Algorithms for Big Data. Dr. Jianye HAO Associate Professor School of Software Tianjin University

Transcription

1 Algorithms for Big Data Dr. Jianye HAO Associate Professor School of Software Tianjin University

2 Lecturer Jianye HAO ( 郝建业 ) Associate Professor at School of Software, Tianjin University Office: 55-A319 jianye.hao@tju.edu.cn Webpage:

3 Lecture Hours Lectures: Fri 1:30 5:00pm, Room 55-A210 Office hours: Wed 3:00-5:00 pm, Room 55-A319

4 Reference Books Leskovec, Rajaraman, and Ullman. Mining of Massive Datasets. Cambridge University Tan, Steinbach and Kumar. Introduction to Data Mining, Addison Welsey, 2006 Friedman J, Hastie T, Tibshirani R. The elements of statistical learning. Springer, Berlin: Springer series in statistics, 2001.

5 Course Objective To provide a fundamental understanding of basic data mining techniques for big data To discuss the strength and weakness of different techniques To Introduce the whole big data mining process To present some application of big data mining techniques to realworld and research problems.

6 Course Contents Content Classification I - Linear classifier, Naive Bayes, k-nn Classification II - Trees Data Governance Descriptive models I - Association Rule Descriptive Modes II -Clustering Regression (linear, Logistic, Ridge) Course Project

7 Course Assessment Part I: Group Presentation(50%) Each person presents one topic at one lecture Part II Group Project (50%) Five persons per group Propose your own solution using data mining techniques to improve the current state of the art Write a technical Report (50%) Present your idea (20%) Presentation Date: Jan 9 th, 2016 (firm) Report Deadline: Jan 15 th, 2016 (tentative)

8 Course Assessment In the final project report you should include: 1. Title and Abstract 2. Introduction (background, motivation, contribution) 3. Related work 4. Negotiation framework and your proposed solution 5. Experimental results 6. Conclusion

9 Course Assessment In the final project presentation you should, 1. Introduce your motivation 2. Explain your negotiation framework 3. Explain your proposed solution 4. Show your experimental results 5. Conclusion

10 Course Assessment Project Grading Criteria Motivation Novelty Effectiveness/performance Work load Report Quality Presentation Quality

11 Honesty in Academic works Attention is drawn to university policy and regulation on honesty in academic works, and to the disciplinary guidelines and procedures applicable to any breaches of such policy and regulations. Details may be found at What action may cause Plagiarism? Claiming that somebody else s ideas or words are your own. Literature review: provide clear information about where you found the literature you are reviewing Never directly copy from somebody else s paper -> rephrase appropriately When you summarize somebody s work, you should properly credit him for his work. Project Do your project on your own. Discussion among groups are encouraged Sharing your project with other group is equally Plagiarism (will be marked ZERO).

12 Project Introduction Genius Negotiation Platform A negotiation environment for heterogeneous negotiation agents A set of negotiation problems (domains) A set of negotiation agents (strategies) A set of analytical tools to evaluate an agent s performance Webpage: User manual: Resources: egotiating_agents_competition_(anac)

13 Source of Big Data Data collected and stored at enormous speeds (GB/hour) Business transactions (purchase, exchange, banking, stock) Surveillance data (video and picture, sensors, cameras) Satellite sensing: telescopes scanning the skies Microarrays generating gene expression data Scientific data (human psychology, ocean/earth activities) Text reports and memos ( ) Medical and personal data Automated negotiation history data

14 Why Mine Big Data? Commercial Viewpoint Lots of data is being collected and warehoused Web data, e-commerce purchases at department/ grocery stores Bank/Credit Card transactions /searching records Computers have become cheaper and more powerful Competitive Pressure is Strong Provide better, customized services (e.g. in Customer Relationship Management) Provide targeted and cost-effective ads to potential customers.

