Title: Where The Rubber Meets the Sky Giving Access to Science Data
1Where The Rubber Meets the SkyGiving Access to
Science Data
- Jim Gray
- Microsoft Research
- Gray_at_Microsoft.com
- Http//research.Microsoft.com/Gray
- Alex SzalayJohns Hopkins University
- Szalay_at_JHU.edu
- Talk at
- 16th International Conference on
- Scientific and Statistical Database Management
- June 2004, Santorini, Greece
2- Promised Abstract Historically, scientists
gatherer and analyzed their own data. But
technology has created functional specialization
where some scientists gather or generate data,
and others analyze it. Technology allows us to
easily capture vast amounts of empirical data
and to generate vast amounts of simulated data.
Technology also allows us to store these bytes
almost indefinitely. But there are few tools to
organize scientific data for easy access and
query, few tools to curate the data, and few
tools to federate science archives. Domain
scientists, notably NCBI and the Virtual
Observatory, are making heroic efforts to address
these problems. But this is a generic problem
that cuts across all scientific disciplines. It
requires a coordinated effort by the computer
science community to build generic tools that
will help all the sciences. Our current
database products are a start, but much more is
needed. - Actual Abstract
- I have been working with Alex Szalay and other
astronomers for the last 6 years trying to apply
DB technology to science problems. - These are some lessons I learned.
3Outline
- New Science
- X-Info for all fields X
- WWT as an example
- Big Picture
- Puzzle
- Hitting the wall
- Needle in haystack
- Mohamed and the mountain
- Working cross disciplines
- Data Demographics and Data Handling
- Curation
4New Science Paradigms
- Thousand years ago science was empirical
- describing natural phenomena
- Last few hundred years theoretical branch
- using models, generalizations
- Last few decades a computational branch
- simulating complex phenomena
- Today data exploration (eScience)
- unify theory, experiment, and simulation
- using data management and statistics
- Data captured by instrumentsOr generated by
simulator - Processed by software
- Scientist analyzes database / files
5The Virtual Observatory
- Premise most data is (or could be online)
- The Internet is the worlds best telescope
- It has data on every part of the sky
- In every measured spectral band optical, x-ray,
radio.. - As deep as the best instruments (2 years ago).
- It is up when you are up
- The seeing is always great
- Its a smart telescope links objects and
data to literature - Software is the capital expense
- Share, standardize, reuse..
6Why Is Astronomy Special?
- Almost all literature online and public ADS
http//adswww.harvard.edu/ CDS
http//cdsweb.u-strasbg.fr/ - Data has no commercial value
- No privacy concerns, freely share results with
others - Great for experimenting with algorithms
- It is real and well documented
- High-dimensional (with confidence intervals)
- Spatial, temporal
- Diverse and distributed
- Many different instruments from many different
places and many different times - The community wants to share the data
- There is a lot of it (soon petabytes)
7The Big Picture
The Big Problems
- Data ingest
- Managing a petabyte
- Common schema
- How to organize it?
- How to reorganize it?
- How to coexist with others?
- Data Query and Visualization tools
- Support/training
- Performance
- Execute queries in a minute
- Batch (big) query scheduling
8What X-info Needs from us (cs)(not drawn to
scale)
9Experiment Budgets ¼½ Software
- Millions of lines of code
- Repeated for experiment after experiment
- Not much sharing or learning
- Lets work to change this
- Identify generic tools
- Workflow schedulers
- Databases and libraries
- Analysis packages
- Visualizers
- Software for
- Instrument scheduling
- Instrument control
- Data gathering
- Data reduction
- Database
- Analysis
- Visualization
Simulation (computational science) are gt ½
software
10Data Access Hitting a Wall
- Current science practice based on data download
(FTP/GREP)Will not scale to the datasets of
tomorrow - You can GREP 1 MB in a second
- You can GREP 1 GB in a minute
- You can GREP 1 TB in 2 days
- You can GREP 1 PB in 3 years.
