## 2 Methodology, Fundamentals, and Materials
### Functions Development during Industrial Revolutions  
The manufacturing industry profoundly impacts economic and societal progress [13]. Human society desires a progressive improvement of life quality. Industry has been advancing to keep pace with this kind of requirement. Furthermore, industry can continue to improve people's living standards by providing customized and high-quality products to consumers and setting up a better work environment for employees [1]. At the end of the 18 th century, the first industrial revolution was witnessed with the introduction of mechanical production systems using water and steam power. This was followed at the beginning of the 20 th century by the second industrial revolution with the introduction of mass production based on the division of labor with electrical energy [14]. Later, the third industrial revolution brought an increase in productivity through advanced electronics that increased calculation and storage capacities [3]. This began at the beginning of the 1970s due to the availability of electronics and IT for further centralized control of automation in production. As a result, industrial processes powered by electricity converted into standards and the use of sensors and gathering of data for monitoring of machine activity were initiated in the 1970s. Based on this capability of information exchange, the term \"Industry 4.0\" was introduced by representatives of business, politics, and academics gathered [13] that promoted the idea of digitization together with autonomy and self-behavior of machines as an approach to strengthening the competitive power of the German manufacturing industry [13]. Self-optimization is expected to improve the resilience and competitiveness of manufacturing companies [3]. The fourth wave is currently emerging with the use of cyber-physical systems. The Internet of Things and Services enables innovative, decentralized production processes for small batches and a significantly large number of product variants [14]. Industry 4.0 is based on the establishment of smart factories, smart products, and smart services embedded in an internet of things and of services also called the industrial internet [15]. Self-optimization can be regarded as the next step in control technology. Moreover, the cooperation of humans and technical systems requires a steady adaption of control structures. Therefore, self-optimization is seen as a key enabler for the next level in order to increase productivity [3]. In the 1920s, quality was only seen as product quality. There was a separate department, \"quality control\", which carried out a final inspection task, followed by the classification of non-conforming parts. With progressive industrialization and the increase in mass production in the 1930s, control methods were developed for quality assurance such as statistical process control (SPC). Quality assurance became a production task. The goal was to avoid mistakes during the production process. In the 1960s, preventive methods such as FMEA or design reviews were developed. In this way, both the quality of the product and the quality of the process began to be considered. Quality was considered then from the development and with an interdisciplinary approach. However, the main focus of quality assurance was still on the technical sector. Total quality concepts that focus on customer requirements were developed in the 1990s. All employees and the business sector must be qualified to make the right decisions. Department thinking must be replaced by process thinking. Quality is seen as a strategic factor of competition. This new understanding of quality reflects the principles of quality management. Quality management is responsible for taking measures to guarantee quality throughout the company.