1. F Day 3 Section 5 - Event Approach to Simulation Events
Implementation of the Event Approach
Canceling Events
Exercise 5
Section 6 - Simulation Output Analysis
Random Numbers and Statistics
Modernizing a Bank - with replications
Presentation Graphics
Exercise 6 F
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2. Section 6 - Simulation Output Analysis
Part 1 - Random Numbers and Statistics
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 —————————————— 6-2

3. Generating Random Numbers
Multiplicative congruent technique
Single stream of numbers between 0.0 and 1.0.
Provide a number called a seed
Do the arithmetic
Results are the random value and the seed for the next draw.
Period > 2 billion numbers on a 32 bit machine
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 —————————————— 6-3

4. Multiple Random Number Streams
Seed.v is a 1-dimensional, integer array of size 10.
It holds the current value of seeds for 10 different streams.
Let .PROBABILITY = random.f(3)
List seed.v(3)
Seeds are 100,000 numbers apart
Can access and change seed.v
Release seed.v
Reserve seed.v as 200
For I = 1 to 200 Do
Read seed.v(I)
Loop ''I = 1 to 200 do
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 —————————————— 6-4

5. Reproducibility of Random Numbers
Let .SAVE.SEED.1 = seed.v(1)
<statements>
Let seed.v(1) = .SAVE.SEED.1
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 —————————————— 6-5

6. Replications No stop statements Reset output variables
Let event set empty
All resources relinquished
Reset output variables
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7. 3 Define I as an integer variable 4 5 Call INITIALIZE 6
1 Main 2
3 Define I as an integer variable 4
5 Call INITIALIZE 6
7 Print 6 lines thus
Pacific Port Problem with Replications
Number of Average Maximum
Ships Unloaded Delay Time Delay Time
For I = 1 to 20 do 15
Use unit 6 for output
Activate a GENERATOR now
Start simulation 19
Print 1 line with NO.OF.SHIPS.SERVED,
SUM.SHIP.DELAY / NO.OF.SHIPS.SERVED and
MAX.SHIP.DELAY thus
*** **.** **.** 24
Let time.v = 0
Let NO.OF.SHIPS.SERVED = 0
Let SUM.SHIP.DELAY = 0
Let MAX.SHIP.DELAY = 0 29
Loop ''I = 1 to 20 do 31
32 End
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 —————————————— 6-7

8. Pacific Port Problem with Replications
Number of Average Maximum
Ships Unloaded Delay Time Delay Time
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9. Collecting Statistics
Number of occurrences
Sum
Mean
Sum of squares
Mean square
Variance
Standard deviation
Maximum
Minimum
Histogram
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10. Collecting Statistics (continued)
Select a global variable or attribute you want statistics on.
Write one statement in the preamble to collect them.
In Preamble
Accumulate SHORTEST.LINE.LENGTH as the minimum,
LONGEST.LINE.LENGTH as the maximum,
AVERAGE.LINE.LENGTH as the mean,
SPREAD as the std.dev and
LINE.HISTOGRAM (0 to 20 by 1) as the histogram
of N.Q.RUNWAY
In another routine
List SHORTEST.LINE.LENGTH,
LONGEST.LINE.LENGTH,
AVERAGE.LINE.LENGTH and
SPREAD
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

11. Collecting Statistics (continued)
SIMSCRIPT II.5 will set up the required counters to collect the required statistics
SIMSCRIPT II.5 will monitor the global variable N.Q.RUNWAY
Every time N.Q.RUNWAY is about to change, SIMSCRIPT II.5 will intercept control and pass it to the library routines that update the counters.
Then it lets N.Q.RUNWAY change.
When you want a value of a statistic, SIMSCRIPT II.5 calls a function that calculates it using the current values of the counters.
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

12. Collecting Statistics (continued)
Suppose you want to collect daily and weekly statistics on the same variable.
In Preamble
Accumulate
DAILY.AVERAGE.LINE.LENGTH as the DAILY mean and
WEEKLY.AVERAGE.LINE.LENGTH as the WEEKLY mean
of N.Q.RUNWAY
In another routine
For I = 1 to 7 do ''days
Start simulation
List DAILY.AVERAGE.LINE.LENGTH
Reset DAILY totals of N.Q.RUNWAY
Loop ''I = 1 to 7 do
List WEEKLY.AVERAGE.LINE.LENGTH
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

