706 research outputs found
Mining structured Petri nets for the visualization of process behavior
Visualization is essential for understanding the models obtained by process mining. Clear and efficient visual representations make the embedded information more accessible and analyzable. This work presents a novel approach for generating process models with structural properties that induce visually friendly layouts. Rather than generating a single model that captures all behaviors, a set of Petri net models is delivered, each one covering a subset of traces of the log. The models are mined by extracting slices of labelled transition systems with specific properties from the complete state space produced by the process logs. In most cases, few Petri nets are sufficient to cover a significant part of the behavior produced by the log.Peer ReviewedPostprint (author's final draft
Visualising the South Yorkshire floods of ‘07
This paper describes initial work on developing an information
system to gather, process and visualise various multimedia data sources related to the South Yorkshire (UK) floods of 2007. The work is part of the Memoir project which aims to investigate how technology can help people create and manage long-term personal memories. We are using maps to aggregate multimedia data and to stimulate remembering past events. The paper describes an initial prototype; challenges faced so far and planned future work
Evidencias sobre la eficacia de los corredores ecológicos: ¿Solucionan la problemática de fragmentación de hábitats?
Se realiza una revisión del estado de la cuestión con respecto al bagaje cientÃfico existente sobre la eficacia de los corredores ecológicos como elementos dirigidos a la conservación de especies en paisajes fragmentados. Previamente se enumeran los efectos potenciales positivos y negativos que pudieran tener los corredores sobre la vida silvestre y se describen las principales dificultades metodológicas que presentan los estudios que tienen como objetivo testar dicha eficacia. Se evidencia la existencia de un nivel probatorio creciente sobre los efectos positivos de corredores ecológicos de caracterÃsticas adecuadas en materia de conservación, si bien se espera que aumente significativamente el bagaje cientÃfico al respecto en los próximos años. El principio de precaución en materia de conectividad ecológica se torna fundamental dentro de la planificación territorial y sectorial, con el objeto de prevenir la pérdida de funcionalidad de los corredores ecológicos remanentes en el territorio.A review of scientific knowledge about the effectiveness of ecological corridors as elements aimed at the conservation of species in fragmented landscapes is conducted. Before, the potential positive and negative effects that corridors might have on wildlife are listed and the main methodological difficulties that show the studies that aim to test that effectiveness are described. It is clear that there is a growing level of evidence about the positive effects of ecological corridors of appropriate characteristics in terms of conservation, although it is expected that the scientific knowledge in this regard increase significantly in the coming years. The precautionary principle in the field of ecological connectivity becomes crucial in landscape planning, in order to prevent the loss of function of ecological corridors remaining in the territory.On réalise une révision de l’état de la question à l’égard du bagage scientifique existant sur l’efficacité des corridors écologiques, comme des éléments dirigés à la conservation d’espèces dans des paisajes fragmentés. Au préalable on énumère les effets potentiels positifs et négatives que peuvent avoir les corridors sur la vie sauvage et on décrit les difficultés principales méthodologiques que présentent les études qui ont pour but tèster la dite efficacité. Bien que les effets positifs des corridors écologiques adecuats sont évidents, on s’attend que le bagage scientifique à ce sujet augmente significativement dans les prochaines années. Le principe de précaution en matière de connectivité écologique deviene fondamental dans la planification territoriale et séctorielle, afin de prévenir la perte de fonctionnalité des corridors écologiques rémanents dans le territoire
A systematic review of Twitter’s hashtags in public health: an example of a globally adopted standard
The objective is to find evidence and make recommendations on the use of Twitter in public health,particularly through
the study of hashtags(#). This systematic review shows the use of Twitter in different areas of public health: epidemiological surveillance, health promotion, health protection and disease prevention. Articles on this subject published in indexed journals with impact factor show the importance of conversations to engage the attention of Twitter users by using citations (@ user) and retweets(RT); however, not much importance seems to be given to the use of hashtags(#), which are often assimilated to the concept of keywords. Although tracking recurring hashtagsshould be less expensive than computing Twitter content, the potential of hashtaggeddata has not been properly exploited or recognized over the past years, probably due to the lack of efficient tools
Schroedinger vs. Navier-Stokes
[EN] Quantum mechanics has been argued to be a coarse-graining of some underlying deterministic theory. Here we support this view by establishing a map between certain solutions of the Schroedinger equation, and the corresponding solutions of the irrotational Navier-Stokes equation for viscous fluid flow. As a physical model for the fluid itself we propose the quantum probability fluid. It turns out that the (state-dependent) viscosity of this fluid is proportional to Planck's constant, while the volume density of entropy is proportional to Boltzmann's constant. Stationary states have zero viscosity and a vanishing time rate of entropy density. On the other hand, the nonzero viscosity of nonstationary states provides an information-loss mechanism whereby a deterministic theory (a classical fluid governed by the Navier-Stokes equation) gives rise to an emergent theory (a quantum particle governed by the Schroedinger equation).Fernández De Córdoba, P.; Isidro San Juan, JM.; Vazquez Molina, J. (2016). Schroedinger vs. Navier-Stokes. Entropy. 18(1):1-11. doi:10.3390/e18010034S11118
A comparative study of two different approaches for the incorporation of silver nanoparticles into layer-by-layer films
UPNa. Departamento de IngenierÃa Eléctrica y Electrónica. Laboratorio de Dispositivos Ópticos NanoestructuradosIn this work, a comparative study about the incorporation of silver nanoparticles (AgNPs) into thin films is presented
using two alternative methods, the in situ synthesis process and the layer-by-layer embedding deposition technique.
