A Multiagent
Framework for
Integrating RevenueCreating Control
Processes
AGIFORS
Reservation & Yield Management
Study Group Annual Meeting
Berlin 16 – 19 April 2002
Klaus Weber
Lufthansa Systems
Junqing Sun
Civil Aviation Institute of China
Zhaohao Sun
Bond University, Australia
Who is Who?
Zhaohao Sun
– Bond University
Gold Coast, Australia
Junqing Sun
– Civil Aviation Institute of China
Tianjin, China
Klaus Weber
– Lufthansa Systems
Berlin, Germany
18 April 2002
Chart 2
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Special Thanks to
Johannes J. Bisschop
– Paragon Decision Technology
The Netherlands
Agenda
Motivation
Revenue-Creating Control Processes
Intelligent Agents and Multiagent Systems
A Multiagent Framework
Conclusions / Outlook
18 April 2002
Chart 3
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Agenda
Motivation
Revenue-Creating Control Processes
Intelligent Agents and Multiagent Systems
A Multiagent Framework
Conclusions / Outlook
18 April 2002
Chart 4
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Motivation
Key idea
I System performance depends not only on components but also on
– System structure
– Interrelationship among the components
I Integrated optimization of interdependent processes is better than
independent optimization
I Some achievements in vertical integration of business processes
I However, usual situation at airlines:
– distributed hardware
– separated databases
– different organizational units
but
– many generally identical functions, e.g. forecastint, optimization
– use same data
18 April 2002
Chart 5
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Motivation (cont)
Software engineering viewpoint
I Systems integration increases system complexity
I Object-oriented paradigm
– is a powerful tool but not the most appropriate to deal with complexity
I Agent-oriented techniques
– new means of analyzing, designing and building complex software
systems
– Multiagent technology is a new paradigm for distributed decision
making (i.e. problem solving)
Here we present
I Multiagent framework for integration of revenue-creating control processes
 Fleet assignment, Pricing, Revenue management
under one roof
18 April 2002
Chart 6
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Motivation (cont)
Great
Tower Wall
of Babel
Badly-organized
system

disastrous
result
Well-organized
system
sustainable
result
18 April 2002
Chart 7
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Agenda
Motivation
Revenue-Creating Control Processes
Intelligent Agents and Multiagent Systems
A Multiagent Framework
Conclusions / Outlook
18 April 2002
Chart 8
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Revenue-Creating Control Processes
O&D Revenue Management System
Flight Schedule
Data Loading
Unconstraining
PNR Data
Forecast
Kernel
Forecaster
Availabilities
Exponential Smoothing
Induction Trees
Actual Data
Forecast Building
Forecast Interface Database
Overbooking Optimization
O&D Optimizer
Flight Schedule
Booking Class Optimization
Fares Database
O&D Group Optimizer
Group Database
Optimizer
Bid Price Server
Optimizer Database
18 April 2002
Chart 9
Availability Processor
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Revenue-Creating Control Processes
Fleet Assignment
Internal Fare Data
Internal Fare Data
Market Size
Forecaster
ATPCO
MIDT
MIDT
Connection Builder
Market Demand
Profitability
Market
Share Model
Flight Schedule
Evaluation
Spill
& Recapture
Model
Revenue & Cost
Average Revenue
Estimation
Objective Function
Assignment
18 April 2002
Chart 10
ATPCO
Assignment Evaluation
Fleet
Optimizer
Assignment
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Parameter Calibration
Multinomial Logit Model
Unconstraining
Cost Model
Mixed Integer Program
Simulated Annealing
Revenue-Creating Control Processes
Pricing
Internal Fare Data
Price
Elasticity
Alternative
Analyzer
Model
ATPCO
Competitor Reaction
Analyzer
MIDT
Traveller Preference
Analyzer
Market Size
Competitor
Fare Actions
Parameter Calibration
Multinomial Logit Model
Forecaster
Market
Stimulation
Model
Market Change
Revenue Estimation
Auto Matcher
Product Change
18 April 2002
Chart 11
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Cost Estimation
Booking Class Optimization
Cost Model
Revenue-Creating Control Processes
Differences & Commonnesses
I Differences
– Not all databases are commonly used.
– Each system comprises some specific functions
RM
FA
Pricing
18 April 2002
Chart 12
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Revenue-Creating Control Processes
Differences & Commonnesses (cont.)
I Commonnesses
RM
FA
– Some databases are used by all systems.
