SysML Models Research Articles

A reference architecture for the American Multi-Modal Energy System enterprise

The American Multimodal Energy System (AMES) is a system-of-systems comprised of four separate but interdependent infrastructure enterprises: the electric grid, the natural gas enterprise, the oil enterprise, and the coal enterprise. Their interdependence creates the need to better understand the underlying architecture in order to move towards a more sustainable, resilient and accessible energy system. Collectively, these requirements necessitate a sustainable energy transition that constitute a change in the AMES instantiated architecture; although it leaves its reference architecture largely unchanged. Consequently, from a model-based systems engineering perspective, identifying the underlying enterprise model’s reference architecture becomes a high priority. This paper defines a reference architecture for the AMES and its four component energy enterprises in a single SysML model. The architecture includes (allocated) block definition and activity diagrams for each enterprise. The reference architecture was developed from the S&P Global Platts (GIS) Map Data Pro data set and the EIA Annual Energy Outlook dataset. This reference architecture serves as the foundation from which to accurately and consistently create mathematical and informatic digital twins of the AMES.

Research on visual simulation for complex weapon equipment interoperability based on MBSE

AbstractAs military reforms continue to develop, the battlefield environment is becoming increasingly complex, and traditional single-service combat methods have evolved into integrated joint and collaborative information operations that break down service boundaries on land, sea, and air. The level of weapon system confrontation has also evolved into a system-to-system confrontation. Traditional document-based system architecture design methods can no longer address the complexity and emergent challenges of weapon system construction. In this paper, based on model-driven system engineering, an open, integrated, model-driven weapon equipment interaction system that supports human interaction was constructed using the SysML modeling language and Magicdraw modeling tool. The Unreal Engine 4 landscape building function was used to construct a virtual battlefield environment, and a communication server was developed using C# language to perform visual simulation of interoperability between weapon systems. Based on model-driven weapon equipment interoperability, visual simulation is used to ensure that the function of the weapon equipment system meets the requirements of combat and the combat effectiveness of the system is maximized.

Orion SysML Model, Digital Twin, and Lessons Learned for Artemis I

AbstractIn 2015 it was recognized by NASA's Orion Chief Engineer that NASA's design insight into the Orion subsystems for Artemis I was not sufficient to provide standard engineering support to flight operations. To address these concerns, provide an opportunity to apply emerging model‐based systems engineering and digital twin methodologies, and provide opportunities for employees across NASA to get hands‐on training, an Orion Digital Twin pilot project was initiated in 2020 as part of the Agency's Digital Transformation initiative. With the increase in complexities of spacecraft, and decreased time to made decisions during missions in critical or emergency situations, digital modeling and integration of design can reduce the time to answer questions by days and the required human resources by an order of magnitude over conventional approaches and was identified to be a critical capability for NASA's future. This paper describes the genesis of the Orion Digital Twin pilot project, efforts undertaken, a reproducible methodology to take available system information from a mature program to create an executable SysML model that supports a link to the physical asset, and associated lessons learned and project deliverables.

Linking UAF and SysML Models: Achieving Alignment between Enterprise and System Architectures

AbstractThe Unified Architecture Framework (UAF) is designed to facilitate the modeling of a system (at a high level) along with the driving enterprise objectives and strategies, operational activities and mission threads, capability objectives and roadmaps, and a variety of other considerations that apply to the system under development. However, when the system (or a collection of systems) is modeled using UAFML, there is a challenge in linking the UAF model to the corresponding system models created using SysML to ensure proper alignment is established and maintained between the Enterprise and System levels. This paper examines four alternative ways of achieving this alignment and discusses the benefits and drawbacks of each approach.

Pragmatic verification and validation of industrial executable SysML models

AbstractIn recent years, Model‐Based Systems Engineering (MBSE) practices have been applied in various industries to design, simulate and verify complex systems. The verification and validation (V&V) of such systems engineering models are crucial to develop high‐quality systems. However, this is a challenging problem due to the complexity of the models and semantic differences in how different tools interpret the models, which can undermine the validity of the obtained results if they go undiscovered. To address these issues, we propose (i) a subset of the SysML language for which the practical semantic integrity of tools can be achieved and (ii) a cloud‐based V&V framework for this subset, lifting verification to an industrial scale. We demonstrate the feasibility of our approach on an industrial‐scale model from the aerospace domain and summarize the lessons learned during transitioning formal verification tools to an industrial context.

