8.1 Introduction

We are almost ready to begin examining the synthetic process of creating system architecture, which starts in earnest in Chapter 9. The remaining steps we need to understand to complete Part 2 is how concept expands to architecture. Concept is a notional mapping between function and instruments of form, whereas architecture is a fairly comprehensive description of the relationships between internal functions and instruments of form.

As discussed in Chapter 7, the amount of information required to describe a system is defined by the solution-neutral functional intent and by the concept—the amount of information needed to fill in the template of Figure 7.4. The amount of information needed to describe the architecture is orders of magnitude larger. For example, the concept of a pump or that of bubblesort can be described by one line, but to describe the architecture, we need to present all of the information from Chapter 6.

Table 8.1 lists all the key questions from Chapters 4 through 7. These questionsThe questions listed in Table 1 approximately ­summarize the information needed to document an architecture. The questions are listed in the order in which they are addressed during the synthesis of an architecture. Table 8.1 includes questions about form (Chapter 4), function (Chapter 5), form-to-function mapping (Chapter 6), and solution-neutral function and concept (Chapter 7). Two new questions, 8a and 8b, are added in this chapter. These questions relate to extending an architecture from Level 1 to Level 2, and possible modularization of Level 2 objects.

Table 8.1 | Questions for defining a system in synthesis. Items in square brackets [ ] have been added to clarify the task’s relationship to concept, as introduced in Chapter 7.

  1. 7a. Who are the beneficiaries? What are their needs? What is the solution-neutral operand whose change of state will meet these needs? What are the value-related attribute and the solution-neutral process of changing the states? What are the other attributes of the operand and process?

  1. 5a. What is the primary externally delivered value-related function? The [specialized] value-related operand, its value-related states, and the [specialized] process of changing the states? What is the abstraction of the instrumental form? [What is the concept? What are several other concepts that satisfy the solution-neutral function?]

  1. 5b. What are the principal internal functions? The internal operands and processes? [What are the specializations of those processes? What are the concept fragments? What is the integrated concept? What is the concept of operation?]

  1. 5c. What is the functional architecture? How do these internal functions connect to form the value pathway? How does the principal external function emerge?

  1. 5d. What are the other important secondary value-related external functions? How do they emerge from internal functions and pathways?

  1. 4a. What is the system?

  1. 4b. What are the principal elements of form?

  1. 4c. What is the formal structure?

  1. 4d. What are the accompanying systems? What is the whole product system?

  1. 4e. What are the system boundaries? What are the interfaces?

  1. 4f. What is the use context?

  1. 6a. How are the instrument objects mapped to the internal processes? How does the formal structure support functional interaction? How does it influence emergence?

  1. 6b. What non-idealities require additional operands, processes, and instrument objects of form along the realistic internal value creation path?

  1. 6c. What supporting functions and their instruments support the instrument objects on the value creation path?

  1. 6d. What are the interfaces at the system boundaries? What operands are passed or shared? What are the processes at the interface? What are the instrument objects of the interface, and how are they related (identical, compatible)?

  1. 6e. What is the sequence of execution of process involved in delivering the primary and secondary functions?

  1. 6f. Are there parallel threads or strings of functions that execute as well?

  1. 6g. Is actual clock time important to understand operations? What timing considerations or constraints are active?

  1. 8a. How does the architecture of Level 1 extend to Level 2?

  1. 8b. What is a possible modularization of the Level 2 objects?

The main tasks in developing the Level 1 architecture are summarized in Questions 5c through 6g and discussed in Section 8.2. Then we need to recursively apply these steps to develop the Level 2 architecture and a scheme for modularization. This is the topic of Ques­tions 8a and 8b and is discussed in Sections 8.3 through 8.5.

In this chapter, we will use the air transportation system as the running example to illustrate the tasks. In Section 8.4, we will summarize the process by developing an architecture for the home data network.

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