Search results for "extension"
showing 10 items of 534 documents
QoS Support for Time-Constrained Multimedia Communications in IEEE 802.11 WLANs: A Performance Evaluation
2005
During the past few years, we have been witnessing the massive deployment of IEEE 802.11 wireless LANs. Even though the widespread deployment of such wireless LANs, many studies are still underway aiming to design and develop simple yet effective QoS mechanisms for supporting time-constrained services over such platforms. In this paper, we first overview five different QoS mechanisms recently introduced in the literature as well as the upcoming IEEE 802.11e (EDCA) standard. We then carry out a comparative performance evaluation of all the QoS mechanisms. We focus our study on the effectiveness of the various QoS mechanisms for supporting time-constrained services.
QoS Mechanisms for IEEE 802.11 Wireless LANs
2004
Currently the Internet provides users with access to information across the world using IP technology. Until now most access points to the Internet have been fixed stations at given locations, but with increasing sales of mobile devices, mobility has become a major trend. Therefore, the Internet is becoming more and more heterogeneous due to the recent explosion of wireless networks. The IEEE 802.11 wireless LAN (WLAN) is the most widely used WLAN standard nowadays. Currently the IEEE 802.11 standard specifies an over-the-air interface between wireless devices. However, QoS services over this technology are still being defined aiming to provide support to multiple applications. Thus, a larg…
Extranodal extension of nodal metastasis is the main prognostic moderator in squamous cell carcinoma of the esophagus after neoadjuvant chemoradiothe…
2017
Several studies, including comprehensive systematic reviews with meta-analyses of our group of research, have demonstrated the negative prognostic impact of the extranodal extension of nodal metastasis (ENE) in different cancer types, including squamous cell carcinoma (SCC) of the vulva, of the penis and of head and neck, as well as in tumors of the digestive and genitourinary systems, in thyroid cancer and others (1-17).
The nearly Gorenstein property for numerical duplications and semitrivial extensions
2022
In this thesis we present and study the ideal duplication, a new construction within the class of the relative ideals of a numerical semigroup $S$, that, under specific assumptions, produces a relative ideal of the numerical duplication $SJoin^b E$, for some ideal $E$ of $S$. We prove that every relative ideal of the numerical duplication can be uniquely written as the ideal duplication of two relative ideals of $S$; this allows us to better understand how the basic operations of the class of the relative ideals of $SJoin^b E$ work. In particular, we characterize the ideals $E$ such that $SJoin^b E$ is nearly Gorenstein. With the aim to generalize this construction to commutative rings with…
Polysemy and gestaltist computation. some notes on gestaltist compositionality
2019
The paper is devoted to the concept of Gestaltist Compositionality. It is divided into two parts. The first part will introduce a minimal definition of «Gestaltist Compositionality». Moreover, it will prove that the computations implemented by this model of compositionality are sufficiently flexible to ensure the presence of several orders of semantic determination. The second part will be devoted to an investigation of the consequences of this result with particular reference to the identification of some versions of compositionality which relax the condition of semantic atomism without weakening the links of determination between understanding of the compounds and understanding of the com…
Evidence for a novel cytoplasmic processing event in ribosome maturation in the sea urchin Paracentrotus lividus
2010
In this work, we demonstrate the existence of a cytoplasmic processing step, never before described, involving both the pre-ribosomal subunits in the sea urchin Paracentrotus lividus. Northern-blot hybridization, primer extension, S1 mapping experiments and in situ hybridizations allowed us to demonstrate that cytoplasmic processed particles are successively re-imported into the nucleus, where maturation of their RNAs is completed prior to being exported to the cytoplasm. Our findings lead to the proposal of a new model of ribosome maturation and shuttling. Moreover, preliminary data from our laboratory suggest that the maturation pathway we propose in P. lividus may not be unique to the se…
A common extension of Arhangel'skii's Theorem and the Hajnal-Juhasz inequality
2019
AbstractWe present a result about $G_{\unicode[STIX]{x1D6FF}}$ covers of a Hausdorff space that implies various known cardinal inequalities, including the following two fundamental results in the theory of cardinal invariants in topology: $|X|\leqslant 2^{L(X)\unicode[STIX]{x1D712}(X)}$ (Arhangel’skiĭ) and $|X|\leqslant 2^{c(X)\unicode[STIX]{x1D712}(X)}$ (Hajnal–Juhász). This solves a question that goes back to Bell, Ginsburg and Woods’s 1978 paper (M. Bell, J.N. Ginsburg and R.G. Woods, Cardinal inequalities for topological spaces involving the weak Lindelöf number, Pacific J. Math. 79(1978), 37–45) and is mentioned in Hodel’s survey on Arhangel’skiĭ’s Theorem (R. Hodel, Arhangel’skii’s so…
Group Extensions and Graphs
2016
A classical result of Gaschütz affirms that given a finite A-generated group G and a prime p, there exists a group G# and an epimorphism phi: G# ---> G whose kernel is an elementary abelian p-group which is universal among all groups satisfying this property. This Gaschütz universal extension has also been described in the mathematical literature with the help of the Cayley graph. We give an elementary and self-contained proof of the fact that this description corresponds to the Gaschütz universal extension. Our proof depends on another elementary proof of the Nielsen-Schreier theorem, which states that a subgroup of a free group is free.
An Extended Data Object-driven Approach to Data Quality Evaluation: Contextual Data Quality Analysis
2019
This research is an extension of a data object-driven approach to data quality evaluation allowing to analyse data object quality in scope of multiple data objects. Previously presented approach was used to analyse one particular data object, mainly focusing on syntactic analysis. It means that the primary data object quality can be analysed against secondary data objects of unlimited number. This opportunity allows making more comprehensive, in-depth contextual data object analysis. The given analysis was applied to open data sets, making comparison between previously obtained results and results of application of the extended approach, underlying importance and benefits of the given exten…
Non-oxidative dehydroaromatization of methane:an effective reaction regeneration cyclic operation for catalyst life extension
2015
[EN] Non-oxidative methane aromatization is an attractive direct route for producing higher hydrocarbons. It is highly selective to benzene despite the low conversion due to thermodynamic limitations, and Mo/H-ZSM-5, the first catalyst proposed for this reaction, is still considered as one of the most adequate. The major problem of this process is the severe catalyst deactivation due to the rapid build-up of carbonaceous deposits on the catalysts. Here we present an effective regeneration procedure that extends the life of Mo/zeolite based catalysts by combining reaction periods of 1.5 h with 0.5 h regeneration steps in a continuous cyclic mode and methane activation after each regeneration…