AOSE - Agent Oriented Software Engineering

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AOSE - Agent Oriented Software Engineering

• Alvaro Magri
• 1999s099_at_educ.disi.unige.it

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AOSE index

• AOSE introduction
• Agent-based approach
• GAIA methodology
• Tropos methodology
• Prometheus methodology
• Comparison among the three methodologies

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AOSE Introduction (1)

• Agent-based computing is a synthesis of both
  Artificial Intelligence (AI) and Computer Science
• 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 1
• Agents are being advocated as a next generation
  model for engineering open, complex, distributed
  systems
• Open components can join or leave the dynamic
  operating environment and the operating
  conditions change in unpredictable ways
• Complex the software has a large number of
  components that interact following complex
  interaction protocols every agent has a partial
  view of the environment and there is no
  centralized control

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AOSE Introduction (2)

• In real-world applications the environment is
  open, complex and dynamic. As a consequence,
• Interaction among components cannot be completely
  foreseen at compile-time
• The system's inherent organizational structure
  must be explicitly represented
• We need the right abstractions, methodologies and
  instruments to correctly engineer applications of
  this kind

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AOSE Agent-Based approach (1)
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AOSE Agent-Based approach (2)

• Why should we use an agent-based approach in
  software development?
• Traditional SE techniques for tackling system
  complexity involve
• DECOMPOSITION Agents like active objects
• ABSTRACTION Booch 2 '' at any given level of
  abstraction, we find meaningful collections of
  entities that collaborate to achieve some higher
  level view ''
• ORGANISATION Organizational constructs are
  first-class entities in agent system

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AOSE Agent-Based approach (3)

• AB approach models real-world systems so
• The patterns and the outcomes of interactions are
  inherently unpredictable
• Predicting the behavior of the overall system
  based on its constituent components is extremely
  difficult

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AOSE Agent-Based approach (4)

• To avoid building a methodology from scratch, the
  researchers have extended existing methodologies
  in two areas
• 1) OO methodologies
• 2) KE knowledge engineering
• In OO extensions agents are not simply objects
  the interaction between roles follows complex
  protocols and agents are characterized by their
  mental state
• Existing OO extensions are AO Analysis and
  Design 3, Agent Modelling Technique for Systems
  of BDI agents 4, MASB 5 6, the AO
  Methodology for Enterprise modeling 7, Gaia,
  Tropos, Prometheus, AUML
• In KE extensions, techniques for modeling the
  agent knowledge are provided. These methodologies
  are not as extendibles as the OO ones
• Existing KE extensions are CoMoMAS 8,
  MAS-CommonKADS 9 and Cassiopeia 10

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AOSE Gaia (1)

• Gaia is a methodology initially proposed by M.
  Wooldridge, N.R. Jennings, and D. Kinny in the
  article ''A methodology for Agent-Oriented
  Analysis and Design'' (1999) 11
• Recently, a new version of Gaia has been proposed
  by M. Wooldridge, N.R. Jennings and Franco
  Zambonelli (3-10-2003) 12.The new version
  extends the range of applications to which Gaia
  can be applied

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AOSE Gaia (2)

• REQUIREMENTS Gaia does not explicitly deal with
  the activities of requirements capturing
• ANALYSIS
• The Organization multiple organizations have to
  co-exist in the system and become autonomous
  interacting MASs (Multi-Agent Systems)
• Environmental Model The environment is modelled
  in terms of abstract computational resources as
  variables or tuples, made available to the agents
  for sensing, for effecting, or for consuming

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AOSE Gaia (3)

• Preliminary Role Model definition of the
  organization's roles and protocols. There are two
  main attribute classes
• Permissions what can or cannot be done while
  carrying out the role
• Responsibilities
• Liveness propertiesgiven centain conditions,
  ''something good happens''
• Safety properties are invariants, '' nothing bad
  happens ''
• Preliminary Interaction Model protocol
  definition for each type of inter-role
  interaction with particular attributes protocol
  name, initiator, partner, inputs, outputs,
  description
• Organizational Rules it is possible to
  distinguish between liveness and safety
  organizational rules.
• Liveness rules define how the dynamics of the
  organization should evolve over time
• Safety rules define time-independent global
  invariants for the organization

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AOSE Gaia (4)

