Search results for "Networks"
showing 10 items of 3260 documents
Characterization of dual-polarization analogue radio over fiber fronthaul for LTE C-RAN architecture
2016
En este artículo se presentan los resultados de la medición ampliada de la radio analógica de doble polarización (DP) sobre fibra (RoF) en una arquitectura de red de acceso radio en la nube (C-RAN) de evolución a largo plazo (LTE). Esta técnica se propone para las conexiones de fibra entre las oficinas centrales y las estaciones base remotas. Se investigan varias longitudes de fibra óptica para determinar el mejor rendimiento del sistema en términos de magnitud de vector de error (EVM) y tasa de error de bit. La distancia máxima alcanzada para el caso de un ancho de banda LTE de 20 MHz es de 50 km, mostrando un valor de EVM admisible del 8,5% a la frecuencia de radio de 2,6 GHz cuando se ut…
Multicore Fiber Opportunities for Centralized Radio Access Networks
2014
Les arquitectures de ràdio sobre fibra concebudes per a la propera generació de sistemes d’accés sense fils es basen en xarxes d’accés a ràdio centralitzades (C-RAN), on els recursos de processament de banda base corresponents a diferents estacions base remotes (BS) s’allotgen en una oficina central compartida (CO). Proposem l'explotació de les característiques úniques que aporta el paral·lelisme inherent de les fibres de diversos nuclis com a solució compacta per implementar la connectivitat CO-BS necessària en C-RAN. JCI-2012-14805 PROMETEO II/2013/012 Radio-over-fiber architectures conceived for the next generation of wireless access systems are based on Centralized Radio Access Networks…
A Simulation Based Analysis of an Multi Objective Diffusive Load Balancing Algorithm
2018
In this paper, we presented a further development of our research on developing an optimal software-hardware mapping framework. We used the Petri Net model of the complete hardware and software High Performance Computing (HPC) system running a Computational Fluid Dynamics (CFD) application, to simulate the behaviour of the proposed diffusive two level multi-objective load-balancing algorithm. We developed an meta-heuristic algorithm for generating an approximation of the Pareto-optimal set to be used as reference. The simulations showed the advantages of this algorithm over other diffusive algorithms: reduced computational and communication overhead and robustness due to low dependence on u…
Social Interaction in YouTube Text-Based Polylogues: A Study of Coherence
2012
Since YouTube was launched, its emblematic video-sharing facility has attracted considerable attention as a social networking system of cultural production. In addition to vlogging, YouTube offers a text facility through which YouTubers share and negotiate opinions. However, research into the latter is scarce, especially within language-based disciplines (Androutsopoulos & Beiβwenger 2009; Zelenkauskaite & Herring 2008). This article contributes to addressing this imbalance by focusing on YouTube text-based ‘conversation’ (Herring 2010a). Specifically, it examines coherence in a corpus of YouTube postings in Spanish. Although coherence has been the object of much academic debate in other fo…
Using the Breeder genetic algorithm to optimize a multiple regression analysis model used in prediction of the mesiodistal width of unerupted teeth
2014
For the prediction of the unerupted canine and premolars mesiodistal size, have been proposed different variants of multiple linear regression equations (MLRE). These are based on the amount of the upper and lower permanent incisors with a tooth of the lateral support. Aim of present study was to develop a method for optimization of MLRE, using a genetic algorithm for determining a set of coefficients that minimizes the prediction error for the sum of permanent premolars and canines dimensions from a group of young people in an area Romania's central city represented by Sibiu. To test the proposed method, we used a multiple linear regression equation derived from the estimation method propo…
Researchers' Age, Gender and Professional Status as Indicators of the Twitter Perception in Science Dissemination
2019
Resumen: El objetivo de este estudio es evaluar el grado de satisfacción e interés que presenta el personal de investigación de las universidades españolas por las redes sociales como Twitter. Para ello, se han examinado los datos obtenidos mediante una encuesta online a unos 600 investigadores proactivos de la divulgación científica de 20 universidades españolas (2016). Para el análisis de los datos, se utilizó el test de independencia de Kruskal-Wallis. Según los resultados, dos de cada tres (65.4%) investigadores percibieron beneficios después de haber realizado la comunicación de sus resultados de investigación y una gran mayoría (84.7%) no percibieron ningún perjuicio. En relación con …
Bot recognition in a Web store: An approach based on unsupervised learning
2020
Abstract Web traffic on e-business sites is increasingly dominated by artificial agents (Web bots) which pose a threat to the website security, privacy, and performance. To develop efficient bot detection methods and discover reliable e-customer behavioural patterns, the accurate separation of traffic generated by legitimate users and Web bots is necessary. This paper proposes a machine learning solution to the problem of bot and human session classification, with a specific application to e-commerce. The approach studied in this work explores the use of unsupervised learning (k-means and Graded Possibilistic c-Means), followed by supervised labelling of clusters, a generative learning stra…
Impacts écologiques des formes d'urbanisation : modélisations urbaines et paysagères
2015
The global increase of urbanization during the past decades have induced a progressive artificialization of natural environments. The building of transport infrastructures and new housings causes a landscape fragmentation in an irreversible way and a strong decrease of the connectivity of ecological habitats. Maintaining the functionality of ecological networks is becoming a major goal of sustainable urban planning policies. With a special focus on urban evolutions in the horizon 2030 in the urban area of Besançon in eastern France (residential development and road traffic evolutions), this thesis aims to assess the potential impact of urban forms on landscape connectivity of animal species…
The cockroach Blattella germanica obtains nitrogen from uric acid through a metabolic pathway shared with its bacterial endosymbiont.
2014
Uric acid storedin the fat bodyof cockroaches is a nitrogen reservoirmobilized in times of scarcity. The discovery of urease in Blattabacterium cuenoti, the primary endosymbiont of cockroaches, suggests that the endosymbiont may participate in cockroach nitrogen economy. However, bacterial urease may only be one piece in the entire nitrogen recycling process from insect uric acid. Thus, in addition to the uricolytic pathway to urea, there must be glutamine synthetase assimilating the released ammonia by the urease reaction to enable the stored nitrogen to be metabolically usable. None of the Blattabacterium genomes sequenced to date possess genes encoding for those enzymes. To test the host…
CNN-Based Prostate Zonal Segmentation on T2-Weighted MR Images: A Cross-Dataset Study
2020
Prostate cancer is the most common cancer among US men. However, prostate imaging is still challenging despite the advances in multi-parametric magnetic resonance imaging (MRI), which provides both morphologic and functional information pertaining to the pathological regions. Along with whole prostate gland segmentation, distinguishing between the central gland (CG) and peripheral zone (PZ) can guide toward differential diagnosis, since the frequency and severity of tumors differ in these regions; however, their boundary is often weak and fuzzy. This work presents a preliminary study on deep learning to automatically delineate the CG and PZ, aiming at evaluating the generalization ability o…