On the Design of Ambient Intelligent Systems in the Context of Assistive Technologies

The design of Ambient Intelligent Systems (AISs) is discussed in the context of assistive technologies. The main issues include ubiquitous communications, context awareness, natural interactions and heterogeneity, which are analyzed using some examples. A layered architecture is proposed for heterogeneous sub-systems integration with three levels of interactions that may be used as a framework to design assistive AISs.Ministerio de Ciencia y Tecnología TIC2001-1868-C0

SVMs for Automatic Speech Recognition: a Survey

Hidden Markov Models (HMMs) are, undoubtedly, the most employed core technique for Automatic Speech Recognition (ASR). Nevertheless, we are still far from achieving high-performance ASR systems. Some alternative approaches, most of them based on Artificial Neural Networks (ANNs), were proposed during the late eighties and early nineties. Some of them tackled the ASR problem using predictive ANNs, while others proposed hybrid HMM/ANN systems. However, despite some achievements, nowadays, the preponderance of Markov Models is a fact. During the last decade, however, a new tool appeared in the field of machine learning that has proved to be able to cope with hard classification problems in several fields of application: the Support Vector Machines (SVMs). The SVMs are effective discriminative classifiers with several outstanding characteristics, namely: their solution is that with maximum margin; they are capable to deal with samples of a very higher dimensionality; and their convergence to the minimum of the associated cost function is guaranteed. These characteristics have made SVMs very popular and successful. In this chapter we discuss their strengths and weakness in the ASR context and make a review of the current state-of-the-art techniques. We organize the contributions in two parts: isolated-word recognition and continuous speech recognition. Within the first part we review several techniques to produce the fixed-dimension vectors needed for original SVMs. Afterwards we explore more sophisticated techniques based on the use of kernels capable to deal with sequences of different length. Among them is the DTAK kernel, simple and effective, which rescues an old technique of speech recognition: Dynamic Time Warping (DTW). Within the second part, we describe some recent approaches to tackle more complex tasks like connected digit recognition or continuous speech recognition using SVMs. Finally we draw some conclusions and outline several ongoing lines of research

Synchronization in Random Geometric Graphs

In this paper we study the synchronization properties of random geometric graphs. We show that the onset of synchronization takes place roughly at the same value of the order parameter that a random graph with the same size and average connectivity. However, the dependence of the order parameter with the coupling strength indicates that the fully synchronized state is more easily attained in random graphs. We next focus on the complete synchronized state and show that this state is less stable for random geometric graphs than for other kinds of complex networks. Finally, a rewiring mechanism is proposed as a way to improve the stability of the fully synchronized state as well as to lower the value of the coupling strength at which it is achieved. Our work has important implications for the synchronization of wireless networks, and should provide valuable insights for the development and deployment of more efficient and robust distributed synchronization protocols for these systems.Comment: 5 pages, 4 figure

Data Balancing for Efficient Training of Hybrid ANN/HMM Automatic Speech Recognition Systems

Hybrid speech recognizers, where the estimation of the emission pdf of the states of Hidden Markov Models (HMMs), usually carried out using Gaussian Mixture Models (GMMs), is substituted by Artificial Neural Networks (ANNs) have several advantages over the classical systems. However, to obtain performance improvements, the computational requirements are heavily increased because of the need to train the ANN. Departing from the observation of the remarkable skewness of speech data, this paper proposes sifting out the training set and balancing the amount of samples per class. With this method the training time has been reduced 18 times while obtaining performances similar to or even better than those with the whole database, especially in noisy environments. However, the application of these reduced sets is not straightforward. To avoid the mismatch between training and testing conditions created by the modification of the distribution of the training data, a proper scaling of the a posteriori probabilities obtained and a resizing of the context window need to be performed as demonstrated in the paper.This work was supported in part by the regional grant (Comunidad Autónoma de Madrid-UC3M) CCG06-UC3M/TIC-0812 and in part by a project funded by the Spanish Ministry of Science and Innovation (TEC 2008-06382).Publicad

The hydration structure of Cu2+: More tetrahedral than octahedral?

