R. C. Coleman

Case Study: R. C. Coleman

Shripal Shah Case Study #2 R. C. COLEMAN Prof. Marian Reiff University of Redlands, Riverside Campus

Case Study: R. C. Coleman The Critical Path is: B-C-E-F-H-J-K The EXPECTED PROJECT COMPLETION TIME = 43 weeks The Variance of Critical path = 2.778 + 0.444 + 1.00 + 0.444 + 0.444 + 0.111 + 0.444 = 5.67 From the standard normal distribution table: Area of probability = 0.3962 P (t < 40) = 0.5 – 0.3962 = 0.1038 From the calculations above, there is about 10.38% chance for R.C Coleman to complete the project in 40 weeks or less. Recommendation: In case 40-week completion required, R.C. Coleman should consider crashing project activities. 2. From the standard normal distribution table, for 80% chance: z = 0.84 Also, z = 40-t5.67 = 0.84 * t = 38 weeks R.C Coleman should crash activities to reduce the expected completion time to 38 weeks , shorten by 2 weeks. 3. Using the expected activity times as the normal times to determine the crashing activity decision Let

xi = the completion time for activity i

yi = the amount of crash time for activity i Min 450yA + 400yB + 600yC + 300yD + 1000yE + 550yF + 750yG + 700yH + 800yI + 400yJ + 500 s.t xA + yA > 6 xB + yB > 9 xC + yC – xA > 4 xC + yC – xB > 4 xD + yD – xC > 12 xE + yE – xC > 10

Case Study: R. C. Coleman xF + yF – xE > 6 xG + yG – xC > 8 xH + yH – xF > 6 xH + yH – xG > 6 xI + yI – xD > 7 xI + yI – xF > 7 xJ + yJ – xH > 4 xK + yK – xI > 4 xK + yK – xJ > 4 xK < 38 yA < 2 yB < 2 yC < 2 yD < 4 yE < 3 yF < 2 yG < 3 yH < 2 yI < 3 yJ < 1 yK < 1 All xi,yi > 0

Case Study: R. C. Coleman Minimum-cost crashing solution Optimal crashing decisions are as follows: Activity| Time in weeks | crash | Cost | A

|6

|0

|-

|

B

|7

|2

| 800

|

C

|4

|0

|-

|

D

| 12

|0

|-

|

E

| 10

|0

|-

|

F

|5

|1

| 550

|

G

|8

|0

|-

|

H

|6

|0

|-

|

I

|7

|0

|-

|

J

|3

|1

| 400

|

K

|3

|1

| 500

|

| Total |

| 2250 |

The additional cost for a project goal of 40 weeks is $1200 The additional cost for a project goal of 38 weeks is $2250 A revised activity schedule based on these crashing decisions is attached.