Development Of Critical Systems Research Articles

A maintainable and iterative development approach of critical systems with FoCaLiZe

The life-cycle development of critical systems follows mainly a V-cycle process overlapped with proofs and/or verification techniques. At the first development stage, a critical system must be, precisely, and as completely as possible described. Thus, it is recommended to use a graphical modeling language standard such as the Unified Modeling Language (UML) and the Object Constraint Language (OCL), to which both customers and developers could contribute. Then, the graphical design with its formal specification (requirements) is mapped into a complete formal development environment, using an MDE (Model-driven engineering) approach. The formal environment has to assess the development until the generation of a secure code. In this context, we propose a life-cycle development approach that combines UML/OCL and the FoCaLiZe formal environment for the secure development of critical systems. The proposed approach ensures essential development constraints such as strict boundaries and traceability between development phases. It also ensures a secure maintenance phase using partial transformation techniques from UML/OCL to FoCaLiZe. The latter enhances the transformation from UML/OCL into FoCaLiZe to support incremental development and assist developers in correcting modeling errors. The proposed approach is mostly dedicated to secure and maintainable lifecycle development processes of critical systems. The formal environment assesses the development process until the generation of a secure code. To illustrate the proposed approach, we present the stages of development of a constrained system controlling military objects. The development of this system uses the iterative, incremental, and maintainability stages as described by the development approach, until the generation of secure code.

An Integrated Mutation Analysis Tool (Imat) For Simulink Models and Their Ideal Implementation

Mutation analysis is proving to be an effective approach in detecting the design flaws for safety system designs such as flight control systems or the stall warning systems. The drawback of these analyses is that they are time-consuming and difficult-to-use. This paper discusses about the mutation tool, IMAT, developed in-house for detecting the design flaws of safety critical systems designed in SIMULINK. The IMAT tool is developed as a plug-in to the SIMULINK tool suite and enhances the performance of the model-based development of safety critical systems. Some of the unique features of the tool are ease-of-use, portable, scalable, userfriendly and easy to analyse the reports.

Hardware/Software Co-Assurance for the Rust Programming Language Applied to Zero Trust Architecture Development

Zero Trust Architecture requirements are of increasing importance in critical systems development. Zero trust tenets hold that no implicit trust be granted to assets based on their physical or network location. Zero Trust development focuses on authentication, authorization, and shrinking implicit trust zones to the most granular level possible, while maintaining availability and minimizing authentication latency. Performant, high-assurance cryptographic primitives are thus central to successfully realizing a Zero Trust Architecture. The Rust programming language has garnered significant interest and use as a modern, type-safe, memory-safe, and potentially formally analyzable programming language. Our interest in Rust particularly stems from its potential as a hardware/software co-assurance language for developing Zero Trust Architectures. We describe a novel environment enabling Rust to be used as a High-Level Synthesis (HLS) language, suitable for secure and performant Zero Trust application development. Many incumbent HLS languages are a subset of C, and inherit many of the well-known security shortcomings of that language. A Rust-based HLS brings a single modern, type-safe, memory-safe, high-assurance development language for both hardware and software. To study the benefits of this approach, we crafted a Rust HLS subset, and developed a frontend to the hardware/software co-assurance toolchain due to Russinoff and colleagues at Arm, used primarily for floating-point hardware formal verification. This allows us to leverage a number of existing hardware/software co-assurance tools with a minimum investment of time and effort. In this paper, we describe our Rust subset, detail our prototype toolchain, and describe the implementation, performance analysis, formal verification and validation of representative Zero Trust algorithms and data structures written in Rust, emphasizing cryptographic primitives and common data structures.

Fragility-based system performance assessment of critical power infrastructure

Climate change and population growth require the development and operations of critical power infrastructure systems to meet the energy demand. Performance assessment of the power infrastructure usually focuses primarily on the thermodynamic analysis calculating the energy output and system efficiency. However, the energy output from the thermodynamic analysis under normal operation could not fully represent the infrastructure behavior due to the neglect of the component reliability in the energy generation system. There is a lack of consideration of the energy delivery system and its fragility with respect to external meteorological parameters (e.g., wind). In this study, the fragility of the energy-delivery system concerning wind speed is modeled and integrated to assess critical power infrastructure performance. The reliability consideration of the energy generation system is included based on the state space diagram and the frequency-balance method. The fragility of the energy-delivery system is used to derive a system reliability index for the system which is the probability that end-users will receive the energy. Besides, sensitivity analysis is conducted to investigate the influence of the important decision variables on the system performance. The study employs a small-scale power infrastructure system at the University of Connecticut as an example to demonstrate the feasibility of the performance assessment framework. The system is composed of a cogeneration plant and energy distribution systems. The results from the case study prove that the decision variables have considerable nonlinear impacts on the system performance. With the integration of fragility, the proposed approach could estimate the energy received by consumers from the generation site.