The influence of several parameters such as color of the films, thickness evolution, thermal post-treatment, or
distribution of the AgNPs along the coatings has been studied. Thermal post-treatment was used to induce the
formation of hydrogel-like AgNPs-loaded thin films. Cross-sectional transmission electron microscopy micrographs,
atomic force microscopy images, and UV-vis spectra reveal significant differences in the size and distribution of the
AgNPs into the films as well as the maximal absorbance and wavelength position of the localized surface plasmon
resonance absorption bands before and after thermal post-treatment. This work contributes forThis work was supported by the Spanish Ministry of Economy and
Competitiveness through TEC2010-17805 Research Project, Innocampus
Program and Public University of Navarra (UPNA) research grants
Self-referenced optical fiber sensor for hydrogen peroxide detection based on LSPR of metallic nanoparticles in layer-by-layer films
Intensity-based optical fiber sensors are one of the most studied sensor approaches thanks to their simplicity and low cost. Nevertheless, their main issue is their lack of robustness since any light source fluctuation, or unexpected optical setup variation is directly transferred to the output signal, which, significantly reduces their reliability. In this work, a simple and robust hydrogen peroxide (H2O2) optical fiber sensor is proposed based on the Localized Surface Plasmon Resonance (LSPR) sensitivity of silver and gold metallic nanoparticles. The precise and robust detection of H2O2 concentrations in the ppm range is very interesting for the scientific community, as it is a pathological precursor in a wide variety of damage mechanisms where its presence can be used to diagnose important diseases such as Parkinson's disease, diabetes, asthma, or even Alzheimer's disease). In this work, the sensing principle is based the oxidation of the silver nanoparticles due the action of the hydrogen peroxide, and consequently the reduction of the efficiency of the plasmonic coupling. At the same time, gold nanoparticles show a high chemical stability, and therefore provide a stable LSPR absorption band. This provides a stable real-time reference that can be extracted from the spectral response of the optical fiber sensor, giving a reliable reading of the hydrogen peroxide concentration.This work has been supported by the Spanish Economy and Competitiveness TEC2016-78047-R grant and the PhD research grants of the Public University of Navarre
Biomimetic Ca-P coatings Incorporating bisphosphonates produced on starch-based degradable biomaterials
In this study, sodium clodronate, a well-known therapeutic agent from the family
of bisphosphonates (BPs), is incorporated in a biomimetic calcium phosphate (CaP) coating,
previously formed on the surface of a starch-based biomaterial by a sodium silicate
methodology, as a strategy to develop a site-specific drug delivery system for bone tissue
regeneration applications. The effects on the resulting CaP coatings were evaluated in terms of
morphology, chemistry, and structure. The dissolution of Ca and P from the coating and the
release profiles of sodium clodronate was also assessed. As a preliminary approach, this first
study also aimed at evaluating the effects of this BP on the viability of a human osteoblastic
cell line since there is still little information available on the interaction between BPs and this
type of cells. Sodium clodronate was successfully incorporated, at different doses, in the
structure of a biomimetic CaP layer previously formed by a sodium silicate process. This
type of BPs had a stimulatory effect on osteoblastic activity, particularly at the specific
concentration of 0.32 mg/mL. It is foreseen that these coatings can, for instances, be
produced on the surface of degradable polymers and then used for regulating the
equilibrium on osteoblastic/osteoclastic activity, leading to a controlled regenerative effect
at the interface between the biomaterial and bone
Entropy, Topological Theories and Emergent Quantum Mechanics
[EN] The classical thermostatics of equilibrium processes is shown to possess a quantum mechanical dual theory with a finite dimensional Hilbert space of quantum states. Specifically, the kernel of a certain Hamiltonian operator becomes the Hilbert space of quasistatic quantum mechanics. The relation of thermostatics to topological field theory is also discussed in the context of the approach of the emergence of quantum theory, where the concept of entropy plays a key role.Research supported by grant No. ENE2015-71333-R (Spain).Cabrera, D.; Fernández De Córdoba Castellá, PJ.; Isidro San Juan, JM.; Vazquez Molina, J. (2017). Entropy, Topological Theories and Emergent Quantum Mechanics. Entropy. 19(3). https://doi.org/10.3390/e19030087S19
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