Krohs_00_Pr.indd

A Device-Oriented Defi nition of Functions of Artifacts and Its Perspectives 213

effect context, we can defi ne subtypes of the goal-oriented role as a categorization of more
general functions, as shown in fi gure 12.3. Note that fi gure 12.3 shows only an is-a hier-
archy for the sake of readability, because some distinctions are independent of each other.
These differences represent different perspectives for capturing functions. When a behav-
ior is captured from a different perspective it is recognized as a different function. To some
extent it might be possible to account for the perspectivity of function ascriptions. However,
this is beyond the scope of this chapter.

12.3.2 Teleological Context

The teleological context is a generalized type of the functional context discussed in section
12.2.3 and is categorized into a function context and an unintended context. The function
context represents that the effect (behavior) is “intended” by a user. With the function
context, we can defi ne a general function as a subtype of the goal-oriented role, as shown
in fi gure 12.3. On the other hand, unintended phenomena such as faults can be defi ned a

Goal-oriented role

Effect function Quasi-function

General function Unintended phenomena

Device

function

Environmental

function

Capability

function

Effect-on-state

function

Flowing-

object

function

Essential-part

function

Effect-on-

process

function

Interpretative

function

Physical

environmental

function

Supplementary-

part function

Causal-meta

function

Partial-achievement

function

Property

enabling

function

Effect-on-

function

(meta) function

Inter-device

function

Functional

property

Function-with

way-of-

achievement

Figure 12.3
Categories of functions.