1.
INDUSTRIAL DATA SCIENCE
Tuesday 20 August 2013

2.
WHY DO WE NEED BIG DATA?

3.
SIMPLE MODELS AND A LOT OF DATA
TRUMP MORE ELABORATE MODELS
BASED ON LESS DATA
Peter Norvig
“
”

4.
BIG DATA CHANGES PEOPLE AND TECHNOLOGY
• Data changes the management mindset to expect having supporting data
available for all decisions
• Decision making then creates its own data stream that can be analyzed
• Data is an asset: What is its return? Net value? Depreciation? Future
investment plan?

5.
IN GOD WE TRUST,
ALL OTHERS BRING DATA
W.E. Deming
“
”

6.
DEPLOYING DATA

7.
DATA STORAGE FOR LEARNING
• Efficient storage is critical for modeling feasibility
• What is efficient storage depends on data, algorithms and environment
• Memory: working sets, small data, online learning, fast iterations needed
• Disk: M-estimation, local context sufficient
• Data warehouse: simple models in enterprises, complex input generation
• Distributed: stochastic/ensemble methods, large and complex production models
• Cloud: variable workloads, very massive data

8.
UNSUPERVISED LEARNING IN USE
Modeling
Significance
testing
Decision making
As input into
other modeling
Know-how
Selection of
useful pattern
types

9.
DEPLOYMENT OF A COMMON MODEL
Modeling tool
DatabaseService
Prediction request
and answer
Datasets
periodically
for learning
Predictions
written to DB

10.
DEPLOYMENT OF A LOCALIZED MODEL
Modeling tool
DatabaseService
Prediction request
and answer
Datasets
periodically
for learning
Predictions
Data builder
Input
construction
Query
input

11.
DEPLOYMENT OF ONLINE LEARNING
Modeling tool
Database
Incoming
data stream
Service
Data and/or
labels
Requests
with data
Predictions
Data and/or
labels

12.
EVALUATING RESULTS AND QUALITY
• Properly evaluating the quality of modeling results depends on project
objectives, error costs and data specifics
• Classification error makes no sense for skewed class sizes,
ranks and ROC curves do
• Operational improvements evaluated as lift and incremental $$$ over previous
• Uneven error costs:
• earthquake risk estimation
• medical research, molecule potential VS patient safety
• Upsetting recommendations to an e-commerce customer

13.
WHAT IS REAL-TIME?
• Real-time can mean very different things to different people
• Analyst: “What’s the user count today? By source? Now? From France?”
• Sysadmin: “Network traffic up 5x in 5 seconds! What’s going on?”
• Google: “Make a bid for these placements. You have 50 ms”

14.
PROCESSING LARGE DATA

15.
EXAMPLES OF DATA SIZE
Human-generated
• 5K tweets/s
• 25K events/s from a mobile game (that’s 200 GB / day)
• 40K Google searches/s
Machine-generated
• 5M quotes/s in the US options market
• 120 MB/s of diagnostics from a single gas turbine
• 1 PB/s peaking from CERN LHC

16.
HUMAN AND MACHINE GENERATED DATA
• Human-generated data will get more detailed
• … but won’t grow much faster than the underlying userbase
• It will become small eventually
• Machine-generated data will grow by the Moore’s law
• … and it’s already massive

17.
PROCESSING DATA THE OLD WAY
• User actions modify the current state in a transaction DB
• Single events go to an offline audit log for re-running
• Snapshots of data are exported for modeling
• Production models take exports of snapshots,
write back snapshot versioned results
Events
Snapshot
Snapshot
Snapshot

18.
PROCESSING DATA IN STATUS QUO
• Data from operational databases is constantly copied over to a data
warehouse or an analytic database
• This is idealistically a one-stop-shop for all analytics and data science
• Production models preferably work inside the database,
providing high performance and data integrity
• Model learning can try pushing back some operations to the database, but
complex models will need an external tool
• Expensive modeling may require a separate testing database

19.
PROCESSING DATA IN THE CLOUD
• Cloud allows endless scale
• No fixed limits on CPU and data usage, but everything is I/O-bound
• Enterprise hybrid clouds allow testing environments and “cloud bursting”
• Large datasets may require specialized algorithms or retrofits to MapReduce
• Combining stochastic learning, online learning and ensemble methods has
proven itself for the task

20.
PRACTICAL ISSUES

21.
REAL WORLD DATA IS RIDDLED WITH PROBLEMS
• Corrupted incoming data
• Corrupted IDs
• Transient IDs
• Multiple transient IDs without match
• Crazy timestamps
• Data types mixed up
• New variables emerge
• Old variables disappear
• Changes in variable definitions
• And much, much more …
You
Garbage Great insights

