CAP 4770: Introduction to Data Mining Fall 2010 Dr. Tao Li Florida International University Self-Introduction • Ph.D. from University of Rochester, 2004 • Associate Professor in the School of Computer Science at Florida International University • Research Interest – – – – Data Mining Machine Learning Information Retrieval Bioinformatics • Industry Experience: – Summer internships at Xerox Research (summer 2001, 2002) and IBM Research (Summer 2003, 2004) CAP 4770 2 My Research Projects • You can find on http://www.cis.fiu.edu/~taoli CAP 4770 3 Student Self-Introduction • Name – I will try to remember your names. But if you have a Long name, please let me know how should I call you • Major and Academic status • Programming Skills – Java, C/C++, VB, Matlab, Scripts etc. • Anything you want us to know – e.g., I am a spurs fan. CAP 4770 4 Acknowledgements • Some of the material used in this course is drawn from other sources: • Prof. Christopher W. Clifton at Purdue • Prof. Jiawei Han at UIUC • Profs. Pang-Ning Tan (Michigan State University), Michael Steinbach and Vipin Kumar (University of Minnesota) CAP 4770 5 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues – Curse of Dimensionality CAP 4770 6 Course Overview • Meeting time – T/Th 2:00pm – 3:15pm • Office hours: – Tuesday 5:00pm – 6:00pm or by appointment • Course Webpage: – http://www.cs.fiu.edu/~taoli/class/CAP4770F10/index.html – Lecture Notes and Assignments CAP 4770 7 Course Objectives This is an introductory course for junior/senior computer science undergraduate students on the topic of Data Mining. Topics include data mining applications, data preparation, data reduction and various data mining techniques (such as association, clustering, classification, anomaly detection) CAP 4770 8 Assignments and Grading • • • • • • Reading/Written Assignments Research Projects Midterm Exams Final Project/Presentations Class attendance is mandatory. Evaluation will be a subjective process – Effort is very important component • • • • Class Participation: 10% Quizzes: 10% Exams: 30% Assignments: 50% – Final Project: 15% – Written Homework: 15% – Other Projects: 20% CAP 4770 9 Text and References • Jiawei Han and Micheline Kamber. Data Mining: Concepts and Techniques. • Ian H. Witten and Eibe Frank. Data Mining: Practical Machine Learning Tools and Techniques with Java Implementations. CAP 4770 10 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues – Curse of Dimensionality CAP 4770 11 Why Data Mining? • Motivation: “Necessity is the Mother of Invention” • Data explosion problem – Applications generate huge amounts of data • WWW, computer systems/programs, biology experiments, Business transactions, Scientific computation and simulation, Medical and person data, Surveillance video and pictures, Satellite sensing, Digital media, – Technologies are available to collect and store data • Bar codes, scanners, satellites, cameras etc. • Databases, data warehouses, variety of repositories … – We are drowning in data, but starving for knowledge! CAP 4770 12 What Is Data Mining? • Data mining (knowledge discovery from data) – Extraction of interesting (non-trivial, implicit, previously unknown and potentially useful) patterns or knowledge from huge amount of data • What is not data mining? – (Deductive) query processing. – Expert systems or small ML/statistical programs • Key Characteristics – Combination of Theory and Application – Engineering Process • Data Pre-processing and Post-processing, Interpretation – Collection of Functionalities • Different Tasks and Algorithms – Interdisciplinary Field CAP 4770 13 Real Example from NBA • AS (Advanced Scout) software from IBM Research – Coach can assess the effectiveness of certain coaching decisions • Good/bad player matchups • Plays that work well against a given team • Raw Data: Play-by-play information recorded by teams – Who is on court – Who took a shot, the type of shot, the outcome, any rebounds CAP 4770 14 AS Knowledge Discovery • Text Description – When Price was Point-Guard, J. Williams made 100% of his jump field-goal-attempts. The total number of such attempts is 4. • Graph Description Starks+Houston+ Ward playing Shooting Percentage Overall 0 20 40 60 Reference: Bhabdari et al. Advanced Scout: Data Mining and Knowledge Discovery in NBA Data. Data Mining and Knowledge Discovery, 1, 121-125(1997) CAP 4770 15 Ads vs. search results Ads vs. search results • Search advertising is the revenue model – Multi-billion-dollar industry – Advertisers pay for clicks on their ads • Interesting problems – What ads to show for a search? – If I’m an advertiser, which search terms should I bid on and how much to bid? Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues – Curse of Dimensionality CAP 4770 19 Potential Applications • Data analysis and decision support – Market analysis and management • Target marketing, customer relationship management (CRM), market basket analysis, cross selling, market segmentation – Risk analysis and management • Forecasting, customer retention, improved underwriting, quality control, competitive analysis – Fraud detection and detection of unusual patterns (outliers) • Other Applications – – – – Text mining (news group, email, documents) and Web mining Stream data mining System and Network Management Multimedia Applications • Music, Image, Video – DNA and bio-data analysis CAP 4770 20 Example: Use in retailing • Goal: Improved business efficiency – Improve marketing (advertise to the most likely buyers) – Inventory reduction (stock only needed quantities) • Information source: Historical business data – Example: Supermarket sales records Date/Time/Register 12/6 13:15 2 12/6 13:16 3 Fish N Y Turkey Y N Cranberries Y N Wine N Y ... ... ... – Size ranges from 50k records (research studies) to terabytes (years of data from chains) – Data is already being warehoused • Sample question – what products are generally purchased together? • The answers are in the data, if only we could see them CAP 4770 21 Other Applications • Network System management – Event Mining Research at IBM • Astronomy – JPL and the Palomar Observatory discovered 22 quasars with the help of data mining • Internet Web Surf-Aid – IBM Surf-Aid applies data mining algorithms to Web access logs for market-related pages to discover customer preference and behavior pages, analyzing effectiveness of Web marketing, improving Web site organization, etc. CAP 4770 22 Market Analysis and Management (1) • Where are the data sources for analysis? – Credit card transactions, loyalty cards, discount coupons, customer complaint calls, plus (public) lifestyle studies • Target marketing – Find clusters of “model” customers who share the same characteristics: interest, income level, spending habits, etc. • Determine customer purchasing patterns over time – Conversion of single to a joint bank account: marriage, etc. • Cross-market analysis – Associations/co-relations between product sales – Prediction based on the association information CAP 4770 23 Market Analysis and Management (2) • Customer profiling – data mining can tell you what types of customers buy what products (clustering or classification) • Identifying customer requirements – identifying the best products for different customers – use prediction to find what factors will attract new customers • Provides summary information – various multidimensional summary reports – statistical summary information (data central tendency and variation) CAP 4770 24 Corporate Analysis and Risk Management • Finance planning and asset evaluation – cash flow analysis and prediction – contingent claim analysis to evaluate assets – cross-sectional and time series analysis (financialratio, trend analysis, etc.) • Resource planning: – summarize and compare the resources and spending • Competition: – monitor competitors and market directions – group customers into classes and a class-based pricing procedure – set pricing strategy in a highly competitive market CAP 4770 25 Fraud Detection and Management (1) • Applications – widely used in health care, retail, credit card services, telecommunications (phone card fraud), etc. • Approach – use historical data to build models of fraudulent behavior and use data mining to help identify similar instances • Examples – auto insurance: detect a group of people who stage accidents to collect on insurance – money laundering: detect suspicious money transactions (US Treasury's Financial Crimes Enforcement Network) – medical insurance: detect professional patients and ring of doctors and ring of references CAP 4770 26 Fraud Detection and Management (2) • Detecting inappropriate medical treatment – Australian Health Insurance Commission identifies that in many cases blanket screening tests were requested (save Australian $1m/yr). • Detecting telephone fraud – Telephone call model: destination of the call, duration, time of day or week. Analyze patterns that deviate from an expected norm. – British Telecom identified discrete groups of callers with frequent intra-group calls, especially mobile phones, and broke a multimillion dollar fraud. • Retail – Analysts estimate that 38% of retail shrink is due to dishonest employees. CAP 4770 27 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues – Curse of Dimensionality CAP 4770 28 Data Mining: An Engineering Process – Data mining: interactive and iterative process. Interpretation/ Evaluation Mining Algorithms Knowledge Preprocessing Patterns Selection Preprocessed Data Data Target Data adapted from: U. Fayyad, et al. (1995), “From Knowledge Discovery to Data Mining: An Overview,” Advances in Knowledge Discovery and Data Mining, U. Fayyad et al. (Eds.), AAAI/MIT Press CAP 4770 29 Steps of a KDD Process • Learning the application domain – relevant prior knowledge and goals of application • Creating a target data set: data selection • Data cleaning and preprocessing: (may take 60% of effort!) • Data reduction and transformation – Find useful