1. Information Retrieval Homework #1 Members: Wesley, Lbr, Shuang CSIE, NCU

2. Outline Introduction Stemming Algorithm Suffix Tree Performance Conclusion

3. Stemming Algorithm (optional) Goal of stemming – improve performance and require less resources by reducing the number of unique words –Ex. “ computable ”, “ computation ”, “ computability ” Porter Algorithm (most commonly accepted)

4. Suffix Tree Library libsfxdisk-1.2 is a Fast indexing library based on suffix tree Storing, retrieving, deleting and dumping/loading the database

5. Indexing Dir Name File Name Stem File Reader Dir Reader Filter Suffix Tree Delete Stop Words Index File (Optional)

6. Searching Search Engine Index Key Word Print Out Results

7. Performance Total Indexing Time –Spend more time –One file take about one minute Average searching time –very quick http://140.115.156.49/~wesley/IR.html

8. Future To add stemming scheme To limit indexing time Additional searching –AND, OR