216 Yoshinobu Kitamura and Riichiro Mizoguchi
“In comparison with the original design, the redesign increases the highest temperature
of the air.” (Designing time function)
The fi rst one refers to the changes of the operand’s states at a specifi c absolute location
in a time interval. The second one refers to the change while the operand fl ows from the
input port to the output port, specifi ed relative to the device. The last one is a quasi-
function. During the deployment of our framework (Kitamura, Koji, and Mizoguchi 2006),
we found that many engineers described such entities. As another example, a function of
diamond powder in a cutting machine may be described as follows:
“The diamond powder increases the friction coeffi cient of the cutting blade.” (Designing
time function)
When the cutting machine is functioning, the friction coeffi cient of the cutting blade is
high. The increase refers not to a change in the functioning time but to a comparison with
the design case without the diamond powder.
12.3.6 Quasi-Functions
We recognize the following kinds of quasi-functions. Although the authors do not consider
them as functions, it is found that a quasi-function is occasionally confused with a func-
tion. A function-with-way-of-achievement implies a specifi c way of achieving the function,
as well as the function. Examples include washing, shearing, adhering (e.g., glue adheres
A to B), linking (Hirtz et al. 2002), and “transportation by sea” (Hubka and Eder 1988),
as well as welding, as mentioned earlier. Because the meaning of such functions is impure
due to the additional meaning of how to achieve the functions, we regard them as
quasi-functions.
A functional property^5 is mainly found in the materials science domain where a material
whose function is dependent on its electronic, optical, or magnetic properties is called a
functional material (EPSRC 2005). This is (usually implicitly) based on the property
enabling function, which is based on an effect on a behavior (and/or a function) realized
thanks to a physical property. Here a property is a conceptualization of “having (a range
of) a value of an attribute.” Because a property inheres in a physical entity, we regard this
effect as a quasi-function. An example is “The high conductivity property of a conducting
wire enables its electricity-conducting behavior (and function)” (property enabling [quasi-
]function). This high-conductivity property is a necessary condition to perform the con-
ducting behavior (and function). Although such a relationship exists in all realizations of
behavior, if the property is a key factor for realizing the behavior, it might be captured as
such a quasi-function. Moreover, because there is a direct relationship between the conduc-
tive property and the conducting function, the conductive property is called a functional
property. Such a functional property provides part of the justifi cation for the device’s
capacity to perform a function discussed in section 12.2.4. In addition to the property of