Aspects Of Cyber-physical Systems Research Articles

Towards a Holistic and Functional Model-Based Design Method for Mechatronic Cyber-Physical Systems

AbstractEngineering cyber-physical systems (CPS) is complex and time-consuming due to the heterogeneity of the involved engineering domains and the high number of physical and logical interactions of their subsystems. Model-based systems engineering (MBSE) approaches tackle the complexity of developing CPS by formally and explicitly modeling subsystems and their interactions. Newer approaches also integrate domain-specific models and modeling languages to cover different aspects of CPS. However, MBSE approaches are currently not fully applicable for CPS development since they do not integrate formal models for physical and mechanical behavior to an extent that allows to seamlessly link mechanical models to the digital models and reuse them. In this paper, we discuss the challenges arising from the missing integration of physics into MBSE and introduce a model-based methodology capable of integrating physical functions and effects into an MBSE approach on a level where detailed physical effects are considered. Our approach offers a fully virtual, model-based development methodology covering the whole development process for the development of CPS. Evaluating this methodology on a real automotive use case demonstrates benefits regarding virtual development and functional testing of CPS. It shows potentials regarding automated development and continuous integration of the whole CPS including all domains. As an outlook of this paper, we discuss potential further research topics extending our development workflow.

A Survey of Cyber-Physical Systems From a Game-Theoretic Perspective

With the emergence of the Internet-of-Things (IoT), artificial intelligence, and communication technologies, cyber-physical systems (CPS) have revolutionized the engineering paradigm with profound applications in many aspects of society including homes, energy, agriculture, health-care, transportation, business, and manufacturing. A CPS uses suitable computational techniques such as game theory to enable different entities to interact with one another for taking necessary actions to obtain selected objectives. Recent literature on CPS has extensively used game theory to approach a variety of technical challenges. In order to make these contributions more accessible to a broader audience, there is a need for studies that can provide readers with a comprehensive understanding of different types of CPS and their attributes, then clearly outline why game theory is relevant for modeling different aspects of CPS, and also discuss how game theory has been used in relevant literature to date. This paper bridges this gap by 1) providing a general discussion of different types of CPS and their characteristics; 2) giving an overview of different types of game-theoretic approaches; 3) explaining why game theory is appropriate for modeling different types of CPS; and 4) finally, studying how game theory has been used in different CPS types to address their challenges. Further, we also identify some key research challenges for future investigation where game theory could be applied as a potential solution.

Unified IT&OT Modeling for Cybersecurity Analysis of Cyber-Physical Systems

Cyber-Physical Systems (CPSs) engineering profoundly relies on modeling methods to represent the system and study the operation and cybersecurity of CPSs. The operation of a CPS is the result of the collaboration between Information Technology (IT) and Operational Technology (OT) components. While OT focuses on the system's process physics, the emphasis of IT is on information flow. Consequently, different system models are utilized to study various aspects of CPSs, which may infer different views of the same system. The increasing complexity of CPSs and the high number of cyberattacks against Industrial Control Systems (ICSs) and CPSs in recent years have highlighted the necessity of considering these interrelations based on a unified model to analyze cybersecurity of CPSs. However, the diversity of engineering fields and implicit relations and dependencies between them have made it difficult to integrate the modeling methods towards a unified IT&OT model of CPSs.In this paper, we propose a comprehensive method, based on bond graphs, to model CPS and analyze their cybersecurity. Unlike existing methods, modeling the cyber layer along with the physical layer based on the system flow provides a holistic graphical representation of a CPS, which facilitates collaboration between IT and OT experts.