- Oh!, and 1PB 5,000 disks
- At some point you need indices to limit
search parallel data search and analysis - This is where databases can help
- You can FTP 1 MB in 1 sec
- You can FTP 1 GB / min (1)
- 2 days and 1K
- 3 years and 1M
11Next-Generation Data Analysis
- Looking for
- Needles in haystacks the Higgs particle
- Haystacks dark matter, dark energy, turbulence,
ecosystem dynamics - Needles are easier than haystacks
- Global statistics have poor scaling
- Correlation functions are N2, likelihood
techniques N3 - As data and computers grow at Moores Law, we
can only keep up with N logN - A way out?
- Relax optimal notion (data is fuzzy, answers are
approximate) - Dont assume infinite computational resources or
memory - Requires combination of statistics computer
science
12Smart Data Unifying DB and Analysis
- There is too much data to move aroundDo data
manipulations at database - Build custom procedures and functions into DB
- Unify data Access Analysis
- Examples
- Statistical sampling and analysis
- Temporal and spatial indexing
- Pixel processing
- Automatic parallelism
- Auto (re)organize
- Scalable to Petabyte datasets
-
Move Mohamed to the mountain, not the mountain to
Mohamed.
13Outline
- New Science
- Working cross disciplines
- How to help?
- 20 questions
- WWT example
- Alternative CS Process Models
- Data Demographics and Data Handling
- Curation
14How to Help?
- Cant learn the discipline before you
start(takes 4 years.) - Cant go native you are a CS person not a
bio, person - Have to learn how to communicateHave to learn
the language - Have to form a working relationship with domain
expert(s) - Have to find problems that leverage your skills
15Working Cross-Culture A Way to Engage With
Domain Scientists
- Communicate in terms of scenarios
- Work on a problem that gives 100x benefit
- Weeks/task vs hours/task
- Solve 20 of the problem
- The other 80 will take decades
- Prototype
- Go from working-to-working, Always have
- Something to show
- Clear next steps
- Clear goal
- Avoid death-by-collaboration-meetings.
16Working Cross-Culture -- 20 Questions A Way to
Engage With Domain Scientists
- Astronomers proposed 20 questions
- Typical of things they want to do
- Each would require a week or more in old way
(programming in tcl / C/ FTP) - Goal, make it easy to answer questions
- This goal motivates DB and tools design
17The 20 Queries
- Q11 Find all elliptical galaxies with spectra
that have an anomalous emission line. - Q12 Create a grided count of galaxies with u-ggt1
and rlt21.5 over 60ltdeclinationlt70, and 200ltright
ascensionlt210, on a grid of 2, and create a map
of masks over the same grid. - Q13 Create a count of galaxies for each of the
HTM triangles which satisfy a certain color cut,
like 0.7u-0.5g-0.2ilt1.25 rlt21.75, output it in
a form adequate for visualization. - Q14 Find stars with multiple measurements and
have magnitude variations gt0.1. Scan for stars
that have a secondary object (observed at a
different time) and compare their magnitudes. - Q15 Provide a list of moving objects consistent
with an asteroid. - Q16 Find all objects similar to the colors of a
quasar at 5.5ltredshiftlt6.5. - Q17 Find binary stars where at least one of them
has the colors of a white dwarf. - Q18 Find all objects within 30 arcseconds of one
another that have very similar colors that is
where the color ratios u-g, g-r, r-I are less
than 0.05m. - Q19 Find quasars with a broad absorption line in
their spectra and at least one galaxy within 10
arcseconds. Return both the quasars and the
galaxies. - Q20 For each galaxy in the BCG data set
(brightest color galaxy), in 160ltright
ascensionlt170, -25ltdeclinationlt35 count of
galaxies within 30"of it that have a photoz
within 0.05 of that galaxy.
