Previous work on the coverage of mobile sensor networks focuses algorithms to reposition sensors in order achieve a static configuration with an enlarged covered area. In this paper, we study dynamic aspects network that depend process movement. As time goes by, position is more likely be covered; targets might never detected stationary can now by moving sensors. We characterize area at specific instants and during intervals, as well it takes detect randomly located target. Our results show...

A number of mobility models have been proposed for the purpose either analyzing or simulating movement users in a mobile wireless network. Two more popular are random waypoint and direction models. The model is physically appealing but difficult to understand. Although less physically, it much easier User speeds easily calculated, unlike model, and, as we observe, user positions directions uniformly distributed. contribution this paper establish last property rich class that allow future...

The Transmission Control Protocol (TCP) was designed to provide reliable end-to-end delivery of data over unreliable networks.In practice, most TCP deployments have been carefully in the context wired networks.Ignoring properties wireless ad hoc networks can lead implementations with poor performance.In order adapt environment, improvements proposed literature help differentiate between different types losses.Indeed, mobile or static losses are not always due network congestion, as it is...

The Differentiated services (diffserv) architecture has been proposed as a scalable solution for providing service differentiation among flows without any per-flow buffer management inside the core of network. It advocated that it is feasible to provide set by choosing an appropriate "marking profile" each flow. In this paper, we examine (i) whether possible TCP marking profiles flow, (ii) under what circumstances, are able influence flow receives, and, (iii) how choose correct profile...

A generic stochastic model with only two input parameters is introduced to evaluate the message delay in mobile ad hoc networks (MANETs) where nodes may relay messages. The Laplace-Stieltjes transform (LST) of obtained for protocols: two-hop and unrestricted multicopy protocol. From these results we deduce expected delays. It shown that, despite its simplicity, accurately predicts under both strategies a number mobility models (the random waypoint, direction walker models).

We study a quantum entanglement switch that serves k users in star topology. model variants of the system using continuous-time Markov chains (CTMCs) and obtain expressions for capacity expected number qubits stored memory at switch. Using CTMCs allows us to analytic results systems which links are homogeneous or heterogeneous switches have infinite finite buffer sizes. In addition, we can easily effects decoherence states this technique. From numerical observations, discover has little...

Considered is a mobile ad hoc network consisting of three types nodes (source, destination and relay nodes) using the two-hop routing protocol. Packets at are assumed to have limited lifetime in network. All moving inside bounded region according some random mobility model. Both closed-form expressions, asymptotic results when number large, provided for packet delivery delay energy needed transmit from source its destination. We also introduce evaluate variant protocol that limits generated...

We consider a discrete-time queueing system consisting of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K + 1</tex> classes customers competing for single server at an infinite capacity queue. For each customer class the arrival sequence forms renewal but is otherwise arbitrary. The service requirements are geometric with class-dependent parameter. optimization criterion to minimize linear combination average line lengths 1 through...

The modeling and analysis of an LRU cache is extremely challenging as exact results for the main performance metrics (e.g., hit rate) are either lacking or cannot be used because their high computational complexity large caches. As a result, various approximations have been proposed. state-of-the-art method so-called TTL approximation, first proposed shown to asymptotically IRM requests by Fagin [13]. It has applied other workload models numerically demonstrated accurate but without...

Peer-to-peer (P2P) systems are complex to analyze due their large number of users who connect intermittently and the frequency requests for files or Web objects. In this paper we propose a mathematical model in which request streams represented as fluid flows then apply an analysis Squirrel: recent P2P cooperative cache. Our provides low-complexity means estimate performance Squirrel (hit probability latency) exhibits key qualitative properties system. The accuracy our is validated by...

In this paper we study the asymptotic behavior of tail stationary backlog distribution in a single server queue with constant service capacity c , fed by so-called M / G /∞ input process or Cox . Asymptotic lower bounds are obtained for any and upper derived when is subexponential distribution. We find to be tight some instances, e.g. corresponds either Pareto lognormal − ρ &lt; 1, where arrival rate at buffer.

Interchange arguments are applied to establish the optimality of priority list policies in three problems. First, we prove that a multiclass tandem two ·/ M /1 queues it is always optimal second node serve according cµ rule. The result holds more generally if first replaced by network consisting with Bernoulli routing. Next, for scheduling single server feedback, simplified proof Klimov's given. From follows index rule among idling general service time distributions, and pre-emptive when...

This work focuses on a class of distributed storage systems whose content may evolve over time. Each component or node the system is mobile and set all nodes forms delay tolerant (ad hoc) network (DTN). The goal paper to study efficient ways for distributing evolving files within DTNs managing dynamically their content. We specify dynamic where not only latest version useful but also previous ones; we restrict however file has no use if another more recent available. DTN composed fixed...

In this paper we study the behavior of a continuous time random walk (CTRW) on stationary and ergodic varying dynamic graph. We establish conditions under which CTRW is process. general, distribution walker depends rate difficult to characterize. However, characterize in following cases: i) significantly larger or smaller than graph changes (time-scale separation), ii) proportional degree node that it resides (coupled dynamics), iii) degrees belonging same connected component are identical...