Search results for "Networking & Telecommunications"
showing 10 items of 962 documents
A two-layer security model for accessing multimedia content in social networks
2016
La seguridad de un sitio web es hoy en día una de las principales preocupaciones de los administradores de sistemas. La seguridad es también el reto más importante al que se enfrentan los desarrolladores web a la hora de diseñar una plataforma fiable que ofrezca servicios a los usuarios públicos. Es bien sabido que el contenido multimedia en la web está en continuo crecimiento y, recientemente, este tipo de medios se utiliza cada vez más en las redes sociales. El acceso a los contenidos multimedia en el contexto de las redes sociales debe ser fácil y seguro. En este artículo se presenta un modelo de seguridad con capacidad semántica para el acceso a contenidos multimedia en las redes social…
A Multilevel Analysis of Economic Literacy Among International Students
2021
International student mobility has increased in the past years. The inclusion of a highly heterogeneous group of students requires updated recruitment and admission strategies. A particularly vulnerable group of international students are refugees, who have an exceptionally high risk of dropping out of their studies. We present an entrance assessment of incoming international students from 77 countries who are at the beginning of their studies in Germany. Based on this unique sample, we examine (i) whether there are systematic country-specific effects on the economic literacy of beginning students of business and economics and (ii) whether refugee students differ from the group of internati…
Traffic induced air pollution modeling: Scenario analysis for air quality management in street canyon
2019
This study was supported by the Riga City research project DMV-17-60-lī-03.02.2017. The authors wish to thank the Riga City Council and Latvian Environment, Geology and Meteorology Centre for data used in this study.
Statistical atmospheric parameter retrieval largely benefits from spatial-spectral image compression
2021
The infrared atmospheric sounding interferometer (IASI) is flying on board of the Metop satellite series, which is part of the EUMETSAT Polar System. Products obtained from IASI data represent a significant improvement in the accuracy and quality of the measurements used for meteorological models. Notably, the IASI collects rich spectral information to derive temperature and moisture profiles, among other relevant trace gases, essential for atmospheric forecasts and for the understanding of weather. Here, we investigate the impact of near-lossless and lossy compression on IASI L1C data when statistical retrieval algorithms are later applied. We search for those compression ratios that yield…
Self-Localization of Distributed Microphone Arrays Using Directional Statistics with DoA Estimation Reliability
2019
This paper addresses the problem of self-localization of distributed microphone arrays from microphone recordings by following a two-step optimization procedure. In the first step, the relative geometry of the sources and arrays is inferred by the proposed maximum likelihood estimator. It is derived under the assumption that the acquired unit-norm vectors pointing towards the unknown source positions follow a von Mises-Fisher distribution in a D-dimensional space. In the second step, the absolute positions and synchronization offsets between the arrays are estimated from the inferred relative geometry by using the Least Squares procedure. To improve the accuracy of the method, we propose as…
NFVMon: Enabling Multioperator Flow Monitoring in 5G Mobile Edge Computing
2018
With the advances of new-generation wireless and mobile communication systems such as the fifth-generation (5G) mobile networks and Internet of Things (IoT) networks, demanding applications such as Ultra-High-Definition video applications is becoming ever popular. These applications require real-time monitoring and processing to meet the mission-critical quality of service requirements and are expected to be supported by the emerging fog or edge computing paradigms. This paper presents NFVMon, a novel monitoring architecture to enable flow monitoring capabilities of network traffic in a 5G multioperator mobile edge computing environment. The proposed NFVMon is integrated with the management…
MCMIPv6: Multicast Configuration-based Mobile IPv6 protocol
2010
International audience; Mobile IPv6 (MIPv6) and its basic extension for network mobility NEMO were initially designed to manage the mobility of device users and networks respectively while maintaining a permanent IP address. Nevertheless, the different MIPv6's experiments have shown many lacks in case of high mobility of nodes such as in vehicular networks. To overcome these lacks, many solutions have been proposed by the research community. The most famous ones are HMIPv6 and FMIPv6 tackling each a specific issue. On the one hand, FMIPv6 introduces a solution to effectively minimize the L2/L3 latency and avoid the packets losses during the handover procedure. On the other hand, HMIPv6 is e…
Network Connectivity and Area Coverage for UAV Fleet Mobility Model with Energy Constraint
2016
International audience; Our main focus through the present paper is on developing an original distributed mobility model for autonomous fleet of interconnected UAVs (Unmanned Aerial Vehicles) performing an area exploration mission. The UAVs, equipped with wireless ad-hoc capabilities, are required to optimally explore an area while maintaining connectivity with their neighboring UAVs and the base station. Because energy is a scarce resource, especially for UAVs, its wise management is quite beneficial for the network lifetime and mission success. Hence, the proposed mobility model, compared to other models in the literature, is the first to ever include the remaining energy level as decisio…
Formal Analysis and Model Checking of a Group Authentication Protocol by Scyther
2016
Scyther [1] is designed to check the security and vulnerabilities of security protocols. In this paper, we use Scyther to analyze two discrete logarithm problem (DLP) based group authentication protocols proposed in [2]. These two protocols are claimed to satisfy several security requirements, but only part of them have been checked because of the properties and limitations of Scyther. Some positive results have been gained and show that the protocols provide mutual authentication and implicit key authentication and are secure against impersonation attack. An important innovation in this paper is that we have extended the expressing ability of Scyther by giving some reasonable assumption du…
Towards a Formal Analysis of MQtt Protocol in the Context of Communicating Vehicles
2017
International audience; The paper presents a formal approach to model, analyze, and verify a variant of Message Queue Telemetry Transport protocol (MQtt), dedicated to communicating vehicles (MQtt-CV) that send collected data to automotive infrastructures(subscribers). Our formal approach is based on Promela language and its system verification tool, the model checker SPIN. We propose a slight modification of MQtt protocol to reduce the big volume of data collected and sent by vehicles to infrastructures. Indeed, in the original version of MQtt protocol, when a broker receives data from publishers, it sends them directly to its subscribers without any filtration. As consequence, subscribers…