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31 Cards in this Set
- Front
- Back
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What is scheduling?
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Establishing the timing of the
use of equipment, facilities and human activities in an organization |
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Effective scheduling can yield
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Cost savings
Increases in productivity |
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What is Loading
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assignment of jobs to process
centers |
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What is Sequencing
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determining the order in
which jobs will be processed |
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What is Job-shop scheduling
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Scheduling for low-volume
systems with many variations in requirements |
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What is a Gantt chart
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used as a visual aid for
loading and scheduling |
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Name the types of Loading
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infinite loading
finite loading forward scheduling backward scheduling |
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What is Infinite loading and list the three aspects of it..
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A work center is assigned
work based on what is needed over time. Work center Capacity is ignored Sequencing of jobs is ignored Lead time is estimated. |
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What is Finite loading
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Schedules in detail each
resource using setup and run time required for each order (job) What will be done by each resource at every moment during a working day. |
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what is forward scheduling and name places it's used in.
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Forward scheduling starts the schedule as
soon as the requirements are known. used in make to order systems: hospitals, restaurants, manufacturing, … |
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what is backward scheduling and name places it's used in.
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Backward scheduling begins with a given
due date of a certain job, starting with the final step and scheduling the steps of the job, in time, in reverse order. Manufacturing, service operations |
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Typical Scheduling and Control
Functions |
Allocating orders, equipment, and personnel
Short-term capacity planning Determining the sequence of order performance Prioritizing orders/jobs Initiating performance of the scheduled work Dispatching orders/ jobs release Shop-floor control Review/control of in-progress orders Expediting late orders and rushed orders |
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Work-Center Scheduling Objectives (name 5)
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Meet due dates
Minimize lead time Minimize setup time or cost Minimize work-in-process inventory Maximize machine utilization |
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Schedule Performance Measures
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Meeting due dates of customers or
downstream operations. Minimizing the flow time (the time a job spends in the process) Minimizing work-in-process inventory. Minimizing idle time of machines or workers. |
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Sequencing:
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Determine the order in which
jobs at a work center will be processed |
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Workstation:
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An area where one person
works, usually with special equipment, on a specialized job. |
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Priority rules:
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Job time:
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Time needed for
setup and processing of a job. |
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Priority Rules (5)
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Simple heuristics
used to select the order in which jobs will be processed. 1. First-Come, First-Served (FCFS) 2. Shortest Processing Time (SPT) 3. Earliest Due Date first (EDD) 4 Earliest start date first -Start date = Due date - Lead time 5. Least Slack Time Remaining first (STR) - STR = Time Remaining - Processing Time Remaining |
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Sequencing n Jobs on Two Work Center (3 points)
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Johnson’s Rule:
Minimizes total idle time Several conditions must be satisfied |
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What's Johnson's rule
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technique for minimizing
completion time for a group of jobs to be processed on two |
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Johnson’s Rule Conditions
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Job time must be known and constant
Job times must be independent of sequence Jobs must follow same two-step sequence Job priorities cannot be used All units must be completed at the first work center before moving to second |
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Steps to Johnson's rule
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1. List the operation time for each job on
both work centers. 2. Select the shortest operation time. 3. If the shortest time is for the first work center, we do the job first; if it is for the second work center, do the job last. 4. Repeat Steps 2 and 3 for each remaining job until the schedule is complete. |
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For Scheduling Service Operations,
define: Appointment systems |
Controls customer arrivals for service
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For Scheduling Service Operations,
define: Scheduling the workforce |
Manages capacity for service
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For Scheduling Service Operations,
define: Reservation systems |
Estimates demand for service
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For Scheduling Service Operations,
define: Scheduling multiple resources |
Coordinates use of more than
one resource |
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Name places that use the "Cyclical Scheduling"
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Hospitals, police/fire departments,
restaurants, supermarkets |
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Describe Rotating schedules
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Set a scheduling horizon
Identify the work pattern Develop a basic employee schedule Assign employees to the schedule |
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Name Service Operation Problems
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Cannot store or inventory services
Customer service requests are random |
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Scheduling service involves which 3 components?
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- Customers
-Workforce - Equipment |
