Text Mining Techniques
for Patent Analysis
Yuen-Hsien Tseng,
National Taiwan Normal University,
samtseng@ntnu.edu.tw
Yuen-Hsien Tseng, Yeong-Ming Wang, Yu-I Lin, Chi-Jen Lin and Dai-Wei Juang, "Patent
Surrogate Extraction and Evaluation in the Context of Patent Mapping", accepted for
publication in Journal of Information Science, 2007 (SSCI, SCI)
Yuen-Hsien Tseng, Chi-Jen Lin, and Yu-I Lin, "Text Mining Techniques for Patent Analysis",
to appear in Information Processing and Management, 2007 (SSCI, SCI, EI)
Outline
• Introduction
• A General Methodology
• Technique Details
• Technique Evaluation
• Application Example
• Discussions
• Conclusions
Introduction – Why Patent
Analysis?
• Patent documents contain 90% research results
– valuable to the following communities:
•
•
•
•
Industry
Business
Law
Policy-making
• If carefully analyzed, they can:
–
–
–
–
–
reduce 60% and 40% R&D time and cost, respectively
show technological details and relations
reveal business trends
inspire novel industrial solutions
help make investment policy
Introduction – Gov. Efforts
• PA has received much attention since 2001
– Korea: to develop 120 patent maps in 5 years
– Japan: patent mapping competition in 2004
– Taiwan: more and more PM were created
• Example: “carbon nanotube” (CNT)
• 5 experts dedicated more than 1 month
• Asian countries, such as, China, Japan, Korean,
Singapore, and Taiwan have invested various
resources in patent analysis
• PA requires a lot of human efforts
– Assisting tools are in great need
Typical Patent Analysis Scenario
1. Task identification: define the scope, concepts, and purposes for
the analysis task.
2. Searching: iteratively search, filter, and download related patents.
3. Segmentation: segment, clean, and normalize structured and
unstructured parts.
4. Abstracting: analyze the patent content to summarize their
claims, topics, functions, or technologies.
5. Clustering: group or classify analyzed patents based on some
extracted attributes.
6. Visualization: create technology-effect matrices or topic maps.
7. Interpretation: predict technology or business trends and
relations.
Technology-Effect Matrix
• To make decisions about future technology development
– seeking chances in those sparse cells
• To inspire novel solutions
– by understanding how patents are related so as to learn how novel
solutions were invented in the past and can be invented in the future
• To predict business trends
– by showing the trend distribution of major competitors in this map
Effect (Function)
Technology
Gas reaction
Manufacture
Catalyst
Arc discharging
Application
Display
Material
Carbon nanotube
5346683
6129901
…
5424054
5780101
…
5424054
Performance
Purity
Electricity
6181055
6190634
6221489
6333016
6190634
6331262
Product
FED
6232706
6339281
5916642
5916642
6346775
5889372
5967873
…
Part of the T-E matrix (from STIC) for “Carbon Nanotube”
Topic Map of Carbon Nanotube
25 docs. : 0.228054 (emission:180.1, field:177.2, emitter:157.1, cathode:108.4, field emission: 88.0)
+ 23 docs. : 0.424787 (emitter:187.0, emission:141.9, field:141.4, cathode:129.0, field emission:104.7)
+ 19 docs. : 0.693770 (emitter:139.7, field emission:132.0, cathode: 96.0, electron: 67.1, display: 61.9)
+ ID=2 : 7 docs.,0.09(cathode:0.58, source:0.56, display:0.50, field emission:0.45, vacuum:0.43)
+ ID=1 : 12 docs.,0.07(emitter:0.67, emission:0.60, field:0.57, display:0.40, cathode:0.38)
+ ID=11 : 4 docs.,0.13(chemic vapor deposition:0.86, sic:0.56, grow:0.44, plate:0.42, thicknes:0.42)
+ ID=19 : 2 docs.,0.21(electron-emissive:1.00, carbon film:0.70, compromise:0.70, emissive material ...
13 docs. : 0.240830 (energy: 46.8, circuit: 34.0, junction: 33.3, device: 26.0, element: 24.9)
+ 9 docs. : 0.329811 (antenna: 31.0, energy: 29.5, system: 29.4, electromagnetic: 25.0, granular: 20.6)
+ ID=4 : 5 docs.,0.07(wave:0.77, induc:0.58, pattern:0.45, nanoscale:0.44, molecule:0.35)
+ ID=15 : 4 docs.,0.12(linear:0.86, antenna:0.86, frequency:0.74, optic antenna:0.70, …)
+ ID=10 : 4 docs.,0.06(cool:0.70, sub-ambient:0.70, thermoelectric cool apparatuse:0.70, nucleate:0.70, ...
Text Mining - Definition
• Knowledge discovery is often regarded as a process to
find implicit, previously unknown, and potentially
useful patterns
– Data mining: from structured databases
– Text mining: from a large text repository
• In practice, TM involves a series of user interactions
with the text mining tools to explore the repository to
find such patterns.
• After supplemented with additional information and
interpreted by experienced experts, these patterns can
become important intelligence for decision-making.
