Safety and reliability in superconducting fusion magnet systems

Superconducting toroidal field coils for future commercial Tokamak reactors must operate safely and reliably for periods of up to 30 years or more with minimal interruption for maintenance. This paper represents an initial attempt to consider safety and reliability issues for superconducting fusion magnets. Goals and approaches for safety and reliability are characterized. Possible accident initiators are identified, and the effect of mechanical, thermal, and electrical factors are examined, by using some early Tokamak reactor concepts as illustrations. Principal factors in magnet instrumentation and control are identified, and the role of engineered-safety features are discussed.     

SINTEF presentation, Trondheim Safety and reliability in industrial management. IEC standards on maintainability

This article gives a brief history of how the IEC became involved with R&M standards, and discusses the development of the existing IEC 706 series of Guides on Maintainability and Maintenance Support. It also discusses the work currently in hand to update the IEC range of standards on AR&M, or Dependability, which is the official IEC terminology. This work is intended to make the whole subject more cohesive and is linked with the work of other organisations including the ISO and the European CEN and CENELEC organisations. The article explains how these groups and their standards fit together and describes the new standards which are being produced to complete the new structure.     

Use of digital simulation in reliability analysis for the design of industrial process control systems

Problems of reliability evaluation in man-machine systems in industrial process control are discussed. Opportunities for wider use of digital simulation for reliability prediction of man-machine systems in the design phase are analysed. A particular cognitive model is discussed for its imminent use in reliability studies of control room operations. Expected trends in the use of existing human reliability data bases are reviewed. Unification of control room patterns and procedures in various fields of modern industry is recognized as the main factor permitting the use of human error data stores from the nuclear industry and also for other applications. Relevant restricting conditions are next specified. Finally, the main requirements for a proposed reliability predictive, simulation-based software package for system designers are specified.     

Pattern recognition,image processing and computer vision in fifth generation computer systems

It is well-known that one of the goals of research for the last two decades or so in pattern recognition and its sub-areas, such as processing, analysis and understanding of image, speech and natural language, and computer vision techniques etc., has always been to develop fundamental techniques for flexible interactive intelligent man-machine interfaces for computers. In this paper, the author tries to argue that for the evolution of fifth generation computer systems (FGCS) as defined by Japanese scientists, some of the things required are realisation and implementation of the advances in pattern recognition and its sub-areas, not only to achieve the man-machine interface with a natural mode of communication, but also for the realisation of the basic mechanisms of inference, association and learning, which are inherent both in pattern recognition and in the core functions of FGCS. The next generation computers will be knowledge-based systems, which form a subdomain of artificial intelligence (a1) techniques, and soa1 provides the essential link between pattern recognition domains and different application systems. No attempt is made to discuss other essential conceptual building blocks, such as software engineering, computer architecture and very large scale integration technology unless these become very relevant in the discussions of concerned topics of the paper. A section on limitations of perception, learning and knowledge for computing machines is also included. This work was funded by the Knowledge-based Computer Systems Project of the Department of Electronics, Government of India.     

工业控制网络及工业自动化功能安全标准研究

2006年2月26日,由科技部、国家质检总局、国家标准委等相关部门共同组织实施的“十五“”重要技术标准研究”重大科技专项顺利通过验收。国家标准委高新技术部对此次专项中涉及高新技术领域的课题进行了验收。这些专项课题的研究,大力引导自主创新,积极探索标准研制机制的创新以及运用技术标准维护国家利益的途径,确立了我国在相关产业技术领域发展的主动权,推动了我国产业结构的优化调整,带动了企业自主创新能力的提高。现我们对由国家标准委高新技术部验收的专项中的6个专项课题,在杂志上进行专题介绍,以飨读者。     

Availability, reliability and downtime of systems with repairable components

Closed-form expressions are derived for the steady-state availability, mean rate of failure, mean duration of downtime and lower bound reliability of a general system with randomly and independently failing repairable components. Component failures are assumed to be homogeneous Poisson events in time and repair durations are assumed to be exponentially distributed. The results are expressed in terms of the mean rates of failure and mean durations of repair of the individual components. Closed-form expressions are also derived for the rates of change of the various probabilistic system performance measures with respect to the mean rate of failure and the mean duration of repair of each component. These expressions provide a convenient framework for identifying important components within the system and for decision-making aimed at upgrading the system availability or reliability, or reducing the mean duration of system downtime. Example applications to an electrical substation system demonstrate the use of the formulas developed in the paper.     

Strength and reliability of piping systems

Analytical and numerical methods have been developed for the solution of stress-strain and limit state problems of piping systems (in the case of the presence of flaws in them as well). The fracture strength of pipe steels during long-term service has been studied. A methodology and a software have been developed for the assessment of stress-strain state to extend the life of active pipelines. The developments made are used to increase the reliability of Ukrainian piping systems.     

