Component-based design for SCADA architecture

Supervisory control and data acquisition (SCADA) software which is suitable to distributed control systems is a demand for system developers because the characteristics of existing SCADA software packages are hard to satisfy the requirements of distributed systems. For the strengths of component-oriented techniques, this paper proposes a component-oriented architecture of SCADA software to satisfy the demand of distributed control systems. Design pattern and OPC (OLE for Process Control) technology are also used to make the openness for the architecture.     

Optimal sensor network design for multirate systems

A methodology for generating optimal sensor network design for multirate systems is presented. Location of sensors, cost of measurement and frequency of sampling are important factors that have been incorporated in the sensor network design formulation. The proposed methodology is based on evaluating trade-off (Pareto optimal) solutions between the quality of state estimation and the total measurement cost associated with the sensor network. To accommodate different sampling frequencies and evaluate their effect on state estimation accuracy, a generic multirate extension of the traditional Kalman filter is used. In general, higher accuracies of the state estimates are realizable at expense of higher measurement cost. Incorporation of these conflicting objectives of minimizing measurement cost and maximizing estimation accuracy results in a combinatorial, implicit multiobjective optimization problem, which is solved using the well-known non-dominated sorting genetic algorithm-II. The resulting solutions can be then analyzed by the process designer for determining an appropriate sensor network. The methodology is demonstrated by generating optimal sensor network design for the benchmark quadruple tank set up [K.H. Johansson, The quadruple-tank process: a multivariable laboratory process with an adjustable zero, IEEE Trans. Control Syst. Tech. 8 (3) (2000) 456–465] and the Tennessee Eastman challenge process [J.J. Downs, E.F. Vogel, A plant-wide industrial process control problem, Comput. Chem. Eng. 17 (3) (1993) 245–255].     

Integration framework for simulations and SCADA systems

Stricter requirements on the quality of industrial plant operation together with environmental limits and decreasing energy consumption bring more complex automation systems. The intelligent control techniques, which are based on approaches from diverse disciplines including statistics, artificial intelligence or signal processing, have been widely used during the last years and their benefits have been proved. They cannot be developed and tested without simulation models and access to online and historical data. This article proposes a platform for the integration of simulations and industrial SCADA systems supporting complex data access and simulation code re-use.The idea of the presented framework is to connect simulations, data sources, optimizers, other calculations and SCADA systems into one integrated environment seamlessly. A technical level of the framework provides integration of stakeholders and a semantic level captures engineering knowledge in inter-mapped ontologies and configures the technical level, which is often called model-driven configuration. The semantic level utilizes a formal model implemented as set of ontologies. The major contribution of the article are the layered model of the integration architecture and formulation of the integration requirements in the industrial automation domain. The proposed solution has been implemented and tested on a software prototype level. It is demonstrated on two use-cases covering both design and integration of simulation models from the industrial perspective. The proposed architecture is intended to be as general as possible, however it has been tested on signal-oriented simulators only. It is the main limitation of this contribution and it should be addressed in upcoming work.     

State observer design for nonlinear systems using neural network

In this paper, an observer design is proposed for nonlinear systems. The Hamilton–Jacobi–Bellman (HJB) equation based formulation has been developed. The HJB equation is formulated using a suitable non-quadratic term in the performance functional to tackle magnitude constraints on the observer gain. Utilizing Lyapunov's direct method, observer is proved to be optimal with respect to meaningful cost. In the present algorithm, neural network (NN) is used to approximate value function to find approximate solution of HJB equation using least squares method. With time-varying HJB solution, we proposed a dynamic optimal observer for the nonlinear system. Proposed algorithm has been applied on nonlinear systems with finite-time-horizon and infinite-time-horizon. Necessary theoretical and simulation results are presented to validate proposed algorithm.     

Methods for a network design problem in solar power systems

We consider the problem of minimizing cable connections between a central computer and a field of heliostats in the design of solar power systems. This practical task can be modeled as a p-median problem with additional constraints in a weighted graph. We compare an exact branch-and-bound method with two approximate algorithms. For the latter two methods, estimations of time complexity and accuracy are presented. Computational results are shown which should be useful in the design of such large-scale power systems.     

A log mining approach for process monitoring in SCADA

SCADA (supervisory control and data acquisition) systems are used for controlling and monitoring industrial processes. We propose a methodology to systematically identify potential process-related threats in SCADA. Process-related threats take place when an attacker gains user access rights and performs actions, which look legitimate, but which are intended to disrupt the SCADA process. To detect such threats, we propose a semi-automated approach of log processing. We conduct experiments on a real-life water treatment facility. A preliminary case study suggests that our approach is effective in detecting anomalous events that might alter the regular process workflow.     

