SIMULATION: Transactions of The Society for Modeling and Simulation International

Wainer, Gabriel A

doi: 10.1177/00375497241296146pmid: N/A

Zeigler, Bernard P; Koertje, Christian; Zanni, Cole

doi: 10.1177/00375497241264834pmid: N/A

In this tutorial review paper we explain the concept of homomorphism and identify some principles that justify homomorphism construction based on the homogeneity of structure and coupling in systems with multiple components. We discuss some simple examples to show how these underlying justifying conditions can arise. Examples include brain simulation, combat attrition, and the greatly reduced computational complexity represented by Pascal’s triangle. Homomorphism is also shown to be fundamental for constructing approximate low-resolution models. Models that simplify complex time-demanding simulation models are often used as surrogate or metamodels in system optimization. However, such models are fitted typically to computationally derived response surfaces and not structurally related directly to the originals using homomorphisms as described here. Along these lines, we show how homomorphism plays an essential role in a novel approach being developed to strongly control tree expansion in state space explorations of stochastic system simulation.

Fujimoto, Richard M

doi: 10.1177/00375497241261407pmid: N/A

This paper documents the origins and development of the parallel and distributed simulation field, especially as it relates to parallel discrete event simulation (PDES) technology. My focus is on the people and ideas that contributed to the creation and evolution of PDES technology over the past five decades. Much of this paper reviews the research conducted in academia and research laboratories that were the driving forces behind the development of PDES technology as well as subsequent efforts in government and industry to bring the technology to modeling and simulation practitioners. The origins of PDES technology lie in a fundamental technical issue called the synchronization problem. This problem is discussed, as well as the two main solution approaches that were created. The development of these approaches and their evolution to form the time management services of the High Level Architecture (HLA) standard are described, as well as the community of researchers and practitioners that formed in establishing this field. Commercialization efforts are discussed followed by a brief discussion of areas requiring further research. The importance of the Society for Modeling and Simulation International (SCS) and its flagship journal, Simulation, in the development of the field are discussed. Throughout this discussion, I provide my personal observations and take away lessons concerning the development of the field.

Mosterman, Pieter J; Vangheluwe, Hans

doi: 10.1177/00375497241298648pmid: N/A

One of the biggest achievements of the past half century has been making ever tinier structures. This miniaturization is at the foundation of three pillars that comprise the Digital Age: (1) computation, (2) digitization, and (3) communication. First, it is discussed how developments along these three pillars have affected the field of engineered systems. Next, the impact of these developments on the life cycle of engineered systems is examined from the perspective of (1) Information Technology (IT), (2) Embedded Technology (ET), and (3) Operation Technology (OT). A key value driver of IT is in the improved design approaches that are enabled by (1) the abundance of compute power and (2) connecting design activity within an organization as well as across organizations. Similarly, ET has provided much value by enabling the use of computation as the most important feature value driver of modern products. In turn, the large number of these software features relies on advances in communication networks as a critical infrastructure. Furthermore, digitization with remote sensing has opened up a trove of new features such as those in the area of autonomy. Finally, OT has benefited much from computation and digitization with communication features enabling current developments such as over-the-air updates. Building on the examination, a “design alive” outlook is presented that brings together the stages of system design and operation by live connectivity to continuously adapt each system on an individual basis and keep them performing in an optimal sense.

Uhrmacher, Adelinde M; Wilsdorf, Pia; Kreikemeyer, Justin N

doi: 10.1177/00375497241296878pmid: N/A

The notion of (self-)adaptation, according to J. Holland (1975), describes the process of iterative refinement of an entity’s behavior or structure to improve its performance in its environment. We argue that the potential role of (self-)adaptive simulation models has not been sufficiently acknowledged in the past. A focus on adaptive simulation will likely propel methodological advances in modeling and simulation and digital twinning, increasing its impact on solving urgent real-world problems. Therefore, we will review methods for including adaptation as part of or within simulation models and consequently discuss how simulation models themselves may become the subject of adaptation within and across simulation studies. We will identify different motivations for and types of adaptations within simulation studies by analyzing a family of simulation models. The need to automatically conduct various types of adaptations increases with the importance of online adaptations, e.g. as encountered in digital twins. Further methodological developments in unambiguously representing and intelligently processing the various knowledge sources used in simulation studies, domain-specific languages, analysis methods, self-adaptive software, and, last but not least, model learning are needed. Combining the adaptation within and of simulation models, we arrive at the vision of self-adaptive models, which are less subject to adaptation but become the central actors in their adaptation.

Wainer, Gabriel; Govind, Sasisekhar

doi: 10.1177/00375497241291871pmid: N/A

The growth of real-time embedded applications has surged in recent years, marked by both an increase in the number and complexity of tasks performed across various industries. Modeling and simulation (M&S) has been used for enhancing product quality while reducing lifecycle costs, primarily through improved testability and maintainability of real-time embedded systems applications, as M&S-based design approach allows for early hardware functionality testing, fosters collaboration between hardware and software teams, and shortens the product development cycle. The discrete-event system specification (DEVS) framework has been used for developing such discrete-event M&S systems. This article starts by highlighting the various DEVS publications in our journal over the past 20 years, reflecting the evolving landscape of simulation methodologies, which we organized into four categories: theory, methodology, tools, and applications. This curated selection reflects the diversity of topics and the evolution of scholarship within the field, encouraging further exploration and innovation. We conclude with recent research in the field, including our own research in real-time embedded systems development using DEVS software for modeling, simulation, and real-time execution of models. This paves the way for future discussions in this important field of research.