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Frequent Pattern Mining��(Advanced)

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Research on Pattern Mining: A Road Map

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
    • Mining Multi-Level Association
    • Mining Multi-Dimensional Association
    • Mining Quantitative Association Rules
    • Mining Rare Patterns and Negative Patterns
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Mining Multiple-Level Association Rules

  • Items often form hierarchies
  • Flexible support settings
    • Items at the lower level are expected to have lower support
  • Exploration of shared multi-level mining (Agrawal & Srikant@VLB’95, Han & Fu@VLDB’95)

5

uniform support

Milk

[support = 10%]

2% Milk

[support = 6%]

Skim Milk

[support = 4%]

Level 1

min_sup = 5%

Level 2

min_sup = 5%

Level 1

min_sup = 5%

Level 2

min_sup = 3%

reduced support

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Multi-level Association: Flexible Support and Redundancy filtering

  • Flexible min-support thresholds: Some items are more valuable but less frequent
    • Use non-uniform, group-based min-support
    • E.g., {diamond, watch, camera}: 0.05%; {bread, milk}: 5%; …
  • Redundancy Filtering: Some rules may be redundant due to “ancestor” relationships between items
    • milk ⇒ wheat bread [support = 8%, confidence = 70%]
    • 2% milk ⇒ wheat bread [support = 2%, confidence = 72%]

The first rule is an ancestor of the second rule

  • A rule is redundant if its support is close to the “expected” value, based on the rule’s ancestor

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
    • Mining Multi-Level Association
    • Mining Multi-Dimensional Association
    • Mining Quantitative Association Rules
    • Mining Rare Patterns and Negative Patterns
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Mining Multi-Dimensional Association

  • Single-dimensional rules:

buys(X, “milk”) ⇒ buys(X, “bread”)

  • Multi-dimensional rules: ≥ 2 dimensions or predicates
    • Inter-dimension assoc. rules (no repeated predicates)

age(X,”19-25”) ∧ occupation(X,“student”) ⇒ buys(X, “coke”)

    • hybrid-dimension assoc. rules (repeated predicates)

age(X,”19-25”) ∧ buys(X, “popcorn”) ⇒ buys(X, “coke”)

  • Categorical Attributes: finite number of possible values, no ordering among values—data cube approach
  • Quantitative Attributes: Numeric, implicit ordering among values—discretization, clustering, and gradient approaches

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
    • Mining Multi-Level Association
    • Mining Multi-Dimensional Association
    • Mining Quantitative Association Rules
    • Mining Rare Patterns and Negative Patterns
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Mining Quantitative Associations

Techniques can be categorized by how numerical attributes, such as age or salary are treated

  1. Static discretization based on predefined concept hierarchies (data cube methods)
  2. Dynamic discretization based on data distribution (quantitative rules, e.g., Agrawal & Srikant@SIGMOD96)
  3. Clustering: Distance-based association (e.g., Yang & Miller@SIGMOD97)
    • One dimensional clustering then association
  4. Deviation: (such as Aumann and Lindell@KDD99)

Sex = female => Wage: mean=$7/hr (overall mean = $9)

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Static Discretization of Quantitative Attributes

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  • Discretized prior to mining using concept hierarchy.
  • Numeric values are replaced by ranges
  • In relational database, finding all frequent k-predicate sets will require k or k+1 table scans
  • Data cube is well suited for mining
  • The cells of an n-dimensional

cuboid correspond to the

predicate sets

  • Mining from data cubes�can be much faster

(income)

(age)

()

(buys)

(age, income)

(age,buys)

(income,buys)

(age,income,buys)

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Quantitative Association Rules Based on Statistical Inference Theory [Aumann and Lindell@DMKD’03]

  • Finding extraordinary and therefore interesting phenomena, e.g.,

(Sex = female) => Wage: mean=$7/hr (overall mean = $9)

    • LHS: a subset of the population
    • RHS: an extraordinary behavior of this subset
  • The rule is accepted only if a statistical test (e.g., Z-test) confirms the inference with high confidence
  • Subrule: highlights the extraordinary behavior of a subset of the pop. of the super rule
    • E.g., (Sex = female) ^ (South = yes) => mean wage = $6.3/hr
  • Two forms of rules
    • Categorical => quantitative rules, or Quantitative => quantitative rules
    • E.g., Education in [14-18] (yrs) => mean wage = $11.64/hr
  • Open problem: Efficient methods for LHS containing two or more quantitative attributes

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
    • Mining Multi-Level Association
    • Mining Multi-Dimensional Association
    • Mining Quantitative Association Rules
    • Mining Rare Patterns and Negative Patterns
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Negative and Rare Patterns

  • Rare patterns: Very low support but interesting
    • E.g., buying Rolex watches
    • Mining: Setting individual-based or special group-based support threshold for valuable items
  • Negative patterns
    • Since it is unlikely that one buys Ford Expedition (an SUV car) and Toyota Prius (a hybrid car) together, Ford Expedition and Toyota Prius are likely negatively correlated patterns
  • Negatively correlated patterns that are infrequent tend to be more interesting than those that are frequent

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Defining Negative Correlated Patterns (I)

  • Definition 1 (support-based)
    • If itemsets X and Y are both frequent but rarely occur together, i.e.,

sup(X U Y) < sup (X) * sup(Y)

    • Then X and Y are negatively correlated
  • Problem: A store sold two needle 100 packages A and B, only one transaction containing both A and B.
    • When there are in total 200 transactions, we have

s(A U B) = 0.005, s(A) * s(B) = 0.25, s(A U B) < s(A) * s(B)

    • When there are 105 transactions, we have

s(A U B) = 1/105, s(A) * s(B) = 1/103 * 1/103, s(A U B) > s(A) * s(B)

    • Where is the problem? —Null transactions, i.e., the support-based definition is not null-invariant!

