Internet agents
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Internet Agents. Web search Agents Information filtering agents Off-line delivery agents Notification agents Service agents Web site agents Mobile agents. Information Search. Ways to Find Information Browsing: Following hyper-links that seem of interest

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Internet agents

Internet Agents

  • Web search Agents

  • Information filtering agents

  • Off-line delivery agents

  • Notification agents

  • Service agents

  • Web site agents

  • Mobile agents


Information search

Information Search

  • Ways to Find Information

    • Browsing: Following hyper-links that seem of interest

    • Searching: Sending a query to a search engine such as Lycos

    • Categories: Following existing categories such as Yahoo

  • Problems

    • Spent a lot of time and effort to navigate. Can search be made more efficient?

    • Search but it is difficult to accurately express the user’s intention.

    • Search engines are not personalized


Search engines web etiquette guidelines for spiders

Search EnginesWeb etiquette guidelines for spiders

  • Identify the name of the agent

  • Identify the user deploying the agent

  • Announce the agent by posting a message to the comp.infosystems.www.providers Usenet newsgroups

  • Announce the agent to the Webmasters of the servers the agent will visit

  • Provide additional information (using the Referrer field)

  • Be accessible to fix problems the agent may cause

  • Design the agent so it does not consume lot of resources (e.g. does not use successive hits on a single server, does not loop, runs at appointed times, etc.)


Advantages and disadvantages of search engines

Advantages and Disadvantages of Search Engines


Limitations of current search engines

Limitations of current search engines

  • Lack of personalization; this results in low precision of answers

  • Unscaleability: *the robot must visit not only new links but also old ones to keep them up to date; *the information gathering is centralized

    Some solutions to scalability issues:

  • use specialized information brokers for building information indices

  • use massive replication and caching of popular information

  • distributed information gathering by placing gatherers on the provider’s site; thus information is ready for analysis as new information comes in, but the provider must implement the software.


Information filtering agents

Information Filtering Agents

  • Information Filtering agents find the content of interest to a user.

  • Information Filtering agents could gather information from different sources

  • They could filter information based on user’s personal interest

  • Filtering agents typically use a fixed number for information sources

  • Information filtering agents may use Information Retrieval techniques

    *Vector space models, where a document is represented as a vector of attributes

    *Tree structure, which represents a hierarchical view of a document


Filtering agents attributes

Filtering Agents Attributes


Internet agents

Filtering Agent Architecture


Filtering agent architecture

Filtering Agent Architecture

Figure 3.4 Filtering based on word usage

Insignificant

Low-frequency

words

Insignificant

High-frequency

words

Words usage frequency


Benefits of information filtering agents

Benefits of Information Filtering Agents


Functionality of webmate

Functionality of WebMate

  • Learning user’s interests for information filtering

    • Multiple TF-IDF vectors representation

    • Incremental and adaptive Learning

    • Compile personal newspaper

  • Support for efficiently finding information

    • Automatic refinement using Trigger Pairs

    • Relevance feedback

_____________________________

Chen, Sycara, “WebMate: A Personal Agent for Browsing and Searching”,

Proceedings of the Second International Conference on Autonomous Agents, Minneapolis, MN, May 1998


Profile representation

Profile Representation

  • Multiple TF-IDF vectors representation

  • How many vectors are used? (Settable parameters; depends on # User’s interests, Computational complexity)

  • How many dimensions are used in a vector? (Computational complexity, typical lexicons in a domain)


Learning algorithm

Learning Algorithm

  • Preprocess: Parse HTML page, delete stop words, stemming

  • Extract TF-IDF vector of the current interesting document

  • If the number of vectors in the profile is less than predefined number, add the vector to the profile

  • Otherwise, calculate the cosine similarity between every two TF-IDF vectors in the profile

  • Combine the two vectors with the greatest similarity.

  • Sort the weights in the new vector in decreasing order and keep the highest several elements


Compile personal newspaper

Compile Personal Newspaper

  • Automatically spide a list of URLs or Construct a query from the profile

  • Calculate the similarity and check whether the similarity is greater than some threshold

  • Experiments: Accuracy in top 10 is between 50% and 60%; Accuracy in top 20 is about 50%; Accuracy in the whole is about 30%


Search refinement

Search Refinement

  • Trigger Pairs Based Automated Refinement

    • If a word S is significantly¹ correlated with another word T, then (S, T) is considered a “trigger pair”, with S being the trigger and T the triggered word.

