Chapter 9 - Data Analysis

1. Chapter 9 - Data Analysis Presented by, Professor, Hair Priya Pucchakayala Dr. T. Y. Lin & Donavon Norwood

2. 2 Outline • What is Data Analysis? • Why data should be analyzed? • What is a Decision Table? • Condition/Decision attributes of the Stoker table • Analyzing Inconsistent data in the Stoker table • Analyzing Consistent data in the Stoker table • Conclusion

3. Data Analysis • Data Analysis is a process of gathering, modelling and transforming data with a goal of highlighting useful information, suggesting conclusions, and supporting decision making. • Data Analysis is the process of systematically applying statistical and/or logical techniques to describe and illustrate, condense and recap, and evaluate data. Ways to analyze data • Compare constantly • Categorize and sort

4. Why data should be analyzed? • Data Mining is a particular data analysis technique that focuses on modeling and knowledge discovery for predictive rather than purely descriptive purposes. • Data analysis does NOT explain but it does summarize and provide organization to data. • It tries to make sense of these rows and columns in the decision tables.

5. 5 Decision Table • According to Wiki enclycopedia a decision table are a precise yet compact way to model complicated logic. • Decision tables, like if-then-else and switch-case statements, associate conditions with actions to perform. • The structure of Decision tables are typically divided into four quadrants, as shown below: The four quadrants • Each decision corresponds to a variable, relation or predicate whose possible values are listed among the condition alternatives. • Each action is a procedure or operation to perform, and the entries specify whether (or in what order) the action is to be performed for the set of condition alternatives the entry corresponds to. • In this presentation we will use the Stoker decision table as the example of a decision table.

6. 6 Decision Table as Protocol of Observations • We will analyze the stoker’s decisions while controlling the clinker kiln • Aim of the stoker is to keep the kiln in a “proper” state • Actions of the stoker can be described by a “Decision Table”

7. 7 Condition/Decision attributes of the Stoker table • Actions of the stoker can be described by a decision table, where • Burning zone temperature(BZT) • Burning zone color(BZC) Condition • Clinker granulation(CG) attributes • Kiln inside color(KIC) • Kiln revolutions(KR) Decision • Coal worm revolutions(CWR) attributes

8. 8 • The table describes action undertaken by a stoker, during one shift, when specific conditions observed by the stoker have been fulfilled numbers given in the column TIME are in fact ID labels of moments of time when the decision took place, and form the “universe” of the decision table. • Since many decisions are the same, hence identical decision rules can be removed • It can be described by table shown below,

9. 9 Decision Table 1 with Condition Attributes and Decision Attributes

10. 10 Derivation of Control Algorithms from Observation • Consistency of the stoker’s knowledge • The reduction of his knowledge and control algorithm generation from the observed stoker’s behavior

11. 11 Table 2: Removing attribute ‘a’ from the table1

12. 12 Table 4: Removing attribute ‘c’ from table1

13. 13 Table 5: Removing attribute ‘d’ from table1

14. 14 Table 3: Removing attribute ‘b’ from table1

15. 15 Table 6: After removing superfluous attribute ‘b’ & duplicate rules

16. 16 For e.g. let us compute core values and reduct values for the first decision rule: a3c2d2 ==> e2f4 In the table 7, values ‘a’ and ‘d’ are indispensible in the rule Since the following pairs of rules are Inconsistent. c2d2 ==> e2f4 (rule 1) c2d2 ==> e1f4 (rule 4) a3c2 ==> e2f4 (rule 1) a3c2 ==> e1f3 (rule 5) Thus a3 and d2 are core values of the decision value a3c2d2 ---> e2f4

17. 17 Table 6: Inconsitent rows without column a

18. 18 Table 6: Inconsitent rows without column c

19. 19 Table 6: Inconsitent rows without column d

20. 20 Conclusion • We determined that condition attributes a,c,anddwere core attributes to the Stoker table because when they were removed respectively from the Stoker table, the Stoker table contained inconsistent rows; • We then determined that condition attribute bwas a reduct or superfluous attribute of the Stoker table, because when it was removed from the Stoker table the table still contained consistent rows. • From there we were able to build our final Stoker decision table and algorithms.

21. 21 Thank you