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4-2. Environments
The environments in a test may be essentially affected by the
human. The environments should possibly be chosen for a reliable
and efficient execution of a test. However, this depends on the
purpose of the test. In detective tests, all errors, except the ones
to be considered, should be suppressed artificially to enable a better
detection of the disturbances to be investigated.
The environments can be divided into three main categories:
a) External environmenttemperature, humidity, vibrations,
shocks, external illumination, etc.
b) Internal environment
I) optical magnification, size and shape of the measuring
mark, internal illumination (photograph, luminous measu
ring mark),
II) initial settings of system parameters,
initial settings of driving agents (speed and direction of
handweels),
initial settings of the recording unit (position and direction
of a coordinatograph or of a polar panto
graph),
III) warming up period,
IV) internal temperature oscillations,
V) quantity of oil or fat on the lead screws, etc.
c) Human environment
I) operator's knowledge and experience in the execution of
the test,
II) his physical and psychological condition.
In comparative tests the environments should be representative
of the real and probable circumstances experienced during normal
operation. They should cover sufficiently wide ranges of the para
meters concerned.
4.3. Means
The choice of the means for the execution of a test depends
mainly on the objectives. However, detailed specifications on the
standard input or on auxiliary devices are strongly related to the
testing process which will be discussed later.
a) If a standard input is used, the structure, quantity and accuracy
of information should be defined. The structure is conditioned by
the parameters to be tested.
The structure should be chosen such that
I) in detective tests the disturbances to be investigated are
stimulated, and the test should not respond to other dis
turbances,