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Defining Negative Correlated Patterns (II)

  • Definition 2 (negative itemset-based)
    • X is a negative itemset if (1) X = Ā U B, where B is a set of positive items, and Ā is a set of negative items, |Ā|≥ 1, and (2) s(X) ≥ μ
    • Itemsets X is negatively correlated, if

  • This definition suffers a similar null-invariant problem
  • Definition 3 (Kulzynski measure-based) If itemsets X and Y are frequent, but (P(X|Y) + P(Y|X))/2 < є, where є is a negative pattern threshold, then X and Y are negatively correlated.
  • Ex. For the same needle package problem, when no matter there are 200 or 105 transactions, if є = 0.01, we have

(P(A|B) + P(B|A))/2 = (0.01 + 0.01)/2 < є

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Constraint-based (Query-Directed) Mining

  • Finding all the patterns in a database autonomously? — unrealistic!
    • The patterns could be too many but not focused!
  • Data mining should be an interactive process
    • User directs what to be mined using a data mining query language (or a graphical user interface)
  • Constraint-based mining
    • User flexibility: provides constraints on what to be mined
    • Optimization: explores such constraints for efficient mining — constraint-based mining: constraint-pushing, similar to push selection first in DB query processing
    • Note: still find all the answers satisfying constraints, not finding some answers in “heuristic search”

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Constraints in Data Mining

  • Knowledge type constraint:
    • classification, association, etc.
  • Data constraint — using SQL-like queries
    • find product pairs sold together in stores in Chicago this year
  • Dimension/level constraint
    • in relevance to region, price, brand, customer category
  • Rule (or pattern) constraint
    • small sales (price < $10) triggers big sales (sum > $200)
  • Interestingness constraint
    • strong rules: min_support ≥ 3%, min_confidence ≥ 60%

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Meta-Rule Guided Mining

  • Meta-rule can be in the rule form with partially instantiated predicates and constants

P1(X, Y) ^ P2(X, W) => buys(X, “iPad”)

  • The resulting rule derived can be

age(X, “15-25”) ^ profession(X, “student”) => buys(X, “iPad”)

  • In general, it can be in the form of

P1 ^ P2 ^ … ^ Pl => Q1 ^ Q2 ^ … ^ Qr

  • Method to find meta-rules
    • Find frequent (l+r) predicates (based on min-support threshold)
    • Push constants deeply when possible into the mining process (see the remaining discussions on constraint-push techniques)
    • Use confidence, correlation, and other measures when possible

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Constraint-Based Frequent Pattern Mining

  • Pattern space pruning constraints
    • Anti-monotonic: If constraint c is violated, its further mining can be terminated
    • Monotonic: If c is satisfied, no need to check c again
    • Succinct: c must be satisfied, so one can start with the data sets satisfying c
    • Convertible: c is not monotonic nor anti-monotonic, but it can be converted into it if items in the transaction can be properly ordered
  • Data space pruning constraint
    • Data succinct: Data space can be pruned at the initial pattern mining process
    • Data anti-monotonic: If a transaction t does not satisfy c, t can be pruned from its further mining

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Pattern Space Pruning with Anti-Monotonicity Constraints

  • A constraint C is anti-monotone if the super pattern satisfies C, all of its sub-patterns do so too
  • In other words, anti-monotonicity: If an itemset S violates the constraint, so does any of its superset
  • Ex. 1. sum(S.price)v is anti-monotone
  • Ex. 2. range(S.profit) ≤ 15 is anti-monotone
    • Itemset ab violates C
    • So does every superset of ab
  • Ex. 3. sum(S.Price) v is not anti-monotone
  • Ex. 4. support count is anti-monotone: core property used in Apriori

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TID

Transaction

10

a, b, c, d, f

20

b, c, d, f, g, h

30

a, c, d, e, f

40

c, e, f, g

TDB (min_sup=2)

Item

Profit

a

40

b

0

c

-20

d

10

e

-30

f

30

g

20

h

-10

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Pattern Space Pruning with Monotonicity Constraints

  • A constraint C is monotone if the pattern satisfies C, we do not need to check C in subsequent mining
  • Alternatively, monotonicity: If an itemset S satisfies the constraint, so does any of its superset
  • Ex. 1. sum(S.Price)v is monotone
  • Ex. 2. min(S.Price) v is monotone
  • Ex. 3. C: range(S.profit) ≥ 15
    • Itemset ab satisfies C
    • So does every superset of ab

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TID

Transaction

10

a, b, c, d, f

20

b, c, d, f, g, h

30

a, c, d, e, f

40

c, e, f, g

TDB (min_sup=2)

Item

Profit

a

40

b

0

c

-20

d

10

e

-30

f

30

g

20

h

-10

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Data Space Pruning with Data Anti-monotonicity

