Detecting Falls as Novelties in Acceleration Patterns Acquired with Smartphones

Despite being a major public health problem, falls in the elderly cannot be detected efficiently yet. Many studies have used acceleration as the main input to discriminate between falls and activities of daily living (ADL). In recent years, there has been an increasing interest in using smartphones for fall detection. The most promising results have been obtained by supervised Machine Learning algorithms. However, a drawback of these approaches is that they rely on falls simulated by young or mature people, which might not represent every possible fall situation and might be different from older people's falls. Thus, we propose to tackle the problem of fall detection by applying a kind of novelty detection methods which rely only on true ADL. In this way, a fall is any abnormal movement with respect to ADL. A system based on these methods could easily adapt itself to new situations since new ADL could be recorded continuously and the system could be re-trained on the fly. The goal of this work is to explore the use of such novelty detectors by selecting one of them and by comparing it with a state-of-the-art traditional supervised method under different conditions. The data sets we have collected were recorded with smartphones. Ten volunteers simulated eight type of falls, whereas ADL were recorded while they carried the phone in their real life. Even though we have not collected data from the elderly, the data sets were suitable to check the adaptability of novelty detectors. They have been made publicly available to improve the reproducibility of our results. We have studied several novelty detection methods, selecting the nearest neighbour-based technique (NN) as the most suitable. Then, we have compared NN with the Support Vector Machine (SVM). In most situations a generic SVM outperformed an adapted NN

The effect of personalization on smartphone-based fall detectors

The risk of falling is high among different groups of people, such as older people, individuals with Parkinson''s disease or patients in neuro-rehabilitation units. Developing robust fall detectors is important for acting promptly in case of a fall. Therefore, in this study we propose to personalize smartphone-based detectors to boost their performance as compared to a non-personalized system. Four algorithms were investigated using a public dataset: three novelty detection algorithms—Nearest Neighbor (NN), Local Outlier Factor (LOF) and One-Class Support Vector Machine (OneClass-SVM)—and a traditional supervised algorithm, Support Vector Machine (SVM). The effect of personalization was studied for each subject by considering two different training conditions: data coming only from that subject or data coming from the remaining subjects. The area under the receiver operating characteristic curve (AUC) was selected as the primary figure of merit. The results show that there is a general trend towards the increase in performance by personalizing the detector, but the effect depends on the individual being considered. A personalized NN can reach the performance of a non-personalized SVM (average AUC of 0.9861 and 0.9795, respectively), which is remarkable since NN only uses activities of daily living for training

Exactitud en la Identificación de Caras y Tiempo de Respuesta: Face Identification Accuracy and Response Latency

El objetivo de este trabajo consistió en analizar en dos experimentos la relación existente entre la exactitud de la identificación de personas y el tiempo de respuesta. Para ello se presentó brevemente la fotografía de una persona desconocida. A continuación los sujetos realizaron una tarea distractora. Después trataron de reconocer a la persona objetivo, en una fotografía nueva, entre un conjunto de seis fotografías de personas de apariencia similar. Los resultados muestran que existe una amplia variabilidad en el tiempo de respuesta para las identificaciones correctas y las falsas alarmas. Sólo en el experimento 2, en el que se pidió a los sujetos que trataran de identificar a la persona objetivo en una tarea de elección forzosa, se encontraron diferencias significativas en el tiempo de respuesta en función del acierto. Los sujetos que acertaron tardaron menos tiempo en contestar que los sujetos que señalaron erróneamente a uno de los cebos de la rueda. En general, el tiempo de respuesta fue superior a los 10-12 segundos propuestos por Dunning y Perretta (2002) como tiempo límite para predecir las identificaciones correctas. Los resultados se analizan considerando sus posibles implicaciones en la valoración de la exactitud de los testigos en las pruebas de reconocimiento de sospechosos.[ABSTRACT] The aim of this project was to examine the relationship between the accuracy in the identification of persons and the response time, by means of two experiments. In the experiment 1 the subjects were presented a photographic image of an unknown person and then they were asked to perform a distracting task. Subsequently they tried to identify the target person in a new photography placed among a set of five images of persons of a similar appearance. The results showed that there is a large variability in the response time between correct identifications and false alarms. In the experiment 2 the subjects were asked to identify the target person in a forced choice assignment. In this test significant differences in the response time were found in relation to the right answer. The subjects that gave correct responses took less time in answering than the subjects that gave false alarms by choosing one of the foils in the lineup. In most cases the response time was higher than the 10-12 sec proposed by Dunning and Perretta (2002) as the time limit needed to predict the correct identifications. The results will be examined considering the possible implications regarding the evaluation of the eyewitnesses’ exactitude in the suspects’ recognition assignments