15 Why Mine Big Data? Scientific Viewpoint Data mining may help scientists in classifying and segmenting data in Hypothesis Formation New insights obtaining

16 Mining Large Data Sets - Motivation There is often information hidden in the data that is not readily evident Human analysts may take weeks to discover useful information Much of the data is never analyzed at all 4,000,000 3,500,000 3,000,000 2,500,000 2,000,000 1,500,000 1,000, ,000 0 The Data Gap Total new disk (TB) since 1995 Number of analysts From: R. Grossman, C. Kamath, V. Kumar, Data Mining for Scientific and Engineering Applications

17 How to Mine Big Data? Traditionally known as Data Mining Many Definitions Non-trivial extraction of implicit, previously unknown and potentially useful information from data Exploration & analysis, by automatic or semi-automatic means, of large quantities of data in order to discover meaningful patterns

18 How to Mine Big Data? Algorithms for mining big data Descriptive methods: Classification algorithms Nearest neighbor, k nearest neighbor Decision tree classification Neural network Regression (linear, logistic) Support Vector Machine Predictive methods: Clustering algorithms K-means Bisecting K-means Self-organizing map Hierarchical clustering

19 What is (not) Data Mining? What is not Data Mining? Look up phone number in phone directory Query a Web search engine for information about Amazon What is Data Mining? Certain names are more prevalent in certain US locations (O Brien, O Rurke, O Reilly in Boston area) Group together similar documents returned by search engine according to their context (e.g. Amazon rainforest, Amazon.com,)

20 Origins of Data Mining Draws ideas from machine learning/ai, pattern recognition, statistics, and database systems Traditional Techniques may be unsuitable due to Enormity of data High dimensionality of data Heterogeneous, distributed nature of data Statistics/ AI Data Mining Machine Learning/ Pattern Recognition Database systems

21 Data Mining Tasks Prediction Methods Use some variables to predict unknown or future values of other variables. Classification, Regression Description Methods Find human-interpretable patterns that describe the data. Clustering, Association rule discovery From [Fayyad, et.al.] Advances in Knowledge Discovery and Data Mining, 1996

22 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.

23 10 Classification Example Refund Marital Status Taxable Income Cheat No Single 75K? Yes Married 50K? No Married 150K? Yes Divorced 90K? No Single 40K? No Married 80K? Test Set Training Set Learn Classifier Model

24 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 company-interaction 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

25 Classification Example Test Set Training Set Learn Classifier Model

26 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.

27 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 time-of-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

28 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) 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

29 Classifying Galaxies Early Class: Stages of Formation Intermediate Courtesy: Attributes: Image features, Characteristics of light waves received, etc. Late Data Size: 72 million stars, 20 million galaxies Object Catalog: 9 GB Image Database: 150 GB

30 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 (Jaccard, cosine or edit distance) An example of clustering

31 Illustrating Clustering Euclidean Distance Based Clustering in 3-D space. Intracluster distances are minimized Intercluster distances are maximized

32 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 the same cluster vs. those from different clusters.

33 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 term to clustered documents.

34 Illustrating Document Clustering Clustering Points: 3204 Articles of Los Angeles Times. Similarity Measure: How many words are common in these documents (after some word filtering). Category Total Correctly Articles Placed Financial Foreign National Metro Sports Entertainment

35 Association Rule Discovery: Definition Given a set of records each of which contain some number of items from a given collection; Produce dependency rules which will predict occurrence of an item based on occurrences of other items. TID Items 1 Bread, Coke, Milk 2 Beer, Bread 3 Beer, Coke, Diaper, Milk 4 Beer, Bread, Diaper, Milk 5 Coke, Diaper, Milk Rules Discovered: {Milk} --> {Coke} {Diaper, Milk} --> {Beer} Market Basket Analysis Example

36 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!

37 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!

38 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: collect the data on tools and parts required in previous repairs at different consumer locations and discover the cooccurrence patterns.

39 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.

40 Deviation/Anomaly Detection Detect significant deviations from normal behavior Applications: Credit Card Fraud Detection Network Intrusion Detection

41 Automated Negotiation A negotiation consists of A number of agents (agent space) A negotiation domain D (outcome space) D = {I1, I2, In} and each issue consists of k values Ii = {v1,v2, vk} A number of utility space (preference profiles) A Laptop negotiation domain Two negotiation agents: agent A and agent B Three issues: brand, hard disk, monitor Each issue contains a number of discrete values One bidding instance is a Dell laptop with 80 Gb and 17 inch monitor.

