Nowadays, grid systems are vital technology for programs running with high performance and problems solving with largescale in scientific, engineering and business. In grid systems, heterogeneous computational resources and data should be shared between independent organizations that are scatter geographically. A data grid is a kind of grid types that make relations computational and storage re...

This thesis examines the provision of on-demand multimedia streaming services using clusters of commodity PCs. In the proposed HammerHead multimedia server cluster architecture, a dynamic content replication policy is used to assign non-disjoint subsets of the presentations in a multimedia archive to cluster nodes. Replicas of selected presentations can be created on more than one node to achie...

Replicating for performance constitutes an important issue in large-scale data management systems. In this context, a significant number of replication strategies have been proposed for data grid systems. Some works classified these strategies into static vs. dynamic or centralised vs. decentralised or client vs. server initiated strategies. Very few works deal with a replication strategy class...

Data Grid is an infrastructure that manages huge amount of data files, and provides intensive computational resources across geographically distributed collaboration. To increase resource availability and to ease resource sharing in such environment, there is a need for replication services. Data replication is one of the methods used to improve the performance of data access in distributed sys...

A prevalent view of DNA replication has been that it is carried out in fixed "replication factories." By tracking the progression of sister replication forks with respect to genetic loci in live Escherichia coli, we show that at initiation replisomes assemble at replication origins irrespective of where the origins are positioned within the cell. Sister replisomes separate and move to opposite ...

Cloud Storage Providers (CSPs) offer geographically data stores providing several storage classes with different prices. An important problem facing by cloud users is how to exploit these storage classes to serve an application with a time-varying workload on its objects at minimum cost. This cost consists of residential cost (i.e., storage, Put and Get costs) and potential migration cost (i.e....

In recent years, grid technology has had such a fast growth that it has been used in many scientific experiments and research centers. A large number of storage elements and computational resources are combined to generate a grid which gives us shared access to extra computing power. In particular, data grid deals with data intensive applications and provides intensive resources across widely d...

Dynamic replication is a technique that can be used by clustered multimedia servers to evaluate the demand for individual streams and selectively replicate or move content to facilitate load balancing. In this paper we explain the motivation for using dynamic replication and provide a brief description of some existing dynamic replication policies. We present a new policy called Dynamic RePacki...

Task Scheduling is a critical design issue of distributed computing. The emerging Grid computing infrastructure consists of heterogeneous resources in widely distributed autonomous domains and makes task scheduling even more challenging. Grid considers both static, unmovable hardware and moveable, replicable data as computing resources. While intensive research has been done on task scheduling ...

The precise coordination of the different steps of DNA replication is critical for the maintenance of genome stability. We have probed the mechanisms coupling various components of the replication machinery and their response to polymerase stalling by inhibition of the DNA polymerases in living mammalian cells with aphidicolin. We observed little change in the behaviour of proteins involved in ...