Critical Systems Thinking

This chapter describes the development of critical systems thinking, its basic themes, and a practical application that had an effect on the lives of millions of people. The chapter presents the way critical systems thinking emerged, as well as an account of some of the important contributions that it produced in the last decades. Its two key cornerstones are discussed: the emancipatory-oriented strand and the pluralism-oriented strand. Subsequently, the basic themes or commitments of this field are presented, and an instance of a real life implementation that involved the participation of a wide variety of stakeholders and communities. This application illustrates some of the main themes and principles of critical systems thinking, as well as the significant impact it can have in the wellbeing of societies and organisations. Finally, some future potential developments of critical systems thinking are presented, showing its dynamism and capacity to transform the systems approach theory and practice.

Modeling and Analysis of Probabilistic Real-time Systems through Integrating Event-B and Probabilistic Model Checking

Event-B is a formal method used in the development of safety critical systems. However, these systems may introduce uncertainty, and need also to meet real-time requirements, which make their modeling and analysis a challenging task. Existing works on extending Event-B with probability and time did not address both probability and time in a single framework. Besides, they did focus the most on extending the language itself, not on integrating the extended Event-B with verification. In this paper, we aim to represent both probability and time in the Event-B language, and we will show how such a representation can be automatically translated into Probabilistic Timed Automata (PTA) described in the language of the probabilistic model checker PRISM. This translation would allow us to analyze probabilistic, as well as time-bounded probabilistic reachability properties of probabilistic real-time systems through the Probabilistic Timed CTL (PTCTL) logic.

An analytical code quality methodology using Latent Dirichlet Allocation and Convolutional Neural Networks

Recently, Code Quality (CQ) has become critical in a wide range of organizations and in many areas from academia to industry. CQ, in terms of readability, security, and testability, is a major goal throughout the software development process because it affects overall Software Quality (SQ) in terms of subsequent releases, maintenance, and updates. It is particularly important for the development of safety critical systems. Existing studies on CQ have several shortcomings in that they are based on incomplete information about the source code, and tend to focus on only one feature, which is likely to determine the performance of the model. Moreover, these considerations often limit obtaining high accuracy because there is no strong relationship between the input data and the output data. Thus, it is necessary to design an effective and efficient SQ measurement system for measuring multiple quality factors. To that end, we propose a deep learning framework that employed a Latent Dirichlet Allocation (LDA) with Convolutional Neural Networks (CNN), called CNN-LDA, to classify input data into topics that are related to CQ features and to identify hidden patterns and correlations in programming data. Three SQ metrics (i.e., readability, security, and testability) and machine learning techniques (e.g., random forest (RF) and support vector machine (SVM)) are taken into account to validate the proposed model. The proposed CNN-LDA outperformed its peers across the vast majority of datasets examined. The average overall F-measure for readability, security, and testability are 94%,94% and 93%. The average overall accuracy for readability, security, and testability are 93%,93% and 92%. The superiority of LDA-CNN over the other classifiers was very clear based on a Wilcoxon’s non-parametric statistical test (α=0.05).

A Survey of Real-Time Ethernet Modeling and Design Methodologies: From AVB to TSN

With the development of real-time critical systems, the ever-increasing communication data traffic puts forward high-bandwidth and low-delay requirements for communication networks. Therefore, various real-time Ethernet protocols have been proposed, but these protocols are not compatible with each other. The IEEE 802.1 Working Group developed standardized protocols named Audio Video Bridging (AVB) in 2005, and renamed it Time-Sensitive Networking (TSN) later. TSN not only adds new features but also retains the original functions of AVB. Proposing real-time Ethernet modeling and design methodologies is the key to meeting high-bandwidth and low-delay communication requirements. This article surveys the modeling from AVB to TSN, mainly including: (1) AVB and TSN modeling; (2) end-to-end delay modeling; (3) real-time scheduling modeling; (4) reliability modeling; and (5) security modeling. Based on these models, this article surveys the recent advances in real-time Ethernet design methodologies from AVB to TSN: (1) end-to-end delay analysis from AVB to TSN; (2) real-time scheduling from AVB to TSN; (3) reliability-aware design for TSN; and (4) security-aware design for TSN. Among the above four points, the last two points are only for TSN, because AVB lacks reliability and security mechanisms. This article further takes the automotive use case as an example to discuss the application of TSN in automobiles. Finally, this article discusses the future trends of TSN. By surveying the recent advances and future trends, we hope to provide references for researchers interested in real-time Ethernet modeling and design methodologies for AVB and TSN.

