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ESREL 2007
ARTICLE IN PRESS Reliability Engineering and System Safety 94 (2009) 1369–1370
Contents lists available at ScienceDirect
Reliability Engineering and System Safety journal homepage: www.elsevier.com/locate/ress
Editorial
ESREL 2007
This special issue is devoted to papers from the 18th European Safety and Reliability Conference, ESREL 2007, held in Stavanger Norway, June 25–27, 2007. The papers are extended and improved versions of selected presentations at the conference. All the papers have been individually reviewed and revised for this special issue of the journal. ESREL is an annual conference series promoted by the European Safety and Reliability Association (ESRA). The conference dates back to 1989, but was not referred to as an ESREL conference before 1992. The Conference has become well established in the international community, attracting a good mix of academics and industry participants that present and discuss subjects of interest and applications across various industries. Approximately 350 papers were presented at ESREL 2007. The theme of the Conference was ‘‘Safety, Reliability and Societal Safety’’. The Conference covered a number of topics within safety, risk and reliability, including risk and reliability analysis methods, maintenance optimisation, and risk management. Special focus was placed on societal safety issues, such as vulnerability analysis of critical infrastructures, risk perception, communication and governance. The application areas ranged from oil and gas, nuclear engineering and civil engineering to information technology and communication, security, transportation, health and medicine. It has been an aim of the sample of the papers included in this issue to reflect the large spectre of works presented at the Conference. However, not all topics could be covered. The selection has a focus on reliability and risk analysis methods, but also other topics are covered, for example accident investigation and decision analysis. The papers include both theoretical analysis and modelling, and more practical-oriented work. The issue comprises 13 papers. The first is by Hurdle, Bartlett and Andrews, who address fault detection and identification. The paper expands the capability of previous approaches in this area using fault trees for application to dynamically changing systems. The potential for the method to deal with additional system complexity and redundancy is illustrated by using a section from an aircraft fuel system. Distefano and Puliafito explain in their paper how dynamic reliability block diagrams can be used for reliability and availability analysis of dependent dynamic systems. The approach is compared with other methodologies. Fovino, Masera and De Cian present a new method for quantitative security risk assessment of complex systems, combining fault tree analysis, with the recently introduced attack tree analysis, proposed for the study of malicious attack patterns. The combined use of fault trees and attack trees helps the analyst to 0951-8320/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ress.2009.01.011
effectively face the security challenges posed by the introduction of modern ICT technologies in the control systems of critical infrastructures. Baiardi, Telmon and Sgandurrai’s work is also related to critical infrastructures. A main issue is the very large number of infrastructure components and the interdependencies among both these components and those of distinct critical infrastructures. The authors discuss the application of a hierarchical approach to models based upon the notion of security dependency among components in the case of attacks implemented by intelligent, i.e. goal oriented, threats to achieve one of a predefined set of goals. Kaegi, Mock and Kro¨ger look at the task of integrating maintenance work into reliability analysis. This is a difficult problem as common modelling techniques are often not applicable due to state-explosion, which calls for restrictive model assumptions and oversimplification. The authors argue that agent-based modelling of technical and organizational systems is a promising approach to overcome such problems. In this work the authors study this modelling and compare it with a Markov approach. Flammini, Marrone, Mazzocca and Vittorini study safetycritical control systems. They present a failure model for voting architectures based on Bayesian Networks and a maintenance model based on continuous time Markov chains, and they propose to combine them according to a compositional multi-formalism modelling approach in order to analyze the impact of imperfect maintenance on the system safety. Ale et al. present the structure and backbone of a causal model of air traffic safety. The backbone consists of a string of 36 separate accident categories with repetitions in each flight phase, which are based on a study of accidents and incidents over two decades. The probabilities of the various accident pathways are first quantified using fault-trees developed from accidents and incident reports. A model for the error probability of crew members has been developed and quantified using expert judgement elicitation techniques. The model is integrated in a single integrated Bayesian Belief Net, which allows consistent handling of probabilities and their interdependence. The paper by Antonioni, Bonvicini, Spadoni and Cozzani addresses tools needed to build up a general framework allowing the extension of quantitative risk assessment procedure to include the analysis of the industrial accidents caused by natural events. Specific methods and models are developed to allow the quantitative assessment of risk caused by two categories of ‘‘Na-Tech’’ accidents: accidents triggered by earthquakes and
