48 research outputs found
Ordered Information Systems and Graph Granulation
The concept of an Information System, as used in Rough Set theory, is extended to the case of a partially ordered universe equipped with a set of order preserving attributes. These information systems give rise to partitions of the universe where the set of equivalence classes is partially ordered. Such ordered partitions correspond to relations on the universe which are reflexive and transitive. This correspondence allows the definition of approximation operators for an ordered information system by using the concepts of opening and closing from mathematical morphology. A special case of partial orders are graphs and hypergraphs and these provide motivation for the need to consider approximations on partial orders
Strong Completeness and the Finite Model Property for Bi-Intuitionistic Stable Tense Logics
Bi-Intuitionistic Stable Tense Logics (BIST Logics) are tense logics with a Kripke semantics where worlds in a frame are equipped with a pre-order as well as with an accessibility relation which is ‘stable’ with respect to this pre-order. BIST logics are extensions of a logic, BiSKt, which arose in the semantic context of hypergraphs, since a special case of the pre-order can represent the incidence structure of a hypergraph. In this paper we provide, for the first time, a Hilbert-style axiomatisation of BISKt and prove the strong completeness of BiSKt. We go on to prove strong completeness of a class of BIST logics obtained by extending BiSKt by formulas of a certain form. Moreover we show that the finite model property and the decidability hold for a class of BIST logics
The Logic of Discrete Qualitative Relations
We consider a modal logic based on mathematical morphology which allows the expression of mereotopological relations between subgraphs. A specific form of topological closure between graphs is expressible in this logic, both as a combination of the negation ¬ and its dual , and as modality, using the stable relation Q, which describes the incidence structure of the graph. This allows to define qualitative spatial relations between discrete regions, and to compare them with earlier works in mereotopology, both in the discrete and in the continuous space
The Logic of Discrete Qualitative Relations
We consider a modal logic based on mathematical morphology which allows the expression of mereotopological relations between subgraphs. A specific form of topological closure between graphs is expressible in this logic, both as a combination of the negation ¬ and its dual , and as modality, using the stable relation Q, which describes the incidence structure of the graph. This allows to define qualitative spatial relations between discrete regions, and to compare them with earlier works in mereotopology, both in the discrete and in the continuous space
A framework for utility data integration in the UK
In this paper we investigate various factors which prevent utility knowledge from being
fully exploited and suggest that integration techniques can be applied to improve the
quality of utility records. The paper suggests a framework which supports knowledge
and data integration. The framework supports utility integration at two levels: the
schema and data level. Schema level integration ensures that a single, integrated geospatial
data set is available for utility enquiries. Data level integration improves utility data
quality by reducing inconsistency, duplication and conflicts. Moreover, the framework
is designed to preserve autonomy and distribution of utility data. The ultimate aim of
the research is to produce an integrated representation of underground utility infrastructure
in order to gain more accurate knowledge of the buried services. It is hoped that
this approach will enable us to understand various problems associated with utility data,
and to suggest some potential techniques for resolving them
Symmetric Heyting relation algebras with applications to hypergraphs
A relation on a hypergraph is a binary relation on the set consisting of all the nodes and the edges, and which satisfies a constraint involving the incidence structure of the hypergraph. These relations correspond to join preserving mappings on the lattice of sub-hypergraphs. This paper introduces a generalization of a relation algebra in which the Boolean algebra part is replaced by a Heyting algebra that supports an order-reversing involution. A general construction for these symmetric Heyting relation algebras is given which includes as a special case the algebra of relations on a hypergraph. A particular feature of symmetric Heyting relation algebras is that instead of an involutory converse operation they possess both a left converse and a right converse which form an adjoint pair of operations. Properties of the converses are established and used to derive a generalization of the well-known connection between converse, complement, erosion and dilation in mathematical morphology. This provides part of the foundation necessary to develop mathematical morphology on hypergraphs based on relations on hypergraphs
