1. 2 Chapter 9 Service Operations Planning and Scheduling

1 1 2002 South-Western/Thomson Learning 2002 South-Western/Thomson Learning TMTM

Slides preparedSlides preparedby John Loucksby John Loucks

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Chapter 9Chapter 9Chapter 9Chapter 9

Service OperationsService Operations

Planning and SchedulingPlanning and Scheduling

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OverviewOverviewOverviewOverview

IntroductionIntroduction Scheduling Quasi-Manufacturing Service OperationsScheduling Quasi-Manufacturing Service Operations Scheduling Customer-as-Participant Service Scheduling Customer-as-Participant Service

OperationsOperations Scheduling Customer-as-Product Service OperationsScheduling Customer-as-Product Service Operations Wrap-Up: What World-Class Companies DoWrap-Up: What World-Class Companies Do

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IntroductionIntroductionIntroductionIntroduction

ServicesServices are operations with: are operations with: Intangible outputs that ordinarily cannot be Intangible outputs that ordinarily cannot be

inventoriedinventoried Close customer contactClose customer contact Short lead timesShort lead times High labor costs relative to capital costsHigh labor costs relative to capital costs Subjectively determined qualitySubjectively determined quality

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Facts about service businesses:Facts about service businesses: Enormous diversityEnormous diversity Service businesses can be any sizeService businesses can be any size Twice as many non-retail service businesses as Twice as many non-retail service businesses as

retailretail Technical training important due to significant Technical training important due to significant

dependence on computers, automation and dependence on computers, automation and technologytechnology

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Other Facts about service businesses:Other Facts about service businesses: Service workers well paid relative to Service workers well paid relative to

manufacturingmanufacturing Need better planning, controlling, and Need better planning, controlling, and

management to stay competitivemanagement to stay competitive

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Some of the Largest Service BusinessesSome of the Largest Service BusinessesSome of the Largest Service BusinessesSome of the Largest Service Businesses

Rank in the top 20 US Corporations:Rank in the top 20 US Corporations: AT&TAT&T Wal-MartWal-Mart CitigroupCitigroup State FarmState Farm SBC CommunicationsSBC Communications Sear, Roebuck & CompanySear, Roebuck & Company

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Spectrum of Service IndustriesSpectrum of Service IndustriesSpectrum of Service IndustriesSpectrum of Service Industries

TransportationTransportation BankingBanking RetailingRetailing Health CareHealth Care EntertainmentEntertainment

InsuranceInsurance Real EstateReal Estate CommunicationsCommunications UtilitiesUtilities … … and moreand more

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No Clear Line BetweenNo Clear Line BetweenManufacturing and Service FirmsManufacturing and Service Firms

No Clear Line BetweenNo Clear Line BetweenManufacturing and Service FirmsManufacturing and Service Firms

EveryEvery business, whether manufacturing or service, business, whether manufacturing or service, has a mix of customer service aspects and production has a mix of customer service aspects and production aspects in its operationsaspects in its operations

Manufacturing has much to learn from services that Manufacturing has much to learn from services that excelexcel

Services have much to learn from manufacturers that Services have much to learn from manufacturers that excelexcel

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Manufacturing and Service JobsManufacturing and Service JobsManufacturing and Service JobsManufacturing and Service Jobs

Percentage of US JobsPercentage of US Jobs

19881988 1998 1998 2008* 2008*

Manufacturing JobsManufacturing Jobs 16.1% 16.1% 13.4% 13.4% 11.6% 11.6%

Service JobsService Jobs 66.2 66.2 70.870.8 73.973.9

* Projected* Projected

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Operations StrategiesOperations StrategiesOperations StrategiesOperations Strategies

Positioning strategiesPositioning strategies contain two elements: contain two elements: Type of service designType of service design

Standard or customStandard or custom Amount of customer contactAmount of customer contact Mix of physical goods and intangible servicesMix of physical goods and intangible services

Type of production processType of production process Quasi-manufacturingQuasi-manufacturing Customer-as-participantCustomer-as-participant Customer-as-productCustomer-as-product

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Types of Service OperationsTypes of Service OperationsTypes of Service OperationsTypes of Service Operations

