In this paper, we study issues on disjunctions of propositional Horn theories. In particular, we consider deciding whether a disjunction of Horn theories is Horn, and, if not, computing a Horn core (i.e., a maximal Horn theory included in this disjunction) and Horn envelope (i.e., the minimum Horn theory including the disjunction). The problems are investigated for different representations of ...

The desirability of Horn clauses in logical deductive systems has long been recognized. The reasons are at least threefold. Firstly, while inference algorithms for full logics of any reasonable extent are typically intractable, for systems restricted to Horn clauses the picture is much better. (For example, in ordinary propositional logic, while the full satissability problem is NP-complete, a ...

We investigate reasoning and query answering in expressive domain knowledge bases (KBs) that are in OWL 2 Full and contain large individual data sets. For this, we introduce Hi(Horn-SROIQ) and meta-queries based on HiLog semantics. Hi(Horn-SROIQ) is extended from Horn-SROIQ, the horn fragment of the most expressive description logic (DL) for OWL 2 with well known low data complexity, by allowin...

We address the problem of finding a "tight" representation of Horn cardinality rules in a mixed integer programming model by describing a convex hull of it. A cardinality Horn rule asserts that if at least k of the propositions A\,..., Am are true, then B is true. We also show that Horn cardinality rules have properties analogous to ordinary Horn rules. 1 I n t r o d u c t i o n As rule-based s...

BACKGROUND Since the in vivo morphometric data on the menisci of the knee joint of Indian subjects are scarce, we hereby studied the width and thickness of the menisci using Magnetic Resonance Imaging (MRI) to establish standard dimensions of the normal medial and lateral meniscus as an aid to orthopaedic surgery. METHODS Eighty menisci from 40 knee joints were analysed in each of three regio...

Standard belief change assumes an underlying logic containing full classical propositional logic. However, there are good reasons for considering belief change in less expressive logics as well. In this paper we build on recent investigations by Delgrande on contraction for Horn logic. We show that the standard basic form of contraction, partial meet, is too strong in the Horn case. This result...

We are developing a new method using ultrasonic longitudinal and torsional vibration of a hollow-type stepped horn for hole machining. We foresee that the equipment can be simplified and miniaturized. In this paper, ultrasonic vibration sources of a hollow-type stepped horn without a diagonal slits vibration converter and with a diagonal slits vibration converter are used. The longitudinal and ...

Abstract Metastatic bone tumor-induced changes in gene transcription and translation in pain-related regions of the nervous system may participate in the development and maintenance of bone cancer pain. Epigenetic modifications including DNA methylation regulate gene transcription. Here, we report that intrathecal injection of decitabine, a DNA methyltransferase (DNMT) inhibitor, dose dependent...

One of the main characteristics of central sensitization associated with postinjury pain and chronic pain is increased excitability of the dorsal horn neurons in the spinal cord. Two electrophysiological features associated with the origin and modulation of central sensitization are wind-up of action potential frequency and long-term potentiation (LTP), which have been demonstrated previously i...