In logic programming, a variable is said to be local if it occurs in a clause body but not in its head atom. It is well-known that local variables are the main cause of inefficiency (sometimes even incompleteness) in negative goal computation. The problem is twofold. First, the negation of a clause body that contains a local variables is not expressible without universal quantification, whereas...

A 27 year old male presented with downward displacement of the left globe and severe enophthalmous. He had a history blunt trauma to head during traffic-road accident previous weeks.

You are going to Paul’s party tonight. You have a long day of work ahead of you before that, but you can’t wait to get there. Your annoying friend comes up to you and says, ‘Hi! Oh, are you going to Paul’s party tonight? I don’t think I’ll go. Unless your going?’ You reply, ‘I have to work.’ There are lies and then there are misleading utterances that are not lies. You did not lie to your frien...

We define choice logic programs as negation-free datalog programs that allow rules to have exclusive-only disjunctions in the head. We show that choice programs are equivalent to semi-negative datalog programs, at least as far as stable models are concerned. We also discuss an application where strategic games can be naturally formulated as choice programs; it turns out that the stable models o...

In this paper we show that an arbitrary propositional theory, when interpreted under the answer sets semantics (called Equilibrium Logic for this general syntax), can always be reexpressed as a strongly equivalent disjunctive logic program, possibly with negation in the head. We provide two different proofs for this result: one involving a syntactic trasnformation, and one that constructs a pro...

This paper describes the design of AutoTutor, a fully automated computer tutor that simulates dialogue moves of normal human tutors and that will eventually incorporate sophisticated tutoring strategies. AutoTutor follows a curriculum script that presents subtopics in di erent forms, such as didactic content, graphic displays, questions, and problems. The tutor selects dialogue moves that assis...

Virtual reality user interfaces usually use a Head Mounted Display HMD for viewing a simulated vir tual world Typical HMD s are rigidly mounted on the user s head and supply a head relative xed view port to the virtual world The direction of view is supplied by a D position and orientation tracker such as a Polhemus Isotrak One characteristic of HMD use is that HMD s are heavy and require that ...

The aim of the study was to compare head posture in young, adult emmetropes and corrected myopes during a reading task. Thirty-two (32) myopes (mean spherical equivalent: -3.46±2.35 D) and 22 emmetropes (mean spherical equivalent: -0.03±0.36 D) participated in the study. Of the myopes, 16 were progressing (rate of progression ⩾-0.5D over the previous 2 years), 12 were stable (changes of -0.25 D...