Information Technology Reference
In-Depth Information
1. If the new description contains parts ref-
erencing new files, add the corresponding
description parts to the current description.
2. Skip those parts that exist in both the new
and the current description and describe the
same behaviour.
3. Modify those parts of the current description
that exist in the new description, but describe
different behaviours.
a. If two sections of the part intersect
according to the relative file positions,
make a new section, which describes
the intersection of the two sections.
b. If the two intersecting sections are ran-
dom, the new section will be random.
c. If the two sections are sequential with
the same directions, the new section
will also be sequential.
d. If the two sections are sequential with
opposite directions, the new section
will be random.
e. If one of the sections is sequential
and the other one is random, then the
derived section will be random.
this, the execution frequencies (weights) of the
paths are also registered giving the probability of
their execution.
The new complex job description must provide
a more precise (compared to the
simple
job descrip-
tion) however non-redundant representation of the
CFG of the job. In our case, redundancy means
that the member job descriptions of the
composed
job description
have to give significantly different
completion time estimates. In order to generate
the desired precise non-redundant composed job
description:
1. the new job description is inserted into the
old composed description, or
2. a similar job description is replaced by the
new job description, or
3. the old composed job description is used.
The
similarity
of the new job description and
the members of the old complex description de-
termine which method is used to create the new
job description. The similarity measure of the
member job descriptions must be higher than a
certain
threshold
value (i.e. the composed descrip-
tion cannot contain similar member descriptions).
After calculating the similarity of the newly
generated individual job description (reflecting the
behaviour of the job during its latest execution)
and the member job descriptions, the complex
job description is updated in the following way:
The attributes of the derived sections will
comply with those of the originator sections. For
example, if the originator sections are random,
then the access_ratio of the derived section is
the average of the access_ratio of the originator
random sections.
This technique results in job descriptions that
reflect the already visited control paths of a given
job. However, the resulting description is globally
less precise, as it is not able to give close descrip-
tions of the individual control paths.
1. If the distances between the individual job
description and the member job descriptions
are greater than the threshold then the new
description is
inserted
into the composed
description. The absolute weight of the new
member description will be 1.
2. If there is a member job description, which
is closer to the new individual description
than the similarity threshold value, but the
diversity of the member descriptions would
increase with the insertion of the new descrip-
tion, then the new description
replaces
the
Multiple Descriptions
Instead of using the latest individual job descrip-
tion, according to the
multiple descriptions
ap-
proach, a complex and detailed job description
is created by collecting
simple job descriptions
relating to different paths in the job's CFG. Besides
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