An Efficient Context-Sensitive Service Composition Framework for Precise Controlling in Cyber-Physical Systems

This paper presents definitions characterizing the concepts regarding cyber-physical systems and dependability. Cyber-physical systems incorporate computing, communication and storage capabilities with monitoring and/or control of entities in the physical world in a dependably, securely, efficiently and real-time way. The challenges of cyber-physical system research are concerning: real-time system abstractions; robustness, safety and security; QoS composition; and nor least dependability. Dependability is first introduced as a global concept that subsumes the usual attributes of reliability, availability, safety, integrity and maintainability. The paper aims to define research challenges to achieve the dependability in cyber-physical hydropower systems. The significant challenge of the dependability in cyber-physical hydropower systems is evaluation of the system behavior in terms of interdependencies between cyber and physical components of the system.

CPS is complex distributed systems, which contain computing, communications, and control. CPS is a product of the combination of physical world and the cyber world. The cyber world needs a lot of physical equipment to deal with perception and communication, then collect and transfer the information in the real environment, and by computation to forecast what might happen in future real environment, at last through the control strategy to achieve the optimal solution. In short, cyber physical system is the complex systems combination with computation system, sensory system and control system. Cyber physical system through more extensive connection, the physical world more thorough cognition, more effectively control the physical world, make the information world and the physical world closer integration, realize coordination awareness and control of the physical world. The paper through the analysis of the human perception system, build a cyber-physical fusion system based on human perception architecture.

Web Services are materialized as a major technology carried out for automated interaction between distributed and miscellaneous applications. It is defined as a software service that provides business solutions consumed by different service requester. It can be accessed by a standard web protocol. Service composition is the mechanism used for selecting, reusing and combining existing web services to build new web services. With immense increase in web services, quality assessment plays an essential role in the selection approach. QoS is defined as the ability to guarantee the requirements like latency, reliability, bandwidth, etc. in order to satisfy a service level agreement between an application provider and end-user. QoS based dynamic service composition leads to the upward growth of an organization that implements multiple services to provide its business solution. The proposed research work elaborates the research work on different methodologies of QoS prediction with its implications to provide a proper road map for future research on efficient service composition.

Though the deep penetration of cyber systems across the smart grid sub-domains enrich the operation of the wide-area protection, control, and smart grid applications, the stochastic nature of cyber-attacks by adversaries inflict their performance and the system operation. Various hardware-in-the-loop (HIL) cyber-physical system (CPS) testbeds have attempted to evaluate the cyberattack dynamics and power system perturbations for robust wide-area protection algorithms. However, physical resource constraints and modular integration designs have been significant barriers while modeling large-scale grid models (scalability) and have limited many of the CPS testbeds to either small-scale HIL environment or complete simulation environments. This paper proposes a meticulous design and efficient modeling of IEC-61850 logical nodes in physical relays to simulate large-scale grid models in a HIL real-time digital simulator environment integrated with industry-grade hardware and software systems for wide-area power system applications. The proposed meticulous design includes multi-breaker emulation in the physical relays, which extends the capacity of a physical relay to accommodate more number of CPS interfaces in the HIL CPS security testbed environment. We have used our existing HIL CPS security testbed to demonstrate scalability by the real-time performance of ten simultaneous IEEE-39 CPS grid models. The experiments demonstrated significant results by 100% real-time performance with zero overruns, and low latency while receiving and executing control signals from physical SEL relays via IEC-61850 and DNP-3 protocols to real-time digital simulator, substation remote terminal unit (RTU) software and supervisory control and data acquisition (SCADA) software at control center.

Service composition allows multimedia services to be automatically composed from atomic service components based on dynamic service requirements. Previous work falls short for distributed multimedia service composition in terms of scalability, flexibility and quality-of-service (QoS) management. In this paper, we present a fully decentralized service composition framework, called SpiderNet, to address the challenges. SpiderNet provides statistical multiconstrained QoS assurances and load balancing for service composition. Moreover, SpiderNet supports directed acyclic graph composition topologies and exchangeable composition orders. We have implemented a prototype of SpiderNet and conducted experiments on both wide-area networks and a simulation testbed. Our experimental results show the feasibility and efficiency of the SpiderNet service composition framework.

