Search results for " networking"
showing 10 items of 1264 documents
A Non-WSSUS Mobile-to-Mobile Channel Model Assuming Velocity Variations of the Mobile Stations
2017
This paper aims to characterize the effects that the velocity variations of the mobile stations (MSs) produce on the correlation properties of non-stationary time-frequency (TF) dispersive mobile- to-mobile (M2M) fading channels. Toward that end, we propose a novel geometrical model for non-wide-sense stationary uncorrelated scattering (non-WSSUS) M2M channels that incorporates such variations following a plane wave propagation approach. Capitalizing on the mathematical simplicity of this approach, we derive a general expression for the four-dimensional (4D) TF correlation function (TFCF) of the proposed channel model. From this expression, we analyze the influence of the MSs' acceleration#…
The Potsdam Open Source Radio Interferometry Tool (PORT)
2021
The Potsdam Open Source Radio Interferometry Tool (PORT) is the very long baseline interferometry (VLBI) analysis software developed and maintained at the GFZ German Research Centre for Geosciences. Chiefly, PORT is tasked with the timely processing of VLBI sessions and post-processing activities supporting the generation of celestial and terrestrial reference frames. In addition, it serves as a framework for research and development within the GFZ's VLBI working group and is part of the tool set employed in educating young researchers. Starting out from VLBI group delays, PORT estimates station and radio sources positions, as well as Earth orientation parameters, tropospheric parameters, a…
Security, QoS and self-management within an end-to-end Cloud Computing environment
2015
Today, Cloud Networking is one of the recent research areas within the Cloud Computing research communities. The main challenges of Cloud Networking concern Quality of Service (QoS) and security guarantee as well as its management in conformance with a corresponding Service Level Agreement (SLA). In this thesis, we propose a framework for resource allocation according to an end-to-end SLA established between a Cloud Service User (CSU) and several Cloud Service Providers (CSPs) within a Cloud Networking environment (Inter-Cloud Broker and Federation architectures). We focus on NaaS and IaaS Cloud services. Then, we propose the self-establishing of several kinds of SLAs and the self-managemen…
Imagen técnica multi-banda en la investigación del proceso de ejecución de las pinturas. El caso del retrato de Carlos IV, de Francisco de Goya
2018
La imagen técnica multi-banda (MBTI) es ampliamente utilizada como un método eficaz para el examen de obras de arte. Aunque las diversas técnicas que lo conforman tienen una entidad propia, cuando se usan juntas proporcionan mucha más información al confrontar los diversos resultados. El objetivo principal de este trabajo es mostrar su uso en comprensión material, procedimental y creativa de un retrato del Rey Carlos IV. Más específicamente, la imagen técnica multi-banda se ha utilizado aquí para ayudar en la reconstrucción del proceso pictórico, al revelar datos relacionados con la creación y ejecución del cuadro (ductus y pinceladas, alteraciones, dibujo subyacente y primer manchado, comp…
The Technical Language in the Practice of the Students Learning the French Language
2012
Abstract The technical language is a basic element in the practice of the students in the modern organizations. At present moment the situation of the technical language acquired by the students is rather uncertain, because in universities there is the tendency to teach the classical French language, based on literary texts. In this context, they are only few teachers having a cognitive and lexical knowledge which includes the technical specialized language.The objectives of our study dedicate themselves to the discovery of new strategies and didactic methods in order to make easier the study and the education of the technical vocabulary. We worked with a group of 87 students of French lang…
Optimal configuration for size-based burst assembly algorithms at the edge node for video traffic transmissions over OBS networks
2008
Optical burst switching (OBS) has been proposed to be a technology for implementing the next generation optical Internet. In this architecture, burst assembly algorithms have an important influence in the pattern traffic that characteristic this sort of optical networks. On the other hand, traffic coming from new applications (such as video on demand, Voice over IP, online gaming or Grid computing) that have real time and bandwidth constraints, has been experimented a rapid increment. Consequently, we consider important to evaluate the performance of traffic from real time applications over OBS networks. In this paper, we evaluate the effects of implementing a size-based burst assembly sche…
Effect and optimization of burst assembly algorithms for video traffic transmissions over OBS networks
2008
Optical burst switching (OBS) has been proposed to be a technology for implementing the next generation optical Internet. In this architecture, burst assembly algorithms have an important influence in the traffic pattern that characterizes this sort of optical networks. On the other hand, traffic coming from new applications (such as video on demand, Voice over IP, online gaming or Grid services) that have real time and bandwidth constraints has been experimented a rapid increment. Consequently, we consider important to evaluate the performance of the real time traffic over OBS networks. In this paper, we evaluate the video transmissions performance (MPEG4/RTP/UDP) over OBS networks, for bo…
One size hardly fits all
2013
This paper casts recent accomplishments in the field of Wireless MAC programmability into the emerging Software Defined Networking perspective. We argue that an abstract (but formal) description of the MAC protocol logic in terms of extensible finite state machines appears a convenient and viable data-plane programming compromise for modeling and deploying realistic MAC protocol logics. Our approach is shown to comply with existing control frameworks, and entails the ability to dynamically change the MAC protocol operation based on context and scenario conditions; in essence, move from the traditional idea of "one-size-fits-all" MAC protocol stack to the innovative paradigm of opportunistic…
MAClets: Active MAC Protocols over hard-coded devices
2012
We introduce MAClets, software programs uploaded and executed on-demand over wireless cards, and devised to change the card's real-time medium access control operation. MAClets permit seamless reconfiguration of the MAC stack, so as to adapt it to mutated context and spectrum conditions and perform tailored performance optimizations hardly accountable by an once-for-all protocol stack design. Following traditional active networking principles, MAClets can be directly conveyed within data packets and executed on hard-coded devices acting as virtual MAC machines. Indeed, rather than executing a pre-defined protocol, we envision a new architecture for wireless cards based on a protocol interpr…
HTTP-level e-commerce data based on server access logs for an online store
2020
Abstract Web server logs have been extensively used as a source of data on the characteristics of Web traffic and users’ navigational patterns. In particular, Web bot detection and online purchase prediction using methods from artificial intelligence (AI) are currently key areas of research. However, in reality, it is hard to obtain logs from actual online stores and there is no common dataset that can be used across different studies. Moreover, there is a lack of studies exploring Web traffic over a longer period of time, due to the unavailability of long-term data from server logs. The need to develop reliable models of Web traffic, Web user navigation, and e-customer behaviour calls for …