5,046 research outputs found
Hypertableau Reasoning for Description Logics
We present a novel reasoning calculus for the description logic SHOIQ^+---a
knowledge representation formalism with applications in areas such as the
Semantic Web. Unnecessary nondeterminism and the construction of large models
are two primary sources of inefficiency in the tableau-based reasoning calculi
used in state-of-the-art reasoners. In order to reduce nondeterminism, we base
our calculus on hypertableau and hyperresolution calculi, which we extend with
a blocking condition to ensure termination. In order to reduce the size of the
constructed models, we introduce anywhere pairwise blocking. We also present an
improved nominal introduction rule that ensures termination in the presence of
nominals, inverse roles, and number restrictions---a combination of DL
constructs that has proven notoriously difficult to handle. Our implementation
shows significant performance improvements over state-of-the-art reasoners on
several well-known ontologies
Tuplix Calculus
We introduce a calculus for tuplices, which are expressions that generalize
matrices and vectors. Tuplices have an underlying data type for quantities that
are taken from a zero-totalized field. We start with the core tuplix calculus
CTC for entries and tests, which are combined using conjunctive composition. We
define a standard model and prove that CTC is relatively complete with respect
to it. The core calculus is extended with operators for choice, information
hiding, scalar multiplication, clearing and encapsulation. We provide two
examples of applications; one on incremental financial budgeting, and one on
modular financial budget design.Comment: 22 page
Pollution perception: An inquiry into intergenerational equity
In this article we extend the recent literature on overlapping generations with a pollution sector by allowing generations to have a certain pollution perception with regards to the stock of pollution. Pollution perception, assumed to be part of the generations' preferences, can be either a concern for the flow of pollution only, or for the stock, or anything in between. We analyse the different steady states for their implications on intergenerational equity. Our main result is that if generations are only partly concerned with the actual stock of pollution, then periodic cycling will occur. We use the concept of Intergenerational Moral Intuition to analyse this periodic cycling. Our main policy conclusion is that decision makers who would like to achieve intergenerational equitable outcomes must either use the maximin criterion or take decisions spanning several generations in order to avoid the period cycling effect.
Tractable approximate deduction for OWL
Acknowledgements This work has been partially supported by the European project Marrying Ontologies and Software Technologies (EU ICT2008-216691), the European project Knowledge Driven Data Exploitation (EU FP7/IAPP2011-286348), the UK EPSRC project WhatIf (EP/J014354/1). The authors thank Prof. Ian Horrocks and Dr. Giorgos Stoilos for their helpful discussion on role subsumptions. The authors thank Rafael S. Gonçalves et al. for providing their hotspots ontologies. The authors also thank BoC-group for providing their ADOxx Metamodelling ontologies.Peer reviewedPostprin
Propositional logic with short-circuit evaluation: a non-commutative and a commutative variant
Short-circuit evaluation denotes the semantics of propositional connectives
in which the second argument is evaluated only if the first argument does not
suffice to determine the value of the expression. Short-circuit evaluation is
widely used in programming, with sequential conjunction and disjunction as
primitive connectives.
We study the question which logical laws axiomatize short-circuit evaluation
under the following assumptions: compound statements are evaluated from left to
right, each atom (propositional variable) evaluates to either true or false,
and atomic evaluations can cause a side effect. The answer to this question
depends on the kind of atomic side effects that can occur and leads to
different "short-circuit logics". The basic case is FSCL (free short-circuit
logic), which characterizes the setting in which each atomic evaluation can
cause a side effect. We recall some main results and then relate FSCL to MSCL
(memorizing short-circuit logic), where in the evaluation of a compound
statement, the first evaluation result of each atom is memorized. MSCL can be
seen as a sequential variant of propositional logic: atomic evaluations cannot
cause a side effect and the sequential connectives are not commutative. Then we
relate MSCL to SSCL (static short-circuit logic), the variant of propositional
logic that prescribes short-circuit evaluation with commutative sequential
connectives.
We present evaluation trees as an intuitive semantics for short-circuit
evaluation, and simple equational axiomatizations for the short-circuit logics
mentioned that use negation and the sequential connectives only.Comment: 34 pages, 6 tables. Considerable parts of the text below stem from
arXiv:1206.1936, arXiv:1010.3674, and arXiv:1707.05718. Together with
arXiv:1707.05718, this paper subsumes most of arXiv:1010.367
Our Place in New Zealand Culture: How the Museum of New Zealand Constructs Biculturalism
The Museum of New Zealand Te Papa Tongarewa opened in 1998 amidst controversy but has been a huge popular success and has become an icon of national identity. The controversy was confined to elite circles and stemmed from criticisms of the contrasting ways in which Maori and Pakeha (European) cultural items were displayed — the former in a reverential manner and the latter as a kind of 'amusement arcade' of supposedly incoherent, temporary and mocking exhibits. Through an analysis of these displays and of the representations surrounding them, this paper argues that the sacred/profane dichotomy promulgated by the Museum may be open to argument but is probably an inescapable feature of the official policy of biculturalism in a postcolonial setting
Space-Time Intervals Underlie Human Conscious Experience, Gravity, and a Theory of Everything
Space-time intervals are the fundamental components of conscious experience, gravity, and a Theory of Everything. Space-time intervals are relationships that arise naturally between events. They have a general covariance (independence of coordinate systems, scale invariance), a physical constancy, that encompasses all frames of reference. There are three basic types of space-time intervals (light-like, time-like, space-like) which interact to create space-time and its properties. Human conscious experience is a four-dimensional space-time continuum created through the processing of space-time intervals by the brain; space-time intervals are the source of conscious experience (observed physical reality). Human conscious experience is modeled by Einstein’s special theory of relativity, a theory designed specifically from the general covariance of space-time intervals (for inertial frames of reference). General relativity is our most accurate description of gravity. In general relativity, the general covariance of space-time intervals is extended to all frames of reference (inertial and non-inertial), including gravitational reference frames; space-time intervals are the source of gravity in general relativity. The general covariance of space-time intervals is further extended to quantum mechanics; space-time intervals are the source of quantum gravity. The general covariance of space-time intervals seamlessly merges general relativity with quantum field theory (the two grand theories of the universe). Space-time intervals consequently are the basis of a Theory of Everything (a single all-encompassing coherent theoretical framework of physics that fully explains and links together all physical aspects of the universe). This theoretical framework encompasses our observed physical reality (conscious experience) as well; space-time intervals link observed physical reality to actual physical reality. This provides an accurate and reliable match between observed physical reality and the physical universe by which we can carry on our activity. The Minkowski metric, which defines generally covariant space-time intervals, may be considered an axiom (premise, postulate) for the Theory of Everything
The administrative window into the integrated DBMS
A good office automation system manned by a team of facilitators seeking opportunities to serve end users could go a long way toward defining a DBMS that serves management. The problems of DBMS organization, alternative approaches to solving some of the major problems, problems that may have no solution, and how office automation fits into the development of the manager's management information system are discussed
Deductive planning and plan reuse in a command language environment
In this paper we introduce a deductive planning system currently being developed as the kernel of an intelligent help system. It consists of a deductive planner and a plan reuse component and with that provides planning from first as well as planning from second principles. Both components rely upon an interval-based temporal logic. The deductive formalisms realizing plan formation from formal specifications and the reuse of already existing plans respectively are presented and demonstrated by examples taken from an operating system\u27s domain
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