THE RESEARCH OF LEVELS OF DESCRIPTION OF MODERN CRITICAL APPLICATION SYSTEMS

At the current stage of economic and technical development, one of the most important problems is maintaining the reliability and fault tolerance of critical application systems used in the management of nuclear power plants, air, rail and road transport, technological units in metallurgy, the oil and gas industry, etc. The general trend of the development of critical application systems is characterized by the following factors: an increase in the degree of complexity of control objects, an expansion of the composition and level of complexity of solved functional tasks, a reduction in decision-making time, an increase in the cost of errors and the probability of large-scale emergency situations. The main reasons for the escalation of dangerous situations are failures in critical application systems. The publication examines the concept of a critical application system, examines the question of levels of description of critical application systems, examines the issue of interdependent subsystems based on the concept of potential and information technologies supporting the reliability and fault tolerance of critical application systems. For such systems (power supply and energy supply systems, water supply and drainage, etc.), an urgent problem is to ensure the objectivity, reliability and adequacy of forecasting and prevention of dangerous and possible cascading effects that can lead to man-made accidents and catastrophes. This can significantly affect the functioning, stability and survivability of systems of critical application, the ecological and technogenic safety of the surrounding territories, and the safety of life of the population of Ukraine. In the event of damage to the system of critical application, which can be sudden and intense, it will lead to an emergency situation of a man-made nature.

Qualitative and quantitative analysis of the reliability of NPC and ANPC power converters for aeronautical applications

In more electrical aircraft, most flight control wing surface actuators are either electro-hydrostatic or electro-mechanical, whether in manual or autopilot mode. Their reliability is essential for flight safety; failure of even one actuator can have catastrophic consequences. According to ARP4761 guidelines for the development and certification of critical aircraft systems, the probability of failure of flight-control actuator components must be less than 10-9 per hour of flight. In this paper, we compare the probability of failure per hour (PFH) of conventional two-level power converters and three-level NPC and ANPC converter topologies designed in our laboratory. In accordance with ARP procedures, PFH was calculated using an approach that includes qualitative analysis based on failure mode and effect analysis (FMEA) methodology as well as quantitative analysis based on truth tables. ANPC converter met all the requirements of the functional hazard assessment in all cases of defects. Finally, we discuss factors that determine the feasibility of implementing power converters in flight control systems.

Resilience in Global Value Chains: A Systemic Risk Approach

Global value chains (GVCs) have increased efficiencies, accelerated production, reduced costs, and increased wealth and opportunities for workers, firms, nations, and the global economy as a whole. However, the benefits and efficiencies provided by these GVCs come at the cost of increasing risks. This is largely because the emergence and evolution of GVCs have been enabled by advancements in globalization, complexity, and technology, as well as the development of critical global systems that underpin these industries—such as communication, transportation, financial systems, and others. GVCs are thus only as stable as these underlying global systems upon which they depend, and are vulnerable to potential shocks to these systems. The COVID-19 pandemic and other recent global interruptions in GVCs have demonstrated the importance of applying a systems theory approach, which allows us to identify—and eventually begin managing for—the multidimensional risks that these global industries face. Studying the stability and reliability of these global industries requires not only an understanding of risks within just the GVCs but also an awareness of vulnerabilities in numerous critical underlying systems that form the infrastructure of GVCs and the global economy. As examples, we examine six such underlying systems: health care and public health, supply chain and logistics, technology and cyber, finance, sociopolitical, and the environment. Each of these examples illustrates that disruptions, fragilities, or failures in critical underlying systems can dramatically impact GVCs as a whole and make the geographic regions in which these systems are vulnerable less attractive to industry investment and expansion. Introducing methodologies and concepts from systems theory, we illustrate that these underlying global systems that expose GVCs to vulnerabilities are complex adaptive systems (CAS). As systems of systems composed of CAS, these GVCs consequently also can be modeled as CAS. We argue that not only does this CAS perspective help to mitigate the multilayered GVC risks through better understanding and the application of CAS tools like “adaptive management,” but it also empowers policymakers to better attract GVCs to their borders by prioritizing the creation of more resilient underlying systems.

A formal approach to rigorous development of critical systems

AbstractSafety critical systems, such as medical, automotive, and avionics systems, play an important role in our daily lives. Increasing demand for new technologies in these safety critical systems requires rapid adoption of commercial hardware and software. However, the adoption of new hardware and software increases life‐threatening vulnerabilities. To aid in the reduction of these vulnerabilities and system failures, this paper proposes a framework based on formal methods for developing safety‐critical systems from requirements analysis to code generation. This framework includes a development process for documenting system requirements using tabular expressions, automatic formal model generation from the documented requirements, verification and validation of the generated formal models using proof techniques and animations, interactive simulation for validating the required behavior of the developed models by enabling domain experts to observe the system states according to, and finally, code generation from the formal model into a desired language. A prototype toolchain is developed to automate this framework. An assessment of the proposed framework is undertaken through a case study: insulin infusion pump (IIP).

WITHDRAWN: Critical review on software reliability models: Importance and application of reliability analysis in software development

Abstract Initially the term reliability was used in the development of critical systems (controller of the nuclear plant, navigational system of the spacecraft, customer accounting system in a bank and stock-trading system… etc…). Later, it had been used in the small scale system and application development, due to the impact of it in the quality measurement and enhancement the of software system. In the software development, the word reliability means the failure free operation of the software system in a pre-specified time and environment. Reliability is the important metric which reflect the degree of correctness of the program. Reliability prediction in the early phase of the development process offers many advances like quality enhancement, resource allocation for development and testing and confidence about the software quality. Many programming languages (C++, Java, .NET… etc…) had developed based on this feature. Nowadays the complexity of software design and its size is augmented as the need of the societies increased. For this reason, software development process also moved towards the component based development and other advanced process for the development, which enable the superior reuse and easy maintenance and quick development of the software system. There is a need for the new models which would be developed based on the new development process. Because, all the existing models having assumptions and limitation which can only be suitable for the specific project or process. The main objective of this paper is to give the idea and knowledge to the young researchers, about the software reliability models of different development processes and its importance to produce the failure free software product. And also stimulate them to develop the novel models which can be used in the new software development process and projects.

Semantic Recovery of Traceability Links between System Artifacts

This paper introduces a mechanism to recover traceability links between the requirements and logical models in the context of critical systems development. Currently, lifecycle processes are covered by a good number of tools that are used to generate different types of artifacts. One of the cornerstone capabilities in the development of critical systems lies in the possibility of automatically recovery traceability links between system artifacts generated in different lifecycle stages. To do so, it is necessary to establish to what extent two or more of these work products are similar, dependent or should be explicitly linked together. However, the different types of artifacts and their internal representation depict a major challenge to unify how system artifacts are represented and, then, linked together. That is why, in this work, a concept-based representation is introduced to provide a semantic and unified description of any system artifact. Furthermore, a traceability function is defined and implemented to exploit this new semantic representation and to support the recovery of traceability links between different types of system artifacts. In order to evaluate the traceability function, a case study in the railway domain is conducted to compare the precision and recall of recovery traceability links between text-based requirements and logical model elements. As the main outcome of this work, the use of a concept-based paradigm to represent that system artifacts are demonstrated as a building block to automatically recover traceability links within the development lifecycle of critical systems.

The CLEARSY safety platform: 5 years of research, development and deployment

• Smart combination of B formal method and diverse electronics. • Safety critical systems do not require high profiles anymore. • Connection with DSLs to seamlessly integrate existing development cycle. • Connection with proved system-level model, to derive software specification. The CLEARSY Safety Platform (CSSP) was designed to ease the development of safety critical systems and to reduce the overall costs (development, deployment, and certification) under the pressure of the worldwide market. A smart combination of hardware features (double processor) and formal method (B method and code generators) was used to produce a SIL4-ready platform where safety principles are built-in and cannot be altered by the developer. Summarizing a 5-year return of experience in the effective application in the railways, this article explains how this approach is a game-changer and tries to anticipate the future of this platform for safety critical systems. In particular, the education of future engineers and the seamless integration in existing engineering processes with the support of Domain Specific Languages are key topics for a successful deployment in other domains. DSL like Robosim to program mobile robots and relay circuits to design railway signaling systems are connected to the platform.

Guiding assurance of architectural design patterns for critical applications

Abstract Development of critical systems nowadays is hardly achievable without reuse of previous knowledge. Design patterns have an important role in the design of such systems as they define and document common solutions to recurring design problems. However, critical systems such as those that are safety or security related, often require specific assurances that the system is adequate to operate in a given environment. Just as with any other reused knowledge in such systems, the reuse via application of design patterns needs to be assured every time. In this paper, we present a methodology for assuring the application of design patterns in critical domains. In particular, we enrich the design patterns template to support their further assurance. We define the aspects that should be tackled during the assurance of a design pattern application. We use the information specified in the design pattern template to guide the automated instantiation of the argumentation for each design pattern application in the system. We provide tool-support for our methodology in the context of the AMASS tool-platform and evaluate it in an automotive case study.