Security and Privacy Aspect of Cyber Physical Systems

Online services encapsulate enterprises, people, software systems and often operate in poorly understood environments. Using such services in tandem to predictably orchestrate a complex task is one of the principal challenges of service-oriented computing. A composite service orchestration soliciting multiple atomic services is plagued by a number of sources of variation. For instance, availability of an atomic service and its response time are two important sources of variation. Moreover, the number of possible variations in a composite service increases exponentially with increase in the number of atomic services. Testing such a composite service presents a crucial challenge as its often very expensive to exhaustively examine the variation space. Can we effectively test the dynamic behavior of a composite service using only a subset of these variations? This is the question that intrigues us. In this paper, we first model composite service variability as a feature diagram (FD) that captures all valid configurations of its orchestration. Second, we apply pairwise testing to sample the set of all possible configurations to obtain a concise subset. Finally, we test the composite service for selected pairwise configurations for a variety of QoS metrics such as response time, data quality, and availability. Using two case studies, Car crash crisis management and eHealth management, we demonstrate that pairwise generation effectively samples the full range of QoS variations in a dynamic orchestration. The pairwise sampling technique eliminates over 99% redundancy in configurations, while still calling all atomic services at least once. We rigorously evaluate pairwise testing for the criteria such as: a) ability to sample the extreme QoS metrics of the service b) stable behavior of the extracted configurations c) compact set of configurations that can help evaluate QoS tradeoffs and d) comparison with random sampling.

Energy-aware service composition in multi-Cloud

The evolution and application of intelligence have been discussed from perspectives of life, control theory and artificial intelligence. However, there has been no consensus on understanding the evolution of intelligence. In this study, we propose a Tri-X Intelligence (TI) model, aimed at providing a comprehensive perspective to understand complex intelligence and the implementation of intelligent systems. In this work, the essence and evolution of intelligent systems (or system intelligentization) are analyzed and discussed from multiple perspectives and at different stages (Type I, Type II and Type III), based on a Tri-X Intelligence model. Elemental intelligence based on scientific effects (e.g., conscious humans, cyber entities and physical objects) is at the primitive level of intelligence (Type I). Integrated intelligence formed by two-element integration (e.g., human-cyber systems and cyber-physical systems) is at the normal level of intelligence (Type II). Complex intelligence formed by ternary-interaction (e.g., a human-cyber-physical system) is at the dynamic level of intelligence (Type III). Representative cases are analyzed to deepen the understanding of intelligent systems and their future implementation, such as in intelligent manufacturing. This work provides a systematic scheme, and technical supports, to understand and develop intelligent systems.

Cyber-Physical Systems (CPSs) represent a new generation of digital systems, where cyber entities and physical devices cooperate towards a set of common goals. The continuously evolving requirements concerning CPSs have led to the necessity of creating a dependability assurance framework. The present paper introduces a methodology for creating a dependability run-time model of CPSs in a dynamic and evolving context. The new model combines ontology development techniques with a fault forecasting analysis process in order to define a dependability domain ontology, which plays a central role in the CPS architecture and drives various aspects of these systems, especially the ones related to system diagnosis. An ontology-driven CPS for environmental monitoring shows how the proposed approach is able to assure system dependability. The environmental monitoring case study CPS in this paper has an open architecture with a high degree of flexibility and scalability, it is composed of wireless sensors nodes for data acquisition and transfer, and it includes the ontology and specific software packages for the CPS proper operation.

Cyber-physical systems are a kind of emerging large-scale distributed systems that are integrations of computation, networking, and physical worlds. Cyber physical systems are increasing scale and complexity with the growing pervasiveness of ICT and the development of the smart worlds such as smart factory, smart robotics, smart grids, smart cities, smart vehicles, smart healthcare systems, and smart homes. The growing interconnection of physical and virtual worlds of complex cyber physical systems, and the development of increasingly sophisticated intelligence techniques, has given rise to the next generation of CPS, that is referred to as smart cyber-physical systems (sCPS) which can efficiently operate, manage and control physical world and virtual world, and offer broad range of novel applications and services. Thus, smart cyber physical systems are complex cyber physical systems endowed with intelligent abilities. The main characteristic of such a new generation of smart cyber physical systems is the ability to interact with the physical worlds and adapt to new working environments through distributed intelligent mechanisms that executing and operating at the unit (single device), cluster (groups of devices) and network level (the network of devices). The properties like uncertainties, safety, reliability, and performance requirement, spatial-temporal requirement, and adaptation ability are very important, modeling smart cyber-physical systems must face these challenges and satisfy these specific requiremnts. In order to specify and model such kind of systems, we propose a new paradigm for specifying and modeling smart cyber physical systems based on software defined approach using Modelicaml. Software defined approach is a new way that help abstract the real world and virtual world with software components, this approach can simplify system specification, modeling and design. The main aim of ModelicaML is to enable an efficient and effective way to use Modelica, UML and SysML models reusing notations that are also used for software modeling based on software defined approach. The effectiveness of the approach is demonstrated with a case study of Vehicular Ad-hoc NETwork.

