# Functional Analysis

Video Activity
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Time
5 hours 58 minutes
Difficulty
Intermediate
CEU/CPE
6
Video Transcription
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>> Welcome back to Cybrary's ISSEP course,
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In this lesson, we're going to define
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functional analysis what it is,
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we're going to talk about the basic parts,
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and then we're going to talk real briefly about
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a functional diagram and what that leads us to.
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Functional analysis pretty straightforward as an SE,
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that's where we take requirements and translate them
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into the functions and criteria that
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we need for systems development.
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From a systems engineering perspective
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and a system security engineering perspective,
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we're taking the requirements and we're putting them into
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bins and those bins allow us to frame out
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what the system actually needs to do functionally,
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and then we create
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the requirements that we're actually going to test to.
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The basics of
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functional analysis is pretty straightforward.
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We look at concepts and alternatives.
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We want to have different options because
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not every requirement has to be a technical solution.
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We're going to create those hierarchies of the framework.
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We're going to say, "Okay, this is
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the starting point of bin 1
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under bin 1." We're going to frame out.
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"Here's the eight different things
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that need to be done to
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make sure that that function is completed."
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We're going to do modeling and
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decomposition. This is really important.
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If we don't model what
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we want the system to be as an engineer,
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then the system isn't going to behave that way.
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Same thing with decomposition.
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We have to take all the tasks and
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activities and we have to think like a user,
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we have to do that true engineering work to figure
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out are the functions going to work as designed?
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We're going to do both top down design
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and bottom up verification.
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When we do top down design,
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that means we say, "Okay,
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as a top level down to the next sub-levels,
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sub-level, sub-level, what does the system need to do?"
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Then we're going to stop and we're going to put on
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our builder hat our engineer hat,
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and we're going to work our way back up to the
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top to see if that makes sense.
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Ultimately, we're breaking down higher functions into
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lower-level functionalities to ensure
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that all the components are allocated to functions.
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Here's a functional diagram.
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As you can see here, it's pretty straightforward.
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It's really not rocket science.
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Here's our top-level function.
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We have sub-functions and then we have
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sub functions that allow us to map out what
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needs to be completed to ensure
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a function which is usually
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a complex piece or module of a system gets done.
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What are we really building here?
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We're really building the work breakdown structure
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for a system so that we could actually take
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these functions and these different requirements and
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hand them to a builder or
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developer and they could build it.
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Ultimately, what is the WBS?
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It is our product-oriented description of items,
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of things, of stuff that needs to be built,
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whether it's for the system engineers or for
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the information system security engineers or whatever
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specialty engineering needs to occur to
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ensure the function of a system in this particular case.
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In this video, we talked about functional analysis,
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we defined it, we looked at
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the basics of a functional analysis,
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and we talked about the creation of a functional diagram,
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