1. What do the sequencing rules SPT, DDATE, and SLACK mean?
SPT - shortest processing time
DDATE - earliest due date
SLACK - difference between due date and remaining processing time
2. What is the advantage of the SPT rule? Of the DDATE rule?
SPT minimizes the average flow time and is a good rule when a shop is congested; DDATE minimizes lateness and is a good rule when customers are demanding.
3. Define critical path.
The critical path is the path with the longest duration in the network. The project cannot be completed in less than the time of the critical path.
4. How is the earliest start time for an activity calculated? The latest finish time?
Forward pass starts at the beginning to determine the earliest start time. Backward pass starts at the end of the network to determine latest finish time.
5. According to Garvin, what are at least 8 different types of design quality?
reliability, durability, conformance, aesthetics, features, serviceability, perceptions, safety, performance
6. What are four types of quality costs? Give examples of each.
prevention - design reviews
appraisal - in-process inspections
internal failures - rework before leaving the plant
external failures - customer returns for defects
7. Who is the most well-known quality "guru" whose ideas got major exposure in Japan?
Deming
8. What are the seven tools of continuous improvement?
Flowcharts, check sheets, Pareto analysis, fishbone (cause-and-effect) diagrams, scatter diagrams, SPC charts, histograms
9. What are two types of breakthrough improvement?
bench-marking and re-engineering
10. For what purposes are control charts used?
knowing when to adjust a process, knowing when to leave a process alone, and checking process capability to see if it tolerances can be met
11. If acceptance sampling is used, what happens if the number of defects found in a sample exceeds the allowable number of defects?
Reject the whole lot
12. Give an example of an attribute measurement and a variable measurement.
attribute measurement - # of errors typing
variable measurement - inches in diameter
13. Give an example of a single-channel, single phase service system, a single-channel, multiple-phase service system, and a multiple-channel, single-phase service system.
Single-channel single-phase - grocery store check-out
Single-channel, multiple phase - McDonald's drive-thru
Multiple-channel, single-phase - airline check-in
14. What are the assumptions of the basic mathematical queuing models? Why must the arrival rate be less than the service rate?
Poisson arrival rate
exponential service times
first-come, first-served queue discipline
infinite queue length
infinite calling population
Arrival rate (a) must be less than service rate (average) or the system never clears out.
15. Define critical path.
.Critical path is the path with the longest time. It defines the project completion schedule
16. How is the earliest start time for an activity calculated? The latest finish time?
The earliest start time is equal to the largest earliest finish time of all its predecessors. The latest finish time is equal to the latest start time of all its successors.