A comprehensive multi-technique approach has been used to address the controversial question of the preferred geometric form of the Cu2+ aqua-ion hydration shell. A combination of H/D isotopic substitution neutron scattering and X-ray scattering has been used to refine atomistic models of 0.5 m and 2.0 m solutions of Cu(ClO4)2, that have also been constrained to simultaneously reproduce detailed local structure information about the cation environment obtained by X-ray Absorption spectroscopy. The adoption of the Empirical Potential Structure Refinement (EPSR) technique as a single unified analytical framework minimises the chances for biasing the result in favour of a specific pre-conceived outcome. The results are consistent with an average coordination for each Cu2+ ion of 4.5 ± 0.6 water molecules that matches the more recent picture of five-fold coordination in a 2.0 m solution, but interestingly this combined study highlights that the preferred local geometry of the ion sites is found to have a mixed character of tetrahedral, trigonal bipyramidal and octahedral components. A further point to note is that this new model adds support to a largely ignored result in the literature relating to the linear electric field effect induced g-shifts observed in the electron paramagnetic resonance spectra of glassy Cu2+ complexes (Peisach and Mims, Chem. Phys. Lett., 1976, 37, 307–310) that first highlighted the importance of tetrahedral distortions in the cation's hydration shell structure

Simulation and optimization of the CWPO process by combination of aspen plus and 6-factor doehlert matrix: Towards autothermal operation

This work aims to present an industrial perspective on CatalyticWet Peroxide Oxidation (CWPO) technology. Herein, process simulation and experimental design have been coupled to study the optimal process conditions to ensure high-performance oxidation, minimum H2O2 consumption and maximum energetic effciency in an industrial scale CWPO unit. The CWPO of phenol in the presence of carbon black catalysts was studied as a model process in the Aspen Plus® v11 simulator. The kinetic model implemented, based on 30 kinetic equations with 11 organic compounds and H2O2 involvement, was valid to describe the complex reaction network and to reproduce the experimental results. The computer experiments were designed on a six-factor Doehlert Matrix in order to describe the influence of the operating conditions (i.e., the different process temperatures, inlet chemical oxygen demands, doses of H2O2 and space time) on each selected output response (conversion, e ciency of H2O2 consumption and energetic effciency) by a quadratic model. The optimization of the WPO performance by a multi-criteria function highlighted the inlet chemical oxygen demand as the most influential operating condition. It needed to have values between 9.5 and 24 g L-1 for autothermal operation to be sustained under mild operating conditions (reaction temperature: 93–130 ºC and pressure: 1–4 atm) and with a stoichiometric dose of H2O2.The authors thank the financial support by the Spanish Government and Comunidad de Madrid through the projects CTM2016-76454-R and S2018/EMT-4341, respectively. Also, the authors acknowledge financial support to the Portugal Government through the project UIDB/00690/2020.info:eu-repo/semantics/publishedVersio

Cannabinoid CB₂ Receptor Modulation by the Transcription Factor NRF2 is Specific in Microglial Cells

Nuclear factor erythroid 2-related factor 2 (NRF2) is a pleiotropic transcription factor that has neuroprotective and anti-inflammatory effects, regulating more than 250 genes. As NRF2, cannabinoid receptor type 2 (CB2) is also implicated in the preservation of neurons against glia-driven inflammation. To this concern, little is known about the regulation pathways implicated in CB2 receptor expression. In this study, we analyze whether NRF2 could modulate the transcription of CB2 in neuronal and microglial cells. Bioinformatics analysis revealed an antioxidant response element in the promoter sequence of the CB2 receptor gene. Further analysis by chemical and genetic manipulations of this transcription factor demonstrated that NRF2 is not able to modulate the expression of CB2 in neurons. On the other hand, at the level of microglia, the expression of CB2 is NRF2-dependent. These results are related to the differential levels of expression of both genes regarding the brain cell type. Since modulation of CB2 receptor signaling may represent a promising therapeutic target with minimal psychotropic effects that can be used to modulate endocannabinoid-based therapeutic approaches and to reduce neurodegeneration, our findings will contribute to disclose the potential of CB2 as a novel target for treating different pathologies.This work was supported by the Spanish Ministry of Economy and Competitiveness (Grants Refs. SAF2016-76520-R to ILB and BFU2016-75973-R to MDG)

