This document is the first draft specification of the Unified Model Characteristics for Engineering Simulation (UMC4ES). Engineering Simulation (ES) is defined by the NAFEMS ASSESS Initiative as "The use of physics-based mathematical (numerical) models and/or logical models, including relevant data derived from physical tests of a conceptual or real-world system, phenomenon, or process in studying its technical requirements and/or operational behavior." The physics-based mathematical models are used to perform behavioral response simulations of a system, whereas logical models are used to capture descriptive representations of a conceptual or real-world system, phenomenon, or process in studying its technical requirements and operational behavior.

Engineering Simulation metadata (ES Metadata) structures are currently being proposed by multiple initiatives, each of which takes a different approach to defining a pragmatic metadata structure based on its own perspective and goals. UMC4ES is an attempt to define a comprehensive set of model characteristics of interest for the complete range of ES Models that can be used across all approaches for implementing ES Metadata structures.

UMC4ES is not an implementation technique or a proposed standard. UMC4ES focuses on the definition of a unified set of model characteristics that may be used across multiple implementations or as the basis of a standard definition. These characteristics are assigned to an ES Model to support processes, activities, business purposes, and higher-level models. Processes and activities can be treated as other types of ES Models. However, further investigation may be needed to map all appropriate process & activity model characteristics.

UMC4ES will undergo an iterative development process that includes:

• Definition of the initial metadata structure
• Review/revision of the metadata structure based on the data structure of other metadata implementation approaches
• Mapping to/from the reviewed implementation perspectives
• Repeat Steps 2 & 3 for all implementation perspectives of interest

This draft of the UMC4ES specification only deals with the first three steps.