Cyber-physical Systems Software Research Articles

Multi-Model Workload Specifications and their application to Cyber-Physical Systems

Abstract To address the question of how to deliver time-sensitive software for Cyber-Physical Systems (CPS) requires a range of modelling and analysis techniques to be developed and integrated. A number of these required techniques are unique to time-sensitive software where timeliness is a correctness property rather than a performance attribute. This paper focuses on how to obtain worst-case estimates of the software’s execution time; in particular, it considers how workload models are derived from assumptions about the system’s run-time behaviour. The specific contribution of this paper is the exploration of the notion that a system can be subject to more than one workload model. Examples illustrate how such multi-models can lead to improved schedulability, and hence more efficient CPS. An important property of the approach is that the derived analysis exhibits model-bounded behaviour. This ensures that the maximum load on the system is never higher than that implied by the individual models.

A type system for formal verification of cyber-physical systems C/C++ software

The subject: This study focuses on improving the quality of Cyber-Physical System (CPS) software by eliminating incorrect usage of units of measurement and orientation in C/C++ programs. Incorrect usage often leads to critical errors that conventional systems cannot effectively prevent. Manual examination of code using dimensional and orientation analysis can detect these errors in physical equations, but these methods become impractical when dealing with complex physical computations. Objectives: As suggested by Siano, the proposed approach uses physical quantities and prefixes defined by the International System of Units and orientation operations on physical objects. The elaborated system incorporates dimensional and orientation analysis and metaprogramming techniques. The methods used are dimensional & orientational analysis and metaprogramming. The following results were obtained: ensuring consistency of the units, incorporating orientation operations into the programming model for accurately handling physical object rotations and alignments, and using Siano’s work to precisely manipulate object orientation, thereby reducing the likelihood of orientation-related errors. Checking physical dimensions and orientations during the compilation stage identifies potential software defects before code execution, thereby reducing debugging time and lowering the cost of addressing issues later in development. The elaborated system represents a crucial step towards safer and more dependable Cyber-Physical System applications. This approach allows us to identify approximately 90% of incorrect usage of program variables; additionally, it detects over 50% of erroneous operations during compilation and execution of large-scale programs in real-world conditions. Conclusions. Scientific novelty: it proposed and developed a specialized C++-type library for formal compile-time software verification of Cyber-Physical Systems software. The proposed C++-type library leverages dimensional and orientational analysis to enhance software quality, reliability, and real-time formal verification. Although the proposed method for formal verification is not tailor-made for cyber-physical objects and systems, given its primary focus on software-level concerns, it does exhibit adaptability for verifying general-purpose software that incorporates various physical parameters. This versatility extends to diverse domains such as educational, gaming, and simulation software.

Depend Ability Analysis on CPS Using Machine Learning Techniques

A Cyber-Physical System (CPS) is an entity that effortlessly monitors and controls physical operations by integrating computational and physical elements. Dependability on the CPS application program and also proposes a real-time analysis approach to CPS application dependability based upon Artificial Intelligence and Machine Learning (ML). For starters, pick complicated networks to determine tips within the system topology on the CPS application process. Unsupervised mastering category by a quick density clustering algorithm to classify the value of nodes could be successfully put on the crucial analysis of nodes in CPS application program as well as help support the setting up of CPS software phone Secondly, a real-time CPS dependability automated internet analysis technique is suggested. Unreliable methods are able to imply big losses, each monetarily in addition to within man's life. On a good mention, CPS has information like the main component of the operation of theirs. The prevalence and availability of information demonstrate a brand-new chance to change the methods within what dependability evaluation continues to be usually performed. This process utilizes printer mastering tips to create an analysis framework, design, and style an internet queuing algorithm, as well as put into action real-time internet evaluation and analysis of CPS dependability. Preventive steps make sure that the device works ordinarily as well as with no interruption, which significantly betters method dependability. Last but not least, simulation final results verify the usefulness of the analysis technique and the broad application prospects of its.

