Later process controls inventions involved basic physics principles. WHO used a precautionary approach as one of its guiding principles. Training concerns primarily the principles and techniques of auditing. Companies today are implementing these continuous delivery principles and best practices. Audio engineers must have extensive knowledge of audio engineering principles and techniques. Thomas's ethics are based on the concept of "first principles of action". CCNP Wireless covers all aspects of wireless networking principles and theory. Mies placed great importance on education of architects who could carry on his design principles. Federalism is one of the entrenched constitutional principles of Germany. Many of the same principles are applied. There are different opinions on the significance of these principles. Wagner made a major contribution to the principles and practice of conducting. It changed to forms based on Enlightenment principles of citizenship and inalienable rights. Other types of scales making use of different physical principles also exist. Nonetheless, many of the same principles apply.