1. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution1 Signs of a Revolution in Computer Science and Software Engineering Franco Zambonelli & Van Parunak University of Modena and Reggio Emilia, Italy Altarum, USA

2. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution2 Outline What’s new in today’s software systems? –situatedness –openness –local control –local interactions The role of agents How will this affect research & practice? –impact in computer science –impact in software engineering From design to intention….

3. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution3 Towards a New Software Crisis Not only a change in size There are also qualitative changes in the way software is built and execute –pervasive changes, affecting several areas –challenging current approaches and techniques to software modeling and development Contribution of this work –identifying the new characteristics of software systems  ubiquity of agent-based concepts –outline their impact on CS and SE So, WHAT’S NEW?

4. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution4 What’s New? Situatedness Openness Locality in Control Locality in Interactions

5. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution5 Situatedness Components execute and interact in an environment –traditional approaches tend to mask (or wrap) the presence of the environment The environment impacts on modeling and execution –interactions too complex to enable simple wrappings –applications may be explicitly devoted to model a real-world physical environment –the environment can have its own dynamics, leading to unpredictability and non-determinism Need of explicit notion of environment –defining the boundaries –and the dynamic interactions across the boundaries

6. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution6 Examples Embedded control systems for physical domains –health care, traffic control, manufacturing control –explicit representation of environmental data and events Internet applications –components interact with existing services and applications –middleware as the substrate modelling the environment –middleware define the boundaries of an application CSCW systems –explicit abstraction of “workplace” –agents execute and interact in that workplace Ant-based optimisation systems –ants immersed in the environment –interactions influenced by the environment dynamics

7. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution7 What’s New? Situatedness Openness Locality in Control Locality in Interactions

8. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution8 Openness Living in an environment and being influenced by it implies openness…moreover…. Defining the boundaries of a system may be difficult –interaction may be so complex to make it unclear what is in and what is out –system interacting directly with each other and with the mediation of the environment –boundaries may vary in time, components may go in and out Dynamic systems, other than dynamic environments –openness intended as the dynamic changes in systems and in boundaries Need of modeling “context” –context-dependency –context awareness

9. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution9 Examples Critical control systems –cannot be stopped –updated and incremented with new components at run-time Internet computing –new sites, components, and services added and destroyed continuously –running applications enriched on-line –virtual mobility of components in agoras (e.g. auction sites) Mobile computing –explicit movement across different environments –entering new systems and meeting new components –context-awareness a primary research topics

10. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution10 What’s New? Situatedness Openness Locality in Control Locality in Interactions

11. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution11 Locality in Control Applications and systems with multiple independent flows of control  control embedded in components Also in traditional concurrent computing, BUT –the key issue was to still maintain a single centre of control Today, multiple autonomous flow of control intended as autonomous centres of control –autonomy facilitates the execution of components in dynamic and unpredictable environments –delegation of control can make application design simpler, especially in the case of large applications –computer-based systems and mobile systems can be modelled as autonomous components

12. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution12 Examples Almost of of today’s computing systems and applications integrate autonomous components –proactive sensors and actuators in control systems –daemons and personal agents in the Internet –PDAs, cellular phones, as well as any mobile device… The problem is: –recognising autonomy in these –other than simply concurrency

13. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution13 What’s New? Situatedness Openness Locality in Control Locality in Interactions

14. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution14 Locality in Interactions Somehow deriving from the previous three –still worth an independent analysis Interactions with the environment are local –for physical reasons –for the sake of conceptual simplicity (we cannot think at handling all the world) Interactions are local to a context –systems moving and entering different systems –and interacting within that systems Scalability requires locality –also due to autonomy

15. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution15 Examples Control systems for physical domains –delegate to control local portions of an environment (logical or physical) –coordinating actions with other local components Internet computing –concept of virtual mobility (network-aware navigation) –interactions in a site, domain of sites (e.g., Jini locality of services and of look-ups) Mobility –physical laws determines the locality scope of interactions –the concept of “context” in in any case strictly enforced

16. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution16 The Role of Agents Agents are : –situated –autonomous Multiagent systems may be –open –decomposed in local organizational or social context –promote indirect interactions via the environment However, for most of agent researchers –if agents are not intelligent and do not “speak” they are not agents –other communities fail in recognizing the contributions of agent-based computing –The agent community as a rather closed system…

17. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution17 Changing our Attitudes Till now, software have been modeled by adopting a mechanical attitude: –components and applications as mechanisms obeying mechanical laws and working accordingly in a predictable and provable way and engineered with a design attitude –My system behaves as desired because I have designed it to work that way In a dynamic world with multitudes of autonomous, possibly mobile, components, immersed in an environment end interaction with each other..this attitude cannot be maintained!

18. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution18 Impact on Computer Science Logic and mechanics can no longer be the only background Impossible to track and model the behaviour of many autonomous components –require macro-level modeling of software systems –chemistry, thermodynamics, macroecology Modelling openness and interactions with a dynamic environment –small perturbations can produce unpredictable global effects –biology, sociology, chaos theory Local interactions does not solve the problem –global behaviour can emerge from local interactions and be even more unpredictable –biology, theory of dissipative systems, the edge of chaos

19. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution19 Signals of the New Trend Unpredictable behaviors are already here –In the Internet (Crovella ’97) and in the WWW (Barabasi ’99) –In P2P Systems (Foster ’02) Other potential sources of impredictability have been observed –Role of environmental dynamics (Zambonelli & Roli ’02) Requires modeling software abstracting from the behavior of single components –Focusing on the systems as a whole –e.g., the entropy of software (Bruekner & Parunak 01) Other promising approaches can be identified –Organizational (Jennings, Sierra, etc.) and social (Tennenholtz, Davidsson, etc.) –But current researches in these topics often miss the “systems as a whole” perspective

20. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution20 Impact in Software Engineering Impossible to obtain well-defined programmed behaviors by design –too many components –too dynamic –need to achieve results via indirect programming How do very complex systems organize themselves? –organizational and social science –biology and ecology –modern thermodynamics Impossible to test and maintain software in a traditional way –simulation, test of the effect of the environment –error-free software a non-sense

21. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution21 Signals of this Trend Several approaches to indirect engineering… Physically inspired solutions –diffusive load balancing (Cybenko 89) –Field-based coordination (Mamei, 02) –Dynamical systems and attractors (Parunak 99) Biologically inspired solution –ant-based colonies (Dorigo, Parunak, 97) –Artificial immune systems Cellular approaches –evolved cellular automata (Sipper 00) –exploiting environmental dynamics (Zambonelli & Roli 02) From design to intention –systems behave like that because they have a goal to achieve –teleology rather then mechanics

22. Agent Group Università di Modena e Reggio Emilia ESAW 2002Signs of a Revolution22 Conclusions New characteristics of today’s computing systems and software systems Dramatic impact on CS and SE practices A Revolution (according to Kuhn meaning) –change of attitude: from mechanical systems to biological and physical ones from design to intention –new scientific background modern thermodynamics, non-linear systems, social sciences, macroecology, proteomics, theory of granunar media, Wolfram’s NKS, etc….. Can the multiagent community drive this revolution?