Text Mining Process for Patent Analysis
A General Methodology
• Document preprocessing
–
–
–
–
Collection Creation
Document Parsing and Segmentation
Text Summarization
Document Surrogate Selection
• Indexing
–
–
–
–
Keyword/Phrase extraction
morphological analysis
Stop word filtering
Term association and clustering
• Topic Clustering
–
–
–
–
Term selection
Document clustering/categorization
Cluster title generation
Category mapping
• Topic Mapping
– Trend map
– Query map
-- Aggregation map
-- Zooming map
Example: An US Patent Doc.
• See Example or this URL:
– http://patft.uspto.gov/netacgi/nphParser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=
1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1
&f=G&l=50&s1=5,695,734.PN.&OS=PN/5,695,734
&RS=PN/5,695,734
Download and Parsing into DBMS
NSC Patents
• 612 US patents with assignee contains “National
Science Council” downloaded on 2005/06/15
Distribution of NSC Patents
120
G
100
F
E
80
D
60
C
40
B
A
20
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
0
7
Apply_Year
Patents
H
2
1
Document Parsing and Segmentation
• Data conversion
– Parsing unstructured texts and citations into
structured fields in DBMS
• Document segmentation
– Partition the full patent texts into 6 segments
• Abstract, application, task, summary, feature, claim
– Only 9 empty segments in 6*92=552 CNT patent
segments =>1.63%
– Only 79 empty segments in 6*612=3672 NSC patent
segments => 2.15%
NPR Parsing for
Most-Frequently Cited Journals
and Citation Age Distribution
JouTitle
CitedCount
Appl. Phys. Lett.
23
Plant Molecular Biology
22
IEEE Electron Device Letters
20
Nature
17
Bio/Technology
16
25
1991
Journal of Virology
15
20
1992
J. Biological Chemistry
11
IEEE
11
Plant Physiol.
10
IEEE Journal of Solid-State Circuits
10
J. Appl. Phys.
9
Macromolecules
8
Mol. Gen. Genet.
8
J. Electroanal. Chem.
8
Proc. Nat'l Acad. Sci.
8
J. Chem. Soc.
8
Science
8
Applied Optics
8
Electronics Letters
7
Jpn. J. Appl. Phys.
7
1988
Citation Age Distribution
1989
Num. of Patents
1990
1993
15
1994
1995
10
1996
5
1997
0
1998
0
1
2
3
4
5
6
7
8
9
10
11
Citation Age
12
13
1999
2000
2001
2002
Data are for 612 NSC patents
Automatic Summarization
• Segment the doc. into paragraphs and sentences
• Assess sentences, consider their
–
–
–
–
Positions
Clue words
Title words
keywords
advantage
avoid
cost
costly
decrease
difficult
effectiveness
efficiency
goal
important

weight ( S )  

 wkeywords
• Select sentences
 tf
improved
increase
issue
limit
needed
w
_ or _ titlewords
overhead
performance
problem
reduced
resolve
shorten
simplify
suffer
superior
weakness


 avgtf   FS  P
wcluewords

– Sort by the weights and select the top-k sentences.
• Assembly the selected sentences
– Concatenate the sentences in their original order
Example: Auto-summarization
MS Word (blue) Vs Ours (red)
TITLE (Patent No.: 6,862,710)
Internet navigation using soft hyperlinks
BACKGROUND OF THE INVENTION
Many existing systems have been developed to enable a user to navigate through a set of documents , in order to find one or
more of those documents which are particularly relevant to that user's immediate needs . For example , HyperText Mark-Up
Language ( HTML ) permits web page designers to construct a web page that includes one or more " hyperlinks " ( also
sometimes referred to as " hot links " ) , which allow a user to " click-through " from a first web page to other , different web
pages . Each hyperlink is associated with a portion of the web page , which is typically displayed in some predetermined fashion
indicating that it is associated with a hyperlink .
While hyperlinks do provide users with some limited number of links to other web pages , their associations to the other web
pages are fixed , and cannot dynamically reflect the state of the overall web with regard to the terms that they are associated
with . Moreover , because the number of hyperlinks within a given web page is limited , when a user desires to obtain
information regarding a term , phrase or paragraph that is not associated with a hyperlink , the user must employ another
technique . One such existing technique is the search engine .
Search engines enable a user to search the World Wide Web ( " Web " ) for documents related to a search query provided by
the user . Typical search engines operate through a Web Browser interface . Search engines generally require the user to enter a
search query , which is then compared with entries in an " index " describing the occurrence of terms in a set of documents that
have been previously analyzed , for example by a program referred to sometimes as a " web spider " . Entry of such a search
query requires the user to provide terms that have the highest relevance to the user as part of the search query . However , a
user generally must refine his or her search query multiple times using ordinary search engines , responding to the
search results from each successive search . Such repeated searching is time consuming , and the format of the terms within
each submitted query may also require the user to provide logical operators in a non-natural language format to express his or
her search .
For the above reasons , it would be desirable to have a system for navigating through a document set , such as the Web ,
which allows a user to freely search for documents related to terms , phrases or paragraphs within a web page without
relying on hyperlinks within the web page . The system should further provide a more convenient technique for internet
navigation than is currently provided by existing search engine interfaces .