Leptolide improves insulin resistance in diet-induced obese mice

Producción CientíficaType 2 diabetes (T2DM) is a complex disease linked to pancreatic beta-cell failure and insulin resistance. Current antidiabetic treatment regimens for T2DM include insulin sensitizers and insulin secretagogues. We have previously demonstrated that leptolide, a member of the furanocembranolides family, promotes pancreatic beta-cell proliferation in mice. Considering the beneficial effects of leptolide in diabetic mice, in this study, we aimed to address the capability of leptolide to improve insulin resistance associated with the pathology of obesity. To this end, we tested the hypothesis that leptolide should protect against fatty acid-induced insulin resistance in hepatocytes. In a time-dependent manner, leptolide (0.1 µM) augmented insulin-stimulated phosphorylation of protein kinase B (PKB) by two-fold above vehicle-treated HepG2 cells. In addition, leptolide (0.1 µM) counteracted palmitate-induced insulin resistance by augmenting by four-fold insulin-stimulated phosphorylation of PKB in HepG2 cells. In vivo, acute intraperitoneal administration of leptolide (0.1 mg/kg and 1 mg/kg) improved glucose tolerance and insulin sensitivity in lean mice. Likewise, prolonged leptolide treatment (0.1 mg/kg) in diet-induced obese mice improved insulin sensitivity. These effects were paralleled with an ~50% increased of insulin-stimulated phosphorylation of PKB in liver and skeletal muscle and reduced circulating pro-inflammatory cytokines in obese mice. We concluded that leptolide significantly improves insulin sensitivity in vitro and in obese mice, suggesting that leptolide may be another potential treatment for T2DM.This research has been funded by Sociedad Española de Diabetes (Ayudas Investigación Básica 2014), Salud Castilla y León (BIO/VA40/15)Ministerio de Economía y Competitividad, (SAF2014-58702-C2-1-R),(SAF2014-58702-C2-2-R

Heat-pulse measurements of sap flow in olives for automating irrigation: tests, root flow and diagnostics of water stress

26 páginas, 10 figuras, 1 tabla, 32 referencias.-- [email protected] compensation heat-pulse method for measuring sap flow is tested here in olive trees (Olea europaea L.). We describe a rigorous three-way examination of the robustness of the technique for this species, and examine the potential of the technique for an automatic control of the irrigation system. Two tests were carried out using heat-pulse gear inserted into the stem of 12-year-old ‘Manzanilla’ olive trees. One test used forced-flow through a stem section, and the other involved measured water uptake by an excised tree. The measured sap flow in these two tests was in agreement with calculations from heat-pulse velocities when using a standard ‘wound correction’ to account for the presence of the probes and the disruption to the sap flow. Thus, this technique for monitoring transpiration can, we feel, be used with confidence in olives. The third experiment was carried out in the field, where we analysed sap flow data from two 29- year-old olive trees—one tree was under regular drip irrigation and the other was from dry-farming conditions. We use measurements of sap flow in the trunk to examine the hydraulic functioning of the tree, and to explore some diagnostics of water stress. Our heat-pulse measurements in the irrigated olive tree exhibited a profile of sap flow that was weighted towards the outer xylem of the tree trunk while the water-stressed trees in the field showed a profile of sap flow weighted towards the centre of the trunk. The loss of hydraulic functioning in the outermost section of the vascular system, as a result of water stress, we consider to be due both to stomatal control and to embolisms in the xylem vessels. The fourth experiment was also carried out in the field, in which sap flow measurements were made at three locations in the trunk as well as in two roots of another 29-year-old olive tree. The soil explored by each root, on opposite sides of the trunk, was differentially wetted by separate irrigation of each side. Our data showed that the surface roots were able to absorb water immediately after wetting, despite a reasonably prolonged period of moderate drought. Root activity quickly shifted to the regions where the soil had been wetted. A root in dry soil exhibited no flow at night, whereas sap flows of about 0.02 l h 1 were measured around midnight in the root drawing water from the wetter soil. Our observations suggest that the hydraulic behaviour of the trunk and surface roots might be used as a diagnostic of the onset, or severity, of water stress. Here there is not the imperative to replicate, for the prime goal is not transpiration estimation. Rather interpretation of the diurnal dynamics is used to infer the onset, or severity of water stress. The compensation heat-pulse seems a suitable technique for automatically controlling the irrigation system of olives, and probably other trees, based either on the estimation of the short-time dynamics of transpiration, or on changes in the hydraulic behaviour of the trees.The Comisión Interministerial de Ciencia y Tecnología of the Spanish Ministry of Education and Science financial support this project.Peer reviewe