  • Relevance Feedback

    • The context of the search keywords in the “relevant” pages is used to automatically refine the search

  • Parallel Search and Rerank

  • Similarity-based Query

___________________

¹Significance is measured by mutual information (MI):


Examples of trigger pairs

Examples of Trigger Pairs

  • Broadcast News Corpus: 140M words, Distance between S and T is 500

  • Examples1: product << {maker,company, corporation, industry, incorporate, sale, computer, market, business,…}

  • Example 2: car <<{motor, auto, model, maker, vehicle, for, buick, honda, inventory, assembly, chevrolet, sale, …}

  • Example 3: fare << {airline, maxsaver, carrier, discount, air, coach, flight, traveler, continental, unrestrict, ticket,…}

  • Example 4: music << {symphony, orchestra, composer, song, concert, tune, concerto, sound, musician, album, …}


Automatic search refinement

Automatic Search Refinement

  • The user chooses the domain, and the system automatically expands the query using domain specific triggers or ontology

  • The user chooses the intended definition of the ambiguous words, and the system according to the definition expands the query

  • For a search with only one keyword, the top several triggers to the keyword are used to expand the search

  • For a search with more than 2 keywords, the intersection of the triggers to the keywords are used to expand the search


Relevance feedback algorithm

Relevance Feedback Algorithm

  • The context of the search keywords in the “relevant” pages is used to refine the search

  • Given a relevant page, the system looks for the context of the keywords, and calculates the frequency in order to use the top several frequent words to expand the query


The query restart problem

The Query Restart Problem

  • Agent A sends query to Agent B.

  • Agent B can complete the query in time X, where

    • X = 1 with probability p.

    • X = c (c > 1) with probability 1 - p.

      Expectation: EX = p + (1 -p) c

  • If not done by time 1, should agent A abort and restart, or wait?

  • Can restarting reduce expectation? The variance? Both?

  • Does it help to repeatedly restart k times?

_______________________

Chalasani, Jha, Shehory, Sycara, “Query Restart Strategies for Web Agents”,Proceedings of Autonomous Agents 98, Minneapolis, MN, May 1998


A simple scenario single restart

A Simple Scenario: Single restart

Strategy: restart just after time 1, if not done by then.

Let Xi = completion time of i'th query, i = 1,2.

X1, X2 are independent, identically distributed.

New completion time is Y:

Y =

New expectation

EY = p + (1 - p)(1 + E X2)(X1, X2 indep.)

= 1 + p (1 - p) + (1 - p)c

If (and only if) c > 1 + 1 / p, EY < X1 !

{

1 if X1 = 1,

1 + X2 if X1 = c.


A simple scenario k restarts

A Simple Scenario: k Restarts

Number of Restarts k


Off line delivery agents

Off-Line Delivery Agents

Off-line Delivery of Agents Attributes

ElementDescription

EnvironmentInternet, news feeds

Task skillsInformation

KnowledgeWeb, news, finance, sports, weather

Communication skillsHTTP, Meta tags, Desktop OS

Information filtering agents that deliver personalized information without the need for a direct Internet connection


Benefits of off line delivery agents

Benefits of Off-line Delivery Agents


Notification agents

Notification Agents

A notification agent is one that notifies a user of significant events, i.e. a change in the state of information, e.g.

  • Content change in a particular Web page

  • Search engine additions for specific keyword queries

  • User-specified reminders for personal events (e.g. birthdays)

  • Notification Agent Attributes


Benefits of notification agents

Benefits of Notification Agents


Other service agents

Other Service Agents

  • Announcement Agents

  • Business information monitoring agents

  • Classified ads agents: search database of ads

  • Direct mail agents: deliver direct mail advertising

  • Financial service agents: deliver e-mails with prices or other financial news

  • Food and wine agents

  • Job agents: virtual recruiters to find appropriate employees

  • Entertainment agents: find communities of interests similar to the user and recommend items, such as music, movies etc.

  • Shopping agents: comparison shopping for user-specified items

  • Site agents: virtual hosts at sites


Shopbots

Shopbots

Advantages:

  • Provide unified interface to different stores, thus mitigating need to navigate and deal with different interfaces

  • Find best price and availability of a product

    Challenges

  • Virtual stores stop agents since they do not want to be compared on price and availability alone

  • User’s trust in a shopbots’s ability to notice sales and promotions.

    Solutions:

  • Cooperative vendor/agent model

  • Vendor form learning agent


Collaborative filtering

Collaborative Filtering

A collaborative filtering system makes recommendations based on the preferences of similar users.

People: Yenta, Referral Web

Products: Firefly, Tunes, Syskill & Webert

Readings: Wisewire, Phoaks


Content vs collaboration

Content vs. Collaboration

  • Content-based retrieval returns documents that are similar to a query (search) or a user profile (preference)

  • Collaborative recommendation retrieves documents liked by others with similar profiles


Early apps

Early Apps

  • Group Lens (1994) Filtered newsgroups.. news client displays predicted scores & user rates after reading..

