# Design of Cognitive Assistance Systems in Manual Assembly Based on Quality Function Deployment
## 2 Literature Review
### Quality Function Deployment  
Quality function deployment (QFD) is used for customer-oriented development of products and was introduced by [PERSON] in 1966 [83], being frequently used in almost every industrial sector. The basic approach is based on the separation of product features and customer requirements. These are usually correlated [84]. One of the goals of QFD is to systematically integrate in the product development process different perspectives (interdisciplinary QFD-teams) and knowledge from different disciplines [85]. The classical approaches for QFD are the Akao approach, four-phase approach (American Supplier Institute approach) and the matrix of matrices approach. The four-phase \begin{table}
\begin{tabular}{c c c} \hline \hline
**Levels** & **Cognitive** & **Example for Cognitive Assistance** \\  & & **Functions in Assembly Processes** \\ \hline \multirow{5}{*}{1} & \multicolumn{2}{c}{Totally manual} \\  & \multicolumn{2}{c}{The user creates his/her own} \\  & \multicolumn{2}{c}{understanding of the situation and} \\  & \multicolumn{2}{c}{develops his/her course of action based on} \\  & \multicolumn{2}{c}{his/her earlier experience and knowledge,} \\  & \multicolumn{2}{c}{e.g., the user’s earlier experience} \\  & \multicolumn{2}{c}{and knowledge} \\ \hline \multirow{5}{*}{2} & \multicolumn{2}{c}{Decision-giving} \\  & \multicolumn{2}{c}{The user receives information about what} \\  & \multicolumn{2}{c}{to do or a proposal for how the task can be} \\  & \multicolumn{2}{c}{achieved, e.g., work order} \\ \hline \multirow{5}{*}{3} & \multicolumn{2}{c}{Teaching} \\  & \multicolumn{2}{c}{The user receives instructions about how} \\  & \multicolumn{2}{c}{the task can be achieved,} \\  & \multicolumn{2}{c}{e.g., checklists, manuals} \\ \hline \multirow{5}{*}{4} & \multicolumn{2}{c}{Questioning} \\  & \multicolumn{2}{c}{The technology questions the execution if} \\  & \multicolumn{2}{c}{the execution deviates from what the} \\  & \multicolumn{2}{c}{technology considers suitable,} \\  & \multicolumn{2}{c}{e.g., verification before action} \\ \hline \multirow{5}{*}{5} & \multicolumn{2}{c}{Supervision} \\  & \multicolumn{2}{c}{The technology calls for the users’ attention} \\  & \multicolumn{2}{c}{and directs it to the present task,} \\  & \multicolumn{2}{c}{e.g., alarms} \\ \hline \multirow{5}{*}{6} & \multicolumn{2}{c}{Intervene} \\  & \multicolumn{2}{c}{The technology takes over and corrects the} \\  & \multicolumn{2}{c}{action if the executions deviate from what} \\  & \multicolumn{2}{c}{the technology considers suitable, e.g.,} \\  & \multicolumn{2}{c}{thermostat} \\ \hline \multirow{5}{*}{7} & \multicolumn{2}{c}{Totally automatic} \\  & \multicolumn{2}{c}{All information and control are handled by} \\  & \multicolumn{2}{c}{the technology. The user is never involved,} \\  & \multicolumn{2}{c}{e.g., autonomous systems} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Level of automation for cognitive tasks and corresponding cognitive assistance system levels. Extended by the examples for cognitive assistance from Ref. [82]. approach is defined in Ref. [84] as a set of matrices with defined inputs and outputs (see Figure 1). The first phase involves the translation of customer requirements into measurable quality characteristics. The second phase translates the quality characteristics into components and parts of the product. At the end, these elements are prioritized based on the degree of fulfillment of the required quality characteristics. In the third phase, the manufacturing processes and specifications, which, in the fourth phase, are defined as work instructions, control plans and training requirements necessary for realization [86; 87; 88; 89; 90], are prioritized.