Elisa Marengo

Behavior-Oriented Commitment-based Protocols

Ever since the seminal work of Searle, two components of interaction protocols have been identified: constitutive rules, defining the meaning of actions and regulative rules, defining the flow of execution, i.e. the behavior the agent should show. The two parts together define the meaning of the interaction. Commitment-based protocols, however, usually do not account for the latter and, when they do it, they do not adopt a decoupled representation of the two parts. A clear distinction in the two representations would, however, bring many advantages, mainly residing in a greater openess of multi-agent systems, an easier re-use of protocols and of action definitions, and a finer specification of protocol properties. In this work we introduce the notion of behavior-oriented commitment-based protocols, which account both for the constitutive and the regulative specifications and that explicitly foresee a representation of the latter based on constraints among commitments. A language, named 2CL, for writing regulative specifications is also given.

Constitutive and regulative specifications of commitment protocols: A decoupled approach

Interaction protocols play a fundamental role in multiagent systems. In this work, after analyzing the trends that are emerging not only from research on multiagent interaction protocols but also from neighboring fields, like research on workflows and business processes, we propose a novel definition of commitment-based interaction protocols, that is characterized by the decoupling of the constitutive and the regulative specifications and that explicitly foresees a representation of the latter based on constraints among commitments. A clear distinction between the two representations has many advantages, mainly residing in a greater openness of multiagent systems, and an easier reuse of protocols and of action definitions. A language, named 2CL, for writing regulative specifications is also given together with a designer-oriented graphical notation.

Commitment-based protocols with behavioral rules and correctness properties of MAS

Commitment-based interaction protocols are a flexible way of representing the interaction of a set of agents, that is well-known and widely accepted by the research community. Normally these protocols consist of sets of actions with a shared meaning. From the point of view of an agent, however, the meaning of an action is completed by the context in which it is used: the context shapes the behavior of the agent in that the agent decides which actions to take depending on it. Indeed, since the seminal work of Searle (supported by other authors), two components of interaction protocols have been identified, constitutive rules and regulative rules, which altogether define the meaning of the interaction. Commitment-based protocols usually do not account for the latter. In this work we introduce a representation that explicitly includes regulative rules as constraints on commitments and, in the light of the work by Singh and Chopra [38], report the first steps in the analysis of the advantages brought by such introduction.

Reasoning-based curriculum sequencing and validation: integration in a service-oriented architecture

We present a service-oriented personalization system, set in an educational framework, based on a semantic annotation of courses including prerequisites and learning objectives. The system supports users in planning personalized curricula and in verifying the compliance of curricula against a model describing the designer goals. We have developed a prototype of the planning and validation services, by using SWI-Prolog and the SPIN model checker as reasoning engines. The services are supplied and combined in the Personal Reader framework.

Constraint Modeling for Curriculum Planning and Validation.

Curricula authoring is a complex process, involving different actors and different kinds of knowledge. Learners aim at acquiring expertise about some topic of their own interest, and need to perceive that the curriculum they attend will lead them toward their goal; when this does not happen, they become demotivated. Learners are all different, not only in their aims but also in their background knowledge and skills; curricula must carefully be tailored to the learners individual traits: when this does not happen, curricula are not effective from a pedagogical perspective. On the other hand, it is not possible to leave learners alone in the design of a curriculum because this activity involves both knowledge about thetopics to teach, and knowledge about teaching itself. It is one of the tasks of the school to support curricula authoring so as to guarantee the correctness of the result w.r.t. the teaching goals and to pedagogical strategies. In this article, we face the problem of authoring personalized curricula and propose a modular, layered architecture that accounts for the representation of learning resources, of the domain model, of the learner, and of pedagogical constraints, with the aim of supporting different validation tasks. The representation combines a Semantic Web approach to annotation with a declarative representation in linear temporal logic. The validation layer of the proposed architecture includes different kinds of inter-conceptual, post-construction verifications, all of which can be realized by means of model checking techniques. The article also reports about a prototype implementation based on the Personal Reader for education, a framework that supplies to its users personalization functionalities implemented in a service-oriented fashion.

Engineering commitment-based business protocols with the 2CL methodology

Enterprises must respect a number of regulations, with multilevel nature and which change along time. They must not only adapt their business interactions to the regulations and their changes but also evaluate the risks of violation of the new rules and to account for responsibilities. This work proposes a methodological framework for modeling and engineering business protocols, which gives primary position to the notions of commitment and responsibility, and supports the analysis of risks of violation when a new regulation is issued. We build on 2CL commitment-based protocols and introduce 2CL Methodology, a software engineering methodology for such protocols, which includes guidelines for specifying 2CL business protocols, for specialising them, and for composing a new 2CL protocol based on a set of given 2CL protocols. We developed a set of integrated software tools for the design and the analysis of 2CL protocols, with the aim of concretely supporting, on the one hand, designers in the task of identifying exposure to risks of violation, and, on the other hand, the management in the task of reasoning about accountability and of decision making. The proposal is evaluated by using a real-world case study from the banking sector.

A Generalized Commitment Machine for 2CL Protocols and Its Implementation

This work proposes an operational semantics for the commitment protocol language 2CL. This semantics relies on an extension of Singh’s Generalized Commitment Machine, that we named 2CL-Generalized Commitment Machines. The 2CL-Generalized Commitment Machine was implemented in Prolog by extending Winikoff, Liu and Harland’s implementation. The implementation is equipped with a graphical tool that allows the analyst to explore all the possible executions, showing both commitment and constraint violations, and thus helping the analyst as well as the protocol designer to identify the risks the interaction could encounter. The implementation is part of an Eclipse plug-in which supports 2CL-protocol design and analysis.

An Interaction-Oriented Agent Framework for Open Environments

The aim of the work is to develop formal models of interaction and of the related support infrastructures, that overcome the limits of the current approaches. We propose to represent explicitly not only the agents but also the computational environment in terms of rules, conventions, resources, tools, and services, that are functional to the coordination and cooperation of the agents. These models will enable the verification of the interaction in the MAS, thanks to the introduction of a novel social semantics of interaction based on commitments and on an explicit account of the regulative rules.

Supporting the Analysis of Risks of Violation in Business Protocols: The MiFID Case Study

Enterprises and especially banks are subject to a number of regulations, with multilevel nature which continuously change. They must not only to adapt their business processes to the regulations and their changes but also to evaluate the risks of violation of the new rules and to account for responsibilities. This work proposes a formal framework for modeling business interactions ruled by protocols that, being based on the notions of commitment and responsibility, supports the analysis of risks of violation when a new regulation is issued. We provide a software tool for the visualization of the “risk space” and apply the approach to a real-world case study in the banking sector.

Back to the future: An interaction-oriented framework for social computing

We propose an interaction-oriented framework and the related support infrastructure, that reifies commitment-based interaction protocols into programmable environments and artifacts. The use of commitments gives a normative characterization to coordination artifacts, while the use of artifacts enables the application of software engineering methodologies to protocols.