Arena modeling Conceptual model can be converted into

Arena modeling Conceptual model can be converted into Arena model: connected building blocks. Building blocks must be parameterized. Arena interface demo

Basic blocks Create / Process / Dispose building blocks.

Adding resources

Splitting transitions Seize two resources, release one when finished. Not directly possible in Arena: Seize Delay: seize and keep all Seize Delay Release: seize and return all. Implementation: split!

Ferry implementation (ARENA) Split marked transitions. Add "case" class for A 2 B and B 2 A. Create once, do not dispose. Resources cannot be added.

Parameterization Arena building blocks are parameterized. Default parameters are set when installing blocks. Resource consumption/production parameters inferred from conceptual model. Parameters to be added: - arrival distribution for create blocks (often negexp with a certain intensity), - duration for process blocks (sometimes 0 for blocks that result from splitting.

Testing After model construction, animated simulation is done. Press ► button and observe. Correct syntax errors. Unexpected results: adapt or explain. If found correct, choose Run Setup, then Replication parameters tab. Select a moderate replication length and then press ►►, wait until completion and examine the report. Standard report: queue lengths for resources, processing times for entities.

Decide block Alternative paths:

Assign block Assignment: - attributes (per entity) - variables (global) "ordinary" programming

Other blocks In some cases, the simulation should report on special data (e. g. expressions involving attributes and variables). This can be achieved by including the Report block. Separate block is used for duplication of entities. Batch block is used for grouping entities. For other Arena blocks, see the Arena book W. D. Kelton, R. P. Sadowski, and D. Sturrock. Simulation with Arena, 3 rd ed. Mc. Graw-Hill, New York, 2004.

Classwork A factory fabricates two types of products, X and Y and has (multiple) machines of types A, B and C respectively. Orders for product X have to pass through A and then C. Orders for Y have to pass through B and then C. The machine types A and B are different configurations of the same machine. It is possible to reconfigure a machine from type A into type B and vice versa. If no cases are waiting for resource A and the queue length for cases waiting for resource B exceeds N, a machine of type A is reconfigured to type B. If no cases are waiting for resource B and the queue length for cases waiting for resource A exceeds M, a machine of type B is reconfigured to type A. Give conceptual model and Arena implementation.

Parameters interarrival times X, Y : 1. 0, resp. 0. 85 minutes. machines A, B and C available: 2, 2, 4 (initially). Processing duration: 1. 6 minutes per A/B step and 1. 8 minutes for any C step. Reconfiguration: 4 minutes (both A 2 B and B 2 A). Find most effective N, M.