Class Notes: 2/15/06

Note Takers: Catherine & Thomas

·         What did we do last time?

o       Presentation – by Sara

§         Same food, different portions

§         Rice differentiation

§         Nicole +1

§         Americans eat more than Korea

§         Chicken Sandwich – Spicy à hot

·         Today’s Presentation

o       Akron

Today

CPM (Critical Path Method)

PERT (Program Evaluation Review Technique) - Lance +1

What to do with these two above? To finish project in a good timely/costly fashion by lowering the cost.

Job can be done simultaneously - Lisa +1

CPM

• Good to know CPM and beneficial
• Do on time & do @ lower cost possible

PERT

Class Assignment:

• Project # 2: Use the Critical Path Method to complete a project. Find the critical path. Make up your own project. Use example from book (handouts pg. 54 and pg. 57). PERT will be extra credit.

• Handouts will be given

• MAKE IT YOUR OWN WITHOUT COPYING - SHOW YOU HAD LEARNED - SITE YOUR SOURCES AS WELL

• PERT - Extra Credit

• Demo it --> 5 pts - Good experience from a student and got an "A"

• NO DUE DATE

Internet References (Google search: “critical path method”):

            http://www.netmba.com/operations/project/cpm/

    http://hadm.sph.sc.edu/COURSES/J716/CPM/CPM.html

    http://www.buildersnet.org/cpmtutor/cpmtutor.html

CPM: 4 words: ES (Early Start), EF (Early Finish), LS (Late Start), LF (Late Finish).

E stands for Early

Early means how early you can start, finish

EF=early finish - Tahidul +1

What does L mean? Late

S means start.

F means finish.

What's the earliest you can start?

What's the latest you can finish?

• Node represents an activity

Every node/activity has ES, EF, LS, and LF.

Every node/activity has a completion time.

Immediate predecessor: activities that must be completed before node/activity can start.

Every node can have one before it? Predecessor - Steve +1

• Can't start B without A.

2 ways to do CPM:

Forward Pass – start from beginning and compute ES and EF. Backward Pass – start from end and compute LS and LF.

CMP works with a fixed time. Ex. Go to mechanic for 50,000 mile tune-up (they know when the parts need to be replaced).

• Know how much it takes - approximate time

Slack – allowable delay. If slack is 0 (zero), it’s in the critical path, any delay will delay whole project.

• Can't compromise with these nodes

• Learned about slack and compromise

• Compromise means:

Compute Slack: 2 ways

LS - ES and LF - EF (result of backward pass minus forward pass). If result is 0, it’s in the critical path.

What is the latest and earliest start?

Each Node:

Name of the node, duration that it takes, ES, EF, LS, LF, Slack

Finding ES (forward pass):

            ES = Max(EF of all immediate predecessors)

• Look @ maximum of EF - all immediate predecessor

• How to find ES - Go to that node & look for the earliest finished

• What's the earliest start for each node? Find out when they finish the node before & find the maximum.

EF of each node is calculated within the node itself.

Finding LF (backward pass):

            LF = Min(LS of all immediate predecessors)

• Mistake in the book about this - student brought it up

• What's the latest i can finish? Look @ latest start and look at minimum of it.

Summary

For every node, find earliest start and latest finish.

Critical Path = 0

Find a way to remember it!!!

____________________________________________________________________________________

Director of TLC - Professor Ebrahimi

• Project

• April 28th, Mid-April

Why changed it this year? Good Friday

• Now Professor Ebrahimi will show everything on April 28th.

• Professor Ebrahimi plans via memory

Time Slot Example: Delta

Nicole - Previous question +1

                    ________________________

Three you should know

1. Uniqueness/Quality Differentiation

2. Low Cost

3. Response - Ralph & Scott +1

                        __________________

From pg. 57 in book:

1st Row - Node

3rd Row - Time

How many weeks to build this unit? 25

• Good Operation Manager will finish it earlier - maybe 15

  • No compromising quality

Done in 6 steps:

       1 – Define Project

2 – Predecessor Table

3 – Time Table

4 – Network Diagram

5 – Forward Pass (calculate ES and EF – “the earlier you finish, the sooner I’ll start”).

• Start from beginning to end

• Goes with early start, EF

6 – Backward Pass (calculate LS and LF)

• Late start, late finish

7 – Critical Path and Slack

5 & 6 are hardest

Examples:

• Restaurant of a basketball player - Shaq -- Story of Professor Ebrahimi
  • Order his name - became a fan

Finished @ 9:42 PM