Geometric Aspects of Holographic Bit Threads

We revisit the recent reformulation of the holographic prescription to compute entanglement entropy in terms of a convex optimization problem, introduced by Freedman and Headrick. According to it, the holographic entanglement entropy associated to a boundary region is given by the maximum flux of a bounded, divergenceless vector field, through the corresponding region. Our work leads to two main results: (i) We present a general algorithm that allows the construction of explicit thread configurations in cases where the minimal surface is known. We illustrate the method with simple examples: spheres and strips in vacuum AdS, and strips in a black brane geometry. Studying more generic bulk metrics, we uncover a sufficient set of conditions on the geometry and matter fields that must hold to be able to use our prescription. (ii) Based on the nesting property of holographic entanglement entropy, we develop a method to construct bit threads that maximize the flux through a given bulk region. As a byproduct, we are able to construct more general thread configurations by combining (i) and (ii) in multiple patches. We apply our methods to study bit threads which simultaneously compute the entanglement entropy and the entanglement of purification of mixed states and comment on their interpretation in terms of entanglement distillation. We also consider the case of disjoint regions for which we can explicitly construct the so-called multi-commodity flows and show that the monogamy property of mutual information can be easily illustrated from our constructions.Comment: 48 pages, multiple figures. v3: matches published versio

Damage identification in structural health monitoring: a brief review from its implementation to the Use of data-driven applications

The damage identification process provides relevant information about the current state of a structure under inspection, and it can be approached from two different points of view. The first approach uses data-driven algorithms, which are usually associated with the collection of data using sensors. Data are subsequently processed and analyzed. The second approach uses models to analyze information about the structure. In the latter case, the overall performance of the approach is associated with the accuracy of the model and the information that is used to define it. Although both approaches are widely used, data-driven algorithms are preferred in most cases because they afford the ability to analyze data acquired from sensors and to provide a real-time solution for decision making; however, these approaches involve high-performance processors due to the high computational cost. As a contribution to the researchers working with data-driven algorithms and applications, this work presents a brief review of data-driven algorithms for damage identification in structural health-monitoring applications. This review covers damage detection, localization, classification, extension, and prognosis, as well as the development of smart structures. The literature is systematically reviewed according to the natural steps of a structural health-monitoring system. This review also includes information on the types of sensors used as well as on the development of data-driven algorithms for damage identification.Peer ReviewedPostprint (published version

Uso de la inmunohistoquímica como herramienta epidemiológica para el diagnóstico de rabia bovina a partir de casos no conclusivos

Objetivo. Identificar el virus de la rabia en casos de encefalitis bovina a partir de muestras archivadas en el laboratorio sin diagnóstico conclusivo. Materiales y métodos. Doce muestras de cerebro bovino sospechosas de rabia, fueron procesadas por la técnica de inmunoperoxidasa indirecta, usando anticuerpos policlonales contra el agente viral. Resultados. Se demostró la presencia de antígenos virales en tres casos en forma de agregados pequeños en el citoplasma de las neuronas, con un patrón de forma redonda u oval y un número variable de corpúsculos de inclusión viral. Se discute sobre la importancia de los resultados en Colombia, la utilidad de la técnica en las difíciles condiciones de envío de muestras al laboratorio, además la posible relación de los casos negativos con herpesvirus bovino 5. Conclusiones. La utilización de la técnica de inmunohistoquímica para demostrar antígenos del virus rábico en encéfalos bovinos fijados en formol, puede ayudar en el perfeccionamiento del mapa epidemiológico de la enfermedad de la rabia en Colombia y puede disminuir el alto subdiagnóstico de otras enfermedades que afectan el sistema nervioso de los bovinos

Spectrum sharing in cognitive radio networks

Cognitive radio networks are the next step to tackle scarcity in wireless networks given the increasing demand of radioelectric spectrum where the proposed solution is to share said resource to improve this situation. In the present article, a review of the current state of spectrum sharing in cognitive radio networks. To achieve this purpose, the articles published over the last 4 years on the matter were reviewed including topics such as mobile networks and TV. Some studies and simulations proposed to share the spectrum is shown. The current state of the studies reveals that there has been significant progress in this research area yet it is necessary to continue similar studies and set in motion different schemes

Fast Parallel Algorithm for audio content retrieval on GPUs.

The search techniques audio content MIR (music information retrieval) face two major challenges: the robustness of the algorithm and the speed of this operation. In this article proposes a model of fast algorithm for the extraction of audio data by the fingerprinting technique, which is implemented on a CPU-based platform and then parallelized to run on a graphics hardware (GPU). Tests on GPU determined a success rate close to 100% and response times approximately 2 times lower than those obtained with a PC workstation, allowing searches of up to 65 commercial in real-time.http://unidadinvestigacion.usta.edu.c

Fast parallel audio fingerprinting implementation in reconfigurable hardware and gpus

One of the main challenges that Music Information Retrieval (MIR) faces is performance. This paper presents an algorithm based on fingerprinting techniques implemented in a low-cost embedded reconfigurable platform. This fast algorithm is even faster when implemented in parallel for a GPU platform. The hit rate of the implementations is practically 100 % and the response time is two times faster than the response time of a top class PC, which means MIR times of up to 65 audio tracks in real time.http://unidadinvestigacion.usta.edu.c

Aplicación de gestión de mantenimiento preventivo para mejorar la productividad de la empresa Cinemark del Perú S.R.L, San Miguel, 2019

La presente investigación tuvo como objetivo principal determinar como la aplicación de gestión de mantenimiento preventivo mejora la productividad en el área de confitería de la empresa Cinemark del Perú S.R. L., para ello se implementó la disponibilidad, confiabilidad y mantenibilidad. Fue una investigación aplicada, de diseño cuasi-experimental. La población y la muestra fueron las maquinas pon corn en el área de confitería. La técnica empleada fue la observación, el instrumento fue la ficha de recolección de datos. La validación de los instrumentos se realizó a través del criterio de juicio de expertos. Para el análisis de los datos se utilizó el programa estadístico SPSS versión 25. Los resultados encontrados fueron: la productividad resultó 44.19 %; un valor menor luego de aplicar el nuevo método de trabajo que fue de 69.64 %; se concluyó que la aplicación de gestión de mantenimiento preventivo generó una mejora de 25.45 % en la productividad, en la empresa Cinemark 2019. Se recomendó seguir los procedimientos de mantenimiento preventivo, cumplir los cronogramas de mantenimiento para no presentar averías, determinando fallas a tiempo y poder contar con todos los equipos disponibles, a su vez ser eficientes en los servicios de mantenimiento y cumplir con lo establecido

A Model to Determine the Propagation Losses Based on the Integration of Hata-Okumura and Wavelet Neural Models

Radioelectric spectrum occupancy forecast has proven useful for the design of wireless systems able to harness spectrum opportunities like cognitive radio. This paper proposes the development of a model that identifies propagation losses and spectrum opportunities in a channel of a mobile cellular network for an urban environment using received signal power forecast. The proposed model integrates the Hata-Okumura (H-O) large-scale propagation model with a wavelet neural model. The model results, obtained through simulations, show that the wavelet neural model forecasts with a high degree of precision, which is consistent with the observed behavior in experiments carried out in wireless systems of this type