Software engineering -test 1-(part 5)
GQM is broken down into three levels:
1.Goals (conceptual level)
2. Questions (operational level)
3. Metrics (quantitative level)
Steps in GQM Method
1. Goals are defined and described clearly.
2. Conversion of goals into appropriate questions.
3. Questions are transformed into metrics.
There are four levels of measurement (or scales) in measuring GQM.
Nominal level
Ordinal Level
Interval Level
Ratio Level
Nominal level
The nominal scale simply categorizes variables according to qualitative labels (or names). These labels and
groupings don’t have any order or hierarchy to them, nor do they convey any numerical value
Ordinal Level
The ordinal scale also categorizes variables into labeled groups, and these categories have an order or
hierarchy to them.
Examples include status at workplace, tournament team rankings, order of product quality, and order of
agreement or satisfaction etc.
Interval Level
The interval scale is a numerical scale which labels and orders variables, with a known, evenly spaced
interval between each of the values.
Example, You can categorize, rank, and infer equal intervals between neighboring data points, but there
is no true zero point
Ratio Level
The ratio scale is exactly the same as the interval scale, with one key difference: The ratio scale has
what’s known as a “true zero.”
A true zero means there is an absence of the variable of interest. In ratio scales, zero does mean an
absolute lack of the variable.
For example, in the Kelvin temperature scale, there are no negative degrees of temperature – zero means
an absolute lack of thermal energy. Also includes Height, Age, Weight etc
Steps in GQM Method
1. Goals are defined and described clearly.
2. Conversion of goals into appropriate questions.
3. Questions are transformed into metrics.
Complexity (Breadth)
More functionalities
More features within each functionality
More interfaces and linkages to other components or to other external systems
More users and varieties of users
More data, varieties of data, data structures
Complexity (Depth) (number of interactions)
More linkages and connections
Data sharing among the functionalities and logic
Control passing among functionalities
Nested loops among logic
Multiple hierarchical levels among functions (the number of levels of the hierarchy )
The simple case figure (a) has three major segments
(1) start process
(2) perform three normal tasks, and
(3) stop process.
DECOMPOSITION
The power of computational thinking starts with
decomposition, which is the process of breaking
down complex problems into smaller, more
manageable parts. With decomposition, problems
that seem overwhelming at first become much more
manageable
MODULARIZATION
Modularization is the process of separating the functionality
of a program into independent, interchangeable modules,
such that each contains everything necessary to execute
only one aspect of the desired functionality.
Consider an example, we all have been playing Legos to build
different structures. Here we have several components i.e.,
blocks which we integrate to build the structure that we want
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Incremental
An incremental approach breaks the software development process down into small,
manageable portions known as increments. Each increment builds on the previous version so that
improvements are made step by step.
Iterative
An iterative model means software development activities are systematically repeated in
cycles known as iterations. A new version of the software is produced after each iteration until the optimal
product is achieved.