New Approaches in Cognitive Radios using Evolutionary Algorithms

Cognitive radio has claimed a promising technology to exploit the spectrum in an ad hoc network. Due many techniques have become a topic of discussion on cognitive radios, the aim of this paper was developed a contemporary survey of evolutionary algorithms in Cognitive Radio. According to the art state, this work had been collected the essential contributions of cognitive radios with the particularity of base they research in evolutionary algorithms. The main idea was classified the evolutionary algorithms and showed their fundamental approaches. Moreover, this research will be exposed some of the current issues in cognitive radios and how the evolutionary algorithms will have been contributed. Therefore, current technologies have matters presented in optimization, learning, and classification over cognitive radios where evolutionary algorithms can be presented big approaches. With a more comprehensive and systematic understanding of evolutionary algorithms in cognitive radios, more research in this direction may be motivated and refined

Bio-inspired route estimation in cognitive radio networks

Cognitive radio is a technique that was originally created for the proper use of the radio electric spectrum due its underuse. A few methods were used to predict the network traffic to determine the occupancy of the spectrum and then use the ‘holes’ between the transmissions of primary users. The goal is to guarantee a complete transmission for the second user while not interrupting the trans-mission of primary users. This study seeks the multifractal generation of traffic for a specific radio electric spectrum as well as a bio-inspired route estimation for secondary users. It uses the MFHW algorithm to generate multifractal traces and two bio-inspired algo-rithms: Ant Colony Optimization and Max Feeding to calculate the secondary user’s path. Multifractal characteristics offer a predic-tion, which is 10% lower in comparison with the original traffic values and a complete transmission for secondary users. In fact, a hybrid strategy combining both bio-inspired algorithms promise a reduction in handoff. The purpose of this research consists on deriving future investigation in the generation of multifractal traffic and a mobility spectrum using bio-inspired algorithms

Exploración del desarrollo de habilidades investigativas en la infancia, a partir de la caracterización de los factores abióticos de un ecosistema terrestre

RESUMEN : El presente trabajo se propuso explorar del desarrollo de habilidades investigativas en la infancia, a partir de la caracterización de los factores abióticos de un ecosistema terrestre a través de la estrategia de investigación escolar, problemática que tuvo un enfoque cualitativo y se desarrolló desde el estudio de caso, que se centró en la descripción y el examen en profundidad de la unidad de análisis, que estuvo constituida por tres estudiantes. Para recolectar los datos se planificó y ejecutó una unidad didáctica que constó de seis fases. Los resultados fueron analizados a través de redes sistémicas, que dieron cuenta cómo a medida que se avanzó en el desarrollo de la unidad didáctica los participantes de la investigación, fueron ampliando su sistema descriptivo, analítico y de observación, esto se evidenció, comparando que en las fases iniciales de la unidad didáctica los participantes presentaron unas descripciones parciales en las que omitieron detalles y sus reflexiones estaban asociadas a un lenguaje común, ya para las fases finales, hacen descripciones de forma amplia, comprenden y utilizan las magnitudes de medidas para los instrumentos de medición de los factores abióticos que se abordaron

Paratuberculosis control strategies in dairy cattle: A systematic review

Background: Mycobacterium avium subsp. paratuberculosis is the causative agent of paratuberculosis (PTB), incurable enterocolitis, affecting domestic and wild ruminants. Economic losses, impacts on animal health and welfare, and public health concerns justify its herd-level control.Aim: To systematically collect information to answer: What are the control and eradication strategies of PTB in dairy cattle worldwide?Methods: The search procedure was carried out on October 2nd, 2019, and updated on August 3rd, 2021, using OVID®, SciELO, and Redalyc databases, and the registers from the International Colloquium on Paratuberculosis (1991–2018). The inclusion criteria considered articles published in English, Portuguese, and Spanish and in peerreviewed journals. The exclusion criteria included irrelevant topics, species other-than bovines, and not original articles. Definitive studies were obtained through the consensus of the authors on eligibility and quality. Data extraction was performed, considering bibliographic information, control and outcome strategies, follow-up time, and results.Results: Twenty-six relevant studies were found, reporting the use of three grouped control strategies: hygiene and management strategy (HMS), test-and-cull strategy (TCS), and vaccination strategy (VS). The HMS was the most common one (20/26), followed by TCS (17/26) and VS (7/26). Combined control strategies such as TCS-HMS (12/26), TCS-VS (1/26), and HMS-VS (1/26) were also described, and the consideration of the three control strategies (TCSHMS-VS) was reported in two articles. The HMS included practices such as neonates/juvenile livestock hygiene, biosecurity, prevention of infection introduction into the herd, and environmental management. Within HMS, the most frequent practices were to remove calves from their dams as soon as possible after birth and to keep the minimal exposure of calves and heifers to adult cattle. As limitations, within the HMS, it is considered that some strategies cannot be included due to lack of compliance, or the application of the same strategy among one study and another may have a different degree of interpretation; publication bias was not controlled since the results of the control programs in endemic countries may be not available.Conclusion: The main PTB control strategies in dairy cattle worldwide are HMS, TCS, and VS. The use of one or several combined strategies has been found to succeed in controlling the disease at the herd-level