Fall Detection Analysis Using a Real Fall Dataset

International Conference on Soft Computing Models in Industrial and Environmental Applications (13th. 2018. San Sebastián

Polítiques educatives en contextos interculturals comunitaris

[cat] L’objectiu de la tesi és mostrar com es tradueixen en pràctiques les línies polítiques i normatives i com els diferents agents educatius de la comunitat articulen i planifiquen actuacions i condicions per dur a terme aquestes pràctiques. Aquesta tasca es realitza a partir de la descripció de les actuacions i les condicions que afavoreixen i dificulten la planificació i el desenvolupament de recursos educatius per a la interculturalitat i la inclusió social, des del punt de vista dels agents que conflueixen en un context educatiu de comunitat. La tesi es divideix en dues parts, la primera de les quals consta de cinc capítols: quatre on es fa la fonamentació teòrica i un cinquè on s’explica la fonamentació metodològica. Aquesta primera part inclou la fonamentació sobre el context de crisi global, i les polítiques socials i educatives per a la interculturalitat i la inclusió social i educativa. També s’hi fa una aproximació al discurs de l’educació intercultural i s’estudia el concepte de comunitat i el ressorgiment amb força de la idea de comunitat com a espai de trobada i espai on es produeixen mediacions educatives. Dins de la primera part, en l’apartat B, el capítol cinquè presenta la fonamentació metodològica de la tesi des de la metodologia qualitativa. D’altra banda, el mètode emprat és descriptiu en clau d’estudi de cas. Pel que fa al disseny de la recerca i a les tècniques per a la recollida de dades, per a la categorització i per a l’anàlisi de documents, són les pròpies de la recerca qualitativa: l’entrevista semiestructurada i l’anàlisi de documents. El procediment per convertir les dades qualitatives en coneixement ha consistit en la categorització de les unitats d’informació i l’anàlisi de contingut mitjançant el programari Nvivo. S’han categoritzat i codificat els plans per a la integració i la construcció de ciutadania i les entrevistes realitzades a agents que treballen en l’àmbit educatiu des dels centres educatius, a tècnics municipals d’educació i a entitats que treballen per millorar les condicions de vida en la comunitat. També s’han establert correlacions amb les dades primàries per tal de construir conceptes i relacions. Quant a la fiabilitat i la validesa de les dades, aquesta s’ha corroborat mitjançant l’ús del programari, la triangulació de les dades i la construcció de conjunts interrelacionats a partir del coeficient de Jacard. Els resultats de la recerca indiquen que els agents educatius que treballen en el dia a dia han dut a terme una tasca de planificació i acció educativa important, en l’àmbit escolar, socioeducatiu i comunitari. Els documents normatius i les polítiques han contribuït a aquesta tasca, atès que s’han optimitzat les metodologies de treball tot construint xarxes de treball conjunt amb la implicació dels agents de l’Administració i d’entitats del tercer sector. Cal continuar treballant des de l’educació intercultural comunitària per a la millora de la igualtat d’oportunitats, per a la construcció de les identitats complexes i per a la comunicació intercultural en un marc de construcció de la participació ciutadana.[eng] This thesis aims to show how political and regulatory guidelines are translated into practice and how different educational agents in the community articulate and develop actions and conditions to carry out those practices. It does so by describing, from the point of view of the different agents that come together in the educational context of the community, the actions and conditions that facilitate and impede the planning and development of educational resources for interculturality and social inclusion. The thesis is divided into two parts, the first consisting of five chapters: four that lay the theoretical groundwork and a fifth that details the methodological framework. The first part outlines the thesis’s foundation in the context of global crisis and the existing policies for social and educational interculturality and social and educational inclusion. It approximates the discourse on intercultural education and it situates the concept of community and the strong resurgence of the idea of community as the meeting place and space where educational mediations occur. The methodology employed is qualitative and the method is descriptive, looking at a case study and analysing the regulatory documents. Content analysis was employed for the data analysis and the program Nvivo was used for the treatment of the data, the plans for integration and construction of concepts of citizenship, and the interviews with agents that work in education in educational centres, municipal education employees and entities that work to improve quality of life in the community. The results of the research indicate that important work has been carried out by those involved in education on a day-to-day basis. Regulatory documents and policies have also contributed to this work because they have optimized working methodologies while constructing collaborative working networks with the implication of agents from local administration and third-sector entities. The intercultural community education sector must continue to work to improve equality of opportunity, the construction of complex identities, and intercultural communication within the framework of citizen participation. In the second part, Chapter Six presents the documentary analysis of the plans and programs for integration and the inclusion of immigration that have, over the past decades, oriented the actions of social and educational policy and the interrelation of the different sources analysed throughout the course of the research. It also describes the conceptual evolution of plans for the citizenry and for immigration, which are documents that arise from policy and also act as reference for new policies introduced for the integration and the inclusion of immigration in Catalonia. In this chapter, we lay out the fundamentals for the procedures and validate the results in relation to the context of the data from the different sources analysed and the methodology employed. In Chapter Seven, examples are presented of the data gathered from the interviews, with the aim of relating the original theoretical assumptions with the defined objectives, the established categories, and the contributions, evaluations and opinions of the different actors in relation to the research questions that were posed for the case study. This chapter also contains a final summary and conclusion section about the case study. The last chapter summarizes the conclusions from the data analysis and from the dialogue established with the different community actors, representatives of educational centres, local government employees and community agents, then goes on to make brief recommendations and set out possible lines of action for the generation of processes to strengthen the component of intercultural pedagogy in the community

