Browsing by Author "Salado, Alejandro"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Conjoining Wymore’s Systems Theoretic Framework and the DEVS Modeling Formalism: Toward Scientific Foundations for MBSE
    Wach, Paul; Zeigler, Bernard P.; Salado, Alejandro (MDPI, 2021-05-27)
    The objective of this research article is to re-introduce some of the concepts provided by A. Wayne Wymore in his mathematical theory of Model-Based Systems Engineering, discuss why his framework might have not been adopted, and define a potential path to modernize the framework for practical application in the digital age. The dense mathematical theory has never been converted to a practical form. We propose a path to modernization by creating a metamodel of Wymore’s mathematical theory of MBSE. This enables explaining the concepts in simple to understand terms and shows the internal consistency provided by the theory. Furthermore, the metamodel allows for conversion of the theory into software application, for which we show some initial results that open the research to the art of the possible. In recognition of limitation of the theory, we make the case for a merger of the theoretical framework with the enhanced formalism of Discrete Event System Specification (DEVS). This will establish a path toward the scientific foundations for MBSE to enable future implementations of the complementary pairing and their empirical results.
  • Thumbnail Image
    Coordination of verification activities with incentives: a two-firm model
    Kulkarni, Aditya U.; Wernz, Christian; Salado, Alejandro (2020-11-12)
    In systems engineering, verification activities evaluate the extent to which a system under development satisfies its requirements. In large systems engineering projects, multiple firms are involved in the system development, and hence verification activities must be coordinated. Self-interest impedes the implementation of verification strategies that are beneficial for all firms while encouraging each firm to choose a verification strategy beneficial to itself. Incentives for verification activities can motivate a single firm to adopt verification strategies beneficial to all firms in the project, but these incentives must be offered judiciously to minimize unnecessary expenditures and prevent the abuse of goodwill. In this paper, we use game theory to model a contractor-subcontractor scenario, in which the subcontractor provides a component to the contractor, who further integrates it into their system. Our model uses belief distributions to capture each firm's epistemic uncertainty in their component's state prior to verification, and we use multiscale decision theory to model interdependencies between the contractor and subcontractor's design. We propose an incentive mechanism that aligns the verification strategies of the two firms and using our game-theoretic model, we identify those scenarios where the contractor benefits from incentivizing the subcontractor's verification activities.
  • Thumbnail Image
    Design of an IoT System for the Palletized Distribution Supply Chain with Model-Based Systems Engineering Tools
    Navarro, Nicolas; Horvath, Laszlo; Salado, Alejandro (MDPI, 2021-12-30)
    In recent years, Internet-of-Things technology (IoT) has been the subject of research in diverse fields of applications. IoT plays an essential role in transitioning enterprises towards a more interconnected paradigm of manufacturing, logistics, services, and business, known as Industry 4.0. This paper presents an operational concept for a system that implements IoT technology in pallets, which are used to move products along supply chains. These sensors will help us gain insight into the conditions experienced by products and unit loads. Having this capability will allow us to obtain the information necessary for better control of product distribution along the supply chain, and to design packaging that is more efficient and effective in protecting products during distribution. In this paper, we show how Model-Based Systems Engineering (MBSE) can be leveraged to create models that capture the required system behaviors, and we address the complexity of an IoT system within the domain of packaging and logistics applications.
  • Thumbnail Image
    Formal Inconsistencies of Expertise Aggregation Techniques Commonly Employed in Engineering Teams
    Stephen, Cynthia; Kannan, Hanumanthrao; Salado, Alejandro (MDPI, 2024-05-18)
    Engineering managers leverage the expertise of engineers in their teams to inform decisions. Engineers may convey their expertise in the form of opinions and/or judgements. Given a decision, it is common to elicit and aggregate the expertise from various engineers to capture a broader set of experiences and knowledge. Establishing an internally and externally consistent aggregation framework is therefore paramount to yield a meaningful aggregation, that is, to make sure that the expertise of each engineer is accounted for reasonably. However, we contend that most de facto aggregation techniques lack such consistency and lead to the inadequate use and aggregation of engineering expertise. In this paper, we investigate the consistency or lack thereof of various expertise aggregation techniques. We derive implications of such inconsistencies and provide recommendations about how they may be overcome. We illustrate our discussion using safety decisions in engineering as a notional case.
  • Thumbnail Image
    Socio-technical scales in socio-environmental modeling: Managing a system-of-systems modeling approach
    Iwanaga, Takuya; Wang, Hsiao-Hsuan; Hamilton, Serena H.; Grimm, Volker; Koralewski, Tomasz E.; Salado, Alejandro; Elsawah, Sondoss; Razavi, Saman; Yang, Jing; Glynn, Pierre; Badham, Jennifer; Voinov, Alexey; Chen, Min; Grant, William E.; Peterson, Tarla Rai; Frank, Karin; Shenk, Gary; Barton, C. Michael; Jakeman, Anthony J.; Little, John C. (2021-01)
    System-of-systems approaches for integrated assessments have become prevalent in recent years. Such approaches integrate a variety of models from different disciplines and modeling paradigms to represent a socioenvironmental (or social-ecological) system aiming to holistically inform policy and decision-making processes. Central to the system-of-systems approaches is the representation of systems in a multi-tier framework with nested scales. Current modeling paradigms, however, have disciplinary-specific lineage, leading to inconsistencies in the conceptualization and integration of socio-environmental systems. In this paper, a multidisciplinary team of researchers, from engineering, natural and social sciences, have come together to detail socio-technical practices and challenges that arise in the consideration of scale throughout the socioenvironmental modeling process. We identify key paths forward, focused on explicit consideration of scale and uncertainty, strengthening interdisciplinary communication, and improvement of the documentation process. We call for a grand vision (and commensurate funding) for holistic system-of-systems research that engages researchers, stakeholders, and policy makers in a multi-tiered process for the co-creation of knowledge and solutions to major socio-environmental problems.