Verification, Validation, and Testing of Engineered Systems

2.3 VVT ACTIVITIES DURING DESIGN

The purpose of the system Design phase is to develop a technical concept and architecture for the target system. The architecture identifies the system elements and their interactions as they will be implemented, with sufficient detail to minimize the risk on the development or purchase of those elements. Creating this detail requires allocating requirements to each element and performing enough analysis and preliminary design effort to ensure the feasibility of meeting the requirements.

The remainder of this section covers VVT activities that are appropriate for the system Design phase.

2.3.1 Optimize the VVT Strategy

Objective

The objective of this activity is to optimize the VVT strategy, thereby reducing the quality cost or quality time with minimal detrimental effect on the actual quality of the engineered system. Quality cost consists of VVT costs plus failure costs, whereas quality time is the duration, on the critical path of the system lifecycle, required to develop, manufacture, maintain and dispose of the engineered system as well as perform VVT activities and remove defects from engineered systems.

Description

Generally, there is a correlation between VVT investment and system quality. Early in the 1950s, Joseph Juran (1998) proposed a qualitative model defining “quality cost” as the sum of VVT costs plus failure costs. He suggested that there is an optimal VVT strategy that will yield minimum overall quality cost (see Figure 2.5 ...