Operational semantics of goal models in adaptive agents

ABSTRACT

Several agent-oriented software engineering methodologies address the emerging challenges posed by the increasing need of adaptive software. A common denominator of such methodologies is the paramount importance of the concept of goal model in order to understand the requirements of a software system. Goal models consist of goal graphs representing AND/OR-decomposition of abstract goals down to operationalisable leaf-level goals. Goal models are used primarily in the earlier phases of software engineering, for social modelling, requirements elicitation and analysis, to concretise abstract objectives, to detail them and to capture alternatives for their satisfaction.

Although various agent programming languages incorporate the notion of (leaf-level) goal as a language construct, none of them natively support the definition of goal models. However, the semantic gap between goal models used at design-time and the concept of goal used at implementation and execution time represent a limitation especially in the development of self-adaptive and fault-tolerant systems. In such systems, design-time knowledge on goals and variability becomes relevant at run-time, to take autonomous decisions for achieving high level objectives correctly.

Recently, unifying operational semantics for (leaf) goals have been proposed [15]. We extend this work to define an operational semantics for the behaviour of goals in goal models, maintaining the flexibility of using different goal types and conditions. We use a simple example to illustrate how the proposed approach effectively deals with the semantic gap between design-time goal models and run-time agent implementations.

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INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
        I.2.11 Distributed Artificial Intelligence
            Subjects: Intelligent agents

Additional Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.1 Requirements/Specifications
  D.3 PROGRAMMING LANGUAGES
      D.3.1 Formal Definitions and Theory

  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
        I.2.11 Distributed Artificial Intelligence
            Subjects: Languages and structures

General Terms:
Design, Languages, Theory

Keywords:
agent programming, formal semantics, goal models, goals