features, dimensionality/variable reduction, invariant representation. • Choosing functions of data mining – summarization, classification, regression, association, clustering. • Choosing the mining algorithm(s) • Data mining: search for patterns of interest • Pattern evaluation and knowledge presentation – visualization, transformation, removing redundant patterns, etc. • Use of discovered knowledge CAP 4770 30 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues – Curse of Dimensionality CAP 4770 31 Architecture of a Typical Data Mining System Graphical user interface Pattern evaluation Data mining engine Knowledge-base Database or data warehouse server Data cleaning & data integration Filtering Data Warehouse Databases CAP 4770 32 Data Mining: On What Kind of Data? • • • • Relational databases Data warehouses Transactional databases Advanced DB and information repositories – – – – – – Object-oriented and object-relational databases Spatial databases Time-series data and temporal data Text databases and multimedia databases Heterogeneous and legacy databases WWW CAP 4770 33 What Can Data Mining Do? • Cluster • Classify – Categorical, Regression • Semi-supervised • Summarize – Summary statistics, Summary rules • Link Analysis / Model Dependencies – Association rules • Sequence analysis – Time-series analysis, Sequential associations • Detect Deviations CAP 4770 34 Data Mining Tasks • Prediction Methods – Use some variables to predict unknown or future values of other variables. • Description Methods – Find human-interpretable patterns that describe the data. From [Fayyad, et.al.] Advances in Knowledge Discovery and Data Mining, 1996 CAP 4770 35 Data Mining Tasks... • • • • • • Classification [Predictive] Clustering [Descriptive] Association Rule Discovery [Descriptive] Sequential Pattern Discovery [Descriptive] Regression [Predictive] Deviation Detection [Predictive] CAP 4770 36 Classification Example Tid Refund Marital Status Taxable Income Cheat Refund Marital Status Taxable Income Cheat 1 Yes Single 125K No No Single 75K ? 2 No Married 100K No Yes Married 50K ? 3 No Single 70K No No Married 150K ? 4 Yes Married 120K No Yes Divorced 90K ? 5 No Divorced 95K Yes No Single 40K ? 6 No Married No No Married 80K ? 60K 10 7 Yes Divorced 220K No 8 No Single 85K Yes 9 No Married 75K No 10 10 No Single 90K Yes Training Set CAP 4770 Learn Classifier Test Set Model 37 Classification: Definition • Given a collection of records (training set ) – Each record contains a set of attributes, one of the attributes is the class. • Find a model for class attribute as a function of the values of other attributes. • Goal: previously unseen records should be assigned a class as accurately as possible. – A test set is used to determine the accuracy of the model. Usually, the given data set is divided into training and test sets, with training set used to build the model and test set used to validate it. CAP 4770 38 Classification: Application 1 • Direct Marketing – Goal: Reduce cost of mailing by targeting a set of consumers likely to buy a new cell-phone product. – Approach: • Use the data for a similar product introduced before. • We know which customers decided to buy and which decided otherwise. This {buy, don’t buy} decision forms the class attribute. • Collect various demographic, lifestyle, and companyinteraction related information about all such customers. – Type of business, where they stay, how much they earn, etc. • Use this information as input attributes to learn a classifier model. From [Berry & Linoff] Data Mining Techniques, 1997 CAP 4770 39 Classification: Application 2 • Fraud Detection – Goal: Predict fraudulent cases in credit card transactions. – Approach: • Use credit card transactions and the information on its account-holder as attributes. – When does a customer buy, what does he buy, how often he pays on time, etc • Label past transactions as fraud or fair transactions. This forms the class attribute. • Learn a model for the class of the transactions. • Use this model to detect fraud by observing credit card transactions on an account. CAP 4770 40 Classification: Application 3 • Customer Attrition/Churn: – Goal: To predict whether a customer is likely to be lost to a competitor. – Approach: • Use detailed record of transactions with each of the past and present customers, to find attributes. – How often the customer calls, where he calls, what timeof-the day he calls most, his financial status, marital status, etc. • Label the customers as loyal or disloyal. • Find a model for loyalty. From [Berry & Linoff] Data Mining Techniques, 1997 CAP 4770 41 Classification: Application 4 • Sky Survey Cataloging – Goal: To predict class (star or galaxy) of sky objects, especially visually faint ones, based on the telescopic survey images (from Palomar Observatory). – 3000 images with 23,040 x 23,040 pixels per image. – Approach: • • • • Segment the image. Measure image attributes (features) - 40 of them per object. Model the class based on