The coalescing-branching random walk on expanders and the dual epidemic process

Information propagation on graphs is a fundamental topic in distributed computing. One of the simplest models of information propagation is the push protocol in which at each round each agent independently pushes the current knowledge to a random neighbour. In this paper we study the so-called coalescing-branching random walk (COBRA), in which each vertex pushes the information to $k$ randomly selected neighbours and then stops passing information until it receives the information again. The aim of COBRA is to propagate information fast but with a limited number of transmissions per vertex per step. In this paper we study the cover time of the COBRA process defined as the minimum time until each vertex has received the information at least once. Our main result says that if $G$ is an $n$-vertex $r$-regular graph whose transition matrix has second eigenvalue $\lambda$, then the COBRA cover time of $G$ is $\mathcal O(\log n )$, if $1-\lambda$ is greater than a positive constant, and $\mathcal O((\log n)/(1-\lambda)^3))$, if $1-\lambda \gg \sqrt{\log( n)/n}$. These bounds are independent of $r$ and hold for $3 \le r \le n-1$. They improve the previous bound of $O(\log^2 n)$ for expander graphs. Our main tool in analysing the COBRA process is a novel duality relation between this process and a discrete epidemic process, which we call a biased infection with persistent source (BIPS). A fixed vertex $v$ is the source of an infection and remains permanently infected. At each step each vertex $u$ other than $v$ selects $k$ neighbours, independently and uniformly, and $u$ is infected in this step if and only if at least one of the selected neighbours has been infected in the previous step. We show the duality between COBRA and BIPS which says that the time to infect the whole graph in the BIPS process is of the same order as the cover time of the COBRA proces

Formulation of a project to Manage Physical Resources Available in the Land Transport Logistics

El objetivo del presente documento es mostrar el desarrollo de un proyecto que permite la optimización de los recursos logísticos, reduciendo los costos de distribución y abastecimiento de materiales para una operación. Con un análisis de las rutas y los recursos físicos disponibles, se identifican áreas de oportunidad, para desarrollar y evaluar una propuesta que unifica recursos de diferentes operaciones, reduciendo a su vez la necesidad de los mismos; finalmente se evalúa la propuesta desde la parte económica, revisando tanto la inversión a realizar como el retorno de esta, bajo los estándares de aceptación exigidos por la operaciónThe purpose of this paper is to show the development of a project that allows the optimization of logistics resources, reducing distribution costs and supply of materials for an operation. With an analysis of the routes and physical resources, identify areas of opportunity to develop and evaluate a proposal that unifies resources from different operations, while reducing the need for them; Finally the proposal is evaluated from the economic side, reviewing both the investment required and the return of this, under the standards of acceptance required by the operatio

Detecting fish aggregations from reef habitats mapped with high resolution side scan sonar imagery

As part of a multibeam and side scan sonar (SSS) benthic survey of the Marine Conservation District (MCD) south of St. Thomas, USVI and the seasonal closed areas in St. Croix—Lang Bank (LB) for red hind (Epinephelus guttatus) and the Mutton Snapper (MS) (Lutjanus analis) area—we extracted signals from water column targets that represent individual and aggregated fish over various benthic habitats encountered in the SSS imagery. The survey covered a total of 18 km2 throughout the federal jurisdiction fishery management areas. The complementary set of 28 habitat classification digital maps covered a total of 5,462.3 ha; MCDW (West) accounted for 45% of that area, and MCDE (East) 26%, LB 17%, and MS the remaining 13%. With the exception of MS, corals and gorgonians on consolidated habitats were significantly more abundant than submerged aquatic vegetation (SAV) on unconsolidated sediments or unconsolidated sediments. Continuous coral habitat was the most abundant consolidated habitat for both MCDW and MCDE (41% and 43% respectively). Consolidated habitats in LB and MS predominantly consisted of gorgonian plain habitat with 95% and 83% respectively. Coral limestone habitat was more abundant than coral patch habitat; it was found near the shelf break in MS, MCDW, and MCDE. Coral limestone and coral patch habitats only covered LB minimally. The high spatial resolution (0.15 m) of the acquired imagery allowed the detection of differing fish aggregation (FA) types. The largest FA densities were located at MCDW and MCDE over coral communities that occupy up to 70% of the bottom cover. Counts of unidentified swimming objects (USOs), likely representing individual fish, were similar among locations and occurred primarily over sand and shelf edge areas. Fish aggregation school sizes were significantly smaller at MS than the other three locations (MCDW, MCDE, and LB). This study shows the advantages of utilizing SSS in determining fish distributions and density

Adaptación tecnológica de una máquina recuperadora de glp residual en tanques domésticos aplicación del modelo de dispersion

El presente trabajo tiene como fin el dimensionamiento de un sistema para la recuperación del GLP residual existente en los cilindros domésticos, con una capacidad de evacuación de 1.200 unidades diarias. Se inicia el trabajo a partir del análisis de información obtenida de sistemas utilizados en plantas de mantenimiento de cilindros para GLP, mediante la cual se definen los componentes del sistema. Posteriormente se genera un modelo del comportamiento del fluido al momento de evacuarlo del cilindro para estimar el tiempo que se requiere por unidad y la estimación de las capacidades de cada uno de los elementos constituyentes. Una vez obtenida esta información se procede a la selección de los equipos. Los objetivos deseados son: presentar una solución que reduzca las emisiones de GLP al medio ambiente, minimizando el riesgo potencial de existencia de áreas explosivas; mejorar las condiciones de trabajo de los operarios, evitando la inhalación de estos vapores; y, realizar un análisis económico que nos permita evaluar los costos y posibles beneficios que puede generar la ejecución de este proyecto