  • Phoaks Recommended webpages.. uses frequency of mention data within Usenet news groups to rate URL’s


Getting the data

Getting the Data

Explicit: Firefly

rate match recommend

Implicit: Amazon

purchase match recommend

Priming the Pump: Lifestyle Finder uses demographic data to assign users to market research categories

Over the Shoulder: Letizia uses observed browsing behavior & heuristics to recommend links


Problems in collaborative filtering

Problems in Collaborative Filtering

Incentives & Startup

  • Need a critical mass of users/recommenders to make meaningful predictions

  • Need mechanisms to maintain participation

    Reliability

  • Spoofing- will content providers inflate their ratings

  • Technical problems with clustering & similarity measures

    Privacy

  • Once you share your profile who else may want it?


Synthetic agents e g julia

Synthetic Agents (e.g. Julia)

Julia is a chatterbot that tries to convince users of its humanlike behavior:

  • ·Repeating user’s input in questions

  • ·Admitting ignorance

  • ·Changing the topic of conversation

  • ·Using conversational statements

  • ·Using humorous statements

  • ·Providing excerpts fro Usenet News

  • ·Simulating typing, mimicking a user’s imperfect performance

    Possible applications of chatterbots:

  • ·Visiting on-line chatroooms on topics of interest to your company

  • ·Initiating interesting conversations in chatrooms

  • ·Presenting comparison ads against your rivals

  • ·Querying information requests about your products

  • ·Serving as a site guide for finding information

  • ·Serving as a product guide on your site (e.g. demonstrate an automobile)


Intranets

Intranets

Business applications of intranets:

  • Effective communication medium for enterprises

  • Create virtual communities within an enterprise

  • Automating order tracking and transaction

  • processing

  • Marketing support automation

  • Customer service and knowledge sharing among customers

  • Internal help desk to provide guidance for corporate processes and resources

  • Human resources support


Benefits of intranet search agents

Benefits of Intranet Search Agents


Intranet filtering agent attributes

Intranet Filtering Agent Attributes


Benefits of intranet filtering agents

Benefits of Intranet Filtering Agents


Internet agents

Drawbacks and extended features

Drawbacks include:

·Separate notification for each user interest, cluttering mailbox

·Do not incorporate user model for tracking user’s actions upon information delivery

Advanced Features

·Recommend an agent for each new user interest topic

·Modify an existing agent, based on user’s use of agent recommended information (e.g. specialize an information agent)

·Remove an agent that the user does not use

·Temporally activate an agent based on user interest and disinterest in the agent’s recommendation


Internet agents

Collaboration Agents

The software runs over a network and enables a team to work together and share information. It assists groups in:

·Group scheduling

·Discussion groups

·Resource tracking

·Document Management

 It could do some simple tasks:

·Save and re-execute shareable queries that search groupware data bases

·Perform a script under pre-specified conditions

·Perform a script according to pre-specified schedule


Internet agents

Example: Lotus Notes

Agent definition

·Agent name with optional comment

·When the agent should run:

*manually

*if new mail has arrived

*if documents have been created, modified, deleted

*at scheduled times, e.g. hourly, daily etc

  • What document should the agent act on?

  • *all documents

  • *all new and modified documents since last time agent ran

  • *all unread documents

  • *selected documents

  • What should the agent do?

  • *User can enter LotusScript program that can examine named fields, and apply simple conditional logic.


Internet agents

Process Automation Agents

The goal is to use agents to automate workflow in business applications

Differences between traditional workflow and agent-based workflow

·Traditional workflow is centralized; agents offere a distributed infrastructure

·Traditional workflow works only in structured environments; agents could manage workflow during execution

·Traditional workflow pre-specifies paths to take for

exception handling: agents can negotiate new tasks and

resources dynamically


Attributes of process automation agents

Attributes of Process Automation Agents


Advantages of process agents

Advantages of Process Agents


Internet agents

Database Agents

Agents that provide Enterprise-based support

·Run scheduled database analyses in the background

·Exception reporting for operations management

·Notify of information changes in a user-specified database object


Database agents enterprise data delivery system

Database Agents: Enterprise data delivery system

OLAP

Server

DSS Agent

Desktop

VLDB Drivers

Oracle

Informix

SQL

Server

. . .

Server


Database agents attributes

Database Agents Attributes


Database agent benefits

Database Agent Benefits


Desired features of database agents

Desired Features of Database Agents

Exception reporting alerts

·Time or event triggered report execution

·Workflow actions triggered by reports

·Incorporation of learning capability into the Database agents

·Incorporation of learning into the OLAP server


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