Biblio

Scientific applications built on wide-area distributed systems such as emerging cloud based architectures and the legacy grid computing infrastructure often struggle with user adoption even though they succeed from a systems research perspective. This paper examines the coupling of user-centered design processes with modern distributed systems. Further in this paper, we describe approaches for conceptualizing a product that solves a recognized need: to develop a data gateway to serve the data management and research needs of experimentalists of electron microscopes and similar shared scientific instruments in the context of a research service laboratory. The purpose of the data gateway is to provide secure, controlled access to data generated from a wide range of scientific instruments. From the functional perspective, we focus on the basic processing of raw data that underlies the lab's "business" processes, the movement of data from the laboratory to central access and archival storage points, and the distribution of data to respective authorized users. Through the gateway interface, users will be able to share the instrument data with collaborators or copy it to remote storage servers. Basic pipelines for extracting additional metadata (through a pluggable parser framework) will be enabled. The core contribution described in this paper, building on the aforementioned distributed data management capabilities, is the adoption of user-centered design processes for developing the scientific user interface. We describe the user-centered design methodology for exploring user needs, iteratively testing the design, learning from user experiences, and adapting what we learn to improve design and capabilities. We further conclude that user-centered design is, in turn, best enabled by an adaptable distributed systems framework. A key challenge to implementing a user-centered design is to have design tools closely linked with a software system architecture that can evolve over time while providing a highly available data gateway. A key contribution of this paper is to share the insights from crafting such an evolvable design-build-evaluate-deploy architecture and plans for iterative development and deployment.

Science Gateways bridge multiple computational grids and clouds, acting as overlay cyber infrastructure. Gateways have three logical tiers: a user interfacing tier, a resource tier and a bridging middleware tier. Different groups may operate these tiers. This introduces three security challenges. First, the gateway middleware must manage multiple types of credentials associated with different resource providers. Second, the separation of the user interface and middleware layers means that security credentials must be securely delegated from the user interface to the middleware. Third, the same middleware may serve multiple gateways, so the middleware must correctly isolate user credentials associated with different gateways. We examine each of these three scenarios, concentrating on the requirements and implementation of the middleware layer. We propose and investigate the use of a Credential Store to solve the three security challenges.