A Knowledge Level Software Engineering Methodology for Agent

A Knowledge Level Software Engineering Methodology for Agent Oriented Programming The Tropos framework Fausto Giunchiglia Dept. of Information and Communication Technology University of Trento SRA Division ITC irst Trento fausto@itc. it - http: //sra. itc. it ATAL - Seattle, August 1 st, 2001 1

Outline • • • – – – Key ideas Modeling language case study metamodel Transformational approach case study revisited transformation operators composition of transformations: intuitions Conclusion Future work Related work ATAL - Seattle, August 1 st, 2001 2

Key ideas ATAL - Seattle, August 1 st, 2001 3

Key ideas The Tropos framework rests on three key ideas: 1. Consider the overall software development process, from early requirements down to implementation 2. Use the notion of agent and all the related mentalistic notions in all phases of software development 3. Adopt a transformational approach, namely perform refinement steps, inside one phase or between phases, using a set of transformation operators ATAL - Seattle, August 1 st, 2001 4

Key ideas (1. 1) 5 phases: • Early requirements • Late requirements • Architectural design • Detailed design • Implementation ATAL - Seattle, August 1 st, 2001 5

Key Ideas (1. 2): AOSE approaches Development process methodologies, organizational analysis ontology Extension of OO specification languages - methodologies MSEM, Wood et al. AAII, Kinny et al. AUML, Odell et al. Gaia, Wooldridge, et al. Tropos ly m ar uire E q re e s nt te r La qui re em e s nt al r ctu te hi n c Ar sig de d ile a et ign D s de n io at t en m e pl Im ATAL - Seattle, August 1 st, 2001 6

Key ideas (2. 1) – we adopt a requirements drivensoftware development approach, exploiting goal analysis and actor dependencies analysis techniques (i* by E. Yu, NFR by Chung et al. , Kaos by Dardenne et al. ) Model the what, how and the why ATAL - Seattle, August 1 st, 2001 7

Key ideas (2. 2) Filling the gap i Agent oriented programming * ts ts en ly ar uir E q re em te r La qui re em en l ra tu c ite h rc ign A s de d ile a et ign D s de n io at t pl Im en m e ATAL - Seattle, August 1 st, 2001 8

Key ideas (2. 3) • Notions of agent and goal are used along all the development phases. • The key elements and dependencies describing the organizational setting can be used to and motivate design and implementation choices. Each artifact (including code) can be retraced back to the analysis performed during requirement phases. • There is a direct and natural correspondence between requirement analysis (social actors) and implemented code (software agents). ATAL - Seattle, August 1 st, 2001 9

Key ideas (3. 1) We adopt a transformational approach: • start with a limited list of Tropos conceptual elements (actors, goals, softgoals, . . . ) • iteratively and incrementally: – add details – revise dependency relationships Each step corresponds to the introduction/deletion of relationships/elements in the model. ATAL - Seattle, August 1 st, 2001 10

Key ideas (3. 2) Advantages of the approach : • provides systematic description of the process • allows for process analysis • provides guidelines to the engineer • provides a sound basis for describing and evaluating requirement acquisition and design strategies ATAL - Seattle, August 1 st, 2001 11

Modeling language ATAL - Seattle, August 1 st, 2001 12

Modeling language case study ATAL - Seattle, August 1 st, 2001 13

The e. Culture system case study • a web-based broker of cultural information and services for the province of Trentino • usable by a variety of users (e. g. Trentinos, tourists, scholars and students). ATAL - Seattle, August 1 st, 2001 14

The e. Culture system case study … following the 5 phases of the Tropos framework • Early requirements • Late requirements • Architectural design • Detailed design • Implementation Tropos social actors Agents ATAL - Seattle, August 1 st, 2001 15

Early requirements Main activities We analyze the environment (i. e. existing organizational setting) and model it in terms of relevant actors and their respective dependencies ATAL - Seattle, August 1 st, 2001 16

Early requirements The stakeholders of the e. Culture domain Citizen Museum PAT Visitor ATAL - Seattle, August 1 st, 2001 17

Early requirements The stakeholders of the e. Culture domain get cultural information Citizen Museum PAT increase internet use Visitor enjoy visit ATAL - Seattle, August 1 st, 2001 18

Early requirements The stakeholders of the e. Culture domain get cultural information Citizen taxes well spent Museum PAT increase internet use Visitor enjoy visit ATAL - Seattle, August 1 st, 2001 19

Early requirements The stakeholders of the e. Culture domain ATAL - Seattle, August 1 st, 2001 20

Early requirements Balloon: goal-decomposition and Means-ends analysis for PAT ATAL - Seattle, August 1 st, 2001 21

Late requirements Main activities We introduce the system actor and analize its dependencies with actors in its environment identifying system’s functional and non-functional requirements ATAL - Seattle, August 1 st, 2001 22

Late requirements Rationale diagram for e. Culture System ATAL - Seattle, August 1 st, 2001 23

