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Data Mining: Current Status and Research Directions. Jiawei Han Intelligent Database Systems Research Lab School of Computing Science Simon Fraser University, Canada http://www.cs.sfu.ca/~han. Outline. Why is data mining hot? Current status: Major technical progress
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Data Mining: Current Status and Research Directions Jiawei Han Intelligent Database Systems Research Lab School of Computing Science Simon Fraser University, Canada http://www.cs.sfu.ca/~han Data Mining: Status and Directions
Outline • Why is data mining hot? • Current status: Major technical progress • Is data mining flying high, or not? • How to fly data mining high?—Research directions on data mining Data Mining: Status and Directions
Why Is Data Mining Hot? • Data mining (knowledge discovery in databases) • Extraction of interesting (non-trivial,implicit, previously unknown and potentially useful) information (knowledge) or patterns from data in large databases or other information repositories • Necessity is the mother of invention • Data is everywhere—data mining should be everywhere, too! • Understand and use data—an imminent task! Data Mining: Status and Directions
Data, Data, Everywhere!! • Relational database—A commodity of every enterprise • Huge data warehouses are under construction • POS (Point of Sales): Transactional DBs in terabytes • Object-relational databases, distributed, heterogeneous, and legacy databases • Spatial databases (GIS), remote sensing database (EOS), and scientific/engineering databases • Time-series data (e.g., stock trading) and temporal data • Text (documents, emails) and multimedia databases • WWW: A huge, hyper-linked, dynamic, global information system Data Mining: Status and Directions
Data Mining Is Everywhere, too!—A Multi-Dimensional View of Data Mining • Databases to be mined • Relational, transactional, object-relational, active, spatial, time-series, text, multi-media, heterogeneous, legacy, WWW, etc. • Knowledge to be mined • Characterization, discrimination, association, classification, clustering, trend, deviation and outlier analysis, etc. • Techniques utilized • Database-oriented, data warehouse (OLAP), machine learning, statistics, visualization, neural network, etc. • Applications adapted • Retail, telecommunication, banking, fraud analysis, DNA mining, stock market analysis, Web mining, Weblog analysis, etc. Data Mining: Status and Directions
Data Mining: Confluence of Multiple Disciplines Database Technology Statistics Data Mining Machine Learning (AI) Visualization Information Science Other Disciplines Data Mining: Status and Directions
Data Mining—One Can Trace Back to Early Civilization • Most scientific discoveries involve “data mining” • Kepler’s Law, Newton’s Laws, periodic table of chemical elements, …, from “big bang” to DNA • Statistics: A discipline dedicated to data analysis • Then why data mining? What are the differences? • Huge amount of data—in giga to tera bytes • Fast computer—quick response, interactive analysis • Multi-dimensional, powerful, thorough analysis • High-level, “declarative”—user’s ease and control • Automated or semi-automated—mining functions hidden or built-in in many systems Data Mining: Status and Directions
A Brief History of Data Mining Activities • 1989 IJCAI Workshop on Knowledge Discovery in Databases • Knowledge Discovery in Databases (G. Piatetsky-Shapiro and W. Frawley, 1991) • 1991-1994 Workshops on Knowledge Discovery in Databases • Advances in Knowledge Discovery and Data Mining (U. Fayyad, G. Piatetsky-Shapiro, P. Smyth, and R. Uthurusamy, 1996) • 1995-1998 International Conferences on Knowledge Discovery in Databases and Data Mining (KDD’95-98) • Journal of Data Mining and Knowledge Discovery (1997) • 1998 ACM SIGKDD, SIGKDD’1999-2001 conferences, and SIGKDD Explorations • More conferences on data mining • PAKDD, PKDD, SIAM-Data Mining, (IEEE) ICDM, DaWaK, SPIE-DM, etc. Data Mining: Status and Directions
Research Progress in the Last Decade • Multi-dimensional data analysis: Data warehouse and OLAP (on-line analytical processing) • Association, correlation, and causality analysis • Classification: scalability and new approaches • Clustering and outlier analysis • Sequential patterns and time-series analysis • Similarity analysis: curves, trends, images, texts, etc. • Text mining, Web mining and Weblog analysis • Spatial, multimedia, scientific data analysis • Data preprocessing and database compression • Data visualization and visual data mining • Many others, e.g., collaborative filtering Data Mining: Status and Directions
Multi-Dimensional Data Analysis • Data warehousing: integration from heterogeneous or semi-structured databases • Multi-dimensional modeling of data: star & snowflake schemas • Efficient and scalable computation of data cubes or iceberg cubes • OLAP (on-line analytical processing): drilling, dicing, slicing, etc. • Discovery-driven exploration of data cubes • From OLAP to OLAM: A multi-dimensional view for on-line analytical mining Data Mining: Status and Directions