Axiomatic and tableau-based reasoning for Kt(H,R)
We introduce a tense logic, called Kt(H, R), arising from logics for spatial reasoning. Kt(H, R) is a multi-modal logic with two modalities and their converses defined with respect to a pre-order and a relation stable over this pre-order. We show Kt(H,R) is decidable, it has the effective finite model property and reasoning in Kt(H,R) is PSPACE-complete. Two complete Hilbert-style axiomatisations are given. The main focus of the paper is tableau-based reasoning. Our aim is to gain insight into the numerous possibilities of defining tableau calculi and their properties. We present several labelled tableau calculi for Kt(H,R) in which the theory rules range from accommodating correspondence properties closely, to accommodating Hilbert axioms closely. The calculi provide the basis for decision procedures that have been imple- mented and tested on modal and intuitionistic problems
A Bi-Intuitionistic Modal Logic: Foundations and Automation
The paper introduces a bi-intuitionistic modal logic, called BISKT, with two adjoint pairs of tense operators. The semantics of BISKT is defined using Kripke models in which the set of worlds carries a pre-order relation as well as an accessibility relation, and the two relations are linked by a stability condition. A special case of these models arises from graphs in which the worlds are interpreted as nodes and edges of graphs, and formulae represent subgraphs. The pre-order is the incidence structure of the graphs. We present a comprehensive study of the logic, giving decidability, complexity and correspondence results. We also show the logic has the effective finite model property. We present a sound, complete and terminating tableau calculus for the logic and use the MetTeL system to explore implementations of different versions of the calculus. An experimental evaluation gave good results for satisfiable problems using predecessor blocking
Inconsistent boundaries
Research on this paper was supported by a grant from the Marsden Fund, Royal Society of New Zealand.Mereotopology is a theory of connected parts. The existence of boundaries, as parts of everyday objects, is basic to any such theory; but in classical mereotopology, there is a problem: if boundaries exist, then either distinct entities cannot be in contact, or else space is not topologically connected (Varzi in Noûs 31:26–58, 1997). In this paper we urge that this problem can be met with a paraconsistent mereotopology, and sketch the details of one such approach. The resulting theory focuses attention on the role of empty parts, in delivering a balanced and bounded metaphysics of naive space.PostprintPeer reviewe
Identification of cryptolepine metabolites in rat and human hepatocytes and metabolism and pharmacokinetics of cryptolepine in Sprague Dawley rats
YesBackground: This study aims at characterizing the in vitro metabolism of cryptolepine using human and rat
hepatocytes, identifying metabolites in rat plasma and urine after a single cryptolepine dose, and evaluating the
single-dose oral and intravenous pharmacokinetics of cryptolepine in male Sprague Dawley (SD) rats.
Methods: The in vitro metabolic profiles of cryptolepine were determined by LC-MS/MS following incubation with
rat and human hepatocytes. The in vivo metabolic profile of cryptolepine was determined in plasma and urine
samples from Sprague Dawley rats following single-dose oral administration of cryptolepine. Pharmacokinetic
parameters of cryptolepine were determined in plasma and urine from Sprague Dawley rats after single-dose
intravenous and oral administration.
Results: Nine metabolites were identified in human and rat hepatocytes, resulting from metabolic pathways
involving oxidation (M2-M9) and glucuronidation (M1, M2, M4, M8, M9). All human metabolites were found in rat
hepatocyte incubations except glucuronide M1. Several metabolites (M2, M6, M9) were also identified in the urine
and plasma of rats following oral administration of cryptolepine. Unchanged cryptolepine detected in urine was
negligible. The Pharmacokinetic profile of cryptolepine showed a very high plasma clearance and volume of
distribution (Vss) resulting in a moderate average plasma half-life of 4.5 h. Oral absorption was fast and plasma
exposure and oral bioavailability were low.
Conclusions: Cryptolepine metabolism is similar in rat and human in vitro with the exception of direct glucuronidation
in human. Clearance in rat and human is likely to include a significant metabolic contribution, with proposed primary
human metabolism pathways hydroxylation, dihydrodiol formation and glucuronidation. Cryptolepine showed extensive
distribution with a moderate half-life.Funded by Novartis Pharma under the Next Generation Scientist Program