Revision of dependencies Early Requirements revised get cultural information Citizen e. Culture sys. available get cultural information e. Culture System PAT e. Culture sys. available ATAL - Seattle, August 1 st, 2001 24

Late requirements dependencies with environmental actors ATAL - Seattle, August 1 st, 2001 25

Architectural design Main activities 3 steps: 1. decomposing and refining the system actor diagram … at three different levels of abstraction 2. identifying capabilities 3. from actors to agents ATAL - Seattle, August 1 st, 2001 26

Architectural design: step 1 a: inclusion of new actors due to delegation of subgoals upon goal analysis of system's goals b: inclusion of new actors according to the choice of a specific architectural style (design patterns) c: inclusion of new actors contributing positively to the fulfillment of some Non Functional Requirements ATAL - Seattle, August 1 st, 2001 27

Architectural design (step 1) taking into account functional requirements : decomposition into sub-actors ATAL - Seattle, August 1 st, 2001 28

Architectural design: step 1 a: inclusion of new actors due to delegation of subgoals upon goal analysis of system's goals b: inclusion of new actors according to the choice of a specific architectural style (design patterns) c: inclusion of new actors contributing positively to the fulfillment of some Non Functional Requirements ATAL - Seattle, August 1 st, 2001 29

Architectural design (step 1) extending actor diagram taking into account architectural styles the Info Broker ATAL - Seattle, August 1 st, 2001 30

Architectural design Step 2 identifying actor capabilities from the analysis of dependencies in the actor diagram …an intuitive idea of the process ATAL - Seattle, August 1 st, 2001 31

Architectural design (step 2) Actor capabilities ATAL - Seattle, August 1 st, 2001 32

Architectural design (step 2) Actor capabilities Actor Name Area Classifier Capability # 1) Get area specification form 2) Classify area 3) Provide area information 4) Provide service description ATAL - Seattle, August 1 st, 2001 33

Architectural design (step 2) Actor capabilities Actor Name Capability # Area Classifier 1) 2) 3) 4) Get area specification form Classify area Provide area information Provide service description Info Searcher 5) 6) 7) 8) 9) Get area information Find information source Compose query Query source Provide query information Provide service description Results Synthesizer 10) 11) 12) 13) Get query information Get query results Provide query results Synthesize area query results Provide service description Sources Interface Manager 14) Wrap information source User Interface Manager 15) 16) 17) 18) Get user specification Provide user specification Get query results Present query results to the user Provide service description ATAL - Seattle, August 1 st, 2001 34

Architectural design Step 3 from actors to agents …. ATAL - Seattle, August 1 st, 2001 35

Architectural design (step 3) from actors to agents Actor Name Capability # Area Classifier 1) 2) 3) 4) Get area specification form Classify area Provide area information Provide service description Info Searcher 5) 6) 7) 8) 9) Get area information Find information source Compose query Query source Provide query information Provide service description Results Synthesizer 10) 11) 12) 13) Get query information Get query results Provide query results Synthesize area query results Provide service description Sources Interface Manager 14) Wrap information source User Interface Manager 15) 16) 17) 18) Get user specification Provide user specification Get query results Present query results to the user Provide service description ATAL - Seattle, August 1 st, 2001 36

Architectural design (step 3) from actors to agents Agent Name Capability # Query Handler 1) Get area specification form 3) Provide area information 4) Provide service description 5) Get area information 7) Compose query 8) Query source 9) Provide query information 10) Get query information 11) Get query results 12) Provide query results Classifier 2) Classify area 4) Provide service description Searcher 4) Provide service description 6) Find information source Synthesizer 13)Synthesize area query results 14)Provide service description User Interface Agent 15, 16, 17, 18, 4 Wrapper 14, 4 ATAL - Seattle, August 1 st, 2001 37

Detailed design Main activities Specification of the agents’ micro level taking into account the implementation platform. Objective: to perform a design that will map directly to the code. We consider a BDI multiagent platform, so … ATAL - Seattle, August 1 st, 2001 38

Detailed design BDI platform case We model: • capabilities – capability diagrams (currently AUML activity diagrams) ATAL - Seattle, August 1 st, 2001 39

Detailed design Capability diagram ATAL - Seattle, August 1 st, 2001 40

Detailed design BDI platform case We model: • capabilities – capability diagrams (currently AUML activity diagrams) • plans – plan diagrams (currently AUML activity diagrams ATAL - Seattle, August 1 st, 2001 41

Detailed design Plan diagram - plan evaluate query ATAL - Seattle, August 1 st, 2001 42

Detailed design BDI platform case We model: • capabilities – capability diagrams (currently AUML activity diagrams) • plans – plan diagrams (currently AUML activity diagrams • agents interaction – agent interactions diagrams (currently AUML sequence diagrams ATAL - Seattle, August 1 st, 2001 43

