# DesignWIKI

Fil Salustri's Design Site

2015.01.09 11:13
research:alx3d

# ALX3d

The goal of this research area is to develop new formalisms for design processes. The solution must be descriptive, not prescriptive. It must also be as logically rigorous as possible. A family of logics known as action logics can be used to reach this goal. There is much information available in the literature and in industry that could be used to develop such a theory. In order to gather and organise all that information, a three-phase method is proposed, including best practices, pattern language, and problem-solving methods.

## Overview

Given a presumed theory for product models (such as AIMD), one may then consider formalisms for design processes themselves. Such theories would provide a logical structure for representing and reasoning about the tasks, actions, and other processes that constitute designing.

The process used to design a product affects the “design goodness” (see product centred modelling) of a product. Good products are designed using good processes. Although a good process is not sufficient for the development of a good product, it is necessary.

There is much information available in the literature and from industry on the structure and kinds of tasks used during designing. However, this information is scattered and disorganised. In order to gather and organise the information properly, a three-phase method is proposed:

1. discovery of best practices;
2. development of a pattern language; and
3. construction of problem-solving methods (PSMs).

Each phase represents an increased level of formal rigor. Once proper PSMs for design are constructed, they will be formalised with an action logic.

These phases also reflect a movement from highly industrial/practical (best practices) to highly academic/theoretic (PSMs). This means that theoretical results can be propagated back into industrial settings by reversing the development process suggested here.

This effort includes two simultaneous tasks:

1. using existing research as a guide, begin to build, top-down, a design strawman version of a standardized design process; and
2. using formal logic, begin to build, bottom-up, a formal system for the representation of design processes: the Axiomatic Design Process Model.

Each of the three phases affects these research tasks.

Another result of this research, once completed, is that there will exist a draft Body of Knowledge for design engineering.

## Basics of ALX3d

• Based on the action logic ALX3
• Action logics describe states that are traversed by actions. This allows the implicit representation of design processes so there remain more choices (in principle) and one is not as constrained as in purely prescriptive process specifications.
• [IKE00] uses signal flow graphs, which are very closely related to state/transition methods as in ALX3.

## ALX3 Notes

### Barcan Formula

• Can be written as $\forall x \Box A \Leftrightarrow \Box \forall x A$
• Read: “if everything is quantifiable in all other worlds then it would have to be necessary that everything is quantifiable in our world as well.” src

ATTENTION TODO Lots more to add; right now it's in a Circa notebook.

## To Do

• Look at action process model in [Eek00]; can/should it be absorbed?
• [MZ96] includes many “methods” that can probably be incorporated into ADPM.
• Try incorporating aspects of PIF (http://ccs.mit.edu/pif1.html)
• Life cycle phases. What do other authors have to say about the phases? Can other phase categorizations be unified?
• Chittaro et al. [CTT94] consider a multimodeling approach to be appropriate because they see reasoning about systems as a cooperative activity. This meshes with the idea of multiple agents in ADPM. Check the paper, verify, and try to incorporate their results in some way.
• Chandrasekaran and Josephson [CJ96] stress that function descriptions must not make commitments (must not refer to) product structure. How does does this relate to levels of granularity, and Dym's objectives/functions?
• In Hyman [Hym98], the phrase “client's dissatisfaction with a current situation” is used to describe the as-is world into which a new product is introduced. Can this be fit into ALX3d?
• Is a FR a constraint on functionality, whereas a plain constraint is a constraint on non-functional aspects of products? This may help distinguish between constraints, FRs, etc.
• If synthesis is a mapping from function to form, then is analysis the inverse mapping, or is it the mapping from form to performance? (Where performance is not equal to function.)
• What does it mean for a function to have a property? What kinds of properties do functions have that structures do not?
• parametric design is intimately tied to an object-oriented perspective.