Origin [edit]. The systematic use of belt color to denote the rank was first used by Kano Jigoro, the founder of judo, who first devised the colored belt system using obi (sash), and awarded the first black belts to denote a Dan rank in the 1880s. Previously, Japanese Koryu instructors tended to provide certificates.
Everything for a safe and comfortable trip. Air safety is the theory, investigation, analysis, and categorization of flight failures (aircraft incidents and accidents), and the prevention of such failures through regulation, education and training.
According to Wikipedia, the definition of Internet safety is as follows: Internet safety, or online safety, is the knowledge of maximizing the user's personal safety against security risks to private information and property associated with using the Internet, and the self-protection from computer crime in general.