5463 26 web mining

Papers
 Web Mining: Pattern Discovery from World Wide
Web Transactions
 Bomshad Mobasher, Namit Jain, Eui-Hong (Sam) Han,
Jaideep Srivastava; Technical Report 96-050, University
of Minnesota, Sep, 1996.
 Visual Web Mining
 Amir H. Youssefi, David J. Duke, Mohammed J. Zaki;
WWW2004, May 17–22, 2004, New York, New York,
USA. ACM 1-58113-912-8/04/0005.

Web Mining – The Idea
 In recent years the growth of the World Wide
Web exceeded all expectations. Today there
are several billions of HTML documents,
pictures and other multimedia files available
via internet and the number is still rising. But
considering the impressive variety of the web,
retrieving interesting content has become a
very difficult task.
Presented by: Anushri Gupta

Web Mining
 Web is the single largest data source in the
world
 Due to heterogeneity and lack of structure of
web data, mining is a challenging task
 Multidisciplinary field:
 data mining, machine learning, natural language
 processing, statistics, databases, information
 retrieval, multimedia, etc.
The 14th International World Wide Web Conference (WWW-2005),
May 10-14, 2005, Chiba, Japan
Web Content Mining
Bing Liu

Opportunities and Challenges
 Web offers an unprecedented opportunity and challenge to
data mining
 The amount of information on the Web is huge, and easily accessible.
 The coverage of Web information is very wide and diverse. One can
find information about almost anything.
 Information/data of almost all types exist on the Web, e.g., structured
tables, texts, multimedia data, etc.
 Much of the Web information is semi-structured due to the nested
structure of HTML code.
 Much of the Web information is linked. There are hyperlinks among
pages within a site, and across different sites.
 Much of the Web information is redundant. The same piece of
information or its variants may appear in many pages.
The 14th International World Wide Web Conference (WWW-2005),
May 10-14, 2005, Chiba, Japan
Web Content Mining
Bing Liu

Opportunities and Challenges
 The Web is noisy. A Web page typically contains a mixture of many
kinds of information, e.g., main contents, advertisements, navigation
panels, copyright notices, etc.
 The Web is also about services. Many Web sites and pages enable
people to perform operations with input parameters, i.e., they provide
services.
 The Web is dynamic. Information on the Web changes constantly.
Keeping up with the changes and monitoring the changes are
important issues.
 Above all, the Web is a virtual society. It is not only about data,
information and services, but also about interactions among people,
organizations and automatic systems, i.e., communities.

Web Mining
 The term created by Orem Etzioni (1996)
 Application of data mining techniques to
automatically discover and extract information from
Web data

Data Mining vs. Web Mining
 Traditional data mining
 data is structured and relational
 well-defined tables, columns, rows, keys,
and constraints.
 Web data
 Semi-structured and unstructured
 readily available data
 rich in features and patterns

Web Data
 Web Structure
 tag
 Click here to
Shop Online

Web Data
 Web Usage
 Application Server logs
 Http logs

Classification of Web Mining Techniques
 Web Content Mining
 Web-Structure Mining
 Web-Usage Mining

Web-Structure Mining
 Generate structural summary about the Web
site and Web page
Depending upon the hyperlink, „Categorizing the Web
pages and the related Information @ inter domain level
Discovering the Web Page Structure.
Discovering the nature of the hierarchy of hyperlinks in
the website and its structure.
Web Mining
Web Usage
Mining
Web Content
Mining
Web Structure
Mining
Presented by: Gaurao Bardia

Web-Structure Mining cont…
 Finding Information about web pages
 Inference on Hyperlink
Retrieving information about the relevance and the quality
of the web page.
Finding the authoritative on the topic and content.
The web page contains not only information but also
hyperlinks, which contains huge amount of annotation.
Hyperlink identifies author‟s endorsement of the other web
page.

Web-Structure Mining cont…
 More Information on Web Structure Mining
Web Page Categorization. (Chakrabarti 1998)
Finding micro communities on the web
e.g. Google (Brin and Page, 1998)
Schema Discovery in Semi-Structured Environment.

Web-Usage Mining
 What is Usage Mining?
Web Mining
Web Usage
Mining
Web Content
Mining
Web Structure
Mining
Discovering user „navigation patterns‟ from web data.
Prediction of user behavior while the user interacts
with the web.
Helps to Improve large Collection of resources.

