Conceptual
If batch size increases, what happens to capacity with a setup time?
What is Capacity increases?
Scenario:
t1: 15s t2: 15s t3: 10s t4: 35s t5:5s t6:40s
What is the capacity of the above process in hours?
90 units per hour
What unit(s) are activity times measures in?
What is time per unit?
How much slack can any node on the critical path have?
What is 0?
Little's Law is...?
What is Avg. Inventory = Avg. Flowrate x Avg. Flowtime?
In a Project network the critical path could most recently compared to what earlier concept?
What is Bottleneck?
** Flow rate min( demand rate, maximum capacity)
** max capacity = bottleneck
Consider a bakery with 3 stations. Station 1 is mixing batter for 5 min (with 3 employees), station 2 is baking for 10 min (with 1 employee), and station 3 is packaging the loaves of bread 5 min (with 2 employees). Find the labor utilization of this process, if a loave of bread comes out every 10 minutes
What is 33.33%?
Assume there is one Elevator in a The Downtown building, "49th Manhattan's Garden Grove," in New York City. The residence building is extremely exclusive, so the maximum capacity is 15 people. Loading and unloading takes 1s per person, and it takes 60 s to reach up to the residence floor, and 40 sec to get back down.
The flowrate is 1 every 15 sec, or 240 per hour
What would be the Average time between a resident arriving to the building, and them going up to their actual floor, if the average inventory was 25 (in min)?
Average inventory = Average flowrate * Average Flowtime
25 = 240 * average flowtime
25/240 = .1041666 * 60 = 6.25 min
What is 6.25 min
What is the difference between the minimum possible project duration, and the shortest duration?
What is Minimum possible includes the crashes, but shortest duration is the critical path.
Capacity formula is...?
What is (batch size)/ ((batch size * activity time ) + setup time) ?
** note if there are additional workers you must:
# of workers * capacity
Break Even Volume increases when...
There are multiple answers, but when any ONE cost increases generally Break even volume increases.
Consider Blue Cross clinic. They have 3 stations and 1 employee each. Check up, doctor visit & evaluation, sign out. on average they take up 10 min, 20 min, 5 min.
Which step is the bottleneck, and what is the labor content?
What is Doctor visit, and 35 min?
Assume there is one Elevator in a The Downtown building, "49th Manhattan's Garden Grove," in New York City. The residence building is extremely exclusive, so the maximum capacity is 15 people. Loading and unloading takes 1s per person each, and it takes 60 s to reach up to the residence floor, and 40 sec to get back down.
The flowrate is 1 every 15 sec
How long is the elevator idle?
We know the process repeats itself every 255 sec, and we know the elevator is busy for the 60 sec traveling up, 40 sec traveling down, and 2 sec loading & unloading together
60+40+2*15 = 130 of busy time
(225-130)/ 225 = What is 42.22%
A project has 2 paths
ABDF
ACEF
A = 5; B = 3; C= 8; D = 5; E = 2; F = 5
If Node B = 5, which activities would be critical?
What is All activities would be critical?
Labor Utilization is...?
What is (labor content) / (Cycle time * number of employees)
** note number of employees may be different than number of steps
The three criteria to look for when crashing a node in a project are...
1. Which nodes are on all the critical paths
2. Of those nodes which one or which combination are the cheapest to crash
3. Crash & lower the path(s) with the crashed node(s) by 1 week.
Consider The Denny Douquette - Grey Sloan memorial Free clinic. They have 3 stations. Check up (2 nurses (Olivia, Issac)), doctor visit & evaluation (4 Residents (Meredith, Christina, Alex, Izzy)), sign out (1 administrative assist). on average they take up 10 min, 20 min, 5 min. If the flow rate is the bottleneck capacity, how long after opening (8 am) will the process 50 clients?
Rush order flow time is 35 min, Flow rate is bottleneck which is 1 patient every 5 min
35 + 49*5 = 280 min
280/60 = 4.66667 hrs
What is 12:40 pm?
Assume there is one Elevator in a The Downtown building, "49th Manhattan's Garden Grove," in New York City. The residence building is extremely exclusive, so the maximum capacity is 15 people. Loading and unloading takes 1s per person, and it takes 60 s to reach up to the residence floor, and 40 sec to get back down.
The flowrate is 1 every 15 sec
What is the average buffer inventory?
What is 15/2 = 7.5?
A project has 2 paths
ABDF
ACEF
Normal durations: A = 5; B = 3; C= 8; D = 5; E = 2; F = 5
Crashed Durations: A = 2 ($100 per week); B = 3; C = 8; D = 1 ($50 per week); E = 2; F = 4 ($10 per week)
What is the minimum possible duration, and the crash cost to get to that duration?
what is 14 Weeks, and $310?
Average Batch Size Formula is...?
[[Q(act. time of ride] + [(Q/2)*Q(Act. time of unloading per person)]]/(Q*Flowrate)
How do you find the number of weeks you can crash a project given Normal cost, crash cost, and weekly crash cost?
What is (Crash cost - Normal cost)/ weekly crash cost
An imitator of Benihana is opening up a dining area in Greenwhich conneticut. It plans a 60 seat dining room, and anticipates people to stay for 60 min, and they anticipate people to stay in the pre-ding area for 15 min.
If they want to balance the traffic between the dining area and pre-ding area, how many seats should the pre-dining area have?
We want the flow rates to be the same, so
60/60 = 15/15,
What is 15 seats?
Assume there is one Elevator in a The Downtown building, "49th Manhattan's Garden Grove," in New York City. The residence building is extremely exclusive, so the maximum capacity is 15 people. Loading and unloading takes 1s per person each, and it takes 60 s to reach up to the residence floor, and 40 sec to get back down.
The flowrate is 1 every 15 sec
What is the average batch inventory?
([(15)*60] + [.5(15) * 1(15)])/(15*15)
what is 4.5 people?
A project has 2 paths
ABDF
ACEF
A = 5; B = 3; C= 8; D = 5; E = 2; F = 5
Find the Critical Paths, and ES, EF, LS, LF, and Slack for each node
What is
A 0-5-0-5-0
B 5-8-7-10-2
C 5-13-5-13-0
D 8-13-10-15-2
E 13-15-13-15-0
F 15-20-15-20-0
ACEF = 20 ?
What is the relationship between Flow rate, Cycle Time, capacity, and activity time?
What is Flow rate min (process capacity, demand rate) and 1 / cycle time; 1/ activity time = capacity?