Title: MD254: e-Service Operations Management
1MD254 e-Service Operations Management
- Managing Waiting Lines in Traditional Services
and e-Services
2Overview
- Background
- Queues and Queueing Systems
- Psychology of Waiting
- Queues in a Traditional Service
- Queues in an e-Service
- Features of Queueing Systems
- Summary
3Background
4Background
- 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
5Background
- 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
6Queues and Queueing Systems
7Queues and Queueing Systems
- Queue
- A line of waiting customers who require service
from a service system made up of one or more
servers
8Queues 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
9Queues 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
10Psychology of Waiting
11Psychology 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
12Psychology 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
13Queues in a Traditional Service
14Queues 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
15Queues in a Traditional ServiceAn Emergency Room
Gunshot Wound
Priority Queue
Pool of Servers
Broken Arm
Non-Priority Queue
16Queues in an e-Service
17Queues 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
18Queues in an e-Service
19Queues in an e-ServiceA Network of Queues
Queue
Queue
Queue
Queue
Database Server
Load Balancer
Queue
Queue
Web Servers
Application Servers
20Features of Queueing Systems
21Features of Queueing Systems
- Calling population
- Arrival process
- Queue configuration
- Queue discipline
- Service process
22Features 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
23Features 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
24Features 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
25Features 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
26Features 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
27Summary
28Summary
- 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