Worker Simulation using HLA

One field in the wide area of simulation applications is the field of manufacturing systems. Within it the human factor is of growing interest. To increase the efficiency and productivity of a company besides investment in new technologies the introduction of alternative working structures becomes more and more important. For the modeling of working structures the modeling of workers is significant. Most of the simulation systems available at the market offer elements for the modeling of workers in a more or less detailed way. Usually, the workers are implemented as a special resource with disposability and qualification. Worker elements in simulators are passive elements requested by a machine. In contrast, the worker elements in flexible working structures are active elements with many degrees of freedom in decision making. Because of the importance of the workers in the companies the modeling possibilities in the simulation systems have to be extended. Therefore, we propose a specification for worker modeling to extend existing systems. The specification supports the user by providing information about system elements with their attributes, parameters, and relations. A formal specification is needed for processing by a computer. For monolithical simulations there exists no standard specification language. Just for distributed simulations there is a new standard available, the High Level Architecture for Modeling and Simulation (HLA) developed by the DoD. We have tested the applicability of HLA for monolithical simulations. In our specification we have three components, the worker itself, the time model and a component for worker management. Every component represents a class with attributes, parameters and behavior. In a model several objects of each class, except the worker management class, can exist. This specification is simulator independent. Even though it is object-oriented, the implementation does not have to be. The components are extensible and adjustable. In the worker management some standard strategies are pre-definded, but special strategies can be supplemented. All information needed is in the worker management. We used HLA to describe the relations between the components and the participating parameters. We cannot describe the behavior of a component. These parts of the system we specified informal. So the specification is appropriate to build a monolithical simulation model including extended worker elements. However, with our approach every worker can be implemented as an autonomous entity. The material flow system, the worker management, the shift model, and every worker can interact in a distributed simulation system. Summarizing we can say that HLA is able to specify the field of monolithical simulation in an object-oriented way. We can specify the attributes, parameters and interactions between components. The information about the behavior of the components has to be added.