Association and Frequent Pattern Analysis • Efficient mining of frequent patterns and association rules: • Apriori and FP-growth algorithms • Multi-level, multi-dimensional, quantitative association mining • From association to correlation, sequential patterns, partial periodicity, cyclic rules, ratio rules, etc. • Query and constraint-based association analysis Data Mining: Status and Directions
Classification: Scalable Methods and Handling of Complex Types of Data • Classification has been an essential theme in machine learning, and statistics research • Decision trees, Bayesian classification, neural networks, k-nearest neighbors, etc. • Tree-pruning, Boosting, bagging techniques • Efficient and scalable classification methods • Exploration of attribute-class pairs • SLIQ, SPRINT, RainForest, BOAT, etc. • Classification of semi-structured and non-structured data • Classification by clustering association rules (ARCS) • Association-based classification • Web document classification Data Mining: Status and Directions
Clustering and Outlier Analysis • Partitioning methods • k-means, k-medoids, CLARANS • Hierarchical methods: micro-clusters • Birch, Cure, Chameleon • Density-based methods: • DBSCAN and OPTICS, DENCLU • Grid-based methods • STING, CLIQUE, WaveCluster • Outlier analysis: • statistics-based, distance-based, deviation-based • Constraint-based clustering • COD (Clustering with Obstructed Distance) • User-specified constraints Data Mining: Status and Directions
Sequential Patterns and Time-Series Analysis • Trend analysis • Trend movement vs. cyclic variations, seasonal variations and random fluctuations • Similarity search in time-series database • Handling gaps, scaling, etc. • Indexing methods and query languages for time-series • Sequential pattern mining • Various kinds of sequences, various methods • From GSP to PrefixSpan • Periodicity analysis • Full periodicity, partial periodicity, cyclic association rules Data Mining: Status and Directions
Similarity Search: Similar Curves, Trends, Images, and Texts • Various kinds of data, various similarity mining methods • Discovery of similar trends in time-series data • Data transformation & high-dimensional structures • Finding similar images based on color, texture, etc. • Content-based vs. keyword-based retrieval • Color histogram-based signature • Multi-feature composed signature • Finding documents with similar texts • Similar keywords (synonymy & polysemy) • Term frequency matrix • Latent semantic indexing Data Mining: Status and Directions
Spatial, Multimedia, Scientific Data Analysis • Multi-dimensional analysis of spatial, multimedia and scientific data • Geo-spatial data cube and spatial OLAP • The curse of dimensionality problem • Association analysis • A progressive refinement methodology • Micro-clustering can be used for preprocessing in the analysis of complex types of data • Classification • Association-based for handling high-dimensionality and sparse data Data Mining: Status and Directions
Data Mining Industry and Applications • From research prototypes to data mining products, languages, and standards • IBM Intelligent Miner, SAS Enterprise Miner, SGI MineSet, Clementine, MS/SQLServer 2000, DBMiner, BlueMartini, MineIt, DigiMine, etc. • A few data mining languages and standards (esp. MS OLEDB for Data Mining). • Application achievements in many domains • Market analysis, trend analysis, fraud detection, outlier analysis, Web mining, etc. Data Mining: Status and Directions
Is Data Mining Flying? Or Not?? • Data mining is flying • R & D have been striding forward greatly • Applications have been broadened substantially • But not as high as some may have hoped. Why not? • Hope to see billions of $’s within years? • A young and coming technology, not a hype! • Not bread-and-butter but value-added service • DBMS, WWW, and other information systems will still be a “data mining” aircraft-carrier • Not on-the-shelf in nature • Need training, understanding, and customizing (re-develop.) • Young technology—need much R&D to fly high • Much research, development, and real problem solving! Data Mining: Status and Directions
How to Fly Data Mining High?—Research Directions • Web mining • Towards integrated data mining environments and tools • “Vertical” (or application-specific) data mining • Invisible data mining • Towards intelligent, efficient, and scalable data mining methods Data Mining: Status and Directions
Web Mining: A Fast Expanding Frontier in Data Mining • Mine what Web search engine finds • Automatic classification of Web documents • Discovery of authoritative Web pages, Web structures and Web communities • Meta-Web Warehousing: Web yellow page service • Web usage mining Data Mining: Status and Directions
Mine What Web Search Engine Finds • Current Web search engines: A convenient source for mining • keyword-based, return too many, often low quality answers, still missing a lot, not customized, etc. • Data mining will help: • coverage: “Enlarge and then shrink,” using synonyms and conceptual hierarchies • better search primitives: user preferences/hints • linkage analysis: authoritative pages and clusters • Web-based languages: XML + WebSQL + WebML • customization: home page + Weblog + user profiles Data Mining: Status and Directions
