On 8/30/14 1:35 PM, Kingsley Idehen
wrote:
On 8/29/14 5:27
PM, Hans Polzer wrote:
Patrik,
One major issue with Big Data (and any data, for that
matter) is the issue of the scope of the data sets,
which is usually left implicit and often inferred from
external knowledge about the data source. By scope of
the data sets I mean what portion of reality does the
data set purport to represent. Sometimes the
complexity of the data representation in a data set is
due to explicit inclusion of scope information, but
usually scope is left unspecified in the data
representation.
For example, if one is trying to determine air traffic
patterns from data sets provided by the various
national/regional air traffic authorities or airlines,
aside from all the differences in representation and
complexity of such data by the different sources, one
has to determine what portion of the overall air
traffic is captured by the aggregate sources one has
access to, and whether there is any overlap among the
sources (and what the nature of the overlap might
signify with respect to one's objective for accessing
the data sources). Do some of the sources include
general aviation traffic or only scheduled commercial
(passenger?) traffic. What portion of the world's air
traffic (of a particular set of types) do we not have
data sources for? Are the time ranges of the data
sources compatible with the data access objectives?
Does a particular source include military aircraft
traffic? Does it include charters. Does it include
Government executive aircraft?
What about helicopter traffic or lighter than air
traffic or UAVs? Up and down to what vehicle size
ranges? What about sub-orbital or orbital traffic
(even if one excludes "space" traffic as not being
"air" traffic, space and orbital traffic typically
traverses the atmosphere when launched and often
returns through the atmosphere)? Are hovercraft
considered air traffic? What about gliders,
paragliders, and "airsuits", or are we only interested
in powered aircraft or fuel-burning aircraft (not all
powered craft burn fuel)? Note that there are
fuel-burning paragliders. Are rockets/missiles and
artillery considered "air" traffic?
When one accesses Big Data for some purpose, what has
one really accessed?
Data distorted by qualification using a meaningless
buzz-phrase
How
big is "Big"?
Reinforcing my comment above.
More
importantly, how big a portion of what one is looking
for does Big Data represent?
Ditto.
And
what can one safely conclude for the purposes at hand,
given that scope information (assuming it is available
or can be inferred)? I'm not sure this is totally a
question of logic.
Correct, it is inevitably illogical. Thanks to the
meaningless nature of a classic marketing buzz-phrase
[1].
## Nanotation Start ##
<https://twitter.com/hashtag/Buzzword#this>
a skos:Concept ;
owl:sameAs <http://dbpedia.org/resource/Buzzword>
;
is foaf:primaryTopic of <http://dbpedia.org/describe/?url="">
.
## Nanotation End ##
Links:
[1] https://twitter.com/kidehen/status/492757872816971776
-- What is a buzzword or buzz-phrase ?
Hans Polzer
In regards to Air Traffic Control data, I found an ontology from
NASA, and then tweaked it with these SPARQL statements:
## Air Traffic Control Ontology
# URI: <http://cdm.arc.nasa.gov/tfm.owl#>
# URL: <http://ti.arc.nasa.gov/m/profile/shawn/tfmontology/tfmBJ1.owl>
INSERT
{GRAPH <http://cdm.arc.nasa.gov/tfm.owl>
{
?s rdfs:isDefinedBy <http://cdm.arc.nasa.gov/tfm.owl#>
.
<http://cdm.arc.nasa.gov/tfm.owl#>
<http://open.vocab.org/terms/defines>
?s.
<http://cdm.arc.nasa.gov/tfm.owl#>
a owl:Ontology .
?s <http://www.w3.org/2007/05/powder-s#describedby>
<http://ti.arc.nasa.gov/m/profile/shawn/tfmontology/tfmBJ1.owl>
.
<http://ti.arc.nasa.gov/m/profile/shawn/tfmontology/tfmBJ1.owl>
<http://open.vocab.org/terms/describes>
?s .
}
}
WHERE
{GRAPH <http://ti.arc.nasa.gov/m/profile/shawn/tfmontology/tfmBJ1.owl>
{
{?s rdfs:subClassOf ?o}
UNION
{?s rdfs:subPropertyOf ?o}
UNION
{?s owl:equivalentClass ?o}
UNION
{?s owl:equivalentProperty ?o}
UNION
{?s a ?o}
}
}
End product:
[1] http://linkeddata.uriburner.com/c/8BPYQ5
-- Tweaked (for easy navigation and exploration) Air Traffic Control
Ontology
[2] http://linkeddata.uriburner.com/c/9C6PQJ35
-- A Class from the Ontology .
--
Regards,
Kingsley Idehen
Founder & CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog 1: http://kidehen.blogspot.com
Personal Weblog 2: http://www.openlinksw.com/blog/~kidehen
Twitter Profile: https://twitter.com/kidehen
Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen
Personal WebID: http://kingsley.idehen.net/dataspace/person/kidehen#this
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