Operator Suspicion and Decision Responses to Cyber-Attacks on Unmanned Ground Vehicle Systems

Cyber-attacks against cyber-physical systems (CPS), such as unmanned vehicles, are emergent threats with potentially catastrophic impacts, and this issue has drawn considerable interest by military agencies. Abundant body of research has attempted to address the physical security aspects of CPS; however, research addressing the human dimensions of cyber-attack detection and responses from an operator and operational perspective is sparse. This research has provided a novel probe into the human factors affecting operator resilience in responding to cyber-attacks, which are situations characterized by uncertainty and malicious intent. The variability of individual operators makes it improbable to grasp the full range of factors contributing to operator performance; however, the application of Suspicion Theory as proposed by Bobko et al. (2013), provides a starting point to aid in understanding operator performance in situations involving malicious intent (e.g. a cyber-attack). According to the theory, malicious intent is a critical component of operator suspicion, which is a key factor in operator response to cyber-attacks. The current research explored this human dimension through scenario-based, human-in-the-loop simulation experiments with Air Force personnel. It included both abstract and empirical assessments of the application of Suspicion Theory to operator detection and responses to cyber-attacks against an unmanned vehicle system, and it took a systems-oriented approach to the problem by considering the interaction of a Human-Machine Team (HMT) in the response. The HMT here refers to an operator and a Sentinel, which is an automated cyber-attack detection aid. The study evaluated the effects of suspicion, as well as the effects of perceived consequence, on the operator, and the resulting HMT quality of performance in responding to alerts, including both false alarms and properly detected cyber-attack scenarios. The findings show that Sentinel alerts alone do not create operator suspicion. Instead, alerts can serve as a catalyst for a wider information search by the operator, which, on a situational basis can lead to formation of increased operator suspicion. The analysis of experimental results pointed to a negative correlation between operator suspicion and performance score that measured the quality of a response to the given scenario. In addition, a strong correlation between HMT performance score and task response time was noted.

Design science research towards resilient cyber-physical eHealth systems

Most eHealth systems are cyber-physical systems (CPSs) making safety-critical decisions based on information from other systems not known during development. In this design science research, a conceptual resilience governance framework for eHealth CPSs is built utilizing 1) cybersecurity initiatives, standards and frameworks, 2) science of design for software-intensive systems and 3) empowering cyber trust and resilience. According to our study, a resilient CPS consists of two sub-systems: the proper resilient system and the situational awareness system. In a system of CPSs, three networks are composed: platform, software and social network. The resilient platform network is the basis on which information sharing between stakeholders could be created via software layers. However, the trust inside social networks quantifies the pieces of information that will be shared - and with whom. From citizens’ point of view, eHealth is wholeness in which requirements of information security hold true. Present procedures emphasize confidentiality at the expense of integrity and availability, and regulations/instructions are used as an excuse not to change even vital information. The mental-picture of cybersecurity should turn from “threat, crime, attack” to “trust” and “resilience”. Creating confidence in safe digital future is truly needed in the integration of the digital and physical world’s leading to a new digital revolution. The precondition for the exchange of information “trust” must be systematically built at every CPS’ level. In health sector, increasingly interconnected social, technical and economic networks create large complex CPSs, and risk assessment of many individual components becomes cost and time prohibitive. When no-one can control all aspects of CPSs, protection-based risk management is not enough to help prepare for and prevent consequences of foreseeable events, but resilience must be built into systems to help them quickly recover and adapt when adverse events do occur.

Guest Editorial Special Section on Control and Automation From the 2015 International Conference on Cyber-Physical Systems (ICCPS)

The papers included in this special section were presented at the Sixth Annual ACM/IEEE International Conference on Cyber-Physical Systems (ICCPS 2015) that was held on April 14–16, 2015 in Seattle, WA, USA, as part of the Eighth Annual Cyber-Physical Systems Week. ICCPS is the premier single-track conference for reporting advances in all aspects of cyber-physical systems, including theory, tools, applications, systems, testbeds, and field deployments. Its focus includes the core science and technology for developing fundamental principles that underpin the integration of cyber and physical elements, with application domains that include transportation, energy, water, agriculture, ecology, supply-chains, medical and assistive technology, sensor and social networks, and robotics.