Multiple Avalanches Across the Metal-Insulator Transition of Vanadium Oxide Nano-scaled Junctions

The metal insulator transition of nano-scaled $VO_2$ devices is drastically different from the smooth transport curves generally reported. The temperature driven transition occurs through a series of resistance jumps ranging over 2 decades in amplitude, indicating that the transition is caused by avalanches. We find a power law distribution of the jump amplitudes, demonstrating an inherent property of the $VO_2$ films. We report a surprising relation between jump amplitude and device size. A percolation model captures the general transport behavior, but cannot account for the statistical behavior.Comment: 4 papers and 4 figures submitted to PR

Enabling preemptive multiprogramming on GPUs

GPUs are being increasingly adopted as compute accelerators in many domains, spanning environments from mobile systems to cloud computing. These systems are usually running multiple applications, from one or several users. However GPUs do not provide the support for resource sharing traditionally expected in these scenarios. Thus, such systems are unable to provide key multiprogrammed workload requirements, such as responsiveness, fairness or quality of service. In this paper, we propose a set of hardware extensions that allow GPUs to efficiently support multiprogrammed GPU workloads. We argue for preemptive multitasking and design two preemption mechanisms that can be used to implement GPU scheduling policies. We extend the architecture to allow concurrent execution of GPU kernels from different user processes and implement a scheduling policy that dynamically distributes the GPU cores among concurrently running kernels, according to their priorities. We extend the NVIDIA GK110 (Kepler) like GPU architecture with our proposals and evaluate them on a set of multiprogrammed workloads with up to eight concurrent processes. Our proposals improve execution time of high-priority processes by 15.6x, the average application turnaround time between 1.5x to 2x, and system fairness up to 3.4x.We would like to thank the anonymous reviewers, Alexan- der Veidenbaum, Carlos Villavieja, Lluis Vilanova, Lluc Al- varez, and Marc Jorda on their comments and help improving our work and this paper. This work is supported by Euro- pean Commission through TERAFLUX (FP7-249013), Mont- Blanc (FP7-288777), and RoMoL (GA-321253) projects, NVIDIA through the CUDA Center of Excellence program, Spanish Government through Programa Severo Ochoa (SEV-2011-0067) and Spanish Ministry of Science and Technology through TIN2007-60625 and TIN2012-34557 projects.Peer ReviewedPostprint (author’s final draft

Improved predictions of the geographic distribution of invasive plants using climatic niche models

"Climatic niche models for invasive plants are usually constructed with occurrence records taken from literature and collections. Because these data neither discriminate among life-cycle stages of plants (adult or juvenile) nor the origin of individuals (naturally established or man-planted), the resulting models may mispredict the distribution ranges of these species. We propose that more accurate predictions could be obtained by modelling climatic niches with data of naturally established individuals, particularly with occurrence records of juvenile plants because this would restrict the predictions of models to those sites where climatic conditions allow the recruitment of the species. To test this proposal, we focused on the Peruvian peppertree (Schinus molle), a South American species that has largely invaded Mexico. Three climatic niche models were constructed for this species using high-resolution dataset gathered in the field. The first model included all occurrence records, irrespective of the life-cycle stage or origin of peppertrees (generalized niche model). The second model only included occurrence records of naturally established mature individuals (adult niche model), while the third model was constructed with occurrence records of naturally established juvenile plants (regeneration niche model). When models were compared, the generalized climatic niche model predicted the presence of peppertrees in sites located farther beyond the climatic thresholds that naturally established individuals can tolerate, suggesting that human activities influence the distribution of this invasive species. The adult and regeneration climatic niche models concurred in their predictions about the distribution of peppertrees, suggesting that naturally established adult trees only occur in sites where climatic conditions allow the recruitment of juvenile stages. These results support the proposal that climatic niches of invasive plants should be modelled with data of naturally established individuals because this improves the accuracy of predictions about their distribution ranges.

