Goal, role, and domain modelling as the front end for designing distributed systems Dr Kuldar Taveter, The University of Melbourne

Brave, New World Many computing nodes Peer-to-peer interactions Openness Change Uncertainty Unpredictability

Socio-technical system A system that includes hardware and software and people A system that contains both a social aspect, which may be a subsystem, and a technical aspect

The forthcoming book ‘The Art of Agent-Oriented Modelling’ by Leon Sterling and Kuldar Taveter To be published in the second half of 2008 by MIT Press

The conceptual space

Motivation layer

What is a goal? A particular state of affairs intended Dream with a deadline

Two kinds of goals Functional goal: a goal that captures one or more desired scenarios. Example: listen to the seminar talk, forgive each other. Quality goal: quality requirement of the achievement of the functional goal. Example: listen to the seminar talk attentively, forgive each other seventy times seven times.

What is a role? Some capacity or position within the system to facilitate the achievement of its goal

What is a social policy? A constraint on the achievement of a goal within an organization Examples: tipping, bringing flowers to a wedding ceremony, handling business cards with two hands

System design layer

Deployment layer

Relationships between the concepts

Types of models at different layers Motivation layer: goal models, role and organisation models, domain models System design layer: agent and acquaintance models, interaction models, scenarios, behaviour models, service models Deployment layer: agent interface and interaction specifications, data models, agent behaviour specifications, service specifications

Case studies Conference management system Air traffic control Tamagotchis Smart home B2B e-commerce Manufacturing

The case study of a conference management system Paper submission Reviewing Reminders Notifications Submission of camera-ready versions Printing

The goal model for a conference management system

The goal model for selecting reviews

The role model for Author

The role model for PC Chair Role namePC Chair DescriptionThe PC Chair manages the process of determining the technical program for the conference. ResponsibilitiesInvite PC members. Receive confirmations of acceptance from PC members. Register PC members. Advertise the conference. Decide submission deadlines. Decide submission format. Receive the papers for the conference. -Store the papers. -Assign submission numbers to the papers. -Confirm paper submissions with the authors. Interact with PC members to receive their reviewing preferences. Assign the papers to PC members for reviewing. Re-distribute the papers rejected for review. Receive the reviews done by PC members. Negotiate with PC members about borderline or conflicting papers. Make acceptance/rejection decisions on the papers. Notify the authors of the acceptance/rejection decisions. Send the reviews to the authors. Request and receive final versions of the accepted papers. Request the publisher to print the final versions of the accepted papers as the proceedings of the conference. Submit the final proceedings to the publisher according to an agreed deadline. ConstraintsEach paper must be distributed to at least three PC members for reviewing. There is a limit in the number of papers that a PC chair can review. A PC member cannot review his/her own paper. A PC member cannot review a paper with which he/she has a conflict of interest. The authors must be notified in a timely manner whether their paper has been accepted or rejected. The submissions of final versions of the accepted papers to the publisher must be complete, with all the accepted papers included.

The organisation model for a conference management system

The interaction frame diagram for roles

Domain model Domain model represents the knowledge within the system that the system is supposed to handle. A domain model may represent the environment(s) in which the system is to be situated and the resources provided by the environment(s).

The domain model for a conference management system

Quality Standard of excellence (quality sign) Being fit for purpose. Examples: quality standards and McDonald’s hamburgers. Quality as an attribute Speed, reliability, scalability, maintainability, but also having fun, being secure, etc.

Measurable or not? Some quality goals are quantifiable. For example: performance targets or system availability. Qualitative descriptions are often more intuitive for stakeholders. For example: system being secure, game being fun, forgiving seventy times seven times.

Qualitative analysis Achievement of quality goals depends on the context. Analysis at the motivation layer Analysis of how quality goals affect design decisions

The goal model for the allocation of airport resources

The goal model for local ATC

From requirements analysis to design

Simulation

Conclusions Clear diagrams The models facilitate communication between software engineers and stakeholders & domain experts. The models can be straightforwardly turned to various design models and prototype applications. The models are ontologically founded.

The case study of Tamagotchis

The goal model for a system of humans and Tamagotchis

The motivational scenario of playing with a Tamagotchi

The role model for MyTamagotchi Role nameMyTamagotchi DescriptionThe role of my digital pet. Responsibilities Grow from baby to child to teenager to adult. Express hunger. Become sick. Produce excrement. Express loneliness. Misbehave occasionally: -express hunger when not hungry; -refuse food when hungry; -present a friend with an inappropriate gift. Visit the friend. Give the friend a present. Play with the friend. Constraints The present needs to be appropriate. Only the initiator can give a present. The higher the level of training, the less the Tamagotchi misbehaves. The Tamagotchi needs to be of appropriate age to play with certain items. The Tamagotchi must be of the appropriate age to go to pre-school or school. The Tamagotchi must graduate from school to go to work. The Tamagotchi must have a sufficient amount of “gotchi” points to buy something from the shopping mall, food court, or travel agency. The Tamagotchi must have donated a certain number of “gotchi” points to visit the king’s castle.

The role model for Owner Role nameOwner DescriptionThe role of the owner of my digital pet. Responsibilities Wake up the Tamagotchi. Feed the Tamagotchi. Cure the Tamagotchi. Flush the toilet. Discipline the Tamagotchi. Play a game with the Tamagotchi. Let the Tamagotchi play with an item. Initiate an interaction with another Tamagotchi: Visit Tamagotchi Town with the Tamagotchi: -take the Tamagotchi to pre-school; -take the Tamagotchi to school; -take the Tamagotchi to workplace; -take the Tamagotchi to theatre; -take the Tamagotchi to shopping mall; -take the Tamagotchi to food court; -take the Tamagotchi to travel agency; -take the Tamagotchi to the game centre; -take the Tamagotchi to the town hall; -take the Tamagotchi to the king’s castle. Constraints For interacting with another Tamagotchi, the owner needs to establish infrared connection with correct parameters between the two Tamagotchis. To visit Tamagotchi Town, the owner must have a computer with Internet connection.

The organisation model for Tamagotchis

The domain model for the case study of Tamagotchis

The types of resources consumed by a Tamagotchi