- Q1 Find all galaxies without unsaturated pixels
within 1' of a given point of ra75.327,
dec21.023 - Q2 Find all galaxies with blue surface
brightness between and 23 and 25 mag per square
arcseconds, and -10ltsuper galactic latitude (sgb)
lt10, and declination less than zero. - Q3 Find all galaxies brighter than magnitude 22,
where the local extinction is gt0.75. - Q4 Find galaxies with an isophotal surface
brightness (SB) larger than 24 in the red band,
with an ellipticitygt0.5, and with the major axis
of the ellipse having a declination of between
30 and 60arc seconds. - Q5 Find all galaxies with a deVaucouleours
profile (r¼ falloff of intensity on disk) and the
photometric colors consistent with an elliptical
galaxy. The deVaucouleours profile - Q6 Find galaxies that are blended with a star,
output the deblended galaxy magnitudes. - Q7 Provide a list of star-like objects that are
1 rare. - Q8 Find all objects with unclassified spectra.
- Q9 Find quasars with a line width gt2000 km/s and
2.5ltredshiftlt2.7. - Q10 Find galaxies with spectra that have an
equivalent width in Ha gt40Å (Ha is the main
hydrogen spectral line.)
Also some good queries at http//www.sdss.jhu.edu
/ScienceArchive/sxqt/sxQT/Example_Queries.html
18Two kinds of SDSS data in an SQL DB(objects and
images all in DB)
- 300M Photo Objects 400 attributes
- 10B rows overall
400K Spectra with 30
lines/ Spectrum 100 M rows
19An easy one Q7 Provide a list of star-like
objects that are 1 rare.
- Found 14,681 buckets, first 140 buckets have
99 time 104 seconds - Disk bound, reads 3 disks at 68 MBps.
Select cast((u-g) as int) as ug, cast((g-r) as
int) as gr, cast((r-i) as int) as ri,
cast((i-z) as int) as iz, count()
as Population from stars group by cast((u-g) as
int), cast((g-r) as int), cast((r-i) as int),
cast((i-z) as int) order by count()
20Then What?
- 20 Queries were a way to engage
- Needed spatial data library
- Needed DB design
- Built website to publish the data
- Data Loading (workflow scheduler).
- Pixel web service evolved to
- SkyQuery federation evolved to
- Now focused on spatial data library.
Conversion to OR DB (put analysis in DB).
21Alternate Model
- Many sciences are becoming information
sciences - Modeling systems needs new and better
languages. - CS modeling tools can help
- Bio, Eco, Linguistic,
- This is the process/program centric view rather
than my info-centric view.
22Outline
- New Science
- Working cross disciplines
- Data Demographics and Data Handling
- Exponential growth
- Data Lifecycle
- Versions
- Data inflation
- Year 5
- Overprovision by 6x
- Data Loading
- Regression Tests
- Statistical subset
- Curation
23Information Avalanche
- In science, industry, government,.
- better observational instruments and
- and, better simulations
- producing a data avalanche
- Examples
- BaBar Grows 1TB/day 2/3 simulation Information
1/3 observational Information - CERN LHC will generate 1GB/s .10 PB/y
- VLBA (NRAO) generates 1GB/s today
- Pixar 100 TB/Movie
- New emphasis on informatics
- Capturing, Organizing, Summarizing, Analyzing,
Visualizing
Image courtesy C. Meneveau A. Szalay _at_ JHU
BaBar, Stanford
PE Gene Sequencer From http//www.genome.uci.edu/
Space Telescope
24Q Where will the Data Come From?A Sensor
Applications
- Earth Observation
- 15 PB by 2007
- Medical Images Information Health Monitoring
- Potential 1 GB/patient/y ? 1 EB/y
- Video Monitoring
- 1E8 video cameras _at_ 1E5 MBps ? 10TB/s ? 100
EB/y ? filtered??? - Airplane Engines
- 1 GB sensor data/flight,
- 100,000 engine hours/day
- 30PB/y
- Smart Dust ?? EB/y
http//robotics.eecs.berkeley.edu/pister/SmartDus
t/
http//www-bsac.eecs.berkeley.edu/shollar/macro_m
otes/macromotes.html
25Instruments CERN LHCPeta Bytes per Year
- Looking for the Higgs Particle
- Sensors 1 GB/s ( 20 PB/y)
- Events 100 MB/s
- Filtered 10 MB/s
- Reduced 1 MB/s Data pyramid 100GB
1TB 100TB 1PB 10PB
26Like all sciences, Astronomy Faces an
Information Avalanche
- Astronomers have a few hundred TB now
- 1 pixel (byte) / sq arc second 4TB
- Multi-spectral, temporal, ? 1PB
- They mine it looking for new (kinds of) objects
or more of interesting ones (quasars),
density variations in 400-D space correlations
in 400-D space - Data doubles every year
- Data is public after 1 year
- So, 50 of the data is public
- Same access for everyone
27Moores Law in Proteomics
Courtesy of Peter Berndt, Roche Center for
Medical Genomics (RCMG)
- Roche Center for Medical Genomics (RCMG) number
of mass-spectra acquired for proteomics doubled
every year since first mass spectrometer
deployed.
