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Designing is defining. The design process transforms a desire into a description of form which will satisfy that desire.
We can model the design process very generally by the following purpose and means diagram:
This purpose and means diagram is also called a deployment of the function or purpose [design,entity].
Mathematically, this contraction mapping takes the form M : (O X C) --> O|C where O is the entity_option_set, C is the entity_selection_criteria_set, M : () --> is the entity_option_reduction_mapping, and O|C is the reduced_entity_option_set. The reduced_entity_option_set could contain a single entity_option or a family of entity_options. The design process may be one mapping or many mappings arranged in a combined serial/parallel network.
An activity (X) is the implementation of a function or purpose [X].
The design activities (generate,entity_option_set), (generate,entity_selection_criteria_set), and (generate,entity_option_reduction_mapping) are creative in nature. For example, we may generate the entity options using brainstorming. We may generate the entity selection criteria using the voice of the customer. We may generate the entity option reduction mapping using the Pugh selection matrix. The design activity (apply,(generate,entity_option_set)) is the rather mechanical process of using the contraction mapping to obtain the reduced option set. In this case we will select the option(s) from the Pugh selection process.
Our design process is thus brainstorm the entity options, obtain the selection criteria from the customers, and choose the option using the Pugh selection matrix. We could also had a design process which will use synectics to obtain the entity options, use a focus group to obtain the selection criteria, and use multiobjective optimization to select the reduced set of entity options.
The choice of the particular design process used is a result of the design of the design, often called metadesign.To Index
How can we measure design?
We can now form qualities of the form [design,entity,attribute]. A number of qualities come immediately to mind: [design,entity,cost], [design,entity,cycle_time], and [design,entity,reliability]. A number of not yet measurable high level quality elements come to mind as well: [design,entity,quality], [design,entity,value], [design,entity,prototypability], [design,entity,testability], [design,entity,producability], [design,entity,deployability], [design,entity,operability], [design,entity,supportability], [design,entity,evolveability], [design,entity,retireability], and [design,entity,manageability]. In fact, all of the design for ...s are quality elements for design. They measure the goodness of design.
Designability is the measure of the ability of the design process to design the entity. In other words, designability = [design,entity,simplicity_of_designing_entity]. This definition has been chosen to be consistent with general beliefs that operability = [operate,entity,simplicity_of_operating_entity] and supportability = [support,entity,simplicity_of_supporting_entity].
Enter the concept of design for simplicity. To achieve high levels of designability we must design the design to simply design a simple entity. This means that we should design the design of the entity and the entity at the same time. The design of the design is often called metadesign. Metadesign is the d[d] button in the genopersistation of the genopersistation.
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Originated on 970208 | Improved on 970301
Author Ed Dean |
Curator Al Motley