462 research outputs found
Specifying Logic Programs in Controlled Natural Language
Writing specifications for computer programs is not easy since one has to
take into account the disparate conceptual worlds of the application domain and
of software development. To bridge this conceptual gap we propose controlled
natural language as a declarative and application-specific specification
language. Controlled natural language is a subset of natural language that can
be accurately and efficiently processed by a computer, but is expressive enough
to allow natural usage by non-specialists. Specifications in controlled natural
language are automatically translated into Prolog clauses, hence become formal
and executable. The translation uses a definite clause grammar (DCG) enhanced
by feature structures. Inter-text references of the specification, e.g.
anaphora, are resolved with the help of discourse representation theory (DRT).
The generated Prolog clauses are added to a knowledge base. We have implemented
a prototypical specification system that successfully processes the
specification of a simple automated teller machine.Comment: 16 pages, compressed, uuencoded Postscript, published in Proceedings
CLNLP 95, COMPULOGNET/ELSNET/EAGLES Workshop on Computational Logic for
Natural Language Processing, Edinburgh, April 3-5, 199
Attempto - From Specifications in Controlled Natural Language towards Executable Specifications
Deriving formal specifications from informal requirements is difficult since
one has to take into account the disparate conceptual worlds of the application
domain and of software development. To bridge the conceptual gap we propose
controlled natural language as a textual view on formal specifications in
logic. The specification language Attempto Controlled English (ACE) is a subset
of natural language that can be accurately and efficiently processed by a
computer, but is expressive enough to allow natural usage. The Attempto system
translates specifications in ACE into discourse representation structures and
into Prolog. The resulting knowledge base can be queried in ACE for
verification, and it can be executed for simulation, prototyping and validation
of the specification.Comment: 15 pages, compressed, uuencoded Postscript, to be presented at EMISA
Workshop 'Naturlichsprachlicher Entwurf von Informationssystemen -
Grundlagen, Methoden, Werkzeuge, Anwendungen', May 28-30, 1996, Ev. Akademie
Tutzin
Attempto Controlled English (ACE)
Attempto Controlled English (ACE) allows domain specialists to interactively
formulate requirements specifications in domain concepts. ACE can be accurately
and efficiently processed by a computer, but is expressive enough to allow
natural usage. The Attempto system translates specification texts in ACE into
discourse representation structures and optionally into Prolog. Translated
specification texts are incrementally added to a knowledge base. This knowledge
base can be queried in ACE for verification, and it can be executed for
simulation, prototyping and validation of the specification.Comment: 13 pages, compressed, uuencoded Postscript, to be presented at CLAW
96, The First International Workshop on Controlled Language Applications,
Katholieke Universiteit Leuven, 26-27 March 199
Arithmetic of Calabi-Yau Varieties and Rational Conformal Field Theory
It is proposed that certain techniques from arithmetic algebraic geometry
provide a framework which is useful to formulate a direct and intrinsic link
between the geometry of Calabi-Yau manifolds and the underlying conformal field
theory. Specifically it is pointed out how the algebraic number field
determined by the fusion rules of the conformal field theory can be derived
from the number theoretic structure of the cohomological Hasse-Weil L-function
determined by Artin's congruent zeta function of the algebraic variety. In this
context a natural number theoretic characterization arises for the quantum
dimensions in this geometrically determined algebraic number field.Comment: 21 pages, Late
Landau-Ginzburg String Vacua
We investigate a class of (2,2) supersymmetric string vacua which may be
represented as Landau--Ginzburg theories with a quasihomogeneous potential
which has an isolated singularity at the origin. There are at least three
thousand distinct models in this class. All vacua of this type lead to Euler
numbers which lie in the range . The Euler
characteristics do not pair up completely hence the space of Landau--Ginzburg
ground states is not mirror symmetric even though it exhibits a high degree of
symmetry. We discuss in some detail the relation between Landau--Ginzburg
models and Calabi--Yau manifolds and describe a subtlety regarding
Landau--Ginzburg potentials with an arbitrary number of fields. We also show
that the use of topological identities makes it possible to relate
Landau-Ginzburg theories to types of Calabi-Yau manifolds for which the usual
Landau-Ginzburg framework does not apply.Comment: 92p
Sound Localization in Single-Sided Deaf Participants Provided With a Cochlear Implant
