Suleman & Fox: A Framework for Building Open Digital Libraries

-- "Open" DLs build directly on concepts/philosophies of Open Archives Initiative.

-- Most existing systems classified as DLs resulted from custom-built software dev projects - each involves intensive design, implementation & testing cycles. why repeat effort? some software toolkits: Dienst, Repository-in-a-box etc

-- Most programming enviro's adapt a component model.

-- OAI launched october 1999. Focuse on high-level comm among systems & simplicity of protocal.

-- OAI protocol for Metadate Harvesting (OAI-PMH): system of interconnected components. OAI protocal can be thought of as glue that binds together components of a larger DL (or collaborative system of DLs)

** DLs modeled as networks of extended OAs, with each OA being a source of data and/or provider of services. This approach closely resembles the way physical libraries work.

-- research & production DLs differ

-- ODLs guided by a set of design principals & operationalized with aid of OAI-PMH extensions. proven techniques from internet development: simplicity of protocols, openness of standards, loose coupling of systems, purposeful orthogonality, reuse whenever possible.

-- Formal Principals:
1. All DL services should be encapsulated within components that are extensions of OAs
2. All access to DL services should be through their extended OAI interfaces
3. Semantics of OAI protocol should be extended or overloaded as allowed by OAI protocol, but without contradicting essential meaning.
4. All DL services should get access to other data sources using extended OAI protocol
5. Dls should be constructed as networks of extended OAs.

-- OAI Harvester obtains data stream which creates indices for searching.

-- Components in prototype systems:
1. Union: combine metadata from mult sources
2. Filter: reformat metadata from non-OAI data sources
3. Search: search-engine functionality
4. Browse: category-driven browsing functionality
5. Recent: sample of recently added items

-- Tested on NDLTD system w/ good feedback.

-- Designing by principles & implementing for real-world scenario.