22
K. Watanabe et al.
elements (the product service system, users, places of use, and social conditions)
fulfill a certain set of conditions. We call such a set of conditions “value provision
conditions.” While the traditional design is to design a hardware product without
considering all these types of changes, the time axis design is to design a product
service system so as to satisfy the value provision conditions for a certain period of
time with assuming all these types of changes.
For example, we have been studying upgrade design (Umemori et al. 2001),
which extends the life of a product by upgrading some functions of the product at
the use stage in response to changes of users’ needs. We have also proposed selfmaintenance machines (Umeda et al. 1995) that can recover indispensable functions
by themselves when failure or degradation occur. They have built-in systems that can
deal with problems that arise over time. We have developed these design methods
without knowing the concept of time axis design. In this way, the concept of time
axis design has not been discussed explicitly in the design community, although it is
simple, clear, and very powerful tool for solving the sustainability issues.
2.4 Cases of Time Axis Design
2.4.1 Approach
This paper proposes a design support method for time axis design, based on cases
we collected. This is because we assume that, when a designer faces a new problem,
he or she looks for past similar cases like case-based reasoning (Agnar and Enric
1995).
Since there are few cases where the concept of time axis design is apparently
utilized in their design at present, we collected the following cases through the
Internet and literature as the cases of time axis design:
• The cases have some temporal changes.
• When some problems are caused by the temporal changes, some countermeasures
are taken or countermeasures are installed in advance during design phase.
A total of 130 cases were collected. Table 2.1 shows typical 10 examples of the
cases.
2.4.2 Classifying Time Axis Design Cases
We classified the collected cases based on the types of temporal changes and countermeasures for the temporal changes; Tables 2.2 and 2.3 indicate the types of temporal
changes and the types of countermeasures, respectively. In this paper, we focus on
temporal changes of users, design object, places of use. We do not discuss social
K. Watanabe et al.
elements (the product service system, users, places of use, and social conditions)
fulfill a certain set of conditions. We call such a set of conditions “value provision
conditions.” While the traditional design is to design a hardware product without
considering all these types of changes, the time axis design is to design a product
service system so as to satisfy the value provision conditions for a certain period of
time with assuming all these types of changes.
For example, we have been studying upgrade design (Umemori et al. 2001),
which extends the life of a product by upgrading some functions of the product at
the use stage in response to changes of users’ needs. We have also proposed selfmaintenance machines (Umeda et al. 1995) that can recover indispensable functions
by themselves when failure or degradation occur. They have built-in systems that can
deal with problems that arise over time. We have developed these design methods
without knowing the concept of time axis design. In this way, the concept of time
axis design has not been discussed explicitly in the design community, although it is
simple, clear, and very powerful tool for solving the sustainability issues.
2.4 Cases of Time Axis Design
2.4.1 Approach
This paper proposes a design support method for time axis design, based on cases
we collected. This is because we assume that, when a designer faces a new problem,
he or she looks for past similar cases like case-based reasoning (Agnar and Enric
1995).
Since there are few cases where the concept of time axis design is apparently
utilized in their design at present, we collected the following cases through the
Internet and literature as the cases of time axis design:
• The cases have some temporal changes.
• When some problems are caused by the temporal changes, some countermeasures
are taken or countermeasures are installed in advance during design phase.
A total of 130 cases were collected. Table 2.1 shows typical 10 examples of the
cases.
2.4.2 Classifying Time Axis Design Cases
We classified the collected cases based on the types of temporal changes and countermeasures for the temporal changes; Tables 2.2 and 2.3 indicate the types of temporal
changes and the types of countermeasures, respectively. In this paper, we focus on
temporal changes of users, design object, places of use. We do not discuss social