A modelling and simulation based process for dependable systems design

Complex real-time system design needs to address dependability requirements, such as safety, reliability, and security. We introduce a modelling and simulation based approach which allows for the analysis and prediction of dependability constraints. Dependability can be improved by making use of fault tolerance techniques. The de-facto example, in the real-time system literature, of a pump control system in a mining environment is used to demonstrate our model-based approach. In particular, the system is modelled using the Discrete EVent system Specification (DEVS) formalism, and then extended to incorporate fault tolerance mechanisms. The modularity of the DEVS formalism facilitates this extension. The simulation demonstrates that the employed fault tolerance techniques are effective. That is, the system performs satisfactorily despite the presence of faults. This approach also makes it possible to make an informed choice between different fault tolerance techniques. Performance metrics are used to measure the reliability and safety of the system, and to evaluate the dependability achieved by the design. In our model-based development process, modelling, simulation and eventual deployment of the system are seamlessly integrated.     

A modeling tool for simulating and design of on-chip network systems

The conception of Network-on-Chip (NoC) presents system designers with a new approach to the design of on-chip inter-connection structures. However, such networks present designers with a large number of design parameters and decisions, many of which are critical to the efficient operation of over-all on-chip system. To aid the design process of complex systems-on-chip, this paper presents a NoC simulation environment that has been developed and implemented using the SystemC transaction-level modeling language. The simulation environment consists of on-chip components as well as traffic generators, which can generate various types of traffic patterns. The simulation environment has also been integrated with the NoC topology generation tool being developed in our group. A set of simulation results demonstrates the types of parameters that can affect the performance of on-chip systems, including topology variations, network latency and achievable throughput. These results also verify the modeling capabilities of the proposed simulation environment.     

电力系统传感器网低复杂度匹配滤波器设计

针对电力系统传感器网,设计了一种方波匹配滤波器,相比传统根升余弦匹配滤波器大大降低了实现复杂度。一方面方波匹配滤波器省去了传统方法中的乘法运算;另一方面,方波匹配滤波器的长度接近过采样倍数,远小于传统根升余弦匹配滤波器的长度。此外,误比特率性能仿真结果也表明了方波匹配滤波的有效性。     

基于复数域上的网络编码的MIMO系统预编码器设计*

针对复数域网络编码中复数θ的选取以及中继和目的节点处如何有效检测原始数据的问题,提出一种收发联合优化的预编码方案。首先,设计一种等相位预编码器选取编码复数θ以降低数据传输过程中的误码率,同时,提出一种迭代预均衡算法在中继和目的节点处检测和恢复原始数据,在提高系统信道容量的同时,改善整个系统的抗干扰能力。仿真结果显示,该方案相对现有复数域网络编码方案能够获得更低的误码率,且在无信道状态信息的情况下也能获得较线性预均衡方案更低的误码率以及更高的信道容量。     

Adaptive neural network control for strict-feedback nonlinear systems using backstepping design

This paper focuses on adaptive control of strict-feedback nonlinear systems using multilayer neural networks (MNNs). By introducing a modified Lyapunov function, a smooth and singularity-free adaptive controller is firstly designed for a first-order plant. Then, an extension is made to high-order nonlinear systems using neural network approximation and adaptive backstepping techniques. The developed control scheme guarantees the uniform ultimate boundedness of the closed-loop adaptive systems. In addition, the relationship between the transient performance and the design parameters is explicitly given to guide the tuning of the controller. One important feature of the proposed NN controller is the highly structural property which makes it particularly suitable for parallel processing in actual implementation. Simulation studies are included to illustrate the effectiveness of the proposed approach.     

工业生产过程中的SCADA应用分析

在分析数据采集与监视控制系统(SCADA)结构的基础上,通过文字和图表清晰的描绘出了SCADA在工业生产中的控制原理,并深入剖析了SCADA在生产过程控制中的功能与应用.     

Formalization of software design for process control systems in ferrous metallurgy

The operation of control systems in bar-rolling mills is examined and software design tools for such systems are proposed. A system of algorithmic algebras for these design tools is constructed and its capabilities are considered.Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 138–145, September–October, 1991.     