R20.96
28Data Lifecycle
- Raw data ? primary data ? derived data
- Data has bugs
- Instrument bugs
- Pipeline bugs
- Data comes in versions
- later versions fix known bugs
- Just like software (indeed data is software)
- Cant un-publish bad data.
29Data Inflation Data Pyramid
- Level 2Derived data products 10x smaller But
there are many. L2L1 - Publish new edition each year
- Fixes bugs in data.
- Must preserve old editions
- Creates data pyramid
- Store each edition
- 1, 2, 3, 4 N N2 bytes
- Net Data Inflation L2 L1
- Level 1AGrows X TB/year .4X TB/y
compressed (level 1A in NASA terms)
30The Year 5 Problem
- Data arrives at R bytes/year
- New Storage Processing
- Need to buy R units in year N
- Data inflation means N2R
- Need to buy NR units
- Depreciate over 3 years
- After year 3 need to buy N2R (N-3)2R
- Moores law 60/year price decline
- Capital expense peaks at year 5
- See 6x Over-Power slide next
316x Over-Power Ratio
- If you think you need X raw capacity, then you
probably need 6X - Reprocessing
- Backup copies
- Versions
-
- Hardware is cheap, Your time is precious.
32Data Loading
- Data from outside
- Is full of bugs
- Is not in your format
- Advice
- Get it in a Universal Format (e.g. Unicode
CSV) - Create Blood-Brain barrier Quarantine in a
load database - Scrub the data
- Cross check everything you can
- Check data statistics for sanity
- Reject or repair bad data
- Generate detailed bug reports(needed to send
rejection upstream) - Expect to reload many times Automate everything!
33Performance Prediction Regression
- Database grows exponentially
- Set up response-time requirements
- For load
- For access
- Define a workload to measure each
- Run it regularly to detect anomalies
- SDSS uses
- one-week to reload
- 20 queries with response of 10 sec to 10 min.
34Data Subsets For Science and Development
- Offer 1GB, 10GB, , Full subsets
- Wonderful tool for you
- Debug algorithms
- Good tool for scientists
- Experiment on subset
- Not for needle in haystack, but good for global
stats - Challenge How make statistically valid subsets?
- Seems domain specific
- Seems problem specific
- But, must be some general concepts.
35Outline
- New Science
- Working cross disciplines
- Data Demographics and Data Handling
- Curation
- Problem statement
- Economics
- Astro as a case in point
36Problem Statement
- Once published, scientific data needs to be
available forever,so that the science can be
reproduced/extended. - What does that mean?
- Data can be characterized as
- Primary Data could not be reproduced
- Derived data could be derived from primary data.
- Meta-data how the data was collected/derivedis
primary - Must be preserved
- Includes design docs, software, email, pubs,
personal notes, teleconferences,
NASA level 0
37The Core Problem No Economic Model
- The archive user is not yet born. How can he
pay you to curate the data? - The Scientist gathered data for his own
purposeWhy should he pay (invest time) for your
needs? - Answer to both thats the scientific method
- Curating data (documenting the design, the
acquisition and the processing)Is difficult and
there is little reward for doing it.Results are
rewarded, not the process of getting them. - Storage/archive NOT the problem (its almost
free) - Curating/Publishing is expensive,MAKE IT
EASIER!!! (lower the cost)
38Publishing Data
Roles Authors Publishers Curators Archives Consume
rs
Traditional Scientists Journals Libraries Archives
Scientists
Emerging Collaborations Project web site DataDoc
Archives Digital Archives Scientists
39Changing Roles
- Exponential growth
- Projects last at least 3-5 years
- Project data online during project lifetime.