A Multifractal Wavelet Model for the Generation of Lrd Traffic Traces With Adjustable Parameters

Las series de tiempo de trafico multifractal de longitud finita disponibles para realizar pruebas de desempeño de los algoritmos de gestión, control y admisión, y evaluación del grado de servicio sobre modelos M/M/1 para sistemas de comunicación WAN/LAN son muy pocas y su recolección a través de los mecanismos actuales es muy lenta debido a la cantidad de datos que se deben obtener. Por tanto, se hace necesario desarrollar una herramienta que sintetice trazas con características multifractales y que permita la configuración de sus parámetros estocásticos como su media, parámetro de Hurst, y ancho del espectro multifractal. El presente artículo describe el desarrollo de un algoritmo propuesto para generar series de tiempo de trafico multifractal de longitud finita con parámetro de Hurst y Ancho del espectro multifractal, muéstrales y ajustables, denominado MultiFractal Hurst Spectrum Width (MFHSW). El algoritmo MFHSW se basa en el modelo MultiFractal Hurst (MFH) y en el Modelo Wavelet Multifractal (MWM), para construir la serie de tiempo por medio de una cascada binomial multiplicativa, y ajustar el parámetro de Hurst y el ancho del espectro multifractal. La principal contribución del algoritmo MFHSW es permitir ajustar tanto el parámetro de Hurst como el ancho del espectro multifractal, lo cual se logra modificando adecuadamente las distribuciones beta que conforman la cascada binomial. En consecuencia el impacto que generar el desarrollo de un algoritmo para la generación de trazas con características multifractales será el de facilitar al investigador de un conjunto considerable de datos para la simulación y generación de escenarios de modelamiento de la red de datos. El algoritmo MFHW se comporta como un sistema experto al inferir la distribución de los coeficientes beta presentes en las escalas que conforman la cascada binomial a partir de los parámetros estocásticos configurados por el usuario, y obteniendo las correspondientes series de tiempo a través de un motor de inferencia. Para validar la efectividad del algoritmo se sintetiza una traza con parámetro de Hurst muestral y ancho del espectro multifractal similares a los que presenta una serie de tiempo de trafico de redes. El algoritmo MFHSW resulta ser una herramienta promisoria para el modelado de series de tiempo aplicable a diversos campos como la ingeniería de tráfico, las finanzas, las señales biomédicas, entre otras trazas reales con características multifractales.The available multifractal traffic finite-length time series to implement performance test of the management, control and admission algorithms, and level of service about M/M/1 models for WAN/LAN communication systems are very few and their recollection through current mechanisms is very slow due to the amount of data that must be obtained. Hence, it is necessary to develop a tool which synthesizes traces with multifractal features and allows the stochastic parameters configuration as its average, Hurst parameter and, multifractal spectrum width. This article describes the development of a proposed algorithm to generate multifractal traffic finite-length time series with a Hurst parameter and the multifractal spectrum width, sampling and adjustable, called MultiFractal Hurst Spectrum Width (MFHSW). The MFHSW algorithm is based on the MultiFractal Hurst model (MFH) and on the Multifractal Wavelet Model (MWM), to construct the time series through a binomial multiplicative cascade. The main contribution of the MFHSW algorithm is to allow adjusting both the Hurst parameter and the multifractal spectrum width, the aforementioned is achieved by appropriately modifying the beta distributions that conform the binomial cascade. Consequently, the impact developed by the algorithm to the trace generation with multifractal features will be the improvement in the simulation and data network modeling. The MFHW algorithm behaves as an expert system when inferring to distribution of the beta coefficients present in the scales that make part of the binomial cascade starting from the stochastic parameters configured by the user, and obtaining the corresponding time series through an inference engine. To validate the algorithm effectiveness, a trace with the Hurst parameter sampling and the multifractal spectrum width similar to the presented in a network traffic time series are synthetized. The MFHSW happens to be a promising tool for the modeling of time series applicable to diverse fields as the traffic engineering, finances, biomedical signals, among other real traces with multifractal features.Centro de Investigaciones de la Universidad Distrita

Memorias del primer Simposio Nacional de Ciencias Agronómicas

Primer simposio nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano

Memorias del primer Simposio Nacional de Ciencias Agronómicas

Primer simposio nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano