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3 CONCEPT
A generic approach was chosen, where no predefined
workflow templates are given, but activities can be
documented flexibly in the form of ad-hoc workflows
with a few restrictions only, which can be formulated
at runtime (e.g. by an administrator). In line with
concepts known from LIMS, it is planned to design
a measurement line to acquire and store the measure-
ment values and a control line for assay management
and data evaluation.
Modelling shall focus on the activity that repre-
sents a concrete process step in the measurement line,
such as fabrication, separation, or characterization of
a specimen. By linking these activities, various types
of workflows can be generated. As already men-
tioned, there are no predefined workflows. They are
created by user inputs during the runtime of the sys-
tem.
3.1 Definition of Activity Types and
their Properties
To generally describe an activity, an activity type is
defined, which specifies the properties and behaviour
of its later activity instances. A property is mod-
elled by the entity AttributeType (Figure 1) and, for
instance, contains information about the data type of
this property (text, number, Boolean value, or others)
and about whether it may assume multiple values or is
mandatory. With Unit, it is possible to choose a unit
for later values of this attribute type. In this way, an
attribute type named Temperature with the data type
Number be assigned the unit ”
◦
C ”. If user input from
a pre-defined list is required as opposed to input of
arbitrary data for a certain attribute type, these values
may be defined using the entity DefaultValues.
For a better handling, the attribute types may be
grouped into categories that are represented by the en-
tity AttributeCategory.
ActivityType
has
<0:n>
<1:1>
AttributeType
DefaultValue
has
<1:1>
AttributeCategory
belongs
to
<0:n>
Unit
<1:1>
has
<0:n>
<1:1>
is_multivalue
is_mandatory
data_type
<0:n>
Figure 1: ER model for activity type definition.
3.2 Definition of Specimen Types
An activity in the measurement line always is carried
out on an object, in this concrete project, a sample
of synthetically produced nanoparticles, for instance.
These are produced in larger amounts, but may be di-
vided into any number of, also divisible, sub-sets dur-
ing their lifecycle (Figure 2). The system allows for
the definition of any specimen types, e.g. a hierar-
chical structure of batches and subordinate lots and
assays.
Material A
Assay A
Batch A Batch B
Assay DAssay C
Assay B
...
...
...
Figure 2: Division of a batch into assays.
3.3 Rules for Linking Activities
Using activity and specimen types, it is now possi-
ble to formulate rules for the linking of activities.
Figure 3 shows the respective model. Depending on
these rules, a set of possible activities is generated,
which can be carried out on a certain specimen. From
the point of view of application, such a rule may be
as follows:
• Following the activity Shipping, an activity of Ac-
ceptance of the good is required, another succes-
sive activity is not considered.
• Shipping may only be accomplished for the spec-
imen type of Assay or Lot, as a complete batch
shall never be shipped.
3.4 Runtime
After having shown how the behaviour and the prop-
erties may be configured to create a workflow, it shall
now be dealt with the modelling of the components
required during runtime (Figure 4). These are real
instances of specimens and activities as well as a re-
lationship between the activity and the attribute type.
The relationship represents the value (e.g. recorded
measurement value) of a certain attribute type (e.g.
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