13. Using Statistics to Make Decisions
May need to look at all possibilities before making a decision
Length of shortest line
For each RUNWAY do
Compute SHORTEST.LINE as the minimum
of N.Q.RUNWAY(RUNWAY)
Loop ''each RUNWAY
Runway with shortest line
Compute BEST.RUNWAY as the minimum(RUNWAY)
Request 1 RUNWAY (BEST.RUNWAY)
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

14. Accumulate and Tally Time
Accumulate gives the time averaged statistic. Used when the length of time spent at a value is important, as for example, in queue lengths.
Tally does not time average, as for example, in time waited in queue. X
Time 1 2 t
Accumulate gives a value of almost 2.0
Tally gives a value of 1.5
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15. This page is intentionally blank
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16. Section 6 - Simulation Output Analysis
Part 2 - Modernizing a Bank - with Replications
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

17. Bank Teller Problem
Model bank with single line or multiple lines for tellers
Look at range of tellers for each case
Run replications for each case and number of tellers
Customer inter-arrival times and service times are exponentially distributed
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

18. Bank Teller Problem (continued)
In the multi-line system, an arriving customer will go to any available teller. If no teller is available, the customer will choose the shortest line and wait there until served. When the bank closes, no more customers are admitted, but all are served before the tellers leave.
Results will be printed after each replication as well as overall.
The results desired are:
1. Average utilization of tellers
2. Average and maximum waiting line length
3. A histogram of waiting line length
4. Average waiting time of customers
5. A histogram of the waiting time in five minute increments
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

19. 3 '' Modernizing a Bank - CACI Products Company
1 Preamble 2
3 '' Modernizing a Bank - CACI Products Company
4 '' files: SIMBANK.SRC 5
6 Normally mode is undefined 7
8 Processes include
GENERATOR and
CUSTOMER 11
Resources include
TELLER 14
Define CASE as a text variable 16
Define MIN.TELLERS,
MAX.TELLERS and
NO.OF.REPLICATIONS
as integer variables 21
Define MEAN.INTERARRIVAL.TIME,
MEAN.SERVICE.TIME,
DAY.LENGTH and
WAITING.TIME
as real variables 27
Accumulate DLY.UTILIZATION as the DAILY average of N.X.TELLER 29
Accumulate DLY.AVG.QUEUE.LENGTH as the DAILY average and
DLY.MAX.QUEUE.LENGTH as the DAILY maximum
of N.Q.TELLER 33
Tally DLY.MEAN.WAITING.TIME as the DAILY mean of WAITING.TIME 35
Accumulate UTILIZATION as the average of N.X.TELLER
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

20. 38 Accumulate AVG.QUEUE.LENGTH as the average, 37
Accumulate AVG.QUEUE.LENGTH as the average,
MAX.QUEUE.LENGTH as the maximum and
QUEUE.HISTOGRAM (0 to 20 by 1) as the histogram
of N.Q.TELLER 42
Tally MEAN.WAITING.TIME as the mean and
WAIT.HISTOGRAM (0 to 100 by 5) as the histogram
of WAITING.TIME 46
47 End
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21. 8 Define .START.TIME as a real variable 9
1 Main
2 Define .NO.OF.TELLERS,
REPLICATION,
SAVESEED1 and
SAVESEED2
6 as integer variables 7
8 Define .START.TIME as a real variable 9
Let .SAVESEED1 = seed.v(1)
Let .SAVESEED2 = seed.v(2) 12
Call READ.DATA 14
For .NO.OF.TELLERS = MIN.TELLERS to MAX.TELLERS Do
Call INITIALIZE.TELLERS
Given
NO.OF.TELLERS 20
For .REPLICATION = 1 to NO.OF.REPLICATIONS Do
Let .START.TIME = time.v 24
Activate a GENERATOR now
Start simulation
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