• ARCHITECTURAL DESIGN
• During this engineering stage, various notations
  and graphical representations can be adopted to
  describe and present roles and their interactions
  (e. g., AUML diagrams)
• Completion of Role and Interaction Models
• The identification of the MAS organizational
  structure allows the MAS designer to know which
  roles will interact with other roles and which
  protocols will be followed during interaction

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AOSE Gaia (5)

• DETAILED DESIGN
• Agent Model identifies which agent classes are
  to be defined to play specific roles and how many
  instances of each class have to be instantiated.
• Services Model identifies the services
  associated with each agent class. For each
  service the documentation related to its inputs,
  outputs, pre-conditions and post-conditions must
  be provided
• IMPLEMENTATION Gaia does not deal with
  implementation issues

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AOSE Prometheus (1)

• Prometheus is a methodology proposed by L.
  Padgham and M. Winikoff in the article ''
  Prometheus A methodology for Developing
  Intelligent Agents '' (2002) 13
• Prometheus was the wisest Titan in Greek mythology

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AOSE Prometheus (2)

• SYSTEM SPECIFICATION
• In this stage ''percepts'' and ''actions'' that
  characterize the agent's interaction with the
  environment are defined
• Functional descriptors that contain a name,
  description, actions, percepts, data used, and
  produced and a description of interactions are
  defined
• Use cases contain an identification number, a
  natural language overview, an optional field
  context, the scenario , a summary of all the
  information used, and a list of small variants

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AOSE Prometheus (3)

• ARCHITECTURAL DESIGN
• During this stage the following activities are
  performed
• Identification of which agents should belong to
  the MAS
• identification of groups of agents which share
  the same functionalities
• identification of the agent acquaintance diagram
  which defines the links among interacting agents

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AOSE Prometheus (4)

• definition of the agent descriptors,
  characterized by name, description, cardinality,
  functionalities, reads data, writes data,
  interacts with
• definition of the events, messages and shared
  data objects

- identification of the system overview diagram
which ties together agents, events and shared
data objects - definition of the interaction
diagrams and interaction protocols using AUML
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AOSE Prometheus (5)

• DETAILED DESIGN
• Focuses on developing the internal structure of
  each agent and how it will achieve its task
  within the system
• The developer must define capabilities, internal
  events, plans and detailed data structures
• Capability descriptor contains inputs and
  produced events, a description of functionality,
  a name, interactions with other capabilities,
  inclusions and a reference to read and write data
• Agent overview diagram shows capabilities within
  an agent
• Capability overview diagram takes a single
  capability and describes its features
• The final design artifacts are the individual
  plan, even and data descriptors
• The Plan descriptor provides an identifier, the
  triggering event type, the plan steps, a context
  and a list of data read and written

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AOSE Tropos (1)

• Tropos is a methodology proposed by J.
  Mylopoulos, M. Kolp and P. Giorgini in the
  article '' Agent Oriented Software Development ''
  (2002, but since 2000 was matter of study) 14
• This presentation is based on the latest article
  written by P. Bresciani, P. Giorgini, F.
  Giunchiglia, J. Mylopoulos and A. Perini
  ''TROPOS An Agent-Oriented Software Development
  Methodology '' (May 2004) 15

• FIVE MAIN DEVELOPMENT PHASES
• Early Requirements
• Late Requirements
• Architectural Design
• Detailed Design
• Implementation

NOTE Tropos from Greek ''tropé'' which means
''easily changeable'', also ''easily adaptable''
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AOSE Tropos (2)

• MODELING ACTIVITIES
• Actor modeling, which consists of identifying and
  analyzing both the actors of the environment and
  system' s actors and agents
• Dependency modeling
• Goal modeling based on 3 basic techniques
  means-end analysis, contribution analysis, and
  AND/OR decomposition
• Plan modeling
• Capability modeling

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AOSE Tropos (3)

• EARLY REQUIREMENTS ANALYSIS consists of
  identifying and analyzing the stakeholders and
  their intentions. We must create Actor Diagrams
  and Goal Diagrams

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AOSE Tropos (4)
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AOSE Tropos (5)

• LATE REQUIREMENTS ANALYSIS focuses on the
  system-to-be within its operating environment.
  System-to-be is represented with a goal diagram
  as one actor which has a number of dependencies
  with the other actors of the organization.
• ARCHITECTURAL DESIGN defines the system' s
  global architecture in terms of sub-systems
  (actors) interconnected through data and control
  flows (dependencies). It is articulated in 3
  steps
• Step 1 the overall architecture is defined (
  extended actor diagram)
• Step 2 the capabilities is defined from actor
  dependencies
• Step 3 a set of agent types with one or more
  different capabilities (agent assignment) is
  defined

