17, Information-seeking agent dialogs with permissions and arguments

Notes taken from ‘Information-seeking agent dialogs with permissions and arguments’ (2006), by Sylvie Doutre et al.

“… Many distributed information systems require agents to have appropriate authorisation to obtain access to information… We present a denotational semantics for such dialogs, drawing on Tuple Centres (programmable Tuple Spaces)…”

1, Introduction

… we present a formal syntax and semantics for such information-seeking dialogs involving permissions and arguments…

2.1, Dialog systems

The common elements of dialog systems are…

A typology of human dialogs was articulated by Walton and Krabbe, based upon the overall goal of the dialogue, the participants’ individual dialog goals, and the information they have at the commencement of the dialog (the topic language and the context)…

2.2, Tuple spaces

… a model of communication between distributed computational entities… The essential idea is that computational agents connected together may create named object stores, called tuples, which persist, even beyond the lifetimes of their creators, until explicitly deleted… They are stored in tuple spaces, which are black-board-like shared data stores, and are normally accessed by other agents by associative pattern matching… There are three basic operators on tuple spaces: out, rd, in…

2.3, LGL as a semantics for dialog systems

… (We) show how Law-Governed Linda (LGL) can be used as a denotational semantics for these systems, by associating elements of an LGL 5-tuple to the elements of the dialog system. Note that the dialog goal and the outcome rules have no associated elements in LGL…

3, Secure info-seek dialogue

3.1, Motivating example…

3.2, Protocol syntax

… In this system, an argument must be provided by an agent to justify it having permission to access some information. If access to information for agent x is refused by agent y, then agent x must try to persuade agent y that it should be allowed permission. This persuasion is made using arguments. If agent y yields to agent x’s arguments, then y provides x the information requested.

(Definitions given for Participants, Dialog goal, Context, Topic language, Communication language, Protocol, Effect rules, Outcome rules)

3.3, LGL semantics

(Associations to elements of an LGL 5-tuple given for elements of the dialog system: Participants, Context, Communication language, Protocol, Effect rules)

3.4, Illustration…

4, Implementation

In Section 1, we stated that our primary objective was the development of a semantics for these Information-seeking dialogs which facilitated implementation of the protocol. In order to assess whether the protocol and semantics of Section 3 met this objective, we undertook an implementation…

5, Related work and conclusions

… Our contribution in this paper is a novel semantics for information-seeking agent communications protocols involving permissions and arguments, in which utterances under the protocol are translated into commands in Law-Governed Linda and, through them, into actions on certain associated tuple spaces…