The Globus Replica Catalog is a fundamental Data Grid service. It is important to evaluate the performance of this complex system, currently based on LDAP servers. The paper presents the results obtained during performance tests, which were done with three popular LDAP implementations (OpenLDAP, Oracle Internet Directory (OID), Netscape Directory) available today. Oracle9i is a new product and ...

In Mobile Sensor Network, attacker can easily capture a node and compromise that sensor node and extract keying materials from that compromised node and make replicas of them. These replica node attacks are dangerous because they allow the attacker to leverage the compromise of a few nodes to exert control over much of the network .Then attacker use the replica node to inject fake data and disr...

In object-based systems, objects supporting abstract methods are replicated to increase the performance, reliability, and availability. We discuss a novel objectbased locking (OBL) protocol to lock replicas of objects by extending the quorum-based protocol for read and write to abstract methods. Unless two methods conflict, subsets of the replicas locked by the methods do not intersect even if ...

Replication in the World-Wide Web covers a wide range of techniques. Often, the redirection of a client browser towards a given replica of a Web page has to be explicit and is performed after the client’s request has reached the Web server storing the requested page. As an alternative, we propose to perform the redirection as close to the client as possible in a fully distributed manner. Distri...

We study the thermodynamics of discrete breathers by transforming a lattice of weakly coupled nonlinear oscillators into an effective Ising pseudospin model. We introduce a replica ensemble and investigate the effective system susceptibilities through the replica overlap distribution. We find that a transition occurs at a given temperature to a new phase characterized by a slow decay of the rel...

A generalised integer S Ising spin glass model is analysed using the replica formalism. The bilinear couplings are assumed to have a Gaussian distribution with ferromagnetic mean < Jij >= J0. Incorporation of a quadrupolar interaction term and a chemical potential leads to a richer phase diagram with transitions of first and second order. The first order transition may be interpreted as a phase...

We study the stability of the replica-symmetric solution of a two-sublattice infinite-range spin-glass model, which can describe the transition from an antiferromagnetic to a spin-glass state. The eigenvalues associated with replica-symmetric perturbations are in general complex. The natural generalization of the usual stability condition is to require the real part of these eigenvalues to be p...

In a recent breakthrough Kanzieper showed that it is possible to obtain exact nonperturbative random matrix results from the replica limit of the corresponding Painlevé equation. In this article we analyze the replica limit of the Toda lattice equation and obtain exact expressions for the two-point function of the Gaussian unitary ensemble and the resolvent of the chiral unitary ensemble. In th...

In this paper we review the predictions of the replica approach on the probability distribution of the overlaps among replicas and on the sample to sample fluctuations of this probability. We stress the role of replica equivalence in obtaining relations which do not depend on the form of replica symmetry breaking. A comparison is done with the results obtained with a different rigorous approach...

This paper presents transactional replication, a novel approach for replicating distributed objects. It uses non-blocking synchronisation techniques to realise software transactional memory for ensuring replica consistency. Unlike traditional passive object replication, which executes requests on a single primary, our approach allows using an arbitrary replica to execute a client request. Fine-...