Quasi-manufacturingQuasi-manufacturing Production occurs much as manufacturingProduction occurs much as manufacturing Physical goods dominant over intangible servicesPhysical goods dominant over intangible services

Customer-as-participantCustomer-as-participant High degree of customer involvementHigh degree of customer involvement Physical goods may or may not be significantPhysical goods may or may not be significant Service either standard or customService either standard or custom

Customer-as-productCustomer-as-product Service performed on customer... usually customService performed on customer... usually custom

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Scheduling Challenges in ServicesScheduling Challenges in ServicesScheduling Challenges in ServicesScheduling Challenges in Services

Planning and controlling day-to-day activities Planning and controlling day-to-day activities difficult due to:difficult due to: Services produced and delivered by peopleServices produced and delivered by people Pattern of demand for services is non-uniformPattern of demand for services is non-uniform

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Non-Uniform DemandNon-Uniform DemandNon-Uniform DemandNon-Uniform Demand

Cannot inventory services in advance of high-demand Cannot inventory services in advance of high-demand periods, so businesses use following tactics:periods, so businesses use following tactics: Preemptive actions to make demand more uniformPreemptive actions to make demand more uniform

Off-peak incentives/discounts (telephone)Off-peak incentives/discounts (telephone) Appointment schedules (dentist)Appointment schedules (dentist) Fixed schedules (airline)Fixed schedules (airline)

Make operations more flexible so it is easier to Make operations more flexible so it is easier to vary capacityvary capacity

Part-time personnel (supermarket)Part-time personnel (supermarket) Subcontractors (postal service)Subcontractors (postal service) In-house standby resources (fire department)In-house standby resources (fire department)

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Non-Uniform DemandNon-Uniform DemandNon-Uniform DemandNon-Uniform Demand

Additional tactics used by businesses:Additional tactics used by businesses: Anticipate demand and schedule employees during Anticipate demand and schedule employees during

each time period to meet demandeach time period to meet demand Allow waiting lines to formAllow waiting lines to form

These two tactics will be covered in greater detailThese two tactics will be covered in greater detail

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Scheduling Quasi-Manufacturing ServicesScheduling Quasi-Manufacturing ServicesScheduling Quasi-Manufacturing ServicesScheduling Quasi-Manufacturing Services

Product-Focused OperationsProduct-Focused Operations Resemble product-focused production linesResemble product-focused production lines Customer demand is forecast and capacity Customer demand is forecast and capacity

decisions made just as in manufacturingdecisions made just as in manufacturing High volumes of standardized productsHigh volumes of standardized products Management focused on controlling production Management focused on controlling production

costs, product quality, and delivery of physical costs, product quality, and delivery of physical goodsgoods

Example... McDonald’s back-room operationExample... McDonald’s back-room operation

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Scheduling Quasi-Manufacturing ServicesScheduling Quasi-Manufacturing ServicesScheduling Quasi-Manufacturing ServicesScheduling Quasi-Manufacturing Services

Process-Focused OperationsProcess-Focused Operations Managed like job shops in manufacturingManaged like job shops in manufacturing Input-output control important to balance capacity Input-output control important to balance capacity

between operationsbetween operations Gantt charts used to coordinate flows between Gantt charts used to coordinate flows between

departmentsdepartments Sequence of jobs consider sequencing rules, Sequence of jobs consider sequencing rules,

changeover costs, and flow timeschangeover costs, and flow times

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Work Shift SchedulingWork Shift SchedulingWork Shift SchedulingWork Shift Scheduling

Three difficulties in scheduling services:Three difficulties in scheduling services: Demand variabilityDemand variability Service time variabilityService time variability Availability of personnel when neededAvailability of personnel when needed

Managers use two tactics:Managers use two tactics: Use full-time employees exclusivelyUse full-time employees exclusively Use some full-time employees as base and fill in Use some full-time employees as base and fill in

peak demand with part-time employeespeak demand with part-time employees

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Example: Scheduling EmployeesExample: Scheduling EmployeesExample: Scheduling EmployeesExample: Scheduling Employees

The owner of a haircutting shop wants to The owner of a haircutting shop wants to convert from a drop-in system of customer arrivals to convert from a drop-in system of customer arrivals to an appointment system.an appointment system.