Towards DevOps for Cyber-Physical Systems (CPSs): Resilient Self-Adaptive Software for Sustainable Human-Centric Smart CPS Facilitated by Digital Twins

The Industrial Revolution drives the digitization of society and industry, entailing Cyber-Physical Systems (CPSs) that form ecosystems where system owners and third parties share responsibilities within and across industry domains. Such ecosystems demand smart CPSs that continuously align their architecture and governance to the concerns of various stakeholders, including developers, operators, and users. In order to satisfy short- and long-term stakeholder concerns in a continuously evolving operational context, this work proposes self-adaptive software models that promote DevOps for smart CPS. Our architectural approach extends to the embedded system layer and utilizes embedded and interconnected Digital Twins to manage change effectively. Experiments conducted on industrial embedded control units demonstrate the approach’s effectiveness in achieving sub-millisecond real-time closed-loop control of CPS assets and the simultaneous high-fidelity twinning (i.e., monitoring) of asset states. In addition, the experiments show practical support for the adaptation and evolution of CPS through the dynamic reconfiguring and updating of real-time control services and communication links without downtime. The evaluation results conclude that, in particular, the embedded Digital Twins can enhance CPS smartness by providing service-oriented access to CPS data, monitoring, adaptation, and control capabilities. Furthermore, the embedded Digital Twins can facilitate the seamless integration of these capabilities into current and future industrial service ecosystems. At the same time, these capabilities contribute to implementing emerging industrial services such as remote asset monitoring, commissioning, and maintenance.

Towards Building Verifiable CPS using Lingua Franca

Formal verification of cyber-physical systems (CPS) is challenging because it has to consider real-time and concurrency aspects that are often absent in ordinary software. Moreover, the software in CPS is often complex and low-level, making it hard to assure that a formal model of the system used for verification is a faithful representation of the actual implementation, which can undermine the value of a verification result. To address this problem, we propose a methodology for building verifiable CPS based on the principle that a formal model of the software can be derived automatically from its implementation. Our approach requires that the system implementation is specified in Lingua Franca (LF), a polyglot coordination language tailored for real-time, concurrent CPS, which we made amenable to the specification of safety properties via annotations in the code. The program structure and the deterministic semantics of LF enable automatic construction of formal axiomatic models directly from LF programs. The generated models are automatically checked using Bounded Model Checking (BMC) by the verification engine Uclid5 using the Z3 SMT solver. The proposed technique enables checking a well-defined fragment of Safety Metric Temporal Logic (Safety MTL) formulas. To ensure the completeness of BMC, we present a method to derive an upper bound on the completeness threshold of an axiomatic model based on the semantics of LF. We implement our approach in the LF V erifier and evaluate it using a benchmark suite with 22 programs sampled from real-life applications and benchmarks for Erlang, Lustre, actor-oriented languages, and RTOSes. The LF V erifier correctly checks 21 out of 22 programs automatically.

Runtime System Support for CPS Software Rejuvenation

Software rejuvenation, which was originally introduced to deal with performance degradation due to software aging, has recently been proposed as a mechanism to provide protection against run-time cyber attacks in cyber-physical systems (CPSs). Experiments have demonstrated that CPSs can be protected from attacks that corrupt run-time code and data by periodically restoring the run-time system with an uncorrupted image. Control theoretic and empirical methods have been developed to determine the timing and mode-switching conditions for CPS software rejuvenation (CPS SR) that will guarantee system safety. This paper presents the requirements that need to be met by the run-time system to support CPS SR. It also presents an implementation and demonstration of the run-time system for the PX4 autopilot system for autonomous vehicles.

Technique of testing cyber vulnerabilities and quality of Cyberphysical software systems

Cyber vulnerability testing and software quality cyberphysical systems (complexes) is an important task in ensuring its reliability and security. When working with several variations of products or their versions, testing all software for every variation is resource intensive and irrational. To implement effective technological and economical quality of testing and cyber vulnerabilities of cyberphysical systems software (complexes) in terms of its increasing complexity, both in time (when considering the version) and in space (when considering variation) and lack of access to program code should be developed as follows new methods. Those methods will allow to use the results of previous tests and focus on the most important, for their testing, not yet tested parts. This is possible using regression testing methods and the appropriate choice of test cases and their prioritization to identify and address software issues and cyber vulnerabilities. Of course, testing variations and versions without access to source code, is an extremely problematic and costly task. The article analyzes the stages of regression testing and proposes an improved method for selecting test cases for testing of cyber vulnerabilities of software of cyberphysical systems (complexes) without access to program code. During the study, an analysis of the achievements in this area was conducted, investigating leading experts works. This article also identifies and compares the effectiveness of prioritized and non-prioritized test cases using the average percent detection rate (APFD). As a result of the study, new metrics for measuring test coverage are presented.

