208 research outputs found
Intelligent GIS: Automatic generation of qualitative spatial information
This paper reports on an extension to Geographic Information Systems (GIS) that can intelligently analyse and record qualitative information of the surrounding area when adding a feature to a map. This recorded qualitative spatial information can be utilised to perform queries such as path generation using landmarks. Although, there is a lot of research on qualitative spatial reasoning, none of the currently available GIS do actually incorporate this kind of functionality. There have been systems developed that do have functions for adding new features, or generating paths; however they do not generally analyse and record, or use, qualitative information. We have implemented a prototype illustrating our approach. © Springer-Verlag Berlin Heidelberg 2006
Extension of RCC*-9 to Complex and Three-Dimensional Features and Its Reasoning System
RCC*-9 is a mereotopological qualitative spatial calculus for simple lines and regions. RCC*-9 can be easily expressed in other existing models for topological relations and thus can be viewed as a candidate for being a “bridge” model among various approaches. In this paper, we present a revised and extended version of RCC*-9, which can handle non-simple geometric features, such as multipolygons, multipolylines, and multipoints, and 3D features, such as polyhedrons and lower-dimensional features embedded in ℝ3. We also run experiments to compute RCC*-9 relations among very large random datasets of spatial features to demonstrate the JEPD properties of the calculus and also to compute the composition tables for spatial reasoning with the calculus
Electrical transport properties of manganite powders under pressure
We have measured the electrical resistance of micrometric to nanometric
powders of the LaPrCaMnO (LPCMO with y=0.3) manganite
for hydrostatic pressures up to 4 kbar. By applying different final thermal
treatments to samples synthesized by a microwave assisted denitration process,
we obtained two particular grain characteristic dimensions (40 nm and 1000 nm)
which allowed us to analyze the grain size sensitivity of the electrical
conduction properties of both the metal electrode interface with manganite (Pt
/ LPCMO) as well as the intrinsic intergranular interfaces formed by the LPCMO
powder, conglomerate under the only effect of external pressure. We also
analyzed the effects of pressure on the phase diagram of these powders. Our
results indicate that different magnetic phases coexist at low temperatures and
that the electrical transport properties are related to the intrinsic
interfaces, as we observe evidences of a granular behavior and an electronic
transport dominated by the Space Charge limited Current mechanism.Comment: 4 pages, 7 figures, to be published in Physica B Corresponding
author: C. Acha ([email protected]
Understanding the Spatial Complexity in Landscape Narratives Through Qualitative Representation of Space
Narratives are the richest source of information about the human experience of place. They represent events and movement, both physical and conceptual, within time and space. Existing techniques in geographical text analysis usually incorporate named places with coordinate information. This is a serious limitation because many textual references to geography are ambiguous, non-specific, or relative. It is imperative but hard for a geographic information system to capture a text’s sense of place, an imprecise concept. This work aims to utilize qualitative spatial representation and natural language processing to allow representations of all three characteristics of place (location, locale, sense of place) as found in textual sources
On Reasoning on Time and Location on the Web
Reasoning on time and location is receiving increasing attention on the Web due to emerging fields like Web adaptation, mobile computing, and the Semantic Web. Web applications in these fields often refer to rather complex temporal, calendric, and location information. Unfortunately, today’s Web languages and formalisms have merely primitive temporal and location data types and temporal and location reasoning capabilities – if any. This article reports on work in progress aiming at integrating temporal and locational reasoning into XML query and transformation operations. We analyze the problem and propose a concrete architecture. A prototype of the temporal reasoner, the WebCal system has already been realized
Visual Ontology Cleaning: Cognitive Principles and Applicability
In this paper we connect two research areas, the Qualitative
Spatial Reasoning and visual reasoning on ontologies. We discuss the logical
limitations of the mereotopological approach to the visual ontology
cleaning, from the point of view of its formal support. The analysis is
based on three different spatial interpretations wich are based in turn on
three different spatial interpretations of the concepts of an ontology.Ministerio de Educación y Ciencia TIN2004-0388
The arctic curve of the domain-wall six-vertex model
The problem of the form of the `arctic' curve of the six-vertex model with
domain wall boundary conditions in its disordered regime is addressed. It is
well-known that in the scaling limit the model exhibits phase-separation, with
regions of order and disorder sharply separated by a smooth curve, called the
arctic curve. To find this curve, we study a multiple integral representation
for the emptiness formation probability, a correlation function devised to
detect spatial transition from order to disorder. We conjecture that the arctic
curve, for arbitrary choice of the vertex weights, can be characterized by the
condition of condensation of almost all roots of the corresponding saddle-point
equations at the same, known, value. In explicit calculations we restrict to
the disordered regime for which we have been able to compute the scaling limit
of certain generating function entering the saddle-point equations. The arctic
curve is obtained in parametric form and appears to be a non-algebraic curve in
general; it turns into an algebraic one in the so-called root-of-unity cases.
The arctic curve is also discussed in application to the limit shape of
-enumerated (with ) large alternating sign matrices. In
particular, as the limit shape tends to a nontrivial limiting curve,
given by a relatively simple equation.Comment: 39 pages, 2 figures; minor correction
Exact solution of the six-vertex model with domain wall boundary condition. Critical line between ferroelectric and disordered phases
This is a continuation of the papers [4] of Bleher and Fokin and [5] of
Bleher and Liechty, in which the large asymptotics is obtained for the
partition function of the six-vertex model with domain wall boundary
conditions in the disordered and ferroelectric phases, respectively. In the
present paper we obtain the large asymptotics of on the critical line
between these two phases.Comment: 22 pages, 6 figures, to appear in the Journal of Statistical Physic
Gauged Inflation
We propose a model for cosmic inflation which is based on an effective
description of strongly interacting, nonsupersymmetric matter within the
framework of dynamical Abelian projection and centerization. The underlying
gauge symmetry is assumed to be with . Appealing to a
thermodynamical treatment, the ground-state structure of the model is
classically determined by a potential for the inflaton field (dynamical
monopole condensate) which allows for nontrivially BPS saturated and thereby
stable solutions. For this leads to decoupling of gravity from the
inflaton dynamics. The ground state dynamics implies a heat capacity for the
vacuum leading to inflation for temperatures comparable to the mass scale
of the potential. The dynamics has an attractor property. In contrast to the
usual slow-roll paradigm we have during inflation. As a consequence,
density perturbations generated from the inflaton are irrelevant for the
formation of large-scale structure, and the model has to be supplemented with
an inflaton independent mechanism for the generation of spatial curvature
perturbations. Within a small fraction of the Hubble time inflation is
terminated by a transition of the theory to its center symmetric phase. The
spontaneously broken symmetry stabilizes relic vector bosons in the
epochs following inflation. These heavy relics contribute to the cold dark
matter of the universe and potentially originate the UHECRs beyond the GZK
bound.Comment: 23 pages, 4 figures, subsection added, revision of text, to app. in
PR
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