The Campus Wedding

DSM Description
In order to solve the Campus Wedding Case Study, the Critical Path Method network-planning model was used. The Critical Path Method is a procedure for scheduling a project in which activity times are known so single time estimates are used. The critical path of activities is the sequence of activities in the project that form the longest chain in terms of their time to complete. This means that if one of the activities on that critical path is delayed, then the whole project is delayed. There are four main steps to the Critical Path Method. The first step is to identify each activity to be done in the project and estimate how long it will take to complete each activity. The activities are usually labeled A, B, C, D, etc. each letter will have a number next to it representing the amount of time the activity will take, usually labeled in days or weeks.

The second step is to determine the required sequence of activities and construct a network reflecting the precedence relationships. To do this, it is best to first find the immediate predecessors, which are the activities that need to be completed immediately before the next activity. The predecessors are used to draw the network diagram. Once the diagram is drawn, the next step is to determine the critical path, which is the path where the sum of the activity times is the longest. The final step is to determine the early start/finish and late start/finish schedule for each activity. Slack time may occur when there is some leeway in the start and finish time. The early start and early finish times are written on the upper left and upper right corners respectively of the activity nodes in the diagram. These are the earliest possible times that the activity can start and finish. The late start and late finish times are written on the lower left and upper right corners respectively of the nodes. To calculate the early times, start with the first activity and work to the last one. To calculate the late times, start with the last activity and work back to the first.

Chart of Events
Based on the reading from the case, these are the activities that need to be completed before the wedding. The chart below indicates the activity, the letter used to label that activity, the number of days the activity will take to be completed, and finally the cost of crashing the activity if necessary.

| Activity| Days| Crashing Charges|
A| Church Booking| 1| |
B| Church Notice| 17| 10 days for $100|
C| Church Dec.| 3| |
D| Maid of Honor| 10| 2 days for $500|
E| Choose Cake| 2| |
F| Catering| 10| |
G| Receive Dress Lace| 8| 5 days for $25|
H| Dress Pattern| 3| |
I| Sew Dress| 11| 6 days @ 120 per day|
J| Dress Fitting| 2| |
K| Clean/Press Dress| 2| 1 day for $30|
L| Order Invitations| 12| 5 days for $35|
M| Choose Invitation| 3| |
N| Invitation Lead Time| 10| |
O| Mail Invitations| 1| |
P| Addressing Invitations | 4| 2 days @ $25 per day|
Q| Gifts| 1| |
R| Make Guest List| 4| |
S| Rehearsal Dinner| 1| |

Critical Path Network

Calculations
The Critical Paths
-Seven paths are created in the above critical path network. They are:
1) Path A-B-C21 Days
2) Path E-F-S13 Days
3) Path Q-S2 Days
4) Path D-J-K14 Days
5) Path H-G-I-J-K26 Days
6) Path M-L-P-O-N30 Days
7) Path R-P-O-N19 Days
-When the late start/early finish is completed to find the critical path, we find that path #6 to be the critical path for this particular case. However, since the wedding needs to be completed in 21 days and path #6 is at 30 days, this path will need to be crashed. Therefore, paths #1, 2, 3, 4, and 7 are the critical paths because they are at 21 days or less and can be completed in the allotted time before the wedding.

Crashing
– In order to finish all the activities on time, paths #5 and 6 need to be crashed since they both take longer than 21 days. – Path #5 – Total of 26 days – Needs to be reduced by 5 days
-Activities that can be crashed
G – Can be reduced by 3 days for a cost of $25
I – Can be reduced by 5 days for a cost of $120 per day
K – Can be reduced by 1 day for a cost of $30
-Solution
– Crash G(3 Days)$25
– Crash K(1 Day)$30
– Crash I(1 Day)$120
(5 Days)$175

-Path #6 – Total of 30 days – Needs to be reduced by 9 days
-Activities that can be crashed
L – Can be reduced by 7 days for a cost of $35
P – Can be reduced by 2 days for a cost of $50

-Solution
– Crash L(7 Day)$35
– Crash P(2 Day)$50
(9 Days)$85

Part B Solutions

The second part of this case describes a number of complications that arose in the days prior to the wedding.

1) On April 1, the chairman of the Vestry Committee at the church was left unimpressed by the added donation and said he wouldn’t reduce the notice period from 17 to 10 days. -This particular issue refers to item B in the critical path network, which falls on path #1. Since this path included the notice period of 17 days and takes 21 days to complete, the fact that reserving the church can not be crashed from 17 days to 10 days does not affect the wedding from being completed on time. 2) A call to Guatemala reveled that the potential bridesmaid had several commitments and could not possibly leave the country until April 10.

– Having the maid of honor travel to the wedding location refers to item D which is part of path #4. This issue would mean that the maid of honor would not arrive until April 20th, the day before the wedding and there are still four days worth of activates to complete after she arrives. The only solution would be to crash this particular item and have the maid of honor flown up which would have her arrive on April 12. However, this has to be done at a cost of $500. 3) Mother came down with the four-day flu just as she started on the guest list.

– Creating the guest list is item R on Path #7. This path is already at 19 days and a four-day setback due to the flu would put this path at 23 days, 2 days over what it needs to be in order to be done by the wedding. Since any items on this path that can be crashed have already been crashed, there is nothing else that can be done. The family must find another alternative, such as putting another person in charge of creating the guest list, if they want to meet their deadline. 4) The lace and dress materials were lost in transit. Notice of the loss was delivered to the Jackson home early on April 10th.

– The shipment of the lace and dress materials refers to item G which is part of path #5, a path that has already been crashed to make sure the everything that will be completed on time. As of April 10th, when the family receives the notice, there are only 10 days left until the wedding and 15 days of activities that need to be completed once the lace arrives. The only option the family has left is to hire Mrs. Watson to help sew for an additional 5 days at a cost of $500. This reduces the number of days from 15 to 10, but in order to complete everything before the wedding the lace would have to arrive the next day on April 11th. If it doesn’t, the family will not be able to complete everything on time before the wedding. 5) There was a small fire at the caterer’s shop on April 8. It was estimated that the shop would be closed two or three days for repairs.

– This issue will have no effect on the wedding. The items that refer to the caterer are on path #2, which is only at 13 days. An additional 2 or 3 day setback will still allow all these items to be completed on time.