operations management final

critical path

• the longest path (from start to finish) through the network

• the shortest time in which the project can be completed

• any delay in activities in the critical path delays the projext

• critical paths have NO slack time

earliest start (ES)

earliest time at which an activity can start, assuming all predecessors have been completed

earliest finish (EF)

earliest time at which an activity can be finished

latest start (LS)

latest time at which an activity can start so no delays affect the completion time of the entire project

latest finish (LF)

latest time by which an activity has to be finished to not delay the completion time of the entire project

work breakdown structure

1. project

2. major tasks in the project

3. subtasks in the major tasks

4. activities (or “work packages”) to be completed

kanban

the japanese word for card

• the cart is an authorization for the next container of material to be produced

• a sequence of kansans pulls materials through the process

• many different sorts of signals are used, but the system is still called a kanban

weighted moving average

• used when trend is present (older data usually less important)

• weights based on intuition equation: sum of (weight for period n)(demand in period n)/sum weights

exponential smoothing method

• form of weighted moving average (weights decline exponentially with most recent data weighted most)

• requires smoothing constant (ranges from 0 to 1)

• involves little record keeping of past data