Each customer requires an average of 30 Each customer requires an average of 30 minutes of a stylist’s time. The stylists are all full-minutes of a stylist’s time. The stylists are all full-time employees and can work any 4 consecutive days time employees and can work any 4 consecutive days per week from 10 a.m. to 7 p.m. (with an hour off for per week from 10 a.m. to 7 p.m. (with an hour off for lunch), Monday through Saturday.lunch), Monday through Saturday.

On the next slide are: 1) average number of On the next slide are: 1) average number of drop-in customers each day, and 2) estimated number drop-in customers each day, and 2) estimated number of customer appointments each day.of customer appointments each day.

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Mon.Mon. Tue.Tue. Wed.Wed. Thu.Thu. Fri.Fri. Sat.Sat. TotalTotal

Drop-insDrop-ins 4040 3030 1010 2020 3030 6060 190190

AppointmentsAppointments 3232 3232 3232 3232 3232 3232 192192

a) How many stylists are required to service 32 a) How many stylists are required to service 32 appointments in a day?appointments in a day?

b) What is the minimum number of stylists required per b) What is the minimum number of stylists required per week?week?

c) Use the work shift heuristic procedure to develop the c) Use the work shift heuristic procedure to develop the stylists’ weekly work shift schedules.stylists’ weekly work shift schedules.

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Number of Stylists Required per DayNumber of Stylists Required per Day

Number of customers per dayNumber of customers per day

Number of work hours Number of customersNumber of work hours Number of customers per day per stylistper day per stylist served per hour per served per hour per styliststylist

= 32/((8)(2)) = 2 stylists= 32/((8)(2)) = 2 stylists

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Minimum Number of Stylists Required per Week?Minimum Number of Stylists Required per Week?

Number of Customers per WeekNumber of Customers per Week

Number of Customers per Stylist per WeekNumber of Customers per Stylist per Week

= 192/((8 hr/day)(4 days/week)(2 cust./hr/stylist))= 192/((8 hr/day)(4 days/week)(2 cust./hr/stylist))

= 192/64 = 3 stylists= 192/64 = 3 stylists

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Stylists’ Weekly Work Shift SchedulesStylists’ Weekly Work Shift Schedules

StylistStylist Mon.Mon. Tue.Tue. Wed.Wed. Thu.Thu. Fri.Fri. Sat.Sat.

11 22 22 22 22 22 22

22 22 22 11 11 11 11

33 11 11 11 11 00 00

Note: Pair of days boxed represent days off.Note: Pair of days boxed represent days off.

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Scheduling Customer-as-Participant ServicesScheduling Customer-as-Participant ServicesScheduling Customer-as-Participant ServicesScheduling Customer-as-Participant Services

Must provide customer ease of use/access features.... Must provide customer ease of use/access features.... lighting, walkways, etc.lighting, walkways, etc.

Layouts must focus on merchandising and attractive Layouts must focus on merchandising and attractive display of productsdisplay of products

Employee performance crucial to customer Employee performance crucial to customer satisfactionsatisfaction

Waiting lines used extensively to level demandWaiting lines used extensively to level demand

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Waiting Lines in Service OperationsWaiting Lines in Service OperationsWaiting Lines in Service OperationsWaiting Lines in Service Operations

Waiting lines form because:Waiting lines form because: Demand patterns are irregular or random.Demand patterns are irregular or random. Service times vary among “customers”. Service times vary among “customers”. Managers try to strike a balance between Managers try to strike a balance between

efficiently utilizing resources and keeping efficiently utilizing resources and keeping customer satisfaction high.customer satisfaction high.

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Waiting Line ExamplesWaiting Line ExamplesWaiting Line ExamplesWaiting Line Examples

Computer printing jobs waiting for printingComputer printing jobs waiting for printing Workers waiting to punch a time clockWorkers waiting to punch a time clock Customers in line at a drive-up windowCustomers in line at a drive-up window Drivers waiting to pay a highway tollDrivers waiting to pay a highway toll Skiers waiting for a chair liftSkiers waiting for a chair lift Airplanes waiting to take offAirplanes waiting to take off

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Waiting Line AnalysisWaiting Line AnalysisWaiting Line AnalysisWaiting Line Analysis

Assists managers in determining:Assists managers in determining: How many servers to useHow many servers to use Likelihood a customer will have to waitLikelihood a customer will have to wait Average time a customer will waitAverage time a customer will wait Average number of customers waitingAverage number of customers waiting Waiting line space neededWaiting line space needed Percentage of time all servers are idlePercentage of time all servers are idle

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Waiting Line TerminologyWaiting Line TerminologyWaiting Line TerminologyWaiting Line Terminology

QueueQueue - a waiting line - a waiting line ChannelsChannels - number of waiting lines in a queuing - number of waiting lines in a queuing

systemsystem Service phasesService phases – number of steps in service process – number of steps in service process Arrival rateArrival rate ( () - rate at which persons or things ) - rate at which persons or things

arrive (in arrivals per unit of time)arrive (in arrivals per unit of time) Service rateService rate ( () - rate that arrivals are serviced (in ) - rate that arrivals are serviced (in

arrivals per unit of time)arrivals per unit of time)

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Waiting Line TerminologyWaiting Line TerminologyWaiting Line TerminologyWaiting Line Terminology

Queue disciplineQueue discipline - rule that determines the order in - rule that determines the order in which arrivals are servicedwhich arrivals are serviced

Queue lengthQueue length – number of arrivals waiting for service – number of arrivals waiting for service Time in systemTime in system – an arrival’s waiting time – an arrival’s waiting time andand

service timeservice time UtilizationUtilization – degree to which any part of the service – degree to which any part of the service

system is occupied by an arrivalsystem is occupied by an arrival

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Queuing System StructuresQueuing System StructuresQueuing System StructuresQueuing System Structures

Single Phase - Single ChannelSingle Phase - Single Channel

Single Phase - MultichannelSingle Phase - Multichannel

SS11SS11

SS11SS11

SS22SS22

SS33SS33

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Queuing System StructuresQueuing System StructuresQueuing System StructuresQueuing System Structures

Multiphase - Single ChannelMultiphase - Single Channel

Multiphase - MultichannelMultiphase - Multichannel

SS1212SS1212SS1111SS1111

SS1212SS1212SS1111SS1111

SS2222SS2222SS2121SS2121

SS3232SS3232SS3131SS3131

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Definitions of Queuing System VariablesDefinitions of Queuing System VariablesDefinitions of Queuing System VariablesDefinitions of Queuing System Variables

= average arrival rate= average arrival rate

1/1/ = average time between arrivals = average time between arrivals

µ µ = average service rate for each server = average service rate for each server

1/1/µ µ = average service time = average service time

nn11 = average number of arrivals waiting = average number of arrivals waiting

nnSS = average number of arrivals in the system = average number of arrivals in the system

tt11 = average time arrivals wait = average time arrivals wait

ttSS = average time arrivals are in the system = average time arrivals are in the system

PPnn = probability of exactly = probability of exactly nn arrivals in the system arrivals in the system

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Model 1Model 1 Single channelSingle channel Single phaseSingle phase Poisson arrival-rate distributionPoisson arrival-rate distribution Poisson service-rate distributionPoisson service-rate distribution Unlimited maximum queue lengthUnlimited maximum queue length Examples:Examples:

Single-booth theatre ticket salesSingle-booth theatre ticket sales Single-scanner airport security stationSingle-scanner airport security station

Queuing ModelsQueuing ModelsQueuing ModelsQueuing Models

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Example: Queuing Model 1Example: Queuing Model 1Example: Queuing Model 1Example: Queuing Model 1

Jim Beam pulls stock from his warehouse Jim Beam pulls stock from his warehouse shelves to fill customer orders. Customer orders shelves to fill customer orders. Customer orders arrive at a mean rate of 20 per hour. The arrival rate arrive at a mean rate of 20 per hour. The arrival rate is Poisson distributed. Each order received by Jim is Poisson distributed. Each order received by Jim requires an average of two minutes to pull. The requires an average of two minutes to pull. The service rate is Poisson distributed also.service rate is Poisson distributed also.

Questions to follow ……Questions to follow ……

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Service Rate DistributionService Rate Distribution

QuestionQuestion

What is Jim’s mean service rate per hour?What is Jim’s mean service rate per hour?