Evaluation of Each Segment
•
•
•
•
•
•
•
•
abs: the ‘Abstract’ section of each patent
app: FIELD OF THE INVENTION
task: BACKGROUND OF THE INVENTION
sum: SUMMARY OF THE INVENTION
fea: DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENT
cla: Claims section of each patent
seg_ext: summaries from each of the sets: abs, app,
task, sum, and fea
full: full texts from each of the sets: abs, app, task,
sum, and fea
Evaluation Goal
• Analyze a human-crafted patent map to see
which segments have more important terms
• Purposes (so as to):
– allow analysts to spot the relevant segments more
quickly for classifying patents in the map
– provide insights to possibly improve automated
clustering and/or categorization in creating the map
Evaluation Method
• In the manual creation of a technology-effect matrix, it
is helpful to be able to quickly spot the keywords that
can be used for classifying the patents in the map.
• Once the keywords or category features are found,
patents can usually be classified without reading all the
texts.
• Thus a segment or summary that retains as many
important category features as possible is preferable.
• Our evaluation design therefore is to reveal which
segments contains most such features compared to the
others.
Patent Maps for Evaluation
Num. of Cat. in
the Tech.
Taxonomy
Abbr.
Patent Map
Num. of Doc.
Num. of Cat. in the
Effect Taxonomy
CNT
Carbon Nanotube
92
21
9
QDF
Quantum-Dot Fluorescein Detection
11
5
6
QDL
Quantum-Dot LED
27
10
5
QDO
Quantum-Dot Optical Sensor
19
10
3
NTD
Nano Titanium Dioxide
417
17
22
MCM
Molecular Motors
79
21
9
All patent maps are from STPI
Empty segments in the six patent maps
Maps abs app task sum
fea
cla Total empty segments Total segments Empty rate
CNT
0
1
2
5
1
0
9
552
1.63%
QDF
0
0
0
0
0
0
0
66
0.00%
QDL
0
0
0
1
1
0
2
162
1.23%
QDO
0
1
1
2
0
0
4
114
3.51%
NTD
0
62
74
85
103
0
324
2502
12.95%
MCM
0
1
2
1
1
0
5
474
1.05%
Feature Selection
• Well studied in machine learning
• Best feature selection algorithms
Term T
– Chi-square, information gain, …
• But to select only a few features,
correlation coefficient is better than
chi-square
Category
C
Yes
No
Yes
TP
FN
No
FP
TN
• co=1 if FN=FP=0 and TP <>0 and TN <>0
 (T , C ) 
2
( TP  TN - FN  FP )
2
(TP + FN)(FP + TN)(TP + FP)(FN + TN)
Co ( T , C ) 
( TP  TN - FN  FP )
(TP + FN)(FP + TN)(TP
+ FP)(FN + TN)
Best and worst terms by Chi-square
and correlation coefficient
Chi-square
Construction
Correlation coefficient
Non-Construction
Construction
Non-Construction
engineering
0.6210
engineering
0.6210
engineering
0.7880
equipment
0.2854
improvement
0.1004
improvement
0.1004
improvement
0.3169
procurement
0.2231
…
…
kitchen
0.0009
kitchen
0.0009
communiqué
-0.2062
improvement
-0.3169
update
0.0006
update
0.0006
equipment
-0.2854
engineering
-0.7880
Data are from a small real-world collection of 116 documents with only two
exclusive categories, construction vs. non-construction in civil engineering tasks
Some feature terms and their distribution in
each set for the category FED in CNT
term
sc
ss
emit
8
4.86
12
0.62
13
0.58
21
0.55
17
0.59
22
0.70
14
0.61
20
0.63
27
0.59
yes
emission
8
5.07
20
0.69
17
0.59
31
0.62
21
0.73
34
0.63
20
0.63
33
0.64
40
0.54
yes
display
8
5.06
9
0.50
12
0.62
22
0.64
14
0.61
24
0.71
10
0.62
23
0.68
34
0.68
cathode
8
3.86
12
0.39
9
0.42
27
0.48
14
0.54
30
0.53
15
0.51
25
0.52
41
0.47
pixel
7
3.14
3
0.33
8
0.46
3
0.33
12
0.62
2
0.27
5
0.43
17
0.72
screen
5
1.74
2
0.27
2
0.27
8
0.37
18
0.43
19
0.41
yes
electron
5
1.71
27
0.31
25
0.40
yes
voltage
4
1.48
52
0.39
rel
sc ( term ) 
abs
app
Task
36
20
1
term  Segment
sum
0.45
fea
cla
0.28
27
45
0.37
ss ( term ) 
0.37
seg_ext
61
0.35
16
0.28
full
 co ( term )
term  Segment
Note: The correlation coefficients in each segment correlate to the set counts of the
ordered features: the larger the set count, the larger the correlation coefficient in
each segment.