42 Automated Negotiation Utility Space Specify a preference of each agent for each outcome Pareto optimal bids The optimal bid of an agent is the bid that gives the maximum utility to that agent The utilities of negotiation agents are often contradictory, i.e., one agent s gain is another agent s pain

43 Automated Negotiation Optimal goal of a negotiation Maximizing individual payoff Maximizing social welfare (the sum of the payoffs of all partied involved in the negotiation)

44 Automated Negotiation Negotiation protocol Defines the rules to regulate how the negotiation proceeds between negotiation agents. Agents are obliged to follow the protocol, and any deviation from the protocol will be penalized. Negotiation Strategy Specify how an agent should behave during a negotiation under the regulation of a negotiation protocol.

45 Negotiation Protocol Bilateral Negotiation Protocol (Alternating Offer Protocol) Involves two parties- agent A and B Agent A starts the negotiation first Each agent takes turn to negotiate Each agent is allowed to present one of the following three options Accept accept the current proposal from the negotiation partner Offer propose a new offer to the partner EndNegotiation choose to terminate the negotiation without reaching an agreement Reservation Value The value that an agent obtains if no agreement is reached by the end of negotiation Time pressure The utility decreases with the passing of negotiation time

46 Overall Structure of a Negotiation Strategy Decoupling Negotiating Agents to Explore the Space of Negotiation Strategies, Novel Insights in Agent-based Complex Automated Negotiation,2014

47 Negotiation Strategy Time-dependent Strategy Vary negotiation behavior with respect to the passage of time Concede more rapidly as the deadline approaches Boulware strategy The initial offer is maintained till time is almost exhausted, when the agent concedes up to its reservation value. Conceder strategy The agent goes to its reservation value quickly

48 Example: Boulware v.s. Conceder Consider a negotiation between a buyer and a seller

49 Negotiation Strategy Resource-dependent Strategy Concede more as resources becomes scare Remaining bandwidth to be allocated, money, etc. Behavior-dependent strategy Imitate the opponent s behavior Relative Tit-For-Tat: imitate in percentage terms Random absolute Tit-For-Tat: imitate in absolute terms with random behavior Averaged Tit-For-Tat: imitate in average percentage of changes in a window of history

50 Design Effective Negotiation Strategies using Mining Techniques Benefits of predicting the opponent s behavior Cooperative environments ->better coordination with others Competitive environments -> opportunity of taking exploitative actions to maximize its own payoff. How to predict the opponent s behavior? Neural Network [Predicting Opponent s Moves in Electronic Negotiations Using Neural Networks, Group Decision and Negotiation Conference,2006] Regression techniques (non-linear regression, Guassian process regression) - predicting the opponent s concession degree [Using gaussian processes to optimise concession in complex negotiations against unknown opponents, IJCAI, 2011] Chebychev Polynomials predict the opponent s decision function [Modeling opponent decision in repeated one-shot negotiations. Proceedings of the fourth international joint conference on Autonomous agents and multiagent systems. ACM, 2005: ]

51 Design Effective Negotiation Strategies using Mining Techniques Benefits of predicting the opponent s preference Increase the chance of reaching win-win negotiation outcomes Better understanding of the opponent s behaviors How to predict the opponent s preference? Bayesian Learning - Predict the opponent s issue weight and the evaluation function [Opponent modelling in automated multiissue negotiation using bayesian learning, AAMAS, 2008] Bayesian Learning predict the opponent s reservation value [Sycara K, Zeng D. Benefits of learning in negotiation, AAAI ]

52 Select Effective Negotiation Strategies using Mining Techniques Given a new domain, predicting which existing negotiation strategy performs best? Artificial Neural Network Decision Tree Linear/Logistic Regression

53 Run Genuis Download genius: Setting your java environment variables Create JAVA_HOME : C:\Program Files\Java\jdk1.7.0 Create CLASSPATH :.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar; Add PATH : %JAVA_HOME%\bin;%JAVA_HOME%\jre\bin; Run Genuis: java jar negosimulator.jar