Spatial hearing is crucial in real life but deteriorates in participants with severe sensorineural hearing loss or single-sided deafness. This ability can potentially be improved with a unilateral cochlear implant (CI). The present study investigated measures of sound localization in participants with single-sided deafness provided with a CI. Sound localization was measured separately at eight loudspeaker positions (4°, 30°, 60°, and 90°) on the CI side and on the normal-hearing side. Low- and high-frequency noise bursts were used in the tests to investigate possible differences in the processing of interaural time and level differences. Data were compared to normal-hearing adults aged between 20 and 83. In addition, the benefit of the CI in speech understanding in noise was compared to the localization ability. Fifteen out of 18 participants were able to localize signals on the CI side and on the normal-hearing side, although performance was highly variable across participants. Three participants always pointed to the normal-hearing side, irrespective of the location of the signal. The comparison with control data showed that participants had particular difficulties localizing sounds at frontal locations and on the CI side. In contrast to most previous results, participants were able to localize low-frequency signals, although they localized high-frequency signals more accurately. Speech understanding in noise was better with the CI compared to testing without CI, but only at a position where the CI also improved sound localization. Our data suggest that a CI can, to a large extent, restore localization in participants with single-sided deafness. Difficulties may remain at frontal locations and on the CI side. However, speech understanding in noise improves when wearing the CI. The treatment with a CI in these participants might provide real-world benefits, such as improved orientation in traffic and speech understanding in difficult listening situations
Heterotic Gauge Structure of Type II K3 Fibrations
We show that certain classes of K3 fibered Calabi-Yau manifolds derive from
orbifolds of global products of K3 surfaces and particular types of curves.
This observation explains why the gauge groups of the heterotic duals are
determined by the structure of a single K3 surface and provides the dual
heterotic picture of conifold transitions between K3 fibrations. Abstracting
our construction from the special case of K3 hypersurfaces to general K3
manifolds with an appropriate automorphism, we show how to construct Calabi-Yau
threefold duals for heterotic theories with arbitrary gauge groups. This
generalization reveals that the previous limit on the Euler number of
Calabi-Yau manifolds is an artifact of the restriction to the framework of
hypersurfaces.Comment: 15 pages, 3 eps figure
Strange semimetal dynamics in SrIrO
The interplay of electronic correlations, multi-orbital excitations, and
strong spin-orbit coupling is a fertile ground for new states of matter in
quantum materials. Here, we report on a confocal Raman scattering study of
momentum-resolved charge dynamics from a thin film of semimetallic perovskite
. We demonstrate that the charge dynamics, characterized by a
broad continuum, is well described in terms of the marginal Fermi liquid
phenomenology. In addition, over a wide temperature regime, the inverse
scattering time is for all momenta close to the Planckian limit
. Thus, is a
semimetallic multi-band system that is as correlated as, for example, the
cuprate superconductors. The usual challenge to resolve the charge dynamics in
multi-band systems with very different mobilities is circumvented by taking
advantage of the momentum space selectivity of polarized electronic Raman
scattering. The Raman responses of both hole- and electron-pockets display an
electronic continuum extending far beyond 1000\icm (125 meV), much larger
than allowed by the phase space for creating particle-hole pairs in a regular
Fermi liquid. Analyzing this response in the framework of a memory function
formalism, we are able to extract the frequency dependent scattering rate and
mass enhancement factor of both types of charge carriers, which in turn allows
us to determine the carrier-dependent mobilities and electrical resistivities.
The results are well consistent with transport measurement and demonstrate the
potential of this approach to investigate the charge dynamics in multi-band
systems
Universality of optimal measurements
We present optimal and minimal measurements on identical copies of an unknown
state of a qubit when the quality of measuring strategies is quantified with
the gain of information (Kullback of probability distributions). We also show
that the maximal gain of information occurs, among isotropic priors, when the
state is known to be pure. Universality of optimal measurements follows from
our results: using the fidelity or the gain of information, two different
figures of merits, leads to exactly the same conclusions. We finally
investigate the optimal capacity of copies of an unknown state as a quantum
channel of information.Comment: Revtex, 5 pages, no figure
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