AnswerAnswer

Since Jim can process an order in an average Since Jim can process an order in an average time time of 2 minutes (= 2/60 hr.), then the mean service of 2 minutes (= 2/60 hr.), then the mean service

rate, µ, equals 1/(mean service time), or 60/2 =rate, µ, equals 1/(mean service time), or 60/2 =

30/hr.30/hr.

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Average Time in the SystemAverage Time in the System

QuestionQuestionWhat is the average time an order must wait What is the average time an order must wait

from from the time Jim receives the order until it is the time Jim receives the order until it is finished finished being processed (i.e. its turnaround being processed (i.e. its turnaround time)?time)?

AnswerAnswerWith With = 20 per hour and = 20 per hour and = 30 per hour, the = 30 per hour, the average time an order waits in the system is:average time an order waits in the system is: t tSS = 1/(µ - = 1/(µ - ) = 1/(30 - 20) ) = 1/(30 - 20)

= 1/10 hour or 6 minutes= 1/10 hour or 6 minutes

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Average Length of QueueAverage Length of Queue

QuestionQuestionWhat is the average number of orders Jim has What is the average number of orders Jim has waiting to be processed?waiting to be processed?

AnswerAnswerThe average number of orders waiting in the The average number of orders waiting in the queue is: nqueue is: n11 = = 22/[µ(µ - /[µ(µ - )] )]

= (20)= (20)22/[(30)(30-20)]/[(30)(30-20)] = 400/300 = 400/300 = 4/3 or 1.33 orders= 4/3 or 1.33 orders

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Utilization FactorUtilization Factor

QuestionQuestionWhat percentage of the time is Jim processing What percentage of the time is Jim processing orders?orders?

AnswerAnswerThe percentage of time Jim is processing The percentage of time Jim is processing

orders is orders is equivalent to the utilization factor, equivalent to the utilization factor, //. . Thus, the Thus, the percentage of time he is processing percentage of time he is processing orders is:orders is:

// = 20/30 = 20/30 = 2/3 or 66.67%= 2/3 or 66.67%

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Model 2Model 2 Single channelSingle channel Single phaseSingle phase Poisson arrival-rate distributionPoisson arrival-rate distribution Constant service rateConstant service rate Unlimited maximum queue lengthUnlimited maximum queue length Examples:Examples:

Single-booth automatic car washSingle-booth automatic car wash Coffee vending machineCoffee vending machine

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The mechanical pony ride machine at the The mechanical pony ride machine at the entrance to a very popular J-Mart store provides 2 entrance to a very popular J-Mart store provides 2 minutes of riding for $.50. Children (accompanied of minutes of riding for $.50. Children (accompanied of course!) wanting to ride the pony arrive according to course!) wanting to ride the pony arrive according to a Poisson distribution with a mean rate of 15 per a Poisson distribution with a mean rate of 15 per hour.hour.

a) What fraction of the time is the pony idle?a) What fraction of the time is the pony idle?b) What is the average number of children waiting to b) What is the average number of children waiting to

ride the pony?ride the pony?c) What is the average time a child waits for a ride?c) What is the average time a child waits for a ride?

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Fraction of Time Pony is IdleFraction of Time Pony is Idle

= 15 per hour= 15 per hour

= 60/2 = 30 per hour= 60/2 = 30 per hour

Utilization = Utilization = // = 15/30 = .5 = 15/30 = .5

Idle fraction = 1 – Utilization = 1 - .5 = .5Idle fraction = 1 – Utilization = 1 - .5 = .5

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Average Number of children Waiting for a RideAverage Number of children Waiting for a Ride

Average Time a Child Waits for a RideAverage Time a Child Waits for a Ride

or 1 minuteor 1 minute

2 2

1

λ (15)n = = .25 children

2μ(μ-λ) 2(30)(30 - 15)

2 2

1

λ (15)n = = .25 children

2μ(μ-λ) 2(30)(30 - 15)

1

λ 15t = = .01667 hours

2μ(μ-λ) 2(30)(30 - 15)1

λ 15t = = .01667 hours

2μ(μ-λ) 2(30)(30 - 15)