Occurrence distribution of 30 top-ranked
terms in each set for some categories in CNT
category
T_No
abs
App
Task
sum
fea
cla
seg_ext
full
Carbon nanotube
30
15/50.0%
12/40.0%
14/46.7%
20/66.7%
13/43.3%
19/63.3%
20/66.7%
13/43.3%
FED
30
16/53.3%
14/46.7%
22/73.3%
19/63.3%
21/70.0%
19/63.3%
21/70.0%
22/73.3%
device
30
21/70.0%
17/56.7%
9/30.0%
16/53.3%
7/23.3%
19/63.3%
17/56.7%
8/26.7%
Derivation
30
14/46.7%
6/20.0%
7/23.3%
11/36.7%
8/26.7%
13/43.3%
13/43.3%
11/36.7%
electricity
30
12/40.0%
10/33.3%
10/33.3%
10/33.3%
8/26.7%
8/26.7%
13/43.3%
12/40.0%
purity
30
12/40.0%
12/40.0%
7/23.3%
20/66.7%
9/30.0%
17/56.7%
18/60.0%
14/46.7%
High surface area
30
19/63.3%
13/43.3%
13/43.3%
17/56.7%
8/26.7%
9/30.0%
16/53.3%
8/26.7%
magnetic
30
18/60.0%
11/36.7%
6/20.0%
14/46.7%
14/46.7%
13/43.3%
15/50.0%
13/43.3%
energy storage
30
16/53.3%
17/56.7%
13/43.3%
17/56.7%
6/20.0%
10/33.3%
21/70.0%
12/40.0%
M_Best_Term_Coverage(Segment, Category)=
MBTC ( s , c ) 
1
M
1
term  s  c
Occurrence distribution of manually ranked
terms in each set for some categories in CNT
category
T_No
abs
app
task
sum
Carbon nanotube
fea
cla
4
3/75.0%
2/50.0%
2/50.0%
3/75.0%
2/50.0%
2/50.0%
3/75.0%
2/50.0%
FED
7
6/85.7%
6/85.7%
6/85.7%
4/57.1%
6/85.7%
4/57.1%
6/85.7%
5/71.4%
device
2
2/100.0%
1/50.0%
0/0.0%
1/50.0%
1/50.0%
2/100.0%
1/50.0%
0/0.0%
electricity
2
2/100.0%
2/100.0%
2/100.0%
2/100.0%
1/50.0%
2/100.0%
0/0.0%
0/0.0%
purity
2
2/100.0%
2/100.0%
0/0.0%
1/50.0%
1/50.0%
1/50.0%
0/0.0%
1/50.0%
High surface area
8
6/75.0%
2/25.0%
3/37.5%
5/62.5%
1/12.5%
2/25.0%
4/50.0%
1/12.5%
magnetic
5
3/60.0%
1/20.0%
2/40.0%
1/20.0%
3/60.0%
0/0.0%
4/80.0%
3/60.0%
energy storage
2
2/100.0%
2/100.0%
1/50.0%
2/100.0%
1/50.0%
1/50.0%
2/100.0%
0/0.0%
R_Best_Term_Covertage(Segment, Category)= RBTC ( s , c ) 
seg_ext
1
R
1
full
term  s  c  rel
Occurrence distribution of terms in each
segment averaged over all categories in CNT
Set
Taxonomy
nc
abs
app
task
sum
fea
Cla
seg_ext
full
nt
Effect
9
M=30
52.96%
41.48%
37.41%
53.33%
34.81%
47.04%
57.04%
41.85%
Effect*
8
4
86.96%
66.34%
45.40%
64.33%
51.03%
54.02%
55.09%
30.49%
Tech
21
M=30
49.37%
25.56%
26.51%
56.51%
34.44%
46.51%
56.03%
40.95%
Tech*
17
4.5
59.28%
29.77%
23.66%
49.43%
34.46%
60.87%
44.64%
32.17%
M_Best_Term_Coverage(Segment)= MBTC ( s ) 
R_Best_Term_Coverage(Segment)= RBTC ( s ) 
1
Cat
1
Cat

cCat

cCat
1
M
1
R
1
term  s  c
1
term  s  c  rel
Maximum correlation coefficients in each
set averaged over all categories in CNT
Set
Taxonomy
nc
abs
app
task
sum
fea
cla
seg_ext
full
nt
Effect
9
M=30 0.58
0.49
0.54
0.55
0.55
0.57
0.56
0.55
Effect*
8
4.0 0.52
0.43
0.39
0.52
0.48
0.47
0.44
0.33
Tech
21
M=30 0.64
0.58
0.65
0.66
0.66
0.67
0.68
0.68
Tech*
17
4.5 0.47
0.29
0.34
0.44
0.35
0.51
0.43
0.42
*: denoted those calculated from human judged relevant terms
Term-covering rates for M best terms
for the effect taxonomy in CNT
90.00%
80.00%
70.00%
60.00%
10
50.00%
40.00%
30
50
30.00%
20.00%
10.00%
0.00%
abs
app
task
sum
fea
cla
seg_ext
full
Term-covering rates for M best terms
for the technology taxonomy in CNT
90.00%
80.00%
70.00%
60.00%
10
50.00%
40.00%
30
50
30.00%
20.00%
10.00%
0.00%
abs
app
task
sum
fea
cla
seg_ext
full
Term-covering rates for M best terms
80%
80%
70%
70%
60%
60%
50%
10
50%
10
40%
30
40%
30
30%
50
30%
50
20%
20%
10%
10%
0%
0%
abs
app
task
sum
fea
cla
seg_ext
abs
full
app
task
sum
fea
cla
seg_ext
full
QDF: Quantum Dot Fluorescein Detection
90%
90%
80%
80%
70%
70%
60%
10
50%
40%
30
50
30%
60%
10
50%
40%
30
50
30%
20%
20%
10%
10%
0%
0%
abs
app
task
sum
fea
cla
seg_ext
full
abs
app
QDL: Quantum Dot LED
task
sum
fea
cla
seg_ext
full
Term-covering rates for M best terms
90%
80%
70%
60%
10
50%
40%
30
50
30%
20%
10%
0%
abs
app
task
sum
fea
cla
seg_ext
full
80%
70%
10
50%
40%
30
50
30%
20%
10%
0%
abs
app
task
sum
fea
cla
seg_ext
50
90%
80%
80%
70%
70%
60%
60%
10
app
task
sum
fea
cla
seg_ext
30
50
30
50%
40%
50
30%
20%
20%
10%
10%
app
task
sum
fea
cla
seg_ext
abs
app
task
sum
fea
cla
seg_ext
full
10
30
50
abs
app
task
sum
fea
cla
seg_ext
NTD: Nano
Titanium
Dioxide
full
0%
0%
QDO:
QuantumDot Optical
Sensor
full
10
abs
90%
30%
30
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
full
50%
40%
10
abs
90%
60%
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
full
MCM:
Molecular
Motors
Findings
• Most ICFs ranked by correlation coefficient occur in
the “segment extracts”, the Abstract section, and the
SUMMARY OF THE INVENTION section.