22. 35 Reset DAILY totals of N.X.TELLER(TELLER), 36 N.Q.TELLER(TELLER) and
Call DAILY.REPORT
Given
REPLICATION,
START.TIME and
NO.OF.TELLERS 32
For each TELLER Do
Reset DAILY totals of N.X.TELLER(TELLER),
N.Q.TELLER(TELLER) and
WAITING.TIME
Loop ''each TELLER
Loop ''.REPLICATION = 1 to NO.OF.REPLICATIONS 40
Call FINAL.REPORT
Let time.v = 0.0
Let seed.v(1) = .SAVESEED1
Let seed.v(2) = .SAVESEED2 45
For each TELLER Do
Reset totals of N.X.TELLER(TELLER),
N.Q.TELLER(TELLER) and
WAITING.TIME 51
Loop ''each TELLER do
Loop ''.NO.OF.TELLERS = MIN.TELLERS to MAX.TELLERS 54
55 End
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

23. Enter case to be run (Single-queue (S) or Multi-queue (M): 5 Read CASE
1 Routine READ.DATA 2
3 Print 1 line thus
Enter case to be run (Single-queue (S) or Multi-queue (M):
5 Read CASE
6 Let CASE = upper.f(CASE) 7
8 Print 1 line thus
Enter minimum number of tellers:
Read MIN.TELLERS 11
Print 1 line thus
Enter maximum number of tellers:
Read MAX.TELLERS 15
Print 1 line thus
Enter number of replications:
Read NO.OF.REPLICATIONS 19
Print 1 line thus
Enter mean time between customer arrivals (in minutes):
Read MEAN.INTERARRIVAL.TIME 23
Print 1 line thus
Enter mean time for servicing a customer (in minutes):
Read MEAN.SERVICE.TIME 27
Print 1 line thus
Enter length of time that bank is open for one day (in hours):
Read DAY.LENGTH 31
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

24. 34 Print 10 lines with MIN.TELLERS, 35 MAX.TELLERS,
Skip 2 output lines 33
Print 10 lines with MIN.TELLERS,
MAX.TELLERS,
NO.OF.REPLICATIONS,
MEAN.INTERARRIVAL.TIME,
MEAN.SERVICE.TIME and
DAY.LENGTH thus
COMPARISON OF SINGLE AND MULTI-QUEUE BANK OPERATIONS
The number of tellers ranges from * to *.
There are * replications for each number of tellers:
Customers arrive according to an exponential distribution
of inter-arrival times with a mean of *.** minutes.
Service time is exponentially distributed
with a mean of **.** minutes.
The bank doors are closed after *.** hours each day
But all customers inside are served.
Skip 2 output lines 51
52 End ''READ.DATA
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

25. 1 Routine INITIALIZE.TELLERS 2 Given 3 .NO.OF.TELLERS 4
5 Define .NO.OF.TELLERS as an integer variable 6
7 If N.TELLER is not zero
Destroy every TELLER
9 Endif ''N.TELLER is not zero 10
If CASE = "S" ''single queue case
Create every TELLER(1)
Let U.TELLER(1) = .NO.OF.TELLERS
Else ''multi-queue case
Create every TELLER(.NO.OF.TELLERS)
For each TELLER Do
Let U.TELLER(TELLER) = 1
Loop ''each TELLER do
Endif ''CASE = "S" 21
22 End ''INITIALIZE.TELLERS
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

26. 3 Define .TIME.TO.CLOSE as a real variable 4
1 Process GENERATOR 2
3 Define .TIME.TO.CLOSE as a real variable 4
5 Let .TIME.TO.CLOSE = time.v + (DAY.LENGTH / hours.v) 6
7 Until time.v >= .TIME.TO.CLOSE
8 Do
Activate a CUSTOMER now
Wait exponential.f(MEAN.INTERARRIVAL.TIME,1) minutes
Loop ''time.v >= .TIME.TO.CLOSE do 12
13 End ''GENERATOR
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