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Model 3Model 3 Single channelSingle channel Single phaseSingle phase Poisson arrival-rate distributionPoisson arrival-rate distribution Poisson service-rate distributionPoisson service-rate distribution Limited maximum queue lengthLimited maximum queue length Examples:Examples:

Auto repair shop with limited parking space Auto repair shop with limited parking space Bank drive-thru with limited waiting laneBank drive-thru with limited waiting lane

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Model 4Model 4 Multiple channelMultiple channel Single phaseSingle phase Poisson arrival-rate distributionPoisson arrival-rate distribution Poisson service-rate distributionPoisson service-rate distribution Unlimited maximum queue lengthUnlimited maximum queue length Examples:Examples:

Expressway exit with multiple toll booths Expressway exit with multiple toll booths Bank with multiple teller stationsBank with multiple teller stations

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Scheduling Customer-as-Product ServicesScheduling Customer-as-Product ServicesScheduling Customer-as-Product ServicesScheduling Customer-as-Product Services

Wide range of complexityWide range of complexity Every facet designed around the customerEvery facet designed around the customer Highly trained, motivated, and effective workforce Highly trained, motivated, and effective workforce

critical to successcritical to success Waiting-line analysis can be helpful in determining Waiting-line analysis can be helpful in determining

staffing levelsstaffing levels In more complex operations, simulation is a helpful In more complex operations, simulation is a helpful

tool in scheduling resourcestool in scheduling resources

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Reasons for Simulating OperationsReasons for Simulating OperationsReasons for Simulating OperationsReasons for Simulating Operations

Experimentation with the real system is impossible, Experimentation with the real system is impossible, impractical, or uneconomical.impractical, or uneconomical.

System is so complex that mathematical formulas System is so complex that mathematical formulas cannot be developed.cannot be developed.

Values of the system’s variables are not known with Values of the system’s variables are not known with certainty.certainty.

Problem under consideration involves the passage of Problem under consideration involves the passage of time and simulation could be fastertime and simulation could be faster

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Procedures of Computer SimulationProcedures of Computer SimulationProcedures of Computer SimulationProcedures of Computer Simulation

Define the problem.Define the problem. Develop and computer-program a model of problem.Develop and computer-program a model of problem.

Identify the variables and parameters.Identify the variables and parameters. Specify the decision rules.Specify the decision rules. Gather data and specify variables and parameters.Gather data and specify variables and parameters. Specify time-incrementing procedures.Specify time-incrementing procedures. Specify summarizing procedures.Specify summarizing procedures.

Process the simulation.Process the simulation. Evaluate the results of the simulation.Evaluate the results of the simulation. Recommend a course of action.Recommend a course of action.

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Simulation ExampleSimulation ExampleSimulation ExampleSimulation Example

Whenever an international plane arrives at Whenever an international plane arrives at Lincoln airport the two customs inspectors on duty Lincoln airport the two customs inspectors on duty set up operations to process the passengers.set up operations to process the passengers.

Incoming passengers must first have their Incoming passengers must first have their passports and visas checked. This is handled by one passports and visas checked. This is handled by one inspector. The time required to check a passenger's inspector. The time required to check a passenger's passports and visas can be described by the passports and visas can be described by the probability distribution on the next slide.probability distribution on the next slide.

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Time Required toTime Required to

Check a Passenger'sCheck a Passenger's

Passport and VisaPassport and Visa ProbabilityProbability 20 seconds 20 seconds .20 .20 40 seconds 40 seconds .40 .40 60 seconds 60 seconds .30 .30 80 seconds 80 seconds .10 .10

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After having their passports and visas checked, After having their passports and visas checked, the passengers next proceed to the second customs the passengers next proceed to the second customs official who does baggage inspections. Passengers official who does baggage inspections. Passengers form a single waiting line with the official inspecting form a single waiting line with the official inspecting baggage on a first come, first served basis.baggage on a first come, first served basis.