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AOSE Tropos (6)

• DETAILED DESIGN deals with the specification of
  the agents' micro level
• Capability diagrams model a capability with UML
  activity diagrams. In particular action states
  model plans
• Plan diagrams each plan node of a capability
  diagram can be further specified by UML activity
  diagrams
• Agent interaction diagrams AUML sequence
  diagrams
• IMPLEMENTATION in JACK Intelligent Agents 16,
  an agent-oriented development environment

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Comparison (1)

• In order to compare Agent-Oriented Methodologies
  we must have a comparison framework
• In order to compare Gaia and Tropos we refer to
  the framework presented by A. Sturm and O.
  Shehory in ''A Framework for Evaluating
  Agent-Oriented Methodologies'' 17
• In order to compare Prometheus and Tropos we
  refer to the framework presented by K.H. Dam and
  M. Winikoff in ''Comparing Agent-Oriented
  Methodologies'' 18

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Comparison (2)

• GAIA AND TROPOS
• The Evaluation Framework
• Properties autonomy, reactiveness, pro
  activeness, sociality
• Concepts agent, belief, desire, intention
  message, norm, organization, protocol, role,
  service, Society, task
• Notation and Modeling Techniques properties
  accessibility, analyzability, complexity
  management, executability, expressiveness,
  modularity, preciseness
• Process development context, life cycle coverage
  (requirements, analysis, design, implementation,
  testing)
• Pragmatics resources, required expertise,
  language (paradigm and architecture) suitability,
  domain applicability, scalability
• Metric scale from 1 to 7

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Comparison (3)
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Comparison (4)

• PROMETHEUS AND TROPOS
• The Evaluation Framework
• Concepts agents, autonomy, adaptability, mental
  notions (BDI), relationship, communication,
  goals, agent role, capabilities, percepts,
  actions and events
• Modeling language usability, technical criteria
  ( unambiguity, consistency, traceability)
• Process enterprise modeling, domain analysis,
  requirements analysis, design, implementation and
  testing
• Pragmatic management and technical issues

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Comparison (5)
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Comparison (6)
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Comparison (7)

• PROMETHEUS AND GAIA
• No existing framework
• Gaia stresses the role organization
• Prometheus is more detailed in the definition of
  single agents
• Prometheus adheres to the BDI model, while Gaia
  does not

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Useful link (1)

• http//www.science.unitn.it/recla/aose/
  (contains links to all AOSE methodologies)

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References (1)

• 1 M. Wooldridge, Agent-Based software
  engineering, IEE Proc. Software Engineering 144
  (1) (1997) 26-37.
• 2 G. Booch, Object-Oriented analysis and Design
  with Applications, Addison-Wesley, Reading, MA,
  1994.
• 3 Birgit Burmeister. Models and methodology for
  agent-oriented analysis and design. In K fischer,
  editor, Working Notes of the KI'96 Workshop on
  Agent-Oriented Programming and Distributed
  Systems, 1996. DFKI.
• 4 David Kinny, Michael Georgeff, and Anand Rao.
  Amethodology and modelling techniques for systems
  of BDI agents. In W. van der Velde and J.
  Perrram, editors, Agents Breaking Away
  Proceedings of the Seventh European Workshop on
  Modelling Autonomous Agents in a Multi-agent
  World MAAMAW'96, (LNAI Volume 1038).
  Springer-Verlag Heidelberg, Germany, 1996.

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References (2)

• 5 B. Moulin and L. Cloutier. Collaborative work
  based on multiagent architectures A
  methodological perspective. In Fred Aminzadeh and
  Mohammad Jamshidi, editors, Soft Computing Fuzzy
  Logic, Neural Networks and Distributed Artificial
  Intelligence, pages 261296. Prentice-Hall, 1994.
• 6 Bernard Moulin and Mario Brassard. A
  scenario-based design method and an environment
  for the development of multiagent systems. In D.
  Lukose and C. Zhang, editors, First Australian
  Workshop on Distributed Artificial Intelligentce,
  (LNAI volumen 1087), pages 216231.
  Springer-Verlag Heidelberg, Germany, 1996.
• 7 Elisabeth A. Kendall, Margaret T. Malkoun,
  and Chong Jiang. A methodology for developing
  agent based systems for enterprise integration.
  In D. Luckose and Zhang C., editors, Proceedings
  of the First Australian Workshop on DAI, Lecture
  Notes on Artificial Intelligence.
  Springer-Verlag Heidelberg, Germany, 1996.