  • A constraint c is data anti-monotone if for a pattern p cannot satisfy a transaction t under c, p’s superset cannot satisfy t under c either
  • The key for data anti-monotone is recursive data reduction
  • Ex. 1. sum(S.Price)v is data anti-monotone
  • Ex. 2. min(S.Price) v is data anti-monotone
  • Ex. 3. C: range(S.profit) ≥ 25 is data anti-monotone
    • Itemset {b, c}’s projected DB:
      • T10’: {d, f, h}, T20’: {d, f, g, h}, T30’: {d, f, g}
    • since C cannot satisfy T10’, T10’ can be pruned

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TID

Transaction

10

a, b, c, d, f, h

20

b, c, d, f, g, h

30

b, c, d, f, g

40

c, e, f, g

TDB (min_sup=2)

Item

Profit

a

40

b

0

c

-20

d

-15

e

-30

f

-10

g

20

h

-5

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Pattern Space Pruning with Succinctness

  • Succinctness:
    • Given A1, the set of items satisfying a succinctness constraint C, then any set S satisfying C is based on A1 , i.e., S contains a subset belonging to A1
    • Idea: Without looking at the transaction database, whether an itemset S satisfies constraint C can be determined based on the selection of items
    • min(S.Price) v is succinct
    • sum(S.Price) ≥ v is not succinct
  • Optimization: If C is succinct, C is pre-counting pushable

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Naïve Algorithm: Apriori + Constraint

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Database D

Scan D

C1

L1

L2

C2

C2

Scan D

C3

L3

Scan D

Constraint:

Sum{S.price} < 5

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Constrained Apriori : Push a Succinct Constraint Deep

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Database D

Scan D

C1

L1

L2

C2

C2

Scan D

C3

L3

Scan D

Constraint:

min{S.price } <= 1

not immediately

to be used

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Constrained FP-Growth: Push a Succinct Constraint Deep

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Constraint:

min{S.price } <= 1

Remove

infrequent

length 1

FP-Tree

1-Projected DB

No Need to project on 2, 3, or 5

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Constrained FP-Growth: Push a Data Anti-monotonic Constraint Deep

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Constraint:

min{S.price } <= 1

FP-Tree

Single branch, we are done

Remove from data

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Constrained FP-Growth: Push a Data Anti-monotonic Constraint Deep

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Constraint:

range{S.price } > 25

min_sup >= 2

FP-Tree

TID

Transaction

10

a, c, d, f, h

20

c, d, f, g, h

30

c, d, f, g

B-Projected DB

B

FP-Tree

TID

Transaction

10

a, b, c, d, f, h

20

b, c, d, f, g, h

30

b, c, d, f, g

40

a, c, e, f, g

TID

Transaction

10

a, b, c, d, f, h

20

b, c, d, f, g, h

30

b, c, d, f, g

40

a, c, e, f, g

Item

Profit

a

40

b

0

c

-20

d

-15

e

-30

f

-10

g

20

h

-5

Recursive

Data

Pruning

Single branch:

bcdfg: 2

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Convertible Constraints: Ordering Data in Transactions

  • Convert tough constraints into anti-monotone or monotone by properly ordering items
  • Examine C: avg(S.profit) 25
    • Order items in value-descending order
      • <a, f, g, d, b, h, c, e>
    • If an itemset afb violates C
      • So does afbh, afb*
      • It becomes anti-monotone!

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TID

Transaction

10

a, b, c, d, f

20

b, c, d, f, g, h

30

a, c, d, e, f

40

c, e, f, g

TDB (min_sup=2)

Item

Profit

a

40

b

0

c

-20

d

10

e

-30

f

30

g

20

h

-10

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Strongly Convertible Constraints

  • avg(X) 25 is convertible anti-monotone w.r.t. item value descending order R: <a, f, g, d, b, h, c, e>
    • If an itemset af violates a constraint C, so does every itemset with af as prefix, such as afd
  • avg(X) 25 is convertible monotone w.r.t. item value ascending order R-1: <e, c, h, b, d, g, f, a>
    • If an itemset d satisfies a constraint C, so does itemsets df and dfa, which having d as a prefix
  • Thus, avg(X) 25 is strongly convertible

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Item

Profit

a

40

b

0

c

-20

d

10

e

-30

f

30

g

20

h

-10

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Can Apriori Handle Convertible Constraints?

  • A convertible, not monotone nor anti-monotone nor succinct constraint cannot be pushed deep into the an Apriori mining algorithm
    • Within the level wise framework, no direct pruning based on the constraint can be made
    • Itemset df violates constraint C: avg(X) >= 25
    • Since adf satisfies C, Apriori needs df to assemble adf, df cannot be pruned
  • But it can be pushed into frequent-pattern growth framework!