A Case in Point: Verification and Testing of a EULYNX Interface

We present a case study on the application of formal methods in the railway domain. The case study is part of the FormaSig project, which aims to support the development of EULYNX — a European standard defining generic interfaces for railway equipment — using formal methods. We translate the semi-formal SysML models created within EULYNX to formal mCRL2 models. By adopting a model-centric approach in which a formal model is used both for analyzing the quality of the EULYNX specification and for automated compliance testing, a high degree of traceability is achieved. The target of our case study is the EULYNX Point subsystem interface. We present a detailed catalog of the safety requirements, and provide counterexamples that show that some of them do not hold without specific fairness assumptions. We also use the mCRL2 model to generate both random and guided tests, which we apply to a third-party software simulator. We share metrics on the coverage and execution time of the tests, which show that guided testing outperforms random testing. The test results indicate several discrepancies between the model and the simulator. One of these discrepancies is caused by a fault in the simulator, the others are caused by false positives, i.e. an over-approximation of fail verdicts by our test setup.

Verification and Validation of SysML Models

ABSTRACTModel‐based systems engineering depends on correct models. However, thus far, relatively little attention has been paid to ensuring their correctness. This paper describes a methodology for performing verification and validation on models written in SysML. The methodology relies on a catalog of candidate requirements that can be tailored for a specific project. Both manual and automated methods are used to verify and validate these requirements. Manual methods are necessary where knowledge of the domain and other extrinsic characteristics are necessary. Automated methods can be used where the requirements cover the use of SysML. Examples from a public domain SysML model of a satellite are presented to demonstrate application of automated requirements verification.

Design of Cyber Bio-analytical Physical Systems: Formal methods, architectures, and multi-system interaction strategies

Integration of the Cyber–Physical System (CPS) concept with bio-analytical devices is highly desirable to enable device automation as well as to improve diagnostic and analytical capabilities. However, the modeling must account for entity interactions, system dynamics, and non-functional aspects required for proper device functionality.This paper presents a model-based system architecture that builds upon an extended timed automata-based formal technique. In contrast to prior works that utilized SysML or UML-based models, this allows for the wireless control of bio-analytical instruments. Using this formal method, the UPPAAL tool is used to model and test a case study called “A droplet flow cytometer for testing bacteria’s susceptibility to antibiotics”. The study shows the implications of formal techniques for the design and verification of wireless automation of high-throughput laboratory setups in Model-Based System Engineering (MBSE). Moreover, the paper extends the above aspects by adding the possibility to model multi-system interaction. This is used to analyze the trade-off between centralized and decentralized information flow strategies for better system performance under delay and bandwidth constraints. UPPAAL Stratego is used to analyze strategies for achieving specific delays and bandwidth consumption while avoiding packet losses in the event of network congestion. The results show that under strict delay constraints and high traffic, the use-case system selects the decentralized strategy over the centralized strategy. In low-traffic scenarios, the centralized strategy is more effective at ensuring the reliable operation of systems.

Execution trace analysis for a precise understanding of latency violations

Despite the amount of proposed works for the verification of embedded systems, understanding the root cause of violations of requirements in simulation or execution traces is still an open issue, especially when dealing with temporal properties such as latencies. Is the violation due to an unfavorable real-time scheduling, to contentions on buses, to the characteristics of functional algorithms or hardware components? The paper introduces the Precise Latency ANalysis approach (PLAN), a new trace analysis technique whose objective is to classify execution transactions according to their impact on latency. To do so, we rely first on a model transformation that builds up a dependency graph from an allocation model, thus including hardware and software aspects of a system model. Then, from this graph and an execution trace, our analysis can highlight how software or hardware elements contributed to the latency violation. The paper first formalizes the problem before applying our approach to simulation traces of SysML models. A case study defined in the AQUAS European project illustrates the relevance of our approach. Last, a performance evaluation gives computation times for several models and requirements.

