The receiving yard
One arrival rate, one operating choice, and the wait seen from two seats.
This is a fictional case. Times use an 8 hour operating day. Queue results are steady state approximations, not a prediction of tomorrow's shift. The site and carrier share allocates waiting value for this case. It does not establish who can invoice whom.
1. The gate and the bay
A completed operating log records an average of 7.2 trucks inside the gate. Arrivals and departures match over the log. Unloading takes 24 minutes. Occupancy is a time average, not a count taken at one busy moment. The boundary runs from entry to exit and includes all time inside the gate.
Available facts
- Average trucks inside the gate7.20 trucks
- Operating day8 operating hours
- Measured unloading time24 minutes
Inputs and givens
Case range: 0 to 40 trucks per operating day. The rate must be greater than 0.
How many operating hours does a truck spend inside the gate on average?
Operating hours. Within 0.05 operating hours
Within 0.05 operating hours From 0 to 24.
The score is a target for this attempt. It is not a judgement of you.
Typing the model's own answer earns full marks.
A number within the stated tolerance earns 10 points. Beyond it, each further tolerance removes 1 point, down to 0.
How this check is calculated
Average occupancy divided by throughput gives time in the same boundary. L is average trucks, lambda is trucks per operating day and W is operating days. Multiplying by 8 converts that duration to operating hours. Unloading is one component of gate time.
Show the full maths
Symbols and assumptions
All rates, patterns, costs and band counts belong to this fictional case. The books explain the mechanisms and do not supply these data.
Check this step before continuing.
The receiving yard
One arrival rate, one operating choice, and the wait seen from two seats.
This is a fictional case. Times use an 8 hour operating day. Queue results are steady state approximations, not a prediction of tomorrow's shift. The site and carrier share allocates waiting value for this case. It does not establish who can invoice whom.
Journey incomplete
1. The gate and the bay
A completed operating log records an average of 7.2 trucks inside the gate. Arrivals and departures match over the log. Unloading takes 24 minutes. Occupancy is a time average, not a count taken at one busy moment. The boundary runs from entry to exit and includes all time inside the gate.
- Average trucks inside the gate7.20 trucks
- Operating day8 operating hours
- Measured unloading time24 minutes
Not checked in this attempt
- Arrivals per operating day18
How this check is calculated
Average occupancy divided by throughput gives time in the same boundary. L is average trucks, lambda is trucks per operating day and W is operating days. Multiplying by 8 converts that duration to operating hours. Unloading is one component of gate time.
Show the full maths
Symbols and assumptions
All rates, patterns, costs and band counts belong to this fictional case. The books explain the mechanisms and do not supply these data.
2. One more arrival
Not reached in this attempt
3. A shared second bay
Not reached in this attempt
4. Bookings and standard work
Not reached in this attempt
5. Each group gets a bay
Not reached in this attempt
6. The convoy policy
Not reached in this attempt
7. The trucks present now
Not reached in this attempt
Your yard decision record
Journey incomplete
Only checked steps appear in this account. Later events and unchecked answers are left out.
0 from 0 checked steps
Final possible total: 70 points
Checks in this attempt
| Step | Your answer | Model target | Points | Tolerance |
|---|
The score is a target for this attempt. It is not a judgement of you. Typing the model's own answer earns full marks.
A number within the stated tolerance earns 10 points. Beyond it, each further tolerance removes 1 point, down to 0.
Sources
Two books supply context for the mechanisms. All case quantities and costs are fictional.
- Wallace J. Hopp and Mark L. Spearman, Factory Physics, 3rd edition, McGraw Hill Irwin, 2008.
Variability and queue approximation
- Mor Harchol Balter, Performance Modeling and Design of Computer Systems: Queueing Theory in Action, Cambridge University Press, 2013.
Boundaries, shared servers and sampling