these features. Success Story: Could find 16 new high red-shift quasars, some of the farthest objects that are difficult to find! From [Fayyad, et.al.] Advances in Knowledge Discovery and Data Mining, 1996 CAP 4770 42 Clustering Definition • Given a set of data points, each having a set of attributes, and a similarity measure among them, find clusters such that – Data points in one cluster are more similar to one another. – Data points in separate clusters are less similar to one another. • Similarity Measures: – Euclidean Distance if attributes are continuous. – Other Problem-specific Measures. CAP 4770 43 Illustrating Clustering Euclidean Distance Based Clustering in 3-D space. Intracluster distances are minimized Intercluster distances are maximized CAP 4770 44 Clustering: Application 1 • Market Segmentation: – Goal: subdivide a market into distinct subsets of customers where any subset may conceivably be selected as a market target to be reached with a distinct marketing mix. – Approach: • Collect different attributes of customers based on their geographical and lifestyle related information. • Find clusters of similar customers. • Measure the clustering quality by observing buying patterns of customers in same cluster vs. those from different clusters. CAP 4770 45 Clustering: Application 2 • Document Clustering: – Goal: To find groups of documents that are similar to each other based on the important terms appearing in them. – Approach: To identify frequently occurring terms in each document. Form a similarity measure based on the frequencies of different terms. Use it to cluster. – Gain: Information Retrieval can utilize the clusters to relate a new document or search CAP 4770 46 term to clustered documents. Clustering of S&P 500 Stock Data Observe Stock Movements every day. Clustering points: Stock-{UP/DOWN} Similarity Measure: Two points are more similar if the events described by them frequently happen together on the same day. We used association rules to quantify a similarity measure. Discovered Clusters 1 2 3 4 Applied-Matl-DOW N,Bay-Net work-Down,3-COM-DOWN, Cabletron-Sys-DOWN,CISCO-DOWN,HP-DOWN, DSC-Co mm-DOW N,INTEL-DOWN,LSI-Logic-DOWN, Micron-Tech-DOWN,Texas-Inst-Down,Tellabs-Inc-Down, Natl-Semiconduct-DOWN,Oracl-DOWN,SGI-DOW N, Sun-DOW N Apple-Co mp-DOW N,Autodesk-DOWN,DEC-DOWN, ADV-M icro-Device-DOWN,Andrew-Corp-DOWN, Co mputer-Assoc-DOWN,Circuit-City-DOWN, Co mpaq-DOWN, EM C-Corp-DOWN, Gen-Inst-DOWN, Motorola-DOW N,Microsoft-DOWN,Scientific-Atl-DOWN Fannie-Mae-DOWN,Fed-Ho me-Loan-DOW N, MBNA-Corp -DOWN,Morgan-Stanley-DOWN Baker-Hughes-UP,Dresser-Inds-UP,Halliburton-HLD-UP, Louisiana-Land-UP,Phillips-Petro-UP,Unocal-UP, Schlu mberger-UP CAP 4770 Industry Group Technology1-DOWN Technology2-DOWN Financial-DOWN Oil-UP 47 Association Rule Discovery: Definition • Given a set of records each of which contain some number of items from a given collection; TID 1 2 3 4 5 – Produce dependency rules which will predict occurrence of an item based on occurrences of other Items items. Bread, Coke, Milk Beer, Bread Beer, Coke, Diaper, Milk Beer, Bread, Diaper, Milk Coke, Diaper, Milk Rules Discovered: {Milk} --> {Coke} {Diaper, Milk} --> {Beer} CAP 4770 48 Association Rule Discovery: Application 1 • Marketing and Sales Promotion: – Let the rule discovered be {Bagels, … } --> {Potato Chips} – Potato Chips as consequent => Can be used to determine what should be done to boost its sales. – Bagels in the antecedent => Can be used to see which products would be affected if the store discontinues selling bagels. – Bagels in antecedent and Potato chips in consequent => Can be used to see what products should be sold with Bagels to promote sale of Potato chips! CAP 4770 49 Association Rule Discovery: Application 2 • Supermarket shelf management. – Goal: To identify items that are bought together by sufficiently many customers. – Approach: Process the point-of-sale data collected with barcode scanners to find dependencies among items. – A classic rule -• If a customer buys diaper and milk, then he is very likely to buy beer. • So, don’t be surprised if you find six-packs stacked next to diapers! CAP 4770 50 Association Rule Discovery: Application 3 • Inventory Management: – Goal: A consumer appliance repair company wants to anticipate the nature of repairs on its consumer products and keep the service vehicles equipped with right parts to reduce on number of visits to consumer households. – Approach: Process the data on tools and parts required in previous repairs at different consumer locations and discover the co-occurrence patterns. CAP 4770 51 Sequential Pattern Discovery: Definition • Given is a set of objects, with each object associated with its own timeline of events, find rules that predict strong sequential dependencies among different events. (A B) (C) (D E) • Rules are formed by first disovering patterns. Event occurrences in the patterns are governed by timing constraints. (A B) <= xg (C) (D E) >ng <= ws <= ms CAP 