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Item

Value

a

40

b

0

c

-20

d

10

e

-30

f

30

g

20

h

-10

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Pattern Space Pruning w. Convertible Constraints

  • C: avg(X) >= 25, min_sup=2
  • List items in every transaction in value descending order R: <a, f, g, d, b, h, c, e>
    • C is convertible anti-monotone w.r.t. R
  • Scan TDB once
    • remove infrequent items
      • Item h is dropped
    • Itemsets a and f are good, …
  • Projection-based mining
    • Imposing an appropriate order on item projection
    • Many tough constraints can be converted into (anti)-monotone

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TID

Transaction

10

a, f, d, b, c

20

f, g, d, b, c

30

a, f, d, c, e

40

f, g, h, c, e

TDB (min_sup=2)

Item

Value

a

40

f

30

g

20

d

10

b

0

h

-10

c

-20

e

-30

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Handling Multiple Constraints

  • Different constraints may require different or even conflicting item-ordering
  • If there exists an order R s.t. both C1 and C2 are convertible w.r.t. R, then there is no conflict between the two convertible constraints
  • If there exists conflict on order of items
    • Try to satisfy one constraint first
    • Then using the order for the other constraint to mine frequent itemsets in the corresponding projected database

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What Constraints Are Convertible?

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Constraint

Convertible anti-monotone

Convertible monotone

Strongly convertible

avg(S) , v

Yes

Yes

Yes

median(S) , v

Yes

Yes

Yes

sum(S) v (items could be of any value, v 0)

Yes

No

No

sum(S) v (items could be of any value, v 0)

No

Yes

No

sum(S) v (items could be of any value, v 0)

No

Yes

No

sum(S) v (items could be of any value, v 0)

Yes

No

No

……

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Constraint-Based Mining — A General Picture

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Constraint

Anti-monotone

Monotone

Succinct

v ∈ S

no

yes

yes

S ⊇ V

no

yes

yes

S ⊆ V

yes

no

yes

min(S) ≤ v

no

yes

yes

min(S) ≥ v

yes

no

yes

max(S) ≤ v

yes

no

yes

max(S) ≥ v

no

yes

yes

count(S) ≤ v

yes

no

weakly

count(S) ≥ v

no

yes

weakly

sum(S) ≤ v ( a ∈ S, a ≥ 0 )

yes

no

no

sum(S) ≥ v ( a ∈ S, a ≥ 0 )

no

yes

no

range(S) ≤ v

yes

no

no

range(S) ≥ v

no

yes

no

avg(S) θ v, θ ∈ { =, ≤, ≥ }

convertible

convertible

no

support(S) ≥ ξ

yes

no

no

support(S) ≤ ξ

no

yes

no

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Mining Colossal Frequent Patterns

  • F. Zhu, X. Yan, J. Han, P. S. Yu, and H. Cheng, “Mining Colossal Frequent Patterns by Core Pattern Fusion”, ICDE'07.
  • We have many algorithms, but can we mine large (i.e., colossal) patterns? ― such as just size around 50 to 100? Unfortunately, not!
  • Why not? ― the curse of “downward closure” of frequent patterns
    • The “downward closure” property
      • Any sub-pattern of a frequent pattern is frequent.
    • Example. If (a1, a2, …, a100) is frequent, then a1, a2, …, a100, (a1, a2), (a1, a3), …, (a1, a100), (a1, a2, a3), … are all frequent! There are about 2100 such frequent itemsets!
    • No matter using breadth-first search (e.g., Apriori) or depth-first search (FPgrowth), we have to examine so many patterns
  • Thus the downward closure property leads to explosion!

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Colossal Patterns: A Motivating Example

T1 = 1 2 3 4 ….. 39 40

T2 = 1 2 3 4 ….. 39 40

: .

: .

: .

: .

T40=1 2 3 4 ….. 39 40

40

Closed/maximal patterns may partially alleviate the problem but not really solve it: We often need to mine scattered large patterns!

Let the minimum support threshold σ= 20

There are frequent patterns of size 20

Each is closed and maximal

# patterns =

The size of the answer set is exponential to n

T1 = 2 3 4 ….. 39 40

T2 = 1 3 4 ….. 39 40

: .

: .

: .

: .

T40=1 2 3 4 …… 39

Then delete the items on the diagonal

Let’s make a set of 40 transactions

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Colossal Pattern Set: Small but Interesting

  • It is often the case that only a small number of patterns are colossal, i.e., of large size

  • Colossal patterns are usually attached with greater importance than those of small pattern sizes

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Mining Colossal Patterns: Motivation and Philosophy

  • Motivation: Many real-world tasks need mining colossal patterns
    • Micro-array analysis in bioinformatics (when support is low)
    • Biological sequence patterns
    • Biological/sociological/information graph pattern mining
  • No hope for completeness
    • If the mining of mid-sized patterns is explosive in size, there is no hope to find colossal patterns efficiently by insisting “complete set” mining philosophy
  • Jumping out of the swamp of the mid-sized results
    • What we may develop is a philosophy that may jump out of the swamp of mid-sized results that are explosive in size and jump to reach colossal patterns
  • Striving for mining almost complete colossal patterns
    • The key is to develop a mechanism that may quickly reach colossal patterns and discover most of them

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Alas, A Show of Colossal Pattern Mining!

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Let the min-support threshold σ= 20

Then there are closed/maximal frequent patterns of size 20

However, there is only one with size greater than 20, (i.e., colossal):

α= {41,42,…,79} of size 39

T1 = 2 3 4 ….. 39 40

T2 = 1 3 4 ….. 39 40

: .

: .

: .

: .

T40=1 2 3 4 …… 39

T41= 41 42 43 ….. 79

T42= 41 42 43 ….. 79

: .

: .