ARTICLE IN PRESS 1370
Editorial / Reliability Engineering and System Safety 94 (2009) 1369–1370
accidents triggered by floods. The approach allows the calculation of the overall individual and societal risk indices including the multiple-failure scenarios caused by the impact of natural events. Dome´nech, Escriche and Martorell address food safety. The paper describes a methodology for measuring the effectiveness of a Critical Control Point (CCP) in terms of the risk to consumer health as well as the potential impact of company revenues. The method gives the decision-maker a quantitative tool for setting critical limits and monitoring variations at a CCP. This would allow risk management decisions to be made at-line (i.e., real time) during a specific process. Ha¨ring, Scho¨nherr and Richter study quantitative hazard and risk analysis for fragments of high-explosive shells in air. The analysis covers scenario analysis, probabilistic analysis, physical consequence analysis and damage analysis. Vulnerability models determine the individual local risk. Risk criteria are used for making judgements about the risk. Stoop and Roed-Larsen give a historical overview of developments in accident investigations in the transport industry. In particular differences among human operator models, the allocation of responsibilities across stakeholders, their power relations and tools are elaborated. The need and opportunities for a transition from accident prevention towards systems change are indicated. Kuniewski, van der Weideand van Noortwijk present a sampling-inspection strategy for the evaluation of time-depen-
dent reliability of deteriorating systems, where the deterioration is assumed to initiate at random times and at random locations. Aven and Flage consider decision problems related to production assurance and safety. The issue is to what extent we should use decision criteria based on expected values, such as the expected net present value and the expected cost per expected number of saved lives to guide the decision. Such criteria are recognised as practical tools for supporting decision-making under uncertainty, but the question is to what extent uncertainty is adequately taken into account by these criteria. Finally, we would like to thank all contributing authors for their papers, as well as all the reviewers who have helped the authors to improve the papers. We hope that the issue provides an interesting and a useful insight into important topics within reliability engineering and system safety. Terje Aven, Jan Erik Vinnem University of Stavanger, Norway Carlos Guedes Soares Technical University of Lisbon, Instituto Superior Tecnico, Lisboa, Portugal E-mail address: [email protected] Available online 10 February 2009
Corresponding author.
Contents lists available at ScienceDirect
Reliability Engineering and System Safety journal homepage: www.elsevier.com/locate/ress
Editorial
ESREL 2007
This special issue is devoted to papers from the 18th European Safety and Reliability Conference, ESREL 2007, held in Stavanger Norway, June 25–27, 2007. The papers are extended and improved versions of selected presentations at the conference. All the papers have been individually reviewed and revised for this special issue of the journal. ESREL is an annual conference series promoted by the European Safety and Reliability Association (ESRA). The conference dates back to 1989, but was not referred to as an ESREL conference before 1992. The Conference has become well established in the international community, attracting a good mix of academics and industry participants that present and discuss subjects of interest and applications across various industries. Approximately 350 papers were presented at ESREL 2007. The theme of the Conference was ‘‘Safety, Reliability and Societal Safety’’. The Conference covered a number of topics within safety, risk and reliability, including risk and reliability analysis methods, maintenance optimisation, and risk management. Special focus was placed on societal safety issues, such as vulnerability analysis of critical infrastructures, risk perception, communication and governance. The application areas ranged from oil and gas, nuclear engineering and civil engineering to information technology and communication, security, transportation, health and medicine. It has been an aim of the sample of the papers included in this issue to reflect the large spectre of works presented at the Conference. However, not all topics could be covered. The selection has a focus on reliability and risk analysis methods, but also other topics are covered, for example accident investigation and decision analysis. The papers include both theoretical analysis and modelling, and more practical-oriented work. The issue comprises 13 papers. The first is by Hurdle, Bartlett and Andrews, who address fault detection and identification. The paper expands the capability of previous approaches in this area using fault trees for application to dynamically changing systems. The potential for the method to deal with additional system complexity and redundancy is illustrated by using a section from an aircraft fuel system. Distefano and Puliafito explain in their paper how dynamic reliability block diagrams can be used for reliability and availability analysis of dependent dynamic systems. The approach is compared with other methodologies. Fovino, Masera and De Cian present a new method for quantitative security risk assessment of complex systems, combining fault tree analysis, with the recently introduced attack tree analysis, proposed for the study of malicious attack patterns. The combined use of fault trees and attack trees helps the analyst to 0951-8320/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ress.2009.01.011
