1. Chapter 3 - 1 Chapter 3 Internet Agents

2. Chapter 3 - 2 Contents Background Web Search Agents Information Filtering Agents Notification Agents Other Service Agents

3. Chapter 3 - 3 Background The dominant form of Web usage is the direct manipulation method (surfing). The characteristics of the Web dictate why we need Internet agents for information brokering. –The volume of information on the Internet is huge. –The type of information on the Internet varies widely. –The quality of information varies greatly. –The depth-first surfing inherently encouraged by Web browser causes most users to be lost in Web hyper space. Internet agents are computer programs that reside on those servers and access the distributed on-line information on the Internet to perform tasks on behalf of users without direct user interaction.

4. Chapter 3 - 4 Background Categorization –Web search agents –Information filtering agents –Off-line delivery agents –Notification agents –Service agents –Web site agents –Mobile agents

5. Chapter 3 - 5 Web Search Agents Web Browser Query Server Index Database WebRobot Search Engine Web User Also known as softbot, spiders, wanderers, crawlers.

6. Chapter 3 - 6 Web Search Agents The performance of a search engine can be measured by its precision and recall. Precision the document relevant to the query the total number of document returned Recall the document relevant to the query the total number of document

7. Chapter 3 - 7 Web Robots The Web robot is an autonomous agent that communicates with the Web using, for example, the HTTP protocol. The software robots have different strategies for traversing the Web graph. Robots usually use a strategy to traverse the Web graph in a prioritized manner. –Lycos uses a queue to store all the pointers in the page. –Web Crawler uses a breadth-first Robots may exclude different types of documents such as pictures and binary files.

8. Chapter 3 - 8 Web Robots

9. Chapter 3 - 9 Web Robots

10. Chapter 3 - 10 Information Filtering Agents While search agents are useful in finding Web sites of particular interest to a user, information filtering agents find the content of particular interest to a user using different information sources. Web Browser News Server Index Articles User Profile Indexing Engine Web Filtering Agent

11. Chapter 3 - 11 Information Filtering Agents The indexing engine binds keywords to each article. Most information retrieval systems model documents as terms and term frequency counts. Document model representations can be roughly divided into two groups: –Vector space models, Tree structures Most information retrieval systems also generate the thesaurus classes by synonyms in order to index words by word stems. The similarity between two documents can be determined by a suitable distance metric –Term Frequency * Inverse Document Frequency of TfIDf

12. Chapter 3 - 12 NewsHound — Personalized Newspaper Searches the stories in the San Jose Mercury News as well as several other newspapers to find articles that match a user’s profile. Uses the Verity Topic indexing engine with an email and Web form style interface. See Fig. 3.5, p. 61

13. Chapter 3 - 13 Benefits of Information Filtering Agents Benefits: see Table 3.4, p. 62 What can information filtering agents do for your organization? –Brings the latest HW configuration and pricing information for a purchasing manager –delivers the international, financial, political, and economic news that impact a financial investment –Tracks news related to an ongoing investigation for law enforcement agency personnel –Gathers news about job market conditions for a special employment category for a human resources professional

14. Chapter 3 - 14 Off-line Delivery Agents Information filtering agents that deliver personalized information in a locally viewable format without requiring a direct Internet connection. When does an information filtering agent that delivered customized information via an email message become an off- line delivery agent? –When the information agent has its own information delivery software on the desktop for automatic information delivery and management of delivered information.

15. Chapter 3 - 15 Off-line Delivery Agents

16. Chapter 3 - 16 Notification agents A notification agent notifies users of events of significance to them when an event is a change in the state of information such as: –Content change in a particular Web page –Search engine additions for specified keyword queries –User-specified reminders for special event such as birthday. Internet notification agents are typically server-based programs that poll user-specified sites.

17. Chapter 3 - 17 Notification agents Methods employed –HTTP “If-Modified-Since” request: This is a special Head Request that returns a document only if the page has been modified since the specified date. –Text only retrieval: Notification agents will retrieve only the text of a page without the graphics and hyperlinks, and parse the retrieved text to determine any change in the published information. –Embedded HTML extensions: These are directions to notification agents embedded in HTML document by publishers.

18. Chapter 3 - 18 Other Service Agents Announcement agents –Remind users of important occasions that are customized for personal needs. Book agents: –Track newly released books that match a user’s reading interests. Business information monitoring agents: –Monitor the exchange of information on the Internet relating to services, products, industry, and companies. Classified agents: –Search a database of classified ads daily to find a user- specified item, and notify the user via mail.

19. Chapter 3 - 19 Other Service Agents Direct mail agents: –Bring personalized direct mail advertising that matches the user’s stated personal background, activities, and lifestyle. Financial service agents: –Deliver email messages containing price and financial news for a personalized portfolio of securities and mutual funds. Food and wine agents –Remember each user’s previous purchases and tasting notes to make customized presentation of inventory during the next visit. Job agents: –Serve as virtual recruiters to find employees that match employer job profiles.

20. Chapter 3 - 20 Other Service Agents Entertainment agents: –Finds communities with similar interests to those of the user, and recommends albums. Movies, and so on based on group evaluations Shopping agents: –Perform comparison shopping for user-specified items at virtual stores. Site agents: –Functions as a virtual host at 3D and client sites

21. Chapter 3 - 21 Other Service Agents Grouping based on their internal architectures: –Agents that perform intelligent database queries and notify users –Agents that use a parallel search algorithm to query Web resources and integrate query results on behalf of the user –Agents that use collaborative filtering to find user clusters for recommendations based on social communities –Agents that use natural language techniques to engage in conversations with users