Abstract. We are developing a semantic data framework for virtual observatories. A Virtual Observatory provides online location, retrieval, and analysis services to a variety of heterogeneous scientific data sources. We employ semantic technologies to integrate data and provide “intelligent

We have used semantic technologies to design, implement, and deploy an interdisciplinary virtual observatory. The Virtual Solar-Terrestrial Observatory is a production data framework providing access to observational datasets. It is in use by a community of scientists, students, and data providers

review the "Grid problem," which we define as flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources---what we refer to as virtual organizations. In such settings, we encounter unique authentication, authorization, resource access

Aegis operations are 10–100 times faster than Ultrix,a mature monolithic UNIX operating system. ExOS implements processes, virtual memory, and inter-process communication abstractions entirely within a library. Measurements show that ExOS’s application-level virtual memory and IPC primitives are 5

to form networked virtual supercomputers or metacomputers. While the physical infrastructure to build such systems is becoming widespread, the heterogeneous and dynamic nature of the metacomputing environment poses new challenges for developers of system software, parallel tools, and applications

-backed coup deposed the reformist government of Col. Jacobo Arbenz Guzmán in 1954. Moderates of the political center. embattled but alive in E1 Salvador, have virtually disappeared in Guatemala-joining more than 30.000 victims of terror over the last tifteen vears. “The situation in Guatemala is much more

Grid technologies enable large-scale sharing of resources within formal or informal consortia of individuals and/or institutions: what are sometimes called virtual organizations. In these settings, the discovery, characterization, and monitoring of resources, services, and computations

The U-Net communication architecture provides processes with a virtual view of a network interface to enable userlevel access to high-speed communication devices. The architecture, implemented on standard workstations using offthe-shelf ATM communication hardware, removes the kernel from

The difficulty of developing reliable distributed softwme is an impediment to applying distributed computing technology in many settings. Expeti _ with the Isis system suggests that a structured approach based on virtually synchronous _ groups yields systems that are substantially easier to develop

The large-scale behavior of routing in the Internet has gone virtually without any formal study, the exception being Chinoy's analysis of the dynamics of Internet routing information [Ch93]. We report on an analysis of 40,000 end-to-end route measurements conducted using repeated “traceroutes