Web-Usage Mining cont…
 Usage Mining Techniques
Data Preparation
Data Collection
Data Selection
Data Cleaning
Data Mining
Navigation Patterns
Sequential Patterns

 Data Mining Techniques – Navigation Patterns
Web Mining
Web Usage
Mining
Web Content
Mining
Web Structure
Mining
Web Page Hierarchy
of a Web Site
A
B
C D
E

 Data Mining Techniques – Navigation Patterns
Analysis:
Example:
70% of users who accessed /company/product2 did so by starting
at /company and proceeding through /company/new,
/company/products and company/product1
80% of users who accessed the site started from
/company/products
65% of users left the site after
four or less page references

 Data Mining Techniques – Sequential Patterns
Example:
Supermarket
Cont…
Customer Transaction Time Purchased Items
John 6/21/05 5:30 pm Beer
John 6/22/05 10:20 pm Brandy
Frank 6/20/05 10:15 am Juice, Coke
Frank 6/20/05 11:50 am Beer
Frank 6/20/05 12:50 am Wine, Cider
Mary 6/20/05 2:30 pm Beer
Mary 6/21/05 6:17 pm Wine, Cider
Mary 6/22/05 5:05 pm Brandy

Customer Sequence
Customer Customer Sequences
John (Beer) (Brandy)
Frank (Juice, Coke) (Beer) (Wine, Cider)
Mary (Beer) (Wine, Cider) (Brandy)
Example:
Supermarket
Cont…
Sequential Patterns with Supporting
Support >= 40% Customers
(Beer) (Brandy) John, Frank
(Beer) (Wine, Cider) Frank, Mary
Mining Result

Web usage examples
 In Google search, within past week 30% of users who visited
/company/product/ had ‘camera’ as text.
 60% of users who placed an online order in
/company/product1 also placed an order in /company/product4
within 15 days

Web Content Mining
 ‘Process of information’ or resource discovery from
content of millions of sources across the World Wide
Web
 E.g. Web data contents: text, Image, audio, video,
metadata and hyperlinks
 Goes beyond key word extraction, or some simple
statistics of words and phrases in documents.
Web Mining
Web Usage
Mining
Web Content
Mining
Web Structure
Mining

Web Content Mining
 Pre-processing data before web content mining:
feature selection (Piramuthu 2003)
 Post-processing data can reduce ambiguous
searching results (Sigletos & Paliouras 2003)
 Web Page Content Mining
 Mines the contents of documents directly
 Search Engine Mining
 Improves on the content search of other tools like search
engines.

Web Content Mining
 Web content mining is related to data mining
and text mining. [Bing Liu. 2005]
 It is related to data mining because many data
mining techniques can be applied in Web content
mining.
 It is related to text mining because much of the
web contents are texts.
 Web data are mainly semi-structured and/or
unstructured, while data mining is structured and
text is unstructured.

Tech for Web Content Mining
 Classifications
 Clustering
 Association

Document Classification
 Supervised Learning
 Supervised learning is a ‘machine learning’ technique for creating a
function from training data .
 Documents are categorized
 The output can predict a class label of the input object (called
classification).
 Techniques used are
 Nearest Neighbor Classifier
 Feature Selection
 Decision Tree

Feature Selection
 Removes terms in the training documents which are
statistically uncorrelated with the class labels
 Simple heuristics
 Stop words like “a”, “an”, “the” etc.
 Empirically chosen thresholds for ignoring “too
frequent” or “too rare” terms
 Discard “too frequent” and “too rare terms”

Document Clustering
 Unsupervised Learning : a data set of input objects is gathered
 Goal : Evolve measures of similarity to cluster a collection of
documents/terms into groups within which similarity within a cluster
is larger than across clusters.
 Hypothesis : Given a `suitable„ clustering of a collection, if the user is
interested in document/term d/t, he is likely to be interested in other
members of the cluster to which d/t belongs.
 Hierarchical
 Bottom-Up
 Top-Down
 Partitional

Semi-Supervised Learning
 A collection of documents is available
 A subset of the collection has known labels
 Goal: to label the rest of the collection.
 Approach
 Train a supervised learner using the labeled subset.
 Apply the trained learner on the remaining documents.
 Idea
 Harness information in the labeled subset to enable
better learning.
 Also, check the collection for emergence of new topics

Association
Web Mining
Web Usage
Mining
Web Content
Mining
Web Structure
Mining
Example: Supermarket
Transaction ID Items Purchased
1 butter, bread, milk
2 bread, milk, beer, egg
3 diaper
… ………
 An association rule can be
“If a customer buys milk, in 50% of cases, he/she also
buys beers. This happens in 33% of all transactions.
50%: confidence
33%: support
Can also Integrate in Hyperlinks

