Design and experimental research of observer-based adaptive type-2 fuzzy steering control for automated vehicles with prescribed performance

Steer-by-Wire (SbW) system is a significant electromechanical subsystem of automated vehicles. This paper proposes an observer-based type-2 fuzzy control method for the SbW system with uncertain nonlinearity, unknown modeling parameters, and unavailable state. First, an interval type-2 fuzzy logic system (IT2 FLS) and an IT2 FLS-based state observer are constructed to estimate the uncertain nonlinearity and unavailable state of SbW systems. Then, a prescribed performance control (PPC) method is proposed to achieve the prescribed tracking performance of SbW systems. Much importantly, a modified performance function is incorporated in this control method, such that the prescribed tracking performance can be guaranteed within a finite time regardless of the initial state. Finally, simulation and vehicle experiments are given to verify the effectiveness and superiority of the proposed methods.     

Computer-aided design of VLSI circuits

With the rapid evolution of integrated circuit (IC) technology to larger and more complex circuits, new approaches are needed for the design and verification of these very-large-scale integrated (VLSI) circuits. A large number of design methods are currently in use. However, the evolution of these computer aids has occurred in an ad hoc manner. In most cases, computer programs have been written to solve specific problems as they have exist and no truly integrated computer-aided desisn (CAD) systems exist for the design of IC's. A structured approach both to circuit desisn and to circuit verification, as well as the development of integrated design systems, is necessary to produce cost-effective error-free VLSI circuits. This paper presents a review of the CAD techniques which have been used in the design of IC's, as well as a number of design methods to which the application of computer aids has proven most successful. The successful application of design-aids to VLSI circuits requites an evolution from these techniques and design methods.     

Security for Industrial Communication Systems

Modern industrial communication networks are increasingly based on open protocols and platforms that are also used in the office IT and Internet environment. This reuse facilitates development and deployment of highly connected systems, but also makes the communication system vulnerable to electronic attacks. This paper gives an overview of IT security issues in industrial automation systems which are based on open communication systems. First, security objectives, electronic attack methods, and the available countermeasures for general IT systems are described. General security objectives and best practices are listed. Particularly for the TCP/IP protocol suite, a wide range of cryptography-based secure communication protocols is available. The paper describes their principles and scope of application. Next, we focus on industrial communication systems, which have a number of security-relevant characteristics distinct from the office IT systems. Confidentiality of transmitted data may not be required; however, data and user authentication, as well as access control are crucial for the mission critical and safety critical operation of the automation system. As a result, modern industrial automation systems, if they include security measures at all, emphasize various forms of access control. The paper describes the status of relevant specifications and implementations for a number of standardized automation protocols. Finally, we illustrate the application of security concepts and tools by brief case studies describing security issues in the configuration and operation of substations, plants, or for remote access.     

A computer architecture to support qualitative simulation in industrial applications

Monitoring and diagnosis of dynamic systems in industrial environments, like assembly lines and power plants, are challenging tasks. Faulty behaviors must be detected as soon as possible to avoid shutdown or damage. Recently, techniques from artificial intelligence (AI) have been applied to achieve these tasks. To overcome performance problems for the industrial application of the rather new AI technique qualitative simulation, a special-purpose computer architecture has been developed.     

Computer-aided design and performance evaluation of communicationscontrollers with mixed traffic

A design tool has been developed in the form of a computer simulation package to aid in the design and performance evaluation of communications controllers with mixed traffic. Such systems are assumed to have the capability of carrying synchronous traffic, asynchronous traffic, or the mixture of both. Multiplexing as well as switching between different types of traffic are among other features provided by these controllers. The hardware/software model is first introduced, and then the computer simulation program is presented along with some results related to the system throughput and delay. A direct application would be in a word processing environment where both inquiry/response as well as file transfer traffic exist     

Remarks on n -D Polynomial Matrix Factorization Problems

Multidimensional (n-D) polynomial matrix factorizations are intimately linked to many problems of multidimensional systems and signal processing. This paper gives a new result for a n-D polynomial matrix to have an minor prime factorization using methods from computer algebra. This result may be regarded as a generalization of a previous criterion under a special restriction [IEEE Trans. Circuits Syst. II: Exp Briefs, vol. 52, no. 9 (2005)]. Examples are given to illustrate results using computer algebra software system Singular.     

油田分支机构远程通信接入探讨

随着计算机网络技术的发展和油田信息化、数字化水平的提高,特别是中石化的ERP、OA等系统的上线运行,大量的财物、生产数据需要通过网络进行传输,中原油田基地内已经建立了完善的光纤通信专网承载着电话通信、生产信息数据、视频电视会议等业务。由于中原油田企业外部分支机构分布范围广,为了解决它们与油田在通信、网络、信息等方面的联系问题,根据各地区的基础条件情况,利用不同技术方法实现通信、网络等远程接入,提高油田企业的信息化水平。     

我国电力企业ERP系统应用难点及对策研究

电力企业的信息技术发展和应用逐渐受到了关注和重视,ERP系统是电力企业信息化建设的核心平台。我国电力企业ERP系统的实际应用还存在很多需要及时解决的难点,文中对这些应用难点和对策进行了研究。     