FAPb0.5Sn0.5I3: A Narrow Bandgap Perovskite Synthesized through Evaporation Methods for Solar Cell Applications

The tunability of the optoelectrical properties upon compositional modification is a key characteristic of metal halide perovskites. In particular, bandgaps narrower than those in conventional lead‐based perovskites are essential to achieve the theoretical efficiency limit of single‐absorber solar cells, as well as develop multijunction tandem devices. Herein, the solvent‐free vacuum deposition of a narrow bandgap perovskite based on tin-lead metal and formamidinium cation is reported. Pinhole‐free films with 1.28 eV bandgap are obtained by thermal codeposition of precursors. The optoelectrical quality of these films is demonstrated by their use in solar cells with a power conversion efficiency of 13.98%

Practical considerations for acoustic source localization in the IoT era: Platforms, energy efficiency, and performance

The rapid development of the Internet of Things (IoT) has posed important changes in the way emerging acoustic signal processing applications are conceived. While traditional acoustic processing applications have been developed taking into account high-throughput computing platforms equipped with expensive multichannel audio interfaces, the IoT paradigm is demanding the use of more flexible and energy-efficient systems. In this context, algorithms for source localization and ranging in wireless acoustic sensor networks can be considered an enabling technology for many IoT-based environments, including security, industrial, and health-care applications. This paper is aimed at evaluating important aspects dealing with the practical deployment of IoT systems for acoustic source localization. Recent systems-on-chip composed of low-power multicore processors, combined with a small graphics accelerator (or GPU), yield a notable increment of the computational capacity needed in intensive signal processing algorithms while partially retaining the appealing low power consumption of embedded systems. Different algorithms and implementations over several state-of-the-art platforms are discussed, analyzing important aspects, such as the tradeoffs between performance, energy efficiency, and exploitation of parallelism by taking into account real-time constraintsThis work was supported in part by the Post-Doctoral Fellowship from Generalitat Valenciana under Grant APOSTD/2016/069, in part by the Spanish Government under Grant TIN2014-53495-R, Grant TIN2015-65277-R, and Grant BIA2016-76957-C3-1-R, and in part by the Universidad Jaume I under Project UJI-B2016-20.Publicad

Analytical Modeling is Enough for High Performance BLIS

We show how the BLAS-like Library Instantiation Software (BLIS) framework, which provides a more detailed layering of the GotoBLAS (now maintained as OpenBLAS) implementation, allows one to analytically determine tuning parameters for high-end instantiations of the matrix-matrix multiplication. This is of both practical and scientific importance, as it greatly reduces the development effort required for the implementation of the level-3 BLAS while also advancing our understanding of how hierarchically layered memories interact with high-performance software. This allows the community to move on from valuable engineering solutions (empirically autotuning) to scientific understanding (analytical insight).This research was sponsored in part by NSF grants ACI-1148125/1340293 and CCF-0917167. Enrique S. Quintana-Ortí was supported by project TIN2011-23283 of the Ministerio de Ciencia e Innovacióon and FEDER. Francisco D. Igual was supported by project TIN2012-32180 of the Ministerio de Ciencia e Innovación

Vacuum-Deposited Multication Tin-Lead Perovskite Solar Cells

The use of a combination of tin and lead is the most promising approach to fabricate narrow bandgap metal halide perovskites. This work presents the development of reproducible tin and lead perovskites by vacuum codeposition of the precursors, a solvent-free technique which can be easily implemented to form complex stacks. Crystallographic and optical characterization reveal the optimal film composition based on cesium and methylammonium monovalent cations. Device optimization makes use of the intrinsically additive nature of vacuum deposition, resulting in solar cells with 8.89% photovoltaic efficiency. The study of the devices by impedance spectroscopy identifies bulk recombination as one of the performance limiting factors