Search results for "Computer network"

An Optimized Roadside Units (RSU) Placement for Delay-Sensitive Applications in Vehicular Networks

2015

International audience; Over the last few years, a lot of applications have been developed for Vehicular Ad Hoc NETworks (VANETs) to exchange information between vehicles. However, VANET is basically a Delay Tolerant Network (DTN) characterized by intermittent connectivity, long delays and message losses especially in low density regions [1]. Thus, VANET requires the use of an infrastructure such as Roadside Units (RSUs) that permits to enhance the network connectivity. Nevertheless, due to their deployment cost, RSUs need to be optimally deployed. Hence, the main objective of this work is to provide an optimized RSUs placement for delay-sensitive applications in vehicular networks that imp…

Geographical Routing for Delay Tolerant Encounter Networks

2007

Delay Tolerant Networks (DTNs) are intermittently connected networks, where direct end--to--end path between communicating nodes may never exist. To achieve eventual delivery some nodes must store messages and wait opportunity to forward them. In mobile environment, one of the most challenging problems for routing protocols is to decide, which nodes should store the message to achieve eventual delivery as quick as possible. Common approach is to propagate message into large group of nodes, hoping one of them will reach the destination. These solutions, however, are not very scalable as they generate plenty of extra load and traffic to network. Further more, message carriers have no means to…

Perceptions and behaviour of cruise tourists during their visit to a port of call

2019

[EN] The purpose of the present research is to assess the perceptions of authenticity and crowding of cruise tourists visiting a port of call and its influence on their future behavioural intentions. The research was carried out in the city of Valencia, because it is one of the main Spanish cruise ports and is a representative city of the Mediterranean ports of call for the cruise business. A total of 467 valid interviews were obtained. For the analysis of data, the Statistical Package for the Social Sciences (SPSS version 22.0) was used. The findings reveal that Valencia is perceived as an authentic destination with moderate levels of human and spatial crowding. The analysis also demonstra…

Toward a Theory of Information Systems Security Behaviors of Organizational Employees: A Dialectical Process Perspective

2019

Practice-/policy-oriented abstract: Understanding why employees do or do not comply with information systems security (ISS) procedures is an imperative in today’s organizations whose futures often depend on how well they protect and harness information assets. We use a predominantly inductive approach to develop a theoretical understanding of how employees’ reasons for engaging to ISS behaviors (ISSBs) change over time, using ideas from dialectics as our scaffolding. Our dialectical view of this process suggests that explanations for engaging in different ISSBs change over time as individuals seek to balance contradictory demands. Furthermore, our view suggests that new experiences and ext…

Per-flow signalling extension across DiffServ domains

2003

This paper describes a framework devised to extend per-flow admission control operation across Differentiated Services domains. Although the specific case of interoperability with RSVP is under discussion, our proposal can be easily adapted to other hop-by-hop signalling protocols. In our framework, DiffSery border routers accomplish three tasks. First, during the set-up phase, flows are mapped onto PHB groups on the basis of their QoS and traffic specifications. Second, signalling packets are tunnelled into IP packets marked as “probes”, where the “probe” marking is a DCSP value associated to the considered PHB Group. Third, when the flow set-up is complete, flow data packets are marked as…

A Branch-Price-and-Cut Algorithm for the Min-Max k -Vehicle Windy Rural Postman Problem

2013

[EN] The min-max k -vehicles windy rural postman problem consists of minimizing the maximal distance traveled by a vehicle to find a set of balanced routes that jointly service all the required edges in a windy graph. This is a very difficult problem, for which a branch-and-cut algorithm has already been proposed, providing good results when the number of vehicles is small. In this article, we present a branch-price-and-cut method capable of obtaining optimal solutions for this problem when the number of vehicles is larger for the same set of required edges. Extensive computational results on instances from the literature are presented.

2021

Abstract The use of the internet and social media have changed consumer behavior and the ways in which companies conduct their business. Social and digital marketing offers significant opportunities to organizations through lower costs, improved brand awareness and increased sales. However, significant challenges exist from negative electronic word-of-mouth as well as intrusive and irritating online brand presence. This article brings together the collective insight from several leading experts on issues relating to digital and social media marketing. The experts’ perspectives offer a detailed narrative on key aspects of this important topic as well as perspectives on more specific issues i…

NP-completeness of the hamming salesman problem

1985

It is shown that the traveling salesman problem, where cities are bit strings with Hamming distances, is NP-complete.

First-order expressibility of languages with neutral letters or: The Crane Beach conjecture

2005

A language L over an alphabet A is said to have a neutral letter if there is a letter [email protected]?A such that inserting or deleting e's from any word in A^* does not change its membership or non-membership in L. The presence of a neutral letter affects the definability of a language in first-order logic. It was conjectured that it renders all numerical predicates apart from the order predicate useless, i.e., that if a language L with a neutral letter is not definable in first-order logic with linear order, then it is not definable in first-order logic with any set N of numerical predicates. Named after the location of its first, flawed, proof this conjecture is called the Crane Beach …

Balls into non-uniform bins

2014

Balls-into-bins games for uniform bins are widely used to model randomized load balancing strategies. Recently, balls-into-bins games have been analysed under the assumption that the selection probabilities for bins are not uniformly distributed. These new models are motivated by properties of many peer-to-peer (P2P) networks, which are not able to perfectly balance the load over the bins. While previous evaluations try to find strategies for uniform bins under non-uniform bin selection probabilities, this paper investigates heterogeneous bins, where the "capacities" of the bins might differ significantly. We show that heterogeneous environments can even help to distribute the load more eve…