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The time required for baggage inspection has The time required for baggage inspection has the following probability distribution:the following probability distribution:

Time Required ForTime Required For Baggage InspectionBaggage Inspection ProbabilityProbability

No Time .25No Time .25 1 minute .601 minute .60 2 minutes .102 minutes .10 3 minutes .053 minutes .05

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Random Number MappingRandom Number Mapping

Time Required toTime Required to Check a Passenger's RandomCheck a Passenger's Random Passport and VisaPassport and Visa ProbabilityProbability NumbersNumbers

20 seconds .20 00 - 1920 seconds .20 00 - 19

40 seconds .40 20 - 5940 seconds .40 20 - 59

60 seconds .30 60 - 8960 seconds .30 60 - 89

80 seconds .10 80 seconds .10 90 - 99 90 - 99

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Random Number MappingRandom Number Mapping

Time Required For RandomTime Required For Random Baggage InspectionBaggage Inspection ProbabilityProbability NumbersNumbers

No Time .25 00 - 24No Time .25 00 - 24

1 minute .60 25 - 841 minute .60 25 - 84

2 minutes .10 85 - 942 minutes .10 85 - 94

3 minutes .05 95 - 993 minutes .05 95 - 99

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Next-Event Simulation RecordsNext-Event Simulation Records

For each passenger the following information must be For each passenger the following information must be recorded:recorded: When his service begins at the passport control When his service begins at the passport control

inspectioninspection The length of time for this serviceThe length of time for this service When his service begins at the baggage inspectionWhen his service begins at the baggage inspection The length of time for this serviceThe length of time for this service

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Time RelationshipsTime Relationships

Time a passenger begins serviceTime a passenger begins service

by the passport inspector by the passport inspector

= (Time the previous passenger= (Time the previous passenger

started passport service) started passport service)

+ (Time of previous passenger's+ (Time of previous passenger's

passport service)passport service)

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Time a passenger begins serviceTime a passenger begins service

by the baggage inspector by the baggage inspector

(If passenger does not wait for baggage inspection)(If passenger does not wait for baggage inspection)

= (Time passenger completes service= (Time passenger completes service

with the passport control inspector) with the passport control inspector)

(If the passenger does wait for baggage inspection)(If the passenger does wait for baggage inspection)

= (Time previous passenger completes= (Time previous passenger completes

service with the baggage inspector)service with the baggage inspector)

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Time a customer completes serviceTime a customer completes service

at the baggage inspectorat the baggage inspector

= (Time customer begins service with= (Time customer begins service with

baggage inspector) baggage inspector)

+ (Time required for baggage inspection)+ (Time required for baggage inspection)

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A chartered plane from abroad lands at Lincoln A chartered plane from abroad lands at Lincoln Airport with 80 passengers. Simulate the processing Airport with 80 passengers. Simulate the processing of the first 10 passengers through customs. of the first 10 passengers through customs.

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Simulation Worksheet (partial)Simulation Worksheet (partial)

Passport ControlPassport Control Baggage InspectionsBaggage InspectionsPass. Time Ran. Serv. Time Time Ran. Serv. TimePass. Time Ran. Serv. Time Time Ran. Serv. TimeNum. Beg. Num. Time End Beg. Num. Time EndNum. Beg. Num. Time End Beg. Num. Time End 1 0:00 93 1:20 1:20 1:20 13 0:00 1:201 0:00 93 1:20 1:20 1:20 13 0:00 1:20

2 1:20 63 1:00 2:20 2:20 08 0:00 2:202 1:20 63 1:00 2:20 2:20 08 0:00 2:20 3 2:20 26 :40 3:00 3:00 60 1:00 4:003 2:20 26 :40 3:00 3:00 60 1:00 4:00 4 3:00 16 :20 3:20 4:00 13 0:00 4:004 3:00 16 :20 3:20 4:00 13 0:00 4:00 5 3:20 21 :40 4:00 4:00 68 1:00 5:005 3:20 21 :40 4:00 4:00 68 1:00 5:00

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Simulation Worksheet (continued)Simulation Worksheet (continued)