An Intrusion Detection System Model Based on Immune Principle and Performance Analysis

1　Introduction　 With the rapid development of Internet, network securityhas gotten the increasing focus of government, enterprise,even the individuals. But with the continuously spread ofnetwork application, attacks and destroys aiming at it in crease steadily also. Intrusion detection is a kind of networksecurity technique to detect any damage or attempt to tamperthe secrecy, integrality and usability of system. IntrusionDetection System (IDS) is an automated system for t…     

Simulating power electronic systems—A new approach

The time-varying topology created by the switch-mode operation of power semiconductor devices in energy conversion systems presents difficulties in analysis. Presently available methods for simulating the behavior of these systems include the use of the digital computer, the conventional analog computer, and the breadboard. A new philosophically distinct technique called "parity simulation" produces a topologically isomorphic transformation of the system under study; that is, it exhibits a 1:1 correspondence, or parity, with the structure of the actual network. A parity simulator utilizes terminal equivalent representations of network elements. The microcomputer based interface is highly user oriented. Nonlinear or time-varying element parameters are easily incorporated. Several simulation examples are presented.     

Comparing ladder logic diagrams and Petri nets for sequencecontroller design through a discrete manufacturing system

Design methods for sequence controllers play a very important role in advancing industrial automation. The increasing complexity and varying needs of modern discrete manufacturing systems have challenged the traditional design methods such as the use of ladder logic diagrams (LLDs) for programmable logic controllers. The methodologies based on research results in computer science have recently received growing attention by academic researchers and industrial engineers in order to design flexible, reusable, and maintainable control software. Particularly, Petri nets are emerging as a very important tool to provide an integrated solution for modeling, analysis, simulation, and control of industrial automated systems. This paper identifies certain criteria to compare LLDs and Petri nets in designing sequence controllers and responding to the changing control requirements. The comparison is performed through a practical system after introducing “real-time Petri nets” for discrete-event control purposes. The results reported in this paper will help: (a) further establish Petri net based techniques for discrete-event control of industrial automated systems; and (b) effectively convince industrial practitioners and researchers that it is worthy and timely to consider and promote the applications of Petri nets to their particular discrete-event control problems     

Techniques for fast simulation of models of highly dependablesystems

With the ever-increasing complexity and requirements of highly dependable systems, their evaluation during design and operation is becoming more crucial. Realistic models of such systems are often not amenable to analysis using conventional analytic or numerical methods. Therefore, analysts and designers turn to simulation to evaluate these models. However, accurate estimation of dependability measures of these models requires that the simulation frequently observes system failures, which are rare events in highly dependable systems. This renders ordinary Simulation impractical for evaluating such systems. To overcome this problem, simulation techniques based on importance sampling have been developed, and are very effective in certain settings. When importance sampling works well, simulation run lengths can be reduced by several orders of magnitude when estimating transient as well as steady-state dependability measures. This paper reviews some of the importance-sampling techniques that have been developed in recent years to estimate dependability measures efficiently in Markov and nonMarkov models of highly dependable systems     

The missing link-computer-supported telephony

From an engineering viewpoint, the physical realisation of a computer-supported telephony application involves connecting a computer with a telephone system by a signalling or data link which supports a protocol to carry command and status information between the two systems. In principle, any computer can support the computer supported telephony (CST) protocol, and the telephone system may be a PABX, an automatic call distributor, a key system or any other telephone switch. Existing or new systems can be linked by CST. The author discusses applications of CST the main one being telemarketing. The technology to support CST is not very advanced. At the heart of a modern telephone system is a computer. What CST does is link that embedded computer to a less specialised one. This technology is discussed by the author. The role of CST within the wide telecommunications and IT environment is also discussed     

Real-time digital simulation for systems control

This paper discusses techniques employed in the discrete modeling of physical systems for digital simulation and control applications. Traditional numerical integration techniques provide accurate means of model making but prove too slow for real-time simulation of complex systems or systems with fast response. For rapid digital simulation, a simplified discrete approximation is sought for the linear integro-differential operators of a continuous system. This discrete operator, a digitized transfer function, yields difference equations hopefully permitting real-time approximation of continuous system performance on a digital computer. Determination of the discrete operator is the essential goal of each of the simulation schemes described herein, though differing initial assumptions and approximations alter the resulting forms. After a brief review of these approaches to simulation, techniques for improved approximations for linear system transforms and for discrete parameter optimization and identification are developed. The optimum discrete transfer function which minimizes the sum of error squared between a linear continuous system output and a linear discrete system output is obtained. By adjusting gain parameters in the discrete transfer function, the simulation result is shown to be improved for various inputs and system nonlinearities. Application of standard variational methods to optimize the desired parameters leads to a two-point nonlinear boundary-value problem which is resolved via the techniques of quasilinearization and differential approximation. The procedure for application of various simulation methods is summarized, and the effectiveness of the methods is shown by the simulation of a second-order, nonlinear system for various inputs and sample intervals.     

