SIMULATION: Transactions of The Society for Modeling and Simulation International

Lukas, D.; Soukupova, V.; Pan, N.; Parikh, D. V.

doi: 10.1177/0037549704047307pmid: N/A

Liquid movement in 3-D fibrous materials is studied in this article by means of Monte Carlo simulation based on the Ising model with so-called Kawasaki kinetics. Computer simulation algorithms are then developed in accordance with the standard liquid wicking rate tests from both EDANA and INDA, and the simulation results provide information of liquid wicked into computer-generated fiber assemblies as a function of time. The work focuses mainly on the relationship between fiber orientation and the liquid wicking rate, while other geometrical parameters of the fiber mass remain fixed. Furthermore, this simulation also presents dynamic data of both liquid mass uptake and energy changes of the system. The results are in agreement with known experimental evidence.

McKenzie, Frederic D.; Petty, Mikel D.; Xu, Qingwen

doi: 10.1177/0037549704050185pmid: N/A

Software architecture is high-level software design dealing with the structure and organization of large software systems. Architecture description languages (ADLs) are languages designed to represent software designs at the architecture level. ADLs are not widely used in the development of simulation systems. This research investigates the utility and effectiveness of ADLs for architecture-level design and analysis of simulation systems. Experimental applications of two ADLs to the specification and analysis of simulation architectures were conducted. Rapide was used to model the EnviroFed federation architecture and analyze data volume with and without interest management. Acme was used to model the ModSAF federate architecture and to analyze execution time at the component and federate levels in ModSAF. The experiments showed that ADLs could be used to discover important features of simulation system architectures.

Nutaro, James; Sarjoughian, Hessam

doi: 10.1177/0037549704050919pmid: N/A

This article presents a framework for distributed simulation that is based on system-theoretic and logical-process concepts. The framework describes a three-part worldview for developing simulation models. These are modeling formalisms, abstract simulators, and computational environments. A unified view of time and causality allows for the application of system-theoretic notions of causality within a distributed simulation environment. Within this framework, the authors introduce a unified notion of causality for use in parallel simulations. Furthermore, they describe an approach for developing distributed simulation models that evolve from modeling constructs to simulation algorithms and their implementations. The framework is exemplified using the discrete event system specification (DEVS) modeling formalism, its abstract simulator, and a parallel algorithm that implements the abstract simulator.

Le Goc, Marc

doi: 10.1177/0037549704050920pmid: N/A

SACHEM is an extensive large-scale, real-time, knowledge-based system designed to monitor and diagnose complex dynamic processes such as blast furnaces. This article aims at illustrating the way the paradigm of discrete events allowed the design of SACHEM as a recursive abstraction process of discrete events. This recursive abstraction process is the basis of a “perception-based” approach of diagnosis. A first formalization of this kind of diagnosis is proposed and illustrated with the example of the perception of a “scaffolding” phenomenon. Some considerations about blast furnaces, SACHEM, and its development are also provided to argue the operational flavor of a“perception-based”approach for diagnosis.

Choi, Jou-Young; Ruzzene, Massimo; Bauchau, Olivier A.

doi: 10.1177/0037549704050915pmid: N/A

This article presents a numerical model for the simulation of the flight mechanics behavior of flexible supercavitating vehicles. Supercavitating vehicles exploit supercavitation as a means to reduce drag and increase underwater speed. In the proposed formulation, the vehicle’s rigid body motion is described by six degrees of freedom, which define pitch, yaw, and roll motion and the displacement of the center of gravity with respect to an inertial reference system. The developed numerical model predicts the dynamic response of the vehicles resulting from perturbation of the control surfaces and assigned maneuvers. The results highlight the potential instability of the vehicles’ behavior and its sensitivity to the considered control maneuvers. The analysis is motivated by the need of accurately modeling the structural characteristics of supercavitating vehicles to estimate vibrations in the structure and to envision and design systems that improve their guidance and control efficiency.

Liang, Jinsong; Chen, YangQuan; Guo, Bao-Zhu

doi: 10.1177/0037549704050183pmid: N/A

Although boundary control of linear partial differential equations has become an important research area, there is still no readily available simulation tool to help researchers analyze and design. In this article, a simulation method for some typical boundary control problems, combining symbolic math and a numerical method, is presented with application examples. In the intermediate steps of the simulation, an important by-product, transfer function of the controlled system, can be obtained, which makes the design of more advanced boundary controllers possible and much easier.