T60= 41 42 43 … 79

The existing fastest mining algorithms (e.g., FPClose, LCM) fail to complete running

Our algorithm outputs this colossal pattern in seconds

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Methodology of Pattern-Fusion Strategy

  • Pattern-Fusion traverses the tree in a bounded-breadth way
    • Always pushes down a frontier of a bounded-size candidate pool
    • Only a fixed number of patterns in the current candidate pool will be used as the starting nodes to go down in the pattern tree ― thus avoids the exponential search space
  • Pattern-Fusion identifies “shortcuts” whenever possible
    • Pattern growth is not performed by single-item addition but by leaps and bounded: agglomeration of multiple patterns in the pool
    • These shortcuts will direct the search down the tree much more rapidly towards the colossal patterns

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Observation: Colossal Patterns and Core Patterns

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A colossal pattern α

D

Dα

α1

Transaction Database D

Dα1

Dα2

α2

α

αk

Dαk

Subpatterns α1 to αk cluster tightly around the colossal pattern α by sharing a similar support. We call such subpatterns core patterns of α

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Robustness of Colossal Patterns

  • Core Patterns

Intuitively, for a frequent pattern α, a subpattern β is a τ-core pattern of α if β shares a similar support set with α, i.e.,

where τ is called the core ratio

  • Robustness of Colossal Patterns

A colossal pattern is robust in the sense that it tends to have much more core patterns than small patterns

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Example: Core Patterns

  • A colossal pattern has far more core patterns than a small-sized pattern
  • A colossal pattern has far more core descendants of a smaller size c
  • A random draw from a complete set of pattern of size c would more likely to pick a core descendant of a colossal pattern
  • A colossal pattern can be generated by merging a set of core patterns

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Transaction (# of Ts)

Core Patterns (τ = 0.5)

(abe) (100)

(abe), (ab), (be), (ae), (e)

(bcf) (100)

(bcf), (bc), (bf)

(acf) (100)

(acf), (ac), (af)

(abcef) (100)

(ab), (ac), (af), (ae), (bc), (bf), (be) (ce), (fe), (e), (abc), (abf), (abe), (ace), (acf), (afe), (bcf), (bce), (bfe), (cfe), (abcf), (abce), (bcfe), (acfe), (abfe), (abcef)

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Robustness of Colossal Patterns

  • (d,τ)-robustness: A pattern α is (d, τ)-robust if d is the maximum number of items that can be removed from α for the resulting pattern to remain a τ-core pattern of α
  • For a (d,τ)-robust pattern α, it has core patterns
    • A colossal patterns tend to have a large number of core patterns
  • Pattern distance: For patterns α and β, the pattern distance of α and β is defined to be

  • If two patterns α and β are both core patterns of a same pattern, they would be bounded by a “ball” of a radius specified by their core ratio τ

  • Once we identify one core pattern, we will be able to find all the other core patterns by a bounding ball of radius r(τ)

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Colossal Patterns Correspond to Dense Balls

  • Due to their robustness, colossal patterns correspond to dense balls
    • Ω( 2^d) in population
  • A random draw in the pattern space will hit somewhere in the ball with high probability

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Idea of Pattern-Fusion Algorithm

  • Generate a complete set of frequent patterns up to a small size
  • Randomly pick a pattern β, and β has a high probability to be a core-descendant of some colossal pattern α
  • Identify all α’s descendants in this complete set, and merge all of them ― This would generate a much larger core-descendant of α
  • In the same fashion, we select K patterns. This set of larger core-descendants will be the candidate pool for the next iteration

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Pattern-Fusion: The Algorithm

  • Initialization (Initial pool): Use an existing algorithm to mine all frequent patterns up to a small size, e.g., 3
  • Iteration (Iterative Pattern Fusion):
    • At each iteration, k seed patterns are randomly picked from the current pattern pool
    • For each seed pattern thus picked, we find all the patterns within a bounding ball centered at the seed pattern
    • All these patterns found are fused together to generate a set of super-patterns. All the super-patterns thus generated form a new pool for the next iteration
  • Termination: when the current pool contains no more than K patterns at the beginning of an iteration

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Why Is Pattern-Fusion Efficient?

  • A bounded-breadth pattern tree traversal
    • It avoids explosion in mining mid-sized ones
    • Randomness comes to help to stay on the right path
  • Ability to identify “short-cuts” and take “leaps”
    • fuse small patterns together in one step to generate new patterns of significant sizes
    • Efficiency

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Pattern-Fusion Leads to Good Approximation

  • Gearing toward colossal patterns
    • The larger the pattern, the greater the chance it will be generated
  • Catching outliers
    • The more distinct the pattern, the greater the chance it will be generated

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Experimental Setting

  • Synthetic data set
    • Diagn an n x (n-1) table where ith row has integers from 1 to n except i. Each row is taken as an itemset. min_support is n/2.
  • Real data set
    • Replace: A program trace data set collected from the “replace” program, widely used in software engineering research
    • ALL: A popular gene expression data set, a clinical data on ALL-AML leukemia (www.broad.mit.edu/tools/data.html).
      • Each item is a column, representing the activitiy level of gene/protein in the same
      • Frequent pattern would reveal important correlation between gene expression patterns and disease outcomes

