Information Technology Reference
In-Depth Information
In principle we could use this, plus
the Dictionaries in order to
understand the keywords in order
to extract the numbers
If we can run this then we can use
this in a generic application to
extract the numbers
FITS FILE
FITS
STANDARD
FITS
DICTIONARY
DDL
DESCRIPTION
If we cannot run the Java
Virtual Machine then we use
this source code to re-write in
another programming
language such as C
DDL
SOFTWARE
FITS JAVA
SOFTWARE
PDF
STANDARD
DICTIONARY
SPECIFICATION
DDL
DEFINITION
JAVA VM
PDF
SOFTWARE
XML
SPECIFICATION
UNICODE
SPECIFICATION
If we can run this then we can run
the Java software to extract the numbers
If we cannot run the DDL software
then we can look at the DDL
definition and write some software
to extract the numbers
If we cannot run this then we can
use an emulator or use its RepInfo
to re-create a Java VM
Fig. 9.2
Using the representation information network in the extraction of information from
digitally encoded information (FITS file)
the data. Of course this RIN will also let us know which version of Java is needed
and so forth. If the user can run the Java application then it is a simple matter to
extract the number.
Other options include:
A.
if (s)he does not have the correct version of Java at hand then (s)he at least has
the option of trying to obtain it from another Registry/Repository - because (s)he
knows what is needed.
a. An important variant of this is the use of emulators, described in
Sect. 7.9
.
B.
if the Java application cannot be run then it might be possible to take the Java
source code, if available, and convert it to some programming language, say the
C programming language, from which one can create an appropriate application.
C.
if neither (A) nor (B) are possible, then a data description language (DDL) such
as EAST or DRB, together with the associated data dictionary, may be used.
Again there are a number of possibilities.
a. The easiest is that a generic application such as the one described in
Sect. 7.3.5
can use the data description to extract the information needed.
b. Otherwise one might have to read the DDL description, together with the
definition of that DDL, and the associated Data Dictionary or other piece of
