EXERCISE– SIMPLE AIRPORT (PART 3) – MODIFIED
INITIAL FLOW (CNTD FROM MOD1)
INITIAL MODEL
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SETUP INFO
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ARRIVAL RATE
¢ Passengers do not arrive at a constant rate through the entire day in a real airport (even though they may arrive randomly), so we should expand our model to handle such phenomenon.
¢ The changing rate in SIMIO is modelled using a Rate Table
¢ Arrivals are only present from 5am to 8pm for a total of 15 hours each day
CREATING A RATE TABLE
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¢ Create a Rate table from Data tab and then selecting Rate Tavle
¢ Name: PassengerArrivalRate
¢ Number of Intervals: 15
¢ Note arrival rate is arrivals per hour
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ASSIGNING A RATE TABLE
¢ Modify the source to read from the rate table that you just created
¢ Set Arrival mode to : Time Varying Arrival Rate
¢ Set Rate table to the one that we just created: PassengerArrivalRate
INITIAL RESULTS
¢ Run the model
¢ Note: If the length of the simulation exceeds the length of the rate table then the rate table will repeat itself, until the simulation is terminated.
¢ If the duration needs to be longer and there are no arrivals during that time then the rate table should contain zeroes accordingly.
PASSENGER T YPES
¡ In an actual airport more than one type of passenger arrives.
¡ Some are continental travelers while others are inter- continental
¡ Some have handicaps that require special attention or travel with families
¡ The different types of passengers result inf different processing times
¡ To model these three cases we will use a combination of state variable and properties to store information
¡ There is a 33% chance for each type of passenger to arrive to our airport.
¡ The processing times at the curbside and check in varies with the type of passenger.
STATE VARIABLES
¢ We need to define a characteristic of the MODEL ENTITY. That will have its own value and instance for each entity that gets in the system –each passenger
¢ State variables are user defined characteristics whose values can be re-assigned.
¢ Other times when we want to define a characteristic for the whole model, we use a MODEL state variable
SET UP INTEGER STATE VARIABLE
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¢ Go to Model Entity – States – Definition
¢ Integer state
¢ We will number (like an
ID) our passenger types ¢ Name: PassType
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ASSIGN VALUES TO STATE VARIABLE
¢ We need to assign values to the state variable
¢ To obtain random assignment of passenger type with probability of 33% to each
type of entities we can use the Discrete distribution: ¢ Random.Discrete(1, 0.33, 2. 0.66, 3, 1.00)
¢ We are going to use the Source object and do a “State Assignment”
DATA TABLE
¢ We need to store the information for the check in times
¢ We will use a data table to store the information
¢ We will create a table with 3 columns, the PassengerPriority, CurbsideCheckIn and InsideCheckIn
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DEFINING THE DATA TABLE COLUMNS
¢ PassPriority ¢ Integer
¢ CurbsideCheckIn ¢ Expression
¢ InsideCheckIn
SPECIFYING THE PROCESSING TIMES
¢ Set up the Curbside Processing Time:
¢ TblPassenger[ModelEntity. Pass Type]. CurbsideCheckI n
¢ Set up the Curbside Processing Time:
¢ TblPassenger[ModelEntity. Pass Type]. CurbsideCheckI n
PERFORMANCE MEASURES
¢ What is the average check in time for a Passenger?
¢ What are the average wit times for the curbside and inside check in?
¢ What are the utilizitions