The design and prototype implementation of the XCAT Grid Science Portal is described in this paper. The portal lets grid application programmers easily script complex distributed computations and package these applications with simple interfaces for others to use. Each application is packaged as a "notebook" which consists of web pages and editable parameterized scripts. The portal is a workstation-based specialized "personal" web server, capable of executing the application scripts and launching remote grid applications for the user. The portal server can receive event streams published by the application and grid resource information published by Network Weather Service (NWS) [32] or Autopilot [15] sensors. Notebooks can be "published" and stored in web based archives for others to retrieve and modify. The XCAT Grid Science Portal has been tested with various applications, including the distributed simulation of chemical processes in semiconductor manufacturing and collaboratory support for X-ray crystallographers.

Describes an approach to building a distributed software component system for scientific and engineering applications that is based on representing Computational Grid services as application-level software components. These Grid services provide tools such as registry and directory services, event services and remote component creation. While a service-based architecture for grids and other distributed systems is not new, this framework provides several unique features. First, the public interfaces to each software component are described as XML documents. This allows many adaptors and user interfaces to be generated from the specification dynamically. Second, this system is designed to exploit the resources of existing Grid infrastructures like Globus and Legion, and commercial Internet frameworks like e-speak. Third, and most important, the component-based design extends throughout the system. Hence, tools such as application builders, which allow users to select components, start them on remote resources, and connect and execute them, are also interchangeable software components. Consequently, it is possible to build distributed applications using a graphical "drag-and-drop" interface, a Web-based interface, a scripting language like Python, or an existing tool such as Matlab.

Grid systems, such as Globus, Legion and Globe, provide an infrastructure for implementing metacomputing over the Internet. The Component Architecture Toolkit (CAT) provides a software layer above the grid that facilitates programming and end-user interaction with the grid.