Outline

1. Outline • world view of simulation • overview of ARENA • simple ARENA model: Model 03-01 • basic operations: Model 04-01

2. World Views of Simulation • discrete-event approach • application: systems with well-defined event times • modeling: definition of variables and events, including their interaction • characteristics • more suitable for discrete-event systems • requiring knowledge for users • activity scanning approach • application: systems where activities duration are defined by interaction of variables and events, e.g., system dynamics • modeling: definition of variables and their interaction • characteristics • more suitable for continuous-event systems • requiring knowledge for users

3. World Views of Simulation • process orientation approach • modeling: definition of the processes as experienced by entities • characteristics • minimum knowledge from users • applicable to both discrete- or continuous-event systems • only discrete-event approach being considered here

4. Process Oriented Simulation Languages • fixed number of “work stations” • fixed types of “entities” • possibly to have infinite supply for a type of entities • “process” as experienced by each type of entities

5. “work stations”: “entities”: “processes of entities”: Process Oriented Simulation Languages • for each station, specify • its characteristics • rules of operations • for each process of a type of entities, specify • the routing • the “treatment” at each station

6. Process Oriented Simulation Languages • process oriented approach: experienced of entities • for entities • routing, including rules to select stations • time and resources for service at stations • time and resources for moving around stations

7. Process Oriented Simulation Languages • for stations • the arrival process: inter-arrival time, number of arrivals batch, any dependency of inter-arrival times, etc. • the service process: number of service servers, service time distributions, any dependency of service times, resources for service • the queueing discipline: number of queues, priorities adopted in queues, rules to assign waiting customers to available servers • miscellaneous issues: waiting space, walking distance from queue to servers, type changes of customers, etc

8. Process Oriented Simulation Languages • from processes typed in • an underlying discrete-event (or activity scanning in applications not in this course) program being generated • good support in statistical analysis, reporting, and animation • ARENA: process oriented simulation package • pretty flexible, possible to • model in other approaches • interact with Spreadsheet, programming langagues

9. Process-Oriented Portion of ARENA • components of the process • arrival • service • characteristics of stations • service time • resources required • priority of customers in queues (to take resources) • rules for customers to direct to queues

10. Process-Oriented Portion of ARENA • components of the process (con’t) • transportation • moving as a time delay • moving that requires equipment • moving according to routes • others • schedule of resources • capacity changes of resources • up and down times of resources

11. ARENA • to learn how to learn • c:\Program Files\Rockwell Software\Arena7.0 • useful folders: Online Books , Book Examples , Examples , Smarts • Help in ARENA • Templates of ARENA

12. flexibility in modeling convenience in application Trade off of Flexibility in Modeling and Convenience in Applications

13. a drill press Model 03-01 GI/G/1 Queue • a drill press processing one type of product • interarrival times ~ i.i.d. exp(5) • service times ~ i.i.d. triangular (1,3,6) • all random quantities are independent • simulation: 20 time units one type of parts; parts come in and are processed one by one

14. Model 03-01 • to introduce • arrivals: Create Module • service: Process Module (resource) • departure: Dispose Module • Expression Builder – right click mouse • menu option: Setup • graphic library

15. Desirable Features • to introduce • automatic plotting number in queue, etc. • animation icon for resources: Resource Picture Placement Dialog • (click Resource Animation icon) • open new icon library .plb • association of icon to resource • animation icon for entities: Entity Pictures (Edit menu)

16. Desirable Features • report • WIP = Drill Press.Queue + Driller Instantaneous Utilization • difference between Instantaneous Utilization and Scheduled Utilization • difference between waiting time in Drill Press.queue and Wait time of entity

17. To Understand the Report • GI/G/1 queue with service times = 1 unit • interarrival time = 1.5 units • interarrival times = 0.8 units

18. Inconvenience of the Process-Oriented Approach • the protocol: not suitable for all cases • how to define entities for • a Newsboy problem • critical path method in project management • integration • possible to have entities for conceptual, logical, not physical flow

19. Chapter 4 Modeling Basic Operations & Inputs

20. Part A Process A EXPO(5) Tria(1,4,8) Rework 9% Part B 91% Process B Batches of 4 EXPO(30) Shipped Tria(3,5,10) Electronic Assembly/Test System Scrapped Part A TRIA(1,3,4) Part B WEIB (2.5, 5.3) 20% 80% EXPO(45) Salvaged & Shipped Sealer

21. Part A Scrapped Part A TRIA(1,3,4) Part B WEIB (2.5, 5.3) Process A 20% EXPO(5) Tria(1,4,8) 80% Rework EXPO(45) Salvaged & Shipped Sealer 9% Part B 91% create batches of 4 entities Process B Batches of 4 EXPO(30) Shipped Tria(3,5,10) processes chance create entities statistics time varying capacity unreliable system type-dependent service times Electronic Assembly/Test System to determine the number of racks

22. Models • Model 4.1: basic • Model 4.2: resource schedule, resource failure, frequency – time persistence statistics • Model 4.3: changing animation queue, changing entity picture, adding resource picture, adding variables and plots

23. Model 04-01 • ignore details • the 2-minute traveling times • the working hours of stations • schedule of the re-workers • failure of the sealer • the number of racks used