We discuss replica analytic continuation using several simple models in order to prove mathematically the validity of replica analysis, which is used in a wide range of fields related to large scale complex systems. While replica analysis consists of two analytical techniques, the replica trick (or replica analytic continuation) and the thermodynamical limit (and/or order parameter expansion), ...

With non-GEO constellations the primary means of counteracting the shadowing and the blockage effects is through the use of the satellite diversity, i.e. multiple satellites in the constellation are simultaneously visible to user. The probability system availability is improved by increasing the probability at least one satellite is in clear Line Of Sight. In the selection diversity (SD) scheme...

Parallel data transmission based on multi-copy can enhance transmission speed and ensure the QoS of data grid greatly. The status of network and replica node, the distance of replica node, the time and bandwidth of service requester will directly affect service cost. How to take the above factors into account, so as to provide basis for node selection and bandwidth allocation, guarantee the tim...

Content Delivery Networks (CDN) aim at overcoming the inherent limitations of the Internet. The main concept at the basis of this technology is the delivery at edge points of the network, in proximity to the request areas, to improve the user’s perceived performance while limiting the costs. This paper focuses on the main research areas in the field of CDN, pointing out the motivations, and ana...

In this work, we address the problem of replica selection in distributed query processing over the Web, in the presence of user preferences for Quality of Service and Quality of Data. In particular, we propose RAQP, which stands for Replication-Aware Query Processing. RAQP uses an initial statically-optimized logical plan, and then selects the execution site for each operator and also selects w...

We develop a method to evaluate the generalized degrees of freedom (GDF) for linear regression with sparse regularization. The GDF is a key factor in model selection, and thus its evaluation is useful in many modelling applications. An analytical expression for the GDF is derived using the replica method in the largesystem-size limit with random Gaussian predictors. The resulting formula has a ...

This paper describes our work on the implementation and empirical evaluation of a client-side server selection framework for accessing replicated web services. The framework, which incorporates five representative server selection policies, was evaluated in the context of accessing a real-world replicated service, with four replicas distributed over three different continents. Our empirical res...

Data Grid replication is critical for improving data intensive applications performance, providing fault tolerance and load balancing. Most of the techniques for data replication use Giggle as a framework for Replica Location Services (RLS), combined with other services for replica selection and optimization. Our previous work have proposed an enhanced Giggle framework, that simplify the locati...

Proactive recovery is technique that periodically rejuvenates the components of a replicated system. When used in the context of intrusion-tolerant systems, in which faulty replicas may be under control of some adversary, it allows the removal of intrusions from the compromised replicas. However, since the set of vulnerabilities remains the same, the adversary can take advantage of the previous...