Search results for "Static"
showing 10 items of 1528 documents
Accurate reliability and availability models for direct interconnection networks
2001
Fault tolerance in multicomputer interconnection networks has been traditionally studied by determining the worst possible combination of faulty components that causes its failure and then assuming that this will occur. But, the probability of the worst possible combination is usually low, and the routing algorithm may be able to find a route between source and destination nodes. The network dependability parameters computed according to this approach will be underestimated. In this paper we propose a methodology for accurately evaluating interconnection network dependability. In addition, we apply it to obtain an accurate estimation of the reliability and availability parameters in a 2-D m…
QoS Based Routing Protocol for Intra-Mesh Infrastructure Communications
2015
International audience; Mesh Networks (WMNs) have been considered as a promising alternative to conventional wired networks, thanks to its flexibility and easy deployment. Thus, to ensure a satisfying level of QoS guarantees for real-time and streaming applications such as Voice over IP (VoIP) and Video on Demand (VoD), we propose a novel QoS based routing protocol for wireless mesh environments, called Hybrid QoS Mesh Routing (HQMR), jointly with a clustering algorithm to enhance scalability issues within the mesh infrastructure. HQMR is composed of two routing sub-protocols: a reactive routing sub-protocol for intra-infrastructure communications and a proactive QoS based multi-tree routin…
Self-configuring multipath intra-mesh infrastructure QoS based routing
2016
International audience; Multi-path routing concept was largely exploited in wireless networks to provide benefits such as fault tolerance, load balancing, performance improvement in terms of latency, etc. In this paper, we propose a multi-path routing based protocol named MP-IMRR (Multi-path Intra-Mesh infrastructure Routing protocol) to improve our previously defined QoS based routing protocol for wireless mesh networks (i.e. IMRR). MP-IMRR is defined in order to achieve better reactivity and faster recovery from eventual route failures than the IMRR protocol by adopting the backup routes concept. Besides, given the complexity increase while considering network management systems, we adopt…
Cooperative layer-2 based routing approach for hybrid wireless mesh networks
2013
In a Wireless Mesh Network (WMN), the convenience of a routing strategy strongly depends on the mobility of the intermediate nodes that compose the paths. Taking this behaviour into account, this paper presents a routing scheme that works differently accordingly to the node mobility. In this sense, a proactive routing scheme is restricted to the backbone to promote the use of stable routes. Conversely, the reactive protocol is used for searching routes to or from a mobile destination. Both approaches are simultaneously implemented in the mesh nodes so that the routing protocols share routing information that optimises the network performance. Aimed at guaranteeing the IP compatibility, the …
A secure intersection-based routing protocol for data collection in urban vehicular networks
2014
Data routing has gained great intention since the appearance of Vehicular Networks (VANETs). However, in the presence of attackers, reliable and trustworthy operations in such networks become impossible without securing routing protocols. In this paper, we target to study and design a secure routing protocol S-GyTAR for vehicular environments. Several kinds of routing techniques are proposed in the literature and could be classified into topology-based or position-based strategies. Position-based is the most investigated strategy in vehicular networks due to the unique characteristics of such networks. For this reason, this work is based on the well-known intersection-based routing protocol…
IMRR and IMPR Routing Protocols For Inter and Intra Wireless Mesh Communications
2015
Given the evolution of wireless technologies, Wireless Mesh Networks (WMN) have appeared as an emerging low-cost solution to ensure last-mile connectivity to the Internet network. However, providing real-time and streaming applications, such as VoIP (Voice over IP) and VoD (Video on Demand), with a satisfying QoS level is considered as an important challenge within these networks. In this paper, we propose a QoS based routing protocol, called Hybrid QoS Mesh Routing (HQMR), jointly with a clustering algorithm to improve the scalability of mesh networks. HQMR is composed of two routing sub- protocols: a reactive QoS based routing protocol for intra-mesh infrastructure communications and a pr…
SUBOPTIMAL-OPTIMAL ROUTING FOR LAN INTERNETWORKING USING TRANSPARENT BRIDGES
1998
The current standard transparent bridge protocol IEEE-802.1D is based on the Spanning Tree (ST) algorithm. It has a very important restriction: it cannot work when the topology has active loops. Therefore, a tree is the only possible interconnection topology that can be used. The ST algorithm guarantees that the active topology is a tree discarding lines that form loops. However, because of this, network bandwidth cannot be fully utilized. Moreover, trees have a very serious bottleneck near the root. This paper proposes a new transparent bridge protocol for LAN interconnection that allows active loops. Therefore, strongly connected regular topologies like tori, hypercubes, meshes, etc., as…
Catalysis in glycine N-methyltransferase: testing the electrostatic stabilization and compression hypothesis.
2006
Glycine N-methyltransferase (GNMT) is an S-adenosyl-l-methionine dependent enzyme that catalyzes glycine transformation to sarcosine. Here, we present a hybrid quantum mechanics/molecular mechanics (QM/MM) computational study of the reaction compared to the counterpart process in water. The process takes place through an SN2 mechanism in both media with a transition state in which the transferring methyl group is placed in between the donor (SAM) and the acceptor (the amine group of glycine). Comparative analysis of structural, electrostatic, and electronic characteristics of the in-solution and enzymatic transition states allows us to get a deeper insight into the origins of the enzyme's c…
S. Typhimurium virulence changes caused by exposure to different non-thermal preservation treatments using C. elegans
2017
The aims of this research study were: (i) to postulate Caenorhabditis elegans (C. elegans) as a useful organism to describe infection by Salmonella enterica serovar Typhimurium (S. Typhimurium), and (ii) to evaluate changes in virulence of S. Typhimurium when subjected repetitively to different antimicrobial treatments. Specifically, cauliflower by-product infusion, High Hydrostatic Pressure (HHP), and Pulsed Electric Fields (PEF). This study was carried out by feeding C. elegans with different microbial populations: E. coli OP50 (optimal conditions), untreated S. Typhimurium, S. Typhimurium treated once and three times with cauliflower by-product infusion, S. Typhimurium treated once and f…
Lack of mutagenic and co-mutagenic effects of magnetic fields during magnetic resonance imaging
2001
Mutagenic and co-mutagenic effects of static, pulsed bipolar gradient, and high-frequency magnetic fields, as well as combinations of them, were examined using the Ames test. The Ames test using Salmonella typhimurium bacteria, wild-type strain RTA, preincubation assay, without metabolic activation, was performed. All combinations of magnetic fields were tested with and without co-exposure to N-methyl-N′-nitro-N-nitrosoguanidine and benzo[a]pyrene-4,5-oxide, ethylene oxide, carboplatin, or cisplatin. As expected, chemical mutagens caused a clear-cut increase of the revertants in the Ames test. However, neither the static fields nor a combination of a static magnetic field with the time-vary…