化程度低和联动性差的缺陷,引入信息―物理实时映射思想,开发了油田抽油机三维可视化监控系统。设计了抽油机数字空间,搭建虚实交互层设计架构;搭建三维可视化系统数据组成及关系框架;结合逆运动学,构建数学模型,基于五维模型和Unity 3D平台设计抽油机三维可视化系统总体架构;以游梁式抽油机为对象进行实验验证,实现了实时动态监测、虚实混合控制、运动轨迹追踪和在线预警等服务功能。为三维可视化监控在石油机械领域的落地应用和数字孪生系统的开发提供借鉴。

HL-2A装置相衬成像系统的安全连锁与远程监控

通过在相衬成像系统光路中引入电控安全快门控制激光输出,并使用延迟电路实现了安全快门与HL-2A放电运行的同步触发,保障了诊断系统的安全运行,安全快门时间响应为26ms,其抖动误差1ms;利用四象限传感器实现了激光束斑位置的实时监测,获得了HL-2A装置垂直和水平方向的振动数据。所发展的电控快门技术和激光实时监测系统不仅能够大幅提高相衬成像系统的安全性和可靠性,对于HL-2A/2M装置诊断系统的发展和完善也具有重要意义。

Timed SEFM:面向嵌入式实时控制系统的编程模型

实时任务的功能和其完成时间共同影响嵌入式控制系统的物理行为。传统的进程/线程模型缺乏时间语义,时间属性只能用优先级间接表达,任务的实际完成时间不具有确定性。Henzinger提出的LET(Logical Execution Time)编程模型用协作式的时间触发语义明确描述时间需求,但其所基于的操作系统仍沿用进程/线程模型,仍会引入时间不确定性。结合服务体/执行流模型SEFM(Servant/Exe-Flow Model)和LET模型,定义了一种时间确定的编程模型Timed SEFM,用改进的SEFM模型描述系统的功能行为,用LET描述系统的时间行为。把智能小车控制系统的实现作为研究实例。

融合云边协同的分布式铝箔厂设备监控管理系统

为了解决传统铝箔厂设备监控与管理中的问题,提出并实现了一种融合边缘节点、分布式存储与云计算的可视化铝箔厂设备监控管理系统。该系统通过边缘节点与私有云服务协同工作的方式,提供了实时监控、信息管理与故障诊断等功能,通过分布式存储服务集群针对生产数据进行可靠存储,借助公有云进行资源共享与数据分析。系统综合提供设备与人员管理、支持三维动画、集成分布式存储、离线时序预测及数据可视化等多种服务,具有安全可靠、易扩展且功能丰富等优点。提出的设备监控管理系统已成功应用于某铝箔厂的全厂设备监控,应用结果表明,该系统能够有效地进行设备状态监测与维护。

神东矿区构建综采工作面三维透视采场技术研究

为实现工作面回采期间矿压与生产管理、保障智慧矿山建设,需要构建三维透视采场。首先,基于实用矿山压力控制理论,建立采场空间结构力学模型,训练一套采场覆岩运动参数推导、支承压力分布规律计算、矿山压力实时监测数据分析与三维采场静态应力与动态应力模拟的算法体系。其次,通过采用二维三维一体化建模的方式构建三维透明地质模型、使用三维建模工具对液压支架等设备进行精细化建模、对采场上覆岩层的运动状态进行专业化建模,体现三维透视采场基本要素的全面性。通过采用三维曲面积分法解析综采液压支架相关数据、采用多目标多因素分级方法分析钻孔应力数据、采用时序序列数据分析其他数据三种方法进行采场实时监测数据分析。最后,以布尔台煤矿42204工作面为工程背景,构建了三维透视采场基本模型。所建立的三维模型能够根据地质信息、钻孔数据、矿压显现等实际情况反映应力场变化,实现采场空间采动应力随工作面推进的展示,为采煤工作面回采期间矿压与生产管理提供技术支撑。

CTCS3-300H型列控车载设备状态在线监测与智能分析系统开发与应用

针对CTCS3-300H型列控车载设备(简称:列控车载设备)各单元运行日志数据分散存储、数据转储下载接口多、数据分析工作繁琐耗时的问题,根据列控车载设备结构特点,设计了列控车载设备状态在线监测及智能分析系统。该系统统一了列控车载设备各单元的日志数据采集与传输接口,借助既有的车地无线传输通道,设计了灵活、务实的车地数据传输方案,实现了用于列控车载设备状态在线监测的事件通告报文的实时传输,提供故障日志自动下载、手动按需下载两种日志数据无线下载方式,在满足列控车载设备状态在线监测和故障分析需要的前提下,最大限度地减少车地数据传输量。通过有效利用列控车载设备日志数据进行智能分析,能够快速、准确定位故障原因,实现故障自动报警并给出处置建议,提高了列控车载设备故障应急处置和维护效率,为动车组安全运行提供强有力的技术保障。

基于船用直流电力系统的源储协同控制仿真

针对船用直流电力系统中机组并车和离网导致的功率分配和运行稳定性问题,提出一种源储协同控制策略,通过协同机组与储能系统应对不同工况,保证电力系统在不同工况下稳定运行。基于MATLAB/Simulink软件构建数学模型,并在RT-LAB仿真平台上运行该模型,通过在线调参功能对控制策略进行多工况仿真验证。仿真结果表明,在多机组投切和多种负载变化工况下,采用该源储协同控制策略能有效提升船用直流电力系统的功率分配有效性和运行稳定性,保证电力系统在各工况下稳定运行。

化工机械设备与电气自动化控制的有机融合

随着电气自动化控制技术的不断创新和快速发展,化工机械设备与电气自动化控制的有机融合成为化工企业发展和创新的必然趋势。简介电气自动化控制的类型,对化工机械设备与电气自动化控制有机融合的特点进行分析,展示化工机械设备与电气自动化控制融合在实时监测系统、紧急停车系统和安全仪表系统的应用。应用实践表明,化工机械设备与电气自动化控制的有机融合,能够提升化工产品质量、降低生产成本,减少化工机械设备的故障发生率,保障工作人员的人身安全,提高企业的经济效益,助力企业实现高质量、高效率、高标准发展。

基于数字孪生的桥梁拆除施工安全控制技术

大型桥梁进行拆除重建过程中存在大量的安全问题,针对桥梁拆除施工安全控制问题,提出了基于数字孪生的桥梁拆除施工安全控制技术;综合应用物联网、BIM、WEBGL、5G通信、人工智能等技术,最终形成一个实时可视化的对桥梁拆除运输进行自动化控制的数字孪生系统,系统的应用验证了该技术的可行性以及实用性,保证了桥梁拆除施工的安全性,为桥梁拆除施工安全控制提供了一个新的方法。