Heat-pulse measurements of sap flow in olives for automating irrigation: tests, root flow and diagnostics of water stress

26 páginas, 10 figuras, 1 tabla, 32 referencias.-- [email protected] compensation heat-pulse method for measuring sap flow is tested here in olive trees (Olea europaea L.). We describe a rigorous three-way examination of the robustness of the technique for this species, and examine the potential of the technique for an automatic control of the irrigation system. Two tests were carried out using heat-pulse gear inserted into the stem of 12-year-old ‘Manzanilla’ olive trees. One test used forced-flow through a stem section, and the other involved measured water uptake by an excised tree. The measured sap flow in these two tests was in agreement with calculations from heat-pulse velocities when using a standard ‘wound correction’ to account for the presence of the probes and the disruption to the sap flow. Thus, this technique for monitoring transpiration can, we feel, be used with confidence in olives. The third experiment was carried out in the field, where we analysed sap flow data from two 29- year-old olive trees—one tree was under regular drip irrigation and the other was from dry-farming conditions. We use measurements of sap flow in the trunk to examine the hydraulic functioning of the tree, and to explore some diagnostics of water stress. Our heat-pulse measurements in the irrigated olive tree exhibited a profile of sap flow that was weighted towards the outer xylem of the tree trunk while the water-stressed trees in the field showed a profile of sap flow weighted towards the centre of the trunk. The loss of hydraulic functioning in the outermost section of the vascular system, as a result of water stress, we consider to be due both to stomatal control and to embolisms in the xylem vessels. The fourth experiment was also carried out in the field, in which sap flow measurements were made at three locations in the trunk as well as in two roots of another 29-year-old olive tree. The soil explored by each root, on opposite sides of the trunk, was differentially wetted by separate irrigation of each side. Our data showed that the surface roots were able to absorb water immediately after wetting, despite a reasonably prolonged period of moderate drought. Root activity quickly shifted to the regions where the soil had been wetted. A root in dry soil exhibited no flow at night, whereas sap flows of about 0.02 l h 1 were measured around midnight in the root drawing water from the wetter soil. Our observations suggest that the hydraulic behaviour of the trunk and surface roots might be used as a diagnostic of the onset, or severity, of water stress. Here there is not the imperative to replicate, for the prime goal is not transpiration estimation. Rather interpretation of the diurnal dynamics is used to infer the onset, or severity of water stress. The compensation heat-pulse seems a suitable technique for automatically controlling the irrigation system of olives, and probably other trees, based either on the estimation of the short-time dynamics of transpiration, or on changes in the hydraulic behaviour of the trees.The Comisión Interministerial de Ciencia y Tecnología of the Spanish Ministry of Education and Science financial support this project.Peer reviewe