OPRE 6302 Assignment1
1. A manufacturer's average work-in-process inventory for a certain part is 1,000 units. The workstation produces this part at the rate of 200 units per day. What is the average time a unit spends at this workstation?
Ans:
Throughput R = 200 units/day
Average Inventory I = 1000 units
As per Little’s Law “average inventory equals the product of average throughput and average flow time”. I = RT
Average Flow Time T = I/R = 1000/200 = 5 days
On average a units spends 5 days at this workstation.
2. Assume that the system is operating at a steady state.
a) Draw a flow diagram for the entire process. Include flow paths for students (solid lines) and prescriptions (dashed lines).
Ans:
The above diagram shows the flow chart for the prescriptions Pharmacy process. Movement of prescription are shown in dotter line while movement of students are shown in thick line in the diagram.
b) What is the average time in the pharmacy for those students who stay to pick-up their Rxs?
Ans:
On average 2 prescriptions are coming to pharmacy i.e. 120 prescriptions per hour.
Total 40 prescriptions are either in process or waiting at Fill Rx state. Using Little’s Law inventory at Fill Rx state = (40/2) = 20min
If a student wants to wait for pickup of the prescription, then he/she has to wait for 20min. That will be the flow time of waiting student at Fill Rx state.
Using all the other information provided in the case, we can fill the below table using Little’s Law. Given information is shown in black color and calculated information is shown in blue color in the below table.
Drop-Off
Patients Waiting for Pick-Up
Pick-up
Cashier
Throughtput R = I/T
(No of Patients/Hr)
120
6
120
120
Flow Time T (min)
2.5
20.00
1.5
3
Inventory I
(No of Patients)
5
2
3
6
Total time on average a Student who waits to pick up prescription spends = 2.5+20+1.5+3 = 27min
c) What is the average time in the
Ans:
Throughput R = 200 units/day
Average Inventory I = 1000 units
As per Little’s Law “average inventory equals the product of average throughput and average flow time”. I = RT
Average Flow Time T = I/R = 1000/200 = 5 days
On average a units spends 5 days at this workstation.
2. Assume that the system is operating at a steady state.
a) Draw a flow diagram for the entire process. Include flow paths for students (solid lines) and prescriptions (dashed lines).
Ans:
The above diagram shows the flow chart for the prescriptions Pharmacy process. Movement of prescription are shown in dotter line while movement of students are shown in thick line in the diagram.
b) What is the average time in the pharmacy for those students who stay to pick-up their Rxs?
Ans:
On average 2 prescriptions are coming to pharmacy i.e. 120 prescriptions per hour.
Total 40 prescriptions are either in process or waiting at Fill Rx state. Using Little’s Law inventory at Fill Rx state = (40/2) = 20min
If a student wants to wait for pickup of the prescription, then he/she has to wait for 20min. That will be the flow time of waiting student at Fill Rx state.
Using all the other information provided in the case, we can fill the below table using Little’s Law. Given information is shown in black color and calculated information is shown in blue color in the below table.
Drop-Off
Patients Waiting for Pick-Up
Pick-up
Cashier
Throughtput R = I/T
(No of Patients/Hr)
120
6
120
120
Flow Time T (min)
2.5
20.00
1.5
3
Inventory I
(No of Patients)
5
2
3
6
Total time on average a Student who waits to pick up prescription spends = 2.5+20+1.5+3 = 27min
c) What is the average time in the