Presented by: Ankush Chadha
Web Mining : Pattern Discovery from
World Wide Web Transactions
Bamshad Mobasher, Namit Jain, Eui-Hong(Sam) Han, Jaideep Srivastava
{mobasher,njain,han,srivasta}@cs.umn.edu
Department of Computer Science
University of Minnesota
4-192 EECS Bldg., 200 Union St. SE
Minneapolis, MN 55455 USA
March 8,1997

Web Usage Mining
 Restructure a website
 Extract user access patterns to target ads
 Number of access to individual files
 Predict user behavior based on previously learned rules and
users‟ profile
 Present dynamic information to users based on their interests
and profiles
Discovery of meaningful patterns from data
generated by client-server transactions on one or
more Web localities

Web Usage Data
Sources
- Server access logs
- Server Referrer logs
- Agent logs
- Client-side cookies
- User profiles
- Search engine logs
- Database logs
The record of what actions a user takes with
his mouse and keyboard while visiting a site.

Transfer / Access Log
 The transfer/access log contains detailed information about each request that the
server receives from user‟s web browsers.
CLIENT
SERVER
Time Date Hostname File Requested Amount of data
transferred
Status of the
request

Agent Log
 The agent log lists the browsers (including version number and the platform)
that people are using to connect to your server.
CLIENT
SERVER
Hostname Version Number Platform

Referrer Log
 The referrer log contains the URLs of pages on other sites that link to your pages.
That is, if a user gets to one of the server‟s pages by clicking on a link from another
site, that URL of that site will appear in this log.
CLIENT
SERVER
B
Page A
Page B
URL REFERRER URL

Error Log
 The error log keeps a record of errors and failed requests.
 A request may fail if the page contains links to a file that does not exist or
if the user is not authorized to access a specific page or file.
CLIENT
SERVER

Web Usage Data Preprocessing
DATA CLEANING
- Clean/Filter raw data to eliminate redundancy
LOGICAL CLUSTERS
- Notion of Single User Transaction

There are a variety of files accessed as a result of a request by a
client to view a particular Web page.
These include image, sound and video files, executable cgi files ,
coordinates of clickable regions in image map files and HTML files.
Thus the server logs contain many entries that are redundant or
irrelevant for the data mining tasks
Data Cleaning
Page1.html
a.gif
b.gif
User Request : Page1.html
Browser Request : Page1.html, a.gif, b.gif
3 Entries for same user request in the Server Log,
hence redundancy.

Hostname Date : Time Request
SOLUTION
Data Cleaning cont…
All the log entries with filename suffixes such as, gif, jpeg, GIF, JPEG, JPG
and map are removed from the log.

Logical Clusters
Representation of a Single User Transaction.
One of the significant factors which distinguish Web mining from other
data mining activities is the method used for identifying user transactions
The clustering is based on comparing pairs of log entries and
determining the similarity between them by means of some kind of
distance measure.
Entries that are sufficiently close are grouped together
PROBLEMS:
To determine an appropriate set of attributes to cluster.
To determine an appropriate distance metrics for them.

Time Dimension for clustering the log entries
Logical Clusters
Let L be a set of server access log entries
A log entry l Є L includes -
the client IP address l.ip,
the client user id l.uid,
the URL of the accessed page l.url and
the time of access l.time
Δt = Time Gap
l1.time – l2.time < = tΔ

PARTITIONING
- Logical Clusters are partitioned based on IP Address and User Ids
Logical Cluster Post Processing

Association Rules
X == > Y (support, confidence)
60% of clients who accessed /products/, also accessed
/products/software/webminer.htm.
30% of clients who accessed /special-offer.html, placed an online
order in /products/software/.

Mining Sequential Patterns
Support for a pattern now depends on the ordering of the items,
which was not true for association rules.
For example: a transaction consisting of URLs ABCD in that
order contains BC as an subsequence, but does not contain CB
60% of clients who placed an online order for WEBMINER,
placed another online order for software within 15 days

Clustering & Classification
 clients who often access /products/software/webminer.html
tend to be from educational institutions.
 clients who placed an online order for software tend to be
students in the 20-25 age group and live in the United States.
 75% of clients who download software from
/products/software/demos/ visit between 7:00 and 11:00 pm on
weekends.

WWW2004, May 17–22, 2004, New York, New York, USA.
ACM 1-58113-912-8/04/0005
Amir H. Youssefi David J. Duke Mohammed J. Zaki
Rensselaer Polytechnic Institute University of Bath Rensselaer Polytechnic Institute
youssefi@cs.rpi.edu d.duke@bath.ac.uk zaki@cs.rpi.edu
Presented by : Krati Jain
Visual Web Mining

Abstract
Analysis of web site usage data involves two significant challenges
 Volume of data
 Structural complexity of web sites
Visual Web Mining
 Apply Data Mining and Information Visualization techniques to web domain
 Aim : To correlate the outcomes of mining Web Usage Logs and the extracted
Web Structure, by visually superimposing the results.