- Data sent to central archive only at the end of
the project - At any instant, only 1/8 of data is in central
archives - New project responsibilities
- Becoming Publishers and Curators
- Larger fraction of budget spent on software
- Standards are needed
- Easier data interchange, fewer tools
- Templates are needed
- Much development duplicated, wasted
40What SDSS is Doing Capture the Bits(preserve
the primary data)
- Best-effort documenting data and
processDocuments and data are hyperlinked. - Publishing data often by UPS( 5TB today and so
5k for a copy) - Replicating data on 3 continents.
- EVERYTHING online (tape data is dead data)
- Archiving all email, discussions, .
- Keeping all web-logs query logs.
- Now we need to figure out how to organize/search
all this metadata.
41Schema (aka metadata)
- Everyone starts with the same schema
ltstuff/gtThen the start arguing about semantics. - Virtual Observatory http//www.ivoa.net/
- Metadata based on Dublin Corehttp//www.ivoa.net
/Documents/latest/RM.html - Universal Content Descriptors (UCD)
http//vizier.u-strasbg.fr/doc/UCD.htxCaptures
quantitative concepts and their unitsReduced
from 100,000 tables in literature to 1,000
terms - VOtable a schema for answers to
questionshttp//www.us-vo.org/VOTable/ - Common QueriesCone Search and Simple Image
Access Protocol, SQL - Registry http//www.ivoa.net/Documents/latest/RME
xp.htmlstill a work in progress.
42Summary
- New Science
- X-Info for all fields X
- WWT as an example
- Big Picture
- Puzzle
- Hitting the wall
- Needle in haystack
- Move queries to data
- Working cross disciplines
- How to help?
- 20 questions
- WWT example
- Alt CS Process Models
- Data Demographics
- Exponential growth
- Data Lifecycle
- Versions
- Data inflation
- Year 5 is peak cost
- Overprovision by 6x
- Data Loading
- Regression Tests
- Statistical subset
- Curation
- Problem statement
- Economics
- Astro as a case in point
43Call to Action
- X-info is emerging.
- Computer Scientists can help in many ways.
- Tools
- Concepts
- Provide technology consulting to the community
- There are great CS research problems here
- Modeling
- Analysis
- Visualization
- Architecture
44References http//SkyServer.SDSS.org/http//rese
arch.microsoft.com/pubs/ http//research.microsof
t.com/Gray/SDSS/ (download personal SkyServer)
- Extending the SDSS Batch Query System to the
National Virtual Observatory Grid, M. A.
Nieto-Santisteban, W. O'Mullane, J. Gray, N. Li,
T. Budavari, A. S. Szalay, A. R. Thakar,
MSR-TR-2004-12, Feb. 2004 - Scientific Data Federation, J. Gray, A. S.
Szalay, The Grid 2 Blueprint for a New Computing
Infrastructure, I. Foster, C. Kesselman, eds,
Morgan Kauffman, 2003, pp 95-108. - Data Mining the SDSS SkyServer Database, J.
Gray, A.S. Szalay, A. Thakar, P. Kunszt, C.
Stoughton, D. Slutz, J. vandenBerg, Distributed
Data Structures 4 Records of the 4th
International Meeting, pp 189-210, W. Litwin, G.
Levy (eds),, Carleton Scientific 2003, ISBN
1-894145-13-5, also MSR-TR-2002-01, Jan. 2002 - Petabyte Scale Data Mining Dream or Reality?,
Alexander S. Szalay Jim Gray Jan vandenBerg,
SIPE Astronomy Telescopes and Instruments, 22-28
August 2002, Waikoloa, Hawaii, MSR-TR-2002-84 - Online Scientific Data Curation, Publication,
and Archiving, J. Gray A. S. Szalay A.R.