一种分布式SCADA消息中间件设计方案测控技术与仪器仪表

随着分布式SCADA系统在铁路牵引供电应用的不断推广,SCADA系统节点之间以及与其他异构系统之间进行消息数据传递面临着效率降低、接口不统一等问题。针对此问题,提出一种基于发布/订阅模式的分布式SCADA消息中间件的设计方案,该方案使用了N-Tree结构将系统消息进行逻辑区域划分,设计了一套完善的消息传递与反馈处理机制,方案中利用Quorum-Based改进型算法确保了分布式节点的消息一致性。实践及仿真实验证明,本方案提高了SCADA系统的消息传递效率,降低了分布式系统的运行负载和通信开销。     

Secure SCADA framework for the protection of energy control systems

Energy distribution systems are becoming increasingly widespread in today's society. One of the elements that are used to monitor and control these systems are SCADA (Supervisory Control and Data Acquisition) systems. In particular, these control systems and their complexities, together with the emerging use of the Internet and wireless technologies, bring new challenges that must be carefully considered. Examples of such challenges are the particular benefits of the integration of those new technologies, and also the effects they may have on the overall SCADA security. The main task of this paper is to provide a framework that shows how the integration of different state‐of‐the‐art technologies in an energy control system, such as wireless sensor networks, mobile ad hoc networks, and the Internet, can bring some interesting benefits, such as status management and anomaly prevention, while maintaining the security of the whole system. Copyright © 2010 John Wiley & Sons, Ltd.     

Physical design of the VCI wrappers for the on-chip packet-switched network named SPIN

This paper presents the physical design methodology of the VCI/SPIN wrappers. The challenge was the validation of the wrappers’ specification with Alliance CAD Tools.A wrapper is a standard gateway used by a subscriber to access an interconnect. Because there are as many wrappers as subscribers, it is relevant to have an estimation of the wrapper’s area, its frequency and then compare these results to the router’s.The interest to perform this study with academic tools is to show that commercial tools are not the unique way for experimentations.     

CNG加气母站的SCADA系统设计和研究

SCADA(Supervisory Controland Data Acquisition)数据采集和监控系统技术在工程控制领域应用广泛。结合目前天然气行业需求和技术现状,利用SCADA技术来实现CNG(Compressed naturalgas压缩天然气)加气母站自动化。系统以西门子PLC(Programmable Logic Controller可编程逻辑控制器)为基础,以现场总线和局域网为通信网络,以西门子WinCC为组态软件,结合工程实际,设计具体实施方案,实现了天然气加气母站的自动控制、远程监控和管理。提高了天然气行业的自动化水平。     

激光雷达SCADA跨平台嵌入式软件设计

为满足激光雷达系统控制与数据采集( SCADA)对跨平台的需求,利用基于组件的框架技术,在ColdFire+ μC/OSII初始平台上采用标准C语言实现了SCADA嵌入式软件.在领域分析基础上明确了SCADA软件架构,对软件架构进行可通用部分和平台依赖部分划分及组件化处理,形成SCADA软件框架,并在框架基础上完成软件设计.实验结果表明,基于框架的SCADA嵌入式软件不仅提高了软件的可靠性和可扩展性,而且实现了软件向其它平台扩展的能力,达到了设计重用和代码重用目的.     

A self-organizing neural network approach for the design of cellular manufacturing systems

The crux problem of group technology (GT) is the identification of part families requiring similar manufacturing processes and the rearrangement of machines to minimize the number of parts that visit more than one machine cell. This paper presents an improved method for part family formation, machine cell identification, bottleneck machine detection and the natural cluster generation using a self-organizing neural network. In addition, the generalization ability of the neural network makes it possible to assign the new parts to the existing machine cells without repeating the entire computational process. A computer program is developed to illustrate the effectiveness of this heuristic method by comparing it with the optimal technique for large-scale problems.     

Imperfect premise matching controller design for T-S fuzzy systems under network environments

This paper focuses on an imperfect premise matching controller design for T-S fuzzy systems under network environments. Different with the traditional parallel distribution compensation (PDC) method, the same premises between the PDC controller and the T-S fuzzy systems are no longer needed again in the proposed method. Under consideration of the unmatched grades of membership in the networked T-S fuzzy systems, a unified T-S fuzzy model is firstly proposed, in which a networked state-feedback fuzzy controller with communication delays is used to reconstruct the system. Then, based on the constructed model and by use of the Wirtinger-based inequality technique to deal with the cross items, two less conservative stability and stabilization criteria are derived to enhance the design flexibility. Finally, two numerical examples are used to show the effectiveness of proposed method.