Biosurveillance 2.0 Collaboration and Web 2.0/3.0 Semantic
Technologies for Better Early Disease Warning and Effective Response
Taha Kass-HoutNicolás di Tada
Invited by Dr. Barbara Massoudi, PhD, MPH
Lecture at Emory University Rollins School of Public Health
Public Health Informatics, INFO 503
Atlanta, GA, USA
Background
DAY
CA
SE
S
Opportunity for control
Background
Late Detection and Response
DAY
CA
SE
S
Opportunity for control
Background
Early Detection and Response
Public Health Measures
• Representativeness
• Completeness
• Predictive Value
• Timeliness
Background
Public Health Measures
1000 Malaria infections (100%)
50 Malaria notifications (5%)
Get as close to the bottom of the pyramid
as possible
Urge frequent reporting: Weekly daily immediately
Specificity / Reliability
Sensitivity / Timeliness • Main attributes
o Representativenesso Completenesso Predictive value positive
Background
Analyze and interpret
Signal as early
as possible
Automated analysis/thresholds
Time
• Main attributeso Timeliness
Public Health MeasuresHealth care hotline
Background
Public Health – Two Perspectives
• Case management – Individual cases of notifiable diseases– Relationship networks (contact
tracing)
• Population surveillance– Larger risk patterns
Background
Case Management
• Questions and problems:– Is a case due to recent transmission?– If so, does the case share any feature with
other recent cases?
• Current methods:– Investigations and interviews– Meeting with other investigators
Background
Population Surveillance
• Questions and problems:– Are more cases happening than expected?– Does an excess suggest ongoing transmission
in a specific region?
• Current methods:– Semi-automated routine temporal and
space-time statistical analysis
Background
Why location matters:Case Management
• If you are studying a case of a certain disease that was just declared
• It is harder to picture the situation by looking at something like this...
Background
Background
Why location matters:Case Management
Why location matters:Case Management
• Than by looking at this..
Background
Why location matters:Case Management
Background
Why location matters:Population Surveillance
• If you are studying the spatial distribution of a set of disease clusters, this next slide seems more difficult…
Background
Why location matters:Population Surveillance
Background
Why location matters:Population Surveillance
• Than this...
Background
Why location matters:Population Surveillance
Background
The Problem Space
• Current systems design, analysis and evaluation has been geared towards specific data sources and detection algorithms – not humans
• We have systems in place for those threats we have been faced with before
The Problem
Traditional DISEASE SURVEILLANCE
• In the past two decades focus was on – automatically detecting anomalous patterns in
data (often a single stream)
• Modern methods– rely on human input and judgment – incorporate temporal, spatial, and multivariate
information
The Problem
9/20, 15213, cough/cold, …9/21, 15207, antifever, …9/22, 15213, CC = cough, ...1,000,000 more records…
Huge mass of data Detection algorithm “What are we supposed to do with
this?”
Too many alerts
Traditional DISEASE SURVEILLANCE
The Problem
Our Approach
• Human-based
• Collaborative and cross-disciplinary
• Web 2.0/3.0 platform
Our Approach
Information Sources
• Event-based - ad-hoc unstructured reports issued by formal or informal sources
• Indicator-based - (number of cases, rates, proportion of strains…)
Timeliness, Representativeness, Completeness, Predictive Value, Quality, …
Our Approach
9/20, 15213, cough/cold, …9/21, 15207, antifever, …9/22, 15213, CC = cough, ...1,000,000 more records…
Huge mass of data
Feedback loop
MODERN DISEASE SURVEILLANCE
Our Approach
Fewer and more actionable alerts
Effective and coordinated response
Evolve: Main Components
Feature extraction, reference and baseline information
Tags
Multiple Data Streams
User-Generated and Machine Learning Metadata
Comments
Spatio-temporal
Flags/Alerts/Bookmarks
Evo
lve Bo
t
Event Classification,
Characterization and Detection
Previous Event Training Data
Previous Event Control Data
Metadataextraction
Machine learning
Social network
Professional feedback
Anomaly detection
Collaborative Spaces
Hypotheses generation\testing
Our Solution
Evolve: Main Components
Our Solution
Item
Hypothesis
Field Actions and Verifications
Feedback / Confirmation
Our Solution
Evolve: Process
Item ItemItem
Item
Item Item
ItemItem
Advantages of Machine Learning
P(malaria) = 22% P(influenza) = 13% P(other ILI) = 33%
Our Solution
Machine Learning Techniques
1. Classifiers
2. Clustering
3. Bayesian Statistics
4. Neural Networks
5. Genetic Algorithms
Our Solution
How to represent a document:
cold
fever
Our Solution
(1) Classifiers:Problem Definition
• Map items to vectors (Feature extraction)
• Normalize those vectors
• Train the classifier
• Measure the results with new information
• Feedback the classifier
• Separate classes in feature space
Our Solution
Classifiers:Support Vector Machines (SVM)
Our Solution
SVM – Margin Maximization
• Support vectors define the separator
Our Solution
SVM – Non-linear?
Φ: x → φ(x)
Map to higher-dimension space
Our Solution
SVM – Filtering or classifying
ClassifierClassifier
Document 1
Document 1
Document 2
Document 2
Document 3
Document 3
PositivesPositives
NegativesNegatives
Training DocumentTraining
DocumentTraining
DocumentTraining
Document
Our Solution
(2) Clustering:Problem Definition
• Map items to vectors (Feature extraction)
• Normalization
• Agglomerative or Partitional
Our Solution
Clustering: AGGLOMERATIVE
Our Solution
Clustering: PARTITIONAL
Our Solution
(3) Bayesian Statistics
P(A |B) P(B | A).P(A)
P(B)
Probability of disease A (flu)
once symptom B (fever) is observed
Probability of disease A (flu)
once symptom B (fever) is observed
Probability of fever once flu is confirmed
Probability of fever once flu is confirmed
Probability of flu (prior or marginal)
Probability of flu (prior or marginal)
Probability of fever (prior or
marginal)
Probability of fever (prior or
marginal)
Our Solution
(4) Neural Networks
• Given a set of stimuli, train a system to produce a given output…
Our Solution
Hidden LayerHidden Layer
Output LayerOutput Layer
Input LayerInput Layer
Neural Network: Structure
[…]
[…]
{I0,I1,……In}
{O0,O1,……On}
Weight
Weight
).(0 in
I
i in wIH
Our Solution
Neural Network:Application
Event?
Our Solution
(5) Genetic Algorithm:Basic
• Define the model that you want to optimize
• Create the fitness function
• Evolve the gene pool testing against the fitness function.
• Select the best individual
Our Solution
Genetic Algorithm:Model
• Model the transmission process using a set of parameters (e.g., an infectious disease):– Onset time between an infection and illness– Latency period– Incubation period– Symptomatic period– Infectious period
(Onset, Latency, Incubation, Symptomatic , Infectious)
( 2 days, 3 days, 1 day, 4 days, 3 days)
Our Solution
Genetic Algorithm:Model Fitness
Fitness = 1/AreaFitness = 1/Area
Our Solution
Genetic Algorithm:Process
1. Create an initial population of candidates
2. Use operators to generate new candidates (mating and mutation)
3. Discard worst individuals or select best individuals in generation
4. Repeat from 2 until you find a candidate that satisfies the solution searched
Our Solution
(4,5,6,3,5) (4,3,6,2,5)
Genetic Algorithm:Process
(5,3,4,6,2) (2,4,6,3,5) (4,3,6,5,2)
(2,3,4,6,5) (3,4,5,2,6)
(3,5,4,6,2) (4,5,3,6,2) (5,4,2,3,6)
(4,6,3,2,5) (3,4,2,6,5) (3,6,5,1,4)
(5,3,2,6,5)
(3,4,4,6,2)
(5,3,2,6,5)
(3,4,4,6,2)
Our Solution
Result of incorporating all 5 techniques:Improved Surveillance
Our Solution
Our Solution
InSTEDD Evolve
Related items (e.g., News articles) are grouped into a thread. Threads are later associated with events (hypothesized or confirmed).
Related items (e.g., News articles) are grouped into a thread. Threads are later associated with events (hypothesized or confirmed).
InSTEDD Evolve: (http://instedd.org/evolve)
Tag cloud and semantic heatmap
Tag cloud and semantic heatmap
Our Solution
InSTEDD Evolve
InSTEDD Evolve: (http://instedd.org/evolve)
Filter feature which automatically filters for related items, updates the map and associated tagsFilter feature which automatically filters for related items, updates the map and associated tags
Our Solution
InSTEDD Evolve
InSTEDD Evolve: (http://instedd.org/evolve)
Auto-generated (machine-learning) tags. These tags are semantically ranked (a
statistical probability match). Users can further train the classifier by accepting or rejecting a suggestion. Users can similarly
train the geo-locator by simply accepting or rejecting and updating a location.
Auto-generated (machine-learning) tags. These tags are semantically ranked (a
statistical probability match). Users can further train the classifier by accepting or rejecting a suggestion. Users can similarly
train the geo-locator by simply accepting or rejecting and updating a location.
Our Solution
InSTEDD Evolve
InSTEDD Evolve: (http://instedd.org/evolve)
Tracking the recent Avian Influenza Outbreak in Egypt (reports started to appear late January 2009). Notice the pattern of reported incidents along the Nile river.
Tracking the recent Avian Influenza Outbreak in Egypt (reports started to appear late January 2009). Notice the pattern of reported incidents along the Nile river.
Acknowledgements
Through funding from:
Thank You!
Taha Kass-Hout Nicolás di Tada
BACKGROUND MATERIAL
Index• Disease surveillance References
– Computing– Automating Laboratory Reporting– Using EMR data for disease surveillance– Related Projects– Misc Readings
• Open Source Software (OSS) References– Open Source License References– Open Source References– Open Source and Public Health References
• Architectural Matters– Service Oriented Architecture (or SOA)– Synchronization Architecture– Cloud Architecture
DISEASE SURVEILLANCEReferences and Related-Efforts
REFERENCES• Izadi, M. and Buckeridge, D., Decision Theoretic Analysis of Improving Epidemic
Detection, AMIA 2007, Symposium Proceedings 2007• EpiNorth-Based material (http://www.epinorth.org):
– Mereckiene, J., Outbreak Investigation Operational Aspects. Jurmala, Latvia, 2006
– Bagdonaite, J., and Mereckiene, J., Outbreak Investigation Methodological aspects. Jurmala, Latvia, 2006
– Epidemic Intelligence: Signals from surveillance systems, Anne Mazick, Statens Serum Institut, Denmark, EpiTrain III, Jurmala, August 2006
• Daniel Neil, Incorporating Learning into Disease Surveillance Systems
REFERENCES• Computing
– The Future of Statistical Computing in Wilkinson (2008)– Complex Event Processing Over Uncertain Data in Wasserkrug (2008)– Outbreak detection through automated surveillance A review of the
determinants of detection in Buckeridge (2007) – Approaches to the evaluation of outbreak detection methods in
Watkins (2006)– Algorithms for rapid outbreak detection a research synthesis
Buckeridge (2004)– Data mining in bioinformatics using Weka in Frank (2004)– Aho-Corasick Algorithm in Kilpeläinen
• Automating Laboratory Reporting– Automatic Electronic Laboratory-Based Reporting in Panackal (2002)– Benefits and Barriers to Electronic Laboratory Results Reporting for Notifiable
Diseases in Nguyen (2007)
REFERENCES• Using EMR Data for Disease Surveillance
– Using Electronic Medical Records to Enhance Detection and Reporting of Vaccine Adverse Events in Hinrichsen (2007)
– Electronic Medical Record Support for PH in Klompas (2007)– A knowledgebase to support notifiable disease surveillance in Doyle (2005)– Automated Detection of Tuberculosis Using Electronic Medical Record Data in
Calderwood (2007)• Misc Readings
– Breakthrough in modeling emerging disease hotspots in Jones (2008)– Use of data mining techniques to investigate disease risk classification as a
