Electronic Newsletter Actions and Change

Electronic Newsletter on
Reasoning about Actions and Change


Issue 97037 Editor: Erik Sandewall 31.12.1997

The ETAI is organized and published under the auspices of the
European Coordinating Committee for Artificial Intelligence (ECCAI).

Today

The last Newsletter of this year contains a summary of the present status of the four articles and one research note that are presently under review in the ETAI area "Reasoning about Actions and Change". These have not been our only activities during the past months: we have had two panel discussions, one invited discussion (about Wolfgang Bibel's IJCAI paper), and several kinds of information has been transmitted through the present Newsletter. However, the status summary will serve both as a reminder that review of articles is our "core business", and as an encouragement for all to continue the discussion during the coming year.

At the end of the year it is appropriate to look back and to summarize. The present issue therefore also contains an editorial remark about the experience and the conclusions from the first year of ETAI and ENRAC activities.

At this point, I want to thank the Newsletter's contributors and readers for their participation in this enterprise since its start, and to send the best wishes for the new year. It has been a true pleasure to work with you, and I look forward to even more (inter)action and change during the coming year.


Received articles

Articles presently under review

Michael Thielscher

A Theory of Dynamic Diagnosis.

[summary]
[interactions]

Abstract: Diagnosis is, in general, more than a mere passive reasoning task. It often requires to actively produce observations by performing a test series on a faulty system. We present a theory of diagnosis which captures this dynamic aspect by appealing to Action Theory. The reactions of a system under healthy condition are modeled as indirect effects, so-called ramifications, of actions performed by the diagnostician. Under abnormal circumstances - i.e., if certain aspects or components of the system are faulty-one or more of these ramifications fail to materialize. Ramifications admitting exceptions is shown to giving rise to a hitherto unnoticed challenge - a challenge much like the one raised by the famous Yale Shooting counter-example in the context of the Frame Problem. Meeting this challenge is inevitable when searching for "good" diagnoses. As a solution, we adapt from a recent causality-based solution to the Qualification Problem the key principle of initial minimization. In this way, when suggesting a diagnosis our theory of dynamic diagnosis exploits causal information, in addition to possibly available, qualitative knowledge of the a priori likelihood of components to fail.

Some of the results in this paper have been preliminarily reported in (Thielscher, 1997a).

Received 7.10.1997. Status: Two recent question-contributions, awaiting answer.

Antonis Kakas and Rob Miller

Reasoning about Actions, Narratives and Ramification.

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Abstract: The Language E is a simple declarative language for describing the effects of action occurrences within a given narrative, using an ontology of actions, time points and fluents (i.e. properties which can change their truth values over time). This paper shows how E may be extended to deal with ramifications. More precisely, we show how Language E domain descriptions can include statements describing permanent relationships or constraints between fluents, and how the model theoretic semantics of E can be extended in an intuitive way to ensure that the effects of actions are appropriately propagated via such statements, whilst retaining E's simple approach to the frame problem. We also show how Event Calculus style logic programs may be used to compute consequences of such domain descriptions using standard SLDNF, even when only incomplete information is given about some initial state of affairs. Because of E's generality, these techniques are easily adaptable to other formalisms for reasoning about actions, such as the Language A and the Situation Calculus.

Various Prolog program listings associated with this paper are also available from http://www.dcs.qmw.ac.uk/~rsm/abstract15.html

Received 16.10.1997. Status: The article has given rise to extensive discussion.

Paolo Liberatore

Compilability of Domain Descriptions in the Language A.

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Research note, received 31.10.1997. Status: No discussion so far.

José Júlio Alferes, João A. Leite, Luís Moniz Pereira, Halina Przymusinska, and Teodor Przymusinski

Dynamic Logic Programming.

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Received 12.12.1997. Status: One question has been posed, not answered at this point.

Erik Sandewall

Logic-Based Modelling of Goal-Directed Behavior.

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Received 19.12.1997. Status: No discussion so far.


The Past Year

The development of the Electronic Transactions on Artificial Intelligence turns out to be an exploratory activity, even more than what we had anticipated when it started. The original idea was to create a new publication medium for scientific articles which would make the best use of the Internet availability. We foresaw a number of changes to the conventional practices that have been developed for paper-based journals, and in particular, we emphasized the importance of separating publishing (in the sense of "making public" and "making available") from the scientific quality control, that is, from the reviewing and refereering process. We also emphasized the importance of opening one part of the reviewing process, so that the traditional, confidential peer review would be replaced by a combination: an open discussion part where reviewers appear without the shroud of anonymity, and after it a rapid pass/fail decision by anonymous referees.

Finally, and maybe the most important of all, we emphasized the importance of having a publication medium where the authors retain the copyright of their articles, unlike what is the case in conventional journal publishing. The insight that this is a very important question has spread rapidly in our community during the past year.

These concepts were presented in the spring of 1997, and the ETAI was formally announced in May. In comparison with what we expected, there has been a small minus and a big plus. The minus is that the start was slower that we had thought: it took a while before papers started coming. However, I believe that the number of contributions will increase when the paper version of the ETAI begins to spread. The ETAI is "electronic" in the sense that it is stored and transmitted electronically, but noone expects you to read long, technical papers directly from the screen, and the paper printouts of the ETAI issues do look like any other journal. Professional-looking issues containing professional-quality articles will be our best advertisement.

The plus is that a whole new layer of communication concepts have evolved during the second half of 1997. Three layers can be identified here:

It is my firm conviction that we are just at the beginning of a very important development. Certainly we will see a lot more of it during the coming year. The future is bright!