Proceedings of the 2013 Winter Simulation Conference R. Pasupathy, S.-H. Kim, A. Tolk, R. Hill, and M. E. Kuhl, eds A CONCEPTUAL DESIGN TOOL TO FACILITATE SIMULATION MODEL DEVELOPMENT: OBJECT FLOW DIAGRAM Allen G Greenwood Pawel Pawlewski Mississippi State University Poznan University of Technology 260 McCain Engineering Building Dept. of Management Engineering P. O. 9542 ul.Strzelecka 11 Mississippi State, MS, 39762, USA Poznan, 60-965, POLAND Grzegorz Bocewicz Koszalin University of Technology Śniadeckich 2 Koszalin, 75-453, POLAND ABSTRACT This paper describes a diagramming methodology, referred to as an Object Flow Diagram (OFD), that is intended to be a key component in the conceptual design of a discrete-event simulation model. It provides an effective means for representing salient system elements and their relationships. It draws upon other popular system diagramming methods, such as IDEF0 and IDEF3, to bring the relevant aspects of these tools to the simulation modeler. It is intended to be easy to apply, with few symbols and constructs, yet robust and comprehensive enough to represent a wide variety of systems. It is simulation software neutral and thus provides a basis for model development in any language. A simple example is used to illustrate the approach. The methodology has been used in industry projects and in simulation courses. 1 INTRODUCTION It is important in any modeling, but especially in simulation modeling, to have a clear understanding of the system being considered. Modeling is basically representing, in some abstract way, the key elements and interactions that drive a system’s behavior as well as its structure. Therefore, it is paramount for mod- elers to effectively capture and represent their understanding of a system so that they include the correct and the salient aspects of the system in their model. Similarly, modelers need to communicate their under- standings and representations to others. Diagrams, symbolic visual representations of information, effectively support critical thinking and problem solving (Kosslyn 1980; Larkin and Simon 1987). Larkin and Simon (1987) indicate diagrams are superior to verbal descriptions for problem solving since they group together information that is used to- gether, use location to group information about a single element, and support a large number of perceptual inferences. Modeling is a process – a set of coordinated activities that transform input into output. As a process, modeling transforms needs, knowledge, and data into measures, new knowledge, and satisfied needs. In simulation, the key transform in this process is the simulation model. Execution of the model provides measures of system performance under varying conditions that provide the basis for analysis that ulti- mately supports decisions and actions. Of course, the quality of the results depends on the quality of the input – the definition and specification for the model. 1292 978-1-4799-2076-1/13/$31.00 ©2013 IEEE