Learn More
The rapid growth of interconnected computer networks has generated a lot of interest in migrating the distributed systems to a wide area network (WAN) environment, such as the Internet. We have developed mechanisms for studying the performance of the distributed transaction processing on the Internet, without actually having to move the database sites to(More)
Multiversion concurrency control schemes are often limited in their practicability due to their storage requirements for multiple versions of the data. However, a class of multiver-sion schemes utilize only the versions, maintained for the purpose of recovery, to improve the concurrency by allowing the concurrent execution of "non conflicting" read-write(More)
We describe the model and implementation of two approaches for method execution in distributed object query processing. The first approach is the traditional data migration approach in which remote data accesses (if required) are made to compose an in-memory object at the query site which is followed by method invocation on this object. The second approach(More)
Three major technical issues can be identified in th e design of the digital part of the audiovisual library of Bibliotheque Nationale de France : digitizing policies, end-user interface issues for time-base d media and real-time media impact on network an d software design. Two specific factors have to be considered with special care in the research(More)
Digital libraries are a repository of documents that are large volumes of integrated text, image, video and sound data. In such an environment, users may not have an eecient access mechanisms for the data, and in some cases may not even know what is available and how and where it is located. To facilitate the users in retrieving the documents from this vast(More)
1'0 submit. Jar public(/./.ion "'1. We present the clesigll and implementation of a dist.ributed object based database system, called O-Raid. O-Raid design embodies the extellsion of.\.U exisl.ing distributed relational database system called Raid, to provide support for Rbstract <Ia.ta types. Our design and implementation 7'i'1.IJ,eS relational database(More)
Efficiency in query processing is a major issue to achieve performance in future database applications. Dynamic method execution and object referencing (both inter and intra object referencing) are two features of object query languages like SQL-2 and SQL-3. These features add great power to the users in presenting their inqueries to the database systems.(More)
We discuss the adaptable features in a video conferencing system and how they can be tuned to preserve video quality when the network performance degrades. We present the implementation of two such features { resolution reduction and frame resizing { in an existing video conferencing software called NV developed at Xerox PARC. The savings in transmission(More)
  • 1