PRODUCTIONS/OPERATIONS MANAGEMENT

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CHAPTER
18
Waiting Lines
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Disney World

• Waiting in lines does not add enjoyment
• Waiting in lines does not generate revenue

Waiting lines are non-value added occurrences
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Waiting Lines

• Queuing theory Mathematical approach to the
  analysis of waiting lines.
• Goal of queuing analysis is to minimize the sum
  of two costs
• Customer waiting costs
• Service capacity costs
• Waiting lines are non-value added occurrences

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Implications of Waiting Lines

• Cost to provide waiting space
• Loss of business
• Customers leaving
• Customers refusing to wait
• Loss of goodwill
• Reduction in customer satisfaction
• Congestion may disrupt other business operations

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Queuing Analysis
Figure 18.1
Total cost
Customer waiting cost
Capacity cost


Total cost
Cost
Cost of service capacity
Cost of customers waiting
Optimum
Service capacity
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System Characteristics

• Population Source
• Infinite source customer arrivals are
  unrestricted
• Finite source number of potential customers is
  limited
• Number of observers (channels)
• Arrival and service patterns
• Queue discipline (order of service)

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Elements of Queuing System
Figure 18.2
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Queuing Systems
Figure 18.3
Multiple channel
Multiple phase
Channel A server in a service system
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Poisson Distribution
Figure 18.4
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Waiting line Models

• Patient
• Customers enter the waiting line and remain until
  served
• Reneging
• Waiting customers grow impatient and leave the
  line
• Jockeying
• Customers may switch to another line
• Balking
• Upon arriving, decide the line is too long and
  decide not to enter the line

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Waiting Time vs. Utilization
Figure 18.6
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System Performance
Measured by

1. Average number of customers waiting
2. Average time customers wait
3. System utilization
4. Implied cost
5. Probability that an arrival will have to wait

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Queuing Models Infinite-Source

1. Single channel, exponential service time
2. Single channel, constant service time
3. Multiple channel, exponential service time
4. Multiple priority service, exponential service
   time

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Priority Model
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Finite-Source Formulas
Table 18.6
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Finite-Source Queuing
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Other Approaches

• Reduce perceived waiting time
• Magazines in waiting rooms
• Radio/television
• In-flight movies
• Filling out forms
• Derive benefits from waiting
• Place impulse items near checkout
• Advertise other goods/services

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Queuing
QAP9 Managing Queues by Business Rules
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Waiting Line Management
DWL5 Disney Fast Pass Results/Distributing Queues
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Pilot Queue System
DWL6 Fast Pass at Disneys Animal
KingdomStatistics
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Other Queue Perception Improvers
DWL7 Disney WorldTraditional Queue Improvement
Methods