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Experiment Results on Diagn

  • LCM run time increases exponentially with pattern size n
  • Pattern-Fusion finishes efficiently
  • The approximation error of Pattern-Fusion (with min-sup 20) in comparison with the complete set) is rather close to uniform sampling (which randomly picks K patterns from the complete answer set)

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Experimental Results on ALL

  • ALL: A popular gene expression data set with 38 transactions, each with 866 columns
    • There are 1736 items in total
    • The table shows a high frequency threshold of 30

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Experimental Results on REPLACE

  • REPLACE
    • A program trace data set, recording 4395 calls and transitions
    • The data set contains 4395 transactions with 57 items in total
    • With support threshold of 0.03, the largest patterns are of size 44
    • They are all discovered by Pattern-Fusion with different settings of K and τ, when started with an initial pool of 20948 patterns of size <=3

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Experimental Results on REPLACE

  • Approximation error when compared with the complete mining result
  • Example. Out of the total 98 patterns of size >=42, when K=100, Pattern-Fusion returns 80 of them
  • A good approximation to the colossal patterns in the sense that any pattern in the complete set is on average at most 0.17 items away from one of these 80 patterns

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Mining Compressed Patterns: δ-clustering

  • Why compressed patterns?
    • too many, but less meaningful
  • Pattern distance measure

  • δ-clustering: For each pattern P, find all patterns which can be expressed by P and their distance to P are within δ (δ-cover)
  • All patterns in the cluster can be represented by P
  • Xin et al., “Mining Compressed Frequent-Pattern Sets”, VLDB’05

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ID

Item-Sets

Support

P1

{38,16,18,12}

205227

P2

{38,16,18,12,17}

205211

P3

{39,38,16,18,12,17}

101758

P4

{39,16,18,12,17}

161563

P5

{39,16,18,12}

161576

  • Closed frequent pattern
    • Report P1, P2, P3, P4, P5
    • Emphasize too much on support
    • no compression
  • Max-pattern, P3: info loss
  • A desirable output: P2, P3, P4

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Redundancy-Award Top-k Patterns

  • Why redundancy-aware top-k patterns?

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  • Desired patterns: high significance & low redundancy
  • Propose the MMS (Maximal Marginal Significance) for measuring the combined significance of a pattern set
  • Xin et al., Extracting Redundancy-Aware Top-K Patterns, KDD’06

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Chapter 7 : Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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  • Do they all make sense?
  • What do they mean?
  • How are they useful?

diaper

beer

female sterile (2) tekele

Annotate patterns with semantic information

morphological info. and simple statistics

Semantic Information

Not all frequent patterns are useful, only meaningful ones …

How to Understand and Interpret Patterns?

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A Dictionary Analogy

Word: “pattern” – from Merriam-Webster

Non-semantic info.

Examples of Usage

Definitions indicating

semantics

Synonyms

Related Words

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Semantic Analysis with Context Models

  • Task1: Model the context of a frequent pattern

Based on the Context Model…

  • Task2: Extract strongest context indicators
  • Task3: Extract representative transactions
  • Task4: Extract semantically similar patterns

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Annotating DBLP Co-authorship & Title Pattern

Substructure Similarity Search

in Graph Databases

X.Yan, P. Yu, J. Han

Database:

Title

Authors

Frequent Patterns

P1: { x_yan, j_han }

Frequent Itemset

P2: “substructure search”

Pattern

{ x_yan, j_han}

Non

Sup = …

CI

{p_yu}, graph pattern, …

Trans.

gSpan: graph-base……

SSPs

{ j_wang }, {j_han, p_yu}, …

Semantic Annotations

Context Units

< { p_yu, j_han}, { d_xin }, … , “graph pattern”, �… “substructure similarity”, … >

Pattern = {xifeng_yan, jiawei_han}

Annotation Results:

Context Indicator (CI)

graph; {philip_yu}; mine close; graph pattern; sequential pattern; …

Representative

Transactions (Trans)

> gSpan: graph-base substructure pattern mining;> mining close relational graph connect constraint; …

Semantically Similar Patterns (SSP)

{jiawei_han, philip_yu}; {jian_pei, jiawei_han}; {jiong_yang, philip_yu, wei_wang};

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Advanced Frequent Pattern Mining

  • Pattern Mining: A Road Map
  • Pattern Mining in Multi-Level, Multi-Dimensional Space
  • Constraint-Based Frequent Pattern Mining
  • Mining High-Dimensional Data and Colossal Patterns
  • Mining Compressed or Approximate Patterns
  • Pattern Exploration and Application
  • Summary

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Summary

  • Roadmap: Many aspects & extensions on pattern mining
  • Mining patterns in multi-level, multi dimensional space
  • Mining rare and negative patterns
  • Constraint-based pattern mining
  • Specialized methods for mining high-dimensional data and colossal patterns
  • Mining compressed or approximate patterns
  • Pattern exploration and understanding: Semantic annotation of frequent patterns

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Ref: Mining Multi-Level and Quantitative Rules

  • Y. Aumann and Y. Lindell. A Statistical Theory for Quantitative Association Rules, KDD'99
  • T. Fukuda, Y. Morimoto, S. Morishita, and T. Tokuyama. Data mining using two-dimensional optimized association rules: Scheme, algorithms, and visualization. SIGMOD'96.
  • J. Han and Y. Fu. Discovery of multiple-level association rules from large databases. VLDB'95.
  • R.J. Miller and Y. Yang. Association rules over interval data. SIGMOD'97.
  • R. Srikant and R. Agrawal. Mining generalized association rules. VLDB'95.
  • R. Srikant and R. Agrawal. Mining quantitative association rules in large relational tables. SIGMOD'96.
  • K. Wang, Y. He, and J. Han. Mining frequent itemsets using support constraints. VLDB'00
  • K. Yoda, T. Fukuda, Y. Morimoto, S. Morishita, and T. Tokuyama. Computing optimized rectilinear regions for association rules. KDD'97.