Thakar C. Stoughton J. vandenBerg, SPIE
Astronomy Telescopes and Instruments, 22-28
August 2002, Waikoloa, Hawaii, MSR-TR-2002-74 - The World Wide Telescope An Archetype for Online
Science, J. Gray A. Szalay,, CACM, Vol. 45, No.
11, pp 50-54, Nov. 2002, MSR TR 2002-75, - The SDSS SkyServer Public Access To The Sloan
Digital Sky Server Data, A. S. Szalay, J. Gray,
A. Thakar, P. Z. Kunszt, T. Malik, J. Raddick, C.
Stoughton, J. vandenBerg, ACM SIGMOD 2002
570-581 MSR TR 2001 104. - The World Wide Telescope, A.S., Szalay, J.,
Gray, Science, V.293 pp. 2037-2038. 14 Sept 2001.
MS-TR-2001-77 - Designing Mining Multi-Terabyte Astronomy
Archives Sloan Digital Sky Survey, A. Szalay,
P. Kunszt, A. Thakar, J. Gray, D. Slutz, P.
Kuntz, June 1999, ACM SIGMOD 2000, MS-TR-99-30,
45(No Transcript)
46(No Transcript)
47How to Publish Data Web Services
- Web SERVER
- Given a url parameters
- Returns a web page (often dynamic)
- Web SERVICE
- Given a XML document (soap msg)
- Returns an XML document (with schema)
- Tools make this look like an RPC.
- F(x,y,z) returns (u, v, w)
- Distributed objects for the web.
- naming, discovery, security,..
- Internet-scale distributed computing
Your program
Web Server
http
Web page
Your program
Web Service
soap
Data In your address space
objectin xml
48Global Federations
- Massive datasets live near their owners
- Near the instruments software pipeline
- Near the applications
- Near data knowledge and curation
- Each Archive publishes a (web) service
- Schema documents the data
- Methods on objects (queries)
- Scientists get personalized extracts
- Uniform access to multiple Archives
- A common global schema
Federation
49The Sloan Digital Sky Survey
- Goal
- Create the most detailed map of the Northern Sky
to-date - 2.5m telescope
- 3 degree field of view
- Two surveys in one
- 5-color images of ¼ of the sky
- Spectroscopic survey of a million galaxies and
quasars - Very high data volume
- 40 Terabytes of raw data
- 10 Terabytes processed
- All data public
The University of Chicago Princeton
University The Johns Hopkins University The
University of Washington New Mexico State
University University of Pittsburgh Fermi
National Accelerator Laboratory US Naval
Observatory The Japanese Participation Group
The Institute for Advanced Study Max Planck
Inst, Heidelberg Sloan Foundation, NSF, DOE,
NASA
50SkyServer
- A multi-terabyte database
- An educational website
- More than 50 hours of educational exercises
- Background on astronomy
- Tutorials and documentation
- Searchable web pages
- Easy astronomer access to SDSS data.
- Prototype eScience lab
- Interactive visual tools for data exploration
http//skyserver.sdss.org/
51Demo SkyServer
- atlas
- education project
- Mouse in pixel space
- Explore an object (record space)
- Explore literature
- Explore a set
- Pose a new question
52SkyQuery (http//skyquery.net/)
- Distributed Query tool using a set of web
services - Many astronomy archives from Pasadena, Chicago,
Baltimore, Cambridge (England) - Has grown from 4 to 15 archives,now becoming
international standard - Allows queries like
SELECT o.objId, o.r, o.type, t.objId FROM
SDSSPhotoPrimary o, TWOMASSPhotoPrimary t
WHERE XMATCH(o,t)lt3.5 AND AREA(181.3,-0.76,6.5)
AND o.type3 and (o.I - t.m_j)gt2
53Demo SkyQuery Structure
- Portal is
- Plans Query (2 phase)
- Integrates answers
- Is itself a web service
- Each SkyNode publishes
- Schema Web Service
- Database Web Service
54MyDB eScience Workbench
- Prototype of bringing analysis to the data
- Everybody gets a workspace (database)
- Executes analysis at the data
- Store intermediate results there
- Long queries run in batch
- Results shared within groups
- Only fetch the final results
- Extremely successful matches work patterns
55National Center Biotechnology Information (NCBI)
A good Example
- PubMed
- Abstracts and books and..
