1. emory notre dame oregon state virginia tech The OCKHAM / NSDL Digital Library Services Registry A Distributed Approach To Enable End-to-End Digital Service Resolution

2. emory notre dame oregon state virginia tech

3. Funded by the National Science Foundation National Science Digital Library Program 2 Year Project Funding

4. emory notre dame oregon state virginia tech Goals 1.Create a Registry for all possible Digital Library Services 2.Enable End-to-End Digital Library Service Resolving Sub-Goals 1.Ensure DLSR is Scalable and Redundant 2.Ensure Manageability of DLSR is Scalable 3.Use Existing Standards and Technologies

5. emory notre dame oregon state virginia tech Use of the DLSR 1.Library Portal Use Case 2.Metasearch Use Case 3.Personal Digital Library 3 Examples

6. emory notre dame oregon state virginia tech Distributed DLSR The OCKHAM/NSDL DLSR is Distributed Many nodes over the network Scalability Redundancy Approach in part based on DNS model

7. emory notre dame oregon state virginia tech A Brief History of DNS Hosts.txt file (later just hosts) ARPAnet started with centralized management Inter-NIC Eventually, a more manageable approach was needed Current Distributed DNS System was created Allows De-centralized administration Hierarchical design Simplifies management Reduces bandwith, bottlenecks Reduces duplicate name issue (i.e..edu,.com, etc.)

8. emory notre dame oregon state virginia tech Distributed DLSR Reasoning much the same as DNS Similarities and Differences

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11. Data Layer Relational Db & OJB Synchronized Database Interchangeability Ease of development Lucene Fast indexing on the fly indexing Flexible query engine

12. emory notre dame oregon state virginia tech Interface Layer Current Interfaces Struts powered J2ee interface OAICat - OAI-PMH 2.0 Future Interfaces SRU/W Z39.50 OpenURL Output Formats Html XML

13. emory notre dame oregon state virginia tech Clients Web browser OAI-PMH Z39.50 Any web enabled application.

14. emory notre dame oregon state virginia tech Network Layer JXTA provides low level network functionality –Peer identification and discovery –Transport layer PeerManager provides modular application level functionality –Load Management –Client/Server Modules Main Registry Modules –URL Server –Harvester Client

15. emory notre dame oregon state virginia tech Using OAI For Propagating Data A peer can query any other peer and receive an incremental update Queries are based on the latest record modification date for the peers local copy of the set Subsequent queries will use the new latest record modification date

16. emory notre dame oregon state virginia tech Hierarchal Network Topology Topology Requirements Data must propagate to all peers Compensation for inherent instability of P2P networks Scalable structure Low overhead DNS for Digital Library Services

17. emory notre dame oregon state virginia tech Put the pieces together

18. emory notre dame oregon state virginia tech OCKHAM Future Expand the DLSR Community and Use Explore and build DLSR-aware tools and services Prototype semi-automated creation of DLs

19. emory notre dame oregon state virginia tech Further Information OCKHAM Website – http://ockham.org Martin Halbert, Emory – mhalber@emory.edu Jeremy Frumkin, Oregon State University – jeremy.frumkin@oregonstate.edu