Data Collection for Simulation 1 Sources of Data

Data Collection for Simulation 1

Sources of Data �Computer Files ◦ Database ◦ Spreadsheets ◦ Raw Data �Video Records �Hard Copy Files & Documents �Interviews Existing �Video �Observation of running system �Interviews Observation 2

When & How Much to Collect? �To help design model �Interviews �Observation �Minimum necessary �To obtain input parameters �Adequate amount for statistical tests Preliminary Detailed 3

What to collect? �Data to Determine ◦ Layout of system ◦ Entities of importance ◦ Flow of entities ◦ Problems �Rough times �Data for ◦ Arrivals ◦ Services ◦ Queues ◦ Anomalies estimates of Preliminary Detailed 4

What to collect? More… �Focus on data related to problems & objectives �Enough data for statistical significance �Continuous data 5

Collection Schedule Depends on Simulation Objectives & Level of Activity �Days of week ◦ Busiest, Typical, Slowest ◦ All, Certain ones �Time of day ◦ Busiest, Typical, Slowest ◦ Start-up, Wind-down �Length of time ◦ Adequate numbers 6

How Many Collectors? �Minimum of 2 collectors for each major entity ◦ One watches & times; One records �Factors ◦ Level of Activity ◦ Proximity of areas to be observed ◦ Visibility 7

Collection Guidelines Collectors can have NO Effect on the system! �Should be located “outside” the system �Cannot utilize any resource �Never interfere �Best if not seen 8

Collection Process �Collect information necessary to reproduce system activity ◦ NOTE: That is not everything!! �Example: Single Queue & Server System ◦ Arrival Time, Begin Service, End Service ◦ Allows calculation of all remaining values of interest. How? �Time Units ◦ Smallest necessary (seconds, minutes…) 9

Sample Collection Form Single Queue-Single Server Customer Number 1 Arriva l Time Hr: Min: Sec Begin Service End Service 0: 0: 0 0: 5: 26 2 0: 3: 30 0: 5: 26 0: 10: 45 4 0: 13: 24 0: 15: 50 0: 19: 55 3 0: 12: 0 0: 15: 50 Comments? ? 10

Data Collection Plan �A description of process that includes ◦ Method(s) for collection ◦ Timeline for data collection process & completion ◦ List of data items to be collected ◦ Number of collectors ◦ Dates & times of actual data collected (if not observed in real-time) ◦ Justification for each of the above ◦ Diagrams as necessary 11

Data Collection Report �A description of completed collection process that includes ◦ Restatement of “Plan” & any changes to original plan ◦ Results of Statistical Analysis of data ◦ ◦ �Graphs, Averages, Max, Min Summary of results Relation of results to clients objectives Recommendations Diagrams as necessary 12

Data Collection Assignment �Select System �Design & Write Data Collection Plan �Observe & Collect �Complete Data Analysis �Write Data Collection Report 13