## 3 Research Stream Analysis
### RS2: MC Technologies and Methods
#### 3.2.2 RS2.2: MC Technologies and Methods for Product Design  
As the design phase is generally considered a critical decision factor to the final product form, cost, reliability, and market acceptance, it is believed that MC can be best approached with an up-front effort in the early stages of the product development process [110]. The 45 papers falling in this sub-stream were reviewed to detect technologies and methods used for MC during the product design phase, following and applying the customer requirement data collection and analysis discussed in the previous paragraph, as evident in [PERSON] and [PERSON] [111]. The main results are collected in Table 3.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Author(s)**} & \multirow{2}{*}{**Year**} & **Design of** & **Use of** & **Product** & **Postponent** & \multirow{2}{*}{**Pototuping**} & **Virtual** & **Rapid** \\  & & **Product** & **Modularity in** & **Architecture** & **Design** & **Design** & **Prototyping** & **Prototyping** \\ \hline
[112] & 2011 & ✓ & & ✓ & & & & \\
[113] & 2011 & ✓ & ✓ & ✓ & & & & \\
[114] & 2011 & ✓ & ✓ & ✓ & & & & \\
[110] & 2011 & ✓ & ✓ & ✓ & & & & \\
[115] & 2011 & ✓ & ✓ & ✓ &  
The reviewed papers identify five key concepts in product design: product platform design, modular product design, product family architecture, postponement strategies, and virtual and rapid prototyping. Most studies focus on product platforms, which are seen as a central strategy for managing product variety and production efficiency. According to [PERSON] and [PERSON] [148], a product platform consists of subsystems and interfaces that enable efficient production of derivative products. This approach reduces costs, enhances material selection, and increases flexibility. While traditional platforms are \"internal,\" external platforms, i.e., products, services, or technologies that provide the foundation upon which outside firms can develop their own complementary products, technologies, or services, can also be developed for innovation [123]. Modular product design, highlighted in several studies, is an important enabler of mass customization (MC), offering benefits like flexibility, lower production times, and reduced costs [129; 135]. The concepts of product platforms, modularity, and product family architecture are interrelated, with companies often using modular design to maximize the benefits of platform-based strategies [129]. The concept of a product family, defined by [PERSON] and [PERSON] [148], involves products derived from a common platform but designed to meet specific market needs. Product families and platforms help manage increasing product variety while achieving economies of scale [114; 121]. Several papers propose frameworks and methodologies to optimize product family design and platform development, using tools like Pareto optimization and fuzzy cluster analysis [92; 110]. Postponement, also known as delayed product differentiation (DPD), is another key strategy for MC. It delays product customization until the latest point in the production flow to balance variety and cost-efficiency [5; 122]. This approach reduces complexity and forecasting errors by deferring production decisions until after orders are received. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Author(s)**} & \multirow{2}{*}{**Year**} & \multirow{2}{*}{ \begin{tabular}{c} **Design of** \\ **Product** \\ **Platforms** \\ \end{tabular}  } & \begin{tabular}{c} **Use of** \\ **Modularity in** \\ **Product** \\ **Design** \\ \end{tabular}  & \begin{tabular}{c} **Product** \\ **Family Architecture** \\ **Design** \\ \end{tabular}  & \begin{tabular}{c} **Postponement** \\ **Strategies** \\ **in** \\ **Design** \\ \end{tabular}  & \ \begin{tabular}{c} **Virtual** \\ **Prototyp-** \\ **ing** \\ \end{tabular}  & \begin{tabular}{c} **Rapid** \\ **Prototyp-** \\ **ing** \\ \end{tabular}