Estudio comparativo de modelos de propagación con el análisis de la intensidad de la señal LTE de las estaciones base con el área de cobertura en Riobamba -Ecuador

This research paper presents the study of propagation models: Log-Normal, Okumura-Hata, Walfish-Bertoni, Walfish-Ikegami and SUI; through which a comparison will be made with the measurements made in different sectors in the city of Riobamba, for this study we will collaborate with the mobile operators Claro and Tuenti. For the respective measurements, random points are taken around the radio base with the help of the Network Cell Info-Lite cellular application with a minimum estimate of 50 data with their respective distance at three different times of the day in the morning, noon and afternoon, for this the study will be carried out in four sectors of the city, an average of the 50 extracted data will be calculated. The objective is to determine which model fits the previously mentioned propagation models, the results will be analyzed, and it will be interpreted which model fits each of the five proposed locations, considering the restrictions and parameters of each of the proposed propagation models.Este trabajo de investigación presenta el estudio de modelos de propagación: Log-Normal, Okumura-Hata, Walfish-Bertoni, Walfish-Ikegami y SUI; a través del cual se realizará una comparación con las mediciones realizadas en diferentes sectores de la ciudad de Riobamba, para este estudio trabajaremos con los operadores móviles Claro y Tuenti. Para las mediciones respectivas, se toman puntos aleatorios alrededor de la base de radio con la ayuda de la aplicación celular Network Cell Info-Lite con una estimación mínima de 50 datos con su respectiva distancia a tres momentos diferentes del día en la mañana, mediodía y tarde, para ello el estudio se realizará en cuatro sectores de la ciudad, se calculará un promedio de los 50 datos extraídos. El objetivo es determinar qué modelo se ajusta a los modelos de propagación mencionados anteriormente, se analizarán los resultados y se interpretará qué modelo se ajusta a cada una de las cinco ubicaciones propuestas, considerando las restricciones y parámetros de cada uno de los modelos de propagación propuestos

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements