Multiagent SystemsAgent Oriented Software Engineering

Viviana Mascardi

viviana.mascardi@unige.it

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Outline

1 Introduction

2 Agent-Oriented Architectures

3 AOSE methodologies

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Introduction

Introduction

F. Zambonelli, A. Omicini. Challenges and Research Directions inAgent-Oriented Software Engineering. Journal of AutonomousAgents and Multi-Agent Systems, 9(3), pp. 253-283, 2004P. Giorgini, B. Henderson-Sellers. Agent-Oriented Methodologies:An Introduction. In Agent-Oriented Methodologies. December2004 - January 2005. P. Giorgini and B. Henderson-Sellers (Eds.)

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Introduction

Introduction

The features of agent-based systems are well suited to tackle thecomplexity of developing software in modern scenarios:

1 the autonomy of application components reflects the intrinsicallydecentralised nature of modern distributed systems and can beconsidered as the natural extension to the notions of modularityand encapsulation for systems that are owned by differentstakeholders;

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Introduction

Introduction

2 the flexible way in which agents operate and interact (both witheach other and with the environment) is suited to the dynamic andunpredictable scenarios where software is expected to operate;

3 the concept of agency provides for a unified view of AI results andachievements, by making agents and MASs act as sound andmanageable repositories of intelligent behaviours.

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Introduction

Introduction

In the last few years, together with the increasing acceptance ofagent-based computing as a novel software engineeringparadigm, there has been a great deal of research related to theidentification and definition of suitable models and techniques tosupport the development of complex software systems in terms ofMASs.This research, can be roughly grouped under the termAgent-Oriented Software Engineering (AOSE).

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Introduction

The Promise of AOSE for distributed systemsengineering

Today’s software engineering approaches are increasinglyadopting abstractions approaching that of agent-based computing.This trend can be better understood by recognising that the vastmajority of modern distributed systems scenarios are intrinsicallyprone to be developed in terms of MASs, and that moderndistributed systems are already de facto MASs, i.e., they areindeed composed of autonomous, situated, and socialcomponents.

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Introduction

The Promise of AOSE for distributed systemsengineering: Autonomy

As far as autonomy is concerned, almost all of today’s softwaresystems already integrate autonomous components.At its weakest, autonomy reduces to the ability of a component toreact to and handle events, as in the case of graphical interfacesor simple embedded sensors.However, in many cases, autonomy implies that a componentintegrates an autonomous thread of execution, and can execute ina proactive way.

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Introduction

The Promise of AOSE for distributed systemsengineering: Situatedness

Today’s computing systems are also typically situated.For example, control systems for physical domains and sensornetworks, are built to explicitly manage data from the surroundingphysical environment, and take into account the unpredictabledynamics of the environment.Mobile and pervasive computing applications recognise (under thegeneral term of context-awareness) the need for applications tomodel explicitly environmental characteristics and data.Internet applications are also conceived for being aware of thefeatures and the dynamics of the environment where they work,namely, the Web.

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Introduction

The Promise of AOSE for distributed systemsengineering: Sociality

Sociality in modern distributed systems comes in different flavors:1 the capability of components of supporting dynamic interactions,

i.e., interaction established at run-time with previously unknowncomponents;

2 the somewhat higher interaction level, overcoming the traditionalclient-server scheme;

3 the enforcement of some sorts of societal rules governing theinteractions.

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Introduction

The Promise of AOSE for intelligent systemsengineering

Artificial Intelligence is mainly concerned with building intelligentsystems: the very name of “Artificial Intelligence” literally suggeststhe notion of artifacts exhibiting intelligent behaviour.Therefore, AI can be considered as an engineering field (dealingwith constructive concerns), rather than simply a scientific one(dealing with understanding and predicting intelligent systemsbehaviour).

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Introduction

The Promise of AOSE for intelligent systemsengineering

As already seen in the previous lessons, nearly 30 years of AIresearch were conducted by having research groups concentrateon single, isolated aspects of AI (like, say, artificial vision,knowledge representation, planning).There were few attempts of producing a reasonable set ofconceptual and practical tools, which could promote theintegration of such a vast amount of research findings into themainstream practice of software development.This is where agents are actually becoming a key abstraction intoday’s AI.

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Introduction

The Promise of AOSE for intelligent systemsengineering

The very notion of agents provides a uniform conceptual spacewhere all the findings of the AI field can be easily framed andrelated, and eventually find mainstream acceptance.