Discovery of Authoritative Pages in WWW • Page-rank method ( Brin and Page, 1998): • Rank the "importance" of Web pages, based on a model of a "random browser." • Hub/authority method (Kleinberg, 1998): • Prominent authorities often do not endorse one another directly on the Web. • Hub pages have a large number of links to many relevant authorities. • Thus hubs and authorities exhibit a mutually reinforcing relationship: • Both the page-rank and hub/authority methodologies have been shown to provide qualitatively good search results for broad query topics on the WWW. Data Mining: Status and Directions
Automatic Classification of Web Documents • Web document classification: • Good human classification: Yahoo!, CS term hierarchies • These classifications can be used as training sets to build up learning model • Key-word based classification is different from multi-dimensional classification • Association or clustering-based classification is often more effective • Multi-level classification is important Data Mining: Status and Directions
A Multiple Layered Meta-Web Architecture More Generalized Descriptions Layern ... Generalized Descriptions Layer1 Layer0 Data Mining: Status and Directions
Web Yellow Page Service: A Multi-Layer, Meta-Web Approach • XML: facilitates structured and meta-information extraction • Automatic classification of Web documents: • based on Yahoo!, etc. as training set + keyword-based correlation/classification analysis (IR/AI assistance) • Automatic ranking of important Web pages • authoritative site recognition and clustering Web pages • Generalization-based multi-layer meta-Web construction • With the assistance of clustering and classification analysis • Meta-Web can be warehoused and incrementally updated • Querying and mining can be performed on or assisted by meta-Web Data Mining: Status and Directions
Importance of Constructing Multi-Layer Meta Web • Benefits of Multi-Layer Meta-Web: • Multi-dimensional Web info summary analysis • Approximate and intelligent query answering • Web high-level query answering (WebSQL, WebML) • Web content and structure mining • Observing the dynamics/evolution of the Web • Is it realistic to construct such a meta-Web? • It benefits even if it is partially constructed • The benefit may justify the cost of tool development, standardization, and partial restructuring Data Mining: Status and Directions
Web Usage (Click-Stream) Mining • Weblog provides rich information about Web dynamics • Multidimensional Weblog analysis: • disclose potential customers, users, markets, etc. • Plan mining (mining general Web accessing regularities): • Web linkage adjustment, performance improvements • Web accessing association/sequential pattern analysis: • Web cashing, prefetching, swapping • Trend analysis: • Dynamics of the Web: what has been changing? • Customized to individual users Data Mining: Status and Directions
Towards Integrated Data Mining Environments and Tools • OLAP Mining: Integration of Data Warehousing and Data Mining • Querying and Mining: An Integrated Information Analysis Environment • Basic Mining Operations and Mining Query Optimization • “Vertical” (or application-specific) data mining • Invisible data mining Data Mining: Status and Directions
OLAP Mining: An Integration of Data Mining and Data Warehousing • Data mining systems, DBMS, Data warehouse systems coupling • No coupling, loose-coupling, semi-tight-coupling, tight-coupling • On-line analytical mining data • integration of mining and OLAP technologies • Interactive mining multi-level knowledge • Necessity of mining knowledge and patterns at different levels of abstraction by drilling/rolling, pivoting, slicing/dicing, etc. • Integration of multiple mining functions • Characterized classification, first clustering and then association Data Mining: Status and Directions
An OLAM Architecture Mining query Mining result Layer4 User Interface User GUI API OLAM Engine OLAP Engine Layer3 OLAP/OLAM Data Cube API Layer2 MDDB MDDB Meta Data Database API Filtering&Integration Filtering Layer1 Data Repository Data cleaning Data Warehouse Databases Data integration Data Mining: Status and Directions
Querying and Mining: An Integrated Information Analysis Environment • Data mining as a component of DBMS, data warehouse, or Web information system • Integrated information processing environment • MS/SQLServer-2000 (Analysis service) • IBM IntelligentMiner on DB2 • SAS EnterpriseMiner: data warehousing + mining • Query-based mining • Querying database/DW/Web knowledge • Efficiency and flexibility: preprocessing, on-line processing, optimization, integration, etc. Data Mining: Status and Directions
Basic Mining Operations and Mining Query Optimization • Relational databases: There are a set of basic relational operations and a standard query language, SQL • E.g., selection, projection, join, set difference, intersection, Cartesian product, etc. • Are there a set of standard data mining operations, on which optimizations can be done? • Difficulty: different definitions on operations • Importance: optimization can be performed on them systematically, standardization to facilitate information exchange and system interoperability Data Mining: Status and Directions