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Ref: Mining Other Kinds of Rules

  • F. Korn, A. Labrinidis, Y. Kotidis, and C. Faloutsos. Ratio rules: A new paradigm for fast, quantifiable data mining. VLDB'98
  • Y. Huhtala, J. Kärkkäinen, P. Porkka, H. Toivonen. Efficient Discovery of Functional and Approximate Dependencies Using Partitions. ICDE’98.
  • H. V. Jagadish, J. Madar, and R. Ng. Semantic Compression and Pattern Extraction with Fascicles. VLDB'99
  • B. Lent, A. Swami, and J. Widom. Clustering association rules. ICDE'97.
  • R. Meo, G. Psaila, and S. Ceri. A new SQL-like operator for mining association rules. VLDB'96.
  • A. Savasere, E. Omiecinski, and S. Navathe. Mining for strong negative associations in a large database of customer transactions. ICDE'98.
  • D. Tsur, J. D. Ullman, S. Abitboul, C. Clifton, R. Motwani, and S. Nestorov. Query flocks: A generalization of association-rule mining. SIGMOD'98.

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Ref: Constraint-Based Pattern Mining

  • R. Srikant, Q. Vu, and R. Agrawal. Mining association rules with item constraints. KDD'97
  • R. Ng, L.V.S. Lakshmanan, J. Han & A. Pang. Exploratory mining and pruning optimizations of constrained association rules. SIGMOD’98
  • G. Grahne, L. Lakshmanan, and X. Wang. Efficient mining of constrained correlated sets. ICDE'00
  • J. Pei, J. Han, and L. V. S. Lakshmanan. Mining Frequent Itemsets with Convertible Constraints. ICDE'01
  • J. Pei, J. Han, and W. Wang, Mining Sequential Patterns with Constraints in Large Databases, CIKM'02
  • F. Bonchi, F. Giannotti, A. Mazzanti, and D. Pedreschi. ExAnte: Anticipated Data Reduction in Constrained Pattern Mining, PKDD'03
  • F. Zhu, X. Yan, J. Han, and P. S. Yu, “gPrune: A Constraint Pushing Framework for Graph Pattern Mining”, PAKDD'07

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Ref: Mining Sequential Patterns

  • X. Ji, J. Bailey, and G. Dong. Mining minimal distinguishing subsequence patterns with gap constraints. ICDM'05
  • H. Mannila, H Toivonen, and A. I. Verkamo. Discovery of frequent episodes in event sequences. DAMI:97.
  • J. Pei, J. Han, H. Pinto, Q. Chen, U. Dayal, and M.-C. Hsu. PrefixSpan: Mining Sequential Patterns Efficiently by Prefix-Projected Pattern Growth. ICDE'01.
  • R. Srikant and R. Agrawal. Mining sequential patterns: Generalizations and performance improvements. EDBT’96.
  • X. Yan, J. Han, and R. Afshar. CloSpan: Mining Closed Sequential Patterns in Large Datasets. SDM'03.
  • M. Zaki. SPADE: An Efficient Algorithm for Mining Frequent Sequences. Machine Learning:01.

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Mining Graph and Structured Patterns

  • A. Inokuchi, T. Washio, and H. Motoda. An apriori-based algorithm for mining frequent substructures from graph data. PKDD'00
  • M. Kuramochi and G. Karypis. Frequent Subgraph Discovery. ICDM'01.
  • X. Yan and J. Han. gSpan: Graph-based substructure pattern mining. ICDM'02
  • X. Yan and J. Han. CloseGraph: Mining Closed Frequent Graph Patterns. KDD'03
  • X. Yan, P. S. Yu, and J. Han. Graph indexing based on discriminative frequent structure analysis. ACM TODS, 30:960–993, 2005
  • X. Yan, F. Zhu, P. S. Yu, and J. Han. Feature-based substructure similarity search. ACM Trans. Database Systems, 31:1418–1453, 2006

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Ref: Mining Spatial, Spatiotemporal, Multimedia Data

  • H. Cao, N. Mamoulis, and D. W. Cheung. Mining frequent spatiotemporal sequential patterns. ICDM'05
  • D. Gunopulos and I. Tsoukatos. Efficient Mining of Spatiotemporal Patterns. SSTD'01
  • K. Koperski and J. Han, Discovery of Spatial Association Rules in Geographic Information Databases, SSD’95
  • H. Xiong, S. Shekhar, Y. Huang, V. Kumar, X. Ma, and J. S. Yoo. A framework for discovering co-location patterns in data sets with extended spatial objects. SDM'04
  • J. Yuan, Y. Wu, and M. Yang. Discovery of collocation patterns: From visual words to visual phrases. CVPR'07
  • O. R. Zaiane, J. Han, and H. Zhu, Mining Recurrent Items in Multimedia with Progressive Resolution Refinement. ICDE'00