Технология программной имплементации цифрового двойника в контур IoT управления HVAC-системой

The development of application software for cyber-physical systems of buildings involves the widespread use of Internet of Things (IoT) integration platforms. In practice, the flexible functionality of IoT platforms often leads to additional costs for software enhancement of existing and connection of new units, in particular digital twins. The paper proposes a technological solution for the implementation of a digital twin of the ventilation process in the IoT control loop of heating, ventilation and air conditioning (HVAC) systems for buildings and industrial facilities. The implementation and execution of the digital twin in the form of a dynamic simulation model in the object-oriented modelling language Modelica in the OpenModelica environment is considered. The IoT platform InfluxData, based on the TICK stack, is considered as an example of an integration environment. It is a horizontally-oriented IoT platform that contains the mechanism for collecting data from devices and the InfluxDB time-series database for storing metrics. To integrate simulation models on Modelica with InfluxDB, an OMPython server is proposed. In this case, the integration scripts are executed in the Python language, which as a result extends the traditional capabilities of the IoT platform significantly to the level of a digitally twinned control system. This HVAC control involves adapting control loops by taking into account the dynamics of the air distribution process over the ventilation network, evaluating and compensating for process inertia. The publication was prepared within the framework of the Academic Fund Program at the HSE University in 2020–2021 (grant № 21-04-039).

Lantern: A domain specific language for energy awareness in smart-homes

This paper argues that energy consideration should be central to software development. It speculates that including the notion of energy awareness in programming language design for domain specific languages (DSLs) is a novel way in which energy-aware and energy-efficient applications can be developed. It outlines the design criteria and rationale for using a language-focused approach for energy-awareness. It proposes Lantern, a DSL for supporting energy awareness in Cyber-Physical Systems software development. Lantern allows the development of applications that better manage and reduce the carbon footprint of devices. The design of Lantern is aimed at supporting the general development of Cyber-Physical Systems. This paper focuses on the scenario of smart homes, using statically defined locations within a specified environment.

Improvement Practices in the Performance of a CPS Multiple-Joint Robotics Simulator

In the Fourth Industrial Revolution environment, plenty of automatic and smart software in diverse fields will come out, such as virtual reality/augmented reality (VR/AR), autonomous robots and vehicles, smart factoring, and so on. In Korea, especially, one important issue is the cyber–physical system (CPS), used for monitoring and controlling the smart and automatic system in a smart city. This kind of system, therefore, needs to have good performance; otherwise, it may not respond in time. To solve this, we propose a code visualization approach to reduce code complexity based on a static analysis, which identifies bad codes against performance. To ensure better performance, we make our queries identify performance degradation factors, store statically analyzed data into database (DB) tables, and visualize bad operation patterns. For performance improvement, we can refactor with them. As a result, we reduce the code complexity of CPS-based software to obtain good performance. With this approach, we expect to have better performance and a reduction in the complexity of CPS software without even power consumption.

Software testing for cyber-physical systems suffering uncertainty

Cyber-physical systems (CPS) represent an important part of the software infrastructure in the ternary human-cyber-physical universe. In this new era, the CPS software should be continually adapting and evolving. Such constantly-growing CPS software is capable of handling emerging software environments, developing models, and executing platforms. However, environmental uncertainty poses challenges to CPS testing. In this article, the challenges of CPS testing caused by environmental uncertainty are studied. A comprehensive analysis of the impact of environmental uncertainty on CPS testing is conducted, and a research framework for effective and efficient testing CPS is proposed. Based on the proposed framework, the state-of-the-art testing CPS software is discussed, and three testing techniques that address environmental uncertainty are introduced, including a test input generation approach (SIT), a test oracle generation approach (CoMID), and an environmental suitability evaluation approach (SynEva). The experiments are conducted using an illustrative self-adaptive robot car, and the obtained experimental results show that the three proposed approaches can provide effective CPS testing.

Функционально-стоимостный анализ программного обеспечения киберфизической системы офисного здания

Функционально-стоимостный анализ программного обеспечения киберфизической системы офисного здания

Automatic Verification of Control Software in Cyber-Physical Systems with Plant Simulators

The paper describes solving the problem of automatic verification of control software in cyber-physical systems created by means of process-oriented programming. A method based on plant simulators is proposed, and its implementation on the basis of the LabVIEW package and Reflex language translator is described.