• Most ICFs selected by humans occur in the Abstract
section or the Claims section.
• The “segment extracts” lead to more top-ranked ICFs
than the “full texts”, regardless whether the category
features are selected manually or automatically.
• The ICFs selected automatically have higher capability
in discriminating a document’s categories than those
selected manually according to the correlation
coefficient.
Implications
• Text summarization techniques help in patent
analysis and organization, either automatically
or manually.
• If one would determine a patent’s category
based on only a few terms in a quick pace, one
should first read the Abstract section and the
SUMMARY OF THE INVENTION section
• Or alternatively, one should first read the
“segment extracts” prepared by a computer
Text Mining Process for Patent Analysis
• Document preprocessing
–
–
–
–
Collection Creation
Document Parsing and Segmentation
Text Summarization
Document Surrogate Selection
• Indexing
–
–
–
–
Keyword/Phrase extraction
morphological analysis
Stop word filtering
Term association and clustering
• Topic Clustering
–
–
–
–
Term selection
Document clustering/categorization
Cluster title generation
Category mapping
• Topic Mapping
– Trend map
– Query map
-- Aggregation map
-- Zooming map
Ideal Indexing for Topic Identification
Semantic
Resource
processing
(human-prepared)
Byte isolation
Character
identification
Language knowledge
Word
Word segmentation,
Word disambiguity
Lexicon
Phrase
Phrase extraction
POS tagger
Tagged corpus
Morphological
Morphological
analyzer
Linguistic knowledge
Grammar analyzer
Thesaurus, WordNet
Unit
Syntatic processing
Alphabet
Term
Concept
processing: stemmer
Clustering,
feature extraction
Category classification
Understanding
Training data,
Existing DB
No processing may result in low recall; More processing may have false drops.
Example: Extracted Keywords
and Their Associated Terms
1.
2.
Yuen-Hsien Tseng, Chi-Jen Lin, and Yu-I Lin, "Text Mining Techniques for Patent Analysis", to appear in Information
Processing and Management, 2007 (SSCI and SCI)
Yuen-Hsien Tseng, "Automatic Cataloguing and Searching for Retrospective Data by Use of OCR Text", Journal of the
American Society for Information Science and Technology, Vol. 52, No. 5, April 2001, pp. 378-390. (SSCI and SCI)
Clustering Methods
• Clustering is a powerful technique to detect topics and
their relations in a collection.
• Clustering techniques:
–
–
–
–
HAC : Hierarchical Agglomerative Clustering
K-means
MDS: Multi-Dimensional Scaling
SOM: Self-organization Map
• Many open source packages are available
– Need to define the similarity to use them
• Similarities
– Co-words: common words used between items
– Co-citations: common citations between items
Document Clustering
• Effectiveness of clustering relies on
– how terms are selected
• Affect effectiveness most
• Automatic, manual, or hybrid
• Users have more confidence on the clustering results if terms are
selected by themselves, but this is costly
• Manual verification of selected terms is recommended whenever it is
possible
• Recent trend:
– Text clustering with extended user feedback, SIGIR 2006
– Near-duplicate detection by instance-level constrained clustering, SIGIR06
– how they are weighted
• Boolean or TFxIDF
– how similarities are measured
• Cosine, Dice, Jaccard, etc, ..
• Direct HAC document clustering may be prohibited due
to its complexity
Term Clustering
• Single terms are often ambiguous, a group of nearsynonym terms can be more specific in topic
• Goal: reduce number of terms for ease of topic detection,
concept identification, generation of classification
hierarchy, or trend analysis
• Term clustering followed by document categorization
– Allow large collections to be clustered
• Methods:
– Keywords: maximally repeated words or phrases, extracted by
patented algorithm (Tseng, 2002)
– Related terms: keywords which often co-occur with other
keywords, extracted by association mining (Tseng, 2002)
– Simset: a set of keywords having common related terms,
extracted by term clustering
Multi-Stage Clustering
• Single-stage clustering is easy to get skewed distribution
• Ideally, in multi-stage clustering, terms or documents
can be clustered into concepts, which in turn can be
clustered into topics or domains.
• In practice, we need to browse the whole topic tree to
found desired concepts or topics.
Topics
Concepts
Terms or docs.
Cluster Descriptors Generation
• One important step to help analysts interpret the
clustering results is to generate a summary title
or cluster descriptors for each cluster.