Terminology
 Information Visualization
use of computer-supported, interactive,visual representations of abstract data
to amply cognition
 User Session
compact sequence of web accesses by a user
 Visual Web Mining
- application of Information Visualization techniques on results of Web Mining
- to further amplify the perception of extracted patterns, rules and regularities

 provides a prototype implementation for applying information
visualization techniques to the results of Data Mining.
 Visualization to obtain :
- understanding of the structure of a particular website
- web surfers‟ behavior when visiting that site
 Due to the large dataset and the structural complexity of the sites, 3D
visual representations used.
 Implemented using an open source toolkit called the Visualization
ToolKit (VTK).
Visual Web Mining Framework

Visual Web Mining Architecture

 Input : web pages and web server log files
 A web robot (webbot) is used to retrieve the pages of the website.
 In parallel, Web Server Log files are downloaded and processed through
a sessionizer and a LOGML file is generated.
 The Integration Engine is a suite of programs for data preparation,
i.e., cleaning, transforming and integrating data.

 The Visualization Stage : maps the extracted data and attributes into
visual images, realized through VTK extended with support for graphs.
 VTK : set of C++ class libraries accessible through
- linkage with a C++ program, or
- via wrappings supported for scripting languages (Tcl, Python or Java),
here tcl script used.
 Result : interactive 3D/2D visualizations which could be used by analysts
to compare actual web surfing patterns to expected patterns

Results
VWM provides an insight into specific, focused, questions that form a
bridge between high-level domain concerns and the raw data :
 What is the typical behavior of a user entering our website?
 What is the typical behavior of a user entering our website in page A from
„Discounted Book Sales‟ link on a referrer web page B of another web
site?
 What is the typical behavior of a logged in registered user from Europe
entering page C from link named “Add Gift Certificate” on page A?

Visual Representation
 analogy between the „flow‟ of user click streams through a website, and
the flow of fluids in a physical environment in arriving at new
representations.
 representation of web access involves locating „abstract‟ concepts (e.g.
web pages) within a geometric space.
 Structures used:
- Graphs
Extract tree from the site structure, and use this as the
framework for presenting access-related results through glyphs and
color mapping.
- Stream Tubes
Variable-width tubes showing access paths with different traffic are
introduced on top of the web graph structure.

This is a visualization of the
web graph of the Computer
Science department of
Rensselaer Polytechnic
Institute(http://www.cs.rpi.edu).
Strahler numbers are used for
assigning colors to edges.
One can see user access paths
scattering from first page of website
(the node in center) to cluster of
web pages corresponding to
faculty pages, course home pages,
etc.
Design and Implementation of Diagrams

Adding third dimension enables
visualization of more information and
clarifies user behavior in and between
clusters. Center node of circular
basement is first page of web site
from which users scatter to different
clusters of web pages. Color spectrum
from Red
(entry point into clusters) to Blue (exit
points) clarifies behavior of users.
This is a 3D visualization of web
usage for above site.The cylinder like
part of this figure is visualization of
web usage of surfers as they browse
a long HTML document.

User’s browsing access pattern is
amplified by a different
coloring. Depending on link structure
of underlying
pages, we can see vertical access
patterns of a user drilling down the
cluster, making a cylinder shape
(bottom-left corner of the figure). Also
users following links going down a
hierarchy of webpages makes a cone
shape and users going up
hierarchies,e.g., back to main page of
website makes a funnel shape
(top-right corner of the figure).

Right: One can observe long user sessions as strings falling off clusters. Those are special type of
long sessions when user navigates sequence of web pages which come one after the other under
a cluster, e.g., sections of a long document. In many cases we found web pages with many nodes
connected with Next/Up/Previous hyperlinks.
Left: A zoom view of the same visualization

Frequent access patterns
extracted by web mining
process are visualized as a
white graph on top of
embedded and colorful graph
of web usage.

Similar to last figure with
addition of another attribute,
i.e., frequency of pattern which
is rendered as thickness of
white tubes; this would
significantly help analysis of
results.

Future Work
A number of further tasks could be added:
 Demonstrating the utility of web mining can be done by making exploratory
changes to web sites, e.g., adding links from hot parts of web site to cold parts
and then extracting, visualizing and interpreting changes in access patterns.
 There is often a tension in the design of algorithms between accommodating a
wide range of data, or customizing the algorithm to capitalize on known
constraints or regularities.
 Also web content mining can be introduced to implementations of this
architecture.

5463 26 web mining

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