Prospective Scenarios on Energy Efficiency and CO2 Emissions in the EU Iron & Steel Industry

This document analyzes on the basis of a detailed bottom-up model the role of technology and its diffusion on energy consumption and CO2 emissions at plant level in the EU-27 Iron & Steel industry. Main current processes of all plants and the cost-effectiveness of their retrofit with Best Available Technologies and Innovative Technologies is analyzed up to 2030. The baseline scenario considers the demand for steel and prices of fuels and resources evolve according to the projection of Primes. Two alternative scenarios vary linearly several times by 2030 some of the main drives of technology change, such us the cost of CO2 allowances, fuels and price of the resources. The reduction ranges for the specific CO2 emissions varies between 14% and 21%. The range for the variation in specific energy consumption goes from 7 to 11%. The higher values rely on the successful market roll-out by 2020 of some key innovative technologies, underlining the importance of the successful conclusion of the research ongoing in those technologies. In the recycling route the results indicate potential improvements between 2010 and 2030 in the specific energy consumption and specific CO2 emissions of about 6% and 11%, respectively.JRC.F.6-Energy systems evaluatio

Análisis de los parámetros y selección de hornos para la combustión de biomasa

El presente estudio fue realizar una estimación analítica de los parámetros necesarios para poder operar un horno de combustión en condiciones óptimas para cuando utilizamos residuos agrícolas tales como: bagazo de caña, cascarilla de arroz y cascarilla de café como un combustible alterno. Para estimar estos parámetros utilicé ecuaciones basadas en la termodinámica de la combustión y ecuaciones empíricas. Al final de este estudio obtuve valores estimados de los parámetros tales como: temperatura adiabática de llama, relación aire/combustible y tiempo de residencia. Adicionalmente a lo anterior también seleccione el tipo de horno para cada biomasa. Para poder saber que tan exactos fueron los parámetros teóricos obtenidos, realicé una comparación con otro método analítico que me permitió determinar el porcentaje de error. Adicionalmente elaboré unas gráficas que me permitieron saber el comportamiento de las biomasas en el proceso de combustión al variar los parámetros

Kernelized Stein Discrepancy Tests of Goodness-of-fit for Time-to-Event Data

Survival Analysis and Reliability Theory are concerned with the analysis of time-to-event data, in which observations correspond to waiting times until an event of interest such as death from a particular disease or failure of a component in a mechanical system. This type of data is unique due to the presence of censoring, a type of missing data that occurs when we do not observe the actual time of the event of interest but, instead, we have access to an approximation for it given by random interval in which the observation is known to belong. Most traditional methods are not designed to deal with censoring, and thus we need to adapt them to censored time-to-event data. In this paper, we focus on non-parametric goodness-of-fit testing procedures based on combining the Stein's method and kernelized discrepancies. While for uncensored data, there is a natural way of implementing a kernelized Stein discrepancy test, for censored data there are several options, each of them with different advantages and disadvantages. In this paper, we propose a collection of kernelized Stein discrepancy tests for time-to-event data, and we study each of them theoretically and empirically; our experimental results show that our proposed methods perform better than existing tests, including previous tests based on a kernelized maximum mean discrepancy.Comment: Proceedings of the International Conference on Machine Learning, 202

Proceso de implementación de un sistema de producción más limpia en una empacadora de camarones

Producción más limpia (PML) significa aplicar una estrategia preventiva integral a los procesos, productos y servicios para incrementar la eficiencia y reducir los riesgos para las personas y el ambiente. Para la implementación se debió primeramente establecer un equipo de trabajo, luego se hizo un reconocimiento completo del proceso, seguido de un balance de materia y energía en el área de Shell On. Para identificar oportunidades de PML, se procedió a utilizar una matriz de impactos ambientales donde se analiza la severidad de los impactos, la probabilidad de contaminación y medidas para la reducción de los impactos, determinando la prioridad de las medidas y actuaciones a tomar por la empresa. Una vez determinada la prioridad de los casos se hace un estudio detallado de casos problema en este estudio se incluye identificación de los principales indicadores, análisis económicos y beneficios ambientales. Finalmente se establecen las conclusiones y recomendaciones

Best-of-Three Voting on Dense Graphs

Given a graph $G$ of $n$ vertices, where each vertex is initially attached an opinion of either red or blue. We investigate a random process known as the Best-of-three voting. In this process, at each time step, every vertex chooses three neighbours at random and adopts the majority colour. We study this process for a class of graphs with minimum degree $d = n^{\alpha}$\,, where $\alpha = \Omega\left( (\log \log n)^{-1} \right)$. We prove that if initially each vertex is red with probability greater than $1/2+\delta$, and blue otherwise, where $\delta \geq (\log d)^{-C}$ for some $C>0$, then with high probability this dynamic reaches a final state where all vertices are red within $O\left( \log \log n\right) + O\left( \log \left( \delta^{-1} \right) \right)$ steps.European Research Counci

Trabajo del respeto con los estudiantes del grado 402 del Instituto Técnico Industrial Francisco José de Caldas mediante la educación física

El contexto del problema que se da con las clases prácticas virtuales hechas en el Colegio a lo largo de tres semestres y los antecedentes propiamente investigados; Gracias a esto se propone la pregunta de investigación, junto con sus objetivos que se dividen en dos y estos son los objetivo general y los objetivos específicos que es diseñar estrategias metodológicas para abordar el valor del respeto mediante la clase de educación física, y sus objetivos específicos es el conocer que está en la parte del marco referencial, definir e implementar que se encuentran en la los instrumentos y propuesta didáctica de investigación.Facultad de Derecho - Centro De Investigaciones Sociojurídica