Control of Discrete-event Systems provides a survey of the most important topics in the discrete-event systems theory with particular focus on finite-state automata, Petri nets and max-plus algebra. Coverage ranges from introductory material on the basic notions and definitions of discrete-event systems to more recent results. Special attention is given to results on supervisory control, state estimation and fault diagnosis of both centralized and distributed/decentralized systems developed in the framework of the Distributed Supervisory Control of Large Plants (DISC) project. Later parts of the text are devoted to the study of congested systems though fluidization, an over approximation allowing a much more efficient study of observation and control problems of timed Petri nets. Finally, the max-plus algebraic approach to the analysis and control of choice-free systems is also considered. Control of Discrete-event Systems provides an introduction to discrete-event systems for readers that are not familiar with this class of systems, but also provides an introduction to research problems and open issues of current interest to readers already familiar with them. Most of the material in this book has been presented during a Ph.D. school held in Cagliari, Italy, in June 2011. This book constitutes the refereed proceedings of the Third International Workshop on Tools and Algorithms for the Construction and Analysis of Systems, TACAS '97, held in Enschede, The Netherlands, in April 1997. The book presents 20 revised full papers and 5 tool demonstrations carefully selected out of 54 submissions; also included are two extended abstracts and a full paper corresponding to invited talks. The papers are organized in topical sections on space reduction techniques, tool demonstrations, logical techniques, verification support, specification and analysis, and theorem proving, model checking and applications. The refereed proceedings of the 24th International Conference on Applications and Theory of Petri Nets, ICATPN 2003, held in Eindhoven, The Netherlands, in June 2003. The 25 revised full papers presented together with 6 invited contributions were carefully reviewed and selected from 77 submissions. All current issues on research and development in the area of Petri nets are addressed, in particular concurrent systems design and analysis, model checking, networking, business process modeling, formal methods in software engineering, agent systems, systems specification, systems validation, discrete event systems, protocols, and prototyping. The contents of this volume are application oriented. The volume contains a de tailed presentation of 19 applications of CP-nets, covering a broad range of ap plication areas. Most of the projects have been carried out in an industrial set ting.

Coloured Petri Nets Basic Concepts, Analysis Methods and Practical Use

There continue to be numerous breaches publicised pertaining to cybersecurity despite security practices being applied within industry for many years. This paper is intended to be the first in a number of papers as research into cybersecurity assurance processes. This paper is compiled based on current research related to cybersecurity assurance and the impact of the human element on it. The objective of this work is to identify elements of cybersecurity that would benefit from further research and development based on the literature review findings. The results outlined in this paper present a need for the cybersecurity field to look in to established industry areas to benefit from effective practices such as human reliability assessment, along with improved methods of validation such as statistical quality control in order to obtain true assurance. The paper proposes the development of a framework that will be based upon defined and repeatable quantification, specifically relating to the range of human aspect tasks that provide or are intended not to negatively affect cybersecurity assurance. Copyright © 2016 John Wiley & Sons, Ltd.

Human behaviour as an aspect of cybersecurity assurance

There continue to be numerous breaches publicised pertaining to cyber security despite security practices being applied within industry for many years. This article is intended to be the first in a number of articles as research into cyber security assurance processes. This article is compiled based on current research related to cyber security assurance and the impact of the human element on it. The objective of this work is to identify elements of cyber security that would benefit from further research and development based on the literature review findings. The results outlined in this article present a need for the cyber security field to look in to established industry areas to benefit from effective practices such as human reliability assessment, along with improved methods of validation such as statistical quality control in order to obtain true assurance. The article proposes the development of a framework that will be based upon defined and repeatable quantification, specifically relating to the range of human aspect tasks that provide, or are intended not to negatively affect cyber security posture.

Human Behaviour as an aspect of Cyber Security Assurance

HEART-IS: A Novel Technique for Evaluating Human Error-Related Information Security Incidents

Components are "hot," and changing at a fast pace. Here are industry forecasts from two leaders in the field, as well as their choices for inclusion in this focus: a state-of-the-practice overview and some of the latest work in CBSE.

Component-Based Software Engineering

Industrial control systems are safety-critical systems. However, security attacks aiming at industrial control systems are rising tremendously in recent years. As a result, not only safety but also security should be considered in industrial control systems. To protect industrial control systems from failing due to intentional attacks from outside of the system and internal faults, safety and security must be considered comprehensively for the two following reasons: Firstly, it is security attacks from outside of the system that weaken inside equipment, which then leads to safety issues. This means that safety and security are related. Secondly, safety and security are two different areas with their own focuses. When trying to achieve their separate goals in the same industrial control system, safety requirements and security requirements may be conflicted. Therefore it is necessary to study the relationship between safety and security and consider them comprehensively. In this paper, we focus on requirement analysis phase. The relationships between safety and security requirements are analyzed and classified. An integrated requirement analysis method is proposed to extract interdependent safety and security requirements and resolve conflicted safety and security requirements. Finally, two examples are given to show how to use the proposed method.