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References (3)

• 8 Norbert Glaser. Contribution to Knowledge
  Modelling in a Multi-Agent Framework (the CoMoMAS
  Approach). PhD thesis, L'Universtite Henri
  Poincare, Nancy I, France, November 1996.
• 9Carlos A. Iglesias, Mercedes Garijo, Jose C.
  Gonzalez, and Juan R. Velasco. Analysis and
  design of multiagent systems using
  MAS-CommonKADS. In AAAI'97 Workshop on Agent
  Theories, Architectures and Languages,
  Providence, RI, July 1997. ATAL. (An extended
  version of this paper has been published in
  INTELLIGENT AGENTS IV Agent Theories,
  Architectures, and Languages, Springer Verlag,
  1998.
• 10 Anne Collinot, Alexis Drogoul, and Philippe
  Benhamou. Agent oriented design of a soccer robot
  team. In Proceedings of the Second International
  Conference on Multi-Agent Systems (ICMAS-96),
  pages 4147, Kyoto, Japan, December 1996.
• 11 M. Wooldridge, N. R. Jennings and D. Kinny.
  A Methodology for Agent-Oriented Analysis and
  Design. Proceedings of the 3rd International
  Conference on Autonomous Agents (Agents-99),
  Seattle, WA, 69-76. 1999. http//www.ecs.soton.ac.
  uk/nrj/download-files/aa99.ps

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References (4)

• 12 F.Zambonelli and N.R.Jennings and
  M.Wooldridge,Developing Multiagent Systems The
  Gaia Methodology,ACM Transactions on Software
  Engineering and Methodology, Vol. 12, No. 3,
  2003. http//polaris.ing.unimo.it/Zambonelli/pubbl
  ica.html
• 13 L. Padgham and M. Winikoff. Prometheus A
  Methodology for Developing Intelligent Agents.
  Proceedings of the First Intemational Joint
  Conference on Autonomous Agents and Multi-Agent
  Systems (AAMAS 2002). July, 2002, Bologna, Italy.
  http//goanna.cs.rmit.edu.au/winikoff/Papers/aose
  02.pdf 
• 14J. Mylopoulos, M. Kolp and P. Giorgini. Agent
  Oriented Software Development. Proceedings of the
  2nd Hellenic Conference on Artificial
  Intelligence (SETN-02), April 2002.
  http//dit.unitn.it/tropos/papers_files/hai-jm.pd
  f

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References (5)

• 15 P. Bresciani, P. Giorgini, F. Giunchiglia,
  J. Mylopoulos and A. Perini. TROPOS An
  Agent-Oriented Software Development Methodology.
  In Journal of Autonomous Agents and Multi-Agent
  Systems, Kluwer Academic Publishers Volume 8,
  Issue 3, Pages 203 - 236, May 2004.
  http//dit.unitn.it/tropos/papers_files/jaamas04.
  pdf
• 16 M. Coburn, ''JACK Intelligent Agents User
  Guide,'' AOS Technical Report, Agent Oriented
  Software Pty Ltd, July 2000. http//www.jackagents
  .com/docs/jack/html/index.html.
• 17 Arnon Sturm and Onn Shehory, A Framework for
  Evaluating Agent-Oriented Methodologies, Workshop
  on Agent-Oriented Information System (AOIS),
  Melbourne, Australia, July 14, 2003.
  http//www.technion.ac.il/sturm/
• 18 Khanh Hoa Dam, Michael Winikoff, Comparing
  Agent-Oriented Methodologies, to appear in the
  proceedings of the Fifth International
  Bi-Conference Workshop on Agent-Oriented
  Information Systems to be held in Melbourne in
  July (at AAMAS03). http//www.cs.rmit.edu.au/agent
  s/Papers/aois2003.pdf

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AOSE Gaia

• Organizational Rules the notation
• The notation for each type is the temporal logic
  formalism.
• There is an alternative approach
• For liveness properties based on regular
  expressions
• For safety requirements based on constrains over
  the variable listed in a role' s permissions
  attribute