A two-tier Web caching and replication system, called the INTELSAT Internet Delivery System (IDS) is discussed. Based on a Warehouse-Kiosk paradigm, IDS provides global access and Internet wormholes via a fleet of INTELSAT satellites, the largest commercial satellite communications system in the world. Web content such as cacheable HTTP, FTP and streaming objects are fetched or pushed both acti...

Mobile nodes in some challenging network scenarios, e.g. battlefield and disaster recovery scenarios, suffer from intermittent connectivity and frequent partitions. Disruption Tolerant Network (DTN) technologies are designed to enable communications in such environments. Several DTN routing schemes have been proposed. However, not much work has been done on designing schemes that provide effici...

Reliable data multicast is problematic. ACK/NACK schemes do not scale to large audiences, and simple data replication wastes network bandwidth. Fcast, “file multicasting”, combines multicast with Forward Error Correction (FEC) to address both these problems. Like classic multicast, Fcast scales to large audiences, and like other FEC schemes, it uses bandwidth very efficiently. Some of the benef...

Redundant data management is a must in client server information systems with mobile clients. Based on the level of autonomy of mobile devices/ users techniques for handling such data can be divided into caching, hoarding, and replication. These three terms are often used incorrectly in the literature. To our knowledge the exact definition of the terms has never been published in an internation...

Distributed Shared Memory (DSM) combines the scalability of loosely coupled multicomputer systems with the ease of usability of tightly coupled multiprocessors, and allows transparent replication and caching of data. DSM has received much attention in the past decade and many consistency models, protocols, and systems were developed. In this paper, we describe a new software DSM system called J...

We characterize the dynamic data management problem for location based services(LBS) in mobile environments and devise a cost model for servicing both location independent and location dependent data. The cost analysis leads to a set of dynamic data management strategies that employs judicious caching, proactive server pushing and neighborhood replication to reduce service cost and improve resp...

As systems become more distributed, they also become more complex. To ensure consistent execution while maximizing availability, distributed applications use various mechanisms such as replication, load balancing, and data caching. The protocols used for consistency management and component availability are traditionally instantiated by the application. However, in distributed object-based envi...

Computational science applications performing distributed computations using grid networks are now emerging. These applications have new and demanding requirements for efficient query processing. In order to meet these requirements, we have developed the DASCOSA-DB distributed database system. In this chapter, a detailed overview of the architecture and implementation of DASCOSA-DB is given, as...

In this paper we describe a flexible object storage system aimed at supporting collaborative applications in largescale environments that include mobile computers. We present an integrated solution to two major problems that arise in such environments: data availability and concurrency control. The first is tackled by the flexible combination of weakly consistent server replication and client c...