Detailed design Agent interaction diagram ATAL - Seattle, August 1 st, 2001 44

Implementation Main activities … follow step by step the detailed design specification … In JACK (BDI multiagent platform) agents are autonomous software components that have explicit goals (desires), events to handle, beliefs and capabilities. Agents are programmed with a set of plans that make them capable of achieving goals. ATAL - Seattle, August 1 st, 2001 45

Implementation Jack Intelligent system, AOS ATAL - Seattle, August 1 st, 2001 46

Modeling Language Metamodel ATAL - Seattle, August 1 st, 2001 47

Modeling language So far only for early and late requirement diagrams Tropos conceptual entities (actors, goals, …) are instances of classes in a (meta)metamodel described by UML class diagrams. ATAL - Seattle, August 1 st, 2001 48

Metamodel Entity ATAL - Seattle, August 1 st, 2001 49

Metamodel N-ary Relatioship ATAL - Seattle, August 1 st, 2001 50

Metamodel Actor ATAL - Seattle, August 1 st, 2001 51

Metamodel Goal ATAL - Seattle, August 1 st, 2001 52

Metamodel Plan ATAL - Seattle, August 1 st, 2001 53

Transformational approach ATAL - Seattle, August 1 st, 2001 54

Case study revisited: early requirements again taxes well spent get cultural information citizen PAT e. Culture sys. available 3 get cultural information 4 1 visit cultural institution e. Culture sys. available buy e. Culture system build e. Culture system 5 visit web site 7 2 interenet available e. Culture sys. available provide e. Cult. services good services 6 8 good cultural services ATAL - Seattle, August 1 st, 2001 55

Transformational operators ATAL - Seattle, August 1 st, 2001 56

Composition of operators: intuitions taxes well spent citizen PAT e. Culture sys. available 6 get cultural information 7 4 visit cultural institution buy e. Culture system visit web site taxes well spent 8 provide e. Cult. services 1 5 interenet available build e. Culture system e. Culture sys. available good services 3 2 good cultural services ATAL - Seattle, August 1 st, 2001 57

Composition of operators: intuitions • Different transformation sequences may have different chances to lead to a satisfactory design; • even when the same design is obtained, different transformation sequences in the design process may lead at discovering/facing/discarding relevant elements at different times; • different analyses may have different costs; • balancing analysis costs and good results is a hard (human) planning task. ATAL - Seattle, August 1 st, 2001 58

Conclusion ATAL - Seattle, August 1 st, 2001 59

Conclusion The Tropos framework is a novel approach in Agent Oriented Software Engineering, resting on the following 3 key ideas: – the Tropos approach framework spans the overall software development process, from early requirements down to implementation – we use the notion of agent and all the related mentalistic notions in all phases of software development – we adopt a transformational approach, i. e. , we perform refinement steps, inside one phase or between phases, using a set of transformation operators ATAL - Seattle, August 1 st, 2001 60

Related work ATAL - Seattle, August 1 st, 2001 61

Related work 1) 2) 3) AOSE OOP Requirement engineering ATAL - Seattle, August 1 st, 2001 62

Future work ATAL - Seattle, August 1 st, 2001 63

Future work • Formal Tropos • Architectural patterns • Formalization of the transformational approach (primitives and strategies) ATAL - Seattle, August 1 st, 2001 64

The Tropos group Fausto Giunchiglia, Paolo Giorgini, Fabrizio Sannicoló University of Trento, Trento Paolo Bresciani, Anna Perini, Marco Pistore, Paolo Traverso SRA Division at ITC-IRST, Trento John Mylopoulos, Eric Yu, Manuel Kolp, Luiz Cysneiros, Ariel D. Fuxman, Daniel Gross, Linda Lin University of Toronto, Toronto Yves Lespérance York University, Toronto Jaelson Castro Universidade Federale de Pernambuco, Recife, Brazil ATAL - Seattle, August 1 st, 2001 65

The Tropos framework where to find what I talked about [1] A. Perini, P. Bresciani, F. Giunchiglia, P. Giorgini and J. Mylopoulos, A Knowledge Level Software Engineering Methodology for Agent Oriented Programming. Proc. ACM Int. Conf. Agents 2001 [2] P. Bresciani, A. Perini, P. Giorgini, F. Giunchiglia, J. Mylopoulos, Modeling early requirements in Tropos: a transformation based approach. AOSE workshop at Conf. Agents 2001, LNAI Lectures Notes [3] P. Giorgini, A. Perini, J. Mylopoulos, F. Giunchiglia, P. Bresciani. Agent Oriented Software Development: A Case Study. Proc. Int. Conf. on Software Engineering & Knowledge Engineering (SEKE 01), 2001 [4] A. Fuxman, M. Pistore, J. Mylopoulos, P. Traverso. Model Checking Early Requirements Specifications in Tropos. IEEE Int. Symp. on Requirements Engineering, 2001 [5] M. Kolp, P. Giorgini, J. Mylopoulos. A Goal Based Organizational Perspective on Multi Agent Architectures. Int. Workshop ATAL-2001, LNAI Lecture notes ATAL - Seattle, August 1 st, 2001 66