27. 3 Define .ARRIVAL.TIME as a real variable 4
1 Process CUSTOMER 2
3 Define .ARRIVAL.TIME as a real variable 4
5 Define .MY.CHOICE as an integer variable 6
7 Let .ARRIVAL.TIME = time.v
8 If CASE = "S" ''single queue case
Let .MY.CHOICE = 1
Else ''multi-queue case
For each TELLER
with N.X.TELLER(TELLER) = 0
Find the first case
If found
Let .MY.CHOICE = TELLER
Else ''they're all busy
For each TELLER Do
Compute .MY.CHOICE as the minimum(TELLER)
of N.Q.TELLER(TELLER)
Loop ''each TELLER
Endif ''found
Endif ''CASE = "S" 24
Request 1 TELLER(.MY.CHOICE) 26
Let WAITING.TIME = (time.v - .ARRIVAL.TIME) * hours.v * minutes.v 28
Work exponential.f(MEAN.SERVICE.TIME, 2) minutes 30
Relinquish 1 TELLER(.MY.CHOICE) 32
33 End ''CUSTOMER
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

28. 7 Define .REPLICATION.NUMBER and 8 .NO.OF.TELLERS
1 Routine DAILY.REPORT
2 Given
REPLICATION.NUMBER,
START.TIME,
NO.OF.TELLERS 6
7 Define .REPLICATION.NUMBER and
NO.OF.TELLERS
9 as integer variables 10
Define .START.TIME as a real variable 12
If .REPLICATION.NUMBER = 1
Start new page
Print 5 lines with .NO.OF.TELLERS thus
Number of tellers = *
Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Endif ''.REPLICATON.NUMBER = 1
For each TELLER Do
Print 1 line with (time.v - .START.TIME) * hours.v,
DLY.UTILIZATION(TELLER)/U.TELLER(TELLER),
DLY.AVG.QUEUE.LENGTH(TELLER),
DLY.MAX.QUEUE.LENGTH(TELLER) and
DLY.MEAN.WAITING.TIME thus
*.** ***.* **.* ** ****
Loop ''each TELLER 31
32 End ''DAILY.REPORT
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29. 3 Define .I as an integer variable 4 5 Print 2 lines thus
1 Routine FINAL.REPORT 2
3 Define .I as an integer variable 4
5 Print 2 lines thus
Average over all replications: 8
9 For each TELLER Do
Print 1 line with UTILIZATION(TELLER) / U.TELLER(TELLER),
AVG.QUEUE.LENGTH(TELLER),
MAX.QUEUE.LENGTH(TELLER) and
MEAN.WAITING.TIME thus
***.* **.* ** ****
Loop ''each TELLER
Skip 3 lines 18
Print 3 lines with WAIT.HISTOGRAM(1) and
QUEUE.HISTOGRAM(1,1) * 100 /time.v thus
Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T < *** *.* 24
For .I = 2 to 20 Do
Print 1 line with 5 * (.I - 1),
* .I,
WAIT.HISTOGRAM(.I),
I - 1 and
QUEUE.HISTOGRAM(1,.I) * 100 / time.v thus
** <= T < ** *** *** *.*
Loop ''I = 1 to 20 34
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

30. 35 Print 1 line with WAIT.HISTOGRAM(21) and
QUEUE.HISTOGRAM(1,21) * 100 /time.v thus
100 <= T *** *.* 38
39 Read as / using unit 5 40
41 End ''FINAL.REPORT
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

31. Enter case to be run (Single-queue (S) or Multi-queue (M): S
Enter minimum number of tellers: 1
Enter maximum number of tellers: 3
Enter number of replications: 5
Enter mean time between customer arrivals (in minutes): 5
Enter mean time for servicing a customer (in minutes): 10
Enter length of time that bank is open for one day: 8
COMPARISON OF SINGLE AND MULTI-QUEUE BANK OPERATIONS
The number of tellers ranges from 1 to 3.
There are 5 replications for each number of tellers:
Customers arrive according to an exponential distribution
of inter-arrival times with a mean of 5.00 minutes.
Service time is exponentially distributed
with a mean of minutes.
The bank doors are closed after hours each day
But all customers inside are served.
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

32. Finish Teller Queue Length Average Customer
Number of tellers = 1
Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Average over all replications:
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

33. Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T <
5 <= T <
10 <= T <
15 <= T <
20 <= T <
25 <= T <
30 <= T <
35 <= T <
40 <= T <
45 <= T <
50 <= T <
55 <= T <
60 <= T <
65 <= T <
70 <= T <
75 <= T <
80 <= T <
85 <= T <
90 <= T <
95 <= T <
100 <= T
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

34. Finish Teller Queue Length Average Customer
Number of tellers = 2
Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Average over all replications:
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

35. Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T <
5 <= T <
10 <= T <
15 <= T <
20 <= T <
25 <= T <
30 <= T <
35 <= T <
40 <= T <
45 <= T <
50 <= T <
55 <= T <
60 <= T <
65 <= T <
70 <= T <
75 <= T <
80 <= T <
85 <= T <
90 <= T <
95 <= T <
100 <= T
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

36. Finish Teller Queue Length Average Customer
Number of tellers = 3
Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Average over all replications:
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

37. Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T <
5 <= T <
10 <= T <
15 <= T <
20 <= T <
25 <= T <
30 <= T <
35 <= T <
40 <= T <
45 <= T <
50 <= T <
55 <= T <
60 <= T <
65 <= T <
70 <= T <
75 <= T <
80 <= T <
85 <= T <
90 <= T <
95 <= T <
100 <= T
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

38. Enter case to be run (Single-queue (S) or Multi-queue (M): M
Enter minimum number of tellers: 1
Enter maximum number of tellers: 3
Enter number of replications: 5
Enter mean time between customer arrivals (in minutes): 5
Enter mean time for servicing a customer (in minutes): 10
Enter length of time that bank is open for one day: 8
COMPARISON OF SINGLE AND MULTI-QUEUE BANK OPERATIONS
The number of tellers ranges from 1 to 3.
There are 5 replications for each number of tellers:
Customers arrive according to an exponential distribution
of inter-arrival times with a mean of 5.00 minutes.
Service time is exponentially distributed
with a mean of minutes.
The bank doors are closed after hours each day
But all customers inside are served.
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

39. Finish Teller Queue Length Average Customer
Number of tellers = 1
Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Average over all replications:
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

40. Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T <
5 <= T <
10 <= T <
15 <= T <
20 <= T <
25 <= T <
30 <= T <
35 <= T <
40 <= T <
45 <= T <
50 <= T <
55 <= T <
60 <= T <
65 <= T <
70 <= T <
75 <= T <
80 <= T <
85 <= T <
90 <= T <
95 <= T <
100 <= T
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

41. Finish Teller Queue Length Average Customer
Number of tellers = 2
Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Average over all replications:
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

42. Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T <
5 <= T <
10 <= T <
15 <= T <
20 <= T <
25 <= T <
30 <= T <
35 <= T <
40 <= T <
45 <= T <
50 <= T <
55 <= T <
60 <= T <
65 <= T <
70 <= T <
75 <= T <
80 <= T <
85 <= T <
90 <= T <
95 <= T <
100 <= T
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

43. Number of tellers = 3 Finish Teller Queue Length Average Customer
Time Utilization Average Maximum Waiting time
(Hours) (Minutes)
Average over all replications:
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

44. Waiting Time Number Who Waited Queue Length Percentage
(minutes) This Time of Time
T <
5 <= T <
10 <= T <
15 <= T <
20 <= T <
25 <= T <
30 <= T <
35 <= T <
40 <= T <
45 <= T <
50 <= T <
55 <= T <
60 <= T <
65 <= T <
70 <= T <
75 <= T <
80 <= T <
85 <= T <
90 <= T <
95 <= T <
100 <= T
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

45. Section 6 - Simulation Output Analysis
Part 3 - Presentation Graphics
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

46. Presentation Graphics
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

47. Displaying a Single Variable
Preamble
Resources include PASSENGER.AGENT
Display variables include N.Q.PASSENGER.AGENT
End ''Preamble
Main
Show N.Q.PASSENGER.AGENT with "QUEUE.GRF"
End ''Main
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

48. Displaying a Histogram
Preamble
Define WAITING.TIME as a real variable
Define LOW, HIGH and DELTA as integer variables
Tally WAITING.TIME.HISTOGRAM (LOW to HIGH by DELTA)
as the dynamic histogram of WAITING.TIME
End ''Preamble
Main
Show WAITING.TIME.HISTOGRAM with "WAIT.GRF"
End ''Main
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