- GenBank
- All Gene sequences deposited
- BLAST and other searches
- Website to explore data and literature
- Entrez
- unifies many databases with literature (books,
journals,..) - Organizes the data
56Making Discoveries
- Where are discoveries made?
- At the edges and boundaries
- Going deeper, collecting more data, using more
colors. - Metcalfes law quadratic benefit
- Utility of computer networks grows as the number
of possible connections O(N2) - Data Federation quadratic benefit
- Federation of N archives has utility O(N2)
- Possibilities for new discoveries grow as O(N2)
- Current sky surveys have proven this
- Very early discoveries from SDSS, 2MASS, DPOSS
57Global Federations
- Massive datasets live near their owners
- Near the instruments software pipeline
- Near the applications
- Near data knowledge and curation
- Each Archive publishes a (web) service
- Schema documents the data
- Methods on objects (queries)
- Scientists get personalized extracts
- Uniform access to multiple Archives
- A common global schema
Federation
58The OGIS model
Data Management
Producer
Ingest
Archive
Access
Consumer
Administer
59Jims Model of Library Science ?
- Alexandria
- Gutenberg
- (Melvil) Dewey Decimal
- MARC (Henriette Avram)
- Dublin Core
Yes, I know there have been other things.
60Dublin Core
- Elements
- Title
- Creator
- Subject
- Description
- Publisher
- Contributor
- Date
- Type
- Format
- Identifier
- Source
- Language
- Coverage
- Rights
- Elements
- Audience
- Alternative
- TableOfContents
- Abstract
- Created
- Valid
- Available
- Issued
- Modified
- Extent
- Medium
- IsVersionOf
- HasVersion
- IsReplacedBy
- Replaces
- IsRequiredBy
- Requires
- IsPartOf
- Encoding
- LCSH (Lb. Congress Subject Head)
- MESH (Medical Subject Head)
- DDC (Dewey Decimal Classification)
- LCC (Lb. Congress Classification)
- UDC (Universal Decimal Classification)
- DCMItype (Dublin Core Meta Type)
- IMT (Internet Media Type)
- ISO639-2 (ISO language names)
- RFC1766 (Internet Language tags)
- URI (Uniform Resource Locator)
- Point (DCMI spatial point)
- ISO3166 (ISO country codes)
- Box (DCMI rectangular area)
- TGN (Getty Thesaurus of Geo Names)
- Period (DCMI time interval)
- W3CDTF (W3C date/time)
- RFC3066 (Language dialects)
61Access Challenges
- Archived information rusts if it is not
accessed. Access is essential. - Access costs money who pays?
- Access sometimes uses IP, who pays?
- There are also technical problems
- Access formats are different from the storage
formats. - migration?
- emulation?
- Gold Standards?)
62Ingest Challenges
- Push vs Pull
- What are the gold standards?
- Automatic indexing, annotation, provenance.
- Auto-Migration (Format conversion)
- Version management
- How capture time varying sources
- Capture dark matter (encapsulated data)
- Bits dont rust but applications do.
63Archive Challenges
- Cost of administering storage
- Presently 10x to 100x the hardware cost.
- Resist attack geographic diversity
- At 1GBps it takes 12 days to move a PB
- Store it in two (or more) places online (on
disk). A geo-plex - Scrub it continuously (look for errors)
- On failure,
- use other copy until failure repaired,
- refresh lost copy from safe copy.
- Can organize the copies differently (e.g.
one by time, one by space)
64The Midrange Paradox
- Large archives are curated
- Curated by projects
- Small archives are appendices to papers
- Curated by journals
- Medium-sized archives are in limbo
- No place to register them
- No one has mandate to preserve them
- Example
- Your website with your data files
- Small scale science projects
- Genbank gets the sequence but not the software
or analysis that produced it.