Search results for " Network"
showing 10 items of 6428 documents
Enabling Backoff and Eliminating Redundant Idle Period for Medium Access in LTE-U
2017
To address the burgeoning demand for mobile data, 3GPP is actively studying the capability of operating LTE in the unlicensed band, referred to as LTE-U. One of the main challenges of this approach is to maintain better coexistence between WiFi and LTE-U devices. To enable the coexistence, the listen before talk (LBT) principle has been adopted for LTE-U medium access with two flavors of mechanisms, i.e., load based equipment (LBE) and frame based equipment (FBE) access. In this paper, we consider the FBE mechanism and enhance its performance by introducing a backoff procedure for LTE devices. We investigate the original FBE mechanism defined by 3GPP and the enhanced FBE (E- FBE) mechanism fr…
Preamble Sampling MAC Protocol for Low Power Wireless Sensor Networks with IEEE 802.15.4 Transceivers
2006
In this paper a preamble sampling MAC protocol for low power wireless sensor networks is proposed. The article describes the implementation of the protocol using network nodes equipped with the Chipcon CC2420 802.15.4 transceiver. The power consumption of the transceiver has been measured and the MAC protocol has been adapted to the transceiver properties. The results show the trade-off between power consumption and transmission delay for this algorithm during the communication process.
Genomic Analysis of Bacterial Outbreaks
2016
The study of outbreaks of infectious diseases has been revolutionized by the current availability of fast and efficient, high-throughput methods capable of yielding the nucleotide sequence of complete genomes of viruses and bacteria within a few days, or even hours. These methods are replacing previous molecular techniques which have been used for the past 30 years, although many of them are still the usual approach for many such investigations. Here we review the major technologies currently in use for high-throughput sequencing of bacterial genomes emphasizing their advantages and drawbacks for the analysis of outbreaks. The use of more efficient methods does not necessarily mean that all…
Non-regular network performance comparison between HSDPA and LTE
2010
In this paper we study and benchmark the performance of 3rd Generation Partnership Project (3GPP) High Speed Downlink Packet Access (HSDPA) and 3GPP Long Term Evolution (LTE) Downlink with constant bit rate type traffic. In addition a non-regular simulation scenario is considered using realistic propagation data and base station positions related to Tokyo city downtown area. HSDPA was introduced in 3GPP Release 5 and in further releases the technology has been improved with e.g. receive and transmit diversity technologies and support for higher order modulation schemes. LTE was introduced in 3GPP Release 8 with completely new physical layer and improved Radio Resource Management (RRM) funct…
Transnational Social Network Analysis
2012
AbstractThe following article discusses methods of social network analysis (SNA) as an approach in researching transnational social formations. SNA allows transnationality to be studied through relationships between actors, enabling the investigation of social structures which expand nation-state frameworks. Two empirical examples are used to address the central characteristics of the network analysis approach (focus on relations, systematic collection of data, means of visualising network data) and their relevance for research on cross-border social phenomena. The article also investigates the significance of geographical mobility in the research process, culminating in reflection on how “…
Strategies for Making Life
2014
Synthetic biology is a multifaceted discipline and the pathways towards an artificial cell are diverse. Top-down strategies seek simplification of genomes, their chemical synthesis and transplantation into a cell chassis. In the long term, scientists hope to have genomic platforms to reinvent metabolic networks capable of producing molecules of biotechnological interest. On the other hand, a bottom-up strategy relies on the chemical implementation of fundamental concepts such as self-reproduction, self-replication and self-maintaining systems. In addition to the artificial synthesis of simplified genomes and protocells, some scientists explore xenobiology, or making life as we do not know i…
Data Mining Approach for Detection of DDoS Attacks Utilizing SSL/TLS Protocol
2015
Denial of Service attacks remain one of the most serious threats to the Internet nowadays. In this study, we propose an algorithm for detection of Denial of Service attacks that utilize SSL/TLS protocol. These protocols encrypt the data of network connections on the application layer which makes it impossible to detect attackers activity based on the analysis of packet payload. For this reason, we concentrate on statistics that can be extracted from packet headers. Based on these statistics, we build a model of normal user behavior by using several data mining algorithms. Once the model has been built, it is used to detect DoS attacks. The proposed framework is tested on the data obtained w…
In the rail sector, France needs to do more to connect its regional networks to the European network
2023
In an article for "Le Monde" newspaper, the legal expert Martial Pernet notes that, despite the texts in force, which he urges to be applied, efforts must be made to achieve the unification of the European rail network.
From the Rhin-Rhône TGV to Rhin-Rhône "territory" : reticularity, mobility and territoriality in an intermediary space
2013
High-speed rail, destined to reduce the times-distances between major French and European cities, tends to push intermediary spaces into a rather unfavorable situation. Strongly polarized by the large urban centers that surround them, these intermediary areas are usually reduced to their sole status of transit areas. However, the Eastern tract, the first section of the LGV Rhine-Rhône project, through its regional dimension, constitutes a factor in the emergence of a territorialization process of the Rhine-Rhone area. Thus, the arrival of high speed rail is responsible for the creation of a network of cities that extends from Dijon to Basel. To address this territorial issue, a detailed ana…
Du TGV Rhin-Rhône au "Territoire" Rhin-Rhône : réticularité, mobilité et territorialité dans un espace intermédiaire
2013
High-speed rail, destined to reduce the times-distances between major French and European cities, tends to push intermediary spaces into a rather unfavorable situation. Strongly polarized by the large urban centers that surround them, these intermediary areas are usually reduced to their sole status of transit areas. However, the Eastern tract, the first section of the LGV Rhine-Rhône project, through its regional dimension, constitutes a factor in the emergence of a territorialization process of the Rhine-Rhone area. Thus, the arrival of high speed rail is responsible for the creation of a network of cities that extends from Dijon to Basel.To address this territorial issue, a detailed anal…