1. Design of a Search Engine for Metadata Search Based on Metalogy Ing-Xiang Chen, Che-Min Chen,and Cheng-Zen Yang Dept. of Computer Engineering and Science Yuan-Ze University http://syslab.cse.yzu.edu.tw/ ICADL 2001 - 2001/12/11

2. czyang@acm.orgYZU, Taiwan - ICADL2001 2 Outline Introduction Related Technologies System Architecture An Experimental Prototype Conclusions Future work

3. czyang@acm.orgYZU, Taiwan - ICADL2001 3 Introduction Metadata management is not an easy task: – It requires specific domain knowledge for appropriate data categorization. –It needs to deal with the complicated relationships between the metadata items. –A good management tool for easing metadata construction and manipulation is necessary.

4. czyang@acm.orgYZU, Taiwan - ICADL2001 4 Introduction Metalogy –Metalogy is a management system developed by ROSS project group in Taiwan. –It can be used to manipulate various digitized items and export/import XML records. –It is mainly designed for metadata management of each digital library.

5. czyang@acm.orgYZU, Taiwan - ICADL2001 5 Introduction Search across digital libraries: –Metalogy does not consider how to search information across digital libraries. –As digital libraries are widely deployed, searching information across several digital libraries becomes important. –We design a search engine to help users find resources without connecting to digital libraries and inputting the same query terms.

6. czyang@acm.orgYZU, Taiwan - ICADL2001 6 Introduction We design this search engine based on the XML data exported from Metalogy for some reasons: –XML/Metalogy provides comprehensive metadata descriptions and DTD information for metadata search. –The quality of the distributed service highly depends on the quality of the data resource.

7. czyang@acm.orgYZU, Taiwan - ICADL2001 7 Related Technologies Z39.50 –It was proposed to search and retrieve information from heterogeneous databases over networks. –Provide abstract search capability. –It is difficult to be implemented because of its strengthened functionality. OAI – Arc –Arc is developed for cross-archive searching. –It adopts the OAI protocol to harvest digital archives.

8. czyang@acm.orgYZU, Taiwan - ICADL2001 8 Related Technologies Harp –Harp provides a uniform query interface across legacy public libraries through HarpSQL. –A HarpSQL server acts as a query agent for storing and handling the intermediate query results not as a search engine to collect and store all metadata. METALICA –It adopts a meta-search engine like MetaCrawler to provide a uniform user interface for supporting cross- archive search.

9. czyang@acm.orgYZU, Taiwan - ICADL2001 9 System Architecture XML XML Parser (Java Application) Index Database Search Engine (Java Servlet) DTD Manager (Java Servlet) User Interface Manager Interface Query Request Metadata DTD Digital Library 1 DTD Browser ‧ ‧ Digital Library n Digital Library 2

10. czyang@acm.orgYZU, Taiwan - ICADL2001 10 System Architecture The search engine is constructed with three modules: –Search engine module Provide an integrated user interface Adopt Java servlets to provide search services –Index database module Provide metadata repository for digital library sources. Adopt simple Dublin Core set as default metadata. Store DTD mapping relationships.

11. czyang@acm.orgYZU, Taiwan - ICADL2001 11 System Architecture –Metadata/DTD manager Provide an administration interface to manage XML/DTD mapping relationships. Parse and translate the XML/DTD documents provided by remote digital libraries. Gather information from remote digital libraries and update the index database repeatedly.

12. czyang@acm.orgYZU, Taiwan - ICADL2001 12 An Experimental Prototype Development tool: –Implement this search engine with Java to reach platform-independence. –Parse XML information with JAXP (Java API for XML parsing) package. –The database is constructed with a public domain database MySQL.

13. czyang@acm.orgYZU, Taiwan - ICADL2001 13 An Experimental Prototype XML/DTD manager Manage functionality

14. czyang@acm.orgYZU, Taiwan - ICADL2001 14 An Experimental Prototype A mapping example Mapping information

15. czyang@acm.orgYZU, Taiwan - ICADL2001 15 An Experimental Prototype An search example A famous calligrapher His-Chih Wang (303- 361 AD)

16. czyang@acm.orgYZU, Taiwan - ICADL2001 16 An Experimental Prototype Search results Matched metadata Link to the resource file

17. czyang@acm.orgYZU, Taiwan - ICADL2001 17 Conclusions Present the design of a search engine for searching information across digital libraries based on metadata/XML. The design of the search engine has three advantages: –First, the system architecture is simple and the cost is low.

18. czyang@acm.orgYZU, Taiwan - ICADL2001 18 Conclusions –Second, the system extensibility is high for newly required services. –Third, users need not to know how and where to search information by using this uniform user interface.

19. czyang@acm.orgYZU, Taiwan - ICADL2001 19 Future Work The quality control on the metadata provided by the original digital library source. The mapping scheme to support more heterogeneous digital archives should be further discussed.

20. czyang@acm.orgYZU, Taiwan - ICADL2001 20 Future Work The performance issue should be further addressed when the environment is in a large scale. How to effectively update information from the remote digital libraries is another important work to do.