Programming support for time-sensitive adaptation in cyberphysical systems

Cyberphysical systems (CPS) integrate embedded sensors, actuators, and computing elements for controlling physical processes. Due to the intimate interactions with the surrounding environment, CPS software must continuously adapt to changing conditions. Enacting adaptation decisions is often subject to strict time requirements to ensure control stability, while CPS software must operate within the tight resource constraints that characterize CPS platforms. Developers are typically left without dedicated programming support to cope with these aspects. This results in either to neglect functional or timing issues that may potentially arise or to invest significant efforts to implement hand-crafted solutions. We provide programming constructs that allow developers to simplify the specification of adaptive processing and to rely on well-defined time semantics. Our evaluation shows that using these constructs simplifies implementations while reducing developers' effort, at the price of a modest memory and processing overhead.

A survey of language-based approaches to Cyber-Physical and embedded system development

As computers continue to advance, they are becoming more capable of sensing, interacting, and communicating with the physical and cyber world. Medical devices, electronic braking systems in automotive applications, and industrial control systems are examples of the many Cyber-Physical Systems (CPS) that utilize these computing capabilities. Given the potential consequences of software related failures in such systems, a high degree of safety, security, and reliability is often required. Programming languages are important tools used by programmers to develop CPS. They provide a programmer with the ability to transform designs into machine code. Of equal importance is their ability to detect and avoid programming mistakes. The development of CPS has predominantly been accomplished using the C programming language. Although C is a powerful language, it lacks features present in other languages that facilitate the development of reliable systems. This has prompted research into language-based alternatives for improving program quality through the use of programming languages. This paper presents an overview of the characteristics of embedded and cyber-physical systems and the associated requirements imposed on programming languages. This is followed by a survey of relevant research into language-based methods for creating safe, reliable, and robust software for CPS.

A new practice-driven approach to develop software in a cyber-physical system environment

Cyber-physical system (CPS) is an emerging area, which cannot work efficiently without proper software handling of the data and business logic. Software and middleware is the soul of the CPS. The software development of CPS is a critical issue because of its complicity in a large scale realistic system. Furthermore, object-oriented approach (OOA) is often used to develop CPS software, which needs some improvements according to the characteristics of CPS. To develop software in a CPS environment, a new systematic approach is proposed in this paper. It comes from practice, and has been evolved from software companies. It consists of (A) Requirement analysis in event-oriented way, (B) architecture design in data-oriented way, (C) detailed design and coding in object-oriented way and (D) testing in event-oriented way. It is a new approach based on OOA; the difference when compared with OOA is that the proposed approach has different emphases and measures in every stage. It is more accord with the characteristics of event-driven CPS. In CPS software development, one should focus on the events more than the functions or objects. A case study of a smart home system is designed to reveal the effectiveness of the approach. It shows that the approach is also easy to be operated in the practice owing to some simplifications. The running result illustrates the validity of this approach.

A model-based software development method for automotive cyber-physical systems

The development of automotive cyber-physical systems (CPS) software needs to consider not only functional requirements, but also non-functional requirements and the interaction with physical environment. In this paper, a model-based software development method for automotive CPS (MoBDAC) is presented. The main contributions of this paper are threefold. First, MoBDAC covers the whole development workflow of automotive CPS software from modeling and simulation to code generation. Automatic tools are used to improve the development efficiency. Second, MoBDAC extracts nonfunctional requirements and deals with them in the implementation model level and source code level, which helps to correctly manage and meet non-functional requirements. Third, MoBDAC defines three kinds of relations between uncertain physical environment events and software internal actions in automotive CPS, and uses Model Modifier to integrate the interaction with physical environment. Moreover, we illustrate the development workflow of MoBDAC by an example of a power window development.

Quantitative analysis for symbolic heap bounds of CPS software

One important quantitative property of CPS (Cyber-Physical Systems) software is its heap bound for which a precise analysis result needs to combine shape analysis and numeric reasoning. In this paper, we present a framework for statically finding symbolic heap bounds of CPS software. The basic idea is to separate numeric reasoning from shape analysis by first constructing an ASTG (Abstract State Transition Graph) and then extracting a pure numeric representation which can be analyzed for the heap bounds. A quantitative shape analysis method based on symbolic execution is defined in the framework to generate the ASTG. The numeric representation is extracted based on program slicing technique and inputted into an abstract interpretation tool for computing the heap bounds. We take list manipulating programs as an example to explain how to instantiate the framework for important data structures and to exhibit its practicability. A novel list abstraction method is also presented to support the instantiation of the framework.