MD254: e-Service Operations Management

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MD254 e-Service Operations Management

• Managing Waiting Lines in Traditional Services
  and e-Services

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Overview

• Background
• Queues and Queueing Systems
• Psychology of Waiting
• Queues in a Traditional Service
• Queues in an e-Service
• Features of Queueing Systems
• Summary

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Background
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Background

• Waiting lines are a part of any service
• Physical services have physical waiting lines
• Call centers have queues of phone calls
• e-Services have waiting times between when you
  click a URL in your browser and when the
  e-Service returns a web page
• During that time period, you are waiting in a
  virtual waiting line of peoples requests

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Background

• Competitive importance of fast or at least,
  reasonable delivery speed
• Physical service
• People can see the waiting line, and this affects
  their behavior and perceptions
• Call center service operations
• People end up on hold, which can affect their
  behavior and perceptions
• e-Service
• 8-second rule of thumb for delivering web pages
  has gotten steadily faster over time

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Queues and Queueing Systems
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Queues and Queueing Systems

• Queue
• A line of waiting customers who require service
  from a service system made up of one or more
  servers

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Queues and Queueing Systems

• Location of Queues Relative to Customer
• Customer goes to Server
• Retailing queue builds up in front of cash
  register
• Restaurants queue builds up at front door
  customers food order queues in kitchen
• Server goes to Customer
• Plumber queue is on a list of destinations to
  visit

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Queues and Queueing Systems

• Networks of Queues
• Queueing Systems are often made up of networks of
  waiting lines
• Disney World
• longer queues are partitioned into subqueues
• different entertainment provided during each
  subqueue
• Telecommunications Services
• Phone calls travel across a queueing network of
  phone system devices
• e-Service
• Web servers, application servers, database
  servers, and so on, make up a network of queues
  that manage and process a waiting line of
  customers

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Psychology of Waiting
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Psychology of Waiting

• Physical Services
• People dislike empty time, so it is often good to
  fill up such time in useful ways
• Service related diversions (i.e., filling out
  forms) can be accomplished during waiting, to
  shorten the eventual service time, and make
  better use of service provider times (e.g.,
  doctors)
• Customers worry about their place in line, and
  whether theyve been forgotten, so it is often
  good to remind them you have not forgotten
• Customers have certain expectations about how a
  waiting line will be run, and when this
  expectation is violated (e.g., a later arrival
  being served first), they may get mad
• Experiences during waiting times are also part of
  the service experience, leading to good or bad
  word of mouth, and retaining or losing the
  customer

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Psychology of Waiting

• e-Services
• Customers cannot usually see the queue of
  customers in front of their service request
  they can only sit there and hope that the next
  web page comes up
• Difficult to see why service may be slow
• Often difficult to find non-electronic service
  personnel, to assist one with the e-service
• Offline activities (services delivered to home,
  delivery of products purchased online) provide
  major portions of perceived service queues
• Often good to keep customer informed about these

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Queues in a Traditional Service
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Queues in a Traditional Service

• Single Queue, Single Server
• Single Queue, Multiple Server
• Multiple Queue, Multiple Server
• Job Shop
• Multiple queue, Multiple server
• Jobs can flow from any server to any other server
• Batch Flow
• Jobs flow from server to server in groups
• Discrete Flow (Assembly) Line
• Each job individually visits a number of servers
  in a specific order

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Queues in a Traditional ServiceAn Emergency Room
Gunshot Wound
Priority Queue
Pool of Servers
Broken Arm
Non-Priority Queue
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Queues in an e-Service
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Queues in an e-ServiceCommon e-Service Processes
URL Click
HTML Page Web Server
Client Computer
Stage 1
HTML Page
URL Click
CGI Call
Web Server
Client Computer
Common Gateway Interface Program
Stage 2
HTML Page
Results in HTML
URL Click
Calls
Client Computer
Calls
Stage 3
Web Server
Application Server
Database Server
Results in HTML
HTML Page
Database Table
Stage 4
Stage 3 structure may request information
from all sorts of information resources outside
of organization
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Queues in an e-Service
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Queues in an e-ServiceA Network of Queues
Queue
Queue
Queue
Queue
Database Server
Load Balancer
Queue
Queue
Web Servers
Application Servers
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Features of Queueing Systems
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Features of Queueing Systems

• Calling population
• Arrival process
• Queue configuration
• Queue discipline
• Service process

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Features of Queueing Systems

• Calling population
• Composition
• Homogeneous customers
• Heterogeneous customers (multiple classes of
  customers)
• How many groups?
• Characteristics of groups?
• Size
• Finite how many?
• Infinite

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Features of Queueing Systems

• Arrival process
• The demand for a service has temporal and spatial
  components that determine how demand arrives at
  the service system
• Nature
• Discrete/Fixed
• Scheduled
• Stochastic/Random
• Inter-arrival times (period between arrivals) are
  commonly assumed to be distributed exponentially
• Customer Behaviors
• Balking seeing length of waiting line, and
  leaving before entering line
• Reneging leaving the waiting line after being
  in it for a while

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Features of Queueing Systems

• Queue configuration
• The number of queues, their locations, their
  spatial requirements, and their effects on
  customer behavior
• Single queue vs. multiple queues
• Queue traffic controller? (bouncer, lady in bank
  at lunchtime yelling out which line is empty)
• Jockeying behavior customers leave one line for
  another shorter one

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Features of Queueing Systems

• Queue discipline
• A policy established by management to select the
  next customer from the queue for service
• First-Come, First-Served (FCFS)
• Person who arrived first goes next
• Shortest Processing Time
• Job that will take the shortest time to process
  goes next
• Priority Based Queueing Disciplines
• Bouncer at bar lets in the beautiful people
  first rest of us have to wait (or tip heavily
  to get past bouncer) until space is available
  late at night
• Emergency room helps people with really bad
  injuries first
• Many, many, many potential policies have been
  developed for different systems

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Features of Queueing Systems

• Service process
• The tasks that must be accomplished to complete
  the process
• The number of servers
• The location of servers where the tasks are
  completed
• The length of time for completing each task

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Summary
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Summary

• All production systems have waiting lines even
  the ones that are scheduled to try to eliminate
  waiting
• Queueing systems are important in all services
  traditional and e-service
• Managers must understand how to model the
  traditional and e-services
• Several important features of queueing systems
  define how queues function