effectively face the security challenges posed by the introduction of modern ICT technologies in the control systems of critical infrastructures. Baiardi, Telmon and Sgandurrai’s work is also related to critical infrastructures. A main issue is the very large number of infrastructure components and the interdependencies among both these components and those of distinct critical infrastructures. The authors discuss the application of a hierarchical approach to models based upon the notion of security dependency among components in the case of attacks implemented by intelligent, i.e. goal oriented, threats to achieve one of a predefined set of goals. Kaegi, Mock and Kro¨ger look at the task of integrating maintenance work into reliability analysis. This is a difficult problem as common modelling techniques are often not applicable due to state-explosion, which calls for restrictive model assumptions and oversimplification. The authors argue that agent-based modelling of technical and organizational systems is a promising approach to overcome such problems. In this work the authors study this modelling and compare it with a Markov approach. Flammini, Marrone, Mazzocca and Vittorini study safetycritical control systems. They present a failure model for voting architectures based on Bayesian Networks and a maintenance model based on continuous time Markov chains, and they propose to combine them according to a compositional multi-formalism modelling approach in order to analyze the impact of imperfect maintenance on the system safety. Ale et al. present the structure and backbone of a causal model of air traffic safety. The backbone consists of a string of 36 separate accident categories with repetitions in each flight phase, which are based on a study of accidents and incidents over two decades. The probabilities of the various accident pathways are first quantified using fault-trees developed from accidents and incident reports. A model for the error probability of crew members has been developed and quantified using expert judgement elicitation techniques. The model is integrated in a single integrated Bayesian Belief Net, which allows consistent handling of probabilities and their interdependence. The paper by Antonioni, Bonvicini, Spadoni and Cozzani addresses tools needed to build up a general framework allowing the extension of quantitative risk assessment procedure to include the analysis of the industrial accidents caused by natural events. Specific methods and models are developed to allow the quantitative assessment of risk caused by two categories of ‘‘Na-Tech’’ accidents: accidents triggered by earthquakes and
ARTICLE IN PRESS 1370
Editorial / Reliability Engineering and System Safety 94 (2009) 1369–1370
accidents triggered by floods. The approach allows the calculation of the overall individual and societal risk indices including the multiple-failure scenarios caused by the impact of natural events. Dome´nech, Escriche and Martorell address food safety. The paper describes a methodology for measuring the effectiveness of a Critical Control Point (CCP) in terms of the risk to consumer health as well as the potential impact of company revenues. The method gives the decision-maker a quantitative tool for setting critical limits and monitoring variations at a CCP. This would allow risk management decisions to be made at-line (i.e., real time) during a specific process. Ha¨ring, Scho¨nherr and Richter study quantitative hazard and risk analysis for fragments of high-explosive shells in air. The analysis covers scenario analysis, probabilistic analysis, physical consequence analysis and damage analysis. Vulnerability models determine the individual local risk. Risk criteria are used for making judgements about the risk. Stoop and Roed-Larsen give a historical overview of developments in accident investigations in the transport industry. In particular differences among human operator models, the allocation of responsibilities across stakeholders, their power relations and tools are elaborated. The need and opportunities for a transition from accident prevention towards systems change are indicated. Kuniewski, van der Weideand van Noortwijk present a sampling-inspection strategy for the evaluation of time-depen-
dent reliability of deteriorating systems, where the deterioration is assumed to initiate at random times and at random locations. Aven and Flage consider decision problems related to production assurance and safety. The issue is to what extent we should use decision criteria based on expected values, such as the expected net present value and the expected cost per expected number of saved lives to guide the decision. Such criteria are recognised as practical tools for supporting decision-making under uncertainty, but the question is to what extent uncertainty is adequately taken into account by these criteria. Finally, we would like to thank all contributing authors for their papers, as well as all the reviewers who have helped the authors to improve the papers. We hope that the issue provides an interesting and a useful insight into important topics within reliability engineering and system safety. Terje Aven, Jan Erik Vinnem University of Stavanger, Norway Carlos Guedes Soares Technical University of Lisbon, Instituto Superior Tecnico, Lisboa, Portugal E-mail address: [email protected] Available online 10 February 2009
Corresponding author.