49. Displaying a Clock Preamble Define CLOCKTIME as a double variable
Display variables include CLOCKTIME
End ''Preamble
Main
Let timesync.v = 'CLOCK.UPDATE'
Show CLOCKTIME with "CLOCK.GRF"
End ''Main
Routine CLOCK.UPDATE
given .TIME.ATR yielding .NEW.TIME.ATR
Define .TIME.ATR, .NEW.TIME.ATR as double variables
Let CLOCKTIME = .TIME.ATR
Let .NEW.TIME.ATR = .TIME.ATR
End ''CLOCK.UPDATE
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50. This page is intentionally blank
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

51. Exercise 6 The Pacific Port Problem (revisited)
C:\Program Files\Simscript3\models\ProblemC
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

52. Pacific Port Problem Revisited
Now that the prototype simulation model is working, the Harbor Master has requested a better estimate of the port performance. In order to satisfy this requirement, the following statistics have been requested:
1. Average and maximum waiting line for the docks
2. Average and maximum waiting line for the tugs
3. Utilization of the docks and the tug
4. Average and maximum ship waiting time (excluding unloading time)
5. Average and maximum in-port time for all ships
6. The number of ships served
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

53. Pacific Port Problem Revisited
In addition, consider a shipper who wishes to ship crude oil from Valdez, Alaska, to San Pedro. He estimates that shipments will require five ships of a particular type. The time to unload one of the new ships follows an exponential distribution with a mean of 21 hours. After unloading, the new ship will travel to Valdez, load more crude oil, and return to San Pedro. The round trip times follow a normal distribution with a mean of 10 days and a standard deviation of 1 day.
Before the port authorities agree to accommodate the five new ships, they want to determine the effect of the additional port traffic, especially on in-port residency time.
The Harbor Master also desires to see a graphical presentation of a histogram for number of ships versus WAITING.TIME in hours.
SELECT PROBLEMC (Or ANSWERB)
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

54. NOTES
To identify the new ships and the old ships, give the ships attributes such as:
EVERY SHIP has
a SHIP.TYPE
Define ..OLD.SHIP to mean 1
Define ..NEW.SHIP to mean 2
Activate a SHIP now
Let SHIP.TYPE(SHIP) = ..OLD.SHIP
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

55. NOTES: Calling a Synchronous Routine from a Process
1 Process SHIP 2
3 Define .ARRIVAL.TIME,
UNLOAD.TIME and
PROBABILITY
6 as real variables 7
8 Let .PROBABILITY = random.f(2)
9 Select case .PROBABILITY
Case 0.0 to .25
Let .UNLOAD.TIME = uniform.f(16.0, 20.0, 3)
Case .25 to .80
Let .UNLOAD.TIME = uniform.f(21.0, 27.0, 3)
Default
Let .UNLOAD.TIME = uniform.f(32.0, 40.0, 3)
Endselect ''.PROBABILITY 17
Call HARBOR.OPERATIONS
giving .UNLOAD.TIME
End ‘’SHIP
Routine HARBOR.OPERATIONS
Define .ARRIVAL.TIME,
.UNLOAD.TIME
as real variables
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————

56. 18 Let .ARRIVAL.TIME = time.v 19 20 Request 1 DOCK(1)
Request 1 TUG(1)
Wait 1.0 hour
Relinquish 1 TUG(1) 24
Work .UNLOAD.TIME hours 26
Request 1 TUG(1)
Wait 1.0 hour
Relinquish 1 TUG(1)
Relinquish 1 DOCK(1) 31
Let WAITING.TIME = (time.v - .ARRIVAL.TIME) * hours.v - .UNLOAD.TIME
Add WAITING.TIME to SUM.SHIP.DELAY
Let MAX.SHIP.DELAY = max.f(WAITING.TIME, MAX.SHIP.DELAY)
Add 1 to NO.OF.SHIPS.SERVED 36
37 End ''HARBOR.OPERATIONS
—————————— CACI Products Company ——————————————————————————————— SimScript II.5 ——————————————