Passport ControlPassport Control Baggage InspectionsBaggage InspectionsPass. Time Ran. Serv. Time Time Ran. Serv. TimePass. Time Ran. Serv. Time Time Ran. Serv. TimeNum. Beg. Num. Time End Beg. Num. Time EndNum. Beg. Num. Time End Beg. Num. Time End 6 4:00 26 :40 4:40 5:00 40 1:00 6:006 4:00 26 :40 4:40 5:00 40 1:00 6:00 7 4:40 70 1:00 5:40 6:00 40 1:00 7:007 4:40 70 1:00 5:40 6:00 40 1:00 7:00 8 5:40 55 :40 6:20 7:00 27 1:00 8:008 5:40 55 :40 6:20 7:00 27 1:00 8:00 9 6:20 72 1:00 7:20 8:00 23 0:00 8:009 6:20 72 1:00 7:20 8:00 23 0:00 8:00 10 7:20 89 1:00 8:20 8:20 64 1:00 9:2010 7:20 89 1:00 8:20 8:20 64 1:00 9:20

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ExplanationExplanation

For example, passenger 1 begins being served For example, passenger 1 begins being served by the passport control inspector immediately. His by the passport control inspector immediately. His service time is 1:20 (80 seconds) at which time he service time is 1:20 (80 seconds) at which time he goes immediately to the baggage inspector who goes immediately to the baggage inspector who waves him through without inspection. waves him through without inspection.

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ExplanationExplanation

Passenger 2 begins service with passport Passenger 2 begins service with passport inspector 1:20 minutes (80 seconds) after arriving inspector 1:20 minutes (80 seconds) after arriving there (as this is when passenger 1 is finished) and there (as this is when passenger 1 is finished) and requires 1:00 minute (60 seconds) for passport requires 1:00 minute (60 seconds) for passport inspection. He is waved through baggage inspection inspection. He is waved through baggage inspection as well. as well.

This process continues in this manner.This process continues in this manner.

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QuestionQuestion

How long will it take for the first 10 passengers How long will it take for the first 10 passengers to clear customs?to clear customs?

AnswerAnswer

Passenger 10 clears customs after 9 minutes Passenger 10 clears customs after 9 minutes and and 20 seconds.20 seconds.

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QuestionQuestion

What is the average length of time a customer What is the average length of time a customer waits before having his bags inspected after he clears waits before having his bags inspected after he clears passport control? How is this estimate biased?passport control? How is this estimate biased?

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AnswerAnswer

For each passenger calculate his waiting time:For each passenger calculate his waiting time:

(Baggage Inspection Begins) - (Passport Control (Baggage Inspection Begins) - (Passport Control Ends) Ends) =0+0+0+40+0+20+20+40+40+0 = 120 =0+0+0+40+0+20+20+40+40+0 = 120 seconds. seconds.

120/10 = 12 seconds per passenger. 120/10 = 12 seconds per passenger.

This is a biased estimate because we assume This is a biased estimate because we assume that the simulation began with the system empty. that the simulation began with the system empty. Thus, the results tend to underestimate the average Thus, the results tend to underestimate the average waiting time.waiting time.

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Wrap-Up: World-Class PracticeWrap-Up: World-Class PracticeWrap-Up: World-Class PracticeWrap-Up: World-Class Practice

Successful companies have:Successful companies have: Adapted advanced and well-known planning, Adapted advanced and well-known planning,

analyzing, and controlling approaches first analyzing, and controlling approaches first developed in manufacturingdeveloped in manufacturing

Recognized the unique properties of service Recognized the unique properties of service operations and developed novel management operations and developed novel management approaches for these operationsapproaches for these operations

Classify service operations into three types... quasi Classify service operations into three types... quasi manufacturing, customer-as-participant, or manufacturing, customer-as-participant, or customer-as-product...provides framework for customer-as-product...provides framework for analysis.analysis.

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Wrap-Up: World-Class PracticeWrap-Up: World-Class PracticeWrap-Up: World-Class PracticeWrap-Up: World-Class Practice

Factors that create satisfied customersFactors that create satisfied customers Extrinsic quality of servicesExtrinsic quality of services The facilities...comfort, convenience, and The facilities...comfort, convenience, and

atmosphereatmosphere The chemistry between customer and people in The chemistry between customer and people in

service system...friendliness and courtesyservice system...friendliness and courtesy Skill, competence, and professionalism of the Skill, competence, and professionalism of the

personnelpersonnel The value of the service; cost relative to the The value of the service; cost relative to the

quantity of services receivedquantity of services received

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End of Chapter 9End of Chapter 9End of Chapter 9End of Chapter 9

Documents

1. 2 Chapter 9 Service Operations Planning and Scheduling