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Introduction

Current directions in AOSE

Mainstream research directions in AOSE:1 Agent-Oriented Architectures2 AOSE methodologies3 Notation techniques4 Agent-Oriented Programming Languages5 Agent-based Modeling and Simulation6 MAS infrastructures

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Introduction

Current directions in AOSE

Mainstream research directions in AOSE:1 Agent-Oriented Architectures (in this lesson)2 AOSE methodologies (in this lesson)3 Notation techniques (after lessons on communication)4 Agent-Oriented Programming Languages (lessons on Jason)5 Agent-based Modeling and Simulation (lessons on NetLogo)6 MAS infrastructures (lessons on JADE)

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Agent-Oriented Architectures

Outline

1 Introduction

2 Agent-Oriented Architectures

3 AOSE methodologies

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Agent-Oriented Architectures

Acknowledge

For this part of the lesson we will use the slides by Antonio Moreno, inturn based on Rosenschein’s slides from Wooldridge book. They canbe downloaded from https://www.slideshare.net/ToniMorenoURV/agent-architectures-3181662

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Agent-Oriented Architectures

But this wonderful picture is by myself!!!

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AOSE methodologies

Outline

1 Introduction

2 Agent-Oriented Architectures

3 AOSE methodologies

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AOSE methodologies

Genealogy of some AOSE methodologies

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AOSE methodologies

Gaia

Wooldridge, M., Jennings, N.R. and Kinny, D. The GaiaMethodology for Agent-Oriented Analysis and Design.Autonomous Agents and Multi-Agent Systems (2000)3(3):285–312.Franco Zambonelli, Nicholas R. Jennings, and MichaelWooldridge. 2003. Developing multiagent systems: The Gaiamethodology. ACM Trans. Softw. Eng. Methodol. 12, 3 (July2003), 317-370.

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AOSE methodologies

Reminder: what is a MAS

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AOSE methodologies

Acknowledge

For this part of the lesson we will use the slides by Mehdi Dastani,“Multi-Agent Programming Software Development Methodologies forMulti-Agent Systems”. They can be downloaded fromhttp://www.cs.uu.nl/docs/vakken/map/slides/gaia.pdf

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AOSE methodologies

Prometheus (further example, not part of the program)

L. Padgham and M. Winikoff. Prometheus: A Methodology forDeveloping Intelligent Agents. In Proceedings of the ThirdInternational Workshop on Agent-Oriented Software Engineering(AOSE 2002), at AAMAS’02, 2002.L. Padgham and M. Winikoff. Developing Intelligent AgentSystems: A Practical Guide. 2004, John Wiley and Sons.L. Padgham, J. Thangarajah, and M. Winikoff. Tool Support forAgent Development using the Prometheus Methodology. InProceedings of the First International Workshop on Integration ofSoftware Engineering and Agent Technology (ISEAT 2005), 2005.The Prometheus Design Tool:http://www.cs.rmit.edu.au/agents/pdt/.

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AOSE methodologies

Prometheus

The Prometheus methodology consists of three phases.1 The system specification phase focuses on identifying the basic

functionalities of the system, along with inputs (percepts), outputs(actions) and any important shared data sources.

2 The architectural design phase uses the outputs from the previousphase to determine which agents the system will contain and howthey will interact.

3 The detailed design phase looks at the internals of each agentand how it will accomplish its tasks within the overall system.

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AOSE methodologies

Prometheus

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AOSE methodologies

Prometheus: System Specification

This phase consists of the following steps, which are interleaved anditerated until the specification is considered sufficiently complete

1 Identification of actors and their interactions with the system, inthe form of percepts and actions;

2 Developing scenarios (by means of use cases) illustrating thesystem’s operation;

3 Identification of the system goals and sub-goals;4 Identifying any external data;5 Grouping goals and other items into the basic roles of the system.

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AOSE methodologies

Prometheus: Architectural Design

This phase uses artefacts produced in the System Specification Phaseto determine what agent types will be included in the system and theinteraction between these agents. The steps in this phase are:

1 Determine the agent types2 Develop the interaction protocols3 Develop the system overview diagram

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AOSE methodologies

Prometheus: Detailed Design

This phase uses artefacts produced in the Architectural Design Phaseto define the internals of every agent in the system and to specify howagents accomplish their overall tasks.

