for aiub summar , for semister break preparation

1. Course: Operations Management
American International University-Bangladesh

2. SCHEDULINGSCHEDULING
 Scheduling is establishing the timing of the use of equipment,Scheduling is establishing the timing of the use of equipment,
facilities and human activities in an organizationfacilities and human activities in an organization

Effective scheduling can save cost and increase productivityEffective scheduling can save cost and increase productivity
• In educational institutions, scheduling can reduce the need for expansionIn educational institutions, scheduling can reduce the need for expansion
of facilitiesof facilities

Effective scheduling can give a company competitiveEffective scheduling can give a company competitive
advantageadvantage

The objectives of scheduling are to achieve trade - offs amongThe objectives of scheduling are to achieve trade - offs among
efficient utilization of staff, equipment and facilities, andefficient utilization of staff, equipment and facilities, and
minimization of customer waiting time, cost, inventories andminimization of customer waiting time, cost, inventories and
process timesprocess times
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3. SCHEDULING IN HIGH VOLUME SYSTEMSSCHEDULING IN HIGH VOLUME SYSTEMS
 Scheduling encompasses allocating workloads to specificScheduling encompasses allocating workloads to specific
work centers and determining the sequence in whichwork centers and determining the sequence in which
operations to be performedoperations to be performed
 High volume systems are characterized by standardizedHigh volume systems are characterized by standardized
equipment and activities that provide highly similarequipment and activities that provide highly similar
operationsoperations
 Automobiles, personal computers, toy, television etc.Automobiles, personal computers, toy, television etc.
 High volume system with standardized equipment andHigh volume system with standardized equipment and
activities is also known asactivities is also known as Flow SystemFlow System
 Scheduling for low volume systems with many variations inScheduling for low volume systems with many variations in
requirements is calledrequirements is called Job Shop SchedulingJob Shop Scheduling

4.  Process and product designProcess and product design -- Cost and manufacturability isCost and manufacturability is
important as well as achieving a smooth flow through the systemimportant as well as achieving a smooth flow through the system
 Preventive maintenancePreventive maintenance -- Keeping equipment in good operatingKeeping equipment in good operating
order can minimize breakdowns that would disrupt the flow of workorder can minimize breakdowns that would disrupt the flow of work
 Rapid repair when breakdown occursRapid repair when breakdown occurs -- This require specialistsThis require specialists
and stocks of spare partsand stocks of spare parts
 Optimal product mixesOptimal product mixes -- Optimal blends of inputs to achieveOptimal blends of inputs to achieve
desired outputs at minimal costdesired outputs at minimal cost
 Minimization of quality problemsMinimization of quality problems -- Quality problems can beQuality problems can be
extremely disruptive, requiring shutdowns while problems are resolvedextremely disruptive, requiring shutdowns while problems are resolved
 Reliability and timing of suppliesReliability and timing of supplies -- Shortage of material canShortage of material can
disrupt the operation and excess storage can increase carrying costdisrupt the operation and excess storage can increase carrying cost
SUCCESS IN HIGH VOLUME SYSTEMSSUCCESS IN HIGH VOLUME SYSTEMS

5. SCHEDULING IN LOW VOLUME SYSTEMSSCHEDULING IN LOW VOLUME SYSTEMS
 Scheduling for low volume systems with many variations inScheduling for low volume systems with many variations in
requirements is calledrequirements is called Job Shop SchedulingJob Shop Scheduling
 The assignment of jobs to processing centers is calledThe assignment of jobs to processing centers is called
LoadingLoading
 Jobs are assigned to work centers without regard to theJobs are assigned to work centers without regard to the
capacity of the work center. It is calledcapacity of the work center. It is called Infinite LoadingInfinite Loading
 Jobs are assigned to work centers taking into account theJobs are assigned to work centers taking into account the
work center capacity and job processing times. It is calledwork center capacity and job processing times. It is called
Finite LoadingFinite Loading
 Determining the order in which jobs at work center will beDetermining the order in which jobs at work center will be
processed is called Sequencingprocessed is called Sequencing

6. SEQUENCINGSEQUENCING
 SequencingSequencing is determining the order in which jobs at ais determining the order in which jobs at a
work center will be processedwork center will be processed
 An area where one or a few workers and / or machinesAn area where one or a few workers and / or machines
perform similar work is calledperform similar work is called WorkstationWorkstation
 Simple heuristics used to select the order in which jobs willSimple heuristics used to select the order in which jobs will
be processed is calledbe processed is called Priority RulesPriority Rules

7.  FCFS - First Come, First ServedFCFS - First Come, First Served
 SPT - Shortest Processing TimeSPT - Shortest Processing Time
 EDD - Earliest Due DateEDD - Earliest Due Date
 CR - Critical RatioCR - Critical Ratio
 S/O - Slack per OperationS/O - Slack per Operation
 Rush - EmergencyRush - Emergency
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PRIORITY RULESPRIORITY RULES
Everything is
# 1 Priority

8. PERFORMANCE MEASURES OF SEQUENCEPERFORMANCE MEASURES OF SEQUENCE
 Job Flow TimeJob Flow Time - This is the length of time a job remains at- This is the length of time a job remains at
a particular work station. It includes processing time, waitinga particular work station. It includes processing time, waiting
time, transportation time between operations and othertime, transportation time between operations and other
unexpected delay. The average flow time for a group of jobsunexpected delay. The average flow time for a group of jobs
is equal to the total flow time (total cumulative) divided byis equal to the total flow time (total cumulative) divided by
the number of jobs.the number of jobs.
 Job LatenessJob Lateness – This is the length of time the job completion– This is the length of time the job completion
date is expected to exceed the date the job was promised todate is expected to exceed the date the job was promised to
a customer. If we only record differences for jobs witha customer. If we only record differences for jobs with
completion times that exceed due dates, and assign zeroscompletion times that exceed due dates, and assign zeros
to jobs that are early, the term we use to refer to that isto jobs that are early, the term we use to refer to that is JobJob
TardinessTardiness..
 MakespanMakespan – Makespan is the total time needed to complete– Makespan is the total time needed to complete
a group of jobs. It is the length of time between the start ofa group of jobs. It is the length of time between the start of
the first job in the group and the completion of the last job inthe first job in the group and the completion of the last job inAverage number of jobs = Total flow time / Makespan

9. WHY SCHEDULING CAN BE DIFFICULTWHY SCHEDULING CAN BE DIFFICULT
 An operation must deal with variability in setup times,An operation must deal with variability in setup times,
processing times, interruptions, and changes in the set ofprocessing times, interruptions, and changes in the set of
jobs.jobs.
 There is no method for identifying the optimal schedule,There is no method for identifying the optimal schedule,
and it would be virtually impossible to sort through the vastand it would be virtually impossible to sort through the vast
number of possible alternatives to obtain the bestnumber of possible alternatives to obtain the best
schedule. It is a on going task for a manager.schedule. It is a on going task for a manager.

10. MINIMIZING SCHEDULING DIFFICULTIESMINIMIZING SCHEDULING DIFFICULTIES
 Setting realistic due datesSetting realistic due dates
 Forecasting on bottleneck operationsForecasting on bottleneck operations
 Considering lot splitting for large jobsConsidering lot splitting for large jobs

11. MATHMATH
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