2,032 research outputs found
Knowing Values and Public Inspection
We present a basic dynamic epistemic logic of "knowing the value". Analogous
to public announcement in standard DEL, we study "public inspection", a new
dynamic operator which updates the agents' knowledge about the values of
constants. We provide a sound and strongly complete axiomatization for the
single and multi-agent case, making use of the well-known Armstrong axioms for
dependencies in databases
Energy Distribution in disordered elastic Networks
Disordered networks are found in many natural and artificial materials, from gels or cytoskeletal structures to metallic foams or bones. Here, the energy distribution in this type of networks is modeled, taking into account the orientation of the struts. A correlation between the orientation and the energy per unit volume is found and described as a function of the connectivity in the network and the relative bending stiffness of the struts. If one or both parameters have relatively large values, the struts aligned in the loading direction present the highest values of energy. On the contrary, if these have relatively small values, the highest values of energy can be reached in the struts oriented transversally. This result allows explaining in a simple way remodeling processes in biological materials, for example, the remodeling of trabecular bone and the reorganization in the cytoskeleton. Additionally, the correlation between the orientation, the affinity, and the bending-stretching ratio in the network is discussed
Low-effort place recognition with WiFi fingerprints using deep learning
Using WiFi signals for indoor localization is the main localization modality
of the existing personal indoor localization systems operating on mobile
devices. WiFi fingerprinting is also used for mobile robots, as WiFi signals
are usually available indoors and can provide rough initial position estimate
or can be used together with other positioning systems. Currently, the best
solutions rely on filtering, manual data analysis, and time-consuming parameter
tuning to achieve reliable and accurate localization. In this work, we propose
to use deep neural networks to significantly lower the work-force burden of the
localization system design, while still achieving satisfactory results.
Assuming the state-of-the-art hierarchical approach, we employ the DNN system
for building/floor classification. We show that stacked autoencoders allow to
efficiently reduce the feature space in order to achieve robust and precise
classification. The proposed architecture is verified on the publicly available
UJIIndoorLoc dataset and the results are compared with other solutions
Endmember extraction algorithms from hyperspectral images
During the last years, several high-resolution sensors have been developed for hyperspectral remote sensing applications.
Some of these sensors are already available on space-borne devices. Space-borne sensors are currently
acquiring a continual stream of hyperspectral data, and new efficient unsupervised algorithms are required to
analyze the great amount of data produced by these instruments. The identification of image endmembers is a
crucial task in hyperspectral data exploitation. Once the individual endmembers have been identified, several
methods can be used to map their spatial distribution, associations and abundances. This paper reviews the Pixel
Purity Index (PPI), N-FINDR and Automatic Morphological Endmember Extraction (AMEE) algorithms developed
to accomplish the task of finding appropriate image endmembers by applying them to real hyperspectral
data. In order to compare the performance of these methods a metric based on the Root Mean Square Error
(RMSE) between the estimated and reference abundance maps is used
Some Remarks on the Model Theory of Epistemic Plausibility Models
Classical logics of knowledge and belief are usually interpreted on Kripke
models, for which a mathematically well-developed model theory is available.
However, such models are inadequate to capture dynamic phenomena. Therefore,
epistemic plausibility models have been introduced. Because these are much
richer structures than Kripke models, they do not straightforwardly inherit the
model-theoretical results of modal logic. Therefore, while epistemic
plausibility structures are well-suited for modeling purposes, an extensive
investigation of their model theory has been lacking so far. The aim of the
present paper is to fill exactly this gap, by initiating a systematic
exploration of the model theory of epistemic plausibility models. Like in
'ordinary' modal logic, the focus will be on the notion of bisimulation. We
define various notions of bisimulations (parametrized by a language L) and show
that L-bisimilarity implies L-equivalence. We prove a Hennesy-Milner type
result, and also two undefinability results. However, our main point is a
negative one, viz. that bisimulations cannot straightforwardly be generalized
to epistemic plausibility models if conditional belief is taken into account.
We present two ways of coping with this issue: (i) adding a modality to the
language, and (ii) putting extra constraints on the models. Finally, we make
some remarks about the interaction between bisimulation and dynamic model
changes.Comment: 19 pages, 3 figure
Ecografía del tracto gastrointestinal en pequeños animales
En el presente artículo se realiza una descripción de la imagen ecográfica normal del tracto digestivo en el perro y en el gato y de las diferentes patologías que pueden observarse
Geometric diagram for representing shape quality in mesh refinement
summary:We review and discuss a method to normalize triangles by the longest-edge. A geometric diagram is described as a helpful tool for studying and interpreting the quality of triangle shapes during iterative mesh refinements. Modern CAE systems as those implementing the finite element method (FEM) require such tools for guiding the user about the quality of generated triangulations. In this paper we show that a similar method and corresponding geometric diagram in the three-dimensional case do not exist
Magnetic Tension of Sunspot Fine Structures
The equilibrium structure of sunspots depends critically on its magnetic
topology and is dominated by magnetic forces. Tension force is one component of
the Lorentz force which balances the gradient of magnetic pressure in
force-free configurations. We employ the tension term of the Lorentz force to
clarify the structure of sunspot features like penumbral filaments, umbral
light bridges and outer penumbral fine structures. We compute vertical
component of tension term of Lorentz force over two active regions namely NOAA
AR 10933 and NOAA AR 10930 observed on 05 January 2007 and 12 December 2006
respectively. The former is a simple while latter is a complex active region
with highly sheared polarity inversion line (PIL). The vector magnetograms used
are obtained from Hinode(SOT/SP). We find an inhomogeneous distribution of
tension with both positive and negative signs in various features of the
sunspots. The existence of positive tension at locations of lower field
strength and higher inclination is compatible with the uncombed model of the
penumbral structure. Positive tension is also seen in umbral light bridges
which could be indication of uncombed structure of the light bridge. Likewise,
the upward directed tension associated with bipolar regions in the penumbra
could be a direct confirmation of the sea serpent model of penumbral
structures. Upward directed tension at the PIL of AR 10930 seems to be related
to flux emergence. The magnitude of the tension force is greater than the force
of gravity in some places, implying a nearly force-free configuration for these
sunspot features. From our study, magnetic tension emerges as a useful
diagnostic of the local equilibrium of the sunspot fine structures.Comment: 06 pages, 6 figures; Accepted for publication in the Astronomy &
Astrophysics as a "Letter to the Editor
Endmember extraction algorithms from hyperspectral images
During the last years, several high-resolution sensors have been developed for hyperspectral remote sensing applications.
Some of these sensors are already available on space-borne devices. Space-borne sensors are currently
acquiring a continual stream of hyperspectral data, and new efficient unsupervised algorithms are required to
analyze the great amount of data produced by these instruments. The identification of image endmembers is a
crucial task in hyperspectral data exploitation. Once the individual endmembers have been identified, several
methods can be used to map their spatial distribution, associations and abundances. This paper reviews the Pixel
Purity Index (PPI), N-FINDR and Automatic Morphological Endmember Extraction (AMEE) algorithms developed
to accomplish the task of finding appropriate image endmembers by applying them to real hyperspectral
data. In order to compare the performance of these methods a metric based on the Root Mean Square Error
(RMSE) between the estimated and reference abundance maps is used
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