• CC (correlation Coefficient) is used
• But CC0.5 or CCxTFC yield better results
• See
– Yuen-Hsien Tseng, Chi-Jen Lin, Hsiu-Han Chen and
Yu-I Lin, "Toward Generic Title Generation for
Clustered Documents," Proceedings of Asia
Information Retrieval Symposium, Oct. 16-18,
Singapore, pp. 145-157, 2006. (Lecture Notes in
Computer Science, Vol. 4182, SCI)
Mapping Cluster Descriptors to Categories
• More generic title words can not be generated
automatically
– ‘Furniture’ is a generic term for beds, chairs, tables,
etc. But if there is no ‘furniture’ in the documents,
there is no way to yield furniture as a title word,
unless additional knowledge resources were used,
such as thesauri
• See also Tseng et al, AIRS 2006
Search WordNet for Cluster Class
• Using external resource to get cluster categories
– For each of 352 (0.005) or 328 (0.001) simsets generated
from 2714 terms
– Submit the sinset heads to WordNet to get their hypernyms
(upper-level hypernyms as categories)
– Accumulate occurrence of each of these categories
– Rank these categories by occurrence
– Select the top-ranked categories as candidates for topic
analysis
– These top-ranked categories still need manual filtering
– Current results are not satisfying
• Need to try to search scientific literature databases which support
topic-based search capability and which have needed categories
Mapping Cluster Titles to Categories
• Search Stanford’s InfoMap
–
http://infomap.stanford.edu/cgi-bin/semlab/infomap/classes/print_class.pl?args=$term1+$term2
• Search WordNet directly
– Results similar to InfoMap
– Higher recall, lower Precision than InfoMap
– Yield meaningful results only when terms are in high quality
• Search google directory: http://directory.google.com/
– Often yield: your search did not match any documents.
– Or wrong category:
• Ex1: submit: “'CMOS dynamic logics‘”
– get: ‘Computers > Programming > Languages > Directories’
• Ex2: submit: “laser, wavelength, beam, optic, light”, get:
– ‘Business > Electronics and Electrical > Optoelectronics and Fiber‘,
– ‘Health > Occupational Health and Safety > Lasers’
• Searching WordNet yield better results but still unacceptable
D:\demo\File>perl -s wntool.pl
=>0.1816 : device%1
=>0.1433 : actinic_radiation%1 actinic_ray%1
=>0.1211 : signal%1 signaling%1 sign%3
=>0.0980 : orientation%2
=>0.0924 : vitality%1 verve%1
NSC Patents
• 612 US patents whose assignees are NSC
• NSC sponsors most academic researches
– Own the patents resulted from the researches
• Documents in the collection are
– knowledge-diversified (cover many fields)
– long (2000 words in average)
– full of advanced technical details
• Hard for any single analyst to analyze them
• Motivate the need to generate generic titles
Text Mining from NSC Patents
• Download NSC patents from USPTO with
assignee=National Science Council
• Automatic key-phrase extraction
– Terms occurs more than once can be extracted
• Automatic segmentation and summarization
– 20072 keywords from full texts vs 19343 keywords from 5
segment summarization
– The 5 segment abstracts contain more category-specific terms
then full texts (Tseng, 2005)
• Automatic index compilation
– Occurring frequency of each term in each document was
recorded
– Record more than 500,000 terms (words, phrases, digits)
among 612 documents in 72 seconds
Text Mining from NSC Patents:
Clustering Methods
• Term similarity is based on common co-occurrence terms
– Phrases and co-occurrence terms are extracted based on Tseng’s
algorithm [JASIST 2002]
• Document similarity is based on common terms
• Complete-link method is used to group similar items
Cluster Info. ID=180, sim=0.19，descriptors: standard:0.77, mpeg:0.73, audio:0.54
Term
DF
Co-occurrence Terms
AUDIO
9
standard, high-fidelity, MPEG, technique, compression, signal,
Multi-Channel.
MPEG
4
standard, algorithm, AUDIO, layer, audio decoding, architecture.
audio decoding
3
MPEG, architecture.
standard
31
AUDIO,MPEG.
compression
29
apparatus, AUDIO, high-fidelity, Images, technique, TDAC,
high-fidelity audio, signal, arithmetic coding.
Term Clustering of NSC Patents
•
Results:
– From 19343 keywords, remove those whose df>200 (36) and df=1 (12330), and those
that have no related terms (4263), resulting in 2714 terms
• Number of terms whose df>5 is 2800
– 352 (0.005) or 328 (0.001) simsets were generated from 2714 terms
•
Good cluster:
–
–
–
–
–
–
•
180 : 5筆,0.19(standard:0.77, mpeg:0.73, audio:0.54)
AUDIO : 9 : standard, high-fidelity, MPEG, technique, compression, signal, Multi-Channel.
MPEG : 4 : standard, algorithm, AUDIO, layer, audio decoding, architecture.
audio decoding : 3 : MPEG, architecture.
standard : 31 : AUDIO,MPEG.
compression : 29 : apparatus, AUDIO, high-fidelity, Images, technique, TDAC, high-fidelity audio,
signal, arithmetic coding.
Wrong cluster:
– 89 : 6筆,0.17(satellite:0.71, communicate:0.54, system:0.13)
– satellite : 8 : nucleotides, express, RNAs, vector, communication system, phase, plant,
communism, foreign gene.