– Each system comprises functions which are part
Pricing
of the other systems as well.
– Each system is composed of inter-related sub-systems.
 Each System is hierarchical.
– Some sub-systems are hierarchical themselves.
– Relationship between sub-systems varies, e.g. peer, client-server,
team.
– Whether system components can be considered primitive or complex
depends on the viewpoint.
– It is possible to distinguish between interactions among sub-systems
and the interaction between sub-systems.
 Each system is decomposable to some degree.
18 April 2002
Chart 13
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Revenue-Creating Control Processes
Complexity
Canonical Complex System [Jennings & Wooldridge 2000]
Sub-system
Sub-system component
Composed of
Frequent interaction
Infrequent interaction
18 April 2002
Chart 14
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Revenue-Creating Control Processes
Integrated View
I Optimization
– Method 1, Method 2, ..., Method n
I Forecasting
– Method 1, Method 2, ..., Method n
I Parameter Estimation
– Method 1, Method 2, ..., Method n
I Data Pre-Processing
– Method 1, Method 2, ..., Method n
I Other algorithms
– Specific (complex) calculations
– Auxiliary calculations
18 April 2002
Chart 15
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Model specific
Agenda
Motivation
Revenue-Creating Control Processes
Intelligent Agents and Multiagent Systems
A Multiagent Framework
Conclusions / Outlook
18 April 2002
Chart 16
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Intelligent Agents and Multiagent Systems
What is an Agent?
I Agents can perform some activities
I ... we define an agent
autonomously.
as referring to a
At a minimum, they must be able to carry out
component of
some instructions ... without the help of other
software and/or
agents. Additionally, they may be able to
hardware which is
make decisions of various levels of complexity capable of acting
on their own.
exactly in order to
accomplish tasks on
I Agents are part of a community.
behalf of its user.
No agent is an island. When agents co-exist
in a community, although some may exhibit a I ... it is
very high degree of autonomy, they are never
an umbrella term,
truly independent of the other agents because meta-term or class,
they share an environment and therefore may which covers a range of
compete for resources, whether intentionally
other more specific
or not.
agent types ...
[Hayes1999]
18 April 2002
Chart 17
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
[Nwana1996]
Intelligent Agents and Multiagent Systems
What is an Agent?
What is Agent-Oriented Software? [Wooldridge1997]
I ... an agent is an encapsulated computer system that is situated in some
environment, and that is capable of flexible, autonomous action in that
environment in order to meet its design objectives ...
I Agents are
– Clearly identifiable problem solving entities
– Situated in a particularly environment
– Designed to fulfill a specific role
– Autonomous
– Capable of exhibiting flexible problem solving behavior
18 April 2002
Chart 18
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Intelligent Agents and Multiagent Systems
What is a Multiagent System?
What is a multiagent system? [Sun2001]
I A multiagent system is a group of agents that work together to find
answers to problems that are beyond the individual capabilities of
knowledge of each agent.
I A multiagent system (MAS)
– is a loosely coupled network of agents,
– (which can be distributed over several computers)
– that communicate together
– to accomplish individual and/or common goals,
– which cannot be solved by one single agent alone.
– MAS do not have global system control over the agents,
– usually uses decentralized data.
– Communication between agents mainly takes place asynchronously.
18 April 2002
Chart 19
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Intelligent Agents and Multiagent Systems
What is a Multiagent System? (cont)
 Questions
I
I
I
I
Which agent roles?
Which interactions between agents?
Which acquaintances between agents?
Which system structure?
To be cleared later
18 April 2002
Chart 20
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Intelligent Agents and Multiagent Systems
Complex Systems and Agents
Integration of Revenue Management, Fleet Assignment and Pricing results
in a complex system.
 Are multiagent systems the appropriate paradigm?
Paradigm
shift?
Software Engineering Viewpoint
Principle mechanisms to manage complexity
I Decomposition
– divide problem, deal and solve parts in relative isolation
I Abstraction
– define simplified model, emphasize some details,
suppress others
I Organisation
– identify and manage inter-relationships between
problem solving components
18 April 2002
Chart 21
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
limit the
designer’s
scope
Intelligent Agents and Multiagent Systems
Complex Systems and Agents (cont.)