Integration validation of key components for small sounding rockets

To develop sounding rockets that can be used for various missions, a university, research center, and two enterprises collaborated to conduct a critical-system development project on a small-scale sounding rocket. The Korea Advanced Institute of Science and Technology (KAIST) Rocket Laboratory and Space Solution Co., Ltd. collaborated to develop a hybrid rocket and a propellant-feeding system using hydrogen peroxide as an oxidizer. The KAIST Satellite Technology Research Center has developed a non-pyrotechnic recovery system, and Naraspace Technology Co., Ltd. has developed rocket avionics. Using a 2.39-m technology demonstrator that weighs 16.4 kg, the developed system has been validated at low altitudes, and the applicability of the small-scale sounding rocket has been evaluated. The combustion stability, short ignition delay, and high performance of the H2O2 hybrid rocket were confirmed through static firing and flight tests. The reliability and capacity of the non-pyrotechnic recovery system (which uses a spring) were confirmed by ground and flight tests. Perfect operation of the developed rocket avionics, such as control of the main oxidizer valve and recovery system, emergency functions, data transmission, and data storage was confirmed through ground and flight tests.

Model-driven Design-Runtime Interaction in Safety Critical System Development: an Experience Report.

Automotive, aerospace, industrial control, and railway systems are examples of application domains which are particularly characterized by the need for developing and managing critical systems. Model-driven engineering is recognized as an effective solution to leverage abstraction and automation while developing complex systems. One of the major and key challenges in the model-driven engineering of critical software systems is the integration of design and runtime aspects. Even though several methods and tools are available for performing measurements of runtime properties, the ability to trace them with design models is still limited. In the context of a real railway system, this paper presents a model-based approach that has been conceived to analyze runtime data (coming from different sensors), to produce corresponding traceability models and to automatically infer from them potential design issues that might need to be fixed in order to solve detected system malfunctionings.

An extensible collaborative framework for monitoring software quality in critical systems

ContextCurrent practices on software quality monitoring for critical software systems development rely on the manual integration of the information provided by a number of independent commercial tools for code analysis; some external tools for code analysis are mandatory in some critical software projects that must comply with specific norms. However, there are no approaches to providing an integrated view over the analysis results of independent external tools into a unified software quality framework. ObjectiveThis paper presents the design and development of ESQUF (Enhanced Software Quality Monitoring Framework) suitable for critical software systems. It provides the above enriched quality results presentation derived not only from multiple external tools but from the local analysis functions of the framework. MethodAn analysis of the norms and standards that apply to critical software systems is provided. The detailed and modular design of ESQUF adjusts to the integration requirements for external tools. UML is used for designing the framework, and Java is used to provide the detailed design. The framework is validated with a prototype implementation that integrates two different external tools and their respective quality results over a real software project source code. ResultsThe integration of results files and data from external tools as well as from internal analysis functions is enabled. The analysis of critical software projects is made posible yielding a collaborative space where verification engineers share information about code analysis activities of specific projects; and single presentation space with rich static and dynamic analysis information of software projects that comply with the required development norms.

Nutrition and Fetal Origins of Diseases in Adults

Accumulating evidence suggests that the early-life environment has lasting effects on health and disease into adulthood. The current concept of developmental origins of adulthood disease has expanded beyond the original observation by Barker and colleagues correlating low birth weight with adulthood cardiovascular and metabolic disorders. Notably, the fetal-neonatal nutritional environment has a significant role in influencing an individual’s wellness in adulthood. During critical periods of fetal and neonatal development, tissues and organ systems are most vulnerable to nutrient deficiencies. Through fetal programming mechanisms such as epigenetic modification, a biochemical process that regulates gene expression without altering the genetic code, developing tissues adapt to nutrient-poor environments to preserve normal development of critical organ systems, including the brain. However, these programmed adaptations can have negative long-term health consequences if the postnatal environment does not match the fetal-neonatal environment in which the programming occurred. These long-term adverse health outcomes constitute the true cost to society, in both increased medical costs and the indirect cost of lost productivity. Here we review the effects of nutrient deficiencies on fetal programming and subsequent health outcomes, as well as the potential mechanisms that underlie fetal programming. This review contains 3 Figures, 2 Tables and 115 references Key words: critical period, epigenetics, fetal programming, iron, long-chain polyunsaturated fatty acids, neurodevelopment, nutrient deficiency, protein-energy, vitamins, zinc