4770 52 Sequential Pattern Discovery: Examples • In telecommunications alarm logs, – (Inverter_Problem Excessive_Line_Current) (Rectifier_Alarm) --> (Fire_Alarm) • In point-of-sale transaction sequences, – Computer Bookstore: (Intro_To_Visual_C) (C++_Primer) --> (Perl_for_dummies,Tcl_Tk) – Athletic Apparel Store: (Shoes) (Racket, Racketball) --> (Sports_Jacket) CAP 4770 53 Regression • Predict a value of a given continuous valued variable based on the values of other variables, assuming a linear or nonlinear model of dependency. • Greatly studied in statistics, neural network fields. • Examples: – Predicting sales amounts of new product based on advetising expenditure. – Predicting wind velocities as a function of temperature, humidity, air pressure, etc. – Time series prediction of stock market indices. CAP 4770 54 Deviation/Anomaly Detection • Detect significant deviations from normal behavior • Applications: – Credit Card Fraud Detection – Network Intrusion Detection Typical network traffic at University level may reach over 100 million connections per day CAP 4770 55 Are All the “Discovered” Patterns Interesting? • A data mining system/query may generate thousands of patterns, not all of them are interesting. – Suggested approach: Human-centered, query-based, focused mining • Interestingness measures: A pattern is interesting if it is easily understood by humans, valid on new or test data with some degree of certainty, potentially useful, novel, or validates some hypothesis that a user seeks to confirm – Objective vs. subjective interestingness measures: CAP 4770 57 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues CAP 4770 58 Multiple Disciplines Artificial Intelligence Machine Learning Database Management Statistics Visualization Algorithms Data Mining Information Retrieval Systems CAP 4770 59 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues CAP 4770 60 Data Mining: Classification Schemes • General functionality – Descriptive data mining – Predictive data mining • Different views, different classifications – Kinds of databases to be mined – Kinds of knowledge to be discovered – Kinds of techniques utilized – Kinds of applications adapted CAP 4770 61 Multi-Dimensional View of Data Mining • Data to be mined – Relational, data warehouse, transactional, stream, objectoriented/relational, active, spatial, time-series, text, multi-media, heterogeneous, legacy, WWW • Knowledge to be mined – Characterization, discrimination, association, classification, clustering, trend/deviation, outlier analysis, etc. – Multiple/integrated functions and mining at multiple levels • Techniques utilized – Database-oriented, data warehouse (OLAP), machine learning, statistics, visualization, etc. • Applications adapted – Retail, telecommunication, banking, fraud analysis, bio-data mining, stock market analysis, Web mining, etc. CAP 4770 62 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues CAP 4770 63 History of the Data Mining • Knowledge Discovery in Databases workshops started ‘89 – Now a conference under the auspices of ACM SIGKDD – IEEE conference series started 2001 • Key founders / technology contributors: – Usama Fayyad, JPL (then Microsoft, now has his own company, Digimine) – Gregory Piatetsky-Shapiro (then GTE, now his own data mining consulting company, Knowledge Stream Partners) – Rakesh Agrawal (IBM Research) The term “data mining” has been around since at least 1983 – as a pejorative term in the statistics community CAP 4770 64 Outline • Course Logistics • Data Mining Introduction • Four Key Characteristics – – – – Combination of Theory and Application Engineering Process Collection of Functionalities Interdisciplinary field • How do we categorize data mining systems? • History of Data Mining • Research Issues CAP 4770 66 Data Mining Complications • Volume of Data – Clever algorithms needed for reasonable performance • Interest measures – How do we ensure algorithms select “interesting” results? • “Knowledge Discovery Process” skill required – How to select tool, prepare data? • Data Quality – How do we interpret results in light of low quality data? • Data Source Heterogeneity – How do we combine data from multiple sources? CAP 4770 67 Research Issues • Mining methodology – Mining different kinds of knowledge from diverse data types, e.g., bio, stream, Web – Performance: efficiency, effectiveness, and scalability – Pattern evaluation: the interestingness problem – Incorporation of background knowledge – Handling noise and incomplete data – Parallel, distributed and incremental mining methods – Integration of the discovered knowledge with existing one: knowledge fusion • User interaction – Data mining query languages and ad-hoc mining – Expression and visualization of data mining results – Interactive mining of knowledge at multiple levels of abstraction • Applications and social impacts – Domain-specific data mining & invisible data mining – Protection of data security, integrity, and privacy CAP 4770 68