Management policies and procedures needed for effective computer security

Although many security issues are controlled by legislative ruling and social standards, or are constrained by technological limitations, many other important matters of operational computer security are directly or indirectly under managerial control. The author argues that the necessary control policies and procedures will become increasingly critical as our reliance upon computer-based information systems continues to increase. This article presents a comprehensive framework for understanding the various aspects of computer security. Through this framework, those areas controllable by management are identified, and possible actions are proposed.     

Energy, economic, and environmental analysis of the Malaysian industrial compressed-air systems

Compressed-air systems account for about 10% of the total industrial-energy use in Malaysia and some other countries. Compressed air is typically one of the most expensive utilities in an industrial facility. Opportunities for potential savings can thus be sought and identified. This article estimates the energy used by compressed-air systems in Malaysian industries. Various energy-saving measures, such as use of high efficient motors, variable speed drive (VSD), leak prevention, use of outside intake air, reducing pressure drop, recovering waste heat, and use of efficient nozzle, were applied to save compressed-air energy and then the results were compared with available literatures. For an electric motor used in a compressed air system, a sizeable amount of electric energy and utility bill have been found to be saveable using high efficient motors and applying VSDs in matching the speed requirements. Also, significant amounts of energy and emission are reducible through various energy-saving strategies. Payback periods for different energy saving measures have been estimated and found to be economically viable in most cases.     

Theory and analysis of instrumentation systems reliability

Conclusions Expressions are given with the aid of which the following problems can be solved: the determination of reliability of instrumentation systems that permit a limited inoperative time as a result of system failure; determination of spare parts volume and the permissible inoperative time for such systems; determination of economical efficiency of such systems taking into account their reliability.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 85–88, November, 1970.     

Development of computer simulation of industrial superplastic sheet forming

A new technique estimating progressive shape changes for three-dimensional shells based on the generalized cross-sections method is introduced. The formulation of mathematical simulation of technological conditions of forming of three-dimensional shells in conditions of superplasticity is reviewed. An original algorithm of a solution finite element method with usage of orthogonal sections results. The veracity of a receivable solution is analyzed. Experimental tests are realized and a procedure to correlate the idealized forecasts with experimental data is constructed. The results and designed algorithms allow essentially to increase performance and operationability at mining new and retrofit of existing manufacturing processes of gaseous forming in conditions of superplasticity.     

Strategic defense and attack for reliability systems

This article illustrates a method by which arbitrarily complex series/parallel reliability systems can be analyzed. The method is illustrated with the series–parallel and parallel–series systems. Analytical expressions are determined for the investments and utilities of the defender and the attacker, depend on their unit costs of investment for each component, the contest intensity for each component, and their evaluations of the value of system functionality. For a series–parallel system, infinitely many components in parallel benefit the defender maximally regardless of the finite number of parallel subsystems in series. Conversely, infinitely many components in series benefit the attacker maximally regardless of the finite number of components in parallel in each subsystem. For a parallel–series system, the results are opposite. With equivalent components, equal unit costs for defender and attacker, equal intensity for all components, and equally many components in series and parallel, the defender always prefers the series–parallel system rather than the parallel–series system, and converse holds for the attacker. Hence from the defender's perspective, ceteris paribus, the series–parallel system is more reliable, and has fewer “cut sets” or failure modes.     

Computer-aided reliability analysis of fault-tolerant systems

We present an overview of the major problems inherent in reliability modelling of fault-tolerant systems. The problems faced while modelling such systems include the need to consider a very large state space, non-exponential distributions, error analysis, the need to perform a combined evaluation of performance and reliability, and the need to include the details of fault/error handling behaviour. Some of the proposed solutions are discussed and current tools (harp, save, deep andsharpe) to facilitate evaluation of such systems are described. References are provided to many of the important techniques utilized in reliability, availability, and performance modelling of such systems. This research was supported in part by the Air Force Office of Scientific Research under grant AFOSR-84-0132, by the Army Research Office under contract DAAG29-84-0045 and by the National Aeronautics and Space Administration under grant NAG1-70.     

On structural reliability of parallel systems

The distribution of strength of a bundle of perfectly brittle components in parallel with equal load sharing is studied. An early asymptotic result for stochastically independent components which is due to Daniels is generalized for components whose bearing capacities depend on a second uncertain variable in a multiplicative manner. In particular, if the componental strengths are log-normally distributed and equicorrelated it is shown that system strength is asymptotically ormal. Some applications and their validity to structural design are discussed.     

Expert systems in industrial engineering

An expert system can be denned as ‘a tool which has the capability to understand problem specific knowledge and use the domain knowledge intelligently to suggest alternate paths of action’. This paper presents a structured framework for the development of an expert system. The five major aspects of expert system development are: Problem definition; knowledge acquisition, representation and coordination; inference mechanism; implementation; and learning. These aspects are illustrated through the help pf a modular robot configuration prototype expert system. Several industrial engineering applications in the areas of process planning, facilities planning, and maintenance and fault diagnosis are discussed and a comparative analysis of the different systems is presented.