Project Crashing

Warning Concerning Copyright Restrictions

The copyright law of the United States (Title 17, United States Code) governs the reproduction of copyrighted material.

Under certain conditions specified in the law, libraries and archives are permitted to furnish a reproduction if used for “private study, scholarship or research.” A second condition is that only single articles or chapters of a work totaling no more than 15% of the total number of pages be reproduced. Any use of a reproduction that exceeds these guidelines may be considered copyright infringement.

This institution reserves the right to refuse any request for reproduction that is deemed a violation of current copyright guidelines.

This material has been reproduced from the following source:

Date prepared:

This material is presented for use solely by authorized faculty and students of the Pennsylvania State University. Further reproduction or distribution of this material is expressly prohibited.

This material may be made available in alternative media upon request. Please contact Course Reserves Services at [email protected] or by phone at (814) 863-0324.

If you are experiencing problems viewing or printing this document, please visit http://www.libraries.psu.edu/psul/reserves/usingereserves.html for troubleshooting information. If further assistance is required, please send a description of the problem to [email protected] that includes the course and instructor for which the material is on reserve, as well as the title of the material.

PROBLEMS

7. Explain the difference in the problems faced by a PM who is short of secretarial resources and one who is short .of a "Walt."

8. When allOcating scarce resources to several differ- ent projects at the same time, why is it important to make sure that all resource calendars are on the same time base (i.e., hourly, daily, weekly ... )?

DISCUSSION QUESTIONS

12. Describe the fundamental trade-offs made when deciding whether or not to crash a project. If the decision is made to crash, what additional trade~offs must be made?

13. Discuss the advantages of "labor poolsu in a project~ oriented company, Are there any potential disad~ vantages with the use of pools?

14, What purpose(s) might be served by using each of the following priority rules for allocating scarce resources?

a. As late as possible

b. Shortest task duration time first

c. Minimum slack first

15. Linking a group of projects together with pseudoac~ tivities creates a sort of superproject. What does th_is mean1 and why would anyone want to do it?

16. Describe in your own words what is meant by Goldratt's critical chain. How does it work?

PROBLEMS

20. Given the following project to landscape a new building site:

Activity Immediate Duration Resource

Activity Predecessor (days) Used

A - 2 X,Y

B A 2 X

C A 3 X

D B,C 4 X, y

E D 3 w,x F D 1 W,X,Y

G E,F 2 X, y

(a) Draw a Gantt chart using MSP.

(b) Assuming a 5-day week, find the critical path and project duration in days.

• 237

9. List.and describe the three most common criteria by which to evaluate different resource allocation prior- ity rules.

10. "Why is the problem of allocating scarce resources to a set of projects similar to the problem of scheduling a job shop?

11. What is meant by the term "student syndromen?

17. Projects A and B are both nearing completion. You are managing a super important project C that requires an immediate input of a resource being used by both proj·ects A and B, but is oth~ erwise unavailable. Project A has a Type 1 life cycle. Project B's life cycle is Type 2. From which ( or both or neither) do you borrow the resource? Why?

18. Goldratt suggested that to avoid the "student syn~ drome,1' it is a good idea to set activity durations so short that there is a high probability that the task will not be finished on time. On the other hand, it has long been known that setting people up for failure is strongly demotivating. What should the PM do?

19. Describe as many types of resource allocation prob~ lems as you can, based on the situations described in the chapter.

(c) Given that each resource is assigned 100 percent to each task, identify the resource constraints.

(d) Using the MSP default, level the resources and determine the new project duration and critical path.

(e) Identify what alternative solutions can be used to shorten the project duration without overal~ locating the resources,

21. Given the following project (all times are in days):

Acti~ Prede- Normal Normal Crash Crash vity cessor Time Cost Time Cost

a 5 $50 3 $150 b 4 40 2 200 C b 7 70 6 160 d a,c 2 20 1 50 e a, C 3 30 f b 8 80 5 290 g d 5 50 4 100 h e, f 6 60 3 180

238 • CHAPTER 6 / ALLOCATING RESOURCES TO THE PROJECT

22.

(a) Draw the network (AOA or AON) and find the critical path, time, and cost for an all-normal level of project activity.

(b) Calculate the crash cost-per-day (all activities may be partially crashed).

(c) Find the optimal way of getting an 18-day deliv- ery time, What is the project cost?

(cl) Find the optimal way of getting a 16-day deliv- ery time. What is the project cost?

(e) Calculate the shortest delivery time for the project. What is the cost?

Given the following AOA network, determine the first activity to be given extra resources by the fol- lowing priority rules:

(a) Shortest task first

(b) Minimum slack first

(c) Most critical followers

(d) Most successors

23. Given the project shown in Figure 5-10 of Chapter 5, assume that a facility used by activities c and d is scarce. To which activity would you assign the facil- ity first, given the following rules:

(a) Minimum slack rule

(b) Most followers

(c) Most critical followers

(cl) Shortest task first

(e) As late as possible

24. Consider the following activity information and the constraint that the project must be completed in 16 weeks.

INCIDENTS FOR DISCUSSION

Lab Results, Inc.

Sam G. Farshe runs a medical laboratory in Pittsburgh. He has contracts with several doctors' offices to con- duct their lab work. He runs the lab tests and report,s the results on their patients. Lab Results, Inc. has a reputa- tion of always delivering quality results within the time specifications of each contract. Sam is pleased with his companis results. His crew of technicians works hard. He prides himself on the fact that there is no excess capac-

25.

Activity

A B C D E F G H I

Duration (weeks)

3 6 8 7 5 10 4 5 6

Preceding Activity

A B C C

D,E,F G

In addition, activity C may be crashed to 7 weeks at a cost of $40, activity F may be crashed to 6 weeks at a cost of $20/week, activity H may be crashed to 2 weeks at a cost of $10/week, and activity I may be crashed to 3 weeks at a cost of $30/week. Find the best schedule and cost.

Consider the project network below. Suppose the duration of both activities A and D can be reduced to 1 day, at a cost of $15 per day of reduction. Also, activities E, Gi and H can be reduced in duration by 1 day, at a cost of $25 per day of reduction. What is the least-cost approach to crash the project by 2 days? \X'hat is the shortest "crashed" duration, the new critical path, and the cost of crashing?

Start

Cl~

~~ ~

~~

ity in his operation. He pays overtime to his technicians weekly, but always includes those costs in his contracts.

Sam has been asked to bid on a contract to do the lab work for an area hospital whose lab is being renovated. The hospital needs to outsource their lab services tempo- rarily. They estimate construction will take 2-3 months, and they want a free-standing lab service to cover their needs for 4 months; then the hospital will resume the service. Sam is treating this as a project and intends to