Uploaded by Jeremy Bernard

AP4

advertisement
AP4: Queuing
OPS 3880
Jeremy Bernard
Time to refresh. You mosey over to your favorite place but with a history of a line. Usually,
you can expect there to be 20 people in line any time you come here (there is only one order
taker). Service time averages 20 seconds. SHOW ALL WORK!
1
1
Remembering 𝜌 = πœ‡πœ† , 𝐿 = πœ†π‘Š, π‘Š = πœ‡−πœ†
, πΏπ‘ž = 𝜌𝐿 = 𝐿 − 𝜌, π‘Šπ‘ž = πœŒπ‘Š = π‘Š − , 𝑃𝑛 = (1 − 𝜌)πœŒπ‘›
πœ‡
a. What is the utilization of the server? ___71.43__%
The utilization of the server is the percentage of time that the server is busy..
π‘ˆπ‘‘π‘–π‘™π‘–π‘§π‘Žπ‘‘π‘–π‘œπ‘› = π΄π‘£π‘’π‘Ÿπ‘Žπ‘”π‘’ π΄π‘Ÿπ‘Ÿπ‘–π‘£π‘Žπ‘™ π‘…π‘Žπ‘‘π‘’ / π΄π‘£π‘’π‘Ÿπ‘Žπ‘”π‘’ π‘†π‘’π‘Ÿπ‘£π‘–π‘π‘’ π‘…π‘Žπ‘‘π‘’
= 7 / 20
= 0.357143
= 71.43%
b. What is the expected time between people arriving to this system? __8.57143 __
seconds
π΄π‘£π‘’π‘Ÿπ‘Žπ‘”π‘’ π΄π‘Ÿπ‘Ÿπ‘–π‘£π‘Žπ‘™ π‘…π‘Žπ‘‘π‘’ = 7 π‘π‘’π‘œπ‘π‘™π‘’ / π‘šπ‘–π‘›π‘’π‘‘π‘’
= 7 / 60 π‘ π‘’π‘π‘œπ‘›π‘‘π‘ 
= 0.116667 π‘π‘’π‘œπ‘π‘™π‘’ / π‘ π‘’π‘π‘œπ‘›π‘‘
𝐸π‘₯𝑝𝑒𝑐𝑑𝑒𝑑 π‘‡π‘–π‘šπ‘’ 𝐡𝑒𝑑𝑀𝑒𝑒𝑛 π΄π‘Ÿπ‘Ÿπ‘–π‘£π‘Žπ‘™π‘  = 1 / π΄π‘£π‘’π‘Ÿπ‘Žπ‘”π‘’ π΄π‘Ÿπ‘Ÿπ‘–π‘£π‘Žπ‘™ π‘…π‘Žπ‘‘π‘’
= 1 / 0.116667 π‘ π‘’π‘π‘œπ‘›π‘‘π‘ 
= 8.57143 π‘ π‘’π‘π‘œπ‘›π‘‘π‘ 
c. What is the expected wait until service starts? __14.2857 ___ seconds
The expected wait time is the average amount of time that a customer has to wait
before being served.
𝐸π‘₯𝑝𝑒𝑐𝑑𝑒𝑑 π‘Šπ‘Žπ‘–π‘‘ π‘‡π‘–π‘šπ‘’ = π‘ˆπ‘‘π‘–π‘™π‘–π‘§π‘Žπ‘‘π‘–π‘œπ‘› ∗ π΄π‘£π‘’π‘Ÿπ‘Žπ‘”π‘’ π‘†π‘’π‘Ÿπ‘£π‘–π‘π‘’ π‘‡π‘–π‘šπ‘’
= 0.714286 ∗ 20 π‘ π‘’π‘π‘œπ‘›π‘‘π‘ 
= 14.2857 π‘ π‘’π‘π‘œπ‘›π‘‘π‘ 
d. What is the probability of 3 or fewer people in line upon your arrival? _92.86___%
π‘ƒπ‘Ÿπ‘œπ‘π‘Žπ‘π‘–π‘™π‘–π‘‘π‘¦ π‘œπ‘“ 3 π‘œπ‘Ÿ πΉπ‘’π‘€π‘’π‘Ÿ π‘ƒπ‘’π‘œπ‘π‘™π‘’ 𝑖𝑛 𝐿𝑖𝑛𝑒 = (1 − π‘ˆπ‘‘π‘–π‘™π‘–π‘§π‘Žπ‘‘π‘–π‘œπ‘›)^3
= (1 − 0.714286)^3
AP4: Queuing
OPS 3880
= 0.9286
= 92.86%
Jeremy Bernard
Download