Search results for "WLAN"
showing 10 items of 52 documents
Materiały do poznania fauny Kampinoskiego Parku Narodowego: Apionidae i Nanophyidae (Coleoptera: Curculionoidea)
2013
New localities of 35 species of Apionidae and 2 species of Nanophyidae in the Kampinos National Park are presented, among them respectively 26 and 2 species new for the studied area. Regarding Apionidae, 8 of 9 species recorded from the Kampinos National Park in literature, were confirmed to occur there. Perapion oblongum (GYLL.) has been recorded from the Mazovian Lowland for the first time
Joint routing and per-flow fairness in wireless multihop networks
2008
In wireless multihop networks communication between two end-nodes is carried out by hopping over multiple short wireless links. Traditional CSMA/CA based media access control does not work satisfactory in a multihop scenario, since an intended target of a communication may be subject to mutual interference imposed by concurrent transmissions from nodes which cannot directly sense each other, causing unfair throughput allocation. Although TDMA seems to be a more promising solution, careful transmission scheduling is needed in order to achieve error-free communication and fairness. In our previous work, a TDMA scheduling algorithm has been proposed that schedules the transmissions in a fair m…
Learning from Errors: Detecting ZigBee Interference in WiFi Networks
2014
In this work we show how to detect ZigBee interference on commodity WiFi cards by monitoring the reception errors, such as synchronization errors, invalid header formats, too long frames, etc., caused by ZigBee transmissions. Indeed, in presence of non-WiFi modulated signals, the occurrence of these types of errors follows statistics that can be easily recognized. Moreover, the duration of the error bursts depends on the transmission interval of the interference source, while the error spacing depends on the receiver implementation. On the basis of these considerations, we propose the adoption of hidden Markov chains for characterizing the behavior of WiFi receivers in presence of controlle…
Efficiency analysis of burst transmissions with block ACK in contention-based 802.11e WLANs
2005
The channel utilization efficiency of the standard 802.11 networks is severely compromised when high data transmission rates are employed, since physical layer headers and control frames are transmitted at low rate, thus wasting more channel time, proportionally. The extensions defined in the emerging 802.11e for quality-of-service (QoS) provisioning include some new mechanisms developed in order to improve the efficiency. Those include data transmission bursting (referred to as TXOP operation) and acknowledgment aggregation (referred to as block ACK). These two features allow it to offer new data transmission services, in which the data delivery and acknowledgment unit is not a single fram…
Radio frequency fingerprinting for outdoor user equipment localization
2017
The recent advancements in cellular mobile technology and smart phone usage have opened opportunities for researchers and commercial companies to develop ubiquitous low cost localization systems. Radio frequency (RF) fingerprinting is a popular positioning technique which uses radio signal strength (RSS) values from already existing infrastructures to provide satisfactory user positioning accuracy in indoor and densely built outdoor urban areas where Global Navigation Satellite System (GNSS) signal is poor and hard to reach. However a major requirement for the RF fingerprinting to maintain good localization accuracy is the collection and updating of large training database. The Minimization…
HERPETOFAUNA DI HUTAN DATARAN RENDAH HAYA, MAMBERAMO, PAPUA
2008
<p><em>During about 19 days field work survey (7-25 February 2008) on the Haya lowland forest area, Mamberamo Papua. Eksploration is the methods used in this study. Reptiles and amphibians were collected by hand on the night and day in several type of habitat (plains, swamp, oxbowlake, stream, creeks and hills). The result showed that 48 species of herpetofauna (21 species frogs, 19 species of lizard, six species of snakes and one species of turtles and crocodile) were found.</em></p>
RF fingerprinting for user locationing in LTE/WLAN networks
2016
Location based applications and services have become popular in many wireless communication devices. This thesis study presents a performance evaluation of Radio Frequency (RF) fingerprinting framework in heterogeneous Long Term Evolution (LTE) and Wireless Local Area Networks (WLAN) using Minimization of Drive Testing (MDT) measurements which allow automated construction of extensive RF fingerprint training databases. Utilization of MDT data could create additional opportunities for service provider and application developers. Typical RF fingerprint consist of radio measurements from multiple LTE transceiver stations and WLAN access points. Regardless environmental conditions, received sig…
Parenté et organisation sociale chez les Wayùu. Retour sur la question
2021
Dans cet article, l’auteur revient sur certaines questions concernant le domaine de la parenté et de l’organisation sociale des Wayùu de la péninsule de La Guajira, dans la zone frontalière du nord de la Colombie et du Venezuela. Prenant pour point de départ le désaccord entre Goulet et Saler sur l’existence de catégories et de groupes de lignages et sur la place de ceux-ci dans le monde social des Wayùu, il opte pour le point de vue de Saler, à savoir que ces catégories peuvent être considérées non seulement dans les mythes au sujet de l’origine de la société wayùu, mais aussi dans les différents concepts qui réfèrent à l’ancestralité utérine commune d’un groupe de gens apparentés, ainsi q…