Each agent is refined in terms of its capabilities, internal events,plans, and data structures.Each capability has a capability overview diagram that capturesthe structure of the plans within this capability and the events thatare associated with these plans.The dynamic behaviour is described by process diagrams basedon the interaction protocols identified in the previous phase.

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AOSE methodologies

Prometheus: a running example

We will go through the design and implementation of a small librarymanagement system. This system should be able to do the followingthings:

Allow for checkout of books, providing a return date to thecustomerAllow for return of booksAllow for reservation of unavailable booksAllow for notification of overdue booksAllow for notification of arrival of reserved books

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AOSE methodologies

System specification: Goals and subgoals

Checkout books– Record book code to the user id checked out list.– Provide return date.Return books– Remove book code from the user idReserve unavailable books– Record book code as reserved for user id– Show the current due date for the book

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AOSE methodologies

System specification: Goals and subgoals

Give notification for overdue books– Access book record at the start of the day– Send email for overdue booksGive notification of arrival of reserved books– Access the reserved list for user– Send email notification

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AOSE methodologies

System specification: Goals and subgoals

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AOSE methodologies

System specification: Goals and subgoals

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AOSE methodologies

System specification: Goals and subgoals

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AOSE methodologies

System specification: Scenarios

Depending on the system we can identify 5 different scenarios1 When the user comes to checkout the book.2 When the user returns the book.3 When a book becomes overdue.4 When the user asks to reserve a book.5 When the reserved book arrives.

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AOSE methodologies

System specification: Scenarios

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AOSE methodologies

System specification: Checkout scenario

1 Request for checkout2 Provide return date3 Record book code as checked out4 Provide book

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AOSE methodologies

System specification: Return scenario

1 Book returned2 Remove book code from checkout list

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AOSE methodologies

System specification: Reserve scenario

1 Request for reservation2 Record book code as reserved3 Show current due date4 Provide current due date

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AOSE methodologies

System specification: Arrival scenario

1 Reserved book arrives2 Find the reserved user3 Send arrival email

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AOSE methodologies

System specification: Overdue scenario

1 Start of the day2 Find overdue books at the start of the day3 Send overdue email

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AOSE methodologies

System specification: Role grouping

1 Checkout books2 Return books3 Overdue books4 Reserve books5 Send Arrival Notification

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AOSE methodologies

System specification: Checkout books role

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AOSE methodologies

System specification: Return and overdue books roles

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AOSE methodologies

System specification:Reserve books and send arrival notification roles

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AOSE methodologies

Architectural design: Data coupling

In this phase we need to identify what type of data need to be stored inthe system as beliefs. In our running example, we need to keep theinformation of all books that have been checked out and also thebooks that have been reserved

The checkout books role and return books role update thecheckout belief and the overdue books role uses this to sendoverdue email.The reserve books role updates the reserve belief and the arrivalnotification uses it.

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AOSE methodologies

Architectural design:Data coupling for checkout role

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AOSE methodologies

Architectural design:Data coupling for reserve role

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AOSE methodologies

Architectural design: Agent-role coupling

Now we group the roles and identify three agents to carry out this rolesin the system. The agents identified are:

Checkout AgentReservation AgentOverdue Agent

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AOSE methodologies

Architectural design: Checkout agent-role coupling

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AOSE methodologies

Architectural design: Reservation agent-role coupling

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AOSE methodologies

Architectural design: Overdue agent-role coupling

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AOSE methodologies

Architectural design: Agent acquaintance diagram

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AOSE methodologies

Architectural design: System overview diagram

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AOSE methodologies

Detailed design: Capabilities of the checkout agent

Checkout CapabilityReturn CapabilityGet Return Date Capability

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AOSE methodologies

Detailed design: Capabilities of the checkout agent

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AOSE methodologies

Detailed design: Checkout plan

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AOSE methodologies

Detailed design: Return plan

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AOSE methodologies

Detailed design: Get return date plan

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AOSE methodologies

Detailed design: Capabilities of the reservation agent

Reservation CapabilityArrival Notification Capability

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AOSE methodologies

Detailed design: Capabilities of the reservation agent

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AOSE methodologies

Detailed design: Reservation plan

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AOSE methodologies

Detailed design: Arrival notification plan

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AOSE methodologies

Detailed design: Capabilities of the overdue agent

Find overdue books Capability

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AOSE methodologies

Detailed design: Find overdue books plan

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