proxy for compromised biosecurity of cattle herds in Wales in Ortiz-Pelaez (2008)
– Euclidean distance: http://en.wikipedia.org/wiki/Euclidean_distance – Tags/Folksonomy:
• Tag Decay: A View Over Aging Folksonomy in Russell (2007)• Cloudalicious: Folksonomy Over Time in Russell (2006)
RELATED PROJECTS• InSTEDD Evolve: (http://instedd.org/evolve)
– Collaborative Analytics and Environment for Linking Early Health-Related Event Detection to an Effective Response (http://taha.instedd.org/2008/09/collaborative-analytics-and-environment.html )
• ALPACA "ALPACA Light Parsing And Classifying Application (ALPACA) is a classifying tool designed for use in community-oriented software as well as in Academia. The application consists of two parts: a parsing tool for transforming raw documents into readable data, and a classifying tool for categorizing documents into user-provided classes. The application provides a user-friendly interface and a Plug-in functionality to provide a simple way to add more parsers/classifiers to the application." http://2008.hfoss.org/ALPACA
• Weka An open source "...collection of machine learning algorithms for data mining tasks. The algorithms can either be applied directly to a dataset or called from your own Java code. Weka contains tools for data pre-processing, classification, regression, clustering, association rules, and visualization. It is also well-suited for developing new machine learning schemes." http://www.cs.waikato.ac.nz/~ml/weka/
RELATED PROJECTS• The R Project for statistical computing: http://www.r-project.org
– Surveillance Project: An Open Source R-package disease surveillance framework for "...the development and the evaluation of outbreak detection algorithms in univariate and multivariate routine collected public health surveillance data." http://surveillance.r-forge.r-project.org
• The R package surveillance in Höhle (multiple articles)
• Google's Research Publications: MapReduce Simplified Data Processing on Large Clusters (http://labs.google.com/papers/mapreduce.html)– Hadoop: a software platform that lets one easily write and run applications
that process vast amounts of data (http://hadoop.apache.org/core)
OPEN SOURCE SOFTWAREReferences and Related-Efforts
REFERENCES• Open Source License References
– http://www.opensource.org/licenses – http://openacs.org/about/licensing/open-source-licensing
• Open Source References– http://www.lifehack.org/articles/technology/open-source-life-how-the-open-
movement-will-change-everything.html – http://en.wikipedia.org/wiki/Open_source – http://www.opensource.org/
• Open Source and Public Health References– http://www.ibiblio.org/pjones/wiki/index.php/
Open_Source_Software_for_Public_Health – http://en.wikipedia.org/wiki/List_of_open_source_healthcare_software – http://www.epha.org/a/320 – Open Source Development for Public Health: A Primer with Examples of Existing
Enterprise Ready Open Source Applications in Turner (2006)– A Quick Survey of Open Source Software for Public Health Organizations in Mirabito
and Kass-Hout (2007)
ARCHITECTURAL MATTERSReferences and Related-Efforts
REFERENCES• Service Oriented Architecture (or SOA)
– Proposal for Fulfilling Strategic Objectives of the U.S. Roadmap for National Action on Decision Support through a Service—oriented Architecture Leveraging HL7 Services in Kawamoto (2007)
– Service-oriented Architecture in Medical Software: Promises and Perils in Nadkarni (2007)
– Wiki sources:• SOA: http://en.wikipedia.org/wiki/Service_Orientated_Architecture • Semantic service oriented architecture:
http://en.wikipedia.org/wiki/Semantic_service_oriented_architecture • Synchronization Architecture
– InSTEDD’s Mesh4x: http://mesh4x.org • Cloud Architecture
– Google App Engine: Google App Engine Goes Up Against Amazon Web Services in Gartner Report (2008)
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