Decomposition
Abstraction
I sub-systems work
together to achieve
functionality of their
parent system
I interactions occur at
unpredictable times, for
unpredictable reasons,
between unpredictable
components
I minimize semantic gap
I broad variety of
between units of
relationships
analysis and the
– peers  control
constructs in the solution
hierarchies
paradigm
– short-term 
ongoing
I system  sub-system
 Decomposition
I relationships may
frequently change
I interplay between subsystems
 organizations are first= high level social
class entities in agent
interaction
systems
 multiple, interacting,
autonomous
components
I agents cooperate to
achieve common
objectives
I localisation and
encapsulation
MAS P
18 April 2002
Chart 22
MAS P
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Organization
MAS P
Intelligent Agents and Multiagent Systems
Multiagent Systems and OO Software Engineering
Important differences
I Objects are generally passive in nature
I Objects encapsulate state and behavior - they do not encapsulate
behavior activation (action choice)
I Object-orientation fails to provide an adequate
set of concepts and mechanisms for
modeling such systems
I Object-oriented approaches provide
minimal support for structuring
collectives.
18 April 2002
Chart 23
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Agenda
Motivation
Revenue-Creating Control Processes
Intelligent Agents and Multiagent Systems
A Multiagent Framework
Conclusions / Outlook
18 April 2002
Chart 24
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
A Multiagent Framework
Agent Roles
I Main parts in software architecture [Perry1992]
– Data elements
Databases
agents
– Processing elements
– Connecting elements
agents
I Agent roles
– Coordinating agents
– Dispatcher agents
– Control agents
– Worker agents
18 April 2002
Chart 25
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Agent interaction (next slide)
Optimization
Forecasting
Data
OtherPre-Processing
algorithms
Parameter
Estimation
PNR
update
e.g. observe
detect
booking
forecast,
change
level,
analysecapacity
system
state,
register deviating
forecast change
booking
significant
system trend
change
perform
extract
itinerary
maximum
information
likelihoodfrom PNR
e.g. calculate
spill and
recapture
unconstraining,
compute
EMSR
curve,
estimation,
train
tree
solveinduction
linear program
compute weights by least squares fit
A Multiagent Framework
Agent Interaction
I Dispatcher agents
– Keep track of idle worker agents
– Divide computational work effectively
I Coordinating agents
– Gather status information from agents below them in the hierarchy
I To be defined
– Interdependencies and interrelations of roles
– Agent interactions: messages
– Message priorities (e.g. highest priority for user interference)
– Who? With whom? How?
– Not: When?
18 April 2002
Chart 26
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
A Multiagent Framework
System Overview
DB 1
Worker
agents
Control
agent
Dispatcher
agent
DB 3
Coordinating
agent
DB 4
DB 2
DB 5
Dispatcher
agent
Coordinating
agent
Control
agent
DB 6
Dispatcher
agent
DB 7
DB 8
Coordinating
agent
Dispatcher
agent
Control
agent
Coordinating
agent
Control
agent
DB 9
18 April 2002
Chart 27
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Control
agent
DB 10
A Multiagent Framework
Tools
I Several development tools for agent-oriented software available
– Commercial tools
– Research prototype
http://www.agentbuilder.com/AgentTools
I Toolbox
– Libraries including functional agent
components
– Predefined coordination and
organisation relations
– General planning and scheduling
mechanisms
– Editors
– Visualisation tools
18 April 2002
Chart 28
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
British
Telecom
Agent
Oriented
Software
Paragon
Decision
Technology
Agenda
Motivation
Revenue-Creating Control Processes
Intelligent Agents and Multiagent Systems
A Multiagent Framework
Conclusions / Outlook
18 April 2002
Chart 29
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Conclusions / Outlook
I Vertical integration requires adequate software engineering techniques
 Multiagent Framework
I Revenue management, pricing, and fleet assignment systems have all
characteristics of complex systems
I From a software engineering viewpoint the new paradigm of multiagent
technology is advantageous for development of complex systems.
I We introduced agents, multiagent systems, agent roles and agent
interaction both generally and with respect to revenue management,
pricing and fleet assignment systems.
I Special development tools already exist.
18 April 2002
Chart 30
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Outlook
I Further characterise agents within the framework
I Develop a prototype using multiagent technology
I Study on integration of existing systems
using multiagent technology
I Study on integration of additional processes
e.g. processes in airline operations control
18 April 2002
Chart 31
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes
Thank You for Your Attention!
Any Questions?
[email protected]
18 April 2002
Chart 32
Klaus Weber, Junqing Sun, Zhaohao Sun:
A Multiagent Framework for Integrating Revenue-Creating
Control Processes