Growth-Induced In-Plane Uniaxial Anisotropy in V2_{2}O3_{3}/Ni Films

We report on a strain-induced and temperature dependent uniaxial anisotropy in V$_{2}$O$_{3}$/Ni hybrid thin films, manifested through the interfacial strain and sample microstructure, and its consequences on the angular dependent magnetization reversal. X-ray diffraction and reciprocal space maps identify the in-plane crystalline axes of the V$_{2}$O$_{3}$; atomic force and scanning electron microscopy reveal oriented rips in the film microstructure. Quasi-static magnetometry and dynamic ferromagnetic resonance measurements identify a uniaxial magnetic easy axis along the rips. Comparison with films grown on sapphire without rips shows a combined contribution from strain and microstructure in the V$_{2}$O$_{3}$/Ni films. Magnetization reversal characteristics captured by angular-dependent first order reversal curve measurements indicate a strong domain wall pinning along the direction orthogonal to the rips, inducing an angular-dependent change in the reversal mechanism. The resultant anisotropy is tunable with temperature and is most pronounced at room temperature, which is beneficial for potential device applications

Suport i automatització de l'administració d'un Data Lake

Un Data Lake és un repositori massiu de dades en el seu format original. Aquest TFG parteix d'una arquitectura de dades d'aquest tipus, en la que una API implementa el procés de governament de les dades entre les diferents zones del Data Lake. Com es pot implementar un sistema que permeti als usuaris gestionar aquest procés? La solució que planteja el TFG Suport i automatització de l'administració d'un Data Lake és, mitjançant l'API existent, desenvolupar una eina web genèrica que permeti als usuaris administrar el Data Lake i gestionar l'accés als recursos que l'API ofereix, simplificant així la gestió de les dades dels projectes que fan ús del Data Lake.A Data Lake is a massive repository of data in its original format. This TFG departs from such a data architecture, in which an API implements the data governance process between the different zones of the Data Lake. How can a system that allows users to manage this process be implemented? The solution proposed by the TFG Suport i automatització de l'administració d'un Data Lake is, using the existing API, to develop a generic web tool that allows users to administer the Data Lake and manage the access to the resources that the API offers, thus simplifying the management of the data of the projects that make use of the Data Lake

Local Certification of Some Geometric Intersection Graph Classes

In the context of distributed certification, the recognition of graph classes has started to be intensively studied. For instance, different results related to the recognition of planar, bounded tree-width and $H$-minor free graphs have been recently obtained. The goal of the present work is to design compact certificates for the local recognition of relevant geometric intersection graph classes, namely interval, chordal, circular arc, trapezoid and permutation. More precisely, we give proof labeling schemes recognizing each of these classes with logarithmic-sized certificates. We also provide tight logarithmic lower bounds on the size of the certificates on the proof labeling schemes for the recognition of any of the aforementioned geometric intersection graph classes

Body Control Module using the SAM-V71 development board

The Body Control Module is one of the main devices inside a car since it is responsible of the critical aspects for the correct function of the vehicle including the safety and comfort of all passengers. However, these features come at a high cost. Therefore, the aim of this project was to perform a BCM capable of executing the basic functions of a commercial module in a car but with a lower cost. This was achieved using the SAMV71 development board and its embedded CAN protocol communication port and following the V-cycle which has two main branches: planning and integration of their parts and validation. This model facilitates keeping track of any progress during the development stage. The device successfully read analog and digital inputs, processed the information and sent it through the CAN bus for further processing. AUTOSAR was the standard used trough the development process, since it is the most employed in the automotive industry. It specifies that the software components shall be in layers, helping the process of integration and giving portability to the project. With this BCM it is possible to adapt a classic internal combustion engine car that lacks modern electronics to a battery electric vehicle

Lactancia materna y su relación con el desarrollo cognitivo en niños de 7 a 10 años, comuna Sitio Nuevo, 2022

La lactancia Materna es el alimento ideal para los lactantes, es segura, limpia, además, contiene anticuerpos que protegen de muchas enfermedades propias de la infancia, reduce la morbilidad y la mortalidad, así como el riesgo de enfermedades crónicas y mejora El objetivo de la investigación fue, determinar la relación entre la lactancia materna y el desarrollo cognitivo en niños de 7 a 10 años, Comuna Sitio Nuevo. El diseño metodológico fue no experimental de corte trasversal con un enfoque cuantitativo y método deductivo. La población consto de 42 niños y niñas en conjunto con sus madres, mismos que viven en la comunidad, ubicados en el barrio 1 de Noviembre y 13 de Mayo. Como instrumentos de recolección de datos se utilizó el IMC en los niños, preguntas de la Normativa ESAMYN y el Test de evaluación cognitiva de Montreal (MoCA). Para el análisis de los resultados se trabajó con el programa Excel. Los resultados mostraron el 42% de las madres no saben cómo dar lactancia materna y el tiempo de lactancia fue del 29% de 6 a 9 meses, el 62% niños y el 50% de niñas están con probable trastorno cognitivo. Para concluir se afirmó que la lactancia Materna estuvo relacionada con el desarrollo cognitivo de los niños, por lo que es necesario la capacitación por parte de las entidades de salud para mejorar estas falencias