Content Delivery Networks (CDN) design entails the placement of server replicas to bring the content close to the users, together with an efficient and content aware request routing. In this paper we address the problem of dynamic replica placement to account for users demand variability while optimizing the costs paid by a CDN provider and the overall performance of the distributed replica ser...

Most of the frequent techniques in text mining are based on the arithmetic scrutiny of a idiom, either word or slogan. Arithmetical scrutiny of a term incidence captures the consequence of the term within a manuscript only. However, two provisos can have the similar regularity in their documents, but one term contributes more to the connotation of its sentences than the further term. Thus, the ...

We find a new solution of the renormalization group for the Potts model with ferromagnetic random valued coupling constants. The solution exhibits universality and broken replica symmetry. It is argued that the model reaches this universality class if the replica symmetry is broken initially. Otherwise the model stays with the replica symmetric renormalization group flow and reaches the fixed p...

Fault tolerance schemes for mobile agents to survive agent server crash failures are complex since developers normally have no control over remote agent servers. Some solutions modify the agent server platform, e.g. a replica of the mobile agent is injected into stable storage upon its arrival at an agent server. However in the event of an agent server crash the replica remains unavailable unti...

Parallel Tempering (PT), also known as Replica Exchange, is a powerful Markov Chain Monte Carlo sampling approach which aims at reducing the relaxation time in simulations of physical systems. In this paper, we present a novel implementation of PT, so-called decentralized replica exchange PT, using MPI and the Scalable Parallel Random Number Generators (SPRNG) libraries. By adjusting the replic...

Abstrtict— A general gain-enhancement technique for operational amplifiers using a replica amplifier is described. Unlike conventional techniques such as cascoding, which increases the gain by increasing the output resistance, the replica-amp technique increases the gain by matching the main and the replica amps. Among the advantages of the replica-amp technique are low supply, high swing, and ...

Data replication is a well-known technique used in distributed systems in order to improve fault tolerance and make data access faster. Several copies of a dataset are created and placed at different nodes, so that users can access the replica closest to them, and at the same time the data access load is distributed among the replicas. In today’s Grid middleware solutions, data management servi...

In this thesis, new generalizations of the Bethe approximation and new understanding of the replica method are proposed. The Bethe approximation is an efficient approximation for graphical models, which gives an asymptotically accurate estimate of the partition function for many graphical models. The Bethe approximation explains the well-known message passing algorithm, belief propagation, whic...

Data Grid is a new kind of data management infrastructure. To improve access efficiency, large amounts of data on Data Grids need to be replicated in the form of replicas at distributed sites. Due to the limited storage capacity, a good replica replacement algorithm is needed. This paper proposes a replica replacement algorithm based on value-cost prediction, which achieves a good balance betwe...

In systems that use primary-backup replication for fault-tolerance, maintaining system availability after failures refers not just to ensuring the liveness of application functionality at a backup replica but also to ensuring that the state of the promoted backup matches that of the failed primary. Traditionally these availability criteria are realized in middleware through sophisticated algori...