Applying Quality Function Deployment to Software Development. ISQFD’99-Brazil Pre-conference Workshop 2. Professor Hisakazu Shindo Yamanashi University (Japan) [email protected] http://www.is.esi.yamanashi.ac.jp/~shindo/. Abstract.
QFD was proposed as a quality assurance methodology
in developing a new product.
Later, QFD has been introduced into various industries
such as manufacturing, construction, service, software, etc.
QFD applications to software development have been basically
carried out in the similar manner as employed in other fields.
Usually QFD starts with making a quality table consists of
requirements for quality and quality elements.
In software development, work of design said to be more
important than that of other fields because its quality is almost
determined by design itself.
development, a new methodology is required.
So, we must focus our attention on a
design-oriented aspect of QFD.
First, we consider two approaches to
Then, we re-recognize the significance of QFD.
Lastly, we propose a basic concept for applying
QFD to software development.
Two approaches to problem solving
Engineering and a two-dimensional table
An application of QFD to software development
“QC story”isa typical one.
QFD can be considered
as one of design-oriented approaches.
This is on the causality basis.
The process of asking “Why” many times
leads to problem solving.
A design-oriented approach
Satisfying a desire by realizing something to be made.
This is correspondent to work of design itself.
while QA activity is shifting from down stream
to up stream of a product development cycle.
We cannot help thinking about what design is.
Design is drawing or outline from which something
may be made.
Design is general arrangement or planning.
Design is pattern.
Design is purpose, intention, or mental plan.
(Engineering) drawing is the art of representing
objects, scenes, etc by lines, with a pencil, chalk, etc.
It consists of three
Everything shaped can be
designed in this way.
Analogy between drawing and a table
We know this is an automobile.
So we can express requirements
for quality with relative ease.
We don’t know what it is.
So we cannot express our
Applying QFD directly to a finished product,
the size of its quality table easily becomes large.
To reduce the size of the table, some people apply
QFD restrictedly to a subsystem or a part of the
However, it is a contradiction because the subsystem
or the part is determined after the design process
we should make it well-structured by any means.
Note that any two items of column and row are
allowed to exchange respectively. This operation
never violates the content of the table.
So, we can reduce the complexity of the table
by positively using this operation.
Quantification method of type three can be utilized.
about staff and their expertise.
Staff A has expertise concerning SPC and PC and
TQM is shared by staff C, D, E, F, and G.
we can obtain the following:
The result indicates staff can be
classified into four groups.
F x P
Quality F x Q
Reliability F x R
A new paradigm of applying QFD
Establishing basic concept of the product
Extracting major problems to be solved
Extracting major problems to be solved (Bottleneck engineering)
A B C D E
Technological viewpoint, Experiences, Knowledge, Tools
(1)Extract requirement for function and relevant data from
various kinds of users’ requirements.
(2)Make a two dimensional table of function and data.
(3)Apply the “QM3” to the table to nearly decompose it.
(4)Specify the function and data of each subsystem or module
and their interfaces.
(5) Extract requirements for quality with respect to each
subsystem and compose necessary quality tables.
(6) Compose a quality table and determine the quality level
of each function.
(7) Design database while taking functions into consideration.
(8) Design algorithms necessary to realize function of
subsystem to the satisfactory degree.
(9) Extract test cases considering actual operating environment.