Bridging the Gap between SysML and OPC UA Information Models for Industry 4.0.

Bridging the Gap between SysML and OPC UA Information Models for Industry 4.0.

Situation-Aware IoT Data Generation towards Performance Evaluation of IoT Middleware Platforms.

With the increasing growth of IoT applications in various sectors (e.g., manufacturing, healthcare, etc.), we are witnessing a rising demand of IoT middleware platform that host such IoT applications. Hence, there arises a need for new methods to assess the performance of IoT middleware platforms hosting IoT applications. While there are well established methods for performance analysis and testing of databases, and some for the Big data domain, such methods are still lacking support for IoT due to the complexity, heterogeneity of IoT application and their data. To overcome these limitations, in this paper, we present a novel situation-aware IoT data generation framework, namely, SA-IoTDG. Given a majority of IoT applications are event or situation driven, we leverage a situation-based approach in SA-IoTDG for generating situation-specific data relevant to the requirements of the IoT applications. SA-IoTDG includes a situation description system, a SySML model to capture IoT application requirements and a novel Markov chain-based approach that supports transition of IoT data generation based on the corresponding situations. The proposed framework will be beneficial for both researchers and IoT application developers to generate IoT data for their application and enable them to perform initial testing before the actual deployment. We demonstrate the proposed framework using a real-world example from IoT traffic monitoring. We conduct experimental evaluations to validate the ability of SA-IoTDG to generate IoT data similar to real-world data as well as enable conducting performance evaluations of IoT applications deployed on different IoT middleware platforms using the generated data. Experimental results present some promising outcomes that validate the efficacy of SA-IoTDG. Learning and lessons learnt from the results of experiments conclude the paper.

Synchronous Integration Method of System and Simulation Models for Mechatronic Systems Based on SysML

System architecture could be described clearly and unambiguously by a descriptive system model during the system-level design of mechatronic products. However, for system verification, it is necessary to integrate the system modeling tools and simulation tools for analysis. Most of the existing integration methods focus on the integration in the physical architecture phase of the system model. A model integration framework that can integrate simulation into the logical architecture phase of the entire model for synchronous model verification is proposed in this paper. In the integration process, a Model-to-Text method is employed for information extraction and model transformation from the SysML model to the simulation model. The system model can be transformed by reusing and updating the generated simulation model through the framework for model verification. A framework with the Simulink model as the transformation target is constructed as an example in this paper, and the capability of this framework is verified by a design process of a quadruped robot. The result shows that this framework can realize the system design paradigm of integrating system verification for the entire logical architecture, which can improve the design efficiency and provide a reference for other system design and integration work.

A Web-Based Collaborative Method for SysML Modeling

Abstract Model-based systems engineering (MBSE) with SysML has become one of the best solutions to the system design of complex systems, which usually requires the collaboration of different disciplines. Web-based collaborative modeling method looks like a prioritized option because of its advantages such as “light” client, convenient maintenance, and high model reliability. In this study, we propose a web-based collaborative SysML modeling method for MBSE. First, the architectures of asynchronous and synchronous collaboration are given. Then, some key technologies for both collaborative modes are discussed. Finally, a case study is given to demonstrate the effectiveness of the proposed method.

Simulating hybrid SysML models: a model transformation approach under the DEVS framework

Simulating hybrid SysML models: a model transformation approach under the DEVS framework

Virtual testing of multifunctional moveable actuation systems

This work presents the current state of the virtual testing activities performed within the Virtual Product House (VPH) start-up project. In this project a multidisciplinary, collaborative end-to-end process for virtual product design is developed. On the basis of preliminary design and concept studies on aircraft level, the process focusses on design, manufacturing and testing of aircraft systems and structural components with special attention to certification aspects. The initial use case considers the trailing edge flap of a long-range aircraft and its actuation system. Design and analysis tools are integrated in a remote workflow execution environment to automatically generate designs and evaluate them by virtual test means. Virtual tests facilitate knowledge on properties and behavior of the virtual product in early development phases and allow to optimize design flaws in consecutive design iterations to hence reduce the risk of costly corrections later in the development process. The testing is setup in multiple stages. Currently, domain-specific tests are carried out for the moveable structure and its actuation system, with the latter being in focus for the current text. These tests address the functional verification of the actuation system in nominal and failure cases. A SysML model comprising system requirements and architecture is used to model test cases and trace test results. On the basis of these test cases, simulation configurations for virtual tests are automatically built, executed and evaluated. With this method, a continuous evaluation of designs in terms of functional verification of the moveable actuation system is possible. Moreover, the automated execution of all steps allows to determine the effects of design changes quickly without a large amount of labor-intensive and error-prone work.