“Vertical” Data Mining • Generic data mining tools? —Too simple to match domain-specific, sophisticated applications • Expert knowledge and business logic represent many years of work in their own fields! • Data mining + business logic + domain experts • A multi-dimensional view of data miners • Complexity of data: Web, sequence, spatial, multimedia, … • Complexity of domains: DNA, astronomy, market, telecom, … • Domain-specific data mining tools • Provide concrete, killer solution to specific problems • Feedback to build more powerful tools Data Mining: Status and Directions
Invisible Data Mining • Build mining functions into daily information services • Web search engine (link analysis, authoritative pages, user profiles)—adaptive web sites, etc. • Improvement of query processing: history + data • Making service smart and efficient • Benefits from/to data mining research • Data mining research has produced many scalable, efficient, novel mining solutions • Applications feed new challenge problems to research Data Mining: Status and Directions
Towards Intelligent Tools for Data Mining • Integration paves the way to intelligent mining • Smart interface brings intelligence • Easy to use, understand and manipulate • One picture may worth 1,000 words • Visual and audio data mining • Human-Centered Data Mining • Towards self-tuning, self-managing, self-triggering data mining Data Mining: Status and Directions
Integrated Mining: A Booster for Intelligent Mining • Integration paves the way to intelligent mining • Data mining integrates with DBMS, DW, WebDB, etc • Integration inherits the power of up-to-date information technology: querying, MD analysis, similarity search, etc. • Mining can be viewed as querying database knowledge • Integration leads to standard interface/language, function/process standardization, utility, and reachability • Efficiency and scalability bring intelligent mining to reality Data Mining: Status and Directions
One Picture May Worth 1000 Words! • Visual Data Mining • Visualization of data • Visualization of data mining results • Visualization of data mining processes • Interactive data mining: visual classification • One melody may worth 1000 words too! • Audio data mining: turn data into music and melody! • Uses audio signals to indicate the patterns of data or the features of data mining results Data Mining: Status and Directions
Visualization of data mining results in SAS Enterprise Miner:scatter plots Data Mining: Status and Directions
Visualization of association rules in MineSet 3.0 Data Mining: Status and Directions
Visualization of adecision treein MineSet 3.0 Data Mining: Status and Directions
Visualization of Data Mining Processes by Clementine Data Mining: Status and Directions
Interactive Visual Mining by Perception-Based Classification (PBC) Data Mining: Status and Directions
Human-Centered Data Mining • Finding all the patterns autonomously in a database? — unrealistic because the patterns could be too many but uninteresting • Data mining should be an interactive process • User directs what to be mined • Users must be provided with a set of primitivesto be used to communicate with the data mining system — using a data mining query language • User should provide constraints on what to be mined • System should use such constraints to guide the mining process (constraint-based mining or mining query optimization) Data Mining: Status and Directions
Constraint-Based Mining • What kinds of constraints can be used in mining? • Knowledge type constraint: classification, association, etc. • Data constraint: SQL-like queries • Find products sold together in Vancouver in Feb.’01. • Dimension/level constraints: • in relevance to region, price, brand, customer category. • Rule constraints: • small sales (price < $10) triggers big sales (sum > $200). • Interestingness constraints: • E.g., strong rules (min_support 3%, min_confidence 60%, min_lift > 3.0). Data Mining: Status and Directions
Rule Constraints: A Classification Succinctness Anti-monotonicity Monotonicity Convertible constraints Inconvertible constraints Data Mining: Status and Directions
Constraint-Based Clustering Analysis • User-specified constraints: no cluster has less than 1000 gold customers • Resource allocation (clustering) with obstacles Data Mining: Status and Directions
Towards Automated Data Mining? • It is not realistic to automatically find all the knowledge in a large database • Thus we promote human-centered, constraint-based mining • However, to achieve genuine intelligent data mining, data mining process should be self-tuning, self-managing, self-triggering • Functions should be developed to achieve such performance Data Mining: Status and Directions
Conclusions • Data mining—A promising research frontier • Data mining research has been striding forward greatly in the last decade • However, data mining, as an industry, has not been flying as high as expected • Much research and application exploration are needed • Web mining • Towards integrated data mining environments and tools • Towards intelligent, efficient, and scalable data mining methods Data Mining: Status and Directions
http://www.cs.sfu.ca/~han http://db.cs.sfu.ca Thank you !!! Data Mining: Status and Directions
References • J. Han and M. Kamber, Data Mining: Concepts and Techniques, Morgan Kaufmann, 2001. • J. Han, L. V. S. Lakshmanan, and R. T. Ng, "Constraint-Based, Multidimensional Data Mining", COMPUTER (special issues on Data Mining), 32(8): 46-50, 1999. Data Mining: Status and Directions