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Ref: Mining Frequent Patterns in Time-Series Data

  • B. Ozden, S. Ramaswamy, and A. Silberschatz. Cyclic association rules. ICDE'98.
  • J. Han, G. Dong and Y. Yin, Efficient Mining of Partial Periodic Patterns in Time Series Database, ICDE'99.
  • J. Shieh and E. Keogh. iSAX: Indexing and mining terabyte sized time series. KDD'08
  • B.-K. Yi, N. Sidiropoulos, T. Johnson, H. V. Jagadish, C. Faloutsos, and A. Biliris. Online Data Mining for Co-Evolving Time Sequences. ICDE'00.
  • W. Wang, J. Yang, R. Muntz. TAR: Temporal Association Rules on Evolving Numerical Attributes. ICDE’01.
  • J. Yang, W. Wang, P. S. Yu. Mining Asynchronous Periodic Patterns in Time Series Data. TKDE’03
  • L. Ye and E. Keogh. Time series shapelets: A new primitive for data mining. KDD'09

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Ref: FP for Classification and Clustering

  • G. Dong and J. Li. Efficient mining of emerging patterns: Discovering trends and differences. KDD'99.
  • B. Liu, W. Hsu, Y. Ma. Integrating Classification and Association Rule Mining. KDD’98.
  • W. Li, J. Han, and J. Pei. CMAR: Accurate and Efficient Classification Based on Multiple Class-Association Rules. ICDM'01.
  • H. Wang, W. Wang, J. Yang, and P.S. Yu. Clustering by pattern similarity in large data sets. SIGMOD’ 02.
  • J. Yang and W. Wang. CLUSEQ: efficient and effective sequence clustering. ICDE’03.
  • X. Yin and J. Han. CPAR: Classification based on Predictive Association Rules. SDM'03.
  • H. Cheng, X. Yan, J. Han, and C.-W. Hsu, Discriminative Frequent Pattern Analysis for Effective Classification”, ICDE'07

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Ref: Privacy-Preserving FP Mining

  • A. Evfimievski, R. Srikant, R. Agrawal, J. Gehrke. Privacy Preserving Mining of Association Rules. KDD’02.
  • A. Evfimievski, J. Gehrke, and R. Srikant. Limiting Privacy Breaches in Privacy Preserving Data Mining. PODS’03
  • J. Vaidya and C. Clifton. Privacy Preserving Association Rule Mining in Vertically Partitioned Data. KDD’02

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Mining Compressed Patterns

  • D. Xin, H. Cheng, X. Yan, and J. Han. Extracting redundancy-aware top-k patterns. KDD'06
  • D. Xin, J. Han, X. Yan, and H. Cheng. Mining compressed frequent-pattern sets. VLDB'05
  • X. Yan, H. Cheng, J. Han, and D. Xin. Summarizing itemset patterns: A profile-based approach. KDD'05

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Mining Colossal Patterns

  • F. Zhu, X. Yan, J. Han, P. S. Yu, and H. Cheng. Mining colossal frequent patterns by core pattern fusion. ICDE'07
  • F. Zhu, Q. Qu, D. Lo, X. Yan, J. Han. P. S. Yu, Mining Top-K Large Structural Patterns in a Massive Network. VLDB’11�

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Ref: FP Mining from Data Streams

  • Y. Chen, G. Dong, J. Han, B. W. Wah, and J. Wang. Multi-Dimensional Regression Analysis of Time-Series Data Streams. VLDB'02.
  • R. M. Karp, C. H. Papadimitriou, and S. Shenker. A simple algorithm for finding frequent elements in streams and bags. TODS 2003.
  • G. Manku and R. Motwani. Approximate Frequency Counts over Data Streams. VLDB’02.
  • A. Metwally, D. Agrawal, and A. El Abbadi. Efficient computation of frequent and top-k elements in data streams. ICDT'05

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Ref: Freq. Pattern Mining Applications

  • T. Dasu, T. Johnson, S. Muthukrishnan, and V. Shkapenyuk. Mining Database Structure; or How to Build a Data Quality Browser. SIGMOD'02
  • M. Khan, H. Le, H. Ahmadi, T. Abdelzaher, and J. Han. DustMiner: Troubleshooting interactive complexity bugs in sensor networks., SenSys'08
  • Z. Li, S. Lu, S. Myagmar, and Y. Zhou. CP-Miner: A tool for finding copy-paste and related bugs in operating system code. In Proc. 2004 Symp. Operating Systems Design and Implementation (OSDI'04)
  • Z. Li and Y. Zhou. PR-Miner: Automatically extracting implicit programming rules and detecting violations in large software code. FSE'05
  • D. Lo, H. Cheng, J. Han, S. Khoo, and C. Sun. Classification of software behaviors for failure detection: A discriminative pattern mining approach. KDD'09
  • Q. Mei, D. Xin, H. Cheng, J. Han, and C. Zhai. Semantic annotation of frequent patterns. ACM TKDD, 2007.
  • K. Wang, S. Zhou, J. Han. Profit Mining: From Patterns to Actions. EDBT’02.

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