22.
AND WITH MORE PROBLEMS
• Collected data is enriched with many operationally attainable sources
⇒ varying schemas and complicated ID soup
• Analytic data often developed by frontline instead of IT waterfall
⇒ faster process, but volatile data definition
• Data scientists asking for more data ⇒ temporary kludges
• Data is big and growing ⇒ risks of unnoticed discontinuity

23.
NO, I’M NOT FINISHED YET
• The data is not a CSV file sitting in your disk
• It’s coming in every second of the year, often gigabytes per hour
• Availability of this data is a business critical issue
• Availability of modeling results is a business critical issue
• Robustness of modeling results is a business critical issue

24.
DATA DRIFT
• Real-world data is rarely stationary
• Equipment ages, people’s preferences change
• Quality of old data models decay
• Training and testing data may need to be specially designed
• Prefer recent data with weights or online learning

25.
ROBUST RESULTS?
• Inputs to a decision making process must be assessed for significance
“Can I trust these numbers? Is my decision justified?”
• Ad-hoc analyses can freely employ complex and bleeding edge modeling
• In operations stability and robustness overrides everything else
• Sanity checks and fallbacks can be used to avoid failures and errors

26.
POWER LAWS
Number of users
Revenue per user

27.
POWER LAWS
• Power laws are ubiquitous in the real world
• Follows from principle: “Whoever has will be given more”
• Example: new links emerge to web pages in proportion to their popularity
• Product improvements can be tracked through changes in the power law curve
• Examples
• Power laws often have a cut-off in the beginning,
not enough mass to fill the lowest ranks
• User engagement and value
• Social network activity
• Brain activity
• Wealth distribution

28.
CONSEQUENCES OF POWER LAWS
• Power laws imply extremely skewed distributions
⇒ most models assume Gaussian or generally more balanced distribution
• Huge mass at the bottom ladder breaks most traditional analyses
• Different parts of the curve have complex real world interaction
• On the other hand it is relatively easy to segment power laws
⇒ separately designed treatment for different target groups
• Bringing new users as part of the power law lifts the whole curve as new
entries slowly diffuse along the curve

29.
THE IMPORTANCE OF PRESENTATION
• Operations or not, visualization is critical for acceptance
• Challenger shuttle disaster linked to poor visualization of O-ring failure risks
• Requires attention from business concept to implementation
• What information do these users want to see ?
• How does this information support decision making ?
• How to visualize it with clarity yet powerfully ?

30.
DATA SCIENCE IN BUSINESS
• Data analysis in business is not the sole task of the data scientist
• The whole organization must gradually mature and engage data
• This is not a technical barrier, it is a human barrier
• How to design business and social processes to employ data?
• Average business has tons of low-hanging data fruit
• Developing and automating all that takes years (and years)
• No use for advanced modeling without visibility to the underlying

31.
WHAT’S COMING UP

32.
PROCESSING DATA IN THE FUTURE
• The event stream itself is increasingly becoming the master input data for
analytics and data solutions
• This is a big sea change, requiring new designs of storage and processing
• Seeing the full timeline and interactions of each object is a mixed blessing
PROS Huge opportunity for discovering significant value
CONS A very complex haystack, needs additional processing, how can a human
focus on the essential?

33.
STREAM PROCESSING
• Instead of handling static states of the data, the data is processed
as it enters the system
• Tables turn: the internal state of the stream persisted to a database
becomes now the backup for failure occasions
• Obvious fit for quickly reactive online learning solutions
• The whole domain was spearheaded by computer trading
• Another example: credit card transaction processing and fraud prevention

34.
HADOOP AND DATA SCIENCE
• Hadoop is a general service platform, not just a MapReduce engine
• HBase is already becoming a hugely popular service backend
• In the long run Hadoop will also host a successful analytic database
• A wide selection of very different approaches to analytics and data science
exists already:
Hive and Pig, Impala, Mahout, Vowpal Wabbit, DataFu, Cloudera ML,
Giraph, RHadoop, …

35.
REARRANGING THE MAP
• Change is not driven by replacing current bad solutions, but by innovating
around their shortcomings
• Stream processing of data will capture a large corner, driven by a sweeping
push closer to real-time
• High-level functional interfaces to data another winner
• Examples: Cascading for batch processing, Trident for stream processing
• Further innovation in fixing MapReduce shortcomings
• Examples: Spark and Shark for iterative tasks, Impala for analytics

36.
THE END