Data replication is a common method used to improve the performance of data access in distributed systems. In this paper, two dynamic replication algorithms, Simple Bottom-Up (SBU) and Aggregate Bottom-Up (ABU), are proposed for the multitier Data Grid. A multi-tier Data Grid simulator called DRepSim is developed for studying the performances of the dynamic replication algorithms. The simulatio...

Replication involves creating and maintaining copies of services and data provided by a distributed system. Unlike communication, without which it is impossible to build a distributed system, replication is not a fundamental principle. This means that it is possible to build a distributed system that does not make use of replication. Replication does, however, become important when reliability,...

Replication involves creating and maintaining copies of services and data provided by a distributed system. Unlike communication, without which it is impossible to build a distributed system, replication is not a fundamental principle. This means that it is possible to build a distributed system that does not make use of replication. Replication does, however, become important when reliability,...

Replication is an essential utility in mobile environments. Mobile units not connected to xed networks are left with their own data resources which may or may not contain the necessary data. This paper describes beneets and problems using replication in mobile infrastructures. We compare diierent replication approaches for xed and mobile systems. We show that traditional protocols are inadequat...

Replication is an essential utility in mobile environments. Mobile units not connected to xed networks are left with their own data resources which may or may not contain the necessary data. This paper describes beneets and problems using replication in mobile infrastructures. We compare diierent replication approaches for xed and mobile systems. We show that traditional protocols are inadequat...

Hadoop, an open source implementation of the MapReduce framework, has been widely used for processing massive-scale data in parallel. Since Hadoop uses a distributed file system, called HDFS, the data locality problem often happens (i.e., a data block should be copied to the processing node when a processing node does not possess the data block in its local storage), and this problem leads to t...

In our days, there are many real-time applications that use data which are geographically dispersed. The distributed real-time database management systems (DRTDBMS) have been used to manage large amount of distributed data while meeting the stringent temporal requirements in real-time applications. Providing Quality of Service (QoS) guarantees in DRTDBMSs is a challenging task. To address this ...