A resilience systemic model for assessing critical supply chain disruptions

AbstractAssessing the impact of natural disasters and manmade incidents against critical infrastructure systems is important and challenging. As critical infrastructure sectors become more interdependent, a method is needed to assess how disruptions to one sector affect other sectors. This need is particularly significant in the case of critical national supply chains which have not received the same attention as other critical infrastructure systems. This research develops a methodology for performing supply chain impact assessments by integrating model‐based systems engineering (MBSE) with discrete event simulation (DES). SysML models capture the supply chain structure and critical infrastructure interdependencies. Simulation of the supply chain model subjected to external constraints identifies the impacts from critical infrastructure disruptions. This approach enables researchers and public policy planners to assess critical supply chain risks associated with current infrastructure implementations, and to conduct what‐if analyses on alternative solutions. Application of this methodology to assess the natural disaster impacts on an urban food supply system demonstrates the effectiveness of modeling and simulation for evaluating the impacts of critical infrastructure disruptions on a wide range of critical supply chains. Future research should apply this methodology to different national supply chains and investigate additional critical infrastructure interdependency linkage mechanisms.

Converting natural language policy article into MBSE model

AbstractSystem Engineers work on designing human interfaces for easy access to governance and technology. As we move to digital engineering, the policy documents are still written in natural language that sometimes is obscure and verbose. One way of digitizing is to convert natural language policies into machine readable system engineering models. In the past, converting natural language written policy documents into machine readable models involves great human effort and expert knowledge in relevant domains, which is a time consuming, tedious, and sometimes impossible task. Artificial Intelligence and its application have shown the potential to accelerate the process. In this study, we proposed a natural language processing (NLP)‐based framework for information extraction under the general condition that can automatically detect the actors and their responsible actions. To validate the performance of the model developed, we compared the NLP generated report with manually created SysML model. The result shows that the precision and recall rate of extracting roles and responsibility is ~0.86 and ~0.66, respectively, representing that this text‐to‐model framework has the potential to accurately convert general policy documents into SysML.

The Power of Connection between Systems Engineering and 3D Wire Harness: Model‐Based Wire Harness Engineering at Lockheed Martin Skunk Works

AbstractLockheed Martin Skunk Works has extended their digital engineering approach for wire harness engineering to span system architecture, logical design, 3D design and manufacturing representation. Their Model‐Based Wire Harness Engineering realizes the promise of Model‐Based Systems Engineering through significant improvements in integrating SysML models and 3D designs.

SysML modeling of service-oriented system-of-systems

The success of the ongoing fourth industrial revolution largely depends on our ways to cope with the novel design challenges arising from a combination of an enormous increase in process and product complexity, as well as the expected autonomy and self-organization of complex and diverse industrial hardware–software installments, often called systems-of-systems. In this paper, we employ the service-oriented architectural paradigm, as materialized in the Eclipse Arrowhead framework, to represent modern systems engineering principles and their open structural principles and, thus, relevance to flexible and adaptive systems. As for adequately capturing the structural aspect, we propose using model-based engineering techniques and, in particular, a SysML-based specialization of systems modeling. The approach is illustrated by a real-life use-case in industrial automation.

A Modelling Method for Describing and Facilitating the Reuse of SysML Models during Design Process

AbstractMBSE and SysML are increasingly finding their applications in industry as well as in academia. The reuse of the information described in SysML models depends, among others, on the modelling methods, management of dependencies between elements and on the needed remodelling effort. In this paper, a modelling method is presented that address the reuse of SysML models and descriptions as well as reuse of model variants in SysML. A case example is presented to explain the modelling methods and the gained experience is summarised in the form of general recommendations for further use.