Service-Oriented Computing (SOC), a main trend in software engineering, promotes the construction of applications based on the notion of services. SOC has recently attracted a great deal of attention from researchers, and has been comprehensively adopted by industry. However, service composition enabling the aggregation of existing services into composite services still imposes a great challenge to service-oriented technology. Web service composition requires component Web services to be available in request, to behave correctly in operation, and to be replaceable flexibly in failure. Although availability of Web services plays a crucial role in building robust SOC-based applications, it has been largely neglected, especially for service composition. In this chapter, we propose a service composition framework that integrates a set of composition-based service discovery mechanisms, a user-oriented service delivery approach, as well as a service management mechanism for composite services.

Web service composition provision which requires efficient coordination of the execution of component services is a critical issue in service-oriented computing. Nowadays, BPEL4WS, the de facto industry standard for service compositions, is predominantly deployed in a way in which all interactions and intermediate data must go through one server. This centralised management results in problems such as poor performance, impaired reliability, limited scalability, and restricted flexibility. To address these problems, this research proposes an agent-based decentralised process management framework for Web service composition. This framework allows distributed BPEL engines, each of which is represented by a software agent, to manage the execution of relevant sub-processes, and to interact with one another directly to coordinate the execution of the whole process. Such a framework naturally reflects the distributed and dynamic features of the Web services environment and subsequently offers improved coordination support for service composition provision.

“Cyber-physical systems” (CPS) is a term that describes integrating physical processes with computational systems to create intelligent and interconnected systems. This research focuses on two core components of CPS: the cyber and the physical layers, and how the two layers work in collaboration to drive innovation across healthcare and energy management. It also includes architectural design principles, enabling technologies, and key applications, such as smart cities, autonomous vehicles, and industrial automation. It discusses the challenges faced during CPS development, such as real-time constraints, interoperability, cybersecurity risks, and ethical considerations, making for a comprehensive view of the challenges and opportunities in the field. Finally, the study concludes with a forward-looking perspective on the transformative potential of CPS, making its critical role in defining the future of industries, technological advancements, and social progress clear. As the journey of CPS continues forward, its integration into digital twins, metaverse applications, and Industry 5.0 will redefine interaction with technology, pushing innovation and efficiency to new levels. This chapter will provide a deep dive into the state of the art and the future directions for CPSs, providing some insights that are useful to researchers, practitioners, and students in the field for the next generation of technological advancements.

As computers and communication bandwidth become ever faster and cheaper, computing and communication capabilities are embedded in all types of objects and structures in the physical environment. Harnessing these capabilities to bridge the cyber-world with the physical world will allow the development of applications with great societal impact and economic benefit. At the heart of these applications are cyber-physical systems consisting of integrated computational and communication cores that interact with the physical world, with intelligence provided by embedded software. Cyber Physical Systems (CPS) are engineered systems that provide tight integration of and coordination between the cyber world of computing and communications and the physical world. CPS are to meet the needs of the new generation of engineered systems that are highly dependable, efficiently produced and certified, and capable of advanced performance in computation, communication, and control. CPS will transform how we interact with and control the physical world around us, as the Internet transformed how we interact and communicate with one another and revolutionized how and where we access information. One application domain of CPS is Medical Cyber-Physical Systems (MCPS), which are life-critical, context-aware, networked systems of medical devices. Medical device industry is undergoing a transformation, embracing the potential of embedded software and network connectivity. Instead of stand-alone devices that can be designed, certified, and used to treat patients independent of each other, distributed systems that simultaneously control multiple aspects of the patient's physiology are increasingly used in hospitals to provide high-quality continuous care for patients. The combination of embedded software controlling medical devices, networking capabilities, and complicated physiological dynamics of patient bodies makes MCPS complex. The need to design complex MCPS that are both safe and effective presents numerous challenges, including achieving high assurance in system software, interoperability, context-aware intelligence, autonomy, security and privacy, and device certification. In this talk, I will discuss these challenges in developing MCPS and present some of our work in addressing them, and several open research and development issues.