Extracting interdependent requirements and resolving conflicted requirements of safety and security for industrial control systems

With the increasing complexity of software-intensive systems, software failures have become the dominant cause of overall system failures. To ensure runtime reliability, researchers have come up with online failure prediction techniques to predict potential software failures in advance and these provide the basis for subsequent online fault management and other health management activities. Failure indicators are the abnormal system variables that indicate potential failures, which are the basis of failure prediction. However, in previous failure prediction studies, researchers have focused mainly on failure indicators at the hardware level, network level, or operating system level, ignoring application-level failure indicators. Furthermore, there is no systematic model for failure indicators, which means that failure indicators lack a precise definition and the use of failure indicators is quite arbitrary. This paper proposes a systematic modeling approach for failure indicators of complex software-intensive systems. Firstly, failure indicators at the application level are extracted based on the analysis of new features of complex software-intensive systems. Then, failure indicators at all levels are summarized and classified into several categories. In addition, these indicators are analyzed, and their features are extracted from different dimensions, including the time/space domain, system/application dimension, and from the internal/external viewpoint. Based on these different attributes from different dimensions, a systematic modeling approach based on set theory is proposed to depict these failure indicators accurately and to provide a guideline for selecting appropriate failure indicators. Finally, some examples are given to show how to use the proposed method and to verify its effectiveness.

A Systematic Modeling Approach for Failure Indicators of Complex Software-Intensive Systems

As with the increase of software complexity, software failure has become an important threat to the reliability of software intensive systems. Software fault propagation behaviors, which are prevalent in complex software systems, have a ubiquitous influence on software reliability design and evaluation process. Software fault propagation is a necessary condition for the failure of complex software systems. It is of great significance to investigate it to improve the reliability of software systems. This paper investigates existing software fault propagation analysis methods and gives a taxonomy of existing fault propagation analysis methods, which can be used to understand these methods well. After that, several typical fault propagation analysis methods are introduced according to different analysis levels. This survey also finds that researchers tend to use methods which have a high degree of abstraction, such as entropy measurement, complex network methods, and system engineering methods, to deal with the fault propagation analysis in software intensive systems. Finally, several shortcomings are listed and the future trends of fault propagation analysis are emphasized.

Fault propagation analysis in software intensive systems: A survey

Information security risk assessment is the premise and basis for ensuring the security of information systems. Current research on risk assessment focuses on the calculation methods and assessment models of the risk value. Also, lots of automatic assessment tools have been applied to risk assessment. However, these methods didn't take human errors in risk assessment work into consideration, thus couldn't solve the problem brought by the influence of human errors on final assessment results. As a result, this paper introduces the Technique for Human Error Rate Prediction (THERP) which is a mature technique in human reliability analysis into the process of information security risk assessment. Combined with current analysis techniques of human errors in computer science and aiming at the calculation process of the risk value of important assets in information security risk assessment, research on the calculation method of risk value considering human reliability is carried out in this paper. The calculation method of human error rates in the entire process of risk value calculation is proposed. An example is provided to verify the method proposed in this paper.

Research on the calculation method of information security risk assessment considering human reliability

Current SFTA methods highly rely on the experience of analysts and it's difficult to reuse history information of SFTA for current methods. With the increase of software complexity, the scale of software fault tree has increased explosively. Thus, there is an urgent need to effectively reuse history information of SFTA in order to avoid repeating analysis and improve efficiency. To organize fault tree information effectively, mine valuable patterns from history information and reuse SFTA information, this paper proposed a reuse-oriented auxiliary construction method for software fault tree. Firstly, a semi-formal method is proposed to define software fault tree information, which includes elements such as node, relation, type, target function and target software module. Then a knowledge base for software fault tree information is constructed. History information is indexed and reconstructed from several different attribute dimensions. Finally, by text matching and intelligent linking, a reusable sub fault tree is generated automatically from the knowledge base and can be inserted into another fault tree, achieving the goal of reusing SFTA information. The method proposed in this paper can effectively provide aid for SFTA, improve analysis efficiency and increase automation degree. Meanwhile, a tool based on this method is introduced in the paper, which also includes some other useful features such as automatic alignment of nodes, rule checking, minimal cut set calculation, qualitative analysis, and report generation. An example is provided in the paper to demonstrate how to use this method and validate the applicability, validity and efficiency of this method.

Luyi Li

Papers

Extracting interdependent requirements and resolving conflicted requirements of safety and security for industrial control systems

A Systematic Modeling Approach for Failure Indicators of Complex Software-Intensive Systems

Fault propagation analysis in software intensive systems: A survey

Research on the calculation method of information security risk assessment considering human reliability

A reuse-oriented auxiliary construction method for software fault tree and tool implementation