eTOM模型在IMDS系统中的应用

随着电信行业的迅速发展，IT支撑系统逐步成为电信企业的核心竞争力，而其整体结构搭建成为重点问题和成败的关键。结合IMDS(information management and decision support system)系统的研究，对TMF提出的eTOM和NGOSS模型进行了探讨和分析，并创新提出了一种新型的电信IT支撑系统的体系结构。通过在IMDS系统中对该模型的应用，实现了电信企业信息系统的集中、共享，并对改类问题的解决提供了可以借鉴的实现方案。     

Survey of reliability and availability evaluation of complex networks using Monte Carlo techniques

Generally there are four main difficulties in evaluating complex large-scale system reliability, availability and MTBF: the system structure may be very complex; subsystems may follow various failure distributions; subsystems may conform to arbitrary failure and repair distributions for maintained systems; the failure data of subsystems are sometimes not sufficient, reliability test sample sizes tend to be small. It is difficult and often impossible to obtain s-confidence limits of them by classical statistics. Monte Carlo technique combined with Bayes method is a powerful tool to solve this kind of problems. In this survey, the typical existing Monte Carlo reliability, availability and MTBF simulation procedures, variance reduction methods, and random variate generation algorithms are analyzed and summarized. The advantages, drawbacks, accuracy and computer time of Monte Carlo simulation in evaluating reliability, availability and MTBF of a complex network are discussed. Finally, some conclusions are drawn and a general Monte Carlo reliability and MTTF assessment procedure is recommended.     

基于度量学的认证认可方法研究

IT系统在生命期中运行、应用和连接时一般要经历持续的改变。而很多变化只有在三年一度的C＆A过程中才能捕获到;这将增加系统风险的暴露。通过结构化、循序渐进的方法,提高安全度量标准,优化风险评估过程,改进认证认可方法。     

Networked intelligent robots through the Internet: issues and opportunities

Intelligent robotic systems have been extensively applied in factory automation, space exploration, intelligent buildings, surgery, military service, and also in our daily life. Various remote control methods have been performed for intelligent robotic systems, such as radio, microwave, computer networks, etc. Nowadays, the computer network services have broadly used in our daily life, such as FTP, Telnet, the World Wide Web, e-mail, etc. Consequently, it is very convenient to use the Internet to control intelligent robot, and the users will increase in the future. In the past few years, many researchers have been using the Internet as a command transmission medium which can control the intelligent robot and obtain feedback signals. Although the Internet has many advantages in a variety of fields, using the Internet to control intelligent robots also has some limitations, such as the uncertain time-delay problem, the uncertain data-loss problem, and the data-transmission security problem. In the literature, many experts proposed various methods to solve these problems. This paper will discuss these methods and analyze the effects on the remote control systems caused by these problems. The intelligent robot can simultaneously present low-level navigational capabilities, medium-level self-positioning capabilities, high-level motion-planning capabilities, and the ability to be controlled through the Internet. The issues for controlling intelligent robots through the Internet will be discussed in terms of direct control, behavior programming control, supervisory control, and learning control. Finally, we enumerate some opportunities for the application of network-based intelligent robots, and present some successful examples of networked intelligent robots in our laboratory. Future trends and concluding remarks appear at the end of this paper.     

Digital Simulation Analysis of Biophysical Systems

In the study of biophysical systems, the need for simulation often arises because a system may be better defined by assuming that the simulation model characterizes certain properties of the real system. Techniques of digital simulation and dynamic analogies, which offer much greater possibilities for quantitative analysis and synthesis of complex biological and physical systems, have become important and versatile tools. The advent and development of problem-oriented computer languages have made the simulation analysis a convenient and powerful method of problem solving and design in the diversified fields of biological engineering. Practical guides to the idealization, simplification, formulation, and analysis of biophysical systems, as well as application of computer-simulation models and routines, are discussed.     

Medical system engineering

Medical system engineering is a theoretical discipline which unifies the methods of analysis and synthesis of complex medical systems, medical technology, and public health services in general. The work of medical institutions typically involves an abundance of medical and economic information, basically in statistical form. Mathematical models of medical institutions establish regularities in the mass of empirical information and remove distortions in the statistical data, thereby aiding the work of planning organizations. Considering medical institutions as complex queueing systems involving cost estimates of the institutions themselves and implicit losses connected with delay times, gives a theoretical basis for choosing the parameters of the medical institutions to be economically optimal. To determine these parameters we must solve problems of nonlinear programming. Some particular problems of public health services are studied: i.e., determining the optimal number of beds in a hospital and the optimal number of ambulances, and determining periodicities in conducting prophylactic examinations. The study of the systems of several medical institutions and their influence on the flow of patients leads to the use of the method of statistical simulation. A simulation using the Markov process, changing the random waiting times of individual cases to their mean values, thereby decreasing the variance of the statistical estimates, is considered. A numerical example is given, illustrating one heuristic approach to estimating the accuracy of the results of this type of simulation. The contradiction between the level of scientific achievements of medicine and the possibilities of their wide practical realization is discussed in the framework of the present system of public health services where individual forms of labor prevail, hampering the effective use of medical technology. The importance of computer automation in processing medical information is pointed out.