– RNAs : 5 : cDNA, Amy8, nucleotides, alpha-amylase gene, Satellite RNA, sBaMV,
analysis, quinoa, genomic, PAT1, satellite, Lane, BaMV, transcription.
– foreign gene : 4 : express, vector, Satellite RNA, plant, satellite, ORF.
– electrical power : 4 : satellite communication system.
– satellite communication system : 2 : electrical power, microwave.
– communication system : 23 : satellite.
Topic Map for NSC Patents
• Third-stage document clustering result
5. Material
2. Electronics and
Semi-conductors
1.Chemistry
4. Communication
and computers
3. Generality
6. Biomedicine
Topic Tree for NSC Patents
1: 122 docs. : 0.201343 (acid:174.2, polymer:166.8, catalyst:155.5, ether:142.0, formula:135.9)
* 108 docs. : 0.420259 (polymer:226.9, acid:135.7, alkyl:125.2, ether:115.2, formula:110.7)
o 69 docs. : 0.511594 (resin:221.0, polymer:177.0, epoxy:175.3, epoxy resin:162.9, acid: 96.7)
+ ID=131 : 26 docs. : 0.221130(polymer: 86.1, polyimide: 81.1, aromatic: 45.9, bis: 45.1, ether: 44.8)
+ ID=240 : 43 docs. : 0.189561(resin:329.8, acid: 69.9, group: 57.5, polymer: 55.8, monomer: 44.0)
o ID=495 : 39 docs. : 0.138487(compound: 38.1, alkyl: 37.5, agent: 36.9, derivative: 33.6, formula: 24.6)
* ID=650 : 14 docs. : 0.123005(catalyst: 88.3, sulfide: 53.6, iron: 21.2, magnesium: 13.7, selective: 13.1)
2: 140 docs. : 0.406841 (silicon:521.4, layer:452.1, transistor:301.2, gate:250.1, substrate:248.5)
* 123 docs. : 0.597062 (silicon:402.8, layer:343.4, transistor:224.6, gate:194.8, schottky:186.0)
o ID=412 : 77 docs. : 0.150265(layer:327.6, silicon:271.5, substrate:178.8, oxide:164.5, gate:153.1)
o ID=90 : 46 docs. : 0.2556(layer:147.1, schottky:125.7, barrier: 89.6, heterojunction: 89.0, transistor: …
* ID=883 : 17 docs. : 0.103526(film: 73.1, ferroelectric: 69.3, thin film: 48.5, sensor: 27.0, capacitor: 26.1)
3: 66 docs. : 0.220373 (plastic:107.1, mechanism: 83.5, plate: 79.4, rotate: 74.9, force: 73.0)
* 54 docs. : 0.308607 (plastic:142.0, rotate:104.7, rod: 91.0, screw: 85.0, roller: 80.8)
o ID=631 : 19 docs. : 0.125293(electromagnetic: 32.0, inclin: 20.0, fuel: 17.0, molten: 14.8, side: 14.8)
o ID=603 : 35 docs. : 0.127451(rotate:100.0, gear: 95.1, bear: 80.0, member: 77.4, shaft: 75.4)
* ID=727 : 12 docs. : 0.115536(plasma: 26.6, wave: 22.3, measur: 13.3, pid: 13.0, frequency: 11.8)
4: 126 docs. : 0.457206 (output:438.7, signal:415.5, circuit:357.9, input:336.0, frequency:277.0)
* 113 docs. : 0.488623 (signal:314.0, output:286.8, circuit:259.7, input:225.5, frequency:187.9)
o ID=853 : 92 docs. : 0.105213(signal:386.8, output:290.8, circuit:249.8, input:224.7, light:209.7)
o ID=219 : 21 docs. : 0.193448(finite: 41.3, data: 40.7, architecture: 38.8, computation: 37.9, algorithm: …
* ID=388 : 13 docs. : 0.153112(register: 38.9, output: 37.1, logic: 32.2, addres: 28.4, input: 26.2)
5: 64 docs. : 0.313064 (powder:152.3, nickel: 78.7, electrolyte: 74.7, steel: 68.6, composite: 64.7)
* ID=355 : 12 docs. : 0.1586(polymeric electrolyte: 41.5, electroconductive: 36.5, battery: 36.1, electrode: ...
* ID=492 : 52 docs. : 0.138822(powder:233.3, ceramic:137.8, sinter: 98.8, aluminum: 88.7, alloy: 63.2)
6: 40 docs. : 0.250131 (gene:134.9, protein: 77.0, cell: 70.3, acid: 65.1, expression: 60.9)
* ID=12 : 11 docs. : 0.391875(vessel: 30.0, blood: 25.8, platelet: 25.4, dicentrine: 17.6, inhibit: 16.1)
* ID=712 : 29 docs. : 0.116279(gene:148.3, dna: 66.5, cell: 65.5, sequence: 65.1, acid: 62.5)
Total: 558 docs.
Major IPC Categories for NSC patents
A: 87 docs. : Human Necessities
+ A61: 71 docs. : Medical Or Veterinary Science; Hygiene
+ A*: 16 docs. : A01(7), A21(2), A23(2), A42(2), A03(1), A62(1), A63(1)
B: 120 docs. : Performing Operations; Transporting
+ B01: 25 docs. : Physical Or Chemical Processes Or Apparatus In General
+ B05: 28 docs. : Spraying Or Atomising In General; Applying Liquids Or Other Fluent Materials To Surfaces
+ B22: 17 docs. : Casting; Powder Metallurgy
+ B*: 50 docs. : B32(12), B29(11), B62(6), B23(4), B24(4), B60(4), B02(2), B21(2), B06(1), B25(1), …
C: 314 docs. : Chemistry; Metallurgy
+ C07: 62 docs. : Organic Chemistry
+ C08: 78 docs. : Organic Macromolecular Compounds; Their Preparation Or Chemical Working-Up; …
+ C12: 76 docs. : Biochemistry; Beer; Wine; Vinegar; Microbiology; Mutation Or Genetic Engineering; …
+ C* : 98 docs. : C23(22), C25(20), C01(19), C04(10), C09(10), C22(8), C03(5), C30(3), C21(1)
D: 6 docs. : Textiles; Paper
E: 8 docs. : Fixed Constructions
F: 30 docs. : Mechanical Engineering; Lighting; Heating;
G: 134 docs. : Physics
+ G01: 49 docs. : Measuring; Testing
+ G02: 28 docs. : Optics
+ G06: 29 docs. : Computing; Calculating; Counting
+ G*: 28 docs. : G10(7), G11(7), G05(6), G03(5), G08(2), G09(1)
H: 305 docs. : Electricity
+ H01: 216 docs. : Basic Electric Elements
o H01L021: 92 docs. : Processes or apparatus adapted for the manufacture or treatment of semiconductor
o H01L029: 35 docs. : Semiconductor devices adapted for rectifying, amplifying, oscillating, or switching;
o H01L*: 89 docs. : others.
o H01*: 53 docs. : H03K(23), H03M(11), H04B(10), H04L(7), H04N(7), H01B(5), H03H(4), H04J(4), …
+ H03: 51 docs. : Basic Electronic Circuitry
+ H04: 30 docs. : Electric Communication Technique
+ H*: 8 docs. : H05(5), H02(3)
Division Distributions of NSC Patents
Abbrev.
Ele
Che
Mat
Opt
Med
Mec
Bio
Com
Inf
Civ
Others
Total
Division
Electrical Engineering
Chemical Engineering
Material Engineering
Optio-Electronics
Medical Engineering
Mechanical Engineering
Biotechnology Engineering
Communication Engineering
Information Engineering
Civil Engineering
Percentage
28.63%
14.70%
14.12%
13.15%
10.44%
6.58%
5.03%
2.90%
2.90%
1.16%
0.39%
100.00%
Distribution of Major IPC Categories
in Each Cluster
others
F
B05
B* H*
C08
C*
B01
A61
C07
Cluster 1
others
G01
C*
H01L
029
others
H01L
021
H
Cluster 2
B*
B22
H*
A*
E
Cluster 3
others
G*
G01
F
G01
others
H03
G02
H04
H* G06
Cluster 4
others
B01
H*
B22
C07
C*
Cluster 5
A61
C12
Cluster 6
Distribution of Academic Divisions
in Each Cluster
Mat
Bio
Opt
Ele
Civ
Che
Che
Mat
Che
CivInf
Opt
Opt
Mec
Ele
Ele
Mat
Med
Cluster 1
Inf
Med
Che
Mec
Cluster 2
Cluster 3
Ele
Ele
Com
Mat
Che
Bio
Med
Opt
Cluster 4
Cluster 5
Cluster 6
Comparison among the Three Methods
• The three classification systems provide different facets to
understand the topic distribution of the patent set.
• Each may reveal some insights if we can interpret it.
• The IPC system results in divergent and skewed distributions
which make it hard for further analysis (such as trend analysis).
• The division classification is the most familiar one to the NSC
analysts, but it lacks inter-disciplinary information.
• As to the text mining approach, it dynamically glues related IPC
categories together based on the patent contents to disambiguate
their vagueness.
• This makes future analysis possible even when the division
information is absent, as may be the case in later published
patents to which NSC no longer claims their right.
Other Methods: SOM
The 16x16 SOM for the NSC patents obtained by the tool from Peter Kleiweg
Other Methods: Citation Analysis
• Among 612 NSC patents:
• Only 123 patents are co-cited by others
– resulting in 99 co-cited pairs.
• Only 175 patents co-cite others
– resulting in 143 co-citing pairs.
• Such sparseness may lead to biased analysis.
• Citation analysis is not suitable in this case.
Conclusions
• Used text mining techniques:
–
–
–
–
text segmentation
summary extraction
keyword identification
topic detection (taxonomy generation, term clustering)
• Achievement:
– better classification than IPC
– As more interactions are involved in nowadays researches,
inter-disciplinary relations are interesting to monitor.
– Provide this information that NSC Divisions lack
• “Problems to be solved” is likely to be extracted from the
“Background of the Invention”
• However, “Solutions” is hard to extract
Types of Patent Maps
• Trend maps : two kinds for showing the trends:
– Growth mode: accumulate patents over time
– Evolution mode: divide patents over time
– Both are made by fixing the clusters obtained from clustering all patents
and then divide the patents in each cluster in a timely fashion and
recalculate the similarities among these clusters.
• Query maps:
– Showing only those patents satisfying some conditions in each cluster
• Aggregation maps :
– Aggregated results based on some specified attributes